Conodont and Radiolarian Data from

the De Long Mountains Quadrangle

and Adjacent Areas, Northern Alaska

By Julie A. Dumoulin,1 Anita G. Harris,2 Charles D. Blome,3 and Lorne E. Young4

Open-File Report 2006–1068

2006

Any use of trade, firm, or product names is for descriptive purposes only and does not imply

endorsement by the U.S. Government.

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

1

 U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508.

2

 U.S. Geological Survey (retired), 1523 E. Hillsboro Blvd., Apt. 1031, Deerfield Beach, FL 33441.

3

 U.S. Geological Survey, Box 25046, MS 973, Denver, CO 80225.

4 12015 North Fairwood Drive, Spokane, WA 99218.
CONTENTS

INTRODUCTION 1

DATA SOURCES 2

STRATIGRAPHIC AND STRUCTURAL SETTING 4

KUNA FORMATION AND RELATED ROCKS 6

IKALUKROK UNIT 7

Lithofacies 7

Fossil Data 8

KIVALINA UNIT 10

Lithofacies 10

Fossil Data 11

KUNA FORMATION (KEY CREEK PLATE) 12

Lithofacies 13

Fossil Data 14

DEEP-WATER FACIES OF THE LISBURNE GROUP IN THE PICNIC

CREEK ALLOCHTON 14

Lithofacies 15

Fossil Data 16

OTHER DEEP-WATER STRATA OF THE LISBURNE GROUP 17

Lithofacies 17

Fossil Data 18

KOGRUK AND UTUKOK FORMATIONS AND RELATED ROCKS 18

KOGRUK FORMATION 20

Lithofacies 21

Wolverine Creek plate, EMA 21

Key Creek plate, EMA 21

KRA 22

Fossil Data 23

Wolverine Creek plate, EMA 24

Key Creek plate, EMA 25

KRA 25

UTUKOK FORMATION AND RELATED ROCKS 27

Lithofacies 27

Wolverine Creek plate, EMA 27

Key Creek plate, EMA 27

KRA 28

Fossil Data 29

Wolverine Creek plate, EMA 29

Key Creek plate, EMA 30

KRA 30

ETIVLUK GROUP AND OKPIKRUAK FORMATION 31

ETIVLUK GROUP 31

Siksikpuk Formation 31

Otuk Formation 33

OKPIKRUAK FORMATION 36
NUKA FORMATION AND RELATED ROCKS 37

ENDICOTT GROUP 38

DEVONIAN CARBONATE ROCKS 39

THERMAL DATA 42

ACKNOWLEDGMENTS 44

REFERENCES 44

FIGURES

Figure 1. Distribution of the Lisburne Group in northern Alaska.

Figure 2. Generalized stratigraphic column for the Endicott Mountains allochthon in the

western Brooks Range.

Figure 3. Structural hierarchy for allochthons and plates in the Red Dog area.

Figure 4. Depositional setting, fossil control, and stratigraphic context of Lisburne Group

successions in the Red Dog area.

Figure 5. Age range of most biostratigraphically useful conodont and radiolarian

collections from deep-water facies of the Lisburne Group.

Figure 6. Age range of most biostratigraphically useful conodont collections from mainly

shallow-water facies of the Lisburne Group and Kayak Shale.

Figure 7. Age range of most biostratigraphically useful radiolarian and conodont

collections from the Etivluk Group and Nuka Formation.

Figure 8. Age range of most biostratigraphically useful conodont collections from

Devonian carbonate rocks.

PLATES

Plate 1. Conodonts from the Kuna Formation and related deep-water facies of the

Lisburne Group.

Plate 2. Conodonts from deep- and shallow-water facies of the Lisburne Group.

Plate 3. Conodonts from various units of the Lisburne Group and from the Kayak Shale

of the Endicott Group.

Plate 4. Conodonts from the Lisburne Group, Howard Pass quadrangle.

MAPS

Map 1. Outcrop fossil localities in the De Long Mountains and Misheguk Mountain

quadrangles.

Map 2. Drill hole fossil localities in the Su-Lik and Anarraaq areas.

Map 3. Drill hole fossil localities in the Red Dog Mine area.

Map 4. Outcrop and drill hole fossil localities in the Noatak quadrangle.

TABLES

Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation.

Table 2. Conodont samples from the Kivalina unit of the Kuna Formation.

Table 3. Conodont samples from the Kuna Formation.

Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic

Creek allochthon.

Table 5. Conodont samples from other deep-water strata of the Lisburne Group.

Table 6. Conodont samples from the Kogruk Formation.
Table 7. Conodont samples from the Utukok Formation.

Table 8. Conodont samples from unnamed strata that may correlate with the Utukok

Formation.

Table 9. Conodont samples from the Etivluk Group and Okpikruak Formation.

Table 10. Conodont samples from the Nuka Formation and related rocks.

Table 11. Conodont samples from the Endicott Group.

Table 12. Conodont samples from Devonian carbonate rocks.

Table 13. Conodont samples from the Noatak quadrangle.

Table 14. Radiolarian samples from the De Long Mountains quadrangle

Table 15. Conodonts illustrated in plates 3 and 4 from the Howard Pass quadrangle.
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CONODONT AND RADIOLARIAN DATA FROM THE DE LONG MOUNTAINS

QUADRANGLE AND ADJACENT AREAS, NORTHERN ALASKA

By

Julie A. Dumoulin, Anita G. Harris, Charles D. Blome, and Lorne E. Young

INTRODUCTION

This report presents biostratigraphic data from 289 collections at 189 localities in

the De Long Mountains, Misheguk Mountain, and Noatak quadrangles (fig. 1); most of

these data have never been previously published. The collections were made during

studies of the Red Dog massive sulfide deposit in 1998-2004 and in support of regional

mapping projects in 1979, 1981, 1983, and 1997-98. The collections—mostly conodonts

and some radiolarians—tightly constrain the age of many stratigraphic units of Devonian

through Triassic age exposed within the study area, and provide additional data on the

depositional environments and thermal history of these rocks.

The data are presented in a series of tables, organized by fossil type, stratigraphic

unit, and location. Tables 1-12 contain conodont data, mostly from the De Long

Mountains quadrangle. All of these collections were initially examined, or were

reevaluated, from 1997 through 2004, and complete faunal lists are given for all samples.

Table 13 lists ages and conodont color alteration indices (CAIs) of 27 collections from 24

localities in the Noatak quadrangle; updated faunal lists were not prepared for these

samples. Radiolarian data—all from the De Long Mountains quadrangle—are given in

table 14; these collections were analyzed between 1998 and 2003.
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Collection localities are shown in four maps (sheets 1, 2). Map 1 (sheet 1) shows

all outcrop samples from the De Long Mountains and western Misheguk Mountain

quadrangle (locs. 1-121). Maps 2-4 (sheets 1, 2) show all drill hole sample localities;

samples come from the Su-Lik deposit and in and around the Anarraaq deposit (map 2,

locs. 122-135), in and adjacent to the Red Dog deposits (Paalaaq, Aqqaluk, Main, and

Qanaiyaq) (map 3, locs. 136-158), and from drill holes along the Port Road in the Noatak

quadrangle (map 4, locs. 159-160). Map 4 (sheet 2) also shows all outcrop samples from

the Noatak quadrangle (locs. 161-189).

The text summarizes the lithofacies, age, and biofacies of the Paleozoic and

Mesozoic stratigraphic units that produced the fossil collections presented in the tables.

Many of the data for the Lisburne Group are taken from Dumoulin and others (2004).

Plates 1-4 illustrate important conodonts from the collections listed herein, as well as

from coeval collections in the Howard Pass quadrangle; information about the Howard

Pass conodonts is given in Table 15.

DATA SOURCES

The biostratigraphic samples tabulated in this report were collected during a series

of investigations spanning 25 years. Irving L. Tailleur and his co-workers Steven M.

Curtis, Inyo Ellersieck, and Charles F. Mayfield collected conodont samples during

regional mapping of the De Long Mountains quadrangle in 1979 and the Noatak

quadrangle in 1981. General ages of some of these collections were given in Curtis and

others (1990), Ellersieck and others (1990), and Mayfield and others (1987, 1990), but

these ages are herein updated and refined and faunal lists are published for these
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collections for the first time. In 1983, Anita G. Harris collected additional conodont

samples from the De Long Mountains area, and Lorne E. Young, Tailleur, and David W.

Moore collected a few conodont samples from diamond drill cores of the Su and Red

Dog deposits. John S. Kelley and his co-workers Kevin Evans, Jeanine M. Schmidt, and

Kirk W. Sherwood collected conodont and radiolarian samples as part of regional

mapping and structural investigations in the De Long Mountains quadrangle in 1997 and

1998. Most recently, Julie A. Dumoulin, Anita G. Harris, Karen D. Kelley, and David

Leach collected conodont and radiolarian samples from outcrops and drill holes in the De

Long Mountains, Misheguk Mountain, and Noatak quadrangles in support of ore deposit

studies from 1998 through 2004. Faunal lists from the 1997-2004 collections have never

been previously published, although age and biofacies data from some of these localities

were summarized in Dumoulin and others (2004).

Other fossil data from the study area are relatively sparse. Megafossil and

microfossil data from the De Long Mountains, western Misheguk Mountain, and western

Noatak quadrangles are summarized in Curtis and others (1984, 1990), Ellersieck and

others (1990), and Mayfield and others (1987, 1990). Radiolarian collections made prior

to 1984 are listed in Murchey and others (1988), and Blome and others (1988). Fossil

collections (chiefly megafossils listed in unpublished U.S. Geological Survey fossil

reports) can be found online in the Alaska Paleontological database at

http://alaskafossil.org/.

All tables in this report include lithologic descriptions of the rocks that contained

the fossils where these data were available. Petrographic descriptions based on thin

section examinations of the sampled lithologies (by J.A. Dumoulin) are also provided for
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most of the collections. Structural level of these collections (allochthon, plate, and

locally, subplate) is given where known; most of these determinations were made by L.E.

Young and may differ from those previously published by Tailleur and his co-workers.

Conodont data tables 1-12 give biofacies and conodont color alteration index (CAI) data

wherever these could be determined. These tables also include weights of most of the

samples processed for conodonts and any unusual features noted in the heavy-mineral

residues. All barren conodont samples collected from 1997 through 2004 are also

included in these tables in order to demonstrate the relative productivity of various

stratigraphic units. Locations of all fossil collections presented here were verified using

original field maps and notes of the geologists that collected them; the verified points

were then digitized and latitudes and longitudes of the locations were generated.

STRATIGRAPHIC AND STRUCTURAL SETTING

Paleozoic and Mesozoic strata of the western Brooks Range are characterized by

both stratigraphic and structural complexity; a general stratigraphic column for this area

is shown in figure 2. The Kuna Formation of the Lisburne Group hosts all massive

sulfide deposits in the Red Dog district, so the Lisburne Group was the chief focus of the

sampling reported here. The Lisburne is a chiefly Carboniferous succession that includes

both shallow- and deep-water facies and is widely distributed in outcrop and the

subsurface of northern Alaska (fig. 1). It is generally underlain by shallow-marine to

non-marine siliciclastic rocks of the Devonian-Mississippian Endicott Group. Devonian

carbonate rocks (called Baird Group by some previous workers) underlie the Endicott in

some areas, but elsewhere directly underlie the Lisburne. Deep-water shale, chert, and
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minor carbonate of the Pennsylvanian-Jurassic Etivluk Group (which includes the

Siksikpuk and Otuk Formations) overlie the Lisburne and are in turn overlain by JurassicCretaceous flysch of the Okpikruak Formation.

In the western Brooks Range, Paleozoic and Mesozoic strata are exposed in a

series of discrete structural allochthons that are in turn made up of plates, subplates, and

duplexes (fig. 3). Many nomenclatural schemes have been proposed to encompass the

structural and stratigraphic complexity of these strata; in this report, we use the

terminology of Young (2004). The Kuna Formation is mainly confined to the Endicott

Mountains allochthon (EMA; Brooks Range allochthon of some authors). Deep-water

facies of the Lisburne Group that are similar in age and lithology to the Kuna Formation

also occur in the structurally higher Picnic Creek (PCA) and Ipnavik River (IRA)

allochthons. Coeval shallow-water Lisburne facies (e.g., Utukok and Kogruk

Formations) are found mostly in parts of the Endicott Mountains allochthon and in the

structurally higher Kelly River allochthon (KRA). A fifth allochthon, the Nuka Ridge

(NRA), contains carbonate-rich strata (Nuka Formation) that are coeval with, but are not

included in, the Lisburne Group.

The disparate facies of the Lisburne Group outlined above are parts of a single

depositional system that has been structurally dismembered; Mayfield et al. (1988) and

Young (2004) have proposed the most detailed palinspastic restorations of this system.

In this paper, we use the reconstruction of Young (2004), who suggested that deep-water

facies of the Lisburne Group in the Red Dog area were deposited in an extensional basin

roughly 200 km wide by 600 km long that was flanked on the north and southwest by

carbonate platforms.
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Conodont collections from the Kuna Formation and related deep-water facies of

the Lisburne Group are in tables 1-5. Tables 6-8 contain collections from chiefly

shallow-water strata of the Lisburne Group (Utukok and Kogruk Formations and related

rocks). Samples from younger strata (Etivluk Group and Okpikruak Formation) are in

table 9. Nuka Formation samples are in table 10. Collections from older strata are found

in table 11 (Endicott Group) and table 12 (Devonian carbonate rocks). Table 13 contains

additional conodont samples from the Lisburne Group, Nuka Formation, Endicott Group,

and Devonian carbonate rocks. Radiolarian samples, all from the Kuna Formation and

related rocks and the Etivluk Group, are in table 14.

In the following sections, we briefly discuss the lithofacies, age, and biofacies of

the Devonian through Triassic strata that were sampled for this report. For a more

detailed description of the lithologies and depositional setting of the Lisburne Group, see

Dumoulin and others (2004). For a synthesis of regional tectonics and paleogeography,

see Young (2004).

KUNA FORMATION AND RELATED ROCKS

Deep-water facies of the Kuna Formation comprise the entire Lisburne Group in

the Red Dog plate and in much of the Key Creek plate of the Endicott Mountains

allochthon. In the Red Dog plate, the Kuna Formation is subdivided into informal lower

and upper units called the Kivalina and Ikalukrok, respectively (Moore et al., 1986), but

subdivisions of the Kuna are not recognized in the Key Creek plate. Deep-water facies

also comprise most or all of the Lisburne Group in the Picnic Creek and Ipnavik River
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allochthons. These strata are not generally included in the Kuna Formation and have no

formal names.

IKALUKROK UNIT (TABLES 1, 14; PLATE 1)

Lithofacies

The Ikalukrok unit makes up the upper part of the Kuna Formation in the Red

Dog plate and hosts all massive sulfide deposits in the Red Dog district. It consists

mainly of black shale and mudstone, with locally abundant intercalations of carbonate

and barite, and greatly subordinate intervals of mainly felsic volcanic rocks. The

thickness of the Ikalukrok unit ranges from <30 to >240 m. Much of the variation in total

thickness reflects variation in the amount of interbedded carbonate.

Thin-bedded to fissile shale comprises most of the lower part of the Ikalukrok

unit, and thicker bedded blocky mudstone and chert predominate in the upper beds.

Some chert and siliceous mudstone contain abundant radiolarians and (or) siliceous

sponge spicules and probably originated as biosiliceous oozes.

Two main types of carbonate layers, calcareous radiolarite and less abundant

lithic turbidite, occur in the Ikalukrok unit. Calcareous radiolarite consists of rare to very

abundant radiolarians in a carbonate matrix. Lithic turbidite consists of <5 to >50 percent

carbonate, 5 to 30 percent detrital quartz, and 20 to >50 percent other noncarbonate

material, including mud, lithic clasts, feldspar, mica, chlorite, and phosphatic grains. We

interpret most carbonate layers in the Ikalukrok as mass flow deposits, although some

thick sections of calcareous radiolarite could have formed as in situ slope or slope-basin

deposits.
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The top of the Ikalukrok unit is generally marked by a shift from black to gray

chert. In many sections, this color change coincides with a horizon of mammiform

structures that can reach 75 cm in maximum horizontal dimension, exceed 1 m in height,

and may represent fluid- and/or gas-escape conduits (Young, 2004).

The internal stratigraphy of the Ikalukrok unit has been studied in detail in the

Anarraaq deposit (Kelley and others, 2004). Three subdivisions of the Ikalukrok are

recognized in this area: (i) an upper barite interval, (ii) a middle interval of shale with

interbeds of calcareous radiolarite, lithic turbidite, and chert, and (iii) a lower sulfide

zone.

Fossil Data

Conodont and radiolarian collections indicate that the age of the Ikalukrok is late

Early-Late Mississippian (Osagean to Chesterian) (figs. 4, 5). This age is defined both by

samples from the Ikalukrok itself and from the underlying Kivalina unit and Kayak Shale

and the overlying Siksikpuk Formation (discussed below). Table 1 lists 39 conodont

samples of the Ikalukrok collected from 10 outcrop localities and 27 drill holes. Outcrop

samples produced significantly more age-diagnostic faunas than did drill hole collections

(>60% versus <25%). Additional age constraints for this unit are provided by 5

radiolarian samples from 2 outcrops and 3 drill holes (table 14, locs. 41, 65, 131, 136, and

151). Conodont biofacies denote platform margin, slope, and (or) basinal settings for the

Ikalukrok unit. Sponge spicules and (or) radiolarians replaced by pyrite and (or)

phosphate occur in a number of the heavy-mineral concentrates derived from this unit;

possible barite, fluorite, and sphalerite were also observed in a few concentrates.
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Conodont faunas of late Early Mississippian (Osagean) age were obtained from

carbonate layers and concretions in the Ikalukrok unit at several localities. A limestone

lens (loc. 4) yielded early to middle Osagean conodonts. Additional samples of lithic

turbidite and calcareous radiolarite from outcrop and Su-Lik and Paalaaq drill holes (locs.

47, 123, 139) produced conodonts with a more restricted age of middle Osagean (Sc.

anchoralis-D. latus Zone), and a fourth collection (loc. 48) has an age confined to the

upper half of that zone. All five of these assemblages denote postmortem transport from

or within outer platform, slope, and (or) basinal depositional settings. A lithic turbidite

from Anarraaq (loc. 128, sample 3) contains conodonts no older than late Osagean, as

well as redeposited older forms (middle Osagean and Kinderhookian).

The Ikalukrok unit has also yielded conodonts and radiolarians of Late

Mississippian age. Limestone turbidites(?) in outcrop produced conodonts of probable

late Meramecian-earliest Chesterian age (loc. 76). Conodonts from the upper Ikalukrok

at Su-Lik (loc. 124) are early Chesterian. Both faunas represent the gnathodid biofacies

and imply a slope depositional setting. Combined constraints from conodonts and

radiolarians in interbedded calcareous and siliceous radiolarite ≤15 m below the top of

the Ikalukrok unit (table 14, loc. 41) imply that these beds are also early Chesterian. The

age of the uppermost Ikalukrok unit in drill core is limited by two samples from DDH 50

(table 14, loc. 136). In this section, radiolarians 4 ft below the contact with the overlying

Siksikpuk Formation are no older than Chesterian and radiolarians just above the contact

are no younger than Morrowan.

Limestone turbidites in a section that may be part of the Ikalukruk unit (loc. 92)

yielded a diverse conodont fauna of middle Late Mississippian (early late Meramecian)
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age with several interesting aspects. This section has some lithologic features

characteristic of the Kuna Formation in the EMA, but others more typical of the Lisburne

Group in the PCA, and its structural level is ambiguous. The fauna, which contains

redeposited elements of Osagean age, is likewise transitional between that of the

Ikalukrok unit and the PCA Lisburne. It includes the largest single collection of the

relatively rare conodont Embsaygnathus asymmetricus Metcalfe, which has been reported

only from central Texas, northern and southwestern England, eastern Ireland, west

Malaysia, and northern Alaska. Other occurrences of Embsaygnathus and (or) the allied

form species Geniculatus claviger (Roundy) in the Brooks Range include a sample from

the Kogruk Formation in the EMA (table 6, loc. 160, sample 1) and several collections

from the Howard Pass quadrangle to the east (fig. 1). One of these samples is from

shallow-water strata of the Lisburne Group in the EMA (table 1, loc. 71 [sample

92AD33-0.2] of Dover and others, 2004); the others are all from deep-water facies of the

Lisburne in the PCA and IRA (table 1, loc. 16 of Dumoulin and others, 1993; table 1,

locs. 60, 89 [sample 92AD214-44], 91, and 92 of Dover and others, 2004).

Embsaygnathus is a shallow-water, likely warm-water conodont that may be redeposited

into deeper water settings; its rarity likely reflects its narrow stratigraphic range in the

middle Mississippian

KIVALINA UNIT (TABLE 2; PLATE 1)

Lithofacies

The Kivalina unit of the Kuna Formation consists of rhythmically interbedded,

black to gray, variably calcareous shale and gray limestone with minor intervals of
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volcanic rocks near the base of the unit. It crops out only in a 19 by 90 km area around

the Red Dog Mine, is a defining feature of the Red Dog plate, and has a maximum

thickness in outcrop of at least 122 m (Moore et al., 1986; Young, 2004). Continuous

intervals of the Kivalina unit that are >500 m thick have been drilled in the structural

hanging wall at Paalaaq (e.g., DDH 777, map 3, loc. 137), but these sections are folded,

faulted, and appear to be structurally thickened. Carbonate layers in the Kivalina unit are

mainly bioclastic supportstone (grainstone and packstone), calcareous spiculite, and

calcareous siltstone.

Depositional patterns, lithofacies, and fossils suggest that the Kivalina unit grades

downward and laterally into the Kayak Shale and upward, and perhaps laterally, into the

Ikalukrok unit. The Kivalina also grades laterally and (or) upward into unnamed units of

the Lisburne Group that are more carbonate-rich than the Kivalina sensu stricto and (or)

may have formed in somewhat shallower water. Near the southern limit of the Red Dog

plate (loc. 78, map 1), for example, strata lithologically and faunally transitional between

typical Kivalina and shallow-water facies of the Utukok Formation crop out.

Fossil Data

The Kivalina unit in both outcrop and core has yielded few age-diagnostic

conodont collections (figs. 4, 5; table 2). More than half of the 28 samples from 5

outcrops and 14 drill holes (table 2) were barren, and many productive samples contain

only meager long-ranging faunas. The most precise ages for the Kivalina unit come from

three drill holes at and north of Paalaaq (locs. 137, 138, and 142) that yielded conodonts

of middle Osagean Sc. anchoralis-D. latus Zone age. All three samples come from
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structurally complex (fault-bounded) sections, so their stratigraphic level within the

Kivalina unit is uncertain. The assemblages are all postmortem winnows, and the

collection from locality 142 indicates transport into a slope or deeper water depositional

setting. Several faunas with broader age ranges also suggest outer shelf, slope, or basin

environments (locs. 17, 122, 143).

Bioturbated bioclastic packstone at locality 78 that is transitional between typical

Kivalina unit and shallow-water facies of the Utukok Formation produced conodonts of

late Osagean-early Chesterian age. The conodonts are a postmortem winnow from a

shelf environment.

Phosphatic brachiopod fragments or pyritized bioclasts occur in one quarter of the

Kivalina unit heavy-mineral concentrates. A few concentrates contained possible fluorite

and (or) sulfide minerals.

The sparse conodont faunas that typify the Kivalina unit may, at least in part,

reflect the abundant influx of noncarbonate detritus into the Kuna basin and its environs

during Early Mississippian time. Influx of siliciclastic material generally inhibits growth

and development of normal marine faunas in carbonate platform settings (e.g., Wilson,

1975). Correlative shallow-marine strata (Utukok Formation and related rocks, tables 7,

8) are also moderately to very poorly productive of conodonts.

KUNA FORMATION (KEY CREEK PLATE) (TABLE 3; PLATE 1)

The Kuna Formation is widely exposed in the Key Creek plate of the EMA. It

crops out discontinuously from the central De Long Mountains quadrangle south into the

Baird Mountains quadrangle and as far east as the western part of the Killik River
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quadrangle (fig. 1). Throughout this extent, it is relatively uniform in character and

thickness. In the Red Dog area, it is about 60 to 110 m thick (Young, 2004). No strata

similar to the Kivalina unit are seen, and the entire formation resembles the Ikalukrok

unit of the Kuna in the Red Dog plate. A gradational depositional contact between the

Kuna Formation and the underlying Kayak Shale is widely preserved in the Key Creek

plate, both in outcrop (map 1, loc. 103) and subsurface (e.g., DDH 587, northeast of the

Main deposit, map 3, loc. 158). The upper contact of the Kuna with the Siksikpuk

Formation is also conformable and marked, as in the Red Dog plate, by a color change

and, commonly, a horizon of mammiform structures (Young, 2004).

Lithofacies

The Kuna Formation in the Key Creek plate consists chiefly of siliceous

carbonaceous shale and mudstone with subordinate intervals of carbonate and rare

volcanic rocks. Mudrocks grade locally to vitreous cherts and are petrographically and

chemically similar to mudrocks of the Ikalukrok unit (Slack and others, 2004). Much

chert likely originated as radiolarite or siliceous spiculite, but some may be silicified

carbonate. Carbonate layers are mostly organic-rich dolostone and lesser calcareous

radiolarite and spiculite. Some dolostone layers could be detrital concentrations of

dolomite crystals derived from dolomitized platform margin sediments, but most layers

probably formed during diagenesis.

Fossil Data
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Conodont and radiolarian collections define an age range of Osagean into the

Chesterian (i.e., late Early to late Late Mississippian) for the Kuna Formation of the Key

Creek plate in the Red Dog area (figs. 4, 5; table 3; table 14, locs. 72, 100, 107, 112).

Calcareous spiculite and organic-rich dolostone from the lower and middle parts of the

Kuna at two localities (locs. 24, 103) yielded conodonts of middle Osagean (Sc.

anchoralis-D. latus Zone) age. Assemblages from locality 103 (2 samples) suggest a

slope depositional environment and include a few redeposited shallow-water forms

(Eotaphrus burlingtonensis). The dolostone sample, taken about 115 ft below the top of

the Kuna Formation (loc. 24), produced a collection that likely denotes a basinal setting.

Overlapping ranges of conodonts and radiolarians in interbeds of calcareous and siliceous

radiolarite ~50 ft below the top of the Kuna Formation (loc. 107 in tables 3 and 14)

indicate that these beds are early Chesterian. At this same locality, greenish-gray chert of

the overlying Siksikpuk Formation was sampled ~150 ft above the contact with the Kuna

Formation, which is marked here both by mammiform structures and a color shift, and

contained radiolarians of probable Morrowan (Early-early Middle Pennsylvanian) age

(discussed further below under “Etivluk Group”).

DEEP-WATER FACIES OF THE LISBURNE GROUP IN THE PICNIC CREEK

ALLOCHTON (TABLE 4, PLATES 1, 2)

Strata of the Picnic Creek allochthon in the Red Dog area occur in two plates, the

Wulik and Amaruk (Young, 2004), which are generally equivalent to the sequences of

these names of Mayfield and others (1988) (fig. 3). The Lisburne Group in both plates is

in part similar to the Kuna Formation and consists mainly of chert, carbonate, and shale,
Red Dog Fossils OF 2/24/06 4:55 PM p. 15

but no formal formation names have been applied to most of these rocks. In both plates,

the Lisburne gradationally overlies (and may in part laterally grade into) the Kayak Shale

and conformably or disconformably underlies the Siksikpuk Formation (fig 4; Curtis and

others, 1984; Ellersieck and others, 1990).

Lithofacies

The Lisburne Group of the Wulik plate is well exposed northeast of Sheep

Mountain in the southeastern De Long Mountains quadrangle and in the western

Misheguk Mountain quadrangle (map 1, locs. 34, 35, 117). The Lisburne in this plate is

at least 140 m thick and resembles the Kuna Formation but contains more carbonate than

is typical of most Kuna sections. We interpret the carbonate beds as turbidites derived

from a carbonate platform margin.

According to Mayfield and others (1988) and Ellersieck and others (1990), the

Lisburne Group of the Amaruk plate consists of 80 m or less of limestone, sandy

limestone, and local sandstone (which they call Utukok and Kogruk Formations) overlain

by as much as 200 m of chert and carbonate. At locality 7 (map 1), the upper part of this

sequence is spiculitic siliceous mudstone and chert with carbonate supportstone

interbeds. Field relations and sedimentary structures suggest that the carbonates formed

as turbidites and (or) grain-flow deposits.

Additional strata in the southern De Long Mountains quadrangle are included in

the Picnic Creek allochthon based on recent mapping (De Vera and others, 2004; Young,

2004), although they were previously considered part of the Ipnavik River allochthon

(Mayfield and others, 1990). These rocks are probably part of the Amaruk plate. At
Red Dog Fossils OF 2/24/06 4:55 PM p. 16

localities 19 and 20 (map 1), the Lisburne Group is 150 to 200 m thick and consists of

interbedded chert and dolostone

Fossil Data

Conodont collections indicate that in the Red Dog area, the Lisburne Group of the

PCA is roughly coeval with the Kuna Formation in the Endicott Mountains allochthon

(figs. 4, 5). Twenty-one samples from 11 outcrop localities are listed in table 4.

Diagnostic assemblages come chiefly from the Wulik plate (locs. 34, 35, 37, 38, 117) but

also occur in Lisburne strata in the Amaruk plate (locs. 10, 19, 20). Conodonts from a

measured section (loc. 34) indicate that the basal 360 ft (~120 m) of the Lisburne in the

Wulik plate is Early Mississippian (late Kinderhookian-Osagean). More precise ages of

middle Osagean (Sc. anchoralis-D. latus Zone) come from lithologically similar strata to

the south and east in this plate (locs. 37, 38, 117). A sample near the top of the Lisburne

at loc. 34 contains conodonts of middle Late Mississippian (late Meramecian) age. A

fauna from the highest carbonate beds of the Lisburne in this area (loc. 35) is no older

than early Chesterian and includes reworked conodonts of early and middle Osagean age.

Conodonts indicate that at least part of the Lisburne section in the Amaruk plate is no

younger than Osagean (loc. 10) whereas other parts of the section in this plate are late

Meramecian (locs. 19, 20).

Conodont assemblages from the Lisburne Group in both the Wulik and Amaruk

plate generally represent postmortem winnows into quiet, deep-water environments.

Some samples (e.g., loc. 34, sample KE98-24 (+382 ft)) contain conodonts derived from

a shallow-water setting, but they occur with rare radiolarians and common sponge
Red Dog Fossils OF 2/24/06 4:55 PM p. 17

spicules that indicate a deep-water depositional environment. Phosphatic and

phosphatized rock fragments and bioclasts, including locally notable sponge spicules and

(or) radiolarians, occur in many of the heavy-mineral concentrates from this unit. Several

concentrates contained minor to abundant fluorite.

OTHER DEEP-WATER STRATA OF THE LISBURNE GROUP (TABLES 5, 14;

PLATE 2)

In addition to strata of the PCA just described, deep-water facies of the Lisburne

Group that resemble the Kuna Formation also occur in the Wolverine Creek plate of the

EMA and throughout the IRA. These facies are a subordinate component of the Lisburne

in the Wolverine Creek plate, where they are intercalated between shallow-water strata of

the Utukok and Kogruk Formations, but make up the entire Lisburne Group in the IRA

(fig. 4).

Lithofacies

An interval of black shale similar to the Ikalukrok unit of the Kuna Formation

locally overlies the Utukok Formation in exposures of the Wolverine Creek plate in the

Rok window. This unit is at least 30 m thick at localities 88 and 89 (map 1) but thins to

the north and west. The shale contains thin interbeds of finely crystalline organic-rich

dolostone and calcareous and siliceous spiculite with rare radiolarians.

In the Red Dog area, Lisburne Group strata of the IRA occur only in the

northwestern Misheguk Mountain quadrangle (De Vera and others, 2004; Nachralik Pass

sequence of Curtis and others, 1984) (fig. 3). Formal formation names have not been
Red Dog Fossils OF 2/24/06 4:55 PM p. 18

applied to these rocks, which comprise less than 100 m of chert and lesser dolostone

intruded by rare diabase sills and dikes (Curtis and others, 1984). These strata were

sampled at locality 120 (map 1), where they are mainly spiculitic chert with rare

interbeds of dolomitic calcareous radiolarite. As in other allochthons described above,

the Lisburne Group here overlies the Kayak Shale and underlies the Siksikpuk Formation

(Fig. 4, Mayfield et al., 1988).

Fossil Data

Lisburne Group facies in the Wolverine Creek plate that resemble the Kuna

Formation are of Osagean to at least Meramecian age (figs. 4, 5; tables 5, 14). Organicrich dolostone contains conodonts that are no younger than Osagean (loc. 85).

Calcareous spiculite produced late Meramecian-Chesterian conodonts; the assemblage

includes transported shallow-water forms that probably accumulated in a middle platform

or deeper water environment (loc. 89). Poorly preserved radiolarians from cherty

carbonate and siliceous mudstone in this section are of poorly constrained late Paleozoic

age (table 14, loc. 88).

Only a single diagnostic fossil collection is known from the Lisburne Group of

the IRA in the Red Dog area (figs. 4, 5). Dolomitic calcareous radiolarite (loc. 120)

produced middle Osagean (Sc. anchoralis-D. latus Zone) conodonts that have been

transported from or within a platform and/or slope setting.

KOGRUK AND UTUKOK FORMATIONS AND RELATED ROCKS
Red Dog Fossils OF 2/24/06 4:55 PM p. 19

In the Red Dog area, shallow-water facies of the Lisburne Group occur in the

Wolverine Creek plate and locally in the Key Creek plate of the EMA, and throughout

the KRA, and comprise two formations. The lower unit, the Utukok Formation, is mostly

impure limestone that weathers a distinctive yellowish orange. Abundant noncarbonate

detritus, chiefly mud and quartz silt and sand, occurs throughout the Utukok, both as

discrete beds and disseminated within carbonate layers, but the unit also contains

intervals of relatively pure limestone. The overlying Kogruk Formation is a clean gray

carbonate that is locally extensively altered to dolostone and chert. A thin interval of

deep-water strata similar to the Kuna Formation makes up the uppermost part of the

Lisburne in much of the EMA and KRA; these rocks are generally (and herein) included

in the Kogruk Formation, but have been called Kuna or Tupik Formation in parts of the

KRA (Sable and Dutro, 1961; Curtis and others, 1984; Mayfield and others, 1990).

The stratigraphic context of shallow-water Lisburne Group sections differs

somewhat between allochthons (fig. 4). Whereas the Lisburne Group in the EMA

overlies the Endicott Group, coeval strata in the KRA overlie Devonian carbonate rocks.

The Lisburne Group in both allochthons underlies the Siksikpuk Formation.

Lisburne Group strata of the Wolverine Creek plate are exposed chiefly in two

windows (Young, 1992): the Mt. Raven window north of Red Dog and the Rok window

to the south, west, and northwest. Lisburne Group rocks from this plate also form large

olistoliths along the boundary between the Wolverine Creek and Red Dog plates; several

of these olistoliths are exposed adjacent to the Red Dog Mine, and others have been

penetrated by drill holes in the Main and Aqqaluk deposits.
Red Dog Fossils OF 2/24/06 4:55 PM p. 20

Shallow-water facies of the Lisburne Group occur in the Key Creek plate west,

south, and east of the Red Dog Mine. At all of the localities we studied, deep-water strata

similar to the Kuna Formation overlie and (or) grade laterally into the shallow-water

facies.

Five plates are recognized in the KRA at three structural levels; these are, from

structurally lowest to highest, the Chimney, Amphitheatre, Wulik Peaks, Kelly, and Eli

(figs. 3, 4; Young, 2004). Our reconnaissance studies suggest that the lithofacies,

biofacies, and thickness of the Lisburne differ somewhat from plate to plate; these

differences are summarized below.

Pyrobitumen is a notable component of the Kogruk Formation, particularly in the

Wolverine Creek plate, and it has also been noted locally in the Utukok Formation. It

commonly occurs along fractures, in vugs, and between dolomite crystals in Kogruk

samples from the Rok and Mt. Raven windows and in Kogruk(?) olistoliths in the Red

Dog mine area. In some olistolith samples pyrobitumen fills fossil molds in dolostone

and chert; textural evidence suggests two episodes of hydrocarbon migration may have

affected these rocks (R. Burruss, written commun., 2002). Pyrobitumen lines vugs and

fractures in some Kogruk samples from the Key Creek plate (Port Road succession, fig.

1) and occurs in fractures and vugs in the Kogruk of the Kelly River allochthon at a few

localities in the eastern De Long Mountains quadrangle. Fractures filled with

pyrobitumin and calcite have also been found in the Utukok Formation of the Wulik

Peaks plate (J. Kelley, written commun., 1997).

KOGRUK FORMATION (TABLES 6, 13; PLATE 2)
Red Dog Fossils OF 2/24/06 4:55 PM p. 21

Lithofacies

Wolverine Creek plate, EMA: The Kogruk Formation in the Rok window consists

of ~70 to 100 m of limestone, dolomitic limestone, and dolostone (map 1, locs. 73, 75,

82, 84, 87). Similar strata occur as olistoliths that were penetrated in more than 50 drill

holes in the Main and Aqqaluk deposits (map 3, locs. 147, 148).

In the Mt. Raven window only the upper half of the Lisburne Group (Kogruk

Formation) is exposed. The section is greatly thickened by folding and repeated in

multiple thrust imbricates. Most of the section contains sedimentary features and

bioclasts indicative of a shallow-water setting (map 1, locs. 44, 45, 68). The uppermost

Kogruk in this area (map 1, locs. 42, 43?) consists of thinly interbedded dark-gray locally

phosphatic carbonate and black spiculitic chert.

Key Creek plate, EMA: In the subsurface Port Road succession (fig. 1; map 4,

locs. 159, 160), the Kogruk Formation is 100 to 150 m thick and is mainly white to lightgray dolostone with a 30-cm thick layer of green mudstone near the base. An interval of

cavernous porosity several meters thick was encountered 9 m below the top of the unit in

DDH 1104 (loc. 160). In this drill hole, the Kogruk is overlain by 14 m of black

noncalcareous shale that resembles the Kuna Formation; the nature of the contact is

uncertain but could be conformable. Brownish-gray shale of the Siksikpuk Formation is

faulted above the top of the black shale.

The Kogruk and Kuna Formations appear to interfinger in the southwestern

Misheguk Mountain quadrangle (map 1, loc. 121). The Kogruk here is massive, light-
Red Dog Fossils OF 2/24/06 4:55 PM p. 22

gray-weathering, dolomitic limestone with local chert; pelmatozoan supportstone is the

predominate lithology.

KRA: The Chimney plate is exposed chiefly as large olistoliths that underlie much

of the Wulik Peaks plate along the south and north flanks of the Wulik Peaks (map 1).

Mayfield and others (1990) included these strata in their Kelly sequence. The Lisburne

Group in this plate has been little studied; most outcrops are limestone, dolostone, and

chert of the Kogruk Formation (map 1, locs. 2, 21-23).

Rocks of the Amphitheatre plate (Amphitheatre sequence of Curtis and others,

1990) are exposed northeast of the Red Dog Mine and may be a lateral structural

equivalent of the Chimney plate (fig. 3). The Kogruk Formation in this succession (map

1, loc. 99) is more than 600 m thick (Armstrong, 1970) and consists of limestone that is

locally dolomitic and (or) cherty. Sparsely exposed black shale and subordinate

phosphatic limestone (Kuna Formation of Curtis and others, 1990) forms the uppermost

part of the Lisburne in this plate (map 1, loc. 94).

Strata referred to as Wulik Peaks plate by Young (2004) were included in the

Kelly River sequence by Mayfield and others (1990) and crop out throughout the Wulik

Peaks (map 1, locs. 6, 32, 40, 46, 56, 60, 62). This plate may be a lateral structural

equivalent of the Kelly plate (fig. 3). The Kogruk Formation is >550 m thick and is

similar to the Kogruk in the Amphitheatre plate but contains slightly less dolomite and

more chert overall. The uppermost Kogruk is only locally exposed (map 1, locs. 5, 8)

and consists of a thin interval of phosphatic black shale and chert (Kuna Formation of

Mayfield and others, 1990).
Red Dog Fossils OF 2/24/06 4:55 PM p. 23

In the Red Dog area, the Kelly plate is exposed in several thrust sheets northeast

of the Red Dog Mine. These sheets are south of, and locally thrust above the

Amphitheater plate. The Kogruk Formation (200 to 600 m thick) resembles the Kogruk

in other plates of the Kelly River allochthon (map 1, loc. 69, 110). The top of the Kogruk

is generally a fault or a recent erosional surface, but where the contact with the overlying

Etivluk Group is exposed, the uppermost Kogruk consists of black shale interbedded with

phosphatic limestone (map 1, loc. 116).

Strata of the Eli plate (Eli sequence of Mayfield et al., 1988) crop out southwest,

east, and southeast of the Red Dog Mine, in the Noatak, Misheguk Mountain, and Baird

Mountains quadrangles (Fig. 1). The Lisburne Group in this plate has been studied in

detail only in the Baird Mountains quadrangle (Dumoulin and Harris, 1992), where it is

most similar to the Lisburne of the Kelly plate.

Fossil Data

Conodonts indicate an age of Osagean-Chesterian for the Kogruk Formation in

the Red Dog area (figs. 4, 6). Forty-eight conodont samples were taken from 41 localities

in the Kogruk (table 6; table 13, locs. 161, 162). In addition, carbonate breccia in the

Okpikruak Formation produced a conodont assemblage of mixed age derived in part from

a Mississippian source (table 9, loc. 62), most likely the Kogruk Formation or related

rocks. Kogruk collections were made from outcrop and drill holes in both the Key Creek

and Wolverine Creek plates of the EMA and from outcrops of the Chimney,

Amphitheatre, Wulik Peaks, and Kelly plates of the KRA. Only 3 of these samples were

barren, and more than half produced biostratigraphically useful faunas. Phosphatic and
Red Dog Fossils OF 2/24/06 4:55 PM p. 24

phosphatized rock fragments and bioclasts (including phosphatic brachiopods and

ichthyoliths, as well as phosphatized bryozoan and crinoid fragments and spine,

ostracode, gastropod, and pelecypod steinkerns) are a notable component of many of the

heavy-mineral concentrates from this unit, particularly those from the uppermost part of

the Kogruk. Minor glauconite also occurs in two concentrates from the uppermost

Kogruk in the KRA.

Wolverine Creek plate, EMA: Table 6 includes 13 samples from 12 localities in

the Kogruk of the Wolverine Creek plate; conodonts indicate that the unit is largely

Meramecian-early Chesterian but is, in part, locally Osagean (figs. 4, 6). Olistoliths of

brecciated dolostone that resemble the Kogruk Formation were sampled in the Aqqaluk

(DDH 550, loc. 147) and Main (DDH 605, loc. 148) deposits and produced conodonts of

Kinderhookian-Osagean age that are typical of a high-energy, shallow-water

environment. Dolomitic skeletal packstone at the base of the Kogruk Formation in the

northwestern part of the Rok window yielded late middle-early late Osagean conodonts

characteristic of a platform depositional setting (loc. 73 [KE98-25B]). Crinoidal

dolostone in the upper part of the Kogruk in both the Mt. Raven and Rok windows

contains conodonts that denote shallow-water, partly restricted to high-energy

environments (locs. 45, 75). Dolostone with phosphatized bioclasts at the top of the unit

in both windows (locs. 42, 73[KE98-25A]) yielded conodont faunas that indicate slope

and outer platform or deeper settings, respectively. The age of the uppermost Kogruk is

best constrained in the Rok window, where both shallow-water and overlying deeper

water conodont faunas are likely of very early Chesterian age (figs. 4, 6). Equivalent
Red Dog Fossils OF 2/24/06 4:55 PM p. 25

collections from the Mt. Raven window produced less precise ages of late Meramecianearly Chesterian. A single sample from the Rok window, from strata thought to be upper

Kogruk, yielded atypically old conodonts of late Late Devonian-early Early

Mississippian age that may have been reworked from underlying strata (loc. 82).

Key Creek plate, EMA: Four samples from 3 localities in table 6 (locs. 121, 159,

160) constrain the age of the Kogruk Formation in the Key Creek plate. Conodonts from

the upper part of the Kogruk in the Port Road succession (loc. 160) are late Osageanearly Meramecian, possibly early Meramecian; taphonomy of this assemblage implies a

relatively shallow-water setting. In the southwestern Misheguk Mountain quadrangle

(loc. 121), dolomitic pelmatozoan supportstone (Kogruk Formation?) that appears to

grade laterally into the Kuna Formation yielded a Meramecian-early Chesterian conodont

assemblage that suggests an inner to middle platform depositional setting.

KRA: Tables 6 and 13 include 31 conodont samples from 26 localities in the

Kogruk Formation of the KRA. Collections represent the Chimney (5), Amphitheatre

(3), Wulik Peaks (10), and Kelly (4) plates; 7 samples were taken from probable KRA

strata for which the plate is uncertain. Fossil data presented here and elsewhere denote an

age of late Osagean to Meramecian for most of the Kogruk in the KRA (Dumoulin and

others, 2004), but the upper part of the unit is at least locally Chesterian (figs. 4, 6).

Age-diagnostic conodont faunas from the Kogruk Formation in the KRA are

chiefly Late Mississippian. Conodonts from the basal(?) Kogruk of the Chimney plate

are no younger than Osagean (loc. 21), but higher beds in this plate are of probable late
Red Dog Fossils OF 2/24/06 4:55 PM p. 26

Meramecian age (loc. 22). Late Meramecian conodonts occur in samples from the Wulik

Peaks plate (locs. 6, 40) and faunas of late Meramecian-Chesterian age were obtained

from the Wulik Peaks (locs. 32, 46, 62) and Kelly (loc. 69; table 13, loc. 162) plates.

KRA strata for which the structural plate is uncertain also produced conodonts of late

Meramecian-Chesterian (locs. 113, 114) age. Conodont assemblages from the Kogruk in

the Chimney, Wulik Peaks, and Kelly plates suggest deposition in shallow to moderate

water depths with locally restricted circulation and, in the Chimney plate, some highenergy conditions.

The uppermost Kogruk Formation in the Kelly River allochthon is at least in part

of late Late Mississippian (Chesterian) age. Dark limestone, chert, and (or) shale that

locally occur at the top of the unit contain early Chesterian conodonts in the

Amphitheater and Kelly plates (locs. 94, 116). Conodonts of late Meramecian-very early

Chesterian age that indicate the gnathodid biofacies are found at the top of the Kogruk in

the Wulik Peaks plate (loc. 8). All of these strata, like equivalent rocks in the upper

Kogruk of the EMA discussed above, formed in a relatively deep-water setting

(Dumoulin and others, 2004). The facies shift recorded in these beds is part of a regional

drowning of carbonate platforms that occurred throughout the western and west-central

Brooks Range in latest Meramecian to earliest Chesterian time (Dumoulin and Harris,

1992; Dumoulin and others, 2004).

A single collection from bioclastic supportstone confidently assigned to the

Kogruk Formation but of uncertain structural position (loc. 93) produced conodonts of

late Chesterian (Rh. muricatus Zone through Rh. primus Zone) age that suggest

derivation from a relatively shallow-water setting. These rocks are on trend with and
Red Dog Fossils OF 2/24/06 4:55 PM p. 27

adjacent to strata of the KRA, but occur close to a major fault zone (Curtis and others,

1990). The CAI of this assemblage (3.5-4) is considerably higher than that from

collections on trend to the southwest and northeast (e.g. CAI=2-2.5 and ≤2.5 at locs. 94

and 116). Whatever the structural level of these late Chesterian strata, they indicate that

shallow-water platform carbonate deposition recurred in, or perhaps persisted into, latest

Mississippian time in at least some parts of the De Long Mountains area.

UTUKOK FORMATION AND RELATED ROCKS (TABLES 7, 8, 13; PLATES 2, 3)

Lithofacies

Wolverine Creek plate, EMA: In the Rok window, the Utukok Formation consists

of ~120 m of limestone, locally argillaceous and (or) sandy, interbedded with shale,

calcareous shale, and siltstone (map 1, locs. 63, 64, 73, 74, 83). Limestone, in wavy to

nodular partly bioturbated beds 5 to 20 cm thick, includes skeletal wackestone,

packstone, and grainstone. Some samples contain >10-15 percent non-calcareous mud,

silt, and sand; coarser detritus is mainly quartz and lesser white mica. Throughout the

Utukok in this plate, zones rich in lime mud are partly altered to chert and (or) dolomite,

and the uppermost beds of the formation are often pervasively dolomitized and (or)

silicified.

Key Creek plate, EMA: In the Port Road succession, the Utukok Formation is

about 150 m thick and conformably overlies the Kayak Shale (DDH 1103, map 4, loc.

159). It comprises light- to medium-gray limestone that is locally partly silicified and

(or) partly dolomitized and has 5-15 percent gray to black shale interbeds that are 2 mm-
Red Dog Fossils OF 2/24/06 4:55 PM p. 28

2.5 m thick. Skeletal packstone and grainstone makes up much of the unit, but sparsely

bioclastic wackestone is common in shale-rich intervals. Shale layers contain trace

amounts of quartz silt and sand.

The Utukok Formation also occurs in the Key Creek plate west of the Red Dog

Mine (map 1, loc. 31). Here, it consists of orange-weathering limestone with notable

interbeds of shale and (or) sandstone and overlies the Kayak Shale. Similar rocks in the

Key Creek plate south of the Red Dog Mine (map 5, loc. 172) were provisionally

included in the Utukok by Dumoulin and others (2004).

KRA: No strata equivalent to the Utukok Formation have been recognized in the

Chimney plate. The lower part of the Lisburne Group in the Amphitheatre plate is a

distinctive sequence of dark-gray, argillaceous limestone and carbonaceous shale

(micritic limestone unit of Curtis et al., 1990). These rocks (map 1, locs. 95, 96, 98, and

99) are coeval with and resemble the Utukok in some ways but have not been formally

included in that unit. The Utukok in the Wulik Peaks plate is mostly limestone with

locally abundant shale and sandstone interbeds (map 1, locs. 40, 52-56, 62, 81). Shale is

less carbonaceous than that in the Utukok of the Amphitheater plate. Sandstone generally

contains ≤30-40 percent non-carbonate detritus, but siliciclastic-dominated sandstones

occur locally in the southern Wulik Peaks (Mayfield et al., 1990). The Lisburne Group in

the Kelly plate (map 1, locs. 9, 70, 102) generally resembles that in the Wulik Peaks

plate. However, the Utukok in the Kelly plate has less interbedded shale, more

noncarbonate silt and sand, and more diverse bioclasts than coeval Wulik Peaks sections.

The Utukok in the Kelly plate may reach 1000 m in thickness, according to Curtis and
Red Dog Fossils OF 2/24/06 4:55 PM p. 29

others (1990). The Utukok in the Eli plate is at least 180 m thick and consists of

limestone, quartzose to calcareous sandstone, and subordinate siltstone and shale. In the

Baird Mountains, siliciclastic rocks make up about 40 percent of the section and include

an interval of relatively pure quartz arenite that is 10 m thick and at least 12 km long.

Fossil Data

Conodonts and other fossils suggest that the Utukok Formation in the Red Dog

area is chiefly Kinderhookian and Osagean (figs. 4, 6; Dumoulin and others, 2004).

Thirty-three conodont samples from 28 localities in the Utukok are included in this study

(table 7; table 13, loc. 166). These collections come from the Wolverine Creek and Key

Creek plates of the EMA, the Wulik Peaks, Kelly, and Eli plates of the KRA, and six

localities for which the structural level is unknown. An additional 6 samples from 5

localities (table 8) were taken from rocks that may correlate with the Utukok Formation

in the Key Creek plate (EMA) and Amphitheatre plate (KRA). About one-quarter of our

samples from the Utukok and related strata were barren, and less than half produced

relatively tightly constrained ages. Almost two-thirds of the heavy-mineral concentrates

from the Utukok samples contained phosphatic, phosphatized, and (or) pyritized bioclasts

including ichthyoliths and phosphatic brachiopods, and phosphatized foraminifers,

ostracodes, spines, and bryozoan and pelmatozoan fragments. A few concentrates

contained fluorite.

Wolverine Creek plate, EMA: Table 7 includes 6 samples from the Utukok

Formation in the northwestern part of the Rok window. The most diagnostic collections
Red Dog Fossils OF 2/24/06 4:55 PM p. 30

are of Osagean age and indicate a shallow-water, locally restricted depositional setting

(locs. 63, 64, 73).

Key Creek plate, EMA: Five samples (tables 7, 8) constrain the age of the Utukok

Formation and possibly stratigraphically equivalent rocks in the Key Creek plate. A

collection ~30 m below the top of the Utukok in the subsurface Port Road succession

(DDH 1103, sample 3, loc. 159) is middle to middle late Osagean and represents

postmortem transport within or from a high-energy depositional setting. Conodonts from

skeletal supportstone near the base of the Utukok in outcrop west of the Red Dog Mine

(loc. 31) are also middle to middle late Osagean. Pelmatozoan-bryozoan grainstone from

a similar stratigraphic level in the Noatak quadrangle (table 8, loc. 172) produced

Osagean, possibly middle to late Osagean, conodonts.

KRA: Conodont collections from the Utukok Formation in the KRA reported here

include 10 samples from the Wulik Peaks plate, 3 samples from the Kelly plate, and 2

samples from the Eli plate. The oldest faunas, of middle to late Kinderhookian age, come

from the Eli plate (loc. 167; table 13, loc. 166). Several olistoliths of uncertain structural

provenance (locs. 18, 25) yielded coeval conodonts. One of the Eli plate collections (loc.

167) indicates a high-energy, shallow-water depositional regime, whereas the olistolith

faunas suggest postmortem transport into middle shelf or deeper, relatively quiet water.

Most Utukok Formation conodont assemblages from the KRA are of Osagean age and

imply shallow-water, locally restricted to high-energy environments. A fauna from the

Kelly plate indicates an early Osagean age (loc. 102). Other collections, from the Kelly

(loc. 9) and Wulik Peaks (loc. 52) plates, are middle-late Osagean and one Wulik Peaks

sample (loc. 62) is no older than late Osagean. Foraminifers imply that the uppermost
Red Dog Fossils OF 2/24/06 4:55 PM p. 31

Utukok in parts of the Wulik Peaks plate could be as young as early Meramecian

(Dumoulin and others, 2004) and a lithostrotionid coral from correlative beds of

uncertain structural position (loc. 57) is also Late Mississippian. Strata equivalent to the

Utukok in the Amphitheater plate (table 8, locs. 95, 96, 98, and 99) have produced no

precisely dated conodonts or other fossils (Dumoulin and others, 2004).

ETIVLUK GROUP AND OKPIKRUAK FORMATION

ETIVLUK GROUP (TABLES 9, 14)

The Pennsylvanian-Jurassic Etivluk Group (Mull and others, 1982) overlies the

Lisburne Group in all allochthons that contain sedimentary rocks (figs. 2, 4) and includes

the Siksikpuk and overlying Otuk Formations (fig. 2). These formations are relatively

easy to differentiate in the EMA, but can be difficult to distinguish in other allochthons.

Mull and others (1987) defined the Imnaitchiak Chert to encompass chert-dominated

sections correlative with both the Siksikpuk and the Otuk Formations in these higher

allochthons.

Siksikpuk Formation

In the western Brooks Range, the Siksikpuk Formation in the EMA (Red Dog and

Key Creek plates) is ~70 to 100 m thick and consists of four informal subunits (Young,

2004). The lower subunit (20 to 40 m thick) is bright-orange-weathering, dark-gray to

blue-gray chert that grades upward to black shale and chert overlain by light-gray

siliceous shale and chert. Local layers of brown-weathering carbonate rock—mostly

coarse-crystalline iron-rich dolostone—also occur in this subunit. Laminated to thin-
Red Dog Fossils OF 2/24/06 4:55 PM p. 32

bedded greenish-gray and maroon aluminous shale and lesser chert (23 to 46 m thick)

makes up the middle subunit. The upper subunit (9 to 46 m thick) comprises greenishgray and maroon chert. A transitional subunit (≤8 m) at the top of the Siksikpuk consists

of laminated green-gray, brown-gray, and lesser maroon shale and subordinate chert with

a few thin lenses of chert-rich siltstone; these rocks conformably underlie and locally are

interbedded with the basal Otuk Formation. Minor barite, as layers, rosettes, and veins,

occurs throughout the Siksikpuk. The Siksikpuk in the Wolverine Creek plate of the

EMA resembles correlative strata in the Red Dog and Key Creek plates but is thicker (up

to 165 m) and may contain siltstone in the lower subunit (Young, 2004).

The informal subunits of the Siksikpuk Formation described by Young (2004) can

also be recognized in at least some parts of the Kelly River allochthon. In other

allochthons, however, the Siksikpuk generally consists of 10 to 30 m of chert that cannot

be readily subdivided and is difficult to distinguish from the Otuk Formation.

Mainly Pennsylvanian and Permian ages have been reported from the Siksikpuk

Formation and equivalent strata of the lower Etivluk Group (or lower Imnaitchiak Chert)

in the western Brooks Range (Curtis and others, 1984, 1990; Ellersieck and others, 1984,

1990; Mayfield and others, 1984; Dover and others, 2004; Young, 2004). Our data

constrain the age of the lower subunit of the Siksikpuk in the EMA (Key Creek and Red

Dog plates) and the middle(?) subunit of the Siksikpuk in the KRA (Wulik Peaks plate)

(fig. 7). Radiolarians (table 14, locs. 72, 107 [97AK74O-S]) indicate an age of late Late

Mississippian to early Middle Pennsylvanian (Chesterian to Morrowan) for samples of

predominantly gray chert from the base to ~10 m above the base of the lower subunit in

the Key Creek plate. Grayish-green chert ~46 m above the base of the Siksikpuk, from
Red Dog Fossils OF 2/24/06 4:55 PM p. 33

strata lithologically transitional between the lower and middle subunits (table 14, loc. 107

[97AK74T]), contains radiolarians of probable Early-early Middle Pennsylvanian

(Morrowan) age. Roughly coeval but less diagnostic radiolarian faunas indicate a

slightly broader age range of Late Mississippian-early Middle Pennsylvanian

(Meramecian to Morrowan) for drill core samples from equivalent strata (gray to black

chert) in the Red Dog plate (table 14, locs. 136, 150). Brownish-gray carbonate in the

basal Siksikpuk Formation in the Wolverine Creek plate of the EMA (table 9, loc. 67)

was sampled for conodonts but was barren; this carbonate layer resembled altered

(calcitized) volcanic rock in thin section. A section of maroon and light-greenish-gray

shale and lesser chert that may represent the middle subunit of the Siksikpuk in the KRA

(Wulik Peaks plate) (table 14, loc. 61) produced late Early-middle Middle Permian

(middle Leonardian-middle Guadalupian) radiolarians.

Otuk Formation

The Otuk Formation in the EMA in the western Brooks Range is ~45 m thick and,

like the Siksikpuk Formation, can be divided into four informal subunits (Young, 2004)

that generally correlate with the shale, chert, limestone, and Blankenship members of

Mull and others (1982) and Blome and others (1988). The lower subunit (generally 9 to

26 m thick) consists of color-banded black and greenish-gray shale, lesser chert, and

minor rusty-weathering dolostone that contains beds, rosettes, and needles of barite.

Gray chert makes up most of the middle subunit, (~20 m thick) with a distinctive

recessive zone (1 to 5 m thick) of laminated black chert and shale in the middle of the

subunit. The upper subunit is generally thin or absent in the Red Dog plate, but may
Red Dog Fossils OF 2/24/06 4:55 PM p. 34

reach a thickness of 15 m in the Wolverine Creek plate (Young, 2004). It is mainly

yellow- to buff-weathering dolostone, limestone, and limy chert with locally abundant

monotid pelecypods. The Blankenship member, the uppermost subunit of the Otuk

Formation, occurs locally in the Red Dog plate and comprises 3 to 6 m of laminated

black chert and shale.

In higher allochthons, the Otuk Formation generally consists mainly of chert and

the subunits recognized in the EMA can be difficult to discern. In the Kelly River

allochthon, however, the recessive zone of the middle subunit is present at least locally

and the subunits described above can be distinguished.

Fossils of Triassic and (locally) Jurassic age are known from the Otuk Formation

and correlative strata assigned to the upper Etivluk Group or upper Imnaitchiak Chert

(Curtis and others, 1984, 1990; Ellersieck and others, 1984, 1990; Mayfield and others,

1984, 1990; Blome and others, 1988; Dover and others, 2004). Young (2004) reported

inferred age ranges of Early-Middle Triassic (early Smithian to Ladinian) for the lower

subunit, Middle(?)-Late Triassic (Ladinian? to Norian) for the middle subunit, middle

Late Triassic (middle to late Norian) for the upper subunit, and Early-early Middle

Jurassic (Sinemurian to middle Bajocian) for the Blankenship member. The uppermost

part of the Imnaitchiak Chert yields radiolarians of Early Jurassic (Hettangian or

Sinemurian and Pliensbachian or Toaracian) age in the Howard Pass quadrangle (Dover

and others, 2004).

Data presented in this report limit the age of the Otuk Formation in the EMA,

PCA, and KRA, and agree with the age distributions outlined above (fig. 7). In the Red

Dog plate of the EMA, dark-gray chert interbedded with shale in the middle(?) subunit of
Red Dog Fossils OF 2/24/06 4:55 PM p. 35

the Otuk Formation produced radiolarians of late Carnian to middle Norian age (table 14,

loc,. 152). Interbedded chert and dolostone in the upper subunit in this plate yielded

Monotis(?) sp., conodonts, and radiolarians; the radiolarians restrict the age of these strata

to middle Late Triassic (late middle-early late Norian) (tables 9, 14, loc. 66).

Radiolarians of late Middle-early Late Triassic (late Ladinian to early Carnian) age were

obtained from a drill core sample of gray chert from the middle subunit of the Otuk

(below the recessive marker) in the Wolverine Creek plate (table 14, loc. 126). Conodont

samples from cherty carbonate in the upper subunit of the Otuk at this locality and a

nearby drill hole (table 9, locs. 126, 127) were barren.

Etivluk Group sections from the PCA sampled for this report consist mainly of

chert and produced faunas correlative with those from the middle and upper subunits of

the Otuk Formation in the EMA. Samples of gray-green chert from the Wulik Peak plate

of the PCA yielded radiolarians of late Middle Triassic (probable middle to late Ladinian)

and early Late Triassic (probable early to middle Carnian) ages (table 14, loc. 35). Late

Late Triassic (late Norian or Rhaetian) radiolarians were found in grayish-black siliceous

mudstone in this plate (table 14, loc. 33). Buff-colored bivalve wackestone that contains

Late Triassic bivalves (monotids and Palaeocardita(?) sp.) as well as conodonts of

probable middle Late Triassic age (table 9, loc. 36) is also most likely part of the PCA;

the conodonts in this collection indicate a slope or basin depositional setting.

A section of Otuk Formation in the Wulik Peaks plate of the KRA was also

sampled for this study (table 14, loc. 5). Gray chert from the middle subunit, below the

recessive marker, produced Middle Triassic (middle to late Ladinian) radiolarians; gray
Red Dog Fossils OF 2/24/06 4:55 PM p. 36

and white chert from the middle(?) subunit, above the recessive marker, contained early

Late Triassic (early to middle Carnian) radiolarians.

Heterolithic carbonate breccia (table 9, loc. 62) from the Cretaceous-Jurassic

Okpikruak Formation (further discussed below) yielded a mixed-age conodont collection

derived in part from a Triassic source that is most likely the lower subunit of the Otuk

Formation. The conodonts are of middle Early Triassic (Smithian) age and normalmarine, middle-shelf or deeper water biofacies. Slightly younger (latest Early Triassic;

latest Spathian) conodonts are the oldest fossils known from the Otuk in the De Long

Mountains area (Mayfield and others, 1990); this fauna comes from the EMA (Red Dog

plate) (Young, 2004). However, Bodnar (1984) reported conodonts of latest Dienerianearliest Smithian, middle Smithian, and late Smithian age from the lower (shale) subunit

of the Otuk (EMA) in the north-central Brooks Range. The outcrop of the Okpikruak that

yielded the carbonate breccia appears to be part of the KRA, but the structural unit that

produced the Triassic conodonts is unknown.

OKPIKRUAK FORMATION (TABLE 9)

The Okpikruak Formation, of Jurassic-Cretaceous age, is a sequence of mudstone,

siltstone, sandstone, and local polymict conglomerate at least 300 m thick that was

deposited during the Brookian orogeny in a deep-marine setting (Young, 2004). It

overlies, disconformably to unconformably, the Etivluk Group and older rocks. Some

parts of the Okpikruak contain large (meter- to outcrop-sized) blocks of various

lithologies that have been interpreted as olistoliths (Young, 2004). Okpikruak clasts and

blocks reflect a diverse provenance including numerous stratigraphic units and
Red Dog Fossils OF 2/24/06 4:55 PM p. 37

allochthons. A single carbonate boulder from this unit (table 9, loc, 62) produced

conodonts derived from strata of at least three ages: Mississippian, earliest Early-Middle

Pennsylvanian, and middle Early Triassic. The most likely sources for these conodonts

are, respectively, the Kogruk, Nuka, and Otuk Formations; details of these correlations

are discussed in the sections of this paper devoted to these units.

NUKA FORMATION AND RELATED ROCKS (TABLES 10, 13)

The Nuka Formation (Carboniferous) consists of medium- to coarse-grained,

variably glauconitic limestone, arkosic limestone, and variably arkosic sandstone (Curtis

and others, 1984; Young, 2004). It is recognized only in the Bogie plate (sequence) of

the NRA (Mayfield and others, 1988), but a somewhat similar unnamed unit (map unit

MDl5 of Curtis and others, 1984) occurs in the Bastille plate (sequence) of the NRA (fig.

3). Unit MDl5 (Mississippian and (or) Devonian limestone) consists mainly of locally

glauconitic limestone with some interbeds of fine- to coarse-grained feldspathic

sandstone.

Studies of conodonts and foraminifers suggest that the depositional age of the

Nuka is Late Mississippian-Middle Pennsylvanian (late Meramecian-early Atokan)

(Curtis and others, 1984; Mayfield and others, 1984, 1987, 1990; Young, 2004). Only

fossils of Devonian age, including Middle-early Late Devonian corals and brachiopods

and Late Devonian foraminifers, have been reported from unit MDl5 (Curtis and others,

1984).

Tables 10 and 13 contain conodont data from the Nuka Formation and unit MDl5

(fig. 7). Two Nuka localities in the Noatak quadrangle yielded faunas of late
Red Dog Fossils OF 2/24/06 4:55 PM p. 38

Meramecian-early Atokan age (table 13, locs. 163, 165). A Nuka sample from the De

Long Mountains (table 10, loc. 16) produced a more definitive fauna no older than early

Middle Pennsylvanian (late Morrowan) in age that also contained redeposited late Late

Mississippian (Chesterian) forms. Two samples of skeletal supportstone from unit MDl5

were barren (table 10, locs. 118, 119).

A heterolithic carbonate boulder in the Okpikruak Formation (table 9, loc. 62)

produced some conodonts of earliest Early-Middle Pennsylvanian (earliest Morrowanearly Desmoinesian) age. The Nuka Formation is the only carbonate-rich unit in the

western Brooks Range that has yielded conodonts of this age and is thus the most likely

source for this fauna.

ENDICOTT GROUP (TABLES 11, 13; PLATE 3)

The Endicott Group is a chiefly siliciclastic succession deposited mainly in

shallow-marine to non-marine settings. It comprises, in ascending order, the Hunt Fork

Shale, Noatak Sandstone, Kanayut Conglomerate, and Kayak Shale (fig. 2). Much of the

Endicott consists of fluvial and marginal marine sandstones and conglomerates that

contain few fossils, but marine shales in the Hunt Fork and Kayak include some

bioclastic limestone layers. Megafossils (chiefly brachiopods) indicate a Late Devonian

age for the Hunt Fork and the Noatak in the western and west-central Brooks Range; the

Kanayut is considered Late Devonian-Mississippian(?) (Ellersieck and others, 1984; Karl

and others, 1989; Dutro and others, 1994). The Kayak is well-dated as early Early

Mississippian (Kinderhookian) in the west-central Brooks Range (e.g., Dumoulin and
Red Dog Fossils OF 2/24/06 4:55 PM p. 39

Harris, 1997; Mull and others, 1997) but few definitive age data have been published

previously from the De Long Mountains.

Tables 11 and 13 contain 15 samples from 14 locations in the Kayak Shale.

Collections are chiefly from the EMA (Key Creek and Wolverine Creek plates) but

several are from the PCA (Amaruk plate). Six collections (table 11, locs. 15, 158, 175,

177, 178; table 13, loc. 174) from the Key Creek and Amaruk plates produced diagnostic

faunas; all are Kinderhookian, and three are middle-late Kinderhookian (figs. 4, 6).

Kayak lithofacies sampled for this report range from skeletal wackestone to grainstone

with a variety of bioclasts. Most samples contain notable (10 to 25%) quartz and other

noncarbonate detritus. Conodont biofacies from the EMA suggest shallow-water settings

locally characterized by high-energy conditions and restricted circulation. Two samples,

one from the Port Road succession of the Key Creek plate (loc. 159) and the other from

the Amaruk plate (loc. 15) are phosphatic lag concentrates; the latter was deposited in a

middle-shelf or deeper setting. Phosphatic, phosphatized, and (or) pyritic bioclasts are a

notable component of heavy-mineral concentrates from most Kayak samples.

Very fine to fine-grained sandstones in the Hunt Fork Shale and Noatak

Sandstone (table 11, locs. 90, 105) contained sparse brachiopod fragments but were

barren of conodonts. Clasts in both samples are chiefly monocrystalline quartz with

subordinate polycrystalline quartz and sedimentary lithoclasts. The Hunt Fork sample

also contains mafic volcanic lithoclasts including possible tuff fragments.

DEVONIAN CARBONATE ROCKS (TABLES 12, 13)
Red Dog Fossils OF 2/24/06 4:55 PM p. 40

Carbonate strata of Devonian age are found in a number of thrust sheets in the

western Brooks Range and consist of locally fossiliferous limestone and dolostone with

some siliciclastic interbeds (e.g., Mayfield and others, 1987, 1988). Samples of these

rocks in this study come from the EMA, PCA (Amaruk plate), KRA (Amphitheatre,

Kelly, and Wulik Peaks plates), and NRA, as well as some strata of uncertain structural

position; collections are from the De Long Mountains (table 12, 15 samples from 13

localities) and Noatak (table 13, 12 samples from 11 localities) quadrangles. Many of

these rocks have been called Baird Group by previous authors (e.g., Mayfield and others,

1984, 1988) but most differ from the Baird Group in its type area in the Baird Mountains

quadrangle in age, metamorphic grade, and stratigraphic and structural position. The

type Baird Group is Ordovician to early Middle Devonian (mostly Early Devonian and

older), metamorphosed (conodont CAI values ≥5), grades upward into DevonianMississippian siliciclastic strata of the Endicott Group, and may be part of the EMA. All

of the Devonian carbonate rocks listed in table 12 are unmetamorphosed (CAI 3-4), part

of the PCA or KRA, and nowhere contiguous with the type Baird Group, and most are of

Middle or Late Devonian age. These De Long Mountains strata are similar to Devonian

limestone (map unit Dlk) in the Howard Pass quadrangle that was not included in the

Baird Group (Dover and others, 2004). We follow that precedent here for Devonian

carbonate rocks in the De Long Mountains quadrangle, and suggest that some coeval

carbonate strata in the Noatak quadrangle (table 13, locs. 168, 170, 180-184) should also

be excluded from the Baird Group because of their age, metamorphic grade, and (or)

stratigraphic, structural, and (or) spatial position. However, other collections in the

eastern and southern Noatak quadrangle (table 13, locs. 185-188) come from an outcrop
Red Dog Fossils OF 2/24/06 4:55 PM p. 41

belt contiguous (Mayfield and others, 1988), and perhaps correlative, with the type Baird

Group.

Eight samples from Devonian carbonate rocks herein excluded from the Baird

Group yielded relatively diagnostic conodont collections (fig. 8). The oldest of these

(loc. 26) is latest Emsian-early Eifelian (late Early-early Middle Devonian) and the

youngest (loc. 104) is Famennian (late Late Devonian). Six collections (locs. 11, 28,

101; table 13, locs. 168, 181, 182) indicate ages within the Eifelian, Givetian, and (or)

Frasnian (Middle-early Late Devonian); limestone at localities 181 and 182 may correlate

with limestone of the Nakolik River (map unit Dnl) of Karl and others (1989) in the Baird

Mountains quadrangle. Other samples produced mostly meager faunas with relatively

long ranges; three samples (table 12) were barren. All collections that yielded biofacies

data denote a shallow-water setting, and several faunas imply deposition in or near a

high-energy environment. Lithofacies of tightly age-constrained samples range from

locally fossiliferous carbonate mudstone to dolomitic crinoidal grainstone. Barren and

poorly productive collections come chiefly from limestone rich in peloids, calcispheres,

and (or) micritized clasts, suggesting a very shallow water depositional setting that may

have had restricted circulation. Data are too scarce to infer differences in lithofacies or

biofacies in these rocks on the basis of structural position.

Rocks in the Noatak quadrangle that may correlate with the Baird Group are

partly dolomitic and contain local black chert nodules; they produced mostly longranging faunas with CAI values of 4 to 5.5. The most tightly dated collection (loc. 185)

is of possible Middle Devonian age; another fauna is Late Silurian-Middle Devonian. No

detailed lithofacies or biofacies data are available from these rocks.
Red Dog Fossils OF 2/24/06 4:55 PM p. 42

THERMAL DATA

Color changes in conodonts provide data on the thermal history of the rocks that

contain them (Epstein et al., 1977). CAI values from the Lisburne Group in the Red Dog

area are mostly 2.5-3.5 (tables 1-8), indicating temperatures of at least 100-200°C (Watts

et al., 1994). Temperature ranges for CAI values were determined from plots of

experimental data of Epstein et al. (1977); a CAI value of 3 indicates a temperature range

of 120-190°C. CAI temperatures can be equated to burial depths for a given geothermal

gradient; for example, in the Appalachian basin, overburdens of ~3,600-5,500 m

produced CAI values of 3 (Harris et al., 1978). Total stratigraphic thickness of the

Pennsylvanian through Lower Cretaceous section overlying Mississippian strata in the

Red Dog area was estimated as generally less than 1,500 m (Mayfield et al., 1988). Thus,

stratigraphic overburden under normal geothermal gradients (such as that of the

Appalachian basin) is not great enough to account for most Lisburne CAI values in the

western Brooks Range.

CAI values in Carboniferous and older rocks in the Red Dog area probably reflect

tectonic burial and (or) an elevated geothermal gradient. Harris and others (1987)

interpreted CAI values in the western parts of the Misheguk Mountain and Baird

Mountains quadrangles as related to tectonic burial rather than prethrust burial

metamorphism because CAI values in coeval rocks in these areas increase downward

through the stack of thrust sheets. CAI values from the Red Dog area show no such

simple patterns, however, and are not consistently higher in lower thrust sheets. Instead,

CAI values in Carboniferous and Devonian rocks from the Endicott Mountains, Picnic
Red Dog Fossils OF 2/24/06 4:55 PM p. 43

Creek, and Kelly River allochthons in the De Long Mountains quadrangle are essentially

identical; 90 percent of ~150 CAI values from these strata in all three allochthons are 2.5-

4, and more than 80 percent are 2.5 to 3.5 (tables 1-8, 11, 12). Igneous activity appears to

have produced some anomalously high CAIs in parts of the Howard Pass area (Dover and

others, 2004). It is possible that elevated CAI values in the Lisburne Group of the Red

Dog area reflect, at least in part, regional increases in heat flow related to extensional

tectonics, local volcanism, and/or mineralization.

CAI values from Carboniferous and Devonian strata in the Noatak quadrangle

show a greater range (from 1 to 5.5) than do values from coeval rocks in the De Long

Mountains quadrangle, but the Noatak CAI values also are not uniformly higher in lower

allochthons (table 13; table 6, locs. 159, 160; table 7, locs. 159, 167; table 8, loc. 172;

table 11, locs. 159, 175, 177, 178). For example, both low (1-2.5) and high (4-5) CAI

values occur in thrust sheets in the Noatak quadrangle interpreted by Mayfield and others

(1987, 1988) as representing low (EMA) and high (NRA) structural levels (table 13, locs.

163, 173, 184; table 6, loc. 159). Conodont values in the Noatak quadrangle do appear to

reflect a rough geographic gradient. CAI values from all samples southeast of a

southwest-northeast trending line that extends from Ipiavik Lagoon to Kikmiksot and

Sivukat Mountains (map 5; samples from EMA, EMA? and NRA) are 4-5.5, whereas

values northwest of this line are 1-3 (samples from EMA, PCA, KRA, NRA), and most

values northwest of the Wulik River are 1-2. Data from the De Long Mountains

quadrangle suggest a comparable pattern in that the lowest CAI values (1.5, 2, 2-2.5)

occur chiefly in the northernmost and far west parts of the quadrangle (e.g., map 1; table

1, locs. 91, 92; table 3, loc. 103; table 6, locs. 2, 3, 94, 116; table 7, loc. 9). A similar
Red Dog Fossils OF 2/24/06 4:55 PM p. 44

increase in CAI values for a given unit at the same structural level from south to northnorthwest was seen in CAI values from the Howard Pass quadrangle (Dover and others,

2004).

ACKNOWLEDGMENTS

Our work at Red Dog was part of a cooperative research project between Teck

Cominco American Inc. and the U.S. Geological Survey (1998-2001); additional studies

in the Red Dog area were carried out as part of the U.S. Geological Survey North Alaska

Fluid Flow project (2002-2004). We thank all of the Teck Cominco staff that

participated in the joint project, particularly Jeff Clark, Scott Jennings, Adrian King, Tom

Krolak, and John Robinson, and our U.S. Geological colleagues, especially Karen Kelley,

Dave Leach, and John Slack, for useful discussions and logistic support. We also thank

John Kelley and his co-workers Kevin Evans, Jeanine Schmidt, and Kirk Sherwood for

providing us with field notes, maps, and information about the samples they collected.

Nora Shew and Daniel Grunwald deftly handled the GIS needs of the project.

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Dumoulin, J.A., Harris, A.G., Blome, C.D., and Young, L.E., 2004, Depositional settings,

correlation, and age of Carboniferous rocks in the western Brooks Range, Alaska: Economic

Geology, v. 99, p. 1355-1384.
Red Dog Fossils OF 2/24/06 4:55 PM p. 47

Dumoulin, J.A., Harris, A.G., and Schmidt, J.M., 1993, Deep-water lithofacies and conodont

faunas of the Lisburne Group, western Brooks Range, Alaska, in Dusel-Bacon, C., and Till,

A.B., eds., Geologic Studies in Alaska by the U.S. Geological Survey during 1992: U.S.

Geological Survey Bulletin 2068, p. 12-30.

Dutro, J.T., Jr., Blodgett, R,B., and Mull, C.G., 1994, Cyrtospirifer from Upper Devonian rocks

of the Endicott Group, west-central Brooks Range, Alaska: in Till, A.B., and Moore, T.E., eds.,

Geologic Studies in Alaska by the U.S. Geological Survey, 1993: U.S. Geological Survey

Bulletin 2107, p. 133-142.

Ellersieck, I., Curtis, S.M., Mayfield, C.F., and Tailleur, I.L., 1984, Reconnaissance geologic map

of south-central Misheguk Mountain quadrangle, Alaska: U.S. Geological Survey

Miscellaneous Investigations Series Map I-1504, 2 sheets, scale 1:63,360.

Ellersieck, I., Curtis, S.M., Mayfield, C.F., and Tailleur, I.L., 1990, Reconnaissance

geologic map of the De Long Mountains A-2 and B-2 quadrangles and part of the C-2

quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map

I-1931, 2 sheets, scale 1:63,360.

Epstein, A.G., Epstein, J.B., and Harris, L.D., 1977, Conodont color alteration—an index to

organic metamorphism: U.S. Geological Survey Professional Paper 995, 27 p.

Gradstein, F.M., Ogg, J.G., and 37 others, 2004, A Geologic Time Scale 2004: Cambridge,

Cambridge University Press, 589 p.

Harris, A.G., Harris, L.D., and Epstein, J.B., 1978, CAI and gas data from Paleozoic rocks in the

Appalachian basin: maps for assessing hydrocarbon potential and thermal maturity (conodont

color alteration isograds and overburden isopachs): U.S. Geological Survey Miscellaneous

Investigations Series Map I-917-B, 4 sheets, scale 1:2,500,000.
Red Dog Fossils OF 2/24/06 4:55 PM p. 48

Harris, A.G., Lane, H.R., Tailleur, I.L., and Ellersieck, I., 1987, Conodont thermal maturation

patterns in Paleozoic and Triassic rocks, northern Alaska—Geologic and exploration

implications, in Tailleur, I.L., and Weimer, Paul, eds., Alaskan North Slope Geology:

Bakersfield, Calif., Pacific Section, Society of Economic Paleontologists and Mineralogists,

Book 50, p. 181-194.

Holdsworth, B.K., and Murchey, B.L., 1988, Paleozoic radiolarian biostratigraphy of the northern

Brooks Range, Alaska, in Gryc, G., ed, Geology and Exploration of the National Petroleum

Reserve in Alaska, 1974-1982: U.S. Geological Survey Professional Paper 1399, p. 777-792.

Ishiga, Hiroaki, 1986, Late Carboniferous and Permian radiolarian biostratigraphy of southwest

Japan: Journal of Geosciences, Osaka City University, v. 29, p. 89-100.

Karl, S.M., Dumoulin, J.A., Ellersieck, I., Harris, A.G., and Schmidt, J.M., 1989, Preliminary

geologic map of the Baird Mountains and part of the Selawik quadrangles, Alaska: U.S.

Geological Survey Open-File Report 89-551, 65 p., 1 pl. scale:1:250,000.

Kelley, K.D., Dumoulin, J.A., and Jennings, Scott, 2004, The Anarraaq Zn-Pb-Ag and barite

deposit, northern Alaska; Evidence for replacement of carbonate by barite and sulfides:

Economic Geology, v. 99, p.

Mayfield, C.F., Curtis, S.M., Ellersieck, I., and Tailleur, I.L., 1984, Reconnaissance geologic map

of southeastern Misheguk Mountain quadrangle, Alaska: U.S. Geological Survey

Miscellaneous Investigations Map I-1503, 2 sheets, scale 1:63,360.

Mayfield, C.F., Curtis, S.M., Ellersieck, I., and Tailleur, I.L., 1990, Reconnaissance geologic map

of the De Long Mountains A-3 and B-3 quadrangles and parts of the A-4 and B-4 quadrangles,

Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-1929, 2 sheets,

scale 1:63,360.
Red Dog Fossils OF 2/24/06 4:55 PM p. 49

Mayfield, C.F., Ellersieck, I., and Tailleur, I.L., 1987, Reconnaissance geologic map of the

Noatak C-5, D-5, D-6, and D-7 quadrangles, Alaska: U.S. Geological Survey Miscellaneous

Investigations Series Map I-1814, 1 sheet, scale 1:63,360.

Mayfield, C.F., Tailleur, I.L., and Ellersieck, I., 1988, Stratigraphy, structure, and palinspastic

synthesis of the western Brooks Range, northwestern Alaska, in Gryc, G., ed., Geology and

exploration of the National Petroleum Reserve in Alaska, 1974-1982: U.S. Geological Survey

Professional Paper 1399, p. 143-186.

Moore, D.W., Young, L.E., Modene, J.S., and Plahuta, J.T., 1986, Geologic setting and genesis of

the Red Dog Zinc-Lead-Silver Deposit, western Brooks Range, Alaska: Economic Geology, v.

81, p. 1696-1727.

Mull, C.G., Crowder, R.K., Adams, K.E., Siok, J.P., Bodnar, D.A., Harris, E.E., Alexander, R.R.,

and Solie, D.N., 1987, Stratigraphy and structural setting of the Picnic Creek allochthon, Killik

River quadrangle, central Brooks Range, Alaska, in Tailleur I.L., and Weimer, P., eds.,

Alaskan North Slope geology: Society of Economic Paleontologists and Mineralogists, Pacific

Section, and Alaska Geological Society, Book 50, p. 650-662.

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biostratigraphy and lithostratigraphy of the western Endicott Mountains, Brooks Range,

Alaska, in Dumoulin, J.A., and Gray, J.E., eds., Geological studies in Alaska by the U.S.

Geological Survey, 1995: U.S. Geological Survey Prof. Paper 1574, p. 221-242.

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and Mesozoic stratigraphic units, central and western Brooks Range, Alaska: American

Association of Petroleum Geologists Bulletin, v. 66, p. 348-362.
Red Dog Fossils OF 2/24/06 4:55 PM p. 50

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Havallah sequence near Battle Mountain, Nevada: implications for the paleogeography and

structural evolution of the western margin of North America, in Harwood, D.S., and Miller,

M.M., eds, Paleozoic and early Mesozoic paleogeographic relations: Sierra Nevada, Klamath

Mountains, and related terranes: Geological Society of America Special Paper 255, p. 137-155.

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facies, radiolarians, and conodonts in the Mississippian to Jurassic siliceous rocks of the

northern Brooks Range, Alaska, in Gryc, G., ed., Geology and exploration of the National

Petroleum Reserve in Alaska, 1974-1982: U.S. Geological Survey Professional Paper 1399, p.

697-724.

Pessagno, E.A., Jr., Finch, J.W., and Abbott, P.L., 1979, Upper Triassic Radiolaria from the San

Hipolito Formation, Baja California: Micropaleontology, v. 25, no. 2, p. 160-197.

Purnell, M.A. and von Bitter, P.H., 1992, Vogelgnathus Norby and Rexroad (Conodonta): new

species from the lower Carboniferous of Atlantic Canada and northern England: Journal of

Paleontology, v. 66, no. 2, p. 311-331.

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Long Mountains, northern Alaska: American Association of Petroleum Geologists Bulletin, v.

45, p. 585-593.

Slack, J.F., Dumoulin, J.A., Schmidt, J.M., Young, L.E., and Rombach, C.S., 2004, Paleozoic

sedimentary rocks in the Red Dog Zn-Pb-Ag district and vicinity, western Brooks Range,

Alaska: Provenance, deposition, and metallogenic significance: Economic Geology, v. 99, p.

1385-1414.
Red Dog Fossils OF 2/24/06 4:55 PM p. 51

Watts, K.F., Harris, A.G., Carlson, R.C., Eckstein, M.K., Gruzlovic, P.D., Imm, T.A., Krumhardt,

A.P., Lasota, D.K., Morgan, S.K., Enos, Paul, Goldstein, R.H., Dumoulin, J.A., and Mamet,

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Range allochthon, western Brooks Range, Alaska: Alaska Division of Geological and

Geophysical Surveys Report of Investigations 92-4, 19 p.

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Alaska: Economic Geology, v. 99, p. 1281-1306.
Red Dog Fossils OF 2/23/06 5:23 PM p. 1

FIGURE CAPTIONS

Figure 1. Distribution of the Lisburne Group (stippled) in northern Alaska and location of

quadrangles and localities mentioned in text (from Dumoulin and others, 2004). PR=Port Road.

SR=Spiny Ridge.

Figure 2. Generalized stratigraphic column for the Endicott Mountains allochthon in the western

Brooks Range showing principal Paleozoic and Mesozoic formations. Note: in some allochthons,

the Utukok Formation directly overlies Devonian carbonate rocks. Unit thicknesses are

schematic. Modified from Young (2004).

Figure 3. Structural hierarchy for allochthons and plates in the Red Dog area, based

mainly on Young (2004).

Figure 4. Depositional setting, fossil control, and stratigraphic context of Lisburne Group

successions in the Red Dog area. Only fossil groups that most narrowly restrict the age

of the collection or unit are listed. Data sources: Curtis and others. (1984, 1990),

Dumoulin and Harris (1992), Ellersieck and others (1990), Mayfield and others (1990),

this paper. Absolute ages are from Gradstein and others (2004). Amph.=Amphitheater

plate, IR=Ipnavik River allochthon, Nach. Pass=Nachralik Pass plate, SD=S. anchoralisD. latus conodont zone, Wolv.=Wolverine Creek plate,;11, 12, and 15-18 are Mamet

foraminifer zones.

Figure 5. Age range of most biostratigraphically useful conodont and radiolarian collections from

deep-water facies of the Lisburne Group; data from tables 1-5, 14 of this report. Locations shown

on maps (sheets 1 and 2). Absolute ages are from Gradstein and others (2004). Ik.=Ikalukrok

unit, Key Ck.=Key Creek plate, Kiv.=Kivalina unit, Kuna=Kuna Formation, LG=Lisburne Group,

Nach. Pass=Nachralik Pass plate, Wolv.=Wolverine Creek plate. *, range of older, redeposited
Red Dog Fossils OF 2/23/06 5:23 PM p. 2

conodonts in samples from locs. 35, 92, and 128 (sample 3). C, R indicates age is based on

combined constraints from conodonts and radiolarians.

Figure 6. Age range of most biostratigraphically useful conodont collections from mainly

shallow-water facies of the Lisburne Group (Kogruk and Utukok Formations and related strata)

and Kayak Shale; data from tables 6-8, 9, 11, 13 of this report. Absolute ages are from Gradstein

and others (2004). Dashed part of bar indicates age range less likely based on overall assemblage

in this collection or other collections from this unit. A=Amphitheatre plate, Am.=Amaruk plate,

C=Chimney plate, E=Eli plate, K=Kelly plate, KC=Key Creek plate, PC=Picnic Creek

allochthon, U=plate uncertain, Wolv.=Wolverine Creek plate, WP=Wulik Peaks plate.

Figure 7. Age range of most biostratigraphically useful radiolarian and conodont collections from

the Etivluk Group and Nuka Formation; data from tables 9, 10, 13, and 14 of this report. Dashed

part of bar indicates age range less likely based on overall assemblage in this collection.

b=Pantanellium silberlingi subzone of Betraccium deweveri radiolarian zone, c=Capnodoce

radiolarian zone, ,KC=Key Creek plate, KR=Kelly River allochthon, PC=Picnic Creek

allochthon, RD=Red Dog plate, U=plate uncertain, W=Wulik plate, Wolv.=Wolverine Creek

plate, WP=Wulik Peaks plate, *, range of older, redeposited conodonts in samples from loc. 16.

Figure 8. Age range of most biostratigraphically useful conodont collections from Devonian

carbonate rocks; data from tables 12 and 13 of this report. See text for discussion of stratigraphic

nomenclature. EM=Endicott Mountains allochthon, KR=Kelly River allochthon, PC=Picnic

Creek allochthon, U=allochthon uncertain.

STRATIGRAPHY

 Kanayut Conglomerate

(meandering and braided streams)

Noatak Sandstone

 (shallow marine)

 Hunt Fork Shale

(shallow to deep marine)

Endicott

 Group

Lisburne

 Group

Kayak Shale 

(shallow marine)

Etivluk

Group

DEVONIAN

 MISSISSIPPIAN MISSISSIPPIAN

PENNSYLVANIAN

PERMIAN

 TRIASSIC

 JURASSIC

CRETACEOUS

 PERIOD

 Kuna Fm.

(deep marine)

Kogruk Fm. (shallow marine)

Utukok Fm. (shallow marine)

Siksikpuk Formation (mid-shelf or deeper)

Otuk Formation (mid-outer shelf )

Okpikruak Formation (flysch)

 Unnamed carbonate rocks

(shallow marine) Base not exposed

?

Figure 2
Allochthon

Pass

Plate

Nuka 

Ridge

Ipnavik River

Kelly

River

Picnic

Creek

Endicott

Mountains

Bogie

Bastille

Nachralik

Eli

Wulik PeaksKelly

Chimney-

 Amphitheatre

Amaruk

Wulik

Key Creek

Red Dog

Wolverine Creek

Figure 3
Endicott Mountains

Wolv. Red Key Creek

Port Rd Wulik Amaruk Wulik Amph. Kelly Eli Nach.

Kelly River IR

Plate

Allochthon

Age (Ma)

System

Series

Stage

Dog Peaks Pass

Picnic

Creek

312

318

326

345

359

Pennsylvanian (part) Mississippian Devonian (part)

Middle (part) Lower Upper

Chesterian Morrowan Atokan Meramecian

Lower

Osagean Kinderhookian

Upper (part)

Famennian

Utukok Fm.

Utukok Fm.

C

C Co

C

C

F

F

F

F

F

Co C Co

R

C,F,A C

Br

C

F

F

C,F B

C C

C C

C C

C C C C

C

C,R

C,R

R R R

Co,F C

C

C

C

C

C

Kayak Sh.

Kogruk Fm.

Siksikpuk Fm.Siksikpuk Fm.Siksikpuk Fm.Siksikpuk Fm.Siksikpuk Fm.

Ikalukrok unit

Kuna Fm.

Kogruk Fm. Utukok Fm.

Kayak Sh.Kayak Sh.Kayak Sh.Kayak Sh.Kayak Sh.

Utukok Fm.

Micritic

Utukok Fm.

Kogruk Fm.

Kogruk Fm.

Siksikpuk Fm.

Kogruk Fm. Utukok Fm.

Unnamed limestone

Eli Limestone

Kayak Sh.

Imnaitchiak ChertSiksikpuk Fm.

or

limestone unit

Kanayut Conglomerate

Kanayut Conglomerate

Kivalina unit

]

]

]

]

]

]

]

18

17

16

15

12

11

SD

Inner and/or middle platform

Outer platform or deeper

Slope and/or basin

Uncertain

Fossil Control

Radiolarian

Foraminifer

Algae Coral

Conodont

Bryozoan

Brachiopod

or zone

Age known to stage

Age known to series

or two-stage interval

A

R

F

Co

C

Br

B

? ? ? ?

? ?

Lisburne Group Depositional Settings

C

Kogruk Fm.

C C C

Figure 4
STAGE

FORAM.

ZONES

CHESTERIAN 

MECIAN OSAGEAN 

HOOKIAN

UNZONED

pre7

7

8

9

1011

12

13

14

15

16i

16s

17

18

19

CONODONT

ZONES

Rh. muricatus

C. naviculus

G. bilineatus -

Upper Cavusgnathus

Lower Cavusgnathus

G. homopunctatus -

Upper G. texanus

Po. mehli -

Lower G. texanus

Sc. anchoralis - D. latus

G. typicus Upper

Lower

Si. isoticha -

Upper Si. crenulata

Lower S. crenulata

Si. sandbergi

Si. duplicata

Si. sulcata

A l l o c h t h o n

Endicott Mountains

Wolv.

LG (5) Kiv. (2)

Red Dog

Ik. (1, 14)

Key Ck.

Kuna (3, 14) Lisburne Group (4)

Loc. 120

Loc. 10 Locs. 19, 20

Loc. 35

Loc. 117 (25A)

Locs. 37, 38, 117 (25F)

Loc. 34 (+590 ft) Loc. 34 (lower part)

Loc. 107 (B-F) Locs. 24, 103

Loc. 92

Loc. 128 (3)

Locs. 41 (C, R), 124 Loc. 48

Locs. 47, 123, 139

Loc. 76

Loc. 78

Locs. 137 (4), 138 (1),142

Loc. 85

Loc. 89

?

?

?

LG (5)

Nach. Pass

P i c n i c C r e e k I p n a v i k R i v e r

P l a t e , u n i t ( t a b l e )

Wulik Amaruk

Loc. 4

*******************  

** ************

Loc. 34 (+360 ft)

Rh. primus

************************

Ad. unicornis

Figure 5
C A R B O N I F E R O U S ( PA R T )

MISSISSIPPIAN

TOURNAISIAN VISEAN SERPUKHOVIAN (part)

TOURNAISIAN VISEAN NAMURIAN (part)

EPOCH

EURO.STAGE

N. AM.

STAGE

FORAM.

ZONES

CHESTERIAN MERA- MECIAN OSAGEAN KINDER- HOOKIAN

UNZONED

pre7

7

8

9

10

11

12

13

14

15

16I

16S

17

18

19

CONODONT

ZONES

Rh. muricatus

Ad. unicornis

C. naviculus

G. bilineatus -

Upper Cavusgnathus

Lower Cavusgnathus

G. homopunctatus -

Upper G. texanus

Po. mehli -

Lower G. texanus

Sc. anchoralis - D. latus

G. typicus Upper

Lower

Si. isoticha -

Upper Si. crenulata

Lower Si. crenulata

Si. sandbergi

Si. duplicata

Si. sulcata

A l l o c h t h o n

Endicott Mountains

Wolv. (6, 7) KC (6-8, 1,13) Am (11)

PC

C (6) A (6)

Kelly River Uncertain Locs. 18, 25 Loc. 116 Loc. 102 Loc. 52

Loc. 94

Loc. 21

Loc. 73 (25A) Locs. 63, 64, 73

Loc. 147 Loc. 45

?

?

?

345.3

+ 2.1

P l a t e ( t a b l e s )

WP (6, 7) K (6, 7, 13)

Loc. 167

Loc. 62 (part) Loc. 93

Loc. 166

Loc. 9

Loc. 62

Loc. 75

Loc. 42

Loc. 148

Loc. 73 (25B)

Loc. 121

Loc. 160

Locs. 158,175,177

Locs. 31, 159 (3) Locs. 174,178

Loc. 172 (23B)

Loc. 15

Loc. 22

Locs. 32, 46

Locs. 6, 40

Loc. 8

Locs. 69, 162

E (7,13) U (6,7,9)

Rh. primus

AGE

PERIOD

(Ma)

Stratigraphy and setting

Kogruk Fm., 

Kogruk Fm., 

Utukok Fm.

Utukok Fm. (?)

Kayak Shale

outer platform or deeper 

 shallow platform

326.4

+1.6

359.2

+ 2.5

Figure 6
(part)

b

c

Anisian

Spathian

Smithian

Dinierian

Griesbachian

Lopingian

Guadalupian

Leonardian

Wolfcampian

Virgilian

Missourian

Desmoinesian

Atokan

Morrowan

Chesterian

Mississippian

Meramecian

Upper

Pennsylvanian

Lower Middle Upper Upper Lower

Permian

Upper Middle Lower

Triassic

A l l o c h t h o n

Endicott Mountains PC PC? KR Uncertain Nuka Ridge

Wolv.(14) RD(14) KC(14) W(14) U(9) WP(14) U(9) Bogie (9,10,13)

Period

Series

Stage

Rhaetian

Norian

Carnian

Ladinian

Loc. 126

Loc. 152 Loc. 66

Loc. 33

Loc. 35 (19A)

Loc. 35 (19B)

Loc. 36

Loc. 5 (4E)

Loc. 5 (4F)

Loc. 62 (part)

Loc. 16

Locs. 163,165

Loc. 62 (part)

Locs. 136, 150

Locs. 72,107(O-S)

Loc. 107(T)

Loc. 61

Plate (table)

Middle

* * * * * * *

Stratigraphic Unit

Otuk Formation

Upper subunit

Middle subunit

Lower subunit (?)

Siksikpuk Formation

Middle subunit (?)

Lower subunit

Nuka Formation

Figure 7
Loc. 104

Loc. 181

Loc. 168

Loc. 182

Loc. 11

Loc. 28

Loc. 101

Loc. 185

Loc. 26

EM (13) PC (12) KR (12) U (13)

A L L O C H T H O N

Si. praesulcata expansa

Pa. gracilis expansa

Pa. perlobata postera

Pa. rugosa trachytera

Pa. m. marginifera

Pa. rhomboidea

Pa. crepida

Pa. triangularis

Pa. linguiformis

Pa. rhenana

Pa. jamieae

Pa. hassi

Pa. punctata

Pa. transitans

M. falsiovalis

K. disparilis

S. hermanni - P. cristatus

Po. varcus

Po. x. ensensis T.k. kockelianus T.k. australis

Po. c. costatus

Po. c. partitus

Po. c. patulus

Po. serotinus

Po. inversus

EMSIAN

(part)

EIFELIAN GIVETIAN FRASNIAN FAMENNIAN

SERIES

STAGE

SYSTEM DEVONIAN (part)

MIDDLE UPPER LOWER

C O N O D O N T Z O N E S

Baird Group(?)

Limestone of Nakolik River

Unnamed

Carbonate rocks excluded from 

Stratigraphic unit

Baird Group

Figure 8
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

4

EMA (Red Dog

plate)

De Long Mtns.

B-3

68°22'12"/

163°22'00"

1 juvenile Pa element Bispathodus utahensis

Sandberg and Gutschick

1 juvenile Pa element Gnathodus sp. indet.

1 S element bar fragment of Scaliognathus

anchoralis Branson and Mehl or its ancestor

22 indet. bar, blade, and platform fragments

CAI=2.5-3

[79EK189C-2; 27555-PC]

late Early Mississippian

(early-middle Osagean; G.

typicus Zone-Sc. anchoralisDo. latus Zone).

Indeterminate;

conodonts indicate a

distal winnow from or

within a slope or basin

depositional setting.

Sample from a lens of light-gray-weathering limestone

within an interval of shaly limestone.

Fossil loc. 26, Mayfield and others (1990).

Loc. 7 (app. 1) of Dumoulin and others (2004).

41

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°14'22"/

162°54'33.8"

1 mid Pa element fragment Gnathodus texanus

Roundy?

1 juvenile Pa element Gnathodus sp. indet. of postKinderhookian morphotype

2 Sc elements Gnathodus? sp. indet.

24 indet. bar, blade, and platform fragments

CAI=~3 (most conodonts covered with organic

matter or very small)

[98AD10A; 33416-PC]

late Early-middle Late

Mississippian (late Osageanearly Chesterian).

Constraints from

radiolarians at this locality

restrict age to early

Chesterian.

Indeterminate (too few

conodonts); conodonts

present indicate

postmortem transport

within or from a

normal-marine

depositional setting.

Sample from chert-rich upper part of Ikalukrok unit;

see table 14 for radiolarian sample from this locality.

1 m of medium-brown-gray-weathering, dark-gray,

fetid, cross-laminated(?), very fine grained limestone

in 0.25 to 1 cm thick beds, interbedded with thinbedded black siliceous mudstone. Thin section is

packed, calcareous radiolarite with minor barite; test

structure of some radiolarians quite well-preserved.

Heavy-mineral concentrate includes muscovitic and

(or) chloritic schist fragments.

8.3 kg of rock was processed.

Loc. 3 (fig. 2) of Dumoulin and others (2004).

1 Pa element fragment Gnathodus texanus Roundy

1 unassigned Pb element

9 indet. bar, blade, and platform fragments

CAI=4

[8-16-83C; 29229-PC]

late Early-middle Late

Mississippian (late Osageanearly Chesterian).

Indeterminate (too few

conodonts).

Lower part of chert-rich interval, upper Ikalukrok unit.

Stratigraphic level probably close to that of

98AD10A.

 Massive-bedded and laminated lenses of chert,

limestone, and dolostone. Sampled dark-gray, very

fine grained limestone that weathers moderate

yellowish brown. Thin section is packed, calcareous

radiolarite with minor barite; test structure of some

radiolarians very well preserved.

5.0 kg of rock was processed.

Sample collected by A.G. Harris.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

47

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°13'10.3"/

163°3'20"

(location

approximate on

long line of

traverse)

19 Pa elements Bispathodus utahensis Sandberg

and Gutschick

1 P element Eotaphrus sp. indet.

1 juvenile Pa element Polygnathus communis

Branson and Mehl

3 S element fragments Scaliognathus anchoralis

Branson and Mehl

Unassigned elements:

 9 Pb (3 morphotypes), 2 M (2 morphotypes), 1 Sb

and 6 Sc (4 morphotypes)

148 indet. bar, blade, and platform fragments

CAI=2.5

[KE98-17; 33503-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralis-Do.

latus Zone).

Indeterminate (too few

generically identifiable

conodonts.

Off-platform conodont

species and an

abundance of small

delicate conodont

fragments occurring

with radiolarians and

sponge spicules

indicate a slope or

basin depositional

setting.

Concretion, ~20x40 cm, in Ikalukrok unit. Browngray-weathering black lime mudstone. Thin section

is calcareous radiolarite with lesser calcareous

sponge spicules; some radiolarians filled with

chalcedony.

Heavy-mineral concentrate includes minor sponge

spicules, pyritized and calcitized radiolarians, and

muscovite.

6.42 kg of rock was processed.

48

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°12'45.6"/

163°04'17"

(location

approximate on

long line of

traverse)

1 Pa element fragment Bispathodus utahensis

Sandberg and Gutschick

1 Pa element (mostly complete) Gnathodus

cuneiformis Mehl and Thomas

1 Pa element Gnathodus pseudosemiglaber

Thompson and Fellows

1 M element Kladognathus sp. indet.

1 Pa element Polygnathus sp. indet.

63 indet. bar, blade, and platform fragments

CAI=2.5

[KE98-19A; 33504-PC]

middle late Early

Mississippian (late middle

Osagean; upper half Sc.

anchoralis-Do. latus Zone).

Mixed biofacies;

postmortem transport

from outer shelf or

slope depositional

setting.

Turbidite in Ikalukrok unit.

Medium-gray to medium-dark-gray, fine-grained

limestone. Thin section is sandstone made up of

quartz, crinoid ossicles, noncarbonate mud, and

phosphate clasts.

6.1 kg of rock was processed.

11 juvenile Pa elements Gnathodus spp. indet. [pl.

1, fig. 8]

2 Sb-Sc elements Kladognathus sp.

Unassigned elements:

 1 M and 1 Sc

51 indet. bar, blade, and platform fragments

CAI=2

[KE98-19B; 33644-PC]

Mississippian, but not very

early Early Mississippian

(late KinderhookianChesterian).

Indeterminate (too few

conodonts); conodonts

present indicate a

postmortem winnow

into off-shelf or deeper

water depositional

setting.

Concretion, 10x10x20 cm, in Ikalukrok unit.

Partly silicified carbonate, medium-dark-gray to

medium-gray, weathers brown. Thin section is

calcareous radiolarite. Radiolarian test structure

locally well preserved; some tests partly pyritized.

Heavy-mineral concentrate includes minor pyritized

sponge spicules and phosphatic brachiopod

fragments.

2.76 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

49

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°12'12"/

163°03'48"

Barren

[KE98-20A]

Limestone turbidite in Ikalukruk unit, ~21 ft above

base of 310-ft-thick measured section; section may

be faulted and is not stratigraphically complete.

Yellow-brown-weathering, medium-dark-gray, finegrained limestone bed (~1 ft thick) in black shale.

Thin section is skeletal packstone; bioclasts mainly

calcareous spicules and rare calcareous radiolarians

in a matrix of noncarbonate mud with rare quartz

silt.

Heavy-mineral concentrate includes rare phosphatic

brachiopod fragments.

3.0 kg of rock was processed.

15 Pa elements (mainly fragments) Bispathodus

utahensis Sandberg and Gutschick

2 juvenile to subadult Pa element fragments

Gnathodus pseudosemiglaber Thompson and

Fellows

1 unassigned M element

74 indet. bar, blade, and platform fragments

CAI=3

[KE98-20C; 33505-PC]

middle late Early-early Late

Mississippian (middle Sc.

anchoralis-Do. latus Zone

through Meramecian).

Postmortem transport

(winnow) from the

bispathodid biofacies,

suggesting an outer

shelf or deeper water

depositional setting.

Limestone turbidite in Ikalukruk unit, ~123 ft above

base of measured section.

Brownish-gray limestone bed (~1 ft thick) underlain

and overlain by black shale and siliceous mudstone.

Thin section is fine-grained skeletal grainstone;

bioclasts mostly crinoid ossicles, lesser ostracodes,

calcareous and siliceous spicules, productid spines,

and bryozoan fragments.

2.1 kg of rock was processed.

50

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°11'48"/

163°03'00"

1 juvenile Pa element Bispathodus utahensis

Sandberg and Gutschick

3 Pa element fragments Gnathodus texanus Roundy

1 juvenile Pa element fragment Gnathodus sp.

indet.

1 Sc element fragment Kladognathus sp. indet.

100 indet. bar, blade, and platform fragments

CAI=3-3.5

[8-16-83E; 29231-PC]

very late Early-middle Late

Mississippian (late Osageanearly Chesterian, but

probably no younger than

Meramecian; P. mehli-lower

G. texanus Zone through at

least Lower Cavusgnathus

Zone)

Indeterminate (too few

conodonts). Because

virtually all conodonts

are relatively small

fragments, this

collection has

undergone

considerable

postmortem transport.

Cycles of sandy, thick-bedded fine-grained limestone

grading up into very dark gray to black argillaceous

limestone, and, finally, to carbonaceous shale.

Collection from near top of turbiditic coarse bed of

medium-dark-gray, medium-gray- to grayishorange-weathering, very fine grained silty limestone.

Thin section is fine- to coarse-grained sandstone;

clasts mostly calcareous and (or) pyritized and

include abundant (>20%) radiolarians and lesser

spicules. Noncarbonate grains ~20%, mostly quartz,

minor white mica, and phosphate.

6.0 kg of rock was processed.

Sample collected by A.G. Harris.

Loc. 10 (fig. 2) of Dumoulin and others (2004).
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

76

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'53.8"/

163°05'52.6"

3 Pa elements Cavusgnathus unicornis Youngquist

and Miller [pl. 1, fig. 6]

Gnathodus texanus Roundy (juveniles and adults):

 9 Pa and 2 M elements [pl. 1, fig. 5]

6 element fragments Idioprioniodus sp. indet.

235 indet. bar, blade, and platform fragments

CAI=3.5-4

[99AD11BB; 33479-PC]

middle late Mississippian

(late Meramecian-early,

probably earliest Chesterian)

Indeterminate (too few

generically identifiable

conodonts); likely

postmortem transport

from or within the

gnathodid biofacies

(slope or toe of slope

depositional setting).

Interval of limestone (turbidites?) >10 m thick; sample

from middle of good outcrop. Massive, mediumgray- (slightly brownish) weathering, black, fine- to

medium-crystalline limestone that has parallel

lamination and is fetid. Thin section is anhedral

calcite crystal mosaic with rare calcite-replaced

radiolarians.

L. Young suggests this limestone interval is ~40 m

thick. Limestone float found ~100 ft uphill supports

idea of a thick carbonate section here, but main

carbonate exposure is 10 m thick.

+7.5 kg of rock was processed.

Barren

[99AD11F]

Sample from limestone bed just below base of the

layer sampled in 11BB; a grayish shale break

separates the two carbonate intervals.

1-m-thick interval of medium-gray- (slightly brownish)

weathering, grayish-black, medium crystalline

limestone in 2 to 10 cm thick uneven beds. Thin

section is calcareous radiolarite.

Heavy-mineral concentrate is chiefly composite rock

fragments of recrystallized barite(?), with organic

matter, and trace sphalerite(?).

+9.0 kg of rock was processed.

77

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°03'37.3"/

163°08'2.6"

1 juvenile Pa element Lochriea sp.—L. cf. L.

commutata (Branson and Mehl)

 1 indet. blade fragment

CAI=2.5-3

[79EK15B-2; 27505-PC]

Late Mississippian Indeterminate (too few

conodonts).

Limestone bed about 20 m below top of Kuna

Formation (Ikalukrok unit).

4 kg of rock was processed.

Fossil loc. 16, Ellersieck and others (1990).
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

91

Uncertain;

EMA (Red Dog

plate) or PCA

De Long Mtns.

C-1

68°30'28"/

162°14'12.2"

35 Pa elements Bispathodus utahensis Sandberg

and Gutschick (most are large and incomplete)

3 incomplete Pa elements Cavusgnathus sp.

20 Pa (mostly incomplete) elements Gnathodus

pseudosemiglaber Thompson and Fellows

1 Pa element Gnathodus texanus Roundy

5 Idioprioniodus sp. indet. element fragments

1 Sa element fragment Kladognathus sp.

3 Pa elements (2 posterior platform fragments and

1 complete Pa (juveniles and 1 adult )

Mestognathus beckmanni Bischoff or M.

praebeckmanni von Bitter, Sandberg, and Orchard

1 Pa element fragment Pseudopolygnathus sp.

indet.

Unassigned elements:

 1 Pb, 5 M (4 morphotypes), and 1 Sa

754 indet. bar, blade, and platform fragmen s

CAI=2.0-2.5

[03AD28A; 33759-PC]

late Early-middle Late

Mississippian (late middle

Osagean-very early

Chesterian; Po. mehli-Lower

Gn. texanus Zone into

earliest Chesterian).

Conodonts are

hydraulically

transported and include

normal-marine shelf

and slope facies

elements as well as

very shallow water

genus Mestognathus.

Kuna Formation (Ikalukrok unit?); sample taken ~6 m

below top of partial section of siliceous mudstone

that is ~16 m thick. Kuna here overlain (apparently

depositionally) by Okpikruak Formation, but contact

is not exposed. Underlying this mudstone section is

black sooty shale (Ikalukrok?), and then rubble of

black siliceous shale and orange-weathering

calcareous siltstone (Kivalina unit?).

Medium- to medium-light-gray (slightly brownish)

limestone turbidite, weathers very pale yellow

brown. Limy interval is ~40 cm thick; underlain and

overlain mostly by black siliceous mudstone and

chert. Limestone in irregular 5- to 10-cm-thick beds,

with black mud chips and small bioclasts. Thin

section is mostly fine-grained calcite with 10-30%

dolomite, 5-10% largely silica-replaced bioclasts

(crinoids, ostracodes, bryozoans, and radiolarians),

5-10% black mud clasts, and minor quartz silt.

Heavy-mineral concentrate is chiefly composite,

slightly carbonaceous, phosphatic carbonate grains,

white to translucent fluorite(?), and rare glauconite,

phosphatic brachiopod fragments and pelmatozoan

ossicles.

10.1 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

(field No.; USGS collection No.)

Age Conodont biofacies and

depositional

environment

Remarks

92

Uncertain;

EMA (Red Dog

plate) or PCA

De Long Mtns.

C-1

68°30'20"/

162°14'9.5"

Bispathodus utahensis Sandberg and Gutschick

 144 (mostly incomplete) Pa and 1 Sb elements

15 complete to incomplete Pa elements

Cavusgnathus unicornis Youngquist and Miller

40 Pa elements (nearly complete to mostly

incomplete) Embsaygnathus asymmetricus

Metcalfe

Idioprioniodus? sp. indet.:

 26 Pa, 12 Pb, 27 M, 1 Sa, 9 Sb, and 4 Sc elements

and 24 bar fragments

Kladognathus sp. indet.:

 1 M, 1 Sa, and 3 Sb-Sc elements

7 subadult Pa elements (all somewhat incomplete)

Mestognathus beckmanni Bischoff

Redeposited Early Mississippian conodonts:

1 Pa element Gnathodus cuneiformis Mehl and

Thomas

3 Pa element fragments Pseudopolygnathus sp.

indet.

1 bar fragment Scaliognathus anchoralis Branson

and Mehl

Unassigned elements:

 7 Pb (6 morphotypes), 1 M, 2 Sc

1202 indet. bar, blade, and platform fragments

CAI=2.0-2.5

[03AD28H; 33760-PC]

middle Late Mississippian

(early late Meramecian).

The occurrence of

Cavusgnathus unicornis

with what is now the largest

single collection of the rare

conodont Embsaygnathus

asymmetricus (known only

from northern England,

Dublin County of eastern

Ireland, and northern

Alaska) restricts the age of

this collection to the early

late Meramecian. In most

known occurrences, E.

asymmetricus occurs with

other shallow-water species

(e.g., mestognathids and

cavusgnathids) in the coarser

layers of turbiditic beds.

This collection also contains

relatively rare redeposited

Osagean conodonts. The

most abundant conodont

species in the collection (Bi.

utahensis) could be

indigenous as well as

redeposited.

Hydraulically

redeposited conodonts.

Virtually all specimens

are incomplete and

most are relatively

large (40- to 60-mesh

sieve fraction).

Conodonts are chiefly

surface swimmers (Bi.

utahensis is a globally

widespread eurytopic

species) and shallowwater forms

(mestognathids

occupied one of the

shallowest warm-water

conodont biofacies).

The form species

Geniculatus claviger is

most likely the Pb

element of

Embsaygnathus? sp.

Kuna Formation (Ikalukrok unit?). These rocks could

be part of a structural repeat of the Kuna section

sampled in 03AD28A, but the limy interval here is

thicker and contains thicker, more calcareous beds.

However, the limy beds are turbidites, and thus

could be irregularly distributed. Alternately (less

likely), this could be an interval of Lisburne Group

of the PCA in structural contact with Kuna of the

EMA.

Thirty-cm-thick bed of coarse-grained skeletal

grainstone/packstone; weathers light brownish gray

to medium light gray (fresh color is very slightly

darker). Contains abundant crinoid ossicles and

brachiopods to 1.5 cm in diameter. Thin section is

pelmatozoan grainstone, with abundant and diverse

bryozoans, brachiopods, and ostracodes, minor

foraminifers, algae, and phosphatic bioclasts, and a

few carbonate clasts (one contains calcareous

spicules, another has calcite-replaced radiolarians).

Heavy-mineral concentrate is chiefly phosphatized and

lesser dolomitized rock fragments, phosphatic and

phosphatized bioclasts (mainly conodonts, minor

phosphatic brachiopod fragments, and rare

phosphatized pelmatozoan ossicles and gastropod

steinkerns), and fluoritic carbonate grains.

10.9 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

123

EMA (Red Dog

plate)

De Long Mtns.

A-3

68°09'45.4"/

163°12'30.7"

2 Pa elements Gnathodus cuneiformis Mehl and

Thomas [pl. 1, fig. 1]

1 Pa element Gnathodus sp. indet.

1 Pa element Eotaphrus? cf. E. bultyncki

(Groessens)

1 Pa element Polygnathus communis Branson and

Mehl

60 indet. bar, blade, and platform fragments

CAI=4

[DDH Su 31 (Su deposit), 1667-1686 ft; 29280-PC]

late Early Mississippian

(middle Osagean; Sc.

anchoralis-Do. latus Zone).

Indeterminate (too few

conodonts); the

diversity indicates

open-marine

conditions.

Sample ~101 ft below conformable(?) contact of

Siksikpuk Formation and Ikalukrok unit and ~12 ft

above mineralized sulfide zone at Su deposit.

Samples lower half of 48-ft-thick interval of

calcareous turbidites with shale interbeds as much as

3 ft thick. See table 2 for Kivalina unit sample from

this drill hole.

8.2 kg of rock was processed.

Sample collected by D. Moore, I.L. Tailleur, and L.E.

Young.

124

EMA (Red Dog

plate)

De Long Mtns.

A-3

68°09'42.6"/

163°11'49.2"

Gnathodus texanus Roundy:

 12 Pa, 4 Pb, 1 M, 1 Sb, and 2 Sc elements [pl. 1,

fig. 7]

1 juvenile Pa element Gnathodus sp. indet.

1 Pa element Rhachistognathus prolixus

Baesemann and Lane?

1 unassigned M element

99 indet. bar, blade, and platform fragments

CAI=3

[DDH Su 16 (Su deposit), 558-577 ft; 29279-PC]

middle Late Mississippian

(early Chesterian).

Gnathodid biofacies:

open marine, likely

slope depositional

setting.

Sample ~109 ft below conformable contact of

Siksikpuk Formation and Ikalukrok unit and ~421 ft

above main mineralized sulfide zone at Su deposit.

Samples several calcareous turbidites from lower

part of ~100-ft-thick interval of interbedded

turbidites and black shale. See table 2 for Kivalina

unit sample from this drill hole.

7.3 kg of rock was processed.

Sample collected by D. Moore, I.L. Tailleur, and L.E.

Young.

125

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°11'20"/

163°06'20"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 922 (slightly west of Wulik deposit),

composite conodont sample 1, 45.5-46.5 and 51.6-

52.6 ft]

Sample ~32 ft below top of carbonate-rich partial

section of Ikalukrok unit that is at least 950 ft thick

and not obviously structurally thickened.

Light-gray to medium-light-gray (outer), mediumdark-gray (inner), medium-grained carbonate that is

laminated to very thin bedded with 0.1 to 2 mm dark

shale partings; some graded beds ≤2 cm thick of

coarser grained carbonate turbidite, medium-lightgray to light-gray (outer) and medium-gray (inner).

Thin section data:

45.5, 53 ft: Calcareous radiolarite; some radiolarians

preserved within calcite concretions 1 to 2 mm in

diameter.

3.92 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

125

EMA (Red Dog

plate)

[cont.]

De Long Mtns.

A-2

68°11'20"/

163°06'20"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 922, composite conodont sample 2, 163-

164.5 ft]

Sample ~150 ft below top of carbonate-rich partial

section of Ikalukrok unit.

Medium-light-gray (outer), medium-dark-gray (inner),

very fine to fine-grained carbonate turbidite with

15% calcite veins and <2% mudstone layers. Thin

section at 164.5 ft is calcareous radiolarite.

Heavy-mineral concentrate includes minor pyritized

triaxon sponge spicules.

1.7 kg of rock was processed.

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 922, composite conodont sample 3, 530-550

ft]

Sample ~517 ft below top of carbonate-rich partial

section of Ikalukrok unit

Very light gray to light-gray (outer), medium-lightgray to light-gray (inner) limestone in 2 mm to 2 cm

layers with mud breaks <1 mm thick.

Thin section data:

538.5 and 545.5 ft: Calcitized radiolarians and

carbonate concretions, 1 to 2 mm in diameter, that

contain one or more radiolarians (some pyritized), in

a matrix of brown, noncarbonate mud.

540.5, 545 ft: Calcareous radiolarite; 540.5 is poorly

preserved and cross-cut by calcite veins; 545

contains lenses of noncarbonate mud.

547: Brown, noncarbonate mud with angular quartz silt

and locally abundant calcitized radiolarians.

8.56 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

128

EMA (Red Dog

plate;

Competition

Creek subplate)

De Long Mtns.

A-2

68°10'03"/

162°58'29"

13 indet. bar and blade fragments

CAI=3

[DDH 807 (Anarraaq deposit), composite conodont

sample 1: 39-47.7 ft; 33491-PC]

Unit known to be

Mississippian in age.

Indeterminate (too few

conodonts).

Sample ~40 ft below top of highest of three structural

repeats of Ikalukrok unit (drill hole begins in

Ikalukrok). Sample is calcareous lithic turbidite ~9 ft

thick, interbedded with siliceous mudstone and

chert. Subplate nomenclature from S. Jennings.

39-47.7 ft: Light- to medium-light-gray (outer) and

medium-dark-gray (inner) calcareous sandstone or

sandy limestone containing very irregular lime mud

rip-up clasts as much as 2 cm long and some

burrows. No grading noted; could be more than one

event amalgamated and homogenized by burrowing.

Thin section data:

40.8 and 42 ft: Lithic turbidites, with quartz, mica,

lithic clasts (mudstone, carbonate, chert, and

calcareous radiolarite), and productid spines (some

replaced by silica) in carbonate matrix.

Heavy-mineral concentrate includes rare tan to white

mica and phosphatized radiolarian steinkerns.

Light-mineral residue includes possible fluorite.

 4.2 kg of rock was processed.

(Competition

Creek subplate)

2 indet. bar and blade fragments

CAI=3.5

[DDH 807, composite conodont sample 2: 166.5-

73.5 and 174-75 ft; 33492-PC]

Unit known to be

Mississippian in age.

Indeterminate (too few

conodonts).

Sample ~167 ft below top of highest of three structural

repeats of Ikalukrok unit (drill hole begins in

Ikalukrok). Sample is calcareous lithic turbidite ~10

ft thick.

166.5-175.0 ft: Carbonate turbidite, graded from

medium to fine sand and silt-size grains; calcareous

sandstone is medium dark gray (outer) and medium

gray and dark gray (inner). Locally calcareous black

mudstone lies above and below turbidite.

Thin section data:

167.5, 169, 171.5 ft: Lithic turbidites, with clasts of

quartz, carbonate, chert, altered feldspar, and crinoid

ossicles in matrix of brown mud and local carbonate

cement.

4.34 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

128

EMA (Red Dog

plate; Gul

subplate)

[cont.]

De Long Mtns.

A-2

68°10'03"/

162°58'29"

13 Pa elements Bispathodus utahensis Sandberg

and Gutschick (including juveniles) [pl. 1, fig. 4]

11 Pa elements Gnathodus cuneiformis Mehl and

Thomas [pl. 1, fig. 2]

1 Pa element Gnathodus delicatus Branson and

Mehl

25 Pa elements Gnathodus texanus Roundy

Gnathodus spp. indet.

 5 Pa (juveniles), 6 M, 1 Sa, and 20 Sc elements

6 Idioprioniodus sp. elements

Kladognathus sp.

 2 M, 1 Sa, and 6 Sc element fragments

5 Pa elements Polygnathus communis Branson and

Mehl

1 Pa element Polygnathus mehli Thompson

2 incomplete Pa elements Polygnathus sp. indet.

7 Pa elements Pseudopolygnathus spp. (juveniles

and incomplete elements)

Redeposited late Kinderhookian and (or) middle

Osagean conodonts:

10 S bar fragments Scaliognathus anchoralis

Branson and Mehl (="Hindeodella" segaformis

Bischoff s.f.)

1 Pa element Protognathodus praedelicatus Lane,

Sandberg, and Ziegler [pl. 1, fig. 3]

Redeposited Kinderhookian conodonts:

4 Pa elements (subadults) Siphonodella sp. indet. of

middle-late Kinderhookian morphotype

Unassigned elements:

 12 Pb (5 morphotypes), 27 M (>4 morphotypes), 3

Sa (2 morphotypes), 6 Sb (3 morphotypes), and 7

Sc (2 morphotypes)

925 indet. bar, blade, and platform fragments

CAI=2.5-3

[DDH 807, composite conodont sample 3: 1282-

1297.3 ft; 33493-PC]

No older than late late Early

Mississippian (no older than

late Osagean, Po. mehliLower G. texanus Zone);

contains redeposited older

Early Mississippian

(Kinderhookian and middle

Osagean) conodonts.

Mixed biofacies;

postmortem transport

within or from the

gnathodid biofacies

suggesting at least a

slope or deeper water

depositional setting.

Fauna includes

redeposited conodonts

of mixed Early

Mississippian ages.

Sample ~72 ft below top of second of three structural

repeats of Ikalukrok unit; this interval of Ikalukrok

is fault-bounded above and below. Sample from

lower part of ~25-ft-thick interval of calcareous

lithic turbidites.

1282-1297.3 ft: Light-gray to medium-light-gray

(outer) and medium-dark-gray (inner) massive sandy

limestone, with fining-upward cycles of medium to

fine sand-sized carbonate, locally cross laminated, in

sets 0.5 to 2 cm thick; stylolites separate many

graded sets. Calcite spar veins <1%.

Thin section data:

1287 ft: Lithic turbidite with 0.5-cm-thick light and

dark layers and abundant radiolarians. Contains

calcite cement and common carbonate clasts; other

clasts include quartz, chert, siltstone, and zircon(?).

1294 ft: Lithic turbidite with uniform texture. Contains

calcite cement and common carbonate clasts; other

clasts include quartz, chlorite, crinoid ossicles, and

productid spines.

1298.7 ft: Mostly noncarbonate clasts in a brown

noncarbonate mud matrix. Clasts include brown

mudstone to 1.4 mm in diameter, quartz, productid

spines, and rare crinoid ossicles.

Heavy-mineral concentrate contains phosphatized

grains (including radiolarians?), lesser pyritized

radiolarians and sponge spicules, phosphatized

sponge spicules, and lesser sphalerite(?).

Light-mineral residue includes spiculitic carbonate

rock fragments.

6.0 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

128

EMA (Red Dog

plate; Gul

subplate)

[cont.]

De Long Mtns.

A-2

68°10'03"/

162°58'29"

26 small indet. bar and blade fragments

CAI=3.5

[DDH 807, composite conodont sample 4: 1357.5,

1358.8-60, 1360.6-62.0, 1362.6-64, 1367.0-67.5,

1368-69.5, 1370.5-71.5 ft; 33494-PC]

Unit known to be

Mississippian in age.

Indeterminate (too few

conodonts). Distal

winnow.

Sample ~147 ft below top of second of three structural

repeats of Ikalukrok unit; this interval of Ikalukrok

is fault-bounded above and below. Sample from 18-

ft-thick calcareous lithic turbidite.

1357.5-1371.5 ft: Single carbonate turbidite grading

upward from 1) poorly sorted, medium-grained,

noncalcareous sandstone with 10-15% mudstone

flasers, rip-ups, and laminae, to 2) alternations of

massive calcareous sandstone (in layers ≤ 4 ft) and

graded intervals (up to 2.5 ft) of calcareous

sandstone to sandy limestone, to 3) bioturbated

medium-dark- to medium-gray siltstone and very

fine grained sandstone, and, finally, to 4) brownishblack (outer) and dark-gray (inner) mudstone about

8 cm thick.

Thin section data:

1370.7 ft: Lithic turbidite with abundant carbonate

clasts and calcite cement; also crinoid ossicles,

productid spines, phosphatic bioclasts, and clasts of

quartz, brown mud, and chlorite.

1374 ft: Finely interlayered calcareous silty mudstone

with small bioclasts and quartz sandstone with minor

productid spines and crinoid ossicles.

6.0 kg of rock was processed.

(Gul subplate) Barren

[DDH 807, composite conodont sample 5: 1459.6-

68.0 ft]

Sample ~249 ft below top of second of three structural

repeats of Ikalukrok unit; this interval of Ikalukrok

is fault-bounded above and below. Sample from 12-

ft-thick calcareous lithic turbidite.

1459.6-68.0 ft: Poorly sorted, calcareous siltstone to

fine-grained sandstone with remnant sedimentary

layering partly obscured by burrowing.

Thin section data:

1462.8 ft: Lithic turbidite with clasts of quartz,

carbonate, and mudstone in calcite cement; bioclasts

include foraminifers and pyritized spines.

7.28 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

129

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°09'50"/

162°57'35"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 924 (Anarraaq deposit), composite conodont

sample: 2008.5-2009.5, 2013-2014.5, 2015.7-

2017, 2017.5-2019 ft]

Sample ~330 ft below gradational contact of Siksikpuk

Formation and Ikalukrok unit, ~80 ft below base of

thick barite interval at top of Ikalukrok, and ~137 ft

above top of mineralized (sulfide) zone. Sample is

calcareous lithic turbidite >12 ft thick.

2008.5-2019: Medium- to medium-dark-gray (outer),

medium-dark- to dark-gray (inner) sandy limestone;

grades upward from very coarse grained to coarsegrained, with pelmatozoan ossicles and round to

irregular pyrite and mud clasts, to medium- and finegrained.

Thin section data:

2006.5, 2019 ft: Lithic turbidite with noncarbonate

mud matrix; clasts include quartz, carbonate, and

chert.

6.75 kg of rock was processed.

Sample from lithic turbidite zone of middle interval of

Ikalukrok unit of Kelley, Dumoulin, and Jennings

(2004).

130

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°09'50"/

162°57'22"

Barren

[DDH 808 (Anarraaq deposit), composite conodont

sample: 1935-36, 1938-39.5, 1941-41.3, 1943,

1949, 1957, 1961, 1963, 1964.5, 1967, 1969, 1972,

1973.5, and 1976 ft]

Sample ~367.5 ft below faulted contact of Siksikpuk

Formation and Ikalukrok unit, ~14 ft below base of

thick barite interval at top of Ikalukrok, and ~247 ft

above mineralized sulfide zone. Sample from

interval ~50 ft thick of calcareous radiolarite and

lesser noncarbonate mudstone.

1935-1976 ft: Varying proportions of medium- to darkgray (inner), very fine grained limestone with

scattered black mudstone(?) grains, and grayishblack to black, locally siliceous mudstone.

Thin section data:

1938, 1955, 1967, 1976.7 ft: Calcareous radiolarite

with local siliceous laminae and barite veins.

6.0 kg of rock was processed.

Sample from chert and calcareous radiolarite zone of

middle interval of Ikalukrok unit of Kelley,

Dumoulin, and Jennings (2004).
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

131

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°09'46"/

162°57'44"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 813 (Anarraaq deposit), composite conodont

 sample 1: 2002.2-03.2 and 2004.8-06.0 ft]

Sample ~239 ft below conformable contact of

Siksikpuk Formation and Ikalukrok unit, ~36 ft

below base of 203-ft-thick barite interval, and ~236

ft above mineralized sulfide zone. Sample from ~4-

ft interval of calcareous radiolarite and lesser

noncarbonate mudstone and chert. See table 14 for

radiolarian sample from this drill hole.

2002.2-2006 ft: Mottled, medium- to medium-lightgray (outer) and medium-dark-gray (inner) micrite

and carbonaceous micrite with probable radiolarians.

Thin section data:

2002.5 ft: Calcareous radiolarite.

Sample weight not recorded.

Sample from chert and calcareous radiolarite zone of

middle interval of Ikalukrok unit of Kelley,

Dumoulin, and Jennings (2004).

3 indet. bar or blade fragments

CAI cannot be readily determined because

conodonts are covered and (or) coated with

argillaceous and organic matter. CAI=4 or less

[DDH 813, composite conodont sample 2: 2097.1-

2098 ft]

Mississippian (on the basis of

local stratigraphy).

Indeterminate (too few

conodonts).

Sample ~131 ft below base of 203-ft-thick barite

interval and ~145 ft above mineralized sulfide zone.

Sample from ~11 ft zone of carbonate turbidites.

2097.1-2098 ft: Calcareous lithic turbidite with saltand-pepper texture; medium-light- to medium-darkgray (outer), medium-dark- and dark-gray (inner),

massive-bedded to mottled, medium- to finegrained. Contains rounded black chert(?) grains,

radiolarians(?), carbonate mud, and pyrite.

Thin section data:

2098 ft: Poorly preserved calcareous clasts in a

calcareous matrix, with some phosphate clasts and

pyritized radiolarians.

0.92 kg of rock was processed.

Sample from lithic turbidite zone of middle interval of

Ikalukrok unit of Kelley, Dumoulin, and Jennings

(2004).
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

132

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°09'46"/

162°57'22"

2 indet. bar fragments

CAI=3.5

[DDH 810 (Anarraaq deposit), composite conodont

sample 1: 1919-40 ft; 33495-PC]

Mississippian (on the basis of

local stratigraphy).

Indeterminate (too few

conodonts).

Sample ~360 ft below conformable contact of

Siksikpuk Formation and Ikalukrok unit, from basal

part of 367-ft-thick barite interval, ~216 ft above

mineralized sulfide zone. Sample from zone of

laminated barite with interbeds of calcareous

radiolarite and noncarbonate mudstone.

1919-1940 ft: Laminated, medium-dark-gray, finegrained calcitized radiolarite (layers as much as 1-

1.5 cm thick), slightly calcareous mudstone, and

mudstone with local (<5%) calcite spar veins.

Thin section data:

1919, 1920, 1925, 1940 ft: Calcareous radiolarite with

minor mud clasts and barite veins. Local fine

preservation of radiolarian test structure; some

radiolarians still silica, others pyritized.

Heavy-mineral concentrate chiefly composite

carbonaceous phosphatized grains with minor

fluorite(?).

5.68 kg of rock was processed.

Sample from basal part of barite interval of Ikalukrok

unit of Kelley, Dumoulin, and Jennings (2004).

1 indet. bar fragment

CAI=~3

[DDH 810, composite conodont sample 2: 2028-

29.1 ft; 33496-PC]

Mississippian (on the basis of

local stratigraphy).

Indeterminate (too few

conodonts).

Sample ~102 ft below base of thick barite interval at

top of Ikalukrok unit and ~127 ft above mineralized

sulfide zone; from ~1.5-ft-thick lithic turbidite.

2028.6-2029.1 ft: Medium-gray (outer) and dark-gray

(inner) calcareous sandstone bed with rounded black

chert(?) grains.

Thin section data:

2028 ft: Lithic turbidite with quartz, carbonate and

mud clasts, crinoid ossicles, and calcite cement.

1.3 kg of rock was processed.

Sample from lithic turbidite zone of middle interval of

Ikalukrok unit of Kelley, Dumoulin, and Jennings

(2004).
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

133

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°09'41.8"/

162°57'22"

Barren. No conodonts or other mineralized fossil

materials were found

[DDH 806 (Anarraaq deposit), composite conodont

sample: 1878, 1881-82.5, 1916, 1940, 1942, and

1944.5 ft]

Sample ~282 ft below gradational contact of Siksikpuk

Formation and Ikalukrok unit, from basal part of

365-ft-thick barite interval, ~154 ft above

mineralized sulfide zone. Sample from zone of

calcareous and siliceous radiolarite interbedded with

locally calcareous barite and noncarbonate

mudstone.

1878-1944.5 ft: Medium-dark-gray (outer) and darkgray (inner), laminated, fine-grained limestone

(calcareous radiolarite) and dark-gray (outer)

noncarbonate, partly burrowed siliceous mudstone.

Thin section data:

1879, 1942 ft: Calcareous radiolarite.

1818.5 ft: Siliceous radiolarite with layers of

noncarbonate mud and pelloids.

Heavy-mineral concentrate contains abundant

composite phosphatized rock fragments.

6.34 kg of rock was processed.

Sample from basal part of barite interval of Ikalukrok

unit of Kelley, Dumoulin, and Jennings (2004).

134

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°09'40"/

162°55'36.8"

1 Pa element fragment of an ozarkodinid (likely

Bispathodus utahensis Sandberg and Gutschick)

29 indet. bar, blade, and platform fragments

CAI=3.5? or 4? but maybe less; conodonts have

adventitious organic matter, making CAI

determination difficult.

[DDH 925 (Anarraaq deposit), composite conodont

sample: 877.5-878.5, 879.5-880, 882.5-883.5,

884.5-885.5, 886-886.7, and 887-887.5 ft; 33622-

PC]

Mississippian; likely late

Kinderhookian-Osagean.

Indeterminate; small

size of conodont

fragments indicates a

postmortem winnow.

Sample ~180 ft below conformable contact of

Siksikpuk Formation and Ikalukrok unit. Sample is

fining upward calcareous lithic turbidite ~15 ft thick.

877.5-887.5: Medium-light-gray at base and dark gray

at top (outer), medium-dark-gray at base and darkgray to grayish-black at top (inner), with graded

laminae, fine-scale cross laminations, and angular to

subrounded mud and pyrite clasts ≤1 mm long.

Thin section at 886.5 ft is diverse lithic turbidite with

abundant carbonate clasts and calcite cement;

bioclasts include crinoid ossicles, brachiopod(?)

fragments, phosphatic bioclasts, and silicified

productid spines. Other grains include angular quartz

and mud clasts.

5.34 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

135

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°10'6.1"/

162°54'3.2"

All conodonts are completely or partly covered by

adventitious organic matter.

1 juvenile Pa element Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg and

Gutschick

1 unassigned incomplete Sb element

15 indet. bar and blade fragments

CAI=3 or 4

[DDH 780 (east of Anarraaq deposit), 760 ft;

33483-PC]

Early-middle Late

Mississippian

(KinderhookianMeramecian).

Indeterminate; too few

generically identifiable

conodonts.

Samples upper 1 ft of 4-ft-thick carbonate turbidite in

upper part of Ikalukrok unit, ~45-50 feet below an

apparently unfaulted contact with the Siksikpuk

Formation and 70 feet above the mineralized sulfide

zone.

Medium- to dark-gray, finely laminated, very fine

grained limestone. Thin section is calcareous

radiolarite with abundant calcitized radiolarians.

1.0 kg of rock was processed.

Sample collected by D.L. Leach.

139

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°05'0.1"/

162°49'23.4"

All conodonts have minor to extensive adventitious

carbonaceous matter and (or) pyrite making

taxonomic determination and CAI analysis

difficult.

5 P elements Bactrognathus sp. indet.

3 Hindeodella segaformis s.f. element fragments

(=S element bar fragments of Scaliognathus

anchoralis Branson and Mehl)

3 incomplete Pa elements Polygnathus communis

communis Branson and Mehl

1 Pa element fragment Polygnathus sp. indet.

Unassigned elements:

 5 Pb (3 morphotypes), 5 M (2 morphotypes), 2 Sa,

1 Sb, and 6 Sc (3 morphotypes)

224 indet. bar, blade, and platform fragments

CAI=2.5 or 3

[DDH 664 (Paalaaq deposit), 1018.3-1020.5 ft;

33621-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralis-Do.

latus Zone)

Postmortem transport

within or from a slope

or basin environment;

all conodonts are

incomplete and most

are relatively small

fragments suggesting,

at least in part, a

winnow.

Sample near top of ~65-ft-thick deformed, faultbounded interval of Ikalukrok unit.

1018.3-1020.5: Medium-gray (outer), medium-darkgray (inner) calcareous radiolarite.

Thin section data:

1018.5, 1020.5: calcareous radiolarite; relict

radiolarians preserved in concretions of radial

carbonate.

3.3 kg of rock was processed.

144

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'37.6"/

162°49'8.7"

Barren

[DDH 500 (Aqqaluk deposit, 360 ft]

Sample from ~20-ft-thick calcareous interval in a faultbounded section of the Ikalukrok unit.

Very sooty, black, very fine grained limestone. Thin

section is calcareous radiolarite with >30-40%

radiolarians; some test structures well-preserved, but

most replaced by monocrystalline calcite.

0.4 kg of rock was processed.
Table 1. Conodont samples from the Ikalukrok unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

EK, I. Ellersieck; and KE, K. Evans. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless

otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

149

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'26.5"/

162°50'06.7"

Unassigned elements:

 1 M and 2 Sb

7 indet. bar fragments

CAI=4 or less (CAI difficult to determine as all

conodonts are coated with organic matter).

[DDH 205 (Main deposit), 239 ft; 33485-PC]

Mississippian, as stratigraphic

identification is firm.

Indeterminate (too few

conodonts).

Sample 10 ft below top of 14-ft interval of Ikalukrok

unit in fault contact below Kivalina unit.

One-ft-thick black limestone turbidite, interbedded

with black sooty mudstone. Thin section is

calcareous radiolarite; radiolarians 80-90% of thin

section.

0.7 kg of rock was processed.

154

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'20.2"/

162°49'01.5"

Barren

[DDH 8 (Main Deposit), 95-100.5 ft]

Chert and cherty shale with disseminated pyrite and

sphalerite, near top of zone of sulfide mineralization

in the Ikalukrok unit. See table 2 for Kivalina unit

sample from this drill hole.

3 kg of rock was processed in hydrofluoric acid.

Sample collected by D. Moore, I.L. Tailleur, and L.E.

Young.

156

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'11"/

162°49'51"

1 Pa? element blade

1 indet. bar fragment

CAI=~3.5

[DDH 186 (Main Deposit), 94 ft; 33484-PC)

Mississippian, as stratigraphic

identification is firm.

Indeterminate (too few

conodonts).

Sample 94 ft below top of 125-ft-thick section of

Ikalukrok unit in fault contact above Kivalina unit.

Samples 1-ft-thick black limestone turbidite in 6-ft

interval of 2- to 15-inch turbidites. Thin section is

calcareous radiolarite with very abundant

radiolarians and a slightly dolomitic matrix.

0.62 kg of rock was processed.

157

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°03'24.3"/

162°49'40.6"

Barren

[DDH 13 (Qanaiyaq Deposit), 223-230 ft]

Very pyritic bleached chert and shale from top of

mineralized interval in the Ikalukrok unit.

1.1 kg of rock was processed.

Sample collected by D. Moore, I.L. Tailleur, and L.E.

Young.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

1

EMA (Red Dog

plate)

De Long Mtns.

B-4

68°15'16.8"/

164°02'33"

Barren

[99AD23K]

Sample near top of Kivalina unit, just below chert-rich

Ikalukrok unit.

Brown-gray, light-brown-gray-weathering, very fetid,

fine-grained limy dolostone in irregular 5 to 7 cmthick beds; local burrows, parallel laminae, and chert

bands. Some interbeds and layers of calcareous and

siliceous spiculite. Thin section is organic-rich, finecrystalline dolostone.

Heavy-mineral concentrate includes minor phosphatic

brachiopod fragments.

Weight of rock processed not recorded; likely 8-9 kg.

17

EMA (Red Dog

plate)

De Long Mtns.

A-3

68°07'48"/

163°33'00"

10 Pa element fragments Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg and

Gutschick

Unassigned elements:

 1 M and 1 Sa

26 indet. bar, blade, and platform fragments

CAI=3-4

[79CX227 + 0 m]

latest Late Devonian-middle

Late Mississippian (late

Famennian-late

Meramecian).

Postmortem transport

within or from a slope

or basin depositional

setting

Submitted as Kivalina Limestone; mapped by Mayfield

and others (1990) as Kayak Shale (Mk1). Sample at

base of 47-m-thick section of carbonate and shale.

The conodonts are typical of the Kuna Formation but

are surface swimmers and occur in all environments.

Bi. stabilis and Bi. utahensis are most abundant in

deeper water deposits. Thus, their presence here

without other species strongly suggests a Kuna

depositional setting and not the Kayak Formation.

3.3 kg of rock was processed.

Fossil loc. 33, Mayfield and others (1990).

3 indet. bar, blade, or platform fragments

CAI=3-4

[79CX227 + 20 m]

Because sample is in the same

section and 20 m above

79CX227 + 0 m, it is most

likely the same age.

Indeterminate (too few

conodonts).

Sample near mid-point of 47-m-thick section of

carbonate and shale.

2.72 kg of rock was processed.

30

EMA (Red Dog

plate)

De Long Mtns.

A-3

68°04'01.8"/

163°12'30"

1 incomplete unassigned digyrate element

2 indet. bar and blade fragments

CAI=~4

[00AD101A; 33640-PC]

Mississippian Indeterminate (too few

conodonts).

From type area of Kivalina unit of Kuna Formation.

Two-cm-thick nodular layers of orange-weathering,

medium- to dark-gray limestone containing sparse to

abundant crinoid ossicles and rare brachiopods.

Limestone beds separated by dark shale partings.

Thin section is skeletal wackestone with partly

dolomitized matrix; bioclasts include bryozoan,

pelmatozoan, and brachiopod fragments.

Heavy-mineral concentrate includes pyrite-bearing

silicified ostracodes (as single and complete valves)

and very scarce pyrite-bearing bryozoan fragments.

12.2 kg of rock was processed.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

71

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°08'18"/

162°48'36"

3 Pa element fragments Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg and

Gutschick

1 unassigned M element

26 indet. bar, blade, and platform fragments

CAI=3.5-4

[8-16-83A; 29228-PC]

late Late Devonian- early

Late Mississippian (late

Famennian-Meramecian).

Indeterminate (too few

conodonts); normalmarine depositional

setting.

Kivalina unit, within 100 ft of base of unit.

Chiefly black shale and scattered 2 to 10 cm beds of

very fine grained, silty, dark-gray limestone that

weathers light brown to grayish orange.

8.2 kg of rock was processed.

Sample collected by A.G. Harris.

78

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°02'58"/

163°05'31"

1 incomplete juvenile Pa element Gnathodus sp.

indet.

1 juvenile Pa element Gnathodus texanus Roundy

1 Sb-Sc Kladognathus sp. indet. element

1 M or S element fragment Synclydognathus sp.

indet.

2 juvenile P elements Vogelgnathus? sp. indet.

19 indet. bar, blade, and platform fragments

CAI=3.5

[00AD7A; 33628-PC]

late Early-middle Late

Mississippian (late

Osagean-early Chesterian).

Indeterminate (too few

generically determinate

conodonts). Conodonts

indicate postmortem

winnow from a shelf

depositional setting.

Sample from section of Kivalina unit that is

transitional, lithologically and faunally, to the

Utukok Formation.

Medium-light-gray- to orangish-light-gray-weathering,

dark- to medium-dark-gray wackestone/packstone

with pelmatozoan ossicles and columnals as much as

3 cm in diameter and large coral fragments as much

as 40 cm in size; bedding irregular, 5 to 25 cm thick,

with some minor bioturbation.

Thin section is bioturbated crinoidal packstone with

bryozoan and algal fragments; matrix partly

dolomitized.

Heavy-mineral concentrate contains fluorite and rare

ichthyoliths.

10.46 kg of rock was processed.

Loc. 18 (fig. 2) of Dumoulin and others (2004).

Loc. 42 (Ellersieck and others, 1990) near here

contains foraminifers of late Early-Late

Mississippian (Zone 11 or younger) age.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

122

EMA (Red Dog

plate)

De Long Mtns.

A-3

68°10'00"/

163°12'22"

Bispathodus stabilis (Branson and Mehl) or Bi.

utahensis Sandberg and Gutschick

 10 Pa (juveniles and large adults), 1 M, and 1 Sa

elements

1 Idioprioniodus sp. indet. element fragment

48 indet. bar and blade fragments

CAI=3

[DDH Su 41 (Su deposit), composite conodont

sample: 1007.0-08.5, 1018.0-21.5, 1022.7-23.5,

and 1024.0-24.4 ft; 33486-PC]

Early-early Late

Mississippian (middle

KinderhookianMeramecian).

Indeterminate (too few

conodonts);

postmortem transport

within or from the

bispathodid biofacies.

Conodonts suggest a

deep-water, off shelf or

off platform

depositional setting.

Uppermost Kivalina unit, immediately below

gradational contact with overlying Ikalukrok unit.

1007.0-1024.4 ft: Various proportions of laminated to

thin beds (up to 3 cm thick) of medium-light-gray

and medium- to dark-gray (outer) and medium-gray

to grayish-black (inner), chiefly very fine grained

limestone, calcareous mudstone, and noncalcareous

mudstone with <2 to 5% calcite spar veins. Lower

10 cm of sampled interval grades upward from

coarse to very fine carbonate sand, silt(?), and,

finally, to micrite. Coarser intervals are skeletal

packstone-grainstone with dark-gray flattened mud

clasts several millimeters long; bioclasts mainly

pelmatozoan debris.

Thin section data:

1008 ft: Fine-grained calcareous spiculite.

1008.6, 1016.3, and 1020.8 ft: Finely interlayered

calcareous spiculite and skeletal packstone.

1030 ft: Packed crinoidal packstone, partly silicified

and dolomitized, with crinoid ossicles to 2 mm.

Heavy-mineral concentrate contains phosphatic

brachiopod fragments and phosphatized brachiopod

spines.

7.68 kg of rock was processed.

123

EMA (Red Dog

plate)

De Long Mtns.

A-3

68°09'45.4"/

163°12'30.7"

Barren

[DDH Su 31 (Su deposit), 1806-1824 ft]

Uppermost Kivalina unit from just below mineralized

zone at base of Ikalukrok unit at Su deposit. Sample

from 22-ft-thick interval of thinly interbedded black

limestone and dark gray to black shale. See table 1

for Ikalukrok sample from this drill hole.

7.8 kg of rock was processed.

Sample collected by D. Moore, I.L. Tailleur, and L.E.

Young.

124

EMA (Red Dog

plate)

De Long Mtns.

A-3

68°09'42.6"/

163°11'49.2"

Barren

[DDH Su 16 (Su deposit), 1195-1216 ft]

Uppermost Kivalina unit, ~48 ft below mineralized

zone at base of Ikalukrok unit at Su deposit. Sample

from 20-ft-thick interval of medium gray to black,

mostly limy shale, with pyrite and calcite veins. See

table 1 for Ikalukrok sample from this drill hole.

7.46 kg of rock was processed.

Sample collected by D. Moore, I.L. Tailleur, and L.E.

Young.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

137

EMA (Red Dog

plate)

DeLong Mtns.

A-2

68°05'22.8"/

162°50'29.4"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 777 (north of Paalaaq deposit), composite

conodont sample 1: 478-80.4 and 487.6-488 ft]

Sample from upper part of ~2500 ft thick interval of

Kivalina unit that is probably structurally thickened.

478.0-488.0 ft: Light-brownish-gray and mediumlight-gray (outer), dark-gray (inner), fine-grained,

locally graded (in intervals 0.5-4 cm thick)

limestone and noncalcareous to weakly calcareous

mudstone and shale containing ~5% calcite spar

veins.

Thin section data:

483.3 ft: Graded carbonate layers (to 1 cm thick), with

bioclasts (crinoids, spicules), peloids, and mud clasts

(to 1.5 mm); thin interlayers of noncarbonate mud.

486.9 ft: Fine-grained peloidal carbonate with minor

euhedral dolomite and quartz silt.

489 ft: Dolomitic, calcareous spiculite with mud

intraclasts to 1.5 mm long.

4.1 kg of rock was processed.

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 777, composite conodont sample 2: 1088-

89.5, 1090-91, 1096-97, 1101-01.8, 1104, 1106-

07, 1110.5-11.0 and 1117 ft]

Sample from middle part of ~2500 ft thick interval of

Kivalina unit that is probably structurally thickened.

1088.0-1117.0 ft: Interval is at least 50% carbonate.

Various proportions of medium-light- to mediumgray (outer) and medium-dark-gray (inner) shaly

limestone to limestone and medium-dark- to darkgray (outer) and dark-gray to grayish-black (inner)

shale and calcareous shale. Coarsest layers are

medium- to coarse-grained supportstone with

pelmatozoan debris. Some layers bioturbated.

Thin section data:

1088.5 ft: Interlayered noncarbonate mud, calcareous

spiculite, and crinoid grainstone with mud clasts and

quartz silt.

1096.5 ft: Calcareous spiculite.

1110 ft: Fine-grained bioturbated dolostone with minor

quartz silt.

1111.3 ft: Cherty dolostone.

Heavy-mineral concentrate includes rare chalcopyrite.

6.0 kg of rock was processed.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

137

EMA (Red Dog

plate)

[cont.]

De Long Mtns.

A-2

68°05'22.8"/

162°50'29.4"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 777, composite conodont sample 3: 1370.5-

71.5, 1372.5-75, 1378-78.4, 1382-82.2, 1385.5-

86.5, 1387.4-87.5, and 1391-92 ft]

Sample from middle part of ~2500 ft thick interval of

Kivalina unit that is probably structurally thickened.

1370.5-1392.0 ft: Various proportions of mediumdark- to dark-gray (outer), grayish-black (inner)

shale to slightly calcareous shale and very light- to

medium-gray (outer), medium-dark-gray (inner)

limestone (carbonate turbidite beds as much as 4.5 ft

thick, graded and partly bioturbated). Thin section at

1387.4 ft is fine-grained, euhedral to subhedral

dolomite(?) mosaic with sparse bioclasts (crinoids,

spicules).

8.68 kg of rock was processed.

1 Pa element fragment Bispathodus utahensis

Sandberg and Gutschick

1 Pa element Polygnathus communis communis

Branson and Mehl

1 S element bar fragment Scaliognathus anchoralis

Branson and Mehl (="Hindeodella" segaformis

Bischoff s.f.)

1 Pb element of late Early Devonian-Early

Mississippian morphotype

2 Sc (2 morphotypes) elements of late Late

Devonian and Mississippian morphotype

60 indet. bar, blade, and platform fragments

CAI=3

[DDH 777, composite conodont sample 4: 1961.2-

62.0, 1972.7-73.0, 1974, 1979, 1980, 1982, 1989

ft; 33490-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralisDo. latus Zone).

Indeterminate (no

generically determinate

conodonts); forms

present indicate postmortem hydraulic

transport.

Sample from lower part of ~2500 ft thick interval of

Kivalina unit that is probably structurally thickened.

1961.2-1989.0 ft: Various proportions of mediumdark-gray (outer), grayish-black (inner) shale to

calcareous shale, medium-dark-gray (inner)

laminated shaly limestone, and fine-grained

limestone with rare 1 to 2 mm coarser grained

laminae. A coarse-grained intraclast conglomerate

containing dark shale clasts up to 7 mm long is at

1980 ft. Thin section at 1979.9 ft is fine-grained

dolomite with 3-cm-thick layer of coarse skeletallithic clast supportstone. Bioclasts include crinoid

and bryozoan fragments. Other clasts (to 4 mm) are

shale, micrite, and peloidal packstone.

Heavy-mineral concentrate includes scarce phosphatic

brachiopod fragments.

7.25 kg of rock was processed.

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 777, composite conodont sample 5: 2430.3-

39.0 ft]

Sample from lower part of ~2500 ft thick interval of

Kivalina unit that is probably structurally thickened.

2430.3-2439.0 ft: Medium-dark- to dark-gray (outer),

dark-gray to grayish black (inner) shaly limestone

and medium-light- to light-gray (outer) limestone.

Coarser grained carbonate intervals up to 15 cm

thick are fine to medium grained with crinoid debris.

Thin section data:

2437 ft: Most of slide is fine laminae of noncarbonate

and carbonate mud with minor dolomite euhedra and

quartz silt; one layer of bioclasts (crinoid ossicles)

and clasts (micrite with calcareous spicules and

peloids) to 1 mm. Slide looks deformed.

6.02 kg of rock was processed.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

138

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°05'00.5"/

162°49'44.4"

2 S element fragments Scaliognathus anchoralis

Branson and Mehl (="Hindeodella" segaformis

Bischoff s.f.)

5 indet. bar, blade, and platform fragments

CAI=3

[DDH 676 (Paalaaq deposit), composite conodont

sample 1: 671.5-672.4 ft; 33489-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralisDo. latus Zone).

Indeterminate (too few

generically identifiable

conodonts). Conodonts

present indicate a postmortem winnow.

Sample from lower part of ~725 ft thick, highly

deformed interval of Kivalina unit, ~213 ft below

altered keratophyre.

671.5-672.4 ft: Graded turbidite bed made of light- to

medium-light-gray (outer), medium- to mediumdark-gray (inner) carbonate sand, silt, and mud.

Thin section data:

671.5 ft: Fine-grained dolostone.

672.4 ft: Bioclastic supportstone with bryozoan and

pelmatozoan fragments and brown to black mud

clasts.

Heavy-mineral concentrate contains scarce phosphatic

brachiopod fragments.

1.53 kg of rock was processed.

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 676, composite conodont sample 2: 689.5-

696.1 ft]

689.5-696.1 ft: Chiefly a reverse-graded massive bed

(possibly partly homogenized by burrowing) of

light- to medium-gray (outer), medium-dark-gray

(inner), coarse- to fine-grained carbonate with local

dark-gray to black mud clasts.

Thin section data:

689.6 ft: Diverse bioclasts and clasts of brown mud

and chert? (to 1 cm) in fine-grained carbonate

matrix.

690.2 ft: Like 689.6 but finer grained, deformed.

692.9, 694.1 ft: Fine-grained carbonate.

4.92 kg of rock was processed.

140

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'55"/

162°49'55"

1 indet. bar or blade fragment

CAI=~1.5

[DDH 580 (Paalaaq deposit), 576-77 ft]

Middle Ordovician-Triassic. Indeterminate (too few

conodonts).

Fault-bounded section of Kivalina unit, 537 ft thick;

sample of thin limy layer 20 ft above base.

Light-gray, very fine grained limestone. Thin section is

deformed calcisiltite, cut by numerous irregular

stylolites and sparry calcite veins; 2-5% quartz silt.

1.2 kg of rock was processed.

Barren

[DDH 580, 592-93 ft]

Sample 5 ft above base of 537-ft Kivalina unit section

and 11 ft below top of 16-ft-thick limestone layer.

Light-gray, very fine grained limestone with possible

peloids. Thin section is very finely crystalline

carbonate (mostly dolomite?) with vague pelloidal

texture, minor quartz silt, and trace phosphatic

bioclasts.

Heavy-mineral concentrate includes fluorite(?).

1.0 kg of rock was processed.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

141

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'54.6"/

162°49'32.4"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 710 (Paalaaq deposit), composite conodont

sample: 346-357.6 ft]

Sample from middle part of ~670 ft thick highly

deformed interval of Kivalina unit, ~77 ft above

altered ash layer.

346-357.6 ft: Interbedded dark-gray to grayish-black

(outer), dark-gray to black (inner) mudstone and

light- to medium-light-gray (outer) carbonate

(mostly micrite, lesser silt- and fine-sand size).

Interbedded chiefly on mm to cm scale, but

carbonate layers up to 3 cm thick. Interval includes

~10% calcite spar veins and 1 to 3% fine calcite

veins. Black mud(?) rip-up clasts to 3 cm long.

Thin section data:

346.9 ft: Thin laminae of micrite, noncarbonate mud,

and carbonate sand (micrite clasts to 2 mm) with

calcareous spicules, and rare radiolarians.

348.6 ft: Calcareous, dolomitic(?) radiolarite, some

radiolarians are pyritized.

Heavy-mineral concentrate includes rare pyritized

radiolarian steinkerns.

5.86 kg of rock was processed.

142

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'54.3"/

162°49'24.3"

Scaliognathus anchoralis Branson and Mehl

 2 Sa elements and 3 bar fragments

(="Hindeodella" segaformis Bischoff s.f.) [pl. 1,

figs. 9, 10]

Unassigned elements:

 2 Pb (2 morphotypes) and 2 M

6 indet. bar and blade fragments

CAI=3.5

[DDH 640 (Paalaaq deposit), composite conodont

sample: 429-453 ft; 33488-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralisDo. latus Zone).

Indeterminate (too few

generically identifiable

conodonts). Conodonts

present indicate

postmortem transport

to a slope or deeper

water depositional

setting.

Sample from 34-ft-thick section of Kivalina unit

bounded above and below by mélange, within ~750

ft thick interval of deformed Kivalina.

429-453 ft: Light- to medium-gray (outer), mediumdark-gray (inner), amalgamated, graded, fine- to

medium-grained carbonate turbidite beds 6 to 8 cm

thick, interbedded with noncalcareous grayish-black

(outer), grayish black to black (inner) mudstone.

Limestone is in discrete beds and forms 30-35% of

interval. Bedding near vertical in lower half of

sampled interval. Thin section at 640.5 ft is sparse

calcareous radiolarite with brown muddy clasts and

local patches of fine-grained silica.

6.0 kg of rock was processed.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

143

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'50"/

162°49'24.4"

4 Pa element fragments Bispathodus utahensis

Sandberg and Gutschick

1 Kladognathus sp. indet. bar fragment

11 indet. bar, blade, and platform fragments

CAI=~2.5 or 3

[DDH 636 (Paalaaq deposit), 534 ft; 33422-PC]

Early-early Late

Mississippian (late

KinderhookianMeramecian)

Indeterminate (too few

conodonts); conodonts

present indicate outer

shelf or deeper water

depositional setting.

Fault-bounded section of Kivalina unit, 44 ft thick;

sample 10 ft below top.

Sample is 6-cm-thick layer of light-gray-weathering,

fine- to medium-grained limestone (skeletal

packstone to grainstone with abundant crinoids).

Thin section is packed skeletal grainstone; bioclasts

mostly crinoid ossicles (to 1.5 mm) and lesser

foraminifers, bryozoan fragments, and rare ostracode

valves. Pyrite replaces some skeletal grains.

Heavy-mineral concentrate includes minor pyritized

bioclasts (mainly bryozoans).

0.2 kg of rock was processed.

Barren

[DDH 636, 536-37 ft]

Sample 13 ft below top of 44-ft-thick, fault-bounded

section of Kivalina unit.

Interval of light-gray, very fine grained, silty(?)

limestone layers (0.5-8 cm thick) interbedded with

dark-gray limy shale. Three thin sections taken from

limestone layers in this interval. Two are white

sparry calcite with cone-in-cone structure; the third

is graded calcisiltite to calcisandstone with flattened

noncalcareous mud intraclasts and rare identifiable

bioclasts (pelmatozoan and bryozoan fragments,

calcareous spicules and calcitized radiolarians?).

Trace quartz silt.

0.5 kg of rock was processed.

145

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'34"/

162°49'28.5"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 495 (Aqqaluk deposit), composite conodont

sample 1: 488-488.3 and 493-495.7 ft]

Sample of Kivalina unit ~5 ft below mélange zone at

contact with overlying Ikalukrok unit.

488.0-495.7 ft: Laminated to very thin bedded (0.1-1

cm) light-gray to medium-dark-gray (outer),

medium-dark-gray and grayish-black (inner)

limestone and subordinate (<5 to 10%) mudstone

with <5% calcite spar veins. Coarsest layers are

medium-grained skeletal supportstone with

pelmatozoan debris. Rare mud rip-up clasts to 4 cm

long. Thin section at 493.5 ft has bioclasts and

peloids in deformed, laminated matrix of

noncarbonate and carbonate mud.

4.94 kg of rock was processed.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

145

EMA (Red Dog

plate)

[cont.]

De Long Mtns.

A-2

68°04'34"/

162°49'28.5"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 495, composite conodont sample 2: 510.4-

511.0, 511.5-513, and 514-516 ft]

Sample of Kivalina unit ~27 ft below mélange zone at

contact with overlying Ikalukrok unit.

510.4-516.1 ft: Laminated to irregularly laminated very

thin beds (1-3 mm) of light- to medium-dark-gray

(outer) and medium-dark- to dark-gray (inner)

limestone with <5% mudstone. Coarsest layers (to 2

cm thick) are medium-grained with dark mud(?)

clasts. Thin section at 516.4 ft is calcareous spiculite

with micrite clasts and quartz silt and sand.

Heavy-mineral concentrate contains rare sphalerite(?).

5.76 kg of rock was processed.

146

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'33.7"/

162°49'20.7"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 499 (Aqqaluk deposit), composite conodont

sample: 447.8-457 ft]

Sample of Kivalina unit 3 ft below gradational contact

with mineralized zone at base of Ikalukrok unit.

447.8-457.0 ft: Various proportions of laminated to

very thin bedded (0.1-0.5 cm), medium-light- to

light-gray (outer), medium-dark-gray (inner)

limestone, calcareous mudstone, and medium- to

dark-gray (outer) and medium-dark-gray (inner)

mudstone with 1-2% calcite spar veins. Coarsest

layers are fine to very fine grained, with

pelmatozoan(?) fragments.

Thin section data:

447 ft: Fine-grained argillaceous rock with deformed

(flattened) fabric.

454.2 ft: Thin layer of fine-grained carbonate with

pyritized bioclasts.

6.0 kg of rock was processed.
Table 2. Conodont samples from the Kivalina unit of the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. DDH,

diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris unless otherwise indicated. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

153

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'20.2"/

162°49'31.4"

Barren. No conodonts or other mineralized fossil

materials were found.

[DDH 415 (Main deposit); composite conodont

sample: 110-148.5 ft]

Sample from lower part of 80-ft-thick fault-bounded

section of Kivalina unit that overlies another faulted

section of Kivalina(?) that contains altered ash beds.

110-148.5 ft: Various proportions of laminated to very

thin bedded (up to 5 cm), light- to medium-lightgray (outer) and medium-dark-gray (inner)

limestone and calcareous mudstone, and black

(outer) and dark-gray (inner) noncalcareous

mudstone, with 10-30% calcite spar veins; rare cross

laminations and graded beds. Coarsest layers are

medium- to coarse-grained skeletal packstone and

grainstone.

Thin section data:

115, 116.5, and 124.5 ft: Bioclasts (mainly crinoid

ossicles, lesser spicules and calcispheres) and local

mud clasts in finely laminated matrix of carbonate

and noncarbonate mud; all samples look deformed.

6.24 kg of rock was processed.

154

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'20.2"/

162°49'01.5"

Barren

[DDH 8 (Main deposit), 285-293.5 ft]

Limestone and shale of the Kivalina unit, ~8 ft below

mineralized horizon at base of Ikalukrok unit. See

table 1 for Ikalukrok sample from this drill hole.

3.9 kg of rock was processed.

Sample collected by D. Moore, I.L. Tailleur, and L.E.

Young.

155

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'14.7"/

162°49'37.7"

Barren

[DDH 77 (Main deposit), 364-391 ft]

Silicified shale and limestone of the Kivalina unit, just

below sulfide mineralization at base of Ikalukrok

unit; contains sphalerite and pyrite veins.

8.4 kg of rock was processed.

Sample collected by D. Moore, I.L. Tailleur, and L.E.

Young.
Table 3. Conodont samples from the Kuna Formation

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; AK, J.S. Kelley; and MD, C.F.

Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by

J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

24

EMA (Key

Creek plate)

De Long Mtns.

A-3

68°07'08"/

163°17'14"

All conodonts are partly or completely coated with

organic matter.

Bispathodus utahensis Sandberg and Gutschick

 26 Pa, 3 Pb, 3 M, 3 Sa, and 2 Sb elements

Idioprioniodus conjunctus (Gunnell)

 4 Pa, 1 M, and 1 Sc element fragments

Kladognathus tenuis (Branson and Mehl)

 3 Pa-Pb, 2 M, and 6 Sb-Sc elements

1 Sc element Scaliognathus anchoralis Branson

and Mehl

Unassigned elements:

 2 Pb (2 morphotypes) and 2 Sc

199 indet. bar, blade, and platform fragments

CAI=~3

[00AD24A; 33635-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralis-Do.

latus Zone).

Bispathodid-digyrate

biofacies: conodonts

indicate a basinal

depositional setting.

113.5 ft below top of Kuna Formation at IP Creek.

Very pale orange- to grayish-orange-weathering,

pinkish to medium-dark-gray, finely sucrosic, blocky

weathering dolostone. Thin section is organic-rich

fine-crystalline dolostone.

13.1 kg of rock was processed.

Loc. 12 (fig. 2) of Dumoulin and others (2004).

103

EMA (Key

Creek plate)

De Long Mtns.

B-1

68°21'21"/

162°02'16"

1 juvenile Pa element Eotaphrus sp. indet.

3 Pa elements Polygnathus communis Branson and

Mehl [pl. 1, fig. 14]

Scaliognathus anchoralis Branson and Mehl:

 3 Sc and 31 bar fragments [pl. 1, fig. 15]

Unassigned elements:

 10 juvenile Pa, 4 Pb (4 morphotypes), 2 M (2

morphotypes), 1 Sa, and 3 Sb (3 morphotypes)

52 indet. bar, blade, and platform fragments

CAI=2

[00AD17H; 33631-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralis-Do.

latus Zone).

Postmortem transport

within or from a slope

depositional setting

with minor shallow

water components

(Eotaphrus sp.).

Sample from middle(?) part of Kuna Formation at

August Creek; see table 11 for Kayak Shale sample

from this locality.

Medium-light-gray- and medium-gray-weathering,

medium-gray to medium-dark-gray, fine to very fine

grained limestone in beds 3 to 8 cm thick with 10-

20% chert. Thin-section is a calcareous spiculite.

10.2 kg of rock was processed.

Loc. 2 (app. 1) of Dumoulin and others (2004).
Table 3. Conodont samples from the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; AK, J.S. Kelley; and MD, C.F.

Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by

J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

103

[cont.]

De Long Mtns.

B-1

68°21'21"/

162°02'16"

4 Pa element fragments Bispathodus utahensis

Sandberg and Gutschick

1 juvenile Pa element Dollymae hassi Voges?

2 Pa elements Doliognathus latus Branson and

Mehl

6 P elements Eotaphrus burlingtonensis Pierce and

Langenheim [pl. 1, figs. 11-13]

2 Pa elements Gnathodus cuneiformis Mehl and

Thomas [pl. 1, figs. 18, 19]

32 Sb & Sc element fragments Scaliognathus

anchoralis and (or) Doliognathus latus

15 Pa elements Polygnathus communis communis

Branson and Mehl

Unassigned elements:

13 Pb (2 morphotypes, most are probably in the

apparatus of D. latus) and 17 M (3 morphotypes)

~100 indet. bar, blade, and platform fragments

CAI=3

[79MD44C; 27506-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralis-D.

latus Zone).

This sample correlates with

92AD35 (31781-PC) from

near the base of the type

section of the Kuna

Formation in the Howard

Pass B-3 quadrangle.

Sample 92AD35, however,

is biostratigraphically more

diagnostic and indicates the

lower part of the Sc.

anchoralis-Do. latus Zone.

Mixed biofacies.

Diverse assemblage of

both shallow-water (E.

burlingtonensis) and

deep-water (D. hassi)

forms. Overall species

association indicates

outer shelf or slope

depositional setting.

Sample from lower 1-m-thick carbonate zone in Kuna

Formation; stratigraphic position relative to

00AD17H is uncertain.

4.7 kg of rock was processed.

Fossil loc. 11, Curtis and others (1990).

106

EMA (Key

Creek plate)

De Long Mtns.

B-1

68°16'04"/

162°09'27.5"

1 digyrate Pb element

5 indet. bar and blade fragments

CAI=3

[97AK59C]

post-Devonian Paleozoic Indeterminate (too few

generically identifiable

conodonts).

Sample taken near base of Kuna Formation, directly

above contact with Kayak Shale, from limestone

interval a few ft thick.

Flaggy, sooty dark-gray limestone in beds 3 to 5 cm

thick (turbidites?). Thin section is calcareous spiculite

(a few spicules are siliceous) with rare calcitized

radiolarians(?). Matrix is noncalcareous and

calcareous mud with dolomite rhombs and trace

monocrystalline quartz.

Heavy-mineral concentrate is chiefly pyritized spine

fillings and (or) spicules.

13.6 kg of rock was processed.

Shale ~20 ft above limestone interval yielded common

small circular spores and scolecodonts and rare

?densospore rim fragments of possible Carboniferous

age (H. Haga, unpublished fossil report, 1997).
Table 3. Conodont samples from the Kuna Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; AK, J.S. Kelley; and MD, C.F.

Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by

J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

107

EMA (Key

Creek plate)

De Long Mtns.

B-1

68°15'31.4"/

162°13'20"

1 Pa element fragment Gnathodus texanus

Roundy?

12 indet. bar and blade fragments

CAI=3.5

[97AK74A]

latest Early-middle Late

Mississippian (late Osageanearly Chesterian).

Indeterminate (too few

conodonts). Probably

open-marine

depositional setting.

Part of 158-ft measured section of upper Kuna

Formation and lower Etivluk Group, sampled chiefly

for radiolarians; see table 14 for additional samples

from this locality. Sample ~5 ft above base of section

and ~83 ft below contact with Etivluk.

Brown-gray carbonate (beds ~5 cm thick) interbedded

with chert. Thin section is fine-grained dolomite

(crystals 20-100 μm), micrite, and sparry calcite, with

<1% monocrystalline quartz, trace crinoid ossicles,

and irregular spar-filled fenestrae(?).

Heavy-mineral concentrate is chiefly barite, minor

dolomitized and baritized composite grains, and very

minor pink fluorite(?).

6.5 kg of rock was processed.

Loc. 6 (app. 1) of Dumoulin and others (2004).

Gnathodus texanus Roundy (adults and juveniles,

many complete):

 23 Pa, 3 Pb, 4 M, and 3 Sc elements [pl. 1, fig. 17]

1 M element Idioprioniodus sp. indet.

6 Pa elements (mostly fragments)

Rhachistognathus prolixus Baesemann and Lane

[pl. 1, fig. 16]

Unassigned elements:

 1 M and 1 Sc element

213 indet. bar, blade, and platform fragments

(overwhelmingly free blade fragments of, most

likely, G. texanus)

CAI=3.5

[97AK74F; 33404-PC]

middle Late Mississippian

(early Chesterian).

G. texanus biofacies:

open-marine shelf or

deeper water

depositional

environment. Presence

of Rhachistognathus

suggests seaward

transport of highenergy, shoal-water

forms.

Sample ~40 ft above 97AK74A and ~44 ft below

contact with Etivluk Group.

Chert in nodular beds, 2- to 10-cm-thick, with shale

partings, overlain by medium-dark-gray, laminated,

fine-grained limestone. Thin section is chert with

abundant radiolarians and sponge spicules (siliceous,

calcareous, and pyritized). Radiolarians few to 50%

and graded(?); some have well-preserved test

structure.

Heavy-mineral concentrate is chiefly baritized

composite grains (including chert) and conodonts.

7.1 kg of rock was processed.

158

EMA (Key

Creek plate,

near transition

to Red Dog

plate)

De Long Mtns.

A-2

68°05'8.2"/

162°45'37.1"

Nearly all the conodonts are partly or extensively

coated with gritty organic matter.

2 incomplete Pa elements Pseudopolygnathus sp.

Unassigned elements:

 1 M and 1 S

18 indet. bar, blade, and platform elements

CAI=~2.5-3.5

[DDH 587 (east of Paalaaq deposit), 134 ft; 33421-

PC]

Early Mississippian Indeterminate (too few

conodonts).

3-ft-thick turbidite bed in Kuna Formation; sample

>100 ft above gradational contact with Kayak Shale.

See table 11 for Kayak sample from this locality.

Dark-gray, carbonaceous, shaly limestone with

calcitized radiolarians(?). Thin section is peloids,

lime mud intraclasts, calcareous spicules, and

calcitized radiolarians in a finely crystalline matrix of

calcite (and lesser dolomite?).

0.4 kg of rock was processed.

Sample collected by J.A. Dumoulin.
Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic Creek allochthon

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector unless otherwise indicated: AD, J.A. Dumoulin; EK, I.

Ellersieck; JS, J.M. Schmidt; and KE, K. Evans. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

7

PCA (Amaruk

plate)

De Long Mtns.

B-3

68°18'11.8"/

163°14'9.5"

Barren

[KE98-16B]

Sample 100 ft below highest exposed Lisburne Group.

Light-gray-weathering, very light gray, laminated

dolostone, partly siliceous and locally interbedded

with chert; some grainy (bioclastic?) layers. Thin

section is euhedral dolomite mosaic with minor

intercrystal silica; some vugs contain dead oil(?).

Heavy-mineral concentrate includes rare siliceous

single and double-axon sponge spicules.

5.42 kg of rock was processed.

Loc. 2 (fig. 2) of Dumoulin and others (2004).

Barren

[KE98-16C]

Sample ~80 ft below KE98-16B.

Brown, laminated dolostone and mudstone

(turbidites?). Thin section is dark, noncalcareous

mudstone with scattered siliceous sponge spicules

and rare, small, carbonate bioclast fragments.

3.2 kg of rock was processed.

10

PCA (Amaruk

plate)

De Long Mtns.

A-3

68°10'34.7"/

163°34'31.8"

2 Pa elements Polygnathus cf. Po. communis

Branson and Mehl (both partly covered with

adventitious quartz silt)

4 indet. bar, blade, and platform fragments

CAI=3

[79EK180C]

late Late Devonian-late Early

Mississippian (FamennianOsagean).

Indeterminate (too few

conodonts).

Sample from top of interval of shaly limestone.

Po. communis (as its name implies) is an extremely

common conodont throughout its range worldwide,

but is rare in samples of this age from the Red Dog

area.

Fossil loc. 25, Mayfield and others (1990).

19

PCA (Amaruk

plate)

De Long Mtns.

A-3

68°08’55.7"/

163°23'9.7"

8 Pa elements Bispathodus utahensis Sandberg and

Gutschick

6 juvenile Pa elements Gnathodus girtyi Hass?

1 Pa element Gnathodus cf. G. pseudosemiglaber

Thompson and Fellows

Hindeodus cristulus (Youngquist and Miller)

 10 Pa and 1 Pb elements

Unassigned elements:

 7 M (2 morphotypes), 1 Sa, 3 Sb (2 morphotypes)

& 4 Sc (3 morphotypes)

100 indet. bar, blade, and platform fragments

CAI=3.5

[8-17-83A; 29235-PC]

middle Late Mississippian

(late Meramecian) on the

basis of the conodonts in

this sample and in 8-17-

83B (loc. 20) (see

Remarks).

Mixed biofacies;

postmortem mixing of

conodonts from a

range of normalmarine shelf or

platform

environments.

Sample taken within 15 m of top of Lisburne Group

and 150 to 200 m stratigraphically above 8-17-83B

(loc. 20).

Medium-dark-gray, medium-light-gray-weathering,

very fine grained, massive dolostone interbedded

with laminated chert. Thin section is nonferroan,

slightly calcitic(?) dolostone; crystals 20 to 140 μm.

4.94 kg of rock was processed.

Sample collected by A.G. Harris.

Loc. 8 (fig. 2) of Dumoulin and others (2004).
Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic Creek allochthon—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector unless otherwise indicated: AD, J.A. Dumoulin; EK, I.

Ellersieck; JS, J.M. Schmidt; and KE, K. Evans. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

20

PCA (Amaruk

plate)

De Long Mtns.

A-3

68°08'49.8"/

163°23'18.4"

2 Pa elements Bispathodus utahensis Sandberg and

Gutschick

Cavusgnathus regularis Youngquist and Miller

 3 Pa and 1 M elements [pl. 1, fig. 26]

2 Sb-Sc elements Kladognathus sp. indet.

1 unassigned Sa element

40 indet. bar, blade, and platform fragments

CAI=3.5

[8-17-83B; 29236-PC]

middle Late Mississippian

(late Meramecian).

Indeterminate (too few

conodonts); species

association indicates

derivation from a

shallow and (or) midshelf or platform

environment.

Sample taken 150-200 m stratigraphically below 8-17-

83A (loc. 19) from sequence of thin- to mediumbedded dolostone, siliceous dolostone, and blueblack laminated chert.

Sampled 8-inch bed of medium-dark-gray, light-grayweathering, laminated, very fine grained dolostone.

Thin section is nonferroan, finely crystalline (20 to

150 μm) calcitic dolostone.

5.0 kg of rock was processed.

Sample collected by A.G. Harris.

Loc. 8 (fig. 2) of Dumoulin and others (2004).

34

PCA (Wulik

plate)

De Long Mtns.

B-2

68°21'54"/

162°50'30"

Barren

[KE98-24 (+10 ft)]

Part of a section of Lisburne Group originally

measured and sampled by K.Evans and A. Banet in

1998 and then remeasured and more extensively

sampled by J. Dumoulin and A. Harris in 1999 and

2000. *, position within section recalibrated by

Dumoulin and Harris. #, sample taken by Dumoulin

and Harris.

Sample taken ~10 ft above base of section and base of

Lisburne Group, which overlies Kayak Shale.

Large (1 x 3 m), light-brownish-gray-weathering

carbonate concretion(?) or slump block in thinbedded, silicified, dark-gray noncarbonate

mudstone. Thin section contains abundant

radiolarians in a matrix of darker (muddy?) finegrained carbonate (dolomite?). Most radiolarians

replaced by a single calcite crystal, but details of test

structure locally well preserved. Trace detrital quartz

and plagioclase.

6.2 kg of rock was processed.

Loc. 3 (app. 1) of Dumoulin and others (2004).
Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic Creek allochthon—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector unless otherwise indicated: AD, J.A. Dumoulin; EK, I.

Ellersieck; JS, J.M. Schmidt; and KE, K. Evans. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

34

PCA (Wulik

plate)

[Cont.]

De Long Mtns.

B-2

68°21'54"/

162°50'30"

Barren

[KE98-24 (+ 80 ft)]#

Sample taken ~80 ft. above base of measured section.

Pinkish-gray-weathering, dark-gray, 30- to 100-cmthick beds of laminated(?), blocky-weathering, finegrained calcareous radiolarite. Thin-section is

dolomitic calcareous radiolarite with lesser

calcareous spicules.

Heavy-mineral concentrate is chiefly composite

phosphatic carbonate rock fragments with minor to

common bioclasts (including phosphatized spicules

and spines, phosphatized steinkerns of ostracodes,

radiolarians, and spines, and phosphatic brachiopod

fragments). Radiolarian spines are abundant in the

<60 mesh heavy-mineral fraction.

11.0 kg of rock was processed.

1 Pa element Bispathodus utahensis Sandberg and

Gutschick

6 indet. bar, blade, and platform fragments

CAI=3

[KE98-24 (+210 ft); 33641-PC]#

Early, but not earliest,

Mississippian (late

Kinderhookian to at least

Osagean).

Indeterminate (too few

conodonts).

Sample taken ~210 ft. above base of measured section.

Medium-dark-gray, fine-grained, partly dolomitized

limestone containing probable small bioclasts.

Collected 20-cm-thick relatively chert free bed. Thin

section is bioturbated calcareous spiculite.

12.1 kg of rock was processed.

6 Pa elements Bispathodus utahensis Sandberg and

Gutschick [pl. 1, figs. 21, 22]

37 indet. bar, blade, and platform fragments

CAI=2 or 3

[KE98-24 (+308 ft); 33600-PC]*

Early, but not earliest,

Mississippian (late

Kinderhookian-Osagean).

Indeterminate (too few

generically

identifiable

conodonts); likely

postmortem transport

within or from a

bispathodid biofacies.

The conodonts and

associated spicules

and radiolarians

indicate a basinal

depositional setting.

Sample taken ~210 ft above base of measured section.

Very fine grained lime mudstone lens several meters

thick within black shale. Thin section is finely

interlaminated micrite and noncarbonate mud that

contain 30-50% sponge spicules (most calcareous,

some siliceous, some phosphatized), minor

calcareous and pyritized radiolarians, crinoid

ossicles, and quartz silt and sand.

Heavy-mineral concentrate is chiefly phosphatized

composite grains, phosphatized spicules, radiolarian

steinkerns, and minor pyrite and pyritizedphosphatized composite grains, spicules, and

radiolarians.

6.6 kg of rock was processed.
Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic Creek allochthon—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector unless otherwise indicated: AD, J.A. Dumoulin; EK, I.

Ellersieck; JS, J.M. Schmidt; and KE, K. Evans. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

34

PCA (Wulik

plate)

[Cont.]

De Long Mtns.

B-2

68°21'54"/

162°50'30"

1 indet. bar fragment

CAI=3

[KE98-24 (+273 ft); 33642-PC]#

Early, but not earliest,

Mississippian (late

Kinderhookian to at least

Osagean).

Indeterminate (too few

conodonts).

Sample taken ~273 ft above base of measured section.

Collected 20-cm-thick bed near top of prominent 15-ft

outcrop that becomes increasingly carbonate rich

upward. Medium-dark-gray, yellowish-grayweathering, fine-grained carbonate with probable

small bioclasts and millimeter-scale parallel

laminae. Thin section is calcareous spiculite with

lesser calcitized radiolarians.

Heavy-mineral concentrate includes rare phosphatized

pelmatozoan ossicles.

8.86 kg of rock was processed.

All conodonts are fragments

Kladognathus sp. indet.

 2 Pa-Pb, 4 M, 2 Sa, and 3 Sb-Sc elements

Hindeodus crassidentatus (Branson and Mehl)

 1 Pb, 2 M, 2 Sa, and 1 Sc elements [pl. 2, figs. 1,

2]

92 indet. bar, blade, and platform fragments

CAI=2.5-3

[KE98-24 (+382 ft); 33601-PC]*

Early, but not earliest

Mississippian (late

Kinderhookian to

Osagean).

Indeterminate (too few

generically

identifiable

conodonts);

postmortem transport

within or from a

shallow-water

depositional setting.

Sample taken ~275 ft above base of measured section.

Dolomitic(?) limestone beds, 25 to 30 cm thick. Thin

section is irregularly laminated, subhedral, finegrained dolomite(?) with siliceous and calcareous

sponge spicules, rare radiolarians and chert nodules;

some laminae are rich in peloids.

5.0 kg of rock was processed.

2 juvenile Pa elements Gnathodus sp. indet.

2 juvenile Pa elements Vogelgnathus cf. V.

pesaquidi Purnell and von Bitter [pl. 2, figs. 3, 4]

7 indet. bar, blade, and platform fragments

CAI=2.5-3

[KE98-24 (+360 ft); 33643-PC]#

Late Mississippian (early

Meramecian-middle

Chesterian).

Indeterminate (too few

conodonts); size of

conodonts suggests a

postmortem winnow

within or from a slope

or basin depositional

setting.

Sample taken ~360 ft above base of measured section,

at base of continuous thick carbonate-rich interval.

Medium-light-gray- and light-brownish-grayweathering, medium-dark-gray, very fine grained

limestone beds 2-10 cm thick with faint laminae and

chert layers parallel to bedding that make up 5-15%

of outcrop. Thin-section is calcareous spiculite with

siliceous nodules and lenses.

Heavy-mineral concentrate is chiefly phosphatic

brachiopod fragments.

10.9 kg of rock was processed.

Barren

[KE98-24 (+505 ft)]*

Sample taken ~380 ft above base of measured section.

Very fine grained lime mudstone in contorted beds;

may be a slump block. Thin section is finely

laminated calcareous spiculite with minor calcitized

radiolarians, peloids, and articulated ostracodes.

Heavy-mineral concentrate is chiefly fluorite.

6.2 kg of rock was processed.
Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic Creek allochthon—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector unless otherwise indicated: AD, J.A. Dumoulin; EK, I.

Ellersieck; JS, J.M. Schmidt; and KE, K. Evans. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

34

PCA (Wulik

plate)

[Cont.]

De Long Mtns.

B-2

68°21'54"/

162°50'30"

1 juvenile Pa element fragment Bispathodus

utahensis Sandberg and Gutschick

1 juvenile Pa element Cavusgnathus regularis

Youngquist and Miller [pl. 1, fig. 20]

2 M elements Kladognathus sp.

24 indet. bar, blade, and platform fragments

CAI=3

[KE98-24 (+590 ft); 33602-PC]*

middle Late Mississippian

(late Meramecian).

Indeterminate (too few

conodonts);

postmortem winnow

into quiet-water

(probably deep-water)

depositional setting.

Sample taken ~440 ft above base of measured section.

Top of measured section and close to top of Lisburne

Group. Fine-grained limestone. Thin section is

finely laminated calcareous spiculite with minor

calcitized radiolarians, peloids, and articulated

ostracodes.

6.0 kg of rock was processed.

35

PCA (Wulik

plate)

De Long Mtns.

B-2

68°21'56"/

162°49'54.5"

Conodonts are predominantly incomplete and

somewhat common within a large phosphatized

heavy-mineral concentrate.

early and middle Osagean conodonts:

 7 Pa elements Gnathodus cuneiformis Mehl and

Thomas [pl. 1, fig. 24]

Osagean-early Chesterian conodonts:

1 Pa element Gnathodus semiglaber Bischoff?

late Osagean-early Chesterian conodonts:

36 Pa elements (mostly fragments) Gnathodus

texanus Roundy [pl. 1, fig. 25]

18 Idioprioniodus sp. indet. fragments

early Chesterian conodonts:

 2 Pa elements Rhachistognathus prolixus

Baesemann and Lane [pl. 1, fig. 23]

Unassigned elements:

11 Pb elements (mostly fragments) of OsageanMeramecian morphotype

178 indet. bar, blade, and platform fragments

CAI=2.5

[99AD19D; 33481-PC]

No older than middle Late

Mississippian (early

Chesterian): mixture of

early-middle Osagean, late

Osagean-early Chesterian

conodonts.

Indeterminate; lag

concentrate

containing a mixture

of largely outer shelf

to off shelf conodonts

of mixed Osagean to

at least early

Chesterian age.

Samples stratigraphically highest carbonate bed in

Lisburne Group here; underlies grassy swale with

black silicified mudstone float (uppermost Lisburne

Group?) and then medium-gray-green radiolarian

chert (Etivluk Group). See table 14 for radiolarian

samples from the Etivluk at this locality. 99AD19D

is approximately equivalent to highest part of

measured section KE98-24 (loc. 34), which is 0.3

miles to southwest.

Very fetid limestone (crinoidal grainstone) with 3- to

4-mm-long black mudstone clasts; forms 0.5-mthick irregular outcrop with local black chert

nodules. Thin section is crinoidal grainstone with

bryozoan fragments and brachiopod(?) spines; many

bioclasts replaced (totally or in part) by phosphate.

Heavy-mineral concentrate is chiefly phosphatized

rock fragments (some ferruginous), phosphatized

bioclasts (including pelmatozoan fragments and

ostracode, gastropod, and pelecypod steinkerns) and

phosphatic brachiopod fragments.

8.6 kg of rock was processed.
Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic Creek allochthon—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector unless otherwise indicated: AD, J.A. Dumoulin; EK, I.

Ellersieck; JS, J.M. Schmidt; and KE, K. Evans. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

37

PCA (Wulik

plate)

De Long Mtns.

B-2

68°21'23"/

162°56'33.7"

2 Pa elements Gnathodus cuneiformis Mehl and

Thomas

1 Pa element Gnathodus sp. indet.

1 Pa element Eotaphrus burlingtonensis Pierce and

Langenheim [pl. 2, figs. 7, 8]

1 Pa element Polygnathus communis Branson and

Mehl [pl. 2, figs. 9, 10]

1 S element bar fragment Scaliognathus anchoralis

Branson and Mehl

60 indet. bar, blade, and platform fragments

CAI=2.5-3

[79EK184B; 27554-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralisDo. latus Zone).

Polygnathid biofacies;

postmortem transport

within or from a

shelfal depositional

setting.

Crinoidal limestone near contact with noncalcareous

cherts and shales.

8.2 kg of rock was processed.

Fossil loc. 13, Ellersieck and others (1990).

38

PCA (Wulik

plate)

De Long Mtns.

B-2

68°20'43.8"/

162°56'41.2"

2 "Hindeodella segaformis" Bischoff s.f. element

fragments

4 indet. bar and blade fragments

Conodonts are partly to substantially covered with

adventitious organic matter so that CAI is

approximate but not greater than 3.

[98AD11D; 33417-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralis-D,

latus Zone).

Indeterminate (too few

conodonts);

conodonts present

indicate relatively

deep-water

depositional setting,

probably a

postmortem winnow.

20-m-thick section of thin-bedded to laminated,

medium-gray, very fine grained limestone with

black to brown shale partings and thin chert

interbeds. Calcareous layers here are probable

turbidites. Thin section is 1- to 4-mm-thick layers of

calcisilt and fine-grained calcisand alternating with

0.5- to 1-mm-thick layers of brown lime mud;

scattered dolomite rhombs (60-100μm) especially in

muddy layers. Rare identifiable bioclasts mostly

calcareous and lesser siliceous spicules.

Heavy-mineral concentrate is chiefly angular to

subrounded green to blue-green mineral (glauconite

or zeolite?).

9.5 kg of rock was processed.

39

PCA (Amaruk

plate)

De Long Mtns.

B-2

68°17'28.5"/

163°11'52.9"

16 Pa elements (incomplete or fragments)

Bispathodus stabilis (Branson and Mehl) or

Bispathodus utahensis Sandberg and Gutschick

Kladognathus sp. indet.

 2 M, 1 Sa, and 2 Sb-Sc element fragments

1 unassigned M element fragment

61 indet. bar, blade, and platform fragments

CAI=2.5-3

[KE98-15B; 33502-PC]

Early, but not earliest,

through early Late

Mississippian (middle

KinderhookianMeramecian)

Postmortem transport

from or within the

bispathodid biofacies;

depositional setting

difficult to refine as

both single-row

bispathodids and

kladognathids were

likely surface

swimmers.

Light-gray-weathering, medium-light-gray, finegrained crinoidal dolostone, laminated and

interbedded with gray and tan chert. Outcrop

features suggest a distal ramp setting. Thin section is

dolostone with relict crinoid fragments.

Heavy-mineral concentrate includes very pale purple

fluorite.

3.3 kg of rock was processed.
Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic Creek allochthon—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector unless otherwise indicated: AD, J.A. Dumoulin; EK, I.

Ellersieck; JS, J.M. Schmidt; and KE, K. Evans. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

59

PCA (Amaruk

plate)

De Long Mtns.

A-2

68°11'24"/

163°8'13.1"

42 juvenile and subadult Pa elements Bispathodus

stabilis (Branson and Mehl) or Bi. utahensis

Sandberg and Gutschick

Kladognathus sp.

 18 M, 9 Sa, and 36 Sb-Sc elements

Unassigned elements:

 5 Pb (3 morphotypes), 7 M (3 morphotypes), 1

Sb, and 1 Sc

420 indet. bar, blade, and platform fragments

CAI=2.5-3

[98JS8G2; 33612-PC]

Early, but not earliest, to early

Late Mississippian (middle

KinderhookianMeramecian).

Postmortem transport

within or from the

bispathodidkladognathid

biofacies; deep-water

depositional setting.

Fine-grained, sucrosic, locally spiculitic, buff- to tanweathering dolostone interbedded with chert.

Dolostone in graded, locally contorted beds 1 to 2

cm thick that are probable turbidites. Thin section is

fine-grained euhedral dolomite mosaic with trace

detrital quartz silt and sand and local phosphatic(?)

laminae.

Heavy-mineral concentrate consists chiefly of

phosphatized composite grains.

5.8 kg of rock was processed.

117

PCA (Wulik

plate)

Misheguk Mtn.

B-5

68°21'54"/

161°46'15"

All conodonts are robust fragments reflecting the

high-energy derivation of their host rock.

6 Idioprioniodus sp. indet. robust fragments

10 incomplete Pa elements Pseudopolygnathus

oxypageus Lane, Sandberg, and Ziegler

36 Pa elements Pseudopolygnathus spp. indet.

 1 unassigned M elements

31 indet. bar, blade, and platform fragments

CAI=~2.5

[00AD25A; 33636-PC]

late Early Mississippian (late

early-middle Osagean;

Upper G. typicus Zone

through lower 2/3 of

succeeding Sc. anchoralisDo. latus Zone).

Postmortem transport

from or within the

pseudopolygnathid

biofacies; postmortem

transport within or

from an outer shelf or

slope depositional

setting.

Medium-gray- and pale yellow-brown-weathering,

medium-dark-gray, pelmatozoan grainstone from

0.5-3 cm thick beds above and below thicker chert

layers. Chert beds contain abundant silicified

pelmatozoan ossicles. Thin-section is a diverse

skeletal supportstone; bioclasts include crinoids,

brachiopods, ostracodes, and foraminifers.

Heavy-mineral concentrate is chiefly dolomitized

bioclasts (predominantly pelmatozoan ossicles and

rare phosphatized fenestrate bryozoan fragments)

and minor fluorite.

13.1 kg of rock was processed.

Loc. 4 (app. 1) of Dumoulin and others (2004).
Table 4. Conodont samples from deep-water facies of the Lisburne Group in the Picnic Creek allochthon—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector unless otherwise indicated: AD, J.A. Dumoulin; EK, I.

Ellersieck; JS, J.M. Schmidt; and KE, K. Evans. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

117

PCA (Wulik

plate)

[Cont.]

Misheguk Mtn.

B-5

68°21'54"/

161°46'15"

5 Pa element fragments Bispathodus utahensis

Sandberg and Gutschick?

Kladognathus tenuis

 3 Sa, 5 Sb-Sc

3 juvenile Pa elements Polygnathus communis

Branson and Mehl

1Sc and 35 S element bar fragments (short and

long) Scaliognathus anchoralis Branson and

Mehl [pl. 2, figs. 5, 6]

1 juvenile Pa element Synclydognathus geminus

(Hinde)

Unassigned elements:

 7 Pb (5 morphotypes), 7 M (5 morphotypes), 3

Sa, and 2 Sc (2 morphotypes)

145 indet. bar, blade, and platform fragments

CAI=2

[00AD25F; 33637-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralisDo. latus Zone).

Post-mortem transport

(likely a winnow)

from a mix of outer

shelf and slope

environments.

Float block on talus slope at same general locale as

00AD25A.

Block 40 x 10 cm of light-gray-weathering, pinkishmedium-dark-gray, fine-grained limestone and black

chert in 2-cm alternations. Limestone partly

silicified. Thin-section is calcareous spiculite with

rare radiolarians; some spicules pyritized.

Heavy-mineral concentrate includes composite

phosphatic, very fine grained siliciclastic rock

fragments and rare sponge spicules.

7.7 kg of rock was processed.
Table 5. Conodont samples from other deep-water strata of the Lisburne Group

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; IRA, Ipnavik River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

and AK, J.S. Kelley. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional environment

Remarks

85

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°01'31"/

162°48'12"

1 deformed incomplete Pa element Bispathodus

stabilis (Branson and Mehl) or Bi. utahensis

Sandberg and Gutschick

1 unassigned M element

1 indet. blade or platform fragment

CAI=3

[97AK1A; 33392-PC]

Early Mississippian

(Kinderhookian-Osagean).

Indeterminate (too few

conodonts).

Sample from section of unnamed deep-water facies

underlying the Kogruk Formation.

Sample from ~5 m of dark-gray to black chert and

cherty carbonate in nodular beds 1 to 5 cm thick

that may be partly bioturbated; overlies ~7 m of

dark shale and mudstone. Thin section is dolomite

rhombs and rhombohedral clusters 60 to 500 μm

in diameter in a black organic-rich matrix with a

1-cm-thick lens of brown spiculitic chert.

7.0 kg of rock was processed.

89

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°00'25"/

162°48'22.6"

2 Pa elements Cavusgnathus unicornis Youngquist

and Miller

4 Pa elements Gnathodus sp. indet.

1 Sc element Kladognathus tenuis

Unassigned elements:

 3 Pb (2 morphotypes) and 1 Sc

48 indet. bar, blade and platform fragments

CAI=2 or 3 (nearly all conodonts covered with or

invaded by organic material)

[98AD13A; 33418-PC]

middle-late Late

Mississippian (late

Meramecian-Chesterian).

Indeterminate (too few

conodonts). The

cavusgnathids are very

large fragments compared

to the rest of the

conodont fauna and

indicate postmortem

transport from a shallowwater environment; the

relatively large number of

indeterminate fragments

also indicates postmortem

transport. Two of the

gnathodids are complete,

suggesting they lived

nearby in a middle shelf

or deeper water

depositional setting.

Sample from section of unnamed deep-water facies

depositionally underlying the Kogruk Formation.

Sample from 0.5 m of dark-gray to black, lightgray-weathering, very fine grained limestone in 1

to 4-cm-thick beds, above 4 m of thinner bedded,

beige, shaly limestone and overlain by brownish

black shale and mudstone. Thin section is very

fine-grained skeletal packstone made up chiefly of

calcareous sponge spicules (20 x 400 μm or less)

and lesser calcitized radiolarians (test structure

locally well-preserved).

9.7 kg of rock was processed.

Loc. 21 (fig. 2) of Dumoulin and others (2004).

120

IRA (Nachralik

Pass plate)

Misheguk Mtn.

B-4

68°27'47"/

161°20'7.8"

Bispathodus utahensis Sandberg and Gutschick

 27 Pa (mostly fragments) and 3 Pb elements

1 incomplete P element Geniculatus sp. [fig. 2,

figs. 11, 12]

1 bar fragment Scaliognathus anchoralis Branson

and Mehl

Unassigned elements:

 5 Pb (4 morphotypes), 2 M (2 morphotypes), 1 Sb,

and 5 Sc (3 morphotypes)

192 indet. bar, blade, and platform fragments

CAI=2.5-3

[00AD26A; 33638-PC]

middle late Early

Mississippian (middle

Osagean; Sc. anchoralisDo. latus Zone).

Postmortem transport

within or from the

bispathodid biofacies;

transport from a shelf and

(or) slope depositional

setting.

Sample from very fine grained, light-grayweathering, pinkish medium-gray dolostone layer,

~0.5 to 1 m thick, that forms notable recessive

interval in outcrop of black chert. Dolostone beds

are 1 to 6 cm thick and parallel- and crosslaminated. Thin section is dolomitic calcareous

radiolarite.

Heavy-mineral concentrate includes minor

dolomitized bioclasts.

9.0 kg of rock was processed.

Loc. 5 (app. 1) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

2

KRA (Chimney

plate)

De Long Mtns.

A-4

68°11'14.3"/

163°56'6.5"

Virtually all specimens are severely broken or

incomplete.

14 Pa element fragments Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg

and Gutschick

Kladognathus sp.

 2 Pa-Pb, 6 M, 1 Sa, and 11 Sb-Sc elements

Synclydognathus geminus (Hinde)

 3 Pa and 9 M & S elements

1 unassigned ozarkodinid Sc element

204 indet. bar, blade, and platform fragments

CAI=2

[99AD26AA; 33482-PC]

Early-middle Late

Mississippian (middle

Kinderhookian-early

Chesterian, probably no

younger than Meramecian).

Postmortem transport

within or from the

kladognathidbispathodid biofacies;

species association

and taphonomy

indicates a relatively

high-energy shallowwater depositional

environment.

Sample near base of cherty limestone member of

Kogruk Formation of Mayfield and others (1990)

from 0.5-m-thick interval with no chert bounded by

irregular white chert bands; outcrop contains local

silicified bryozoans and horn corals.

Massive, very light gray-weathering, pinkish-gray,

slightly fetid, sugary calcareous dolostone with

abundant crinoid ossicles. Thin section is partly

dolomitized crinoidal supportstone.

Heavy-mineral concentrate includes phosphatized

bioclasts (bryozoans) and phosphatic bioclasts

(phosphatic brachiopod fragments and ichthyoliths).

9.5 kg of rock was processed.

3

Olistolith,

possibly

derived from

KRA

De Long Mtns.

A-4

68°06'18"/

164°06'24"

1 subadult Pa element Gnathodus sp. of late

Osagean-early Chesterian morphotype

1 Sb-Sc element fragment Kladognathus sp. indet.

3 indet. bar, blade, and platform fragments

CAI=1.5-2

[79MD180; 27567-PC]

latest Early-middle Late

Mississippian (late

Osagean-early Chesterian).

Indeterminate (too few

conodonts).

Conodonts indicate

normal-marine

shallow-shelf to slope

environment.

Limestone.

Fossil loc. 32, Mayfield and others (1990).

5

KRA (Wulik

Peaks plate)

De Long Mtns.

B-3

68°17'37"/

163°22'04"

7 indet. bar, blade, and platform fragments

CAI difficult to determine as all conodonts are

worn fragments; >2 to 3.5-4.

[00AD4B; 33625-PC]

Mississippian on the basis of

stratigraphic position and

stratigraphic unit.

Indeterminate; no

generically

identifiable

conodonts.

Near top of Kogruk Formation here; sample from

highest carbonate rock overlain by ~3 m of recessive

black shale that contains radiolarian-bearing

phosphate nodules 3 to 4 cm in diameter. Etivluk

Group chert overlies Kogruk; see table 14 for

Etivluk radiolarian faunas from this locality.

Light-gray-weathering, medium- to medium-lightgray, thick- to massive-bedded limestone with 10-

15% chert; grainstone/packstone with large bioclasts

including pelmatozoan ossicles and solitary corals.

Thin-section is pelmatozoan-bryozoan packstone

with ostracodes, brachiopod fragments, calcareous

sponge spicules, and a trace of quartz silt; silica

partly replaces some bioclasts. Fabric is packed to

overpacked with some sutured contacts.

Heavy-mineral concentrate includes phosphatized rock

fragments and bioclasts and minor ichthyoliths.

10.55 kg of rock was processed.

Loc. 1 (fig. 2) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

6

KRA (Wulik

Peaks plate)

De Long Mtns.

B-3

68°18'19.2"/

163°19'25"

3 well preserved Pa elements Bispathodus

utahensis Sandberg and Gutschick

1 large posterior Pa element fragment

Cavusgnathus sp. indet.

Kladognathus sp.

 2 M and 2 Sb-Sc elements

Synclydognathus geminus (Roundy)

 1 Sb and 1 Sc elements

11 indet. bar, blade, and platform fragments

CAI=3

[79MD146D; 27556-PC]

 middle Late Mississippian

(late Meramecian).

Indeterminate (too few

conodonts); likely a

mix of shallow- and

deeper-water taxa.

Fossil loc. 29, Mayfield and others (1990).

8

KRA (?Wulik

Peaks plate)

De Long Mtns.

A-3

68°13'43.5"

163°13'01.2"

1 incomplete Pa element Bispathodus utahensis

Sandberg and Gutshick 

1 anterior Pa element fragment Cavusgnathus sp.

indet.

2 incomplete Pa element fragments Hindeodus spp.

27 Pa elements Gnathodus homopunctatus Ziegler

30 Pa elements Gnathodus texanus Roundy

Synclydognathus geminus Hinde

 5 Pa, 2 Pb, and 16 S elements

Unassigned elements:

 3 Pb (2 morphotypes) and 2 Sa (2 morphotypes)

158 indet. bar, blade, and platform fragments

CAI=2

[04AD39A; 33784-PC]

middle Late Mississippian

(late Meramecian-very

early Chesterian; Lower

Cavusgnathus Zone into

succeeding Gn. bilineatusUpper Cavusgnathus Zone).

Postmortem transport

from a gnathodid

biofacies. Outer shelf

or deeper water

depositional

environment

Sample taken from uppermost well-exposed Lisburne

Group, underlying Etivluk Group and Okpikruak

Formation (Mayfield et al., 1990).

Sample from upper 30 cm of exposure, consists of

light-gray-weathering, medium-gray limestone with

sparse glauconite (skeletal grainstone with crinoids

and brachiopods) in 10- to 30-cm-thick beds.

Interval contains <10% blackish brown, irregular

chert (replacing burrows?); upper part appears to be

bored.

Heavy-mineral concentrate is paleontologically diverse

and contains more than 95% phosphatic and

phosphatized bioclasts (in order of decreasing

abundance: crinoid columnals and ossicles;

phosphatized ostracode, gastropod, and bivalve

steinkerns; phosphatic brachiopod fragments;

ichthyoliths; and phosphatized bryozoan fragments)

and rare glauconite.

6.0 kg of rock was processed

21

KRA (Chimney

plate)

De Long Mtns.

A-3

68°08'39.2"/

163°23'13"

2 Pa element fragments Polygnathus sp. indet. of

Middle Devonian-Early Mississippian

morphotype

1 M (apatognathiform) element of Famennian-early

Chesterian morphotype

8 indet. bar, blade, and platform fragments

CAI=3.5

[8-17-83C]

late Late Devonian-Early

Mississippian (FamennianOsagean).

Indeterminate (too few

conodonts).

Kogruk Formation(?); collected near structural base of

thrust sheet. Dark-gray, thick-bedded micrite. Thin

section is fine-grained pelloidal-skeletal

grainstone/packstone; bioclasts include crinoids,

brachiopods, and ostracodes, as well as notable

calcispheres and girvanellid and other algae.

5.34 kg of rock was processed.

Sample collected by A.G. Harris.
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

22

KRA (Chimney

plate)

De Long Mtns.

A-3

68°08'30"

163°23'12"

1 Pa element fragment Bispathodus utahensis

Sandberg and Gutschick

1 Pa element Cavusgnathus sp.

Unassigned elements:

 1 Pb, 1 M, and 1 Sb

9 indet. bar, blade, and platform fragments

CAI=3.5

[8-17-83D; 29237-PC]

probably middle Late

Mississippian (late

Meramecian-early

Chesterian(?), probably late

Meramecian).

Indeterminate (too few

conodonts).

Medium-dark-gray, light-gray-weathering, very fine

grained, slightly dolomitic limestone and chert

(limestone 60%, chert 40%); ~50-100 ft above 8-17-

83C (loc. 21). Thin section is fine-grained pelloidal

calcisiltite; bioclasts include calcispheres, calcareous

spicules, rare crinoids, and ostracodes. Minor

scattered dolomite rhombs; trace quartz (and

feldspar?) silt along stylolites.

5.04 kg of rock was processed.

Sample collected by A.G. Harris.

2 Pa elements Bispathodus utahensis Sandberg and

Gutschick

Cavusgnathus sp. indet.

 1 Pa and 1 M elements

1 Pb element Synclydognathus sp. indet.

Unassigned elements:

 1 Sa and 1 Sc

17 indet. bar, blade, and platform fragments

CAI=3

[8-17-83E; 29238-PC]

probably middle Late

Mississippian (late

Meramecian-early

Chesterian(?), probably late

Meramecian).

Indeterminate (too few

conodonts); probably

shallow to moderate

depth shelf or

platform.

Sample taken a few hundred ft SE of 8-17-83D.

Massive, cliff-forming medium-gray, laminated,

siliceous limestone. Cliff is 80% blue-black chert

and 20% siliceous limestone. Thin section is

calcareous sponge spicule-pelloid packstone with

rare crinoid ossicles and radiolarians(?) and a trace

of quartz (and feldspar?) silt.

6.64 kg of rock was processed.

Sample collected by A.G. Harris.

23

KRA (Chimney

plate)

De Long Mtns.

A-3

68°07'44.6"/

163°23'25.2"

6 indet. bar, blade, and platform fragments

CAI=4

[8-17-83F]

Silurian-Permian Indeterminate (too few

conodonts).

Dark-gray, fine-grained, crudely bedded limestone that

does not contain chert. Thin section is skeletalpelloidal packstone with diverse bioclasts, including

crinoid and brachiopod fragments, ostracodes,

foraminifers, and various algae; trace quartz and

feldspar silt.

6.26 kg of rock was processed.

Sample collected by A.G. Harris.

32

KRA (Wulik

Peaks plate)

De Long Mtns.

A-3

68°00'20.5"/

163°15'19.5"

1 Pa element Cavusgnathus unicornis Youngquist

and Miller

1 S element fragment Synclydognathus sp. indet.

10 indet. bar, blade, and platform fragments

CAI=2.5

[79TR142; 27595-PC]

middle Late Mississippian

(late Meramecian-early

Chesterian).

Indeterminate (too few

conodonts).

Conodonts indicate

shallow-water, near a

restricted or

intermittently

restricted depositional

setting.

Fossil loc. 20, Mayfield and others (1990).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

40

KRA (Wulik

Peaks)

De Long Mtns.

B-2

68°16'20.3"/

163°11'10.7"

4 Pa elements Bispathodus utahensis Sandberg and

Gutschick

1 Pa element Cavusgnathus unicornis Youngquist

and Miller

2 posterior Pa element fragments Cavusgnathus sp.

indet.

1 Pa element fragment Hindeodus sp. indet. or

Synclydognathus sp. indet.

5 Sb-Sc elements Kladognathus tenuis (Branson

and Mehl)

29 indet. bar, blade, and platform fragments

CAI=3

[KE98-14D1; 33499-PC]

 middle Late Mississippian

(late Meramecian).

Indeterminate (too few

generically

identifiable

conodonts).

Conodonts present

indicate postmortem

transport within or

from a shallow-water

depositional

environment.

Float sample from lower part of Kogruk Formation(?);

see table 7 for Utukok Formation sample from this

locality.

Medium-gray-weathering, medium-dark-gray

limestone; crinoid-coral pack/wackestone. Thin

section is poorly sorted skeletal pack/wackestone

with trace quartz silt. Bioclasts consist of 30-50%

crinoid ossicles, 5-15% foraminifers, and lesser

algae, ostracodes, and bryozoan fragments.

Heavy-mineral concentrate includes phosphatized

bioclasts and rare ichthyoliths.

3.9 kg of rock was processed.

2 Pa element fragments Bispathodus utahensis

Sandberg and Gutschick

1 Pa fragment of a cavusgnathid

Kladognathus sp. indet.

 1 Sa and 3 Sc element fragments

4 indet. bar and blade fragments

CAI=3

[KE98-14D2; 33500-PC]

late Early-middle Late

Mississippian (late

Osagean-Meramecian).

Indeterminate (too few

conodonts);

postmortem transport

within or from a

relatively shallowwater depositional

setting.

Outcrop sample, lower part of Kogruk Formation.

Limestone with irregular chert lenses and local

syringoporid corals. Thin section is crinoidal

packstone with notable foraminifers and lesser algae,

ostracodes, bryozoan fragments, and calcispheres.

Heavy-mineral concentrate consists chiefly of coarsely

phosphatized bioclasts (including pelmatozoans,

spine steinkerns, and bryozoans).

4.32 kg of rock was processed.

42

EMA

(Wolverine

Creek plate;

Mt. Raven

window)

De Long Mtns.

A-2

68°13'28.2"/

162°50'28.4"

6 Pa elements Gnathodus bilineatus (Roundy)

(early form)

49 Pa (juveniles to adults) elements Gnathodus

pseudosemiglaber Thompson and Fellows

Gnathodus sp. indet.

 4 Pb, 5 M, 2 Sa, and 3 Sc elements

7 Idioprioniodus sp. indet. element fragments

Lochriea commutata (Branson and Mehl)

 18 Pa (all juveniles to subadults) and 18 M

elements

1 M element Kladognathus sp. indet.

311 indet. bar, blade, and platform fragments

CAI=4

[99AD13I; 33480-PC]

middle Late Mississippian

(late Meramecian-early

Chesterian).

Postmortem transport

within the gnathodidlochrieid biofacies;

conodonts indicate a

slope depositional

setting.

Sample from stratigraphically highest carbonate bed in

Lisburne Group here, which underlies several meters

of black chert (uppermost Lisburne), which underlies

white-weathering radiolarian chert (basal Siksikpuk

Formation).

Carbonate layer is 1 m thick, medium dark gray, very

light gray to pinkish gray weathering, fine grained,

very fetid, and contains possible peloids. It forms

uneven 15 to 20 cm-thick beds with nodules of black

vitreous chert to 60 cm long. Thin section is organicrich, fine-grained, euhedral dolomite(?) mosaic, with

rare bioclasts.

Heavy-mineral concentrate includes phosphatized

peloids(?) and composite phosphatized grains, as

well as lesser phosphatized steinkerns of gastropods,

ostracodes, pelecypods, and spines.

11.4 kg of rock was processed.

Loc. 4 (fig. 2) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

43

EMA

(Wolverine

Creek plate;

Mt. Raven

window)

De Long Mtns

A-2

68°13'18"/

162°44'18"

Barren

[KS98-105]

Sample submitted as Utukok Formation(?) but facies

and position suggest upper part of Kogruk

Formation. Strata are ~10 m south of Etivluk Group;

contact between the two units may be a fault.

Rusty-brown dolomite or impure limestone

interbedded with dark-gray shale. Thin section is

cherty fine-grained dolomitic limestone with rare

radiolarians (some filled with chalcedony, others

with carbonate) and calcareous and siliceous

spicules.

12.2 kg of rock was processed.

44

EMA

(Wolverine

Creek plate;

Mt. Raven

window)

De Long Mtns.

A-2

68°12'35.9"/

162°52'48"

Barren

[KE98-27]

Light-gray dolostone. Thin section is finely crystalline

euhedral/subhedral dolomite mosaic with ~10%

quartz that occurs between crystals and fills vugs and

rare molds of crinoid ossicles. Some vugs contain

dead oil.

Heavy-mineral concentrate includes indeterminate

phosphatized bioclasts.

2.94 kg of rock was processed.

45

EMA

(Wolverine

Creek plate;

Mt. Raven

window)

De Long Mtns.

A-2

68°12'30"

162°53'32"

Cavusgnathus sp. indet.

 1 M and 3 Pa element fragments

1 Sc element Hindeodus sp. indet.

Kladognathus sp.

 3 M and 3 Sb-Sc elements

Synclydognathus geminus (Hinde)

 3 Pa, 1 M, 1 Sa, and 1 Sb elements

74 chiefly small indet. bar, blade, and platform

fragments

CAI=3

[98AD9A; 33415-PC]

middle Late Mississippian

(late Meramecian-early

Chesterian).

Indeterminate (too few

conodonts).

Postmortem mixture

of species

representing shallowwater, near restricted

depositional setting.

Sample taken several hundred feet stratigraphically

below top of Kogruk Formation.

Subcrop of massive, light-gray, crinoidal dolostone

(packstone/grainstone) with irregular stringers of

black chert. Thin section is dolostone (crystals 20

μm to >1 mm, most 100-200 μm) with relict

pelmatozoan fragments 1 to 7 mm in diameter;

abundant vugs (1 to 4 mm), some of which look like

molds of crinoid ossicles.

10.3 kg of rock was processed.

Loc. 5 (fig. 2) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

46

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°13'38"/

163°04'14.2"

3 juvenile Pa elements Cavusgnathus unicornis

Youngquist and Miller

1 juvenile Pa element Gnathodus texanus Roundy

2 Sb elements Synclydognathus sp. indet.

Unassigned elements:

 2 Pb, 2 M (2 morphotypes), 1 Sa, and 2 Sc (two

morphotypes)

CAI=3

[8-16-83D; 29230-PC]

middle Late Mississippian

(late Meramecian-early

Chesterian).

Indeterminate (too few

conodonts and mixed

biofacies).

Medium-gray, fine- to medium-grained, medium- to

thick-bedded, bioclastic, bioturbated wackestone

containing ~20-30% chert. Thin section is

overpacked, skeletal-pelloidal packstone; bioclasts

(80% of grains) include pelmatozoan, bryozoan, and

brachiopod fragments and articulated ostracodes.

Minor nonferroan dolomite and detrital quartz silt.

6.4 kg of rock was processed.

Sample collected by A.G. Harris.

56

KRA (Wulik

Peaks)

De Long Mtns.

A-2

68°11'34.5"/

163°10'0.8"

1 Sa element Kladognathus sp. indet.

1 unassigned robust digyrate Sc element

1 indet. bar fragment

CAI=2.5

[KE98-13; 33498-PC]

Mississippian Indeterminate; too few

conodonts.

Near top of Kogruk Formation here. See table 7 for

Utukok Formation sample from this locality.

Medium-gray limestone with crinoid ossicles. Thin

section is skeletal supportstone with locally

dolomitized matrix; bioclasts include pelmatozoan,

bryozoan, ostracode, and brachiopod fragments,

foraminifers, and diverse algae.

Heavy-mineral concentrate is chiefly phosphatized

rock fragments and minor bioclasts, ichthyoliths, and

anhedral pyrite and chalcopyrite.

6.1 kg of rock was processed.

58

KRA?

De Long Mtns.

A-2

68°11'27.6"/

163°08'24"

1 indet. bar fragment

CAI=3

[98JS8E; 33611-PC]

Mississippian Indeterminate (too few

conodonts).

Undolomitized Kogruk Formation. Thin section is

fine-grained skeletal grainstone with foraminifers,

algae, crinoid ossicles and articulated ostracode

valves.

5.8 kg of rock was processed.

60

KRA (Wulik

Peaks)

De Long Mtns.

A-2

68°11'09"/

163°11'19.5"

6 juvenile Pa elements Gnathodus

pseudosemiglaber Bischoff

8 juvenile or fragmentary Pa elements Gnathodus

sp. indet.

Unassigned elements:

 1 Sa and 2 Sc

92 small indet. bar, blade, and platform fragments

CAI=3

[KE98-12; 33497-PC]

late Early-middle Late

Mississippian (middle

Osagean-Meramecian;

middle Sc. anchoralis-Do.

latus Zone through

Meramecian).

Indeterminate (too few

generically

identifiable

conodonts).

Conodonts present

suggest postmortem

winnow in an openmarine setting.

Top of Kogruk Formation here.

Light-gray-weathering, medium-light-gray, finegrained limy dolostone. Thin section is dolomitic

crinoid wacke/packstone; some crinoids are still

calcite, but others are replaced by silica.

Heavy-mineral concentrate includes minor phosphatic

brachiopod fragments and rare ichthyoliths.

5.8 kg of rock was processed.
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

62

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°10'51"/

163°10'25.6"

1 juvenile Pa element Cavusgnathus unicornis

Youngquist and Miller

2 indet. bar and blade fragments

CAI=4?

[98JS7K; 33609-PC]

Late, but not earliest Late

Mississippian (late

Meramecian-Chesterian).

Indeterminate (too few

conodonts).

Top of Kogruk Formation here. See tables 7 and 9 for

additional samples from this locality.

Light-gray limestone. Thin section is coarse-grained,

packed, skeletal grainstone; main bioclasts are

crinoid ossicles, bryozoans, and brachiopod

fragments with lesser articulated, thick-shelled

ostracodes and trace quartz and plagioclase feldspar

silt.

Heavy-mineral concentrate includes phosphatized

composite grains, peloids, and bioclasts.

5.7 kg of rock was processed.

68

EMA

(Wolverine

Creek plate;

Mt. Raven

window)

De Long Mtns.

A-2

68°10'42"/

162°41'12"

2 unassigned Sc element fragments (2

morphotypes)

11 indet. bar, blade, and platform fragments

CAI=3

[KS98-90; 33607-PC]

Post-Ordovician Paleozoic Indeterminate (too few

conodonts).

Sample near base of Kogruk Formation, which is here

thrust above Etivluk Group.

Medium- to medium-light-gray, finely laminated

dolostone (40%) and black chert (60%) in even beds

2 to 3 cm thick. Thin section is finely crystalline

euhedral to subhedral dolomite mosaic with rare

relict crinoid ossicles(?).

6.82 kg of rock was processed.

69

KRA (Kelly

plate)

De Long Mtns.

A-2

68°09'41"

162°45'10"

5 Pa element fragments Cavusgnathus unicornis

Youngquist and Miller

Hindeodus sp. indet.

 3 Pa and 1 Sa elements (all fragments)

1 Sb-Sc element Kladognathus sp. indet.

48 indet. bar, blade, and platform fragments

CAI=2.5-3

[98AD6E; 33414-PC]

middle-late Late

Mississippian (late

Meramecian-Chesterian).

Indeterminate (too few

conodonts).

Conodont fragments

present indicate

derivation from a

shallow-water

depositional

environment.

Near contact with Utukok Formation as mapped by

Ellersieck and others (1990); probably in lower third

of Kogruk Formation.

Massive, light-gray-weathering, medium-dark-gray

limestone with scattered fossils (mostly crinoids) and

20-30% chert. Thin section is peloidal-skeletal

packstone to grainstone with minor detrital quartz

sand and abundant stylolites and fractures; many

bioclasts are micritized.

8.9 kg of rock was processed.

73

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°07'00"/

163°08'36"

5 Pa elements Gnathodus pseudosemiglaber

Thompson and Fellows

21 Pa elements Gnathodus texanus Roundy

13 Pa element fragments Gnathodus spp.? indet.

1 Pa element fragment Rhachistognathus prolixus

Baesemann and Lane

202 indet. bar, blade, and platform fragments

CAI=2.5

[KE98-25A; 33603-PC]

Likely middle Late

Mississippian (very early

Chesterian).

Postmortem transport

from or within the

gnathodid biofacies.

Outer shelf or deeper

water depositional

environment.

Uppermost Kogruk Formation; see table 7 for Utukok

Formation sample from this locality.

Sample from top of cliff. Partly dolomitized skeletal

grainstone interbedded with black chert. Thin section

is euhedral/subhedral dolomite mosaic with as much

as 30% quartz that occurs between crystals and fills

vugs and rare molds of crinoid ossicles. Some vugs

contain dead oil.

Heavy-mineral concentrate includes dolomitized and

phosphatized composite grains and bioclasts

(bryozoans and pelmatozoans).

5.1 kg of rock was processed.

Loc. 14 (fig. 2) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

73

EMA

(Wolverine

Creek plate;

Rok window)

[cont.]

De Long Mtns.

A-2

68°07'00"/

163°08'36"

Kladognathus sp.

 6 M, 1 Sa, and 16 Sb-Sc elements

7 Pa elements Polygnathus mehli Thompson [pl. 2,

figs. 14, 15]

Synclydognathus geminus (Hinde)

 2 Pa and 5 M and S elements (chiefly fragments)

Unassigned elements:

 2 Pb (2 morphotypes) and 2 Sc (2 morphotypes)

26 indet. bar, blade, and platform fragments

CAI=3

[KE98-25B; 33604-PC]

late Early Mississippian (late

middle-earliest late

Osagean; uppermost Sc.

anchoralis-Do. latus Zone

into succeeding earliest Po.

mehli-Lower Gn. texanus

Zone).

Postmortem transport

from or within the

kladognathidpolygnathid biofacies.

Shelfal depositional

setting.

Sample taken at base of cliff, ~220 ft below KE98-

25A.

Light-gray-weathering, medium-gray limestone with

crinoid ossicles and local corals. Thin section is

skeletal packstone with dolomitized matrix; bioclasts

include pelmatozoans, bryozoans, and lesser

brachiopods, ostracodes, algae, foraminifers, and

calcareous spicules.

Heavy-mineral concentrate includes dolomitized

indeterminate bioclasts, rare phosphatic brachiopod

fragments, and ichthyoliths.

3.7 kg of rock was processed.

75

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°05'54"/

163°06'57"

Conodonts are mostly fragments—breakage is

mainly due to brittle deformation and is not

depositional.

11 Pa elements Cavusgnathus unicornis

Youngquist and Miller

6 largely incomplete Pa elements Hindeodus

minutus (Ellison)

Kladognathus tenuis

 2 Pa-Pb (fragments), 7 M, 14 Sb-Sc elements

20 Pa elements Rhachistognathus prolixus

Baesemann and Lane

Synclydognathus geminus (Hinde)

 11 Pa and 12 S and M elements

Unassigned elements:

 4 M (3 morphotypes) and 1 Sa

236 indet. bar, blade, and platform fragments

CAI=3.5-4

[00AD21A; 33632-PC]

middle Late Mississippian,

(very early Chesterian).

Synclydognathidcavusgnathid

biofacies; shallowwater, near highenergy depositional

setting.

About 10 m below top of Kogruk Formation at

stratigraphic contact with Siksikpuk Formation.

Light-gray- to very light gray-weathering, mediumgray and pinkish-gray, massively bedded, finely to

moderately sucrosic cherty dolostone in beds 0.7 to 1

m thick; chert randomly distributed in irregular

masses 10 to 30 cm in size. Some areas

autobrecciated. Part of large continuous section

along cutbank of Wulik River. Thin section is

dolostone with relict crinoid ossicles.

Heavy-mineral concentrate contains phosphatized

bioclasts (including phosphatized pelmatozoan

ossicles, gastropod steinkerns, bryozoan zooecial

fillings, and spines) and phosphatic bioclasts

(ichthyoliths).

11.5 kg of rock was processed.

Loc. 15 (fig. 2) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

82

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°01'30"/

163°0l'48"

2 Pa element fragments Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg

and Gutschick

4 Pa element fragments Bispathodus sp. indet.

(double-row)

1 unassigned M element

19 indet. bar, blade, and platform fragments

CAI=3.5-4

[8-15-83B; 29227-PC]

late Late Devonian- early

Early Mississippian (late

Famennian-Kinderhookian)

Indeterminate (too few

conodonts); conodonts

derived from a

normal-marine,

probably shallowwater depositional

setting.

Upper part of Kogruk Formation. Age atypically old

for Kogruk; conodonts may have been reworked

from underlying older rocks.

Medium-gray to light-brownish-gray, light-grayweathering, siliceous, very fine grained, laminated

dolostone with massive replacement chert. Thin

section is nonferroan dolostone (crystals 20-200 μm)

with a cherty zone rich in siliceous sponge spicules

and radiolarians(?). Some dolomite rhombs replaced

by silica.

7.9 kg of rock was processed.

Sample collected by A.G. Harris.

84

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°00'34.6"

162°59'49"

Kladognathus sp. indet.

 3 M, 2 Sa, and 4 Sb-Sc elements

1 Pb and 1 Sb unassigned elements

53 indet. bar, blade, and platform fragments

6 ichthyoliths

CAI=3-3.5

[98AD15A; 33420-PC]

Mississippian, but not very

earliest Mississippian

(middle KinderhookianChesterian).

Indeterminate (too few

conodonts).

Conodonts present

suggest shallow-water

depositional setting.

Sample from Kogruk Formation, stratigraphically

above Utukok Formation sample 98AD14G (loc. 83,

table 7).

Six-meter-thick section (sample near base) of lightgray-weathering, grayish-black, fetid limestone

(mudstone to wackestone to packstone with crinoids,

peloids?), in beds 5 cm thick containing rare chert

nodules. Thin section is skeletal packstone; bioclasts

are mainly crinoid ossicles and lesser foraminifers,

bryozoan fragments, spicules and algae(?). Matrix

contains 20 μm dolomite rhombs; silica partly

replaces some rhombs and bioclasts.

Heavy-mineral concentrate includes phosphatized

lithic fragments and minor talc-bearing metamorphic

rock fragments.

9.1 kg of rock was processed.

87

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°01'20"

162°46'25"

1 Sa element of Hindeodus sp. indet

CAI=~3 or 3.5

[98AKD13]

No older than early Early

Mississippian (middle

Kinderhookian) and no

younger than very earliest

Early Triassic.

Indeterminate (too few

conodonts).

Sample from Kogruk Formation overlying Kayak

Shale on Anxiety Ridge; sample from base of 50-ftthick Kogruk outcrop.

Medium-gray, fine- to medium-crystalline dolostone

with rare bioclasts and (or) peloids; 30% black chert.

Thin section is dolostone with sparse relict fossils,

including crinoid ossicles to 2 mm with silicified

centers. Dolomite crystals mostly subhedral, 300-

400 μm, with locally abundant intercrystalline

organic material.

7.7 kg of rock was processed.
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

93

KRA(?)

(?Amphitheatre

plate)

DeLong Mtns.

B-1

68°25'42"

162°15'50.4"

9 juvenile Pa elements Gnathodus cf. Gn. defectus

Dunn

2 Pa elements Rhachistognathus muricatus (Dunn)

29 bar, blade, and platform fragments

CAI=3.5-4

[04AD22A; 33783-PC]

late Late Mississippian (late

Chesterian; Rh. muricatus

Zone through Rh. primus

Zone).

Indeterminate (too few

conodonts); conodonts

present suggest

derivation from a

relatively shallowwater depositional

setting.

Upper Kogruk Formation(?); highest Lisburne Group

exposed. On trend with Lisburne at localities 94 and

116 (this table), but black shale and phosphate that

makes up the uppermost Lisburne at these localities

not seen here. Instead, contact zone consists of ~2 m

of Kogruk talus, overlain by 5 m of grass, overlain

by rubble of Etivluk Group (olive-brown to

greenish-gray mudstone overlain by green chert).

See text for further discussion of this sample.

Gray-weathering, dark-gray, mildly fetid, quite sooty

limestone. Sample from 15-cm-thick interval with 3-

to 5-cm-thick nodular beds. Skeletal mudstone to

wackestone(?), with abundant fossils on bedding

planes; bioclasts include brachiopods to 5 cm in

diameter, articulated crinoid columnals to 10 cm

long, and silicified rugose corals. Thin section is

skeletal supportstone that consists of large crinoid,

bryozoan, and brachiopod fragments in a finegrained matrix of peloids, small bioclasts (including

foraminifers), calcite cement, and scattered dolomite

rhombs. Some bioclasts partly silicified and (or)

dolomitized.

Heavy-mineral concentrate includes lesser phosphatic

carapace and brachiopod shell fragments.

6.0 kg of rock was processed.
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

94

KRA

(Amphitheatre

plate)

De Long Mtns.

B-1

68°23'39.5"/

162°27'21"

Barren

[03AD27B]

Upper Lisburne Group, ~2.5 m below top of unit.

Uppermost Lisburne is black shale capped by a layer

of phosphate pebbles to 14 cm in diameter. Basal

Siksikpuk Formation is orange-weathering, greenish

mudstone, with a thin zone of distinctly yelloworange-stained clay at the contact.

 Sample from top of 1-m-thick interval of light-grayweathering phosphatic limestone, in 10 to 30 cm

thick beds, underlain and overlain by several m of

carbonaceous black shale. Fresh surface of limestone

has "salt and pepper" look, with abundant black fineto coarse-sand-sized phosphate peloids and ooids, as

well as crinoid ossicles and brachiopods. Possible

cm-scale burrows; some filled with phosphate

pellets, others with chert. Thin section is

pelmatozoan-brachiopod-phosphatic clast

grainstone; some phosphatic clasts are ooids.

Heavy-mineral concentrate is mainly variably pyritic

black to dark-gray phosphatized spheroidal grains,

rare phosphatized pelmatozoan ossicles, and very

rare phosphatized gastropod steinkerns.

8.6 kg of rock was processed.

Loc. 15 (app. 1) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

94

KRA

(Amphitheatre

plate)

[cont.]

De Long Mtns.

B-1

68°23'39.5"/

162°27'21"

5 incomplete Pa elements Gnathodus texanus

Roundy

1 Sa element fragment Kladognathus sp. indet.

28 Pa elements Rhachistognathus prolixus

Baesemann and Lane

1 subadult incomplete Rhachistognathus sp. indet.

Unassigned elements:

 1 Pb and 3 M

140 indet. bar, blade, and platform fragments

1 conodont or bryozoan pearl

CAI=2.0-2.5

[03AD27F; 33758-PC]

middle Late Mississippian

(early Chesterian).

The co-occurrence of Gn.

texanus and Rh. prolixus,

restricts the age of the

collection to the early

Chesterian.

Indeterminate; too few

conodonts. The most

common conodonts in

the collection are

normal-marine species

that occur in platform

to deep-water

depositional settings.

Rh. prolixus is the

earliest

rhachistognathid;

younger species

typically occupied

high-energy,

relatively shallowwater depositional

regimes.

Upper Lisburne Group, ~5 m below top of unit.

 Sample from several-m-thick interval of limestone

with partings of black sooty shale. Beds thin (from

10 to 1 cm) and fine (limestone less grainy, shaly

partings increase) upward. Lower beds are darkgray, medium-gray-weathering skeletal

wackestone/packstone with crinoid ossicles and

productid brachiopods to 3 cm. Upper beds are

crinoid mudstone to wackestone that weathers

medium dark gray; beds wavy and irregular. Both

upper and lower beds included in sample. Thin

section is skeletal packstone/grainstone to mudstone

(mostly wacke/packstone) with dark, noncarbonate

mud matrix and minor dolomite and barite; bioclasts

mostly pelmatozoan fragments, lesser brachiopods,

and ostracodes.

Heavy-mineral concentrate consists mainly of

phosphatized rock fragments, dolomitized

pelmatozoan ossicles, lesser phosphatized gastropod

steinkerns, and scarce phosphatic brachiopod

fragments.

10 kg of rock was processed.

99

KRA

(Amphitheatre

plate)

De Long Mtns.

B-1

68°19'22"/

162°20'10"

1 gnathodid M element

Unassigned elements:

 3 juvenile Pa (2 morphotypes) and 1 Sa

38 indet. bar, blade, and platform fragments

CAI=2.5

[00AD10A; 33629-PC]

Mississippian. Indeterminate (too few

conodonts).

About 30 m above base of Kogruk Formation, which

here overlies the micritic limestone unit of Curtis

and others (1990); see table 8 for a sample from the

micritic limestone unit at this locality.

Light-gray- to medium-light-gray-weathering,

medium-dark-gray lime mudstone/wackestone with

~10% brown to black chert (probably replacing

bioclastic intervals); beds 10 to 30 cm thick. Thin

section is dolomitic calcareous spiculite with rare

crinoid ossicles.

Heavy-mineral concentrate includes fragments of

phosphatic chert and rare phosphatic brachiopod

fragments.

11.52 kg of rock was processed.

Loc. 14 (app. 1) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

110

KRA (Kelly

plate)

De Long Mtns.

A-1

68°14'01.7"/

162°05'10.8"

Kladognathus sp. indet.

 1 M and 2 Sb-Sc elements

1 unassigned Pb element

46 small indet. bar, blade, and platform fragments

CAI=2.0-2.5

[03AD29A; 33763-PC]

Mississippian; the only

generically identifiable

conodont in this collection

is Kladognathus, which

ranges from within the

Kinderhookian through

Chesterian.

Indeterminate (too few

generically

determinate

conodonts); the

relatively common,

small indeterminate

conodont fragments

indicate a postmortem

hydraulic winnow.

Sample ~10-15 m stratigraphically below top of

Kogruk Formation, which is here structurally

overlain by ultramafic rocks of the Misheguk

Mountain allochthon; contact probably a normal

fault.

Light- to medium-brownish-gray limestone, weathers

light to very light gray. Skeletal wackestone with

local colonial and solitary corals; 30-cm-thick

interval with 10- to 15-cm-thick beds. Thin section is

fractured and deformed crinoid grainstone with

bryozoans, brachiopods, and rare foraminifers.

6.4 kg of rock was processed.

Kladognathus sp.

 1 Sa and 1 Sb-Sc element fragments

5 S elements Synclydognathus geminus (Hinde)

Unassigned elements:

 2 Pa and 1 Sc

48 rather small indet. bar, blade, and platform

fragments

CAI=2.0-2.5

[03AD29B; 33761-PC]

late Early-middle Late

Mississippian (from within

the early Osagean-very

early Chesterian).

Indeterminate (too few

conodonts). Likely a

winnow; all

conodonts are small,

relatively thin element

fragments.

Sample ~2-3 m stratigraphically above 03AD29A.

Rubble crop (30-cm-thick beds) of medium-brownishgray limestone, weathers light gray. Skeletal

packstone with crinoid ossicles, silicified rugose

corals, and peloids(?). Thin section is partly

dolomitized crinoid supportstone with rare coral

fragments and patchy chert replacement.

6.4 kg of rock was processed.

111

KRA

De Long Mtns.

A-1

68°11'41.8"/

162°27'22"

10 deformed and sheared Pa element fragments

Bispathodus sp. indet. [either Bi. stabilis

(Branson and Mehl) or Bi. utahensis Sandberg

and Gutschick)]

39 indet. bar, blade, and platform fragments

CAI=3-3.5

[97AK23A]

late Late Devonian-middle

Late Mississippian (middle

Famennian-Meramecian).

Single-row bispathodid

biofacies; normalmarine, shallow- to

deep-water

depositional setting.

Sample from Kogruk Formation in fault contact below

Utukok Formation; see table 7 for Utukok sample

from this locality.

Medium-light-gray-weathering dolostone with rare

crinoid fragments and irregular dark-gray to black

chert nodules. Thin section is partly dolomitized

skeletal wackestone/packstone with dolomite rhombs

(40-200 μm) and <1% detrital quartz (and feldspar?)

silt and sand. Bioclasts mostly crenulated brachiopod

fragments (to 1 cm) and crinoid ossicles, with minor

calcispheres.

5.0 kg of rock was processed.
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

113

KRA

De Long Mtns.

A-1

68°12'00"/

162°26'12"

All conodonts are multiply fractured and all are

incomplete.

1 mid Pa element fragment Hindeodus sp. indet.

1 deformed and fractured incomplete Pa element

Cavusgnathus? sp. indet.

1 Pa posterior tip fragment Cavusgnathus sp. indet.

14 indet. bar, blade, and platform fragments

CAI=3-3.5

[97AK46A; 33394-PC]

middle-late Late

Mississippian (late

Meramecian-Chesterian).

Indeterminate (too few

generically

identifiable

conodonts).

Samples Kogruk Formation just above contact with

underlying Utukok Formation; see table 7 for

Utukok sample from this locality.

Light-gray-weathering, medium-gray limestone with

10 to 20% black irregular chert nodules. Thin section

is pervasively dolomitized limestone with abundant

calcite-filled fractures and veins. Dolomite ~80% or

more, in euhedral rhombs 20-200 μm in diameter. A

few remnant crinoid ossicles (to 1 mm diameter)

may still be calcite.

7.0 kg of rock was processed.

114

KRA

De Long Mtns.

A-1

68°12'0.6"/

162°25'12"

1 incomplete Pa element Cavusgnathus sp. indet.

1 juvenile Pa element Gnathodus homopunctatus

(Ziegler)? [pl. 2, fig. 13]

7 indet. bar, blade, and platform fragments

CAI=3-3.5

[97AK51A; 33395-PC]

Late Mississippian (late

Meramecian-early

Chesterian).

Indeterminate (too few

generically

identifiable

conodonts).

Sample taken at top of ~40-ft-thick outcrop of

limestone and chert overlying 5-ft-thick rubble zone

overlying outcrop of Kayak Shale(?). Thin section is

siliceous spiculite with rare radiolarians(?) and

subordinate dolomite rhombs (8-25 μm) cross-cut by

fractures and quartz veins.

7.9 kg of rock was processed.

5 Pa element fragments Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg

and Gutschick

1 unassigned Pb element

27 indet. bar, blade, and platform fragments

CAI=3

[97AK51C; 33401-PC]

 Mississippian (late

Kinderhookian-early

Chesterian).

Indeterminate (too few

generically

identifiable

conodonts).

Conodonts present

indicate postmortem

transport in a normalmarine environment.

Sample taken at base of~40-ft-thick outcrop of

limestone and chert just above 5-ft-thick rubble zone

overlying outcrop of Kayak Shale(?). Thin section is

calcareous spiculite with minor crinoid ossicles and

thin-shelled, spar-filled ostracodes, a lime mud

matrix and trace feldspar(?).

Heavy-mineral concentrate includes phosphatic

brachiopod fragments.

7.0 kg of rock was processed.
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

116

KRA (Kelly

plate)

Misheguk Mtn.

B-5

68°27'37.6"/

161°58'23.4"

1 Pa element fragment Gnathodus texanus Roundy

1 incomplete Pa element Hindeodus sp.

Idioprioniodus sp.

 1 Pb and 2 bar fragments

1 Sb-Sc element Kladognathus sp.

18 Pa elements (mostly juveniles)

Rhachistognathus prolixus Baesemann and Lane

Unassigned elements:

 6 Pb (3 morphotypes), 4 M, and 1 Sa

111 indet. bar, blade, and platform fragments

Conodonts are partly to considerably coated with

organic matter so that CAI is approximate but not

greater than 2.5.

[03AD38B; 33762-PC]

middle Late Mississippian

(early Chesterian).

This fauna correlates well

with that of 03AD27F (loc.

94, this table).

Indeterminate (too few

generically

determinate

conodonts). The

rhachistognathids

represent post-mortem

transport (a winnow)

from a shallow-water

setting; the relative

abundance of very

small indeterminate

bar, blade, and

platform fragments

reinforces the

interpretation of a

winnow.

Uppermost Lisburne Group. Sample from a 50-cmthick interval of limestone overlain by ~1 m of black

shale capped by ~5-10 cm of limy phosphatic rubble.

The phosphate is overlain by ~10 m of cover, and

then orange-weathering, olive-gray siliceous

mudstone of the Etivluk Group.

Dark-gray to dark-brownish-gray limestone, weathers

medium light gray, in 5- to 10-cm-thick beds;

crinoid-brachiopod wacke/packstone with bioclasts

(some silicified) to 2 cm long. Thin section is

brachiopod packstone with crinoid ossicles and

ostracodes, minor quartz silt and dolomite rhombs,

and rare phosphatic(?) clasts.

Heavy-mineral concentrate (nonmagnetic fraction) is

chiefly phosphatic and phosphatized mudstone to

siltstone fragments with minor phosphatic

brachiopod fragments and phosphatic tubes or tube

linings and rare composite glauconite-phosphaterhombohedral dolomite grains.

3.0 kg of rock was processed.

Loc. 17 (app. 1) of Dumoulin and others (2004).

121

EMA (Key

Creek plate)

Misheguk Mtn.

A-4

68°14'35"/

161°20'16"

All conodonts are small, mechanically broken

fragments. Although they have relatively low

thermal maturity, the conodonts have undergone

substantial brittle deformation.

1 Pa element fragment of a cavusgnathoid

2 juvenile incomplete Pa elements Gnathodus sp.

indet.

1 Pa element fragment Hindeodus sp. indet.

1 Sb-Sc element fragment Kladognathus sp. indet.

Synclydognathus sp. indet.

 2 M and (or) S element fragments

Unassigned elements:

 1 M and 1 Sa (fragments)

134 indet. bar, blade, and platform fragments

CAI=3

[00AD28A; 33639-PC]

early-middle Late

Mississippian

(Meramecian-early

Chesterian).

Indeterminate (too few

generically

determinate

conodonts). Species

association indicates a

probable inner to

middle shelf

depositional setting

Kogruk and Kuna Formations appear to interfinger in

this area. Sample from 8- to 10-m-high massive

outcrop of Kogruk.

Medium-gray to medium-dark-gray limestone,

weathers mottled light to medium light gray. Thinsection is partly dolomitized crinoidal supportstone

with abundant veins of sparry calcite.

Heavy-mineral concentrate includes phosphatized rock

fragments and lesser indeterminate phosphatized

bioclasts.

9.85 kg of rock was processed.

Loc. 11 (app. 1) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

147

Olistolith

derived from

EMA

(Wolverine

Creek plate)

De Long Mtns.

A-2

68°04'30"/

162°50'12.5"

6 Pa element fragments Hindeodus crassidentatus

(Branson and Mehl)?

26 indet. bar, blade, and platform fragments

CAI=2-2.5

[DDH 550 (Aqqaluk deposit), composite conodont

sample: 273.5-274.5, 277.5-278.5, 287-288 ft;

33619-PC]

 Early, but not earliest,

Mississippian (middle

Kinderhookian-Osagean).

Indeterminate (too few

identifiable

conodonts); conodonts

present indicate

postmortem transport

within or from a highenergy, relatively

shallow-water

depositional setting.

Kogruk Formation(?) near base of drill hole.

273.5-288.8 ft: Light- to medium-gray, bioclastic,

dolomitized, carbonate rock.

Thin-section data:

287 ft: Brecciated dolostone with relict bioclasts

(crinoid ossicles).

6.3 kg of rock was processed.

148

Olistolith

derived from

EMA

(Wolverine

Creek plate)

De Long Mtns.

A-2

68°04'28.6"/

162°50'04.3"

7 Pa elements (all incomplete) Bispathodus

utahensis Sandberg and Gutschick?

Hindeodus crassidentatus (Branson and Mehl)

 3 Pa (all incomplete) and 1 Pb elements

1 Sb-Sc element Kladognathus sp. indet.

Unassigned elements:

 1 M, 1 Sa, 1 Sb, and 7 Sc (3 morphotypes)

117 indet. bar, blade, and platform fragments

CAI=2

[DDH 605 (Main deposit), composite conodont

sample: 350-351, 354-355.5, 356-357, 357.5-

358.5, 359-360.3, 365.3-367 ft; 33620-PC]

Early, but not earliest,

Mississippian (late

Kinderhookian-Osagean).

Indeterminate (too few

identifiable

conodonts); conodonts

present indicate

postmortem transport

within or from a highenergy, relatively

shallow-water

depositional setting.

Kogruk Formation(?) (middle? part of unit).

350-367 ft: Calcareous dolostone to dolomitic

limestone; medium-gray to medium-light-gray,

variably brecciated.

Thin-section data:

350, 362.8 ft: Brecciated dolostone with relict bioclasts

(crinoid ossicles).

Heavy-mineral concentrate contains composite

dolomite-bearing phosphatized rock fragments and

indeterminate bioclasts.

9.54 kg of rock was processed.

159

EMA (Key

Creek plate;

Port Road

succession of

Dumoulin and

others, 2004)

Noatak D-3

67°51'04"/

163°15'25"

1 incomplete Pa element Bispathodus utahensis

Sandberg and Gutschick

1 incomplete Pa element Hindeodus sp. indet.

Kladognathus sp. indet.

 6 M and 5 Sb-Sc elements

1 unassigned ozarkodinid Pb element

1 Sc element Synclydognathus geminus (Hinde)

68 indet. bar, blade, and platform fragments

CAI=2.5

[DDH 1103, composite conodont Sample 1: 643.2-

43.8, 644-44.5, 645.5-46, 648.5-49, 658-58.5,

660-60.5, 662-62.5, 663-63.5, 667-67.3 ft;

33658-PC]

late Early-middle Late

Mississippian (Osageanearly Chesterian).

Indeterminate (too few

conodonts); conodonts

that are present all

indicate postmortem

transport within or

from a relatively highenergy, shallow-water

depositional

environment.

Lowest Kogruk Formation, just above gradational

contact with Utukok Formation at ~668 ft. See tables

7 and 11 for additional samples from this drill hole.

643.2-667.3 ft: White to light-gray, bioclastic

(crinoidal), dolomitized carbonate with 15-30%

light- to medium-gray chert nodules and interbeds as

much as 2.5 ft thick of green noncalcareous

mudstone (chert and mudstone not sampled for

conodonts).

Thin section data:

643.8 ft: Brecciated dolostone with patchy chert.

665 ft: Coarse crystalline dolostone with patchy chert,

relict crinoid ossicles to 4 mm in diameter, and rare

bryozoan fragments.

Heavy-mineral concentrate includes scarce coralline

fragments.

6.3 kg of rock was processed.

Loc. 8 (app. 1) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

160

EMA (Key

Creek plate;

Port Road

succession of

Dumoulin and

others, 2004)

Noatak D-3

67°52'40"/

163°11"00"

Bispathodus utahensis Sandberg and Gutschick

 71 Pa, 1 Pb, 3 M, 1 Sb and 1 Sc elements

1 P element fragment Embaysgnathus? sp.

Idioprioniodus spp. indet.

 2 Pa, 2 Pb, 5 M (mostly incomplete), and 4 S

elements

Kladognathus tenuis (Branson and Mehl)

 1 Pa-Pb, 19 M, 10 Sa, 38 Sb-Sc, and 23 bar

fragments (all conodonts are incomplete)

285 indet. bar, blade, and platform fragments

CAI=3

[DDH 1104, composite conodont sample 1: 678-80,

695-95.5, 699-701, 703-04, 709-10, 711-11.5 ft;

33662-PC]

latest Early-earliest Late

Mississippian (late

Osagean-early Meramecian;

Po. mehli-Lower Gn.

texanus Zone to Gn.

homopunctatus-Upper Gn.

texanus Zone, possibly Gn.

homopunctatus-Upper Gn.

texanus Zone).

Post-mortem transport

within or from a

bispathodidkladognathid

biofacies.

Taphonomy suggests

a relatively shallowwater depositional

setting.

Upper Kogruk Formation, here overlain by Ikalukrok

unit of Kuna Formation; contact (at 670 ft) could be

a fault.

678-711.5 ft: Very light to light-gray (outer), mediumlight to light-gray (inner), locally vuggy, locally

mottled dolostone with 15-20% medium-dark-gray

(outer), brownish-black (inner) chert in 1 cm to 1 ft

thick layers; bioclasts (crinoid ossicles, bryozoan?

fragments) especially notable in chert. About 20-

40% of dolostone is partly silicified, medium- to

medium-light-gray (outer). (Chert and partly

silicified dolostone not sampled for conodonts.)

Driller notes cave at 699-707.5 ft.

Thin section data:

680, 681 ft: Dolostone with relict crinoid ossicles and

local patchy to pervasive chert replacement.

709.2 ft: Dolostone (crystals mostly 300-400 μm) with

rare open vugs, some of which may be crinoid

ossicle molds.

709.4 ft: Like 709.2, but some vugs partly filled with

quartz and others contain dead oil.

Heavy-mineral concentrate is chiefly phosphatic

bioclasts (brachiopod fragments) and phosphatized

bioclasts and rock fragments.

7.1 kg of rock was processed.

Loc. 9 (app. 1) of Dumoulin and others (2004).
Table 6. Conodont samples from the Kogruk Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; AKD, K.D. Kelley; JS, J.M. Schmidt; KE, K. Evans; KS, K.W. Sherwood; MD, C.F. Mayfield; and TR, I.L. Tailleur. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for

dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc.,

locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

160

EMA (Key

Creek plate;

Port Road

succession of

Dumoulin and

others, 2004)

[cont.]

Noatak D-3

67°52'40"/

163°11"00"

Abundant conodonts; none are complete, a minor

number are identifiable to genus and (or) species,

and most are relatively small indeterminate

fragments.

32 incomplete to nearly complete Pa elements

Bispathodus utahensis Sandberg and Gutschick

Idioprioniodus cf. I. healdi (Roundy)

 7 Pb?, 4 M, 5 Sc elements

Kladognathus sp. indet.

 1 Pa-Pb, 12 M, 1 Sa, and 35 Sb-Sc elements (all

fragments)

Unassigned elements:

 4 Pb and 1 M

655 indet. bar, blade, and platform fragments

CAI=3

[DDH 1104, composite conodont sample 2: 713.5-

14, 714-720 ft (only 2 ft of section recovered in

this 6-ft-interval; 1.5 ft section was sampled);

33663-PC]

latest Early-early Late

Mississippian (late

Osagean-Meramecian).

The overlying collection

restricts the upper age limit

of this sample to the Gn.

homopunctatus-Upper Gn.

texanus Zone (early

Meramecian).

Post-mortem transport

from or within a

bispathodidkladognathid

biofacies. Breakage

indicates transport

within or from a highenergy depositional

setting.

Kogruk Formation, upper part, immediately below

DDH 1104 composite conodont sample 1.

713.5-720 ft: Dolostone (locally cherty) as described

above.

Heavy-mineral concentrate is chiefly partly pyritic to

nonpyritic phosphatic and phosphatized bioclasts

(including phosphatic brachiopod fragments).

2.4 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

9

KRA (Kelly

plate)

De Long Mtns.

A-3

68°11'44.6"/

163°41'54.4"

3 Pa elements Eotaphrus burlingtonensis Pierce

and Langenheim?

10 M elements Gnathodus sp. indet.

Hindeodus crassidentatus (Branson and Mehl)

 15 Pa, 4 Pb, 1 M, 2 Sa, 14 Sb, and 8 Sc elements

Idioprioniodus sp. indet.

 1 Pb, 2 M, and 2 Sc elements

Kladognathus sp.

 24 M, 12 Sa, and 36 Sb-Sc elements

2 Pa elements Polygnathus communis Branson and

Mehl

Synclydognathus geminus (Hinde)

 34 Pa, 3 Pb, and 19 M and S elements

Unassigned elements;

 12 Pa (3 morphotypes; all fragments), 6 Pb (4

morphotypes), 10 M (3 morphotypes), 7 Sc (3

morphotypes)

274 indet. bar, blade, and platform fragments

CAI=2

[00AD5A; 33626-PC]

late Early Mississippian

(middle-late Osagean; Sc.

anchoralis-D. latus ZonePo. mehli-Lower Gn.

texanus Zone).

Mixed biofacies;

postmortem transport

from a range of

shallow-water

depositional

environments.

Within lower part of Utukok Formation (base is a

fault).

Light-gray-weathering, medium-gray, irregularly

bedded skeletal supportstone with variable amounts

of quartz; beds 3 to 20 cm thick. Thin section is a

diverse skeletal grainstone with ~25% noncarbonate

detrital grains (mainly quartz); bioclasts include

brachiopods, crinoids, ostracodes, and foraminifers.

Heavy-mineral concentrate includes scarce

phosphatized bryozoan fragments, rare ichthyoliths,

and phosphatized foraminiferan steinkerns.

9.6 kg of rock was processed.

18

Olistolith

De Long Mtns.

A-3

68°08'24"/

163°25'48"

1 Pa element Bispathodus plumulus nodosus

(Rhodes, Austin, and Druce)

9 Pa element anterior platform fragments

Siphonodella sp. indet. of middle-late

Kinderhookian morphotype

15 indet. blade and platform fragments (most

probably small siphonodellid fragments)

CAI=2.5-3

[79TR144; 27596-PC]

early Early Mississippian

(middle-late

Kinderhookian).

Siphonodellid biofacies;

postmortem transport

within or from a

middle shelf or

deeper, relatively

quiet water

depositional setting.

This collection resembles faunules from the Rough

Mountain unit of the Lisburne Group (Dumoulin and

Harris, 1997).

Fossil loc. 21, Mayfield and others (1990).
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

25

Olistolith,

probably

derived from

PCA or KRA

De Long Mtns.

A-3

68°06'06"/

163°34'18"

3 Pa elements (all incomplete) Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg

and Gutschick

17 Pa elements Bispathodus plumulus nodosus

(Rhodes, Austin, and Druce)

10 Pa elements Hindeodus crassidentatus (Hinde)

4 Sc elements Kladognathus sp. indet.

7 Pa elements Polygnathus bischoffi Rhodes,

Austin and Druce [pl. 2, figs. 20, 21]

15 Pa elements Polygnathus communis communis

Branson and Mehl and Po. c. carina Hass

1 Pa element (incomplete) Polygnathus vogesi

1 large Pa fragment Polygnathus sp. indet.

2 Pa elements Pseudopolygnathus marginatus

(Branson and Mehl)? [pl. 2, figs. 23, 24]

1 Pa element Pseudopolygnathus multistriatus

Mehl and Thomas [pl. 2, figs. 25, 26]

13 Pa elements (most incomplete but very large)

Pseudopolygnathus n. sp.? of Dumoulin and

Harris (1997, fig. 9H) from the Anuik River

sequence of the Endicott Mtns. allochthon

Siphonodella spp.

 14 Pa (mostly fragments and juveniles), 1 Pb, and

1 M elements

1 Sb element Synclydognathus geminus (Hinde)

[pl. 2, fig. 22]

Unassigned elements:

 9 Pb (+5 morphotypes), 11 M (+5 morphotypes),

5 Sa (2 morphotypes), 2 Sb (2 morphotypes), and

4 Sc (3 morphotypes)

52 indet. bar, blade, and platform fragments

CAI=3

[79EK175C; 27553-PC]

early Early Mississippian

(middle-late

Kinderhookian).

Mixed biofacies;

postmortem transport

in a shelf depositional

setting. Most of the

conodonts (with the

exception of the

siphonodellids)

suggest a relatively

high-energy, shallowwater setting.

Bedded limestone underlying interbedded limestone

and chert.

This fauna resembles that of the Rough Mountain

Creek unit of the Lisburne Group (Dumoulin and

Harris 1997; Mull and others, 1997).

Fossil loc. 24, Mayfield and others (1990).
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

31

EMA (Key

Creek plate)

De Long Mtns.

A-3

68°02'21.8"/

163°12'03.6"

2 incomplete Pa elements Polygnathus bischoffi

Rhodes, Austin, and Druce

8 Pa element fragments Polygnathus communis

communis Branson and Mehl

1 juvenile Pa element Polygnathus flabellus

Branson and Mehl?

9 Pa element fragments Polygnathus sp. indet. and

(or) Pseudopolygnathus sp. indet.

1 Pa element Pseudopolygnathus sp. [pl. 2, fig. 17]

2 juvenile Pa elements Pseudopolygnathus? sp.

indet.

6 Pa element fragments Pseudopolygnathus spp.

indet.

Synclydognathus geminus (Hinde)

 1 Pb and 1 S elements

Unassigned elements:

 3 Pb (2 morphotypes), 1 M, 3 Sa (2

morphotypes), and 1 Sc

137 indet. bar, blade, and platform fragments

CAI=3.5

[00AD6A; 33627-PC]

late Early Mississippian

(middle-middle late

Osagean).

Postmortem transport

within or from a

pseudopolygnathidpolygnathid biofacies;

platform or shelf

depositional setting.

Lower part of Utukok Formation.

Orange-gray- to medium-light-gray-weathering,

medium-gray, partly bioturbated supportstone with

pelmatozoans in beds 8 to 15 cm thick. Thin section

is diverse skeletal supportstone with trace quartz silt;

bioclasts include brachiopods, crinoids, ostracodes,

foraminifers, gastropods, and algae(?).

Heavy-mineral concentrate includes micaceous,

quartzose metamorphic(?) rock fragments, white

mica flakes, and rare phosphatized bryozoan and

pelmatozoan fragments and ostracodes.

9.9 kg of rock was processed.

Loc. 17 (fig. 2) of Dumoulin and others (2004).

40

KRA (Wulik

Peaks plate)

De Long Mtns.

B-2

68°16'20.3"/

163°11'10.7"

1 unassigned Pb element

8 indet. bar and blade fragments

CAI=2.5-3

[KE98-14E; 33501-PC]

Mississippian Indeterminate (too few

conodonts).

Middle Utukok Formation. See table 6 for Kogruk

Formation samples from this location.

Thin section is fine-grained skeletal-peloidal

grainstone; bioclasts chiefly calcispheres and

foraminifers with a few outsized crinoid ossicles.

Heavy-mineral concentrate includes barite(?) grains,

minor phosphatized spines, and phosphatic

brachiopod fragments.

2.9 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

51 De Long Mtns.

A-2

68°12'42"/

163°10'42"

9 indet. small bar and blade fragments

CAI=3

[KS98-85; 33606-PC]

Ordovician-Triassic on the

basis of conodonts;

Mississippian on the basis

of stratigraphic unit.

Indeterminate (too few

conodonts).

Lower Utukok Formation.

Carbonate tempestites, 10 to 40 cm thick (40%),

interbedded with gray calcareous shale. Thin section

is calcite>quartz siltstone with locally abundant

calcareous spicules, lesser calcispheres, algae, and

outsized crinoid and bryozoan fragments. Noncarbonate detritus 5-30%; chiefly quartz but includes

plagioclase feldspar.

Heavy-mineral concentrate contains scarce phosphatic

shell fragments.

5.1 kg of rock was processed.

52

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°12'24"/

163°11'48"

Bispathodus utahensis Sandberg and Gutschick

 52 Pa and 1 M elements [pl. 3, fig. 2]

Kladognathus tenuis (Branson and Mehl)

 3 Pa-Pb element fragments, 5 M, 2 Sa, and 15 SbSc elements

1 juvenile Pa element Pseudopolygnathus sp. [pl. 3,

fig. 1]

1 Sa element Synclydognathus sp.

5 Pa elements Vogelgnathus cf. V. pesaquidi

Purnell and von Bitter

Unassigned digyrate apparatus:

 1 P and 2 Sb-Sc elements

Unassigned elements:

 6 M (3 morphotypes), 4 Sa (3 morphotypes), 3 Sb

(3 morphotypes), and 13 Sc (5 morphotypes)

232 indet. bar, blade, and platform fragments

CAI=2.5-3

[97AK107A; 33400-PC]

late Early Mississippian

(middle-late Osagean); the

occurrence of a

pseudopolygnathid with

Vogelgnathus cf. V.

pesaquidi restricts the age

of the collection to the

middle or late Osagean.

According to Purnell and

von Bitter (1992), V.

pesaquidi and any

vogelgnathids like it do not

appear below the middle

Osagean, and

Pseudopolygnathus does

not range above the

Osagean.

Bispathodid biofacies;

this is a eurytopic

species that is most

common in shallowand deep-water

environments. The

associated conodonts

suggest a shallowwater depositional

setting.

Top of Utukok Formation.

Medium-light to medium-gray-weathering, mediumdark-gray to medium-brown-gray, coarse to very

coarse grained limestone. Beds 10- to 40-cm-thick

with dark-gray argillaceous partings, some crosslaminae, and local chert nodules. Thin section is very

poorly sorted skeletal packstone; bioclasts (to 7 mm)

include crinoid ossicles (50%), brachiopods,

bryozoans, ostracodes, and a few foraminifers. Some

shelter porosity; fair amount of diagenetic alteration,

including silica replacement of bioclasts (and

locally, matrix) and dolomite replacement of mud

matrix (mostly rhombohedral dolomite rhombs <60

μm in diameter).

Heavy-mineral concentrate is chiefly phosphatic and

phosphatized bioclasts including ichthyoliths,

bryozoans, and brachiopods.

14.1 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

53

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°12'17"/

163°08'39"

Bispathodus stabilis (Branson and Mehl) or Bi.

utahensis Sandberg and Gutschick

 3 incomplete Pa and 1 Pb elements

Synclydognathus sp. indet.

 6 Pa (fragments) and 1 S or M (small fragment)

elements

digyrate apparatus

 1 Pa-Pb and 3 Sb-Sc element fragments

 2 unassigned M elements (2 morphotypes)

 1 unassigned Sa or Sb element fragment

38 indet. bar, blade, and platform fragments

CAI=3

[97AK96A; 33397-PC]

Early, but not earliest

Mississippian (middle

Kinderhookian-Osagean).

Indeterminate (too few

generically

determinate

conodonts).

Top of 250-ft-thick interval within Utukok Formation

that resembles Kogruk Formation in lithofacies.

Medium-light-gray-weathering, medium- to mediumdark-gray limestone in 5- to 50-cm-thick beds. Thin

section is loosely packed, coarse skeletal grainstone;

bioclasts dominantly crinoid ossicles and algae, also

brachiopods, foraminifers, ostracodes, and

echinoderm spines. Skeletal pores filled with calcite

spar. Trace dolomite (20 μm rhombs) replacing

minor amounts of calcite mud(?).

7.1 kg of rock was processed.

Hindeodus crassidentatus (Branson and Mehl)

 8 Pa, 3 Pb, 9 M, 1 Sa, and 2 Sc elements

Kladognathus sp.

 3 Sa and 11 Sb-Sc elements

Unassigned elements:

 4 Pb (3 morphotypes) and 2 Sc

28 indet. bar, blade, and platform fragments

CAI=3

[97AK96B; 33398-PC]

Early, but not earliest

Mississippian (middle

Kinderhookian-Osagean,

possibly late Osagean).

Hindeodid biofacies;

relatively shallow

water, normal-marine

to near restricted

depositional setting.

Base of 250-ft-thick interval within Utukok Formation

that resembles Kogruk Formation in lithofacies.

Limestone similar to 97AK96A. Thin section is

skeletal grainstone like 97AK96A but more closely

packed, better sorted, finer grained (bioclasts mostly

fine grained, some to 2 mm). Grains include crinoid

ossicles, foraminifers, algae, brachiopods, and

ostracodes; 10% of bioclasts micritized. Some

skeletal pores filled with micrite, some with calcite

spar. Minor (<1%) detrital monocrystalline quartz

silt to very fine sand.

Heavy-mineral concentrate is chiefly phosphatized

bioclasts (mainly pelmatozoan fragments and

slightly curved irregular tubes).

7.2 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

53

KRA (Wulik

Peaks plate)

[cont.]

De Long Mtns.

A-2

68°12'17"/

163°08'39"

5 Pa element fragments Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg

and Gutschick

1 Pa element fragment Polygnathus sp. indet.

1 Sa element Hindeodus sp. indet.

Unassigned elements:

 2 M, 3 Sa, 1 Sb, and 3 Sc elements

20 indet. bar, blade, and platform fragments

CAI=~3

[97AK96C; 33399-PC]

Early but not earliest

Mississippian (middle

Kinderhookian-Osagean)

Indeterminate (too few

conodonts); conodonts

present indicate a

normal-marine, shelf

or platform

depositional setting.

Utukok Formation, ~80 ft above 97AK96A.

Yellow-gray to pale yellow-brown-weathering, darkgray, impure limestone with abundant corals and

brachiopods and local Zoophycus traces. Beds 1 to

10 cm thick. Thin section is skeletal grainstone

similar to 97AK96A, with a poorly sorted mix of

bigger crinoid ossicles and smaller algae; traces of

quartz silt and minor dolomite rhombs.

Heavy-mineral concentrate includes fluorite,

phosphatic brachiopod fragments, and ichthyoliths.

17.0 kg of rock was processed.

54

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°12'18.2"/

163°08'10"

Barren

[97AK99A]

Lower part of Utukok Formation (~160 ft above base).

Thin section is muddy quartz siltstone with

noncalcareous mud and calcite cement. Clasts

mostly monocrystalline quartz, lesser crinoid

ossicles (to 400 μm), white mica, and rare chert(?).

7.0 kg of rock was processed.

55

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°11'49"/

163°10'19"

4 indet. bar and blade fragments

CAI=4

[98JS10A; 33613-PC]

Ordovician-Permian; unit is

known to be Mississippian.

Indeterminate (too few

conodonts).

Near base of Utukok Formation.

Orange-weathering muddy limestone with

brachiopods, hummocky cross-beds, and 30%

calcareous shale interbeds. Thin section is coarsegrained crinoidal packstone with minor quartz silt.

Heavy-mineral concentrate includes phosphatized

composite grains, lesser phosphatic brachiopod

fragments, and rare ichthyoliths.

5.7 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

56

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°11'34.5"/

163°10'0.8"

Barren

[KE98-10C]

Lower part of middle unit of Utukok Formation. See

table 6 for Kogruk Formation sample from this

locality.

Medium-light-gray- to light-brown-gray-weathering,

medium-dark-gray, very fine grained limestone.

Thin section is fine-grained skeletal grainstone with

~5% detrital quartz and notable calcareous sponge

spicules and calcispheres.

Heavy-mineral concentrate includes spines and rare

silicified ostracodes with pyrite.

4.4 kg of rock was processed.

57 De Long Mtns.

A-2

68°11'24"/

163°09'03.6"

Kladognathus sp.

 2 M and 3 Sb-Sc elements

1 Sb element Synclydognathus geminus (Hinde)

Unassigned elements:

 1 Sb and 1 Sc

30 indet. bar, blade, and platform fragments

CAI=3

[98JS-8A; 33610-PC]

late Early to middle late Late

Mississippian (Osageanearly Chesterian);

associated coral indicates

Late Mississippian (see

Remarks).

Indeterminate (too few

conodonts). The

preservation of the

conodonts suggests

significant

postmortem transport.

Transitional contact between Utukok Formation and

overlying Kogruk Formation.

Light-orange-brown-weathering, locally fossiliferous

limestone with corals, brachiopods, and crinoids,

interbedded with light-gray lime grainstone with rare

chert. Thin section is skeletal packstone with

algae(?), pelmatozoan fragments (some partly

silicified), and possible dissolved ooids replaced by

calcite spar.

Heavy-mineral concentrate includes ichthyoliths, lesser

phosphatic brachiopod fragments, phosphatized

bioclasts (mainly crinoid ossicles and tube

steinkerns), and fluorite.

6.0 kg of rock was processed.

Lithostrotion (Siphonodendron) sp. of Late

Mississippian (Meramecian-Chesterian) age occurs

in these strata (R.B. Blodgett, Oregon State

University, unpublished fossil report, 1999).

62

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°10'51"/

163°10'25.6"

Hindeodus cristulus (Youngquist and Miller)

 2 Pa, 1 Pb, 1 M, 1 Sa-Sb, and 1 Sc elements

5 Sb-Sc elements Kladognathus sp.

Unassigned elements:

 1 Pb and 1 Sc

28 indet. bar, blade, and platform fragments

CAI=3

[98JS7H; 33608-PC]

latest Early-early Late

Mississippian (late

Osagean-Meramecian).

Indeterminate (too few

generically

identifiable

conodonts); conodonts

present indicate postmortem transport

within or from a

relatively highenergy, near restricted

depositional setting.

See tables 6 and 9 for additional samples from this

locality.

Sample from mound-shaped bodies, ~1-1.5 m high,

made of crinoid grainstone and local algae(?). Thin

section is fine-grained, skeletal peloidal grainstone

with foraminifers and micritized bioclasts including

outsized bryozoan and pelmatozoan fragments.

Heavy-mineral concentrate is chiefly fluorite and

phosphatized and dolomitized carbonate grains and

bioclasts (mainly pelmatozoan ossicles).

7.32 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

63

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°08'45.6"/

163°05'42.6"

Hindeodus crassidentatus (Branson and Mehl)

 6 Pa, 3 Pb, 2 M, 1 Sa, 2 Sb and 1 Sc elements [pl.

2, fig. 27]

Kladognathus sp.

 5 M and 19 Sb-Sc (all incomplete) elements

Synclydognathus geminus (Hinde)

 4 Pa, 1 M, 1 Sa, 1 Sb1, 5 Sc, and 3 indet. S

elements

1 Sb and 1 Sc unassigned elements

142 small indet. bar, blade, and platform fragments

CAI=3.5

[KE98-22; 33506-PC]

late Early Mississippian

(Osagean).

Postmortem transport

within the hindeodidsynclydognathid

biofacies; species

association suggests

relatively shallowwater, near and (or)

intermittently

restricted depositional

setting.

Sample from lens-shaped outcrops of limestone and

shale. Thin section is packed crinoid-bryozoan

grainstone with thin layers of packstone; other

bioclasts include ostracode valves, calcareous

spicules, and possible brachiopod fragments.

Heavy-mineral concentrate is chiefly coarsely

phosphatized and dolomitized mostly indeterminate

bioclasts (spines and (or) spicules), minor scarce

phosphatic brachiopod fragments, and ichthyoliths.

6.4 kg of rock was processed.

Loc. 13 (fig. 2) of Dumoulin and others (2004).

64

EMA

(Wolverine

Creek plate;

Rok window)

DeLong Mtns.

A-2

68°08'51"/

163°05'13.8"

Hindeodus crassidentatus (Branson and Mehl)

 3 Pa and 1 M elements [pl. 2, fig. 28]

Kladognathus sp. indet.

 1 Sa and 2 Sb-Sc elements

Synclydognathus geminus (Hinde)

 2 Pa and 4 S and M elements [pl. 2, fig. 29]

1 unassigned M element

11 indet. bar, blade, and platform fragments

CAI=3-4 (much organic matter, so CAI cannot be

precisely fixed).

[79CX119A; 33348-PC]

late Early Mississippian

(Osagean).

Postmortem transport

within or from a

shallow-water,

relatively high-energy

depositional setting;

mixed biofacies.

Limestone; stratigraphic position within the Utukok

Formation unknown.

2.7 kg of rock was processed.

Fossil loc. 11, Ellersieck and others (1990).

Hindeodus crassidentatus (Branson and Mehl)

 1 Pa, 4 M, and 1 Sc elements

Kladognathus sp. indet.

 2 Sa and 2 Sb-Sc elements

Synclydognathus geminus (Hinde)

12 Pa, 4 Pb, and 4 S and M elements

2 unassigned Sc elements

55 indet. bar, blade, and platform fragments

6 ichthyoliths

CAI=4

[8-16-83F; 29232-PC]

late Early Mississippian

(Osagean).

Synclydognathidhindeodid biofacies;

relatively shallowwater and possibly

near-restricted

depositional setting.

Sample near base of Utukok Formation.

Medium-dark-gray, fine- to medium-grained, crinoidbearing packstone containing chert and black shale

(60-70% limestone and 40-30% shale and chert).

Thin section is packed skeletal packstone made up of

ferroan and nonferroan calcite with irregular masses

of ferroan dolomite (crystals <100 μm). Bioclasts

mostly (60-80%) pelmatozoan fragments (to 3 mm),

also bryozoan, coral, red algae(?), and trilobite(?)

fragments. Matrix of brown mud and chert with

abundant tiny calcareous spicules.

5.4 kg of rock was processed.

Sample collected by A.G. Harris.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

70

KRA (Kelly

plate)

De Long Mtns.

A-2

68°09'13.6"/

162°37'31"

1 incomplete Pa element Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg

and Gutschick

Kladognathus sp.

 1 M, 2 Sa, and 5 Sb-Sc elements (all incomplete)

1 incomplete Pa element Polygnathus communis

Branson and Mehl

Synclydognathus libratus (Varker)

 1 Pa, 1 Pb, and 12 S and M elements (all

incomplete)

1 Sa and 1 Sc unassigned elements

80 indet. bar, blade, and platform fragments

(mostly small)

CAI=3.5

[00AD1B; 33623-PC]

late Early Mississippian

(Osagean).

Postmortem transport

within or from a

relatively highenergy, shallow-water

environment.

Within lower part of Utukok Formation; base of

Utukok is a fault.

Light-gray- to medium-light-gray-weathering, light- to

medium-light-gray, thick- to medium-bedded partly

muddy and bioturbated supportstone with abundant

to common pelmatozoan ossicles. Thin section is

skeletal grainstone with pelmatozoan debris,

foraminifers, and algae, plus a few percent detrital

quartz and plagioclase feldspar. Some bioclasts have

micritic rims.

Heavy-mineral concentrate includes phosphatized rock

fragments and bioclasts (chiefly pelmatozoan

ossicles, and foraminiferan and bryozoan fragments)

and minor fluorite.

10.9 kg of rock was processed.

73

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°07'00"/

163°08'36"

Kladognathus sp.

 3 M, 2 Sa, and 3 Sb-Sc elements

Synclydognathus geminus (Hinde)

 2 Pa, 2 Pb, and 1 S elements

Unassigned elements:

 2 Pb, 1 M, and 3 Sc (3 morphotypes)

20 indet. bar, blade, and platform fragments

CAI=3

[KE98-25C; 33605-PC]

late Early Mississippian

(Osagean).

Indeterminate (too few

generically

identifiable

conodonts);

postmortem transport

within a shallowwater depositional

setting.

Upper Utukok Formation. See table 6 for Kogruk

Formation samples from this location.

Light-gray-weathering, medium-dark-gray, very fine

grained limestone with rare coarse crinoid ossicles.

Thin section is crinoid-bryozoan packstone with a

dolomitized micritic matrix; other bioclasts are

brachiopods, ostracodes, calcareous and siliceous

spicules, and calcispheres.

Heavy-mineral concentrate contains ichthyoliths.

4.2 kg of rock was processed.

Loc. 14 (fig. 2) of Dumoulin and others (2004).

74

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°06'56.8"/

163°07'20.8"

14 indet. small bar and blade fragments

5 ichthyoliths

CAI=3.5-4

[00AD3A; 33624-PC]

Mississippian on the basis of

stratigraphic position and

stratigraphic unit.

Indeterminate (no

generically

identifiable

conodonts). Probably

a postmortem

winnow.

Base of Utukok Formation or interbedded Utukok

Formation and Kayak Formation.

Grayish-red- to light-orange-weathering, mediumdark-gray, fetid crinoidal supportstone with up to

50% chert and locally abundant brachiopods; beds

undulatory and 3 to 7 cm thick. Thin section is

crinoidal grainstone with lesser bryozoan and

brachiopod fragments, a few clay lenses

(intraclasts?), and traces of very fine quartz sand.

Heavy-mineral concentrate includes minor dolomitized

bryozoan fragments, indeterminate bioclasts, and

scarce phosphatic brachiopod fragments.

8.0 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

79 De Long Mtns.

A-2

68°01'31.7"/

163°03'0.6"

Barren

[KS98-83]

Utukok Formation(?)

Argillaceous or siliceous limestone and calcareous

siltstone. Thin section is fine-grained dolostone.

5.1 kg of rock was processed.

80 De Long Mtns.

A-2

68°01'27.8"/

163°03'13"

Barren

[KS98-82]

Utukok Formation(?)

Moderate-yellow-brown-weathering, medium-darkgray, very fine grained limestone. Thin section is

micrite with scattered, abundant, very fine dolomite

euhedra.

6.52 kg of rock was processed.

81

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°01'19.2"/

163°03'07.2"

Barren

[98JS5B]

Turbidites(?) in lower part of Utukok Formation.

Dark-gray-weathering, dark-gray limestone

(calcarenite) with 5% black shale partings. Thin

section is deformed calcisiltite with dark (muddy?)

seams and minor skeletal(?) fragments.

4.6 kg of rock was processed.

83

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°00'57.5"/

162°59'33"

Kladognathus sp. indet. (chiefly fragments)

 1 M, 1 Sa, 3 Sb-Sc, and 8 small bar fragments

5 ichthyoliths

CAI=2 or 3 (conodonts covered with mineral and

organic matter).

[98AD14G; 33419-PC]

Mississippian but not very

earliest Mississippian

(middle KinderhookianChesterian)

Indeterminate (too few

conodonts).

Conodonts present

suggest shallow-water

depositional setting.

Utukok Formation; stratigraphically underlies Kogruk

Formation sampled as 98AD15A (loc. 84, table 6).

Dark-yellow-orange skeletal supportstone (with

bryozoans, crinoids, corals, brachiopods) in irregular

nodular beds as much as 10 cm thick, interbedded

with thinner bedded sandy limestone; sample is from

middle of 20-m-thick section. Thin section is skeletal

wackestone to packstone, made up of large crinoid

ossicles (to 7 mm) and smaller bryozoan and

ostracode? fragments in a matrix of dolomite

rhombs, brown noncalcareous mud, and local calcite

cement.

Heavy-mineral concentrate includes phosphatized rock

fragments and phosphatized bioclasts (chiefly

phosphatic brachiopods and ichthyoliths).

5.7 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

102

KRA (Kelly

plate)

De Long Mtns.

B-1

68°20'33.8"/

162°12'47"

1 Pa Gnathodus cuneiformis Mehl and Thomas [pl.

2, fig. 16]

1 Pa element fragment Hindeodus sp. indet., or

Synclydognathus sp. indet.

1 Pa element fragment Polygnathus sp. indet. or

Pseudopolygnathus sp. indet.

Unassigned elements:

 2 M, 1 Sb, and 1 Sc

17 indet. bar, blade, and platform fragments

CAI=2.5

[00AD15A; 33630-PC]

late Early Mississippian

(lower half of the Osagean;

Lower Gn. typicus

Subzone-Sc. anchoralis-Do.

latus Zone).

Indeterminate (too few

conodonts); conodonts

present indicate

normal-marine

depositional setting.

Five slabs of quartzose limestone and calcareous

sandstone collected from talus train derived from

outcrop source a few hundred meters up valley.

Samples are planar- to crudely-bedded, parallel- and

cross-bedded, grayish-orange- and medium-lightgray-weathering, medium-gray, quartzose

calcarenite to calcareous sandstone containing

abundant brachiopods (mostly spiriferids) and minor

pelmatozoan ossicles. Strata separated by about 75 to

100 ft of dark shale from underlying Devonian

carbonate rocks. Thin-section is skeletal grainstone

with 10-20% ooids and 5-30% noncarbonate sand

(mainly quartz, some plagioclase feldspar). Bioclasts

chiefly crinoid ossicles, lesser foraminifers and

brachiopod fragments; some bioclasts micritized.

Heavy-mineral concentrate includes pyritic, silicified,

phosphatic brachiopod fragments, and ichthyoliths.

10.25 kg of rock was processed.

Loc. 16 (app. 1) of Dumoulin and others (2004).

108

KRA

De Long Mtns.

A-1

68°14'54"/

162°14'30"

1 mid Pa element fragment Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg

and Gutschick

2 Pa elements Polygnathus communis Branson and

Mehl

1 unassigned M element

CAI=3-3.5

[97AK65C]

very late Late Devonian-Early

Mississippian (late

Famennian-latest Osagean).

Indeterminate. Sandstone at base of Utukok Formation, overlying

Devonian carbonate rocks (see table 12 for samples

from these rocks).

Yellow-gray-weathering, light-medium-gray, finegrained, well-sorted calcareous quartz sandstone

with brachiopod(?) molds. Thin section is fairly well

sorted, very fine grained quartz sandstone with

patchy (trace-15%) calcite cement (and grains?) and

minor dolomite. Clasts are 75% monocrystalline

quartz and 5-10% chert, with trace polycrystalline

quartz, metamorphic lithic clasts, and crinoid

ossicles (to 1.5 mm).

Heavy-mineral concentrate includes phosphatized

bioclasts.

7.3 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

108

KRA

[cont.]

De Long Mtns.

A-1

68°14'54"/

162°14'30"

1 Pa element fragment Polygnathus sp. indet.

Synclydognathus sp. indet.

 1 Pa (fragment) and 2 S elements

 3 digyrate element fragments (1 Pa-Pb and 2 Sc)

81 indet. bar, blade, and platform fragments

CAI=3.5

[97AK66; 33396-PC]

probably late Early

Mississippian (middle

Kinderhookian-Osagean,

probably Osagean).

Indeterminate (too few

conodonts). Large

number of conodont

fragments indicates

proximity to a highenergy environment.

Utukok Formation, ~70 feet above basal sandstone

(97AK65C).

Thin section is diverse skeletal grainstone with locally

abundant silt to very fine sand that is mostly

monocrystalline quartz, rare polycrystalline quartz

and feldspar(?). Main bioclast is bladed algae(?) (2-4

mm by 0.5-0.75 mm); blades were probably

originally aragonite, now calcite spar with micritic

rims. Other clasts include ostracodes, crinoids,

bryozoans, various small algae(?), and trace

ooids(?).

Heavy-mineral concentrate includes phosphatized and

pyritized bioclasts (ostracodes and phosphatic

brachiopod fragments).

6.3 kg of rock was processed.

111

KRA

De Long Mtns.

A-1

68°11'41.8"/

162°27'22"

Barren

[97AK23B]

Utukok Formation in fault contact above Kogruk

Formation; see table 6 for Kogruk sample from this

locality.

Light-brown- to dark-yellow-orange-weathering,

medium-gray to light-brownish gray recrystallized

limestone that contains brachiopods and parallel- and

cross-laminae. Thin section is tectonized and

deformed, very fine grained sandstone with rare

bioclasts. Abundant seams, fractures, and veins.

Sandstone grains mostly monocrystalline quartz;

many grains contain fractures filled with white mica.

Tiny flecks of white mica throughout slide. A few

possible crinoid ossicles; most calcite is sparry +

anhedral.

6.5 kg of rock was processed.

113

KRA

De Long Mtns.

A-1

68°12'00"/

162°26'12"

Barren

[97AK46B]

Utukok Formation, 15 feet below contact with

overlying Kogruk Formation; see table 6 for Kogruk

sample from this locality.

Gray-brown- and yellow-gray-weathering, lightmedium-gray, fossiliferous sandy limestone. Thin

section is very fine grained quartz sandstone with

silica cement, cross-cut by calcite veins. Grains

mostly (80%+) monocrystalline quartz, also chert,

carbonate, and trace plagioclase and tourmaline.

7.0 kg of rock was processed.
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

159

EMA (Key

Creek plate;

Port Road

succession of

Dumoulin and

others, 2004)

Noatak D-3

67°51'04"/

163°15'25"

1 Pa element fragment Bispathodus sp. (no

accessory denticles)

1 Pa element Hindeodus? sp. indet.

1 unassigned Pb element

1 Sb-Sc element Kladognathus sp. indet.

CAI=3

[DDH 1103, composite conodont sample 2: 674.5-

75.5, 676-76.3, 687-87.5, 688-90, and 690.5-91

ft; 33659-PC]

late Early to middle Late

Mississippian (Osageanearly Chesterian). Likely P.

mehli-Lower G. texanus

Zone (late Osagean) on the

basis of other conodont

collections from the top of

the Utukok Formation in

the Red Dog mine area.

Indeterminate (too few

conodonts);

postmortem transport

from or within a highenergy depositional

setting.

Uppermost Utukok Formation. See tables 6 and 11 for

additional samples from this drill hole.

674.5-691 ft: Very light- to medium-gray (outer),

medium-light- to medium-dark-gray (inner)

limestone. Several interbeds of medium-dark-gray to

black, noncalcareous shale as much as 3 ft thick and

~5% dark-brownish-gray shaly partings (2 mm-3.5

cm thick); local layers (1-30 cm thick) of chert and

partly silicified limestone (shale, chert, and silicified

limestone excluded from conodont sample).

Limestone is bioclastic pack/wackestone with

crinoid ossicles to 1.5 cm.

Thin section data:

679 ft: Crinoid pack/wackestone with crinoid ossicles

to 1.2 cm, lesser siliceous spicules, and abundant

stylolites. Matrix and bioclasts replaced by chert;

local dolomite rhombs in matrix.

687.5 ft: Skeletal supportstone with crinoid, bryozoan,

ostracode, and brachiopod fragments.

Heavy-mineral concentrate includes phosphatic and

phosphatized bioclasts (chiefly ichthyoliths) and

minor phosphatic brachiopod fragments.

6.9 kg of rock was processed.

Loc. 8 (app. 1) of Dumoulin and others (2004).
Table 7. Conodont samples from the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to

collector: AD, J.A. Dumoulin; AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; JS, J.M. Schmidt; KE, K. Evans; K.S., K.W. Sherwood; and TR, I.L. Tailleur. DDH, diamond drill hole. All drill hole samples collected by J.A. Dumoulin. Lithologic

data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

159

EMA (Key

Creek plate;

Port Road

succession of

Dumoulin and

others, 2004)

[cont.]

Noatak D-3

67°51'04"/

163°15'25"

1 P element of Eotaphrus burlingtonensis Pierce

and Langenheim

Kladognathus sp. indet.

 1 M, 1 Sa, and 6 Sb-Sc elements, and 1 fragment

32 indet. bar, blade, and platform fragments

CAI=3

[DDH 1103, composite conodont sample 3: 877-80,

881-84, 884.4-85.5, 886-886.3 ft; 33660-PC]

late Early Mississippian

(middle into late Osagean,

Sc. anchoralis-Do. latus

Zone into lower part of Po.

mehli-Lower G. texanus

Zone); this collection

indicates that at least part of

the upper Utukok does not

extend beyond the middle

part of the mehli-texanus

Zone.

Indeterminate (too few

conodonts). The

taphonomy of these

conodonts indicates

postmortem transport

within or from a highenergy, shallow-water

depositional setting.

Upper Utukok Formation. Beds fairly steeply dipping;

~110 ft of actual stratigraphic thickness estimated

between this sample and sample 2; total true

stratigraphic thickness of Utukok here probably

~300 ft. Depositional contact with Kayak Shale at

1272 ft.

877-886.3 ft.: Very light gray (outer), medium- to

medium-dark-gray (inner), fine- to coarse-grained

bioclastic limestone; mainly crinoidal supportstone

with local stylolites and sparry calcite veins.

Thin section data:

879 ft: Extensively dolomitized crinoidal limestone,

with bryozoan and brachiopod fragments and rare

phosphatic bioclasts.

885 ft: Crinoid grainstone with lesser bryozoan and

brachiopod fragments and articulated ostracodes.

Heavy-mineral concentrate includes phosphatized and

phosphatic bioclasts, chiefly ichthyoliths and minor

phosphatic brachiopod fragments.

7.0 kg of rock was processed.

167

KRA

(Eli plate)

Noatak D-5

67°50'24"/

163°20'42"

2 incomplete Pa elements Bispathodus aculeatus

(Branson and Mehl)

2 incomplete Pa elements Bispathodus stabilis

(Branson and Mehl)?

1 Pa element Clydognathus cavusformis Rhodes,

Austin, and Druce

8 subadult to adult Pa elements (mostly

incomplete) Patrognathus variabilis Rhodes,

Austin and Druce

2 Pa elements Polygnathus communis Branson and

Mehl

1 juvenile Pa element Siphonodella sp. of middlelate Kinderhookian morphotype [pl. 2, figs. 18,

19]

57 small indet. bar, blade, and platform elements

CAI=1.5

[81EK69C; 28583-PC]

early Early Mississippian

(middle-late

Kinderhookian).

High-energy, shallowwater depositional

regime.

Sandy limestone bed in quartzite.

This conodont fauna is similar to those from the Isikut

member of the Kayak Shale (Mull and others, 1997).

Fossil loc. 1, Mayfield and others (1987).
Table 8. Conodont samples from unnamed strata that may correlate with the Utukok Formation

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin.

Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

95

KRA

(Amphitheatre

plate)

De Long Mtns.

B-1

68°20'31"/

162°27'25.2"

3 incomplete Pa elements Bispathodus utahensis

Sandberg and Gutschick

Kladognathus sp.

 1 Pa-Pb, 1 Sa, and 3 Sc elements

Unassigned elements:

 1 Pb, 2 M (2 morphotypes), 2 Sb (2 morphotypes),

and 1 Sc

29 indet. bar, blade, and platform fragments

CAI=2.5-3.0

[04AD40H; 33785-PC]

middle Early-middle Late

Mississippian (latest

Kinderhookian-earliest

Chesterian; upper part Upper

Si. Isosticha-Si. crenulata

Zone through lower part Gn.

bilineatus-Upper

Cavusgnathus Zone).

Indeterminate (too few

identifiable

conodonts). Nearly all

conodonts in this

meager collection are

relatively tiny and

incomplete, indicating

postmortem transport,

likely from a shallowwater depositional

setting.

Sample from at or just above transitional top of map

unit Mls3 (shale and micritc limestone member) into

Mml3 (micritic limestone unit) of Lisburne Group

(Curtis and others, 1990). Sample taken ~60 to 70 m

above exposed base of Lisburne Group here. These

rocks are equivalent to the middle part of the Utukok

Formation in other plates of the KRA.

Sample from 15- to 25-cm-thick turbidite bed within a

sequence of sooty black shale and fine-grained

limestone. Turbidite consists of pyritic limestone

(crinoid packstone) with muddier lenses and clasts (to

25 cm long) of laminated mudstone/siltstone.

Heavy-mineral concentrate consists chiefly of

composite bioclastic carbonate-pyrite grains, lesser

pyritic phosphatic and pyritic bioclastic carbonate

grains, and minor phosphatized and phosphatic

bioclasts (mainly bryozoan fragments, lesser

ostracode valves, phosphatic brachiopod fragments,

and rare ichthyoliths and conodonts).

6.0 kg of rock was processed.

96

KRA

(Amphitheatre

plate)

De Long Mtns.

B-1

68°19'26"/

162°28'30"

Barren. Not surprising as 65% of the rock did not

dissolve.

[00AD8A]

Near structural base of map unit Mml3 (micritic

limestone unit) of Lisburne Group (Curtis and others,

1990).

Medium-olive-gray-weathering, moderately

bioturbated mudstone and lesser wackestone(?) in

beds 30- to 80-cm-thick with some 5-cm-thick

intervals of platy beds. Outcrop 3 to 5 m thick. Thin

section is bioturbated calcareous spiculite.

10.7 kg of rock was processed.

Loc. 24 (fig. 2) of Dumoulin and others (2004).

98

KRA

(Amphitheatre

plate)

De Long Mtns.

B-1

68°19'47.7"/

162°19'19.4"

Barren

[00AD12A]

Base of map unit Mml3 (micritic limestone unit) of

Lisburne Group (Curtis and others, 1990) in same

section as 00AD9A and 10A (loc. 99).

Stratigraphically overlies Devonian carbonate rocks;

see table 12 for additional sample from this locality.

Light- to medium-light-gray and grayish-orangeweathering, medium-dark-gray, massive- to thickbedded lime mudstone; no bioclasts noted. Thin

section is peloid-calcisphere supportstone.

11.2 kg of rock was processed.

Loc. 13 (app. 1) of Dumoulin and others (2004).
Table 8. Conodont samples from unnamed strata that may correlate with the Utukok Formation—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin.

Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

99

KRA

(Amphitheatre

plate)

De Long Mtns.

B-1

68°19'22"/

162°20'10"

Barren

[00AD9A]

Stratigraphic top of map unit Mml3 (micritic limestone

unit) of Lisburne Group (Curtis and others, 1990).

Underlies Kogruk Formation; see table 6 for a

Kogruk sample from this locality.

Light-gray- to medium-brownish-gray-weathering,

medium-dark-gray, bryozoan mudstone with

fenestrate bryozoan fragments as much as 5 cm long;

beds as much as 15-cm-thick at sample site, but a

meter lower bedding is platy and ≤1 mm in thickness.

Thin section is crinoidal wackestone-mudstone with

bryozoan fragments and calcareous and siliceous

sponge spicules.

8.7 kg of rock was processed.

Loc. 14 (app. 1) of Dumoulin and others (2004).

172

EMA (Key

Creek plate)

Noatak D-3

67°50'31"/

163°17'44"

7 Pa element fragments Hindeodus sp. indet.

Kladognathus sp. indet.

 6 M, 2 Sa, and 2 Sb-Sc element fragments

Unassigned elements:

 2 M, 2 Sa, and 2 Sc (2 morphotypes), all

fragments

107 indet. bar, blade, and platform fragments

CAI=3

[00AD23A; 33633-PC]

Early, but not earliest,

Mississippian (middle

Kinderhookian through at

least Osagean).

Indeterminate (too few

generically identifiable

conodonts).

The preservation of the

conodonts (all

fragments) and the

abundant ichthyoliths

in this residue suggest

a lag concentrate.

Unnamed limestone, ~150 ft thick, overlying Kayak

Formation; similar to Utukok Formation in lithofacies

and fauna and provisionally included in that unit by

Dumoulin and others (2004).

Medium-light-gray- and grayish-orange-weathering,

light-brownish-gray, crinoidal skeletal grainstone in

slabby beds 4 to 8 cm thick. Thin section is crinoidbryozoan grainstone with lesser ostracode and

brachiopod fragments and minor dolomite.

Heavy-mineral concentrate includes ichthyoliths and

indeterminate phosphatic fragments.

Original sample weight not recorded.

Loc. 10 (app. 1) of Dumoulin and others (2004).

1 Pa fragment Eotaphrus sp. indet.

1 juvenile Pa element Gnathodus sp. indet.

Kladognathus sp. indet.

 16 M, 1 Sa, and 17 Sb-Sc element fragments

Synclydognathus geminus (Hinde)

 1 Pa and 2 S and M elements

Unassigned elements:

 2 Pa (2 morphotypes--fragments), 9 Pb (3

morphotypes), 2 M (2 morphotypes),1 Sa, and 2

Sc (2 morphotypes, both fragments)

144 indet. bar, blade, and platform fragments

CAI=3

[00AD23B; 33634-PC]

late Early Mississippian

(Osagean, possibly middlelate Osagean)

A lag concentrate. Same unit and structural level as 00AD23A, but 40 ft

higher in section.

Lithofacies like 00AD23A but beds to 30 cm thick;

contains crinoid ossicles to 0.75 cm in diameter and

partly silicified rugose corals. Thin section is crinoidbryozoan grainstone with lesser gastropod(?) and

trilobite(?) fragments.

Heavy-mineral concentrate includes ichthyoliths and

indeterminate phosphatic fragments.

12.9 kg of rock was processed.
Table 9. Conodont samples from the Etivluk Group and Okpikruak Formation

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

JS, J.M. Schmidt; KE, K. Evans; and K.S., K.W. Sherwood. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin.

Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

36

PCA?

De Long Mtns.

B-2

68°21'46"/

162°50'12.7"

36 Pa element fragments Neogondolella navicula

(Huckriede) group

1 Sa element Neogondolella sp. indet.

CAI=2-2.5

[KS98-147B; Mes. 35020]

Middle-Late Triassic, most

likely middle Late Triassic.

Postmortem transport

within or from the

neogondolellid

biofacies as virtually

all specimens are

platform elements;

slope or basin

depositional setting.

Otuk Formation of Etivluk Group.

Buff-colored argillaceous carbonate rocks with locally

abundant shell fragments overlying sequence of red

and green cherts. Thin section is bivalve (monotid)

wackestone.

Heavy-mineral concentrate includes minor

phosphatized shell fragments and rare ichthyoliths.

8.8 kg of rock was processed.

Monotid bivalves and Palaeocardita(?) sp. of Late

Triassic age occurs in these strata (identified by R.B.

Blodgett, Oregon State University, unpublished fossil

report, 1999).

62

KRA?

De Long Mtns.

A-2

68°10'51"/

163°10'25.6"

Triassic conodonts:

4 juvenile and incomplete Pa elements

Neogondolella sweeti Kozur?

1 juvenile Pa element Neogondolella sp. indet.

Pennsylvanian conodonts:

2 juvenile Pa elements Declinognathodus

noduliferus (Ellison and Graves) subsp. indet.

(base of Pennsylvanian-early Desmoinesian)

Mississippian and (or) Pennsylvanian conodonts:

2 Pa element fragments of Cavusgnathus sp. indet.

or Adetognathus sp. indet. (late MeramecianChesterian or latest Chesterian-early Early

Permian)

1 Pa element fragment Rhachistognathus sp. indet.

(early Chesterian-early Atokan)

Mississippian conodonts:

2 Pa element fragments Gnathodus texanus

Roundy? (late Osagean-earliest Chesterian)

2 Sb-Sc Kladognathus sp. indet. elements (middle

Kinderhookian-Chesterian)

2 incomplete S elements Synclydognathus sp. indet.

(Osagean-earliest Chesterian)

1 unassigned M element

60 indet. bar, blade, and platform fragments

CAI=2.5-3

[98JS9N; Mes. 35021]

The collection contains

conodonts from at least three

sources. These are:

(1) middle Early Triassic

(Smithian) conodonts from

the Etivluk Group;

(2) earliest Early-Middle

Pennsylvanian (earliest

Morrowan-early

Desmoinesian) conodonts

from a correlative of the

Wahoo Limestone of the

Lisburne Group (possibly

the Nuka Formation); and

(3) Mississippian conodonts

from the Kogruk Formation

and (or) related units.

The Triassic conodonts

are normal-marine,

middle shelf to deeper

water forms. The

Pennsylvanian

conodonts are

characteristic of mainly

shallow-water, highenergy environments.

The Mississippian

conodonts include

shallow and deeper

water shelf species.

Boulder of heterolithic carbonate breccia within the

Jurassic-Cretaceous Okpikruak Formation. Main

lithology is ooid-skeletal packstone derived from the

Mississippian Kogruk Formation(?), but conodont

fauna indicates that younger carbonate lithologies

(probable Otuk Formation of the Etivluk Group and

possible Nuka Formation) are also present. See tables

6 and 7 for additional samples from this locality.

Boulder 3 m across of matrix-supported carbonate

breccia with lesser chert clasts; clasts 20-30%,

subrounded to subangular. Thin section is heterolithic

clastic carbonate; clasts chiefly ooid-bioclastic

packstone with dolomitic matrix and lesser ooid

grainstone.

Heavy-mineral concentrate is chiefly phosphatized

rock fragments.

5.4 kg of rock was processed.
Table 9. Conodont samples from the Etivluk Group and Okpikruak Formation —Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

JS, J.M. Schmidt; KE, K. Evans; and K.S., K.W. Sherwood. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin.

Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

66

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°10'18''/

162°50'48''

1 Pa element Neogondolella of the Neogondolella

navicula Group

CAI=2

[KE98-28; Mes. 35019]

Conodonts indicate a late

Middle-Late Triassic age,

but radiolarians restrict age

to middle Late Triassic (late

middle-early late Norian).

Indeterminate (too few

conodonts); most likely

normal-marine

depositional setting.

Otuk Formation (Etivluk Group). See table 14 for

radiolarian collection from this locality.

Olive-gray, very fine grained dolostone(?) interbedded

with radiolarian chert. Carbonate beds contain rare

thin bivalve shells identified as Monotis(?) sp. of Late

Triassic age by R.B. Blodgett (Oregon State

University, unpublished fossil report, 1999). Thin

section is very fine crystalline dolomite mosaic with

minor intercrystalline quartz and a few thin bivalve

shells partly replaced by quartz and phosphate.

6.0 kg of rock was processed.

67

EMA

(Wolverine

Creek plate;

Mt. Raven

window)

De Long Mtns.

A-2

68°11'39"/

162°40'27.8"

Barren

[99AD14Z]

Sample from basal Siksikpuk Formation depositionally

overlying Lisburne Group; upper Lisburne succession

here much like that at 99AD13 (loc. 42, table 6).

Sample from 10- to 20-cm-thick beds of light-gray- to

moderate-brown-gray-weathering, dark-gray, finegrained, peloidal(?) carbonate rock interbedded with

greenish-gray siltstone. Thin section is fine-grained

impure carbonate, possibly altered (calcitized)

volcanic(?) rock.

8.43 kg of rock was processed.

Loc. 6 (fig. 2) of Dumoulin and others (2004).

126

EMA

(Wolverine

Creek plate)

De Long Mtns.

A-2

68°09'20"/

163°01'40"

Barren

[DDH 927 (west of Anarraaq deposit) composite

conodont sample: 1693.2-94.2, 1695-95.3, 1696.5-

97, 1699-99.5, 1699.7-1700.7, 1701.2-01.4,

1701.5-03 ft]

Sample from upper subunit of Otuk Formation (Etivluk

Group) ~72 ft below conformable contact with

overlying Kingak Formation(?) and ~3 ft above

faulted contact with middle subunit of Otuk. See table

14 for radiolarian collection from this locality.

1693-1703 ft: Very light to medium-light-gray (outer),

medium-gray (inner), very fine grained, locally cherty

carbonate with concentrations of monotid bivalves

and dark shaly layers a few centimeters thick (shalier

and chertier intervals not sampled). Thin section at

1699.5 ft is argillaceous, dolomitic(?) micrite with

sparse small shell fragments, spines, and radiolarians;

some bioclasts partly silicified.

4.5 kg of rock was processed and analyzed by Andrea

Krumhardt, University of Alaska (Fairbanks).
Table 9. Conodont samples from the Etivluk Group and Okpikruak Formation —Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

JS, J.M. Schmidt; KE, K. Evans; and K.S., K.W. Sherwood. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin.

Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

127

EMA

(Wolverine

Creek plate)

De Long Mtns.

A-2

68°09'40"/

163°00'20"

Barren

[DDH 1110 (west of Anarraaq deposit) composite

conodont sample: 2080.6-82.3, 2083-83.5, 2084.7-

85.2, 2087-89 ft]

Sample from upper subunit of Otuk Formation (Etivluk

Group) ~34 ft below conformable contact with

overlying Kingak Formation(?). Contact with middle

subunit of Otuk not penetrated in this drill hole; upper

subunit is at least 156 ft thick.

2080-2089 ft: Light-gray (outer), medium-dark- to

medium-olive gray (inner), very fine grained cherty

carbonate with local lenses of thin shells (mainly

monotid bivalves) and irregular layers a few

centimeters thick of medium-gray radiolarian chert

and medium-dark-gray shale (chert and shale not

sampled).

Thin section data:

2080.9, 2083. 5 ft: argillaceous, cherty, dolomitic

micrite with locally abundant monotid bivalve

fragments and sparse, poorly preserved radiolarians.

4.0 kg of rock was processed and analyzed by Andrea

Krumhardt, University of Alaska (Fairbanks).
Table 10. Conodont samples from the Nuka Formation and related rocks

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. NRA, Nuka Ridge allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; and Cx, S.M. Curtis. Lithologic data

under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

16

Olistolith

derived from

NRA

De Long Mtns.

A-3

68°08'00"/

163°38'42"

3 Pa element fragments Gnathodus bilineatus

(Roundy)

2 juvenile Pa elements Gnathodus girtyi Hass subsp.

indet.

2 Pa element fragments Gnathodus spp. indet.

1 subadult Pa element Idiognathodus sp.

1 Pb element Idioprioniodus sp.

21 indet. bar, blade, and platform fragments

CAI=2.5-3

[79CX125H-1; 27552-PC]

No older than late Morrowan

(early Middle

Pennsylvanian); the fauna

contains mainly Chesterian

conodonts with an

Idiognathodus of no older

than earliest Middle

Pennsylvanian age.

Indeterminate (mixed

age-redeposited fauna);

the Late Mississippian

and Pennsylvanian

conodonts are all

normal-marine

relatively shallowwater forms.

Nuka Formation.

This fauna resembles those collected by J. Siok in

the Killik River quadrangle from a 2-m-thick

phosphatic interval at the top of the Lisburne

Group. The interval contains redeposited

conodonts of Mississippian and Early and Middle

Pennsylvanian age and is no older than

Desmoinesian (late Middle Pennsylvanian) and no

younger than Leonardian (late Early Permian).

Fossil loc. 22, Mayfield and others (1990).

118

NRA (Bastille

plate)

Misheguk Mtn.

B-5

68°19'58.6"/

161°37'04"

Barren. No conodonts or other phosphatic or

phosphatized fossil materials were found.

[03AD34C]

Mississippian and (or) Devonian limestone (map

unit MDl5) of Curtis and others (1984). These

authors report Devonian corals from <0.5 mi to

the southwest in this unit (fossil loc. 61), and

Middle to early Late Devonian (Frasnian or older)

brachiopods and corals from ~1 mi to west (fossil

loc. 59). Unit here is ~80 to 100 m thick and is

mostly dolostone with some limestone intervals.

Sample from 8-cm-thick bed at base of 30 cm

interval of brown-gray limestone that weathers

very pale yellow brown. Beds thin upward to 5

and then 3 cm thick. Skeletal supportstone with

ostracodes(?). Thin section is partly dolomitized

skeletal packstone; bioclasts mainly small

brachiopods and (or) ostracodes.

6.45 kg of rock was processed.

119

NRA (Bastille

plate)

Misheguk Mtn.

B-4

68°28'55"/

161°19'47"

Barren. No conodonts or other mineralized fossil

materials were found.

[00AD27A]

Mississippian and (or) Devonian limestone (map

unit MDl5) of Curtis and others (1984). Outcrop

on lower slopes of Copter Peak; sample ~50 to100

m below base of Etivluk Group.

Sample from 30x60-cm lens of skeletal grainstone

within laminated carbonate sequence. Grainstone

is medium-dark-gray-weathering, medium-browngray, and poorly sorted with some lithic grains

and mud clasts to 1 cm long. Thin section is

dolomitic, recrystallized(?) crinoidal supportstone.

9.7 kg of rock was processed.
Table 11. Conodont samples from the Endicott Group

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; and MD, C.F. Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A.

Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

13

PCA (Amaruk

plate)

De Long Mtns.

A-3

68°08'38.4"/

163°38'40.2"

1 M element Kladognathus sp. indet.

1 posterior Pa element fragment

Pseudopolygnathus sp. indet. of Mississippian

morphotype

2 indet. bar or blade fragments

5 ichthyoliths

CAI=2.5-3

[79CX127G]

Early, but not earliest,

Mississippian (middle

Kinderhookian-Osagean).

Indeterminate (too few

conodonts).

Kayak Shale.

Fossil loc. 18, Mayfield and others (1990).

15

PCA (Amaruk

plate)

De Long Mtns.

A-3

68°07'40.7"/

163°43'04.8"

5 robust Pa elements Bispathodus stabilis (Branson

and Mehl)

1 Sb-Sc element Kladognathus sp. indet.

10 Pa elements Polygnathus communis Branson

and Mehl

1 Pa element Polygnathus sp.

3 Pa elements Pseudopolygnathus sp.

15 Pa elements Siphonodella spp. of middle-late

Kinderhookian morphotype

9 Pa element large fragments Siphonodella spp.

Unassigned elements:

 1 Pb, 1 M, 1 Sa, 1 Sb, and 3 Sc (3 morphotypes)

86 indet. bar, blade, and platform fragments

CAI=2.5-3

[79MD171D; 27559-PC)

early Early Mississippian

(middle-late

Kinderhookian).

Siphonodellidpolygnathid biofacies;

open-marine middleshelf or deeper water

depositional setting.

The size of the

conodonts suggests a

lag concentrate.

Kayak Shale.

Conodont assemblage is most similar to those from the

Rough Mountain Creek unit of the Lisburne Group

(Dumoulin and Harris, 1997) and from open-marine

facies of the Utukok Formation.

Fossil loc. 31, Mayfield and others (1990).
Table 11. Conodont samples from the Endicott Group—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; and MD, C.F. Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A.

Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

86

EMA

(Wolverine

Creek plate;

Rok window)

De Long Mtns.

A-2

68°01'17.6"/

162°47'37.8"

1 unassigned M element of post-Silurian

morphotype

8 indet. bar, blade, and platform fragments

CAI=3-3.5

[97AK4]

Conodonts in this collection

merely indicate a postSilurian Paleozoic age.

However, all other fossil

collections from the Kayak

in the western and central

Brooks Range that have

produced

biostratigraphically useful

fossils restrict the age of the

formation to the early Early

Mississippian

(Kinderhookian).

Indeterminate (no

generically identifiable

conodonts).

Upper part of Kayak Shale, from limy interval ~1 m

thick, overlying ~10 m of interbedded dark gray

argillite and yellow-green-weathering siltstone and

very fine grained sandstone.

Sample from brown-yellow-weathering, iron-stained,

impure fossiliferous limestone. Thin section is

skeletal wackestone/packstone, made up of crinoid

and lesser bryozoan fragments, sponge spicules

(calcareous and siliceous), brachiopods, ostracodes,

and gastropods(?). Bioclasts (30-50% of slide)

concentrated into vague layers; matrix is brown,

noncalcareous mudstone with less than 10% quartz

silt. Bioclasts abraded, some partly replaced by

pyrite. One rounded lithoclast (8 mm diameter)

contains abundant calcareous spicules to 800 μ

(including one biaxial spicule).

Heavy-mineral concentrate contains phosphatic and

phosphatized, partly pyritized and ferruginous

bioclasts (including brachiopods and spine and tube

steinkerns) and minor euhedral pyrite.

7.0 kg of rock was processed.

Synclydognathus n. sp.

 13 Pa, 4 Pb, and 7 S and M elements

33 indet. bar, blade, and platform fragments

CAI=3-3.5

[97AK5; 33393-PC]

Early, but not earliest,

Mississippian (middle

Kinderhookian through

Osagean).

Synclydognathid

biofacies; normalmarine, near restricted,

probably shallowwater depositional

setting.

Upper part of Kayak Shale(?); thicker limestone

overlying 97AK4.

Sample from medium-gray, fossiliferous limestone in

3- to 40-cm-thick beds with prominent crosslaminae, ripples, and partings of sooty, black,

calcareous shale. Thin section is similar to 97AK4

but lacks quartz silt. Skeletal wackestone/packstone;

bioclasts 30-40%, chiefly <4 mm, include crinoid

ossicles, lesser brachiopods, bryozoans, calcareous

and siliceous spicules, and thin-shelled, articulated

ostracodes. Most bioclasts broken and abraded.

Local thin lenses rich in calcareous spicules.

Heavy-mineral concentrate is chiefly ferruginous

bioclasts and composite grains and lesser phosphatic

and phosphatized bioclasts (brachiopods, ostracodes,

and ichthyoliths).

15 kg of rock was processed.
Table 11. Conodont samples from the Endicott Group—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; and MD, C.F. Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A.

Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

90

EMA

De Long Mtns.

A-2

68°02'38.2"/

162°36'9.5"

Barren

[97AK115A]

Hunt Fork Shale.

Ripple-laminated, very fine to fine-grained sandstone,

locally calcareous with rare brachiopods, in 0.5- to

1-m-thick beds. Thin section is very fine grained

sandstone, fairly well sorted, with a few crenulated

brachiopods; notable red-brown iron-rich material

between (and replaces?) grains. Clasts are ~50%

monocrystalline quartz, lesser chert, polycrystalline

quartz, mafic volcanic lithoclasts (including tuff

fragments?), and trace phosphate(?).

7.0 kg of rock was processed.

103

EMA (Key

Creek plate)

De Long Mtns.

B-1

68°21'21"/

162°02'16"

Barren

[00AD17A]

Uppermost Kayak Formation stratigraphically below

contact with Kuna Formation; see table 1 for Kuna

samples from this locality.

Sample from limy concretions (10- to 30-cm diameter)

50 to 180 cm below top of Kayak along August

Creek. Medium-gray- to grayish-orange-weathering,

medium-gray to medium-dark-gray, very fine

grained limestone. Thin-section is calcareous

spiculite.

Heavy-mineral concentrate includes pyritized spicules.

10.8 kg of rock was processed.

Loc. 2 (app. 1) of Dumoulin and others (2004).

105

EMA (Key

Creek plate)

De Long Mtns.

B-1

68°16'34" /

162°09'14.4"

Barren

[97AK55C]

Upper part of Noatak Sandstone, below contact with

Kayak Shale.

Fine to very fine grained quartz sandstone with local

trough cross-beds, asymmetric ripples, burrows, and

sparse mud chips. Thin section is fine-grained

quartz>chert sandstone with silica cement. Clasts

~75% monocrystalline quartz, with minor dolomite,

metamorphic and sedimentary lithoclasts, and

polycrystalline quartz.

Heavy-mineral concentrate includes phosphatic

bioclasts (brachiopod fragments) and rare

subrounded to well-rounded stable heavy minerals.

5.9 kg of rock was processed.
Table 11. Conodont samples from the Endicott Group—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; and MD, C.F. Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A.

Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

115

EMA (Key

Creek plate)

De Long Mtns.

A-1

68°08'10"/

162°30'48"

5 mid-Pa element fragments of the Bispathodus

aculeatus (Branson and Mehl) group

Unassigned elements:

 1 M, 1 Sa, and 1 Sc (fragments)

14 indet. bar, blade, and platform fragments

CAI=3

[79EK274A]

latest Late Devonian-early

Early Mississippian (late

Famennian-Kinderhookian).

Indeterminate (too few

conodonts); conodonts

that are present

indicate a high-energy,

shallow-water

depositional setting.

Calcareous sandstone interval in Kayak Shale;

underlies Kuna Formation (Lisburne Group).

Fossil loc. 9, Curtis and others (1990).

158

EMA (Key

Creek plate)

De Long Mtns.

A-2

68°05'08.2"/

162°45'37.1"

11 Pa element fragments of a double-row

bispathodid

1 Pa element fragment of a single-row bispathodid

Kladognathus sp. indet.

 1 P, 4 M, 1 Sa, and 2 Sb-Sc element fragments

1 Pa element Polygnathus inornatus E.R. Branson

1 Pa element fragment Polygnathus sp. indet.

1 unassigned Sc element

1 phosphatized ammonoid steinkern

CAI=3

[DDH 587 (E-NE of Red Dog Main deposit),

composite conodont sample: 1764.7-66.7, 1770.6-

74.7, and 1775.0-76.0 ft; 33487-PC]

early Early Mississippian

(Kinderhookian).

Postmortem transport

within or from a

bispathodidkladognathid biofacies;

likely postmortem

transport from a

normal-marine

shallow-water

depositional setting.

Kayak Shale, several hundred m below contact with

Kuna Formation; Kayak in this drill hole may be

structurally thickened. See table 3 for Kuna sample

from this drill hole.

1764.7-1776.0 ft: Irregular laminae and beds (0.1-5 cm

thick) of mudstone, siltstone, noncalcareous and

calcareous sandstone. Clastic strata have salt-andpepper color of medium-dark-gray to very light gray

(outer). Limy beds contain scattered small (0.5 cm

diameter) solitary corals and pelmatozoan debris.

Thin section data:

1765.4, 1770.2: Fine-grained quartz sandstone with

patchy carbonate cement and bioclasts.

1772 and 1774.4: Crinoid grainstone with ≤25% quartz

sand. Noncarbonate grains include chert, mica, and

metamorphic and sedimentary lithic clasts.

Heavy-mineral concentrate includes scarce

phosphatized bryozoan fragments and ichthyoliths.

7.54 kg of rock was processed.
Table 11. Conodont samples from the Endicott Group—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; and MD, C.F. Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A.

Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

159

EMA (Key

Creek plate;

Port Road

succession of

Dumoulin and

others, 2004)

Noatak D-3

67°51'04"/

163°15'25"

5 Pa element fragments Bispathodus stablis

(Branson and Mehl) or Bi. utahensis Sandberg and

Gutschick

1 M element Idioprioniodus conjunctus

Kladognathus sp. indet.

 10 M, 4 Sa, and 17 Sb-Sc elements, and 4

fragments

1 unassigned M and 1 Sa elements

46 indet. bar, blade, and platform fragments

CAI=~3

[DDH 1103, composite conodont sample 4: 1376.2-

76.4, 1376.6-76.7, 1377.2-77.6, 1379.5-79.8,

1381.5-82.5, 1383.2-83.6, 1385.6-86; 1386.1-

86.5, 1404.4-06.5, 1421-22.2 ft; 33661-PC]

Early Mississippian (late

Kinderhookian-middle

Osagean); upper age

constraint based on

conodonts from overlying

Utukok Formation.

Postmortem transport

within or from a

kladognathid biofacies.

This sample represents

a phosphatic lag

concentrate.

Kayak Shale, below contact with Utukok Formation at

~1272 ft. See tables 6 and 7 for additional samples

from this drill hole.

1376.2-1422.2 ft: Black to grayish-black to mediumdark-gray noncalcareous shale and mudstone with

waxy to shiny luster, interbedded with very light

gray to medium-gray (outer), medium- to mediumdark-gray (inner) bioclastic (crinoidal) limestone;

limestone in graded layers 2 cm to 2 ft thick that are

locally bioturbated (shale not sampled for

conodonts).

Thin section data:

1376 ft: Dark shale with laminae 1-5 mm thick of

calcareous and siliceous spicules.

1376.2 ft: Dark shale with a partly silicified layer rich

in crinoid fragments with lesser spicules.

1380 ft: Graded crinoid packstone with brachiopods,

noncarbonate mud matrix, and fitted fabric.

1387 ft: Skeletal-intraclast grainstone with crinoids,

bryozoans, brachiopods, and phosphatic bioclasts.

1403 ft: Partly bioturbated bryozoan-crinoid

supportstone with seams of dark shale.

Heavy-mineral concentrate is chiefly variably pyritic,

partly phosphatic, very fine grained siliciclastic rock

fragments, phosphatic and phosphatized bioclasts

(chiefly ichthyoliths, minor brachiopods and

gastropod steinkerns), anhedral pyrite, and scarce

pyritized ostracode valves.

7.9 kg of rock was processed.

175

EMA (Key

Creek plate)

Noatak D-2

67°58'36"/

162°50'00"

1 gerontic Pa element Bispathodus stabilis

(Branson and Mehl)

3 Pa elements Patrognathus variabilis Rhodes,

Austin and Druce [pl. 3, figs. 7, 8]

11 Pa elements Polygnathus communis Branson

and Mehl [pl. 3, figs. 3, 4]

1 unassigned M element

31 indet. bar, blade, and platform fragments

CAI=4-4.5

[81EK75F; 28584-PC]

early Early Mississippian

(Kinderhookian).

Mixed shelfal, likely

shallow-water

biofacies

Sandstone member of Kayak Shale, above Kanayut

Conglomerate.

Limy, ferruginous encrinite interbedded with siltstone

and sandstone.

Heavy-mineral concentrate contains abundant

phosphatized steinkerns of a variety of ostracodes

and gastropods.
Table 11. Conodont samples from the Endicott Group—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; PCA Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin;

AK, J.S. Kelley; Cx, S.M. Curtis; EK, I. Ellersieck; and MD, C.F. Mayfield. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A.

Dumoulin and (or) A.G. Harris. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional

environment

Remarks

177

EMA (Key

Creek plate)

Noatak C-4

67°37'05.1"/

163°42'17.2"

1 Bispathodus aculeatus aculeatus (Branson and

Mehl)

6 Pa elements Bispathodus stabilis (Branson and

Mehl)

8 Pa elements (juveniles and fragments)

Clydognathus? sp. or Patrognathus variabilis

Rhodes, Austin and Druce

88 Pa elements Polygnathus communis Branson

and Mehl

3 Pa elements Polygnathus inornatus E.R. Branson

7 Pa elements (mostly fragments)

Pseudopolygnathus orthoconstrictus (Thomas)?

Unassigned elements:

 7 M, 2 Sa, and 1 Sc

5 indet. bar, blade, and platform fragments

CAI=4.5

[81EK108D; 28366-PC)

early Early Mississippian

(Kinderhookian).

Taxa are typical of very

shallow-water, often

quartz-sand-bearing

strata.

Kayak Shale.

Sandy encrinite interbedded with marine sandstone and

siltstone.

Fauna is similar to that of Isikut member of the Kayak

Shale (Mull and others, 1997, Table 1, collns.

92TM17A, 93TM35L, 93TM35C).

178

EMA (Key

Creek plate)

Noatak C-4

67°36'12"/

163°51'18"

Collection contains predominantly juveniles and

small fragments.

1 Pa element fragment Bispathodus stabilis

(Branson and Mehl) or Bi. utahensis Sandberg and

Gutschick

Hindeodus sp. indet.

 4 Pa and 1 Sb elements

1 large Pa element Polygnathus inornatus E.R.

Branson

3 Pa elements Polygnathus sp. indet. (juveniles and

fragments)

1 juvenile Pa Pseudopolygnathus sp. indet.

Synclydognathus geminus (Hinde)

 1 Pb and 1 Sa elements [pl. 3, figs. 5, 6]

Unassigned elements:

 4 M (2 morphotypes) and 3 Sc (3 morphotypes)

43 small indet. bar, blade, and platform fragments

CAI=4.5-5

[81MD41E; 28367-PC]

early Early Mississippian

(middle-late

Kinderhookian).

Size and condition of

conodonts indicates a

winnow from a

shallow-water, normalmarine environment.

Kayak Shale.

Rubbly subcrop of gray limestone interbedded with

siltstone.
Table 12. Conodont samples from Devonian carbonate rocks

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; AK,

J.S. Kelley; Cx, S.M. Curtis; MD, C.F. Mayfield; and RB, R.B. Blodgett. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

Structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional environment

Remarks

11

PCA

De Long Mtns.

A-3

68°10'12"/

163°28'42"

1 Dvorakia? sp. indet.

12 I elements Icriodus symmetricus Branson and

Mehl?

16 I element fragments Icriodus sp. indet.

2 Pa elements Polygnathus cristatus Hinde

1 Pa element fragment Polygnathus cf. Po.

latifossatus Wirth

9 Pa element fragments Polygnathus linguiformis

linguiformis Hinde

Unassigned elements:

1 M and 2 Sc

70 indet. bar, blade, and platform fragments

CAI=3.5

[8-16-83M; 10860-SD]

late Middle Devonian

(early-late Givetian;

upper Po. varcus

Subzone through at least

K. disparilis Zone).

Icriodid biofacies; highenergy reef to near reef

and shoal depositional

setting.

Medium-light-gray, medium-gray- and grayish-orangeweathering, massive-bedded, crinoidal, bioclastic

grainstone. Thin section is partly dolomitized,

loosely packed crinoid grainstone with rare bryozoan

and brachiopod fragments. Crinoid ossicles (to 5 mm

in diameter) make up 80-90% of bioclasts.

5.9 kg of rock was processed.

Sample collected by A.G. Harris.

12

PCA (Amaruk

plate)

De Long Mtns.

A-3

68°10'14.6"/

163°26'13.4"

4 Pa element fragments Polygnathus spp. indet. of

Devonian morphotype

11 indet. bar, blade, and platform fragments

CAI=3-4

[79MD116B]

Middle and (or) Late

Devonian (Eifelianmiddle Frasnian and

(or) Famennian, but not

late Frasnian).

Indeterminate (too few

conodonts); taxa present

and their condition

indicate postmortem

transport within or from a

shelf, probably a highenergy environment.

Fossil loc. 28, Mayfield and others (1990).

14

PCA

De Long Mtns.

A-3

68°08'12"/

163°41'06"

5 indet. bar, blade, and platform fragments of postEarly Ordovician morphotype

CAI=3.5

[8-16-83L]

Middle OrdovicianPermianIndeterminate (too few

conodonts).

Outcrop consists of 85% calcareous shale and 15%

slightly argillaceous, very fine grained, rippled,

medium-gray, light-gray- to yellowish-grayweathering limestone with flute casts. Thin section is

pelloidal, ferroan calcisiltite with seams rich in

ferroan dolomite, quartz, feldspar, and white mica.

5.78 kg of rock was processed.

Sample collected by A.G. Harris.
Table 12. Conodont samples from Devonian carbonate rocks—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector: AD, J.A. Dumoulin; AK, J.S. Kelley: Cx, S.M. Curtis: MD, C.F.

Mayfield; and RB, R.B. Blodgett. CAI, conodont color alteration index. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

Structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional environment

Remarks

26

KRA

De Long Mtns.

A-3

68°05'42"/

163°27'42"

Polygnathus cooperi cooperi Klapper

 81 Pa, 5 Pb, 10 M, 4 Sa, 3 Sb, and 4 Sc elements

247 indet. bar, blade, and platform fragments

CAI=3.5

[8-16-83I; 10859-SD]

very latest Early-early

Middle Devonian (latest

Emsian-early Eifelian;

Po. serotinus Zone-Po.

costatus costatus Zone).

Polygnathid biofacies; shelf

or platform depositional

setting. The preservation

of this collection indicates

a relatively high-energy

environment and

therefore shallow water.

Fossiliferous, crinoidal, medium-light-gray, light-grayweathering packstone. From talus block on slope of

mountain at 1250 ft. Thin section is coarse-grained

pelmatozoan packstone with lesser brachiopods;

largely dolomitized matrix.

7.4 kg of rock was processed.

Sample collected by A.G. Harris.

27

KRA

De Long Mtns.

A-3

68°05'32"/

163°27'54"

Polygnathus linguiformis Hinde

 8 Pa, 1 M, and 1 Sb (mostly fragments)

77 indet. bar, blade, and platform fragments

CAI=3-3.5

[8-16-83H; 10858-SD]

very latest Early-early

early Late Devonian

(latest Emsian-early

Frasnian; Po. serotinus

Zone-Lower Pa. hassi

Zone).

Indeterminate (too few

conodonts); postmortem

transport within or from

the polygnathid biofacies,

probably normal-marine,

shallow-water

depositional environment.

Medium-gray, fine-grained, fossiliferous, rubbly and

massive-bedded limestone. Thin section is packed,

skeletal-pelloidal packstone. Bioclasts include

pelmatozoan, bryozoan, and brachiopod fragments;

many clasts abraded and micritized.

5.1 kg of rock was processed.

Sample collected by A.G. Harris.

28

KRA

De Long Mtns.

A-3

68°05'03"/

163°28'53.5"

1 posterior fragment Pa element Polygnathus

linguiformis Hinde

1 Pa element Polygnathus pseudofoliatus

Wittekind

1 indet. bar fragment

CAI=3

[84RB118]

late Middle Devonian

(lower half of Givetian;

Lower-Middle P. varcus

Subzones), based on

overlapping ages of

brachiopods and

conodonts. Polygnathus

pseudofoliatus ranges

from the T. k. australis

Zone into the Middle P.

varcus Subzone.

Likely a polygnathid

biofacies; probable

normal-marine

depositional environment.

Dark-gray lime mudstone with common silicified

fossils, including brachiopods (predominantly

stringocephalids), stromatoporoids, solitary rugose

corals, and gastropods. The brachiopods indicate a

Givetian age (Blodgett and Dutro, 1992).

29

KRA (Wulik

Peaks plate)

De Long Mtns.

A-3

68°04'59"/

163°21'59.6"

Barren

[99AD22A]

Massive, castle-forming, light-gray-weathering, darkgrayish-brown micritic limestone with rare small

bioclasts and clasts(?), slightly fetid, in 30- to 50-

cm-thick beds. Thin section is peloidal-skeletal

supportstone.

This unit intruded by mafic dike(?) (map unit JPm4 of

Mayfield and others, 1990) ~0.6 mi southwest of this

locality.

9.35 kg of rock was processed.
Table 12. Conodont samples from Devonian carbonate rocks—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector: AD, J.A. Dumoulin; AK, J.S. Kelley: Cx, S.M. Curtis: MD, C.F.

Mayfield; and RB, R.B. Blodgett. CAI, conodont color alteration index. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

Structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional environment

Remarks

97

KRA

(Amphitheatre

plate)

De Long Mtns.

B-1

68°20'19.2"/

162°18'15.2"

2 posterior Pa element fragments Polygnathus sp.

indet. of Middle Devonian-late Late

Mississippian morphotype

1 unassigned Sc element

1 indet. bar fragment

CAI=3

[79MD47]

Middle Devonian-late

Late Mississippian.

Indeterminate (too few

conodonts).

Fossil loc. 10, Curtis and others (1990).

98

KRA

(Amphitheatre

plate)

De Long Mtns.

B-1

68°19'47.7"/

162°19'19.4"

2 indet. bar and blade fragments

CAI=3

[00AD13A]

Devonian-Mississippian Indeterminate (too few

conodonts).

Top of Devonian(?), overlain at this locality by the

micritic limestone unit of the Lisburne Group (see

table 8 for sample from this unit).

Crudely massively bedded, medium-gray-weathering,

dark-gray lime mudstone with dark-yellowish-gray

mottles(?) or zones. Thin section is peloidal

supportstone with rare calcispheres.

9.4 kg of rock was processed.

101

KRA (Kelly

plate)

De Long Mtns.

B-1

68°21'3.7"/

162°12'12.1"

5 Pa elements Polygnathus angusticostatus

Wittekindt

Vicarious elements of Polygnathus spp.:

 2 M, 1 Sb, and 5 Sc (2 morphotypes) elements

 2 Pa element fragments Polygnathus sp. indet.

20 indet. bar, blade, and platform fragments

CAI=3-3.5

[99AD17A; 12673-SD]

middle Middle Devonian

(middle Eifelian into

earliest Givetian). Po.

angusticostatus is

known to range from the

T. k. australis Zone

through(?) the Po. x.

ensensis Zone.

Indeterminate (too few

conodonts), but likely a

relatively shallow water

shelf or platform

depositional setting.

Sample taken near base of 6-m-thick outcrop. Late

Middle Devonian brachiopods (fossil loc. 38 of

Curtis et al., 1990) near here.

Grayish-black, medium-gray-weathering, fetid,

dolomitic lime mudstone in uneven 5- to 7-cm-thick

nodular beds. Thin section is a fine-grained, euhedral

dolomite mosaic.

10.9 kg of rock was processed.

104

KRA (Kelly

plate)

De Long Mtns.

B-1

68°18'52.6"/

162°08'59.3"

9 Pa incomplete elements Apatognathus varians

Branson and Mehl

1 Pa element Polygnathus communis communis

Branson and Mehl

5 Pa elements Polygnathus semicostatus Branson

and Mehl

Unassigned elements:

1 Pa (fragment), 2 Pb, and 1 Sc

50 indet. bar, blade, and platform fragments

CAI=3

[79CX60A; 10013-SD]

late Late Devonian

(Famennian, not earliest

or latest; within Middle

Pa. crepida Zone to

within Lower Si.

praesulcata expansa

Zone).

Indeterminate (too few

conodonts); species that

are present indicate a

shallow- to middle-shelf

depositional setting.

2.3 kg of rock was processed.

Fossil loc. 12 of Curtis and others (1990).
Table 12. Conodont samples from Devonian carbonate rocks—Continued.

[All faunas identified by A.G. Harris. Structural units determined by L.E. Young. KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector: AD, J.A. Dumoulin; AK, J.S. Kelley: Cx, S.M. Curtis: MD, C.F.

Mayfield; and RB, R.B. Blodgett. CAI, conodont color alteration index. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; indet., indeterminate; loc., locality]

Locality No.,

Structural unit

Quadrangle,

latitude n./

longitude w.

Conodont fauna and CAI

[field No.; USGS collection No.]

Age Conodont biofacies and

depositional environment

Remarks

108

KRA

De Long Mtns.

A-1

68°14.'54"/

162°14'30"

Barren

[97AK61A]

Sample taken near base of ~500-ft-thick measured

section of Devonian limestone overlain by Utukok

Formation; see table 7 for Utukok samples from this

locality.

Light-medium-gray-weathering, medium-gray

limestone with local gastropods and shell hash. Thin

section is micrite with <10% bioclasts, including

calcispheres, lesser ostracodes, and calcareous

spicules(?). Local lenses of peloidal supportstone;

peloids 20-60 μm, rarely to 300 μm. Abundant

calcite veins, and some stylolites with trace quartz

silt.

7.2 kg of rock was processed.

1 indet. conodont fragment

CAI=~3

[97AK62]

Ordovician-Permian Indeterminate. Sample taken ~160 ft above 97AK61A.

Light-medium-gray-weathering, medium-light-gray to

medium-gray limestone with possible peloids,

bioclasts, and symmetrical ripples. Thin section is

peloidal supportstone grading to micrite. Trace

quartz silt along stylolites and abundant calcite

veins. Less than 5% bioclasts, mostly calcispheres.

Possible fenestrae to 500 μm filled with calcite spar.

Trace dolomite rhombs replaced by silica.

5.6 kg of rock was processed.

1 indet. bar or blade fragment

1 ichthyolith

CAI=3

[97AK63]

Devonian-Permian Indeterminate. Sample taken ~100 ft above 97AK62. Limestone

similar to that at 97AK61 and 62. Thin section is

skeletal-peloidal-mud lump packstone with lenses of

grainstone. Bioclasts include calcispheres,

brachiopods(?), and abundant algae(?). Some

algae(?) have bored micritic rims.

7.3 kg of rock was processed.

109

KRA (Kelly

plate)

De Long Mtns.

A-1

68°14'31.6"/

162°05'31.2"

No conodonts or other phosphatic or phosphatized

fossils were found.

[03AD23A]

Medium- to medium-light-gray dolostone, weathers

light gray, with very fetid (petroliferous) odor.

Outcrop ~0.5 m thick; cut by numerous calcite and

quartz veins. Many fractures contain abundant, large

patches of dead oil. Beds ~10 cm, uneven. Locally

abundant corals and amphiporid stromatoporoids.

Thin section is dolomite mosaic with ghostly

bioclasts, probably mostly Amphipora sp.

6.4 kg of rock was processed.
Table 13. Conodont samples from the Noatak quadrangle

[All faunas identified by A.G. Harris. +Structural unit determined by L.E. Young. All other structural and stratigraphic units as reported by C.F. Mayfield and co-workers. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; NRA, Nuka

Ridge allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: EK, I. Ellersieck; MD, C.F. Mayfield; and TR, I.L. Tailleur. *, age revised by A.G. Harris in 2000. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Age of conodont fauna and CAI

[field No.; USGS collection No.]

Stratigraphic unit Remarks

161

KRA (Kelly

plate)

Noatak D-6

67°57'34.5"/

164°40'30"

Late Mississippian-early Early Permian*

CAI=1-1.5

[81MD29C; 28585-PC]

Kogruk Formation Limestone with gray chert.

Fossil loc. 5 in Mayfield and others (1987).

162

KRA (Kelly

plate)

Noatak D-6

67°57'00"/

164°39'06"

Late Mississippian (late Meramecian-late Chesterian)

CAI=1

[81MD29H; 28586-PC]

Kogruk Formation Limestone with silicified zones containing crinoidal debris.

Fossil loc. 4 in Mayfield and others (1987).

163

NRA (Bogie

plate)

Noatak D-6

67°57'18"/

164°33'36"

Devonian-Permian

CAI=1

[81EK141]

Nuka Formation Sandy limestone.

Fossil loc. 2 in Mayfield and others (1987).

Late Mississippian-middle Middle Pennsylvanian (late

Meramecian-early Atokan)

CAI=1

[8-16-83J; 29233-PC]

Very light gray to pinkish-gray, terrigenous, fossiliferous grainstone

that contains plagioclase feldspar and quartz granules and sand.

Thin section is bioclastic grainstone with ≤7% rounded to

subangular noncarbonate detritus, mainly monocrystalline quartz

and lesser plagioclase and microcline feldspar. Bioclasts chiefly

crinoid ossicles and subordinate bryozoan and brachiopod

fragments. Trace amounts of phosphate and glauconite.

6.5 kg of rock was processed.

Sample collected by A.G. Harris.

Late Mississippian-middle Middle Pennsylvanian (late

Meramecian-early Atokan)

CAI=1

[8-16-83K; 29234-PC]

Grayish-red, terrigenous, arkosic wackestone with echinoderm

debris, plagioclase feldspar laths, and subrounded sand, granules,

and pebbles of quartz. Thin section is very poorly sorted, coarsegrained bioclastic grainstone with 10 to 15% chiefly rounded

noncarbonate detritus (monocrystalline and polycrystalline quartz,

plagioclase and microcline feldspar, and glauconite). Bioclasts

mainly crinoid and diverse bryozoan fragments. Minor

phosphate(?) and non-ferroan dolomite.

5.78 kg of rock was processed.

Sample collected by A.G. Harris.

164

PCA

Noatak D-6

67°53'36"/

164°55'48"

Early Mississippian-Permian

CAI=3

[81MD9E]

Kayak Shale Buff-weathering limestone between gray shale and black chert.

Fossil loc. 6 in Mayfield and others (1987).

165

NRA (Bogie

plate)

Noatak D-6

67°52'12"/

164°45'30"

Late Mississippian-middle Middle Pennsylvanian (late

Meramecian-early Atokan)*

CAI=2

[81MD57C; 38368-PC]

Nuka Formation Gray, very coarse grained, crinoidal limestone, adjacent to arkosic

limestone.

Fossil loc. 7 in Mayfield and others (1987).

166

KRA (Eli plate)

Noatak D-6

67°51'18"/

164°32'54"

early Early Mississippian (Kinderhookian)

CAI=1

[81EK149E; 28588-PC]

Utukok Formation Sandy limestone.

Conodonts indicate very shallow water environment.

Fossil loc. 3 in Mayfield and others (1987).

168 Noatak D-4

67°55'18"/

163°47'42"

early Late Devonian (early Frasnian)

CAI-2.5-3

[81EK152; 10461-SD]

Devonian carbonate rocks Silty, terrigenous limestone.
Table 13. Conodont samples from the Noatak quadrangle—Continued.

[All faunas identified by A.G. Harris. +Structural unit determined by L.E. Young. All other structural and stratigraphic units as reported by C.F. Mayfield and co-workers. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; NRA, Nuka

Ridge allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: EK, I. Ellersieck; MD, C.F. Mayfield; and TR, I.L. Tailleur. *, age revised by A.G. Harris in 2000. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Age of conodont fauna and CAI

[field No.; USGS collection No.]

Stratigraphic unit Remarks

169 Noatak D-4

67°52'48"/

163°39'48"

Late Devonian-Mississippian

CAI=2

[81EK2A]

Uncertain Black, limy shale and limestone turbidites(?)

170 Noatak D-3

67°57'24"/

163°24'00"

Late Devonian-Early Mississippian*

CAI=2.5

[81MD3]

Devonian carbonate rocks Limestone.

171

KRA

Noatak D-3

67°54’18"/

163°23’30"

Mississippian*

CAI=2.5

[81MD32A]

Lisburne Group

(Kogruk Formation?)

Limestone with minor black chert.

173

EMA

Noatak D-3

67°45'35"/

163°06'39.7"

Late Devonian-Early Mississippian

CAI=5

[81TR51]

Lisburne Group Black shale with minor limestone and chert.

174

EMA (Key

Creek plate)+

Noatak D-3

67°51'24"/

163°04'06"

early Early Mississippian (middle-late Kinderhookian)*

CAI=4-4.5

[81EK100A; 28587-PC]

Kayak Shale Fauna includes Bispathodus stabilis (Branson and Mehl)

1 Pa and 1 Sc elements [pl. 3, figs. 9, 10]

Sandy limestone.

Very shallow-water species association.

176

EMA

Noatak C-4

67°40'08.4"/

163°50'21.2"

Late Devonian (Famennian)-Late Mississippian (early Chester)

CAI=5

[81TR76C]

Lisburne Group

(Kuna Formation?)

Black, graphitic limestone.

179

EMA

Noatak C-4

67°34'42"/

163°54'30"

Early Mississippian

CAI=5

[81TR81F; 28369-PC]

Kayak Shale Limestone.

180

EMA?

Noatak C-3

67°32'48"/

163°23'30"

Late Devonian-Early Mississippian

CAI=5

[81MD49]

Devonian carbonate rocks Limestone from small outcrop surrounded by tundra.

181

EMA?

Noatak C-3

67°31'06"/

163°26'06"

Silurian-Triassic

CAI=5

[81EK105B]

Devonian carbonate rocks White limestone.

early Late Devonian (Frasnian)

CAI=4.5-5

[81EK105C; 10451-SD]

Devonian carbonate rocks Silty limestone interbedded with limy quartzite and phyllite.

Megafossils in this sample, identified by J.T. Dutro, Jr., include

molds and casts of the brachiopod Spinatrypa sp., thamnoporoid

corals, and the horn coral Macgeea sp.

These strata correlate lithologically and faunally with limestone of

the Nakolik River (map unit Dnl) of Karl and others (1989).

182

EMA

Noatak C-3

67°31'00"/

163°28'06"

late Middle-early early Late Devonian (Givetian-early Frasnian)

CAI=5-5.5

[SPL NO 93943; 10865-SD]

Devonian carbonate rocks Massive limestone from near top of thin carbonate unit that

conformably underlies the Hunt Fork Shale, basal unit of the

Endicott Group (Moore and others, 1986).

These strata correlate lithologically and faunally with limestone of

the Nakolik River (map unit Dnl) of Karl and others (1989).

4.1 kg of rock was processed.

Sample collected by D. Moore, I.L. Tailleur, and L.E. Young.
Table 13. Conodont samples from the Noatak quadrangle—Continued.

[All faunas identified by A.G. Harris. +Structural unit determined by L.E. Young. All other structural and stratigraphic units as reported by C.F. Mayfield and co-workers. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; NRA, Nuka

Ridge allochthon; PCA, Picnic Creek allochthon. CAI, conodont color alteration index. Letters in field number refer to collector: EK, I. Ellersieck; MD, C.F. Mayfield; and TR, I.L. Tailleur. *, age revised by A.G. Harris in 2000. Lithologic data under

remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Age of conodont fauna and CAI

[field No.; USGS collection No.]

Stratigraphic unit Remarks

183

EMA?

Noatak B-3

67°26'48"/

163°17'30"

Late Devonian-Early Mississippian*

CAI=5

[81MD46]

Devonian carbonate rocks Gray limestone.

184

NRA

Noatak C-1

67°35'12"/

162°17'00"

Silurian-Permian

CAI=4

[81EK208A]

Devonian carbonate rocks Brown-weathering, silty to sandy limestone.

185 Noatak C-1

67°35'30"/

162°05'18"

Silurian-Middle Devonian, likely Middle Devonian*

CAI=5-5.5

[81MD72D; 10494-SD]

Devonian carbonate rocks

(Baird Group?)

Dark-weathering dolomitic limestone with local black chert nodules.

186 Noatak B-1

67°25'00"/

162°05'00"

Late Silurian-Middle Devonian

CAI=5

[81MD83B; 10492-SD]

Devonian carbonate rocks

(Baird Group?)

Carbonate with black chert.

187 Noatak A-3

67°11'42"/

163°20'42"

Silurian-Triassic

CAI=4

[81MD67E]

Devonian carbonate rocks

(Baird Group?)

Partly metamorphosed limestone.

188 Noatak A-3

67°10'18"/

163°02'30"

Silurian-Permian

CAI=4.5

[81EK218B]

Devonian carbonate rocks

(Baird Group?)

Dark gray dolostone and limestone with chert nodules.

189 Noatak A-1

67°09'52.6"/

162°05'17"

Early Mississippian

CAI=5

[81TR179]

Kayak Shale Sandy to silty carbonate lens in Kayak Shale.

Heavy-mineral concentrate includes phosphatized gastropod

steinkerns.
Table 14. Radiolarian samples from the De Long Mountains quadrangle

[All faunas identified by C.D. Blome unless otherwise indicated. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector:

AD, J.A. Dumoulin; AK, J.S. Kelley; and JS, J.M. Schmidt. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or)

A.G. Harris unless otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Radiolarian fauna

[field No.; USGS collection No.]

Age Remarks

5

KRA (Wulik

Peaks plate)

De Long Mtns.

B-3

68°17'37"/

163°22'04"

One possible tumidaspine belonging to the Late Triassic

radiolarian family Capnuchosphaeridae DeWever (1979),

emend. Pessagno (1979), emend. Blome (1983)

[00AD4D; DR 2526]

?Late Triassic Sample from upper subunit of Siksikpuk Formation(?) (Etivluk

Group) overlying Kogruk Formation; see table 6 for conodont

sample from Kogruk at this locality. Triassic age is unlikely for

Siksikpuk.

Greenish-gray chert. Thin section shows locally well-preserved

radiolarians filled with microcrystalline quartz and (or) chalcedony

in matrix of cryptocrystalline to fine-crystalline chert with veins of

barite, a few phosphate(?) clasts, and minor dolomite.

Loc. 1 (fig. 2) of Dumoulin and others (2004).

Corum perfectum Blome

Muelleritortis cochleata cochleata (Nakaseko and Nishimura)

Pseudostylosphaera coccostyle (Rüst)

Pseudostylosphaera japonica (Nakaseko and Nishimura)

Pseudostylosphaera nazarovi (Kozur and Mostler)

Triassocampe sp.

[00AD4E; DR 2516]

Middle Triassic (middle to

late Ladinian).

Sample from middle subunit of Otuk Formation (Etivluk Group),

below recessive marker.

Gray chert. Thin section shows abundant, locally well-preserved

radiolarians in matrix of cryptocrystalline to fine-crystalline chert,

with veins of barite, scattered carbonate crystals, and rare

phosphatic bioclasts.

Capnuchosphaera sp.

Capnuchosphaera sp. aff. C. deweveri DeWever

Capnuchosphaera tricornis DeWever

Paleosaturnalis sp. (fragment)

Pseudostylosphaera helicatum (Nakaseko and Nishimura)

Pseudostylosphaera japonica (Nakaseko and Nishimura)

Abundant Pseudostylosphaera sp.

[00AD4F; DR 2517]

early Late Triassic (early to

middle Carnian)

Sample from middle(?) subunit of Otuk Formation, above recessive

marker.

Medium-gray and white chert; thin section shows abundant

radiolarians in matrix of cryptocrystalline to fine-crystalline chert,

with veins of barite, scattered carbonate crystals, and rare

phosphatic bioclasts.

33

PCA (Wulik

plate)

De Long Mtns.

B-2

68°24'45"/

162°37'21.5"

Bipedis acrostylus Bragin

Betraccium sp. aff. B. perilense Carter

Canutus? ingrahamensis Carter

Ferresium sp.

Pantanellium sp. aff. P. fosteri Pessagno and Blome

All forms very poorly preserved and coated with

manganese/iron stains.

[99AD1D; DR 2490]

Late Triassic (late Norian or

Rhaetian). The ranges of

these taxa indicate that the

fauna is assignable to either

the Betraccium deweveri

Zone (late Norian) of

Blome (1984) and Blome

and others (1988) or the

Proparvicingula

moniliformis and

Globolaxtorum tozeri Zones

(Rhaetian) of Carter (1993).

Probable upper subunit of Otuk Formation (Etivluk Group).

Dark-gray- to light-brown-weathering, grayish black siliceous

mudstone in fairly even, 5 to 8 cm thick beds. Thin section shows

abundant, locally well preserved radiolarians (tests have sharp

edges) and lesser thin "spicules" in a muddy matrix; radiolarian test

shapes fairly diverse.
Table 14. Radiolarian samples from the De Long Mountains quadrangle—Continued.

[All faunas identified by C.D. Blome unless otherwise indicated. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector:

AD, J.A. Dumoulin; AK, J.S. Kelley; and JS, J.M. Schmidt. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or)

A.G. Harris unless otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Radiolarian fauna

[field No.; USGS collection No.]

Age Remarks

35

PCA (Wulik

plate)

De Long Mtns.

B-2

68°21'56"

162°49'54.5"

Corum speciosum Blome

Corum regium Kozur and Mostler

Poulpus transitus Kozur and Mostler

Pseudostylosphaera japonica (Nakaseko and Nishimura)

Pseudostylosphaera sp.

All forms poorly preserved

[99AD19A; DR 2525]

early Late Triassic (Carnian,

probably early to middle,

although a few of the taxa

range into the upper

Carnian)

Sample from rubble of Etivluk Group (Otuk Formation?) directly

adjacent to black siliceous mudstone (uppermost Lisburne

Group?). Siksikpuk Formation appears to be missing here. See

table 4 for Lisburne conodont sample from this locality.

Medium-gray-green chert. Thin section shows scattered to abundant

radiolarians in matrix of cryptocrystalline to fine-crystalline chert;

radiolarians filled with fine-crystalline quartz (locally chalcedony);

some sharp test edges.

Eptingium sp. cf. E. manfredi Dumitrica

Triassocampe deweveri (Nakaseko and Nishimura)

Triassocampe sp.

Vinassaspongus erendili Tekin

Vinassaspongus subsphaericus Kozur and Mostler

[99AD19B; DR 2520]

late Middle Triassic (probably

middle to late Ladinian)

Subcrop of Etivluk Group (Otuk Formation) chert a few feet

southeast of 99AD19A.

Green chert. Thin section shows scattered to abundant radiolarians in

matrix of cryptocrystalline to fine-crystalline chert; radiolarians

filled with fine-crystalline quartz; many sharp test edges and some

preserved rim structure.

41

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°14'22"/

162°54'33.8"

Paleoxyphostylus variospina Won

Scharfenbergia tailleurense Holdsworth and Murchey

?Scharfenbergia ruestae (Ormiston and Lane)

No albaillellids found, despite lots of picking. Is there

something odd about this facies?

All forms poorly preserved

[98AD10B; DR 2452]

late Late Mississippian-early

Middle Pennsylvanian

(Chesterian to Morrowan).

Faunal group 2 of

Holdsworth and Murchey

(1988) and Assemblage

Zone 5 (Scharfenbergia

tailleurense assemblage) of

Murchey (1990).

Constraints from conodonts

at this locality restrict age

to early Chesterian.

Chert-rich upper part of Ikalukrok unit, Kuna Formation. Calcareous

radiolarite bed several meters below this sample was collected for

conodonts (98AD10A); see table 1 for conodont data from this

locality.

Black chert in even beds, 1 to 15 cm thick; faint millimeter-scale

color laminae. Thin section shows abundant, well preserved

radiolarians (sharp edges) in a muddy, cherty matrix. Most

radiolarians filled with chalcedony; a few with barite.

Loc. 3 (fig. 2) of Dumoulin and others (2004).
Table 14. Radiolarian samples from the De Long Mountains quadrangle—Continued.

[All faunas identified by C.D. Blome unless otherwise indicated. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector:

AD, J.A. Dumoulin; AK, J.S. Kelley; and JS, J.M. Schmidt. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or)

A.G. Harris unless otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Radiolarian fauna

[field No.; USGS collection No.]

Age Remarks

61

KRA (Wulik

Peaks plate)

De Long Mtns.

A-2

68°11'07"/

163°10'44.4"

Entactinia itsukaichiensis Sashida and Tonishi

Entactinia modesta Sashida and Tonishi

Follicucullus sp. aff. P. monacanthus Ishiga and Imoto

Latentifistula sp.

Nazarovella sp. (fragment)

Pseudoalbaillella sp. aff. P. longicornis Ishiga and Imoto

All forms poorly preserved

[98JS7A; DR2485 and 86]

late Early-middle Middle

Permian (middle

Leonardian-middle

Guadalupian).

Fauna assignable to

Pseudoalbaillella globosa

Zone of Ishiga (1986).

Sample from middle(?) subunit of Siksikpuk Formation (Etivluk

Group) overlying Kogruk Formation. Conodont sample 98JS7K,

taken from top of Kogruk slightly to southeast (loc. 62, table 6),

contained late Meramecian-Chesterian conodonts.

Maroon and light-greenish-gray shale and lesser chert. Thin section

consists of abundant radiolarians in a red muddy matrix.

This sample consisted of abundant maroon chert pieces and one large

gray chert piece. The maroon chert (DR 2485) was processed

separately from the gray chert (DR 2486). Preservation of

radiolarians was slightly better in the gray chert and this piece

provided most of the identifiable Permian radiolarians.

65

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°10'02.8''/

162°52'40"

Albaillella sp. aff. A. cartalla Ormiston and Lane (abundant

forms)

Albaillella sp. (same form that is shown in Holdsworth and

Murchey, 1986, pl. 34.1, number 7)

Pylentonema sp. cf. P. antiqua Deflandre (see fig. 6, nos. 22-23,

Blome, Reed, and Harris, 1998)

Scharfenbergia impella group (Ormiston and Lane)

Triaenosphaera hebes Won (partial test; entactinid with broad

spines)

All forms poorly preserved

[98AD7A; DR 2451]

early Late Mississippian

(Meramecian to lower part

of the Chesterian). Faunal

group 1B of Holdsworth

and Murchey (1988) and

Assemblage Zone 4

(Scharfenbergia impella gp

– Albaillella sp. aff. A.

cartalla assemblage ) of

Murchey (1990).

Ikalukrok unit of Kuna Formation; Suds prospect.

Dark gray to black chert; hillside rubble crop. Thin section shows

abundant radiolarians that appear well preserved (sharp rims) in a

muddy, cherty matrix.

66

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°10'18"/

162°50'48"

Betraccium sp.

Capnuchosphaera sp. aff. C. lenticulata Pessagno

Capnuchosphaera mexicana Pessagno

Capnuchosphaera schenki Blome

Capnuchosphaera smithorum Blome

Capnuchosphaera sp. aff. C. theoloides DeWever

Pseudoheliodiscus viejoensis Pessagno

Sarla vetusta Pessagno

[KE98-28; DR 2487]

Conodonts from this locality

indicate late Middle-Late

Triassic, but radiolarians

restrict age to middle Late

Triassic (late middle-early

late Norian).

Radiolarian fauna assignable

to the Betraccium Zone

(Pantanellium silberlingi

Subzone) of Pessagno and

others (1979) and Blome

and others (1988).

Sample from Otuk Formation (Etivluk Group); see table 9 for

conodont sample from this locality.

Chert interbedded with very fine grained dolostone. Carbonate

interbeds contain rare thin bivalve shells identified as Monotis(?)

sp. of Late Triassic age by R.B. Blodgett (Oregon State University,

unpublished fossil report, 1999) and yielded a single conodont.
Table 14. Radiolarian samples from the De Long Mountains quadrangle—Continued.

[All faunas identified by C.D. Blome unless otherwise indicated. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector:

AD, J.A. Dumoulin; AK, J.S. Kelley; and JS, J.M. Schmidt. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or)

A.G. Harris unless otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Radiolarian fauna

[field No.; USGS collection No.]

Age Remarks

72

EMA (Key

Creek plate)

De Long Mtns.

A-2

68°07'37.8"

162°49'15.6"

Belowea variabilis (Ormiston and Lane)

Scharfenbergia ruestae (Ormiston and Lane)

Scharfenbergia sp. (broken arms)

All radiolarians poorly preserved

[00AD20A; DR 2521]

Probably late Late

Mississippian to early

Middle Pennsylvanian

(probably ChesterianMorrowan)

Siksikpuk Formation (base of lower subunit) 0.5 m above Kuna

Formation, on southeast side of “Orange Creek.” Contact marked

by horizon of mammiform structures with 40 cm of vertical relief.

Sample from 10 cm thick bed of moderate orange weathering, dark

gray (locally slightly olive green) chert. Thin section shows

scattered radiolarians, most filled with chalcedony, in

cryptocrystalline chert matrix; test margins generally sharp and rim

structure locally well preserved.

Scharfenbergia concentrica (Rüst)

Scharfenbergia ruestae (Ormiston and Lane)

Scharfenbergia tailleurense Holdsworth and Murchey

Scharfenbergia sp.

No albaillelids found

All forms poorly preserved

[00AD20B; DR 2515]

late Late Mississippian to

early Middle Pennsylvanian

(Chesterian to Morrowan)

Upper Kuna Formation, just below contact with Siksikpuk

Formation. Upper Kuna here consists of ~8 m of chert above black

shale.

Medium-dark-gray to grayish black chert in 2 to 5 cm thick beds.

Thin section shows abundant radiolarians, filled with chalcedony

or polycrystalline quartz, in dark muddy matrix; test margins

generally sharp and rim structure locally well preserved; some

siliceous sponge spicules.

Belowea variabilis (Ormiston and Lane)

Scharfenbergia ruestae (Ormiston and Lane)

[00AD20C; DR 2524]

late Late Mississippian to

early Middle Pennsylvanian

(Chesterian to Morrowan)

Siksikpuk Formation, lower subunit, 0.5 m above 00AD20A.

Medium-gray to olive-gray chert, weathers moderate brown. Thin

section shows scattered to abundant radiolarians filled with

chalcedony or polycrystalline quartz; some fairly well-preserved

with sharp margins.

88

EMA

(Wolverine

Creek plate)

De Long Mtns.

A-2

68°01'12"/

162°45'00"

One cast of ?Albaillella sp.

Several poorly preserved spumellarians

[98AD18B; DR 2453]

Questionable Paleozoic Sample from section of unnamed deep-water facies of the Lisburne

Group underlying the Kogruk Formation on Anxiety Ridge.

Medium gray, fine-grained carbonate rock, in part replaced by(?)

black chert. Thin section is fine-grained carbonate (dolomite?) with

irregular zones of chert, relict peloids, and skeletal grains; bioclasts

include spicules and minor but well-preserved radiolarians (sharp

rims).

Loc. 22 (fig. 2) of Dumoulin and others (2004).

2 flattened poorly preserved casts of Albaillella sp.

[98AD18F; DR 2454]

Paleozoic (Devonian to

Middle Pennsylvanian).

Sample from section of unnamed deep-water facies of the Lisburne

Group underlying the Kogruk Formation on Anxiety Ridge, ~0.2

km south of sample 98AD18B.

Black mudstone rubble, weathers into dull, blocky slabs; interbeds of

brownish gray weathering, black fetid dolostone. Thin section is

partly silicified mudstone with locally abundant siliceous bioclasts

including radiolarians and spicules.

100

EMA (Key

Creek plate)

De Long Mtns.

B-1

68°19'00"/

162°16'35"

Poorly preserved casts of radiolarians (simple spheres)

[00AD14A; DR 2522]

Unknown Upper Kuna Formation, 20 cm below contact with the Siksikpuk

Formation; contact here marked by horizon of mammiform

structures with >5 cm of vertical relief.

Black chert in blocky 5- to 8-cm-thick beds. Thin section shows

abundant, locally very well preserved radiolarians (with rim

structure and sharp test margins) in dark muddy matrix.
Table 14. Radiolarian samples from the De Long Mountains quadrangle—Continued.

[All faunas identified by C.D. Blome unless otherwise indicated. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector:

AD, J.A. Dumoulin; AK, J.S. Kelley; and JS, J.M. Schmidt. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or)

A.G. Harris unless otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Radiolarian fauna

[field No.; USGS collection No.]

Age Remarks

107

EMA (Key

Creek plate)

De Long Mtns.

B-1

68°15'31.4"

162°13'20"

?Scharfenbergia ruestae (Ormiston and Lane)

Scharfenbergia tailleurense Holdsworth and Murchey

[97AK74B and E]

Radiolarians indicate an age

of, most likely, late Late

Mississippian to early

Middle Pennsylvanian

(Chesterian to Morrowan).

Conodonts from this locality

(97AK74F, ~40 ft above

base of section) indicate

that these strata are no

younger than early

Chesterian (see table 3).

Samples from Kuna Formation; part of 158-ft-thick measured section

of upper Kuna and lower Etivluk Group (Siksikpuk Formation).

We consider the contact between the two units to occur ~88 ft

above the base of the section, at the top of a horizon of

mammiform structures as much as 1 ft high. See table 3 for

conodont samples from this locality.

74B taken ~16 ft above base of section (72 ft below top of Kuna)

from medium-dark-gray to black chert in nodular beds 0.5 to 10 cm

thick with shale partings.

74E taken ~34 ft above base of section (54 ft below top of Kuna)

from similar chert in beds to 5 cm thick with black shale partings.

All faunas from this section identified by K. Reed (unpublished fossil

report, 1998).

Loc. 6 (app. 1) of Dumoulin and others (2004).

?Scharfenbergia ruestae (Ormiston and Lane)

 [97AK74D]

Sample ~26 ft above base of section and ~62 ft below top of Kuna

Formation.

Medium-dark-gray to black chert in nodular beds 0.5 to 10 cm thick

with shale partings.

?Scharfenbergia ruestae (Ormiston and Lane)

 [97AK74G and J]

late Late Mississippian to

early Middle Pennsylvanian

(Chesterian to Morrowan).

Samples from Kuna Formation, from medium-dark-gray to black

chert in nodular beds to 10 cm thick with black shale partings.

74G taken ~45 ft above base of section (43 ft below top of Kuna).

74J taken ~63 ft above base of section (25 ft below top of Kuna).

Glassy spheres (probable casts of spumellarians)

[97AK74H and I]

late Late Mississippian to

early Middle Pennsylvanian

(Chesterian to Morrowan),

based on age of underlying

and overlying samples.

Samples from Kuna Formation, from medium-dark-gray to black

chert in even beds 2 to 15 cm thick with black shale partings.

74H taken ~50 ft above base of section (38 ft below top of Kuna).

74I taken ~55 ft above base of section (33 ft below top of Kuna).

“late scharfenbergiid” form of Holdsworth and Murchey

[97AK74K and L]

late Late Mississippian to

early Middle Pennsylvanian

(Chesterian to Morrowan).

Samples from Kuna Formation, from medium-dark-gray to black

chert in beds 1 to 10 cm thick with shale partings.

74K taken ~65 ft above base of section (23 ft below top of Kuna).

74L taken ~73 ft above base of section (15 ft below top of Kuna).

Scharfenbergia tailleurense Holdsworth and Murchey

[97AK74M and X]

Samples from Kuna Formation.

74M taken ~78 ft above base of section (10 ft below top of Kuna)

from an interval of siliceous mudstone and ≤10% medium-darkgray to black chert in beds 0.5 to 3 cm thick.

74X taken ~83 ft above base of section (5 ft below top of Kuna) from

hard vitreous chert in beds 3 to 15 cm thick that form mammiform

structures as much as 1 ft high and 2 ft across.

?Scharfenbergia ruestae (Ormiston and Lane)

Scharfenbergia tailleurense Holdsworth and Murchey

late scharfenbergiid” form of Holdsworth and Murchey

[97AK74N]

Sample at top of Kuna Formation, ~88 ft above base of section and

just below contact with overlying Siksikpuk Formation.

Sample from interval of vitreous chert with mammiform structures.
Table 14. Radiolarian samples from the De Long Mountains quadrangle—Continued.

[All faunas identified by C.D. Blome unless otherwise indicated. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector:

AD, J.A. Dumoulin; AK, J.S. Kelley; and JS, J.M. Schmidt. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or)

A.G. Harris unless otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Radiolarian fauna

[field No.; USGS collection No.]

Age Remarks

107

EMA (Key

Creek plate)

[Cont.]

De Long Mtns.

B-1

68°15'31.4"

162°13'20"

?Scharfenbergia ruestae (Ormiston and Lane)

Scharfenbergia tailleurense Holdsworth and Murchey

[97AK74O]

late Late Mississippian to

early Middle Pennsylvanian

(Chesterian to Morrowan).

Sample from Siksikpuk Formation, ~93 ft above base of section and

5 ft above base of unit, from medium-dark-gray to black chert in

even to nodular beds 3 to 10 cm thick.

Scharfenbergia tailleurense Holdsworth and Murchey

[97AK74P]

Sample from Siksikpuk Formation, ~102 ft above base of section and

14 ft above base of unit, from medium-dark-gray to black chert in

even to nodular beds 3 to 10 cm thick .

Scharfenbergia tailleurense Holdsworth and Murchey

“late scharfenbergiid” form of Holdsworth and Murchey

[97AK74Q]

Sample from Siksikpuk Formation, ~108 ft above base of section and

20 ft above base of unit, from greenish-gray chert in beds 1 to 10

cm thick.

Glassy spheres (probable casts of spumellarians)

[97AK74R and S]

late Late Mississippian to

early Middle Pennsylvanian

(Chesterian to Morrowan),

based on age of underlying

and overlying samples.

Samples from Siksikpuk Formation, medium-gray to greenish-gray

chert in beds 1 to 5 cm thick.

74R taken ~113 ft above base of section (25 ft above base of unit).

74S taken ~118 ft above base of section (30 ft above base of unit).

Paroneaella? triporosa Holdsworth and Murchey

?Scharfenbergia ruestae (Ormiston and Lane)

Scharfenbergia tailleurense Holdsworth and Murchey

“late scharfenbergiid” form of Holdsworth and Murchey

[97AK74T]

Probably Early-early Middle

Pennsylvanian (Morrowan),

based on co-occurrence of

P.? triporosa and S.

tailleurense. P.? triporosa

in Alaska occurs with

conodonts of early

Morrowan age, and may

range into the early Atokan,

but the range of S.

tailleurense is most likely

Chesterian to Morrowan.

Sample from Siksikpuk Formation, ~153 ft above base of section and

65 ft above base of unit, from interbedded grayish-green chert

(beds 2 to 4 cm) and medium-grayish-green shale (beds 0.5 to 2

cm).

112 De Long Mtns.

A-1

68°11'44.8"

162°26'46.5"

Scharfenbergia tailleurense Holdsworth and Murchey

“late scharfenbergiid” form of Holdsworth and Murchey

[97AK40A]

late Late Mississippian to

early Middle Pennsylvanian

(Chesterian to Morrowan)

Kuna Formation, ~20 ft below contact with overlying Etivluk Group.

Contact marked by horizon of mammilary forms(?) ≤0.5 m across.

Dark-gray to black chert in blocky beds 5 to 20 cm thick, with

partings of black siliceous shale.

126

EMA

(Wolverine

Creek plate)

De Long Mtns.

A-2

68°09'20"

163°01'40"

Muelleritortis cochleata cochleata (Nakaseko and Nishimura)

Paronaella sp. aff. P. fragilis Kozur and Mostler

Pseudostylosphaera compacta (Nakaseko and Nishimura)

Pseudostylosphaera hellenica (DeWever)

Pseudostylosphaera japonica (Nakaseko and Nishimura)

Tritortis sp.

[DDH 927 (west of Anarraaq deposit), 1752 ft; DR 2519]

late Middle to early Late

Triassic (late Ladinian to

early Carnian)

Sample from middle subunit of Otuk Formation (Etivluk Group), 46

ft below contact with upper subunit, 20 ft below base of recessive

marker in middle subunit, and 37 ft above contact with lower

subunit.

Light to medium gray chert, locally greenish gray. Thin section

shows moderately well preserved, abundant radiolarians, some

with sharp margins; scattered dolomite rhombs.
Table 14. Radiolarian samples from the De Long Mountains quadrangle—Continued.

[All faunas identified by C.D. Blome unless otherwise indicated. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector:

AD, J.A. Dumoulin; AK, J.S. Kelley; and JS, J.M. Schmidt. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or)

A.G. Harris unless otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Radiolarian fauna

[field No.; USGS collection No.]

Age Remarks

131

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°09'46"

162°57'44"

Scharfenbergia sp. aff. S. tailleurense Holdsworth and Murchey

All radiolarians poorly preserved as casts only

[DDH 813 (Anarraaq deposit), 1771 ft; DR 2518]

Paleozoic Ikalukrok unit, 8 ft below contact with Siksikpuk Formation and 21 ft

above base of chert interval at top of unit. See table 1 for conodont

samples from this drill hole.

Dark-gray chert. Thin section shows moderate to abundant

radiolarians filled with fine-crystalline quartz or chalcedony in

dark muddy matrix; margins sharp and rim structure locally well

preserved.

136

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°06'14.4"/

162°50'29.8"

Albaillella sp. aff. A. furcata group Won (2 forms)

All forms very poorly preserved

[DDH 50 (north of Paalaaq deposit), 215 ft; DR 2457]

Late Mississippian-early

Middle Pennsylvanian

(Meramecian to

Morrowan).

Siksikpuk Formation, just above contact with black chert of the

Ikalukrok unit (Kuna Formation). The contact between the two

units may be faulted; breccia occurs along it.

Medium-light-gray (to light bluish gray) chert. Radiolarians notable

in hand sample, but thin section shows only a few round

radiolarian ghosts (some filled with barite).

Loc. 23 (fig. 2) of Dumoulin and others (2004).

Albaillella sp. aff. A. cartalla Ormiston and Lane

Paleoxyphostylus variospina Won

Scharfenbergia tailleurense Holdsworth and Murchey

Triactofenestrella sp.

[DDH 50, 219 ft; DR 2489]

late Late Mississippian-early

Middle Pennsylvanian

(Chesterian to Morrowan).

The concurrent ranges of

these four species indicate

that the fauna is assignable

to the Scharfenbergia

tailleurense assemblage

(Assemblage Zone 5) of

Murchey (1990).

Black chert of the Ikalukrok unit (Kuna Formation), about 4 ft below

contact with Siksikpuk Formation.

Grayish-black to black chert with notable radiolarians. Thin section

shows abundant, locally well preserved radiolarians (sharp edges)

in a muddy matrix; some tests filled with pyrite, others with barite,

but most with chalcedony.

150

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'23"/

162°50'3.7"

Albaillella sp. aff. A. furcata group Won

?Scharfenbergia sp. (one poorly preserved arm)

All radiolarians preserved as casts

[DDH 484 (Main deposit), 208 ft; DR 2458]

?Mississippian (questionable

Meramecian to Morrowan)

Shale and chert of Siksikpuk Formation; sample is about 12 ft above

an interval of pyritic barite that is ~8.5 ft thick and appears to be in

gradational contact with the chert.

Grayish-blue radiolarian chert interbedded with green mudstone;

sample from chert interval ~1 inch thick.

Sample collected by K.D. Kelley.
Table 14. Radiolarian samples from the De Long Mountains quadrangle—Continued.

[All faunas identified by C.D. Blome unless otherwise indicated. Structural units determined by L.E. Young. EMA, Endicott Mountains allochthon; KRA, Kelly River allochthon; PCA, Picnic Creek allochthon. Letters in field number refer to collector:

AD, J.A. Dumoulin; AK, J.S. Kelley; and JS, J.M. Schmidt. DDH, diamond drill hole. Interval thicknesses in drill holes are drilled thicknesses and have not been corrected for dip of bedding. All drill hole samples collected by J.A. Dumoulin and (or)

A.G. Harris unless otherwise indicated. Lithologic data under remarks are field descriptions unless otherwise indicated; thin section observations by J.A. Dumoulin. No., number; loc., locality]

Locality No.,

structural unit

Quadrangle,

latitude n./

longitude w.

Radiolarian fauna

[field No.; USGS collection No.]

Age Remarks

151

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'21.2"/

162°49'59"

Small poorly preserved radiolarian, probably internal spicules

Few casts of ?Albaillella sp.

All forms very poorly preserved

[DDH 24 (Main deposit), 126 ft; DR 2455]

?Paleozoic Ikalukrok unit (Kuna Formation).

Black chert with numerous fractures filled with silica and lesser

pyrite.

Sample collected by K.D. Kelley.

152

EMA (Red Dog

plate)

De Long Mtns.

A-2

68°04'17.5"/

162°49'47.8"

Capnuchosphaera sp. (isolated spines called “tumidaspines”)

Corum sp. aff. C. perfectum Blome

Corum sp.

Triassocampe sp.

All radiolarians poorly preserved and broken

[DDH 42 (Main deposit), 325 ft; DR 2456]

Late Triassic (late Carnian to

middle Norian). Fauna

assignable to the

Capnodoce Zone of Blome

(1984) and Blome and

others (1988).

Sample from ~10-ft-thick section of chert and shale logged as

Siksikpuk Formation; collected ~1 ft above ~15-ft-thick barite

interval. Radiolarian fauna indicates that unit sampled is the Otuk

Formation.

Dark-grey radiolarian chert interbedded with greenish shale. Chert

interval sampled cut by many silica-filled veins, including one

almost 0.5 inch wide.

Sample collected by K.D. Kelley.
Table 15. Conodonts illustrated in Plates 3 and 4 from the Howard Pass quadrangle

[All faunas identified by A.G. Harris. Structural units from Dumoulin and others (2004). CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; ADo, J.H. Dover, ARm, R.T. Miyaoka, and Tr, I.L.Tailleur. *,

species assignment revised after original publication. No., number; loc., locality]

Field and

USGS

collection Nos.

Quadrangle,

latitude n./

longitude w.

Stratigraphic and

structural units

Age and CAI of collection Conodont illustrated Reference, remarks

92AD35AA

32441-PC

Howard Pass

B-3

68°19'55"/

157°44'10"

Kuna Formation

(Lisburne Group)

Endicott Mountains

allochthon (Key

Creek plate)

late Early Mississippian; Upper G. typicus

Subzone or lower part Sc. anchoralis-Do.

latus Zone (early middle Osagean) on the

basis of age constraints from overlying

sample.

CAI=~3

Bispathodus utahensis Sandberg and

Gutschick [pl. 3, figs. 17-20]

*Gnathodus cuneiformis Mehl and Thomas

[pl. 3, fig. 21]

Dover and others (2004), table 1, loc. 147.

Collected at type locality of Kuna Formation (as

designated in Mull and others, 1982) from

small outcrop at stream level ~15 m west and

12 m topographically lower than base of

92AD35A measured section. If 92AD35AA

strata are in place, they are the lowest

exposure at the type locality.

92AD35C15.5m

32442-PC

Howard Pass

B-3

68°20'00"/

157°44'35"

Kuna Formation

(Lisburne Group)

Endicott Mountains

allochthon (Key

Creek plate)

late Early Mississippian; Sc. anchoralis-Do.

latus Zone (middle Osagean)

CAI=~3

Scaliognathus anchoralis Branson and

Mehl [pl. 3, fig. 25]

Dover and others (2004), table 1, loc. 146.

Collected from 15.5 m above base of ~68 mthick section of Kuna Formation at type

locality (as designated in Mull and others,

1982).

92AD55-22

32450-PC

Howard Pass

B-3

68°19'36"/

157°45'15"

Kayak Shale

(Endicott Group)

Endicott Mountains

allochthon (Key

Creek plate)

early Early Mississippian (Kinderhookian)

CAI=4

Bispathodus aculeatus plumulus Rhodes,

Austin, and Druce [pl. 3, figs. 11-12]

*Pseudopolygnathus nodomarginatus

(E.R. Branson) [pl. 3, figs. 13-14]

Dover and others (2004), table 4, loc. 148,

Dumoulin and Harris (1997), table 1, loc. 2.

About 1 km SW of type section of the Kuna

Formation; limestone and shale member of the

Kayak Shale, about 12 m below contact with

Rough Mountain Creek unit.

91ADo70C

31748-PC

Howard Pass

B-3

68°22'52"/

157°40'50"

Kayak Shale

(Endicott Group)

Endicott Mountains

allochthon (Key

Creek plate)

early Early Mississippian (middle to late

Kinderhookian)

CAI=~3

Bispathodus aculeatus plumulus Rhodes,

Austin, and Druce, nodosus morphotype

[pl. 3, fig. 16]

Dover and others (2004), table 4, loc. 143,

Dumoulin and Harris (1997), table 1, loc. 6,

and Mull and others (1997), table 1.

Limestone and shale member of the Kayak Shale

(Mull and others, 1997).

91AD6U

31742-PC

Howard Pass

C-3

68°32'00"/

157°34'55"

Rim Butte unit

(Lisburne Group)

Ipnavik River

allochthon

(Ipnavik plate)

No older than late Early Mississippian (no older

than middle Osagean).

 [1.5-2]

Bispathodus utahensis Sandberg and

Gutschick [pl. 3, fig. 15]

Dover and others (2004), table 4, loc. 54,

Dumoulin and others (1993), table 1, loc. 21.

From 67-meter-thick measured section within

Rim Butte unit, 61 m above base of section.

92ARm37B

32471-PC

Howard Pass

B-5

68°23'30"/

158°48'55"

Rim Butte unit

(Lisburne Group)

Ipnavik River

allochthon

(Ipnavik plate)

late Early Mississippian; Sc. anchoralis-Do.

latus Zone (middle Osagean).

CAI=3

Geniculatus claviger Hass, s.f. [pl. 3, figs.

22-23]

Dover and others (2004), table 1, loc. 91.

91Tr09B

31840-PC

Howard Pass

C-3

68°31.07'/

157°36.05'

Rim Butte unit

(Lisburne Group)

Ipnavik River

allochthon

(Ipnavik plate)

late Early Mississippian; lower half Sc.

anchoralis-Do. latus Zone (middle Osagean).

CAI=1.5-2

Doliognathus latus Branson and Mehl [pl.

4, figs. 3, 4]

*Geniculatus claviger Hass, s.f. [pl. 3, fig.

24]

Dover and others (2004), table 1, loc. 60.
Table 15. Conodonts illustrated in Plates 3 and 4 from the Howard Pass quadrangle

[All faunas identified by A.G. Harris. Structural units from Dumoulin and others (2004). CAI, conodont color alteration index. Letters in field number refer to collector: AD, J.A. Dumoulin; ADo, J.H. Dover, ARm, R.T. Miyaoka, and Tr, I.L.Tailleur. *,

species assignment revised after original publication. No., number; loc., locality]

Field and

USGS

collection Nos.

Quadrangle,

latitude n./

longitude w.

Stratigraphic and

structural units

Age and CAI of collection Conodont illustrated Reference, remarks

91Tr13

31841-PC

Howard Pass

C-3

68°31.1'/

157°35.5'

Rim Butte unit

(Lisburne Group)

Ipnavik River

allochthon

(Ipnavik plate)

late Early Mississippian; lower half Sc.

anchoralis-Do. latus Zone (middle Osagean).

CAI=~2 + heavy gray patina

*Gnathodus pseudosemiglaber Thompson

and Fellows [pl. 3, figs. 28, 30]

Protognathodus cordiformis Lane,

Sandberg and Ziegler [pl. 3, fig. 26]

*Pseudopolygnathus marginata (Branson

and Mehl) [pl. 3, fig. 27]

Dover and others (2004), table 1, loc. 59.

92AD20-14.5

32426-PC

Howard Pass

C-3

68°38'10"/

157°31'40"

Rim Butte unit

(Lisburne Group)

Ipnavik River

allochthon

(Ipnavik plate)

No older than late Early Mississippian; Sc.

anchoralis-Do. latus Zone (middle Osagean or

younger) with redeposited Famennian (late

Late Devonian) and middle-late

Kinderhookian conodonts.

CAI=1.5

Palmatolepis sp. of Famennian

morphotype redeposited during middle

Osagean or younger Mississippian time

[pl. 3, fig. 29]

Dover and others (2004), table 1, loc. 27.

Collected about 14.5 m below top of 42-m-thick

section of Rim Butte unit.

92AD214-18.5

32464-PC

Howard Pass

B-5

68°23'10"/

158°54'00"

Rim Butte unit

(Lisburne Group)

Ipnavik River

allochthon

(Ipnavik plate)

late Early Mississippian; Sc. anchoralis-Do.

latus Zone (middle Osagean).

CAI=2.5

Doliognathus latus Branson and Mehl [pl.

4, figs. 1, 2]

Dover and others (2004), table 1, loc. 89.

Collected from 18.5 m above base of ~85-mthick measured section of Rim Butte unit.

92AD214-44

32465-PC

Howard Pass

B-5

68°23'10"/

158°54'00"

Rim Butte unit

(Lisburne Group)

Ipnavik River

allochthon

(Ipnavik plate)

late Early Mississippian Sc. anchoralis-Do.

latus Zone (middle Osagean).

CAI=2.5-3

Mestognathus praebeckmanni Sandberg,

Johnson, Orchard, and von Bitter [pl. 4,

figs. 5, 6]

Dover and others (2004), table 1, loc. 89.

Collected from 44 m above base of ~85-m-thick

measured section of Rim Butte unit.

92AD50C

32447-PC

Howard Pass

C-5

68°44'45"/

158°55'35"

Rim Butte unit

(Lisburne Group)

Ipnavik River

allochthon

(Ipnavik plate)

No older than late Early Mississippian;Sc.

anchoralis-Do. latus Zone (middle Osagean)

with redeposited Kinderhookian and possibly

early Osagean conodonts

CAI=1.5-2

Gnathodus punctatus (Cooper), late

Kinderhookian-very early Osagean

species redeposited during middle

Osagean or younger Mississippian time

[pl. 4, fig. 7]

Dover and others (2004), table 1, loc. 2.

Collected ~15 m below top of ~50- to 60 m-thick

section of Rim Butte unit.
PLATE 1

Conodonts from the Kuna Formation and related deep-water facies of the Lisburne Group

(scanning electron micrographs; illustrated specimens are reposited in the U.S. National

Museum, USNM, Washington, D.C.; see tables 1-4 and maps 1 and 2 for conodont fauna,

age, biofacies, geologic setting, and location of collections listed below)

Kuna Formation, Ikalukrok unit (Red Dog plate, Endicott Mountains allochthon)

Figure 1. Gnathodus cuneiformis Mehl and Thomas, upper view of incomplete juvenile

Pa element, X100, DDH Su31, 1667-1686 ft., USGS colln. 29280-PC, USNM No.

530472 (map 2, loc. 123).

2-4. Gnathodus cuneiformis Mehl and Thomas, Protognathodus praedelicatus Lane,

Sandberg, and Ziegler, and Bispathodus utahensis Sandberg and Gutschick, 2 upper

and 1 outer lateral views of Pa elements, X100, DH 807, 1282-1297 ft., Gul subplate

of Red Dog plate, USGS colln. 33493-PC, USNM Nos. 530473-75 (map 2, loc. 128).

5, 6. Gnathodus texanus Roundy and Cavusgnathus unicornis Youngquist and Miller,

upper views of Pa elements, X100, field no. 99AD11BB, USGS colln. 33479-PC,

USNM Nos. 530476, 77 (map 1, loc. 76).

7. Gnathodus texanus Roundy, Pa element, upper view, X100, DDH Su16, 558-77 ft.,

USGS colln. 29279-PC, USNM No. 530478 (map 2, loc. 124).

8. Gnathodus sp., upper view of juvenile Pa element, X100, field no. KE98-19B, USGS

colln. 33644-PC, USNM No. 530479 (map 1, no. 48).

Kuna Formation, Kivalina unit (Red Dog plate, Endicott Mountains allochthon)
9, 10. Scaliognathus anchoralis Branson and Mehl, inner lateral view of incomplete Sa

element and lateral view of S element bar fragment, X100, DDH 640, 429-453 ft.,

Paalaaq deposit, USGS colln. 33488-PC, USNM Nos. 530480, 81 (map 2, no. 142).

Kuna Formation (Key Creek plate, Endicott Mountains allochthon)

11-13. Eotaphrus burlingtonensis Pierce and Langenheim, adult and juvenile Pa

elements, upper and lower views, X100, field no. 79MD44C, USGS colln. 27506-PC,

USNM Nos. 530482, 83 (map 1, no. 103).

14, 15. Polygnathus communis Branson and Mehl, Pa element, upper view, X180 and

Scaliognathus anchoralis, Sc element, inner lateral view, X150, field no. 00AD17H,

USGS colln. 33631-PC, USNM Nos. 530484, 85 (map 1, no. 103).

16, 17. Rhachistognathus prolixus Baesemann and Lane and Gnathodus texanus

Roundy, Pa elements, upper view, X100, field no. 97AK74F, USGS colln. 33404-PC,

USNM Nos. 530486, 87 (map 1, no. 107).

18, 19. Gnathodus cuneiformis Mehl and Thomas, juvenile and subadult Pa elements,

upper view, X100, field no. 79MD44C, USGS colln. 27506-PC, USNM Nos. 530488,

89 (map 1, no. 103).

Deep-water facies of the Lisburne Group (Picnic Creek allochthon)

20. Cavusgnathus regularis Youngquist and Miller, juvenile Pa element, outer lateral

view, X100, field no. KE98-24 (+590 ft.), Wulik plate, USGS colln. 33602-PC,

USNM No. 530490 (map 1, no. 34).

21, 22. Bispathodus utahensis Sandberg and Gutschick, outer and inner lateral views of

Pa elements, X100, field no. KE98-24 (+308 ft.), Wulik plate, USGS colln. 33600-

PC, USNM Nos. 530491, 92 (map 1, no. 34).
23-25. Rhachistognathus prolixus Baesemann and Lane, Gnathodus cuneiformis Mehl

and Thomas, and Gnathodus texanus Roundy, X100, field no. 99AD19D, Wulik

plate, USGS colln. 33481-PC, USNM Nos. 530493-95 (map 1, no. 35).

26. Cavusgnathus regularis Youngquist and Miller, Pa element, upper view, X80, field

no. 8-17-83B, Amaruk plate, USGS colln. 29236-PC, USNM No. 530496 (map 1, no.

20).

PLATE 2

Conodonts from deep-water facies of the Lisburne Group and from shallow-water facies

(Kogruk and Utukok Formations) of the Lisburne Group (scanning electron micrographs;

illustrated specimens are reposited in the U.S. National Museum, USNM, Washington,

D.C.; see tables 4-7 and maps 1 and 4 for conodont fauna, age, biofacies, geologic

setting, and location of collections listed below)

Deep-water facies of Lisburne Group (Picnic Creek allochthon) (continued)

Figures 1, 2. Hindeodus crassidentatus (Branson and Mehl), inner lateral and posterior

views of Sc and Sa elements, X100, field no. KE98-24 (+382 ft.), Wulik plate, USGS

colln. 33601-PC, USNM Nos. 530497, 98 (map 1, no. 34).

 3, 4. Vogelgnathus cf. V. pesaquidi Purnell and von Bitter, outer lateral views of juvenile

Pa elements, X150, field no. KE98-24 (+360 ft.), Wulik plate, USGS colln. 33643-

PC, USNM Nos. 530499, 530500 (map 1, no. 34).

 5, 6. Scaliognathus anchoralis Branson and Mehl, lateral views of S element bar

fragments, X100, field no. 00AD25F, Wulik plate, USGS colln. 33637-PC, USNM

Nos. 530501, 02 (map 1, no.117).
7-10. Eotaphrus burlingtonensis Pierce and Langenheim and Polygnathus communis

Branson and Mehl, upper and lower views of Pa elements, X100, field no.

79EK184B, Wulik plate, USGS colln. 27554-PC, USNM No. 530503, 04 (map 1,

no. 37).

Other deep-water strata of the Lisburne Group

11, 12. Geniculatus sp., upper and lower views of incomplete P element, X100, field no.

00AD26A, Nachralik Pass plate, Ipnavik River allochthon (IRA), USGS colln.

33638-PC, USNM 530505 (map 1, no. 120).

Kogruk Formation

13. Gnathodus homopunctatus Ziegler?, upper view, juvenile Pa element, X100, field no.

97AK51A, Kelly River allochthon (KRA), USGS colln. 33395-PC, USNM No.

530506 (map 1, no. 114).

14, 15. Polygnathus mehli Thompson, upper and lower views, Pa element, X100, field

no. KE98-25B, Wolverine Creek plate in Rok window, Endicott Mountains

allochthon, EMA, USGS colln. 33604-PC, USNM No. 530507 (map 1, no. 73).

Utukok Formation

16. Gnathodus cuneiformis Mehl and Thomas, upper view, juvenile Pa element, X100,

field no. 00AD15A, Utukok Formation, Kelly plate, KRA, USGS colln. 33630-PC,

USNM No. 530508 (map 1, no. 102).

17. Pseudopolygnathus sp., abraded subadult Pa element, upper view, X150, field no.

00AD6A, lower part of Utukok Formation, Key Creek plate, EMA, USGS colln.

33627-PC, USNM No. 530509 (map 1, no. 31).
18, 19. Siphonodella sp., juvenile Pa element, lower and upper views, X150, field no.

81EK69C, Eli plate, KRA, USGS colln. 28583-PC, USNM No. 530510 (map 4, no.

167).

20-26. Polygnathus bischoffi Rhodes, Austin, and Druce, Pa element, upper and lower

views, X100; Synclydognathus geminus (Hinde), Sb element, postero-lateral view,

X100; Pseudopolygnathus marginatus (Branson and Mehl)?, upper and lower views

of subadult Pa element, X150; and Pseudognathodus multistriatus Mehl and Thomas

(figs. 25 and 26), X100, field no. 79EK175C; olistolith probably derived from Picnic

Creek allochthon (PCA) or KRA, USGS colln. 27553-PC, USNM Nos. 530511-14

(map 1, no. 25).

27. Hindeodus crassidentatus (Branson and Mehl), outer lateral view of Pa element, X90,

field no. KE98-22, Wolverine Creek plate in Rok window, EMA, USGS colln.

33506-PC, USNM No. 530515 (map 1, no. 63).

28, 29. Hindeodus crassidentatus (Branson and Mehl) and Synclydognathus geminus

(Hinde), outer lateral views of Pa elements, X100, field no. 79CX119A,Wolverine

Creek plate in Rok window, EMA, USGS colln. 33348-PC, USNM Nos. 530516, 17

(map 1, no. 64).

PLATE 3

Conodonts from various units of the Lisburne Group and from the Kayak Shale of the

Endicott Group (scanning electron micrographs; illustrated specimens are reposited in the

U.S. National Museum, USNM, Washington, D.C.; see tables 7, 11, 13, and 15 and maps

1 and 4 for conodont fauna, age, biofacies, geologic setting, and location of collections

listed below)
Utukok Formation (continued)

Figures 1, 2. Pseudopolygnathus sp. and Bispathodus utahensis Sandberg and Gutschick,

upper view of juvenile and adult Pa elements, X150 and X100, respectively, field no.

97AK107A, Wulik Peaks plate, KRA, USGS colln. 33400-PC, USNM Nos. 530518,

19 (map 1, no. 52).

Kayak Shale, Endicott Group

3, 4. Polygnathus communis Branson and Mehl, upper and lower views of Pa element,

X100, field no. 81EK75F, Key Creek plate, EMA, USGS colln. 28584-PC, USNM

No. 530520 (map 4, no. 175).

5, 6. Synclydognathus geminus (Hinde), inner lateral views of incomplete Pb and Sa

elements, X100, field no. 81MD41E, EMA, USGS colln. 28367-PC, USNM Nos.

530521, 22 (map 4, no. 178).

7, 8. Patrognathus variabilis Rhodes, Austin, and Druce, upper and inner lateral views of

Pa element, X100, field no. 81EK75F, Key Creek plate, EMA, USGS colln. 28584-

PC, USNM No. 530523 (map 4, no. 175).

9, 10. Bispathodus stabilis (Branson and Mehl), outer and inner lateral views, Pa and Sc

elements, X100, field no. 81EK100A, Key Creek plate, EMA,USGS colln. 28587-PC,

USNM Nos. 530524, 25 (map 4, no. 174).

Howard Pass quadrangle

11-14. Bispathodus aculeatus plumulus Rhodes, Austin, and Druce, upper and outer

lateral views of Pa element, X100, and Pseudopolygnathus nodomarginatus (E.R.

Branson), upper and lower views of Pa element, X80, field no. 92AD55-22, from
limestone and shale member of the Kayak Shale ~12 m below contact with the Rough

Mountain Creek unit; USGS colln. 32450-PC, USNM Nos. 530526, 27.

15. Bispathodus utahensis Sandberg and Gutschick, outer lateral view of Pa element,

X80, field no. 91AD6U, Lisburne Group, Rim Butte unit, Ipnavik River allochthon,

USGS colln. 31742-PC, USNM No. 530528.

16. Bispathodus aculeatus plumulus Rhodes, Austin, and Druce, nodosus morphotype, Pa

element, upper lateral view, X80, field no. 91ADo70C, Kayak Shale, limestone and

shale member, USGS colln. 31748-PC, USNM No. 530529.

17-21. Bispathodus utahensis Sandberg and Gutschick, Sc, Sb, M, and Pb elements, 2

inner lateral, 1 postero-lateral, and 1 inner lateral views, X50, and Gnathodus

cuneiformis Mehl and Thomas, juvenile Pa element, upper view, X100, field no.

92AD35AA, Kuna Formation, USGS colln. 32441-PC, USNM Nos. 530530-34.

22-24. Geniculatus claviger Hass, s.f., Pb? elements. Figs. 22 and 23, upper and oblique

lower views of nearly complete element, X80, field no. 92ARM37B, Rim Butte unit,

Lisburne Group, Ipnavik River allochthon, USGS colln. 32471-PC, USNM No.

530535, and fig. 24, upper view of incomplete element, X75, field no. 91Tr09B, Rim

Butte unit, Lisburne Group, USGS colln. Ipnavik River allochthon, USGS colln.

31840-PC, USNM No. 530536.

25. Scaliognathus anchoralis Branson and Mehl, S element bar fragment, lateral view,

X100, field no. 92AD35C-15.5 m, type section of Kuna Formation, USGS colln.

32442-PC, USNM No. 530537.

26-28. Protognathodus cordiformis Lane, Sandberg and Ziegler, X100,

Pseudopolygnathus marginatus (Branson and Mehl), X80, and Gnathodus
pseudosemiglaber Thompson and Fellows, Pa elements,X100, upper views, field no.

91Tr13, Rim Butte unit, Lisburne Group, Ipnavik River allochthon, USGS colln.

31841-PC, USNM Nos. 530538-40.

29. Palmatolepis sp. of Famennian morphotype redeposited during middle Osagean or

younger Mississippian time, Pa element, upper view, X60, field no. 92AD20-14.5,

Rim Butte unit, Ipnavik River allochthon, USGS colln. 32426-PC, USNM No.

530541.

30. Gnathodus pseudosemiglaber Thompson and Fellows, Pa element, upper view, X80,

field no. 91Tr13, Rim Butte unit, Ipnavik River allochthon, USGS colln. 31841-PC,

USNM No. 530542.

PLATE 4

Conodonts from the Lisburne Group, Howard Pass quadrangle (scanning electron

micrographs; illustrated specimens are reposited in the U.S. National Museum, USNM,

Washington, D.C.; see table 15 for conodont age, geologic setting, and location of

collections listed below)

Howard Pass quadrangle (continued)

Figures 1-4. Doliognathus latus Branson and Mehl, P elements: figs. 1 and 2, upper

views of two poorly preserved, incomplete P elements, X80, field no. 92AD214-18.5,

Rim Butte unit, Lisburne Group, Ipnavik River allochthon, USGS colln. 32464-PC,

USNM Nos. 530542, 43; figs. 3 and 4, upper and lower views of relatively complete

P element, X75, field no. 91Tr09B, Rim Butte unit, Ipnavik River allochthon, USGS

colln. 31840-PC, USNM No. 530544.
5, 6. Mestognathus praebeckmanni Sandberg, Johnston, Orchard, and von Bitter, upper

and lower views of subadult Pa element, X100, field no. 92AD214-44, Rim Butte

unit, Lisburne Group, Ipnavik River allochthon, USGS colln. 32465-PC, USNM No.

530545.

7. Gnathodus punctatus (Cooper), Pa element, upper view, X80, field no. 92AD50C, late

Kinderhookian-very early Osagean species redeposited during middle Osagean or

younger Mississippian time, Rim Butte unit, Ipnavik River allochthon, USGS colln.

32447-PC, USNM No. 530546.