/BOO

Upper Devonian-Mississippian 

Stratigraphic Sequences in the 

Distal Antler Foreland of 

Western Utah and Adjoining Nevada

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Upper Devonian-Mississippian 

Stratigraphic Sequences in the 

Distal Antler Foreland of 

Western Utah and Adjoining Nevada

By N.J. Silberling, K.M. Nichols, D.L. Macke, and J6rg Trappe

EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN 

Harry E. Cook and Christopher J. Potter, Project Coordinators

U.S. GEOLOGICAL SURVEY BULLETIN 1988-H

A multidisciplinary approach to research studies of sedimentary 

rocks and their constituents and the evolution of 

sedimentary basins, both ancient and modern

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1995
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director

For sale by U.S. Geological Survey, Information Services

Box 25286, Federal Center

Denver, CO 80225

Any use of trade, product, or firm names in this publication is for descriptive purposes only and 

does not imply endorsement by the U.S. Government

Library of Congress Cataloging-in-Publication Data

Upper Devonian-Mississippian stratigraphic sequences in the distal Antler foreland 

of western Utah and adjoining Nevada / by N. J. Silberling ... [et al. ].

p. cm. (U.S. Geological Survey bulletin ; 1988-H) 

(Evolution of sedimentary basins Eastern Great Basin ; ch. H)

Includes bibliographical references.

Supt. of Docs. no.: 119.3 : B1988H

1. Geology, Stratigraphic Devonian. 2. Geology, Stratigraphic Mississippian. 

3. Geology Utah. 4. Geology Nevada.

I. Silberling, N. J. (Norman John), 1928- . II. Series. III. Series: Evolution of 

sedimentary basins Eastern Great Basin ; 

ch.H.

QE75.B9 no. 1988-H 

[QE665]

557.3 s-~dc20 94-46459 

[551.7'4'09792 CIP
CONTENTS

Abstract .......................................................................................................................... HI

Introduction.................................................................................................................... 2

Palinspastic Restoration ................................................................................................. 5

Upper Devonian-Mississippian Sequences ................................................................... 5

Procedure ............................................................................................................... 5

Langenheim Sequence ........................................................................................... 7

Gutschick Sequence ............................................................................................... 11

Morris Sequence .................................................................................................... 15

Sadlick Sequence ................................................................................................... 16

Maughan Sequence................................................................................................. 19

Discussion ...................................................................................................................... 21

References Cited ............................................................................................................ 22

Appendix Description of Lithosomes ......................................................................... 27

FIGURES

1. Map of Utah, Nevada, and adjacent States showing regional geologic features...................................................... H3

2. Map of western Utah and adjoining Nevada showing locations of significant Upper Devonian-Mississippian

stratigraphic sections and major faults...................................................................................................................... 4

3. Palinspastic map of study area.................................................................................................................................. 6

4. Chart showing positions of stratigraphic sequences and lithostratigraphic units..................................................... 7

5,6. Palinspastic cross sections of Upper Devonian-Mississippian lithosomes and sequences:

5. A^\............................................................_ 8

6. B-fi\................................................................................................................................................... 9

ill

Upper Devonian-Mississippian 

Stratigraphic Sequences in the

Distal Antler Foreland of 

Western Utah and Adjoining Nevada

ZtyNJ. Silberling, 1 K.M. Nichols, 1 D.L. Macke, 1 and Jorg Trappe

ABSTRACT

Upper Devonian to Mississippian strata in western Utah 

and adjoining Nevada were deposited in the distal 

(continentward) part of the Antler foreland. These strata are 

interpreted as five successive, second- and third-order stratigraphic sequences, informally named from oldest to 

youngest the Langenheim, Gutschick, Morris, Sadlick, and 

Maughan sequences. Each of these sequences records a 

major episode of transgressive-regressive deposition. Their 

depositional histories may be expected to reflect Antler 

tectonism at the continental margin, but the nature and 

timing of this protracted orogenic event is disputed, partly 

because palinspastic restoration of the subsequent, 

large-scale contraction and extension of the Antler orogen 

and its foreland is poorly known.

The Langenheim sequence of late Frasnian to 

mid-Famennian age records the initial open-marine 

mid-Paleozoic flooding of the inner shelf of the Cordilleran 

miogeocline. Transgressive ramp limestones of this 

sequence in westernmost Utah and adjoining Nevada are 

overlain by generally progradational, fine-grained, 

craton-derived, siliciclastic rocks of the Pilot Shale. These 

deposits represent a complex delta-lobe and prodelta clastic 

system, the first of this kind to be preserved on the Paleozoic 

shelf of the eastern Great Basin. The Gutschick sequence 

represents renewed marine transgression and regression 

during late Famennian to early Kinderhookian time that is 

recorded by the locally preserved upper part of the Pilot 

Shale and its lateral equivalents. The Pinyon Peak Limestone 

in west-central Utah is a separate expression of the 

Gutschick sequence, the accumulation of which was 

controlled by local tectonism.

1

80225.

2

U.S. Geological Survey, Denver Federal Center, Denver, Colorado

Institute of Geology, University of Bonn, Germany.

The overlying Morris sequence consists mainly of 

carbonate rocks of late Kinderhookian age, including much 

of the Fitch ville Formation in west-central Utah and the lower 

part of the Joana Limestone farther west. The lateral distribution and lithic character of the widespread Morris sequence 

resulted primarily from eustatic change rather than from local 

tectonism. The succeeding Sadlick sequence, of Osagean to 

Meramecian age, has at its base a thick, aggradational, lowstand systems tract represented by the Gardison Limestone. 

Tectonic subsidence that accommodated the intertidal to 

shallow-subtidal, tide- and storm-dominated carbonate 

deposits of this widespread formational unit was contemporaneous with uplift of the Wendover high farther offshore on 

the shelf. The sea-level maximum of the Sadlick sequence 

coincided with initiation of the Delle phosphatic event, initial 

deposits of which form the transgressive systems tract that 

onlaps both northwestward onto the evolving Wendover high 

and eastward onto the craton. Highstand strata of the Sadlick 

sequence include both fine-grained siliciclastic and carbonate rocks that reflect restricted, poorly oxygenated depositional environments, except for the uppermost, 

progradational strata of the sequence, which were deposited 

in high-energy environments near sea level.

The initial transgressive deposits of the subsequent 

Maughan sequence in Utah are characteristically 

rhythmically bedded limestones deposited below wave base 

during the late Meramecian. Above these is a mixed, 

highstand, clastic and carbonate depositional complex, 

including units such as the Humbug Formation and Great 

Blue Limestone. Farther west, restricted limestones and 

black shales form the lower part of the Maughan sequence, 

and they grade up into progradational normal-marine, 

bioclastic limestones.

The restricted-marine, siliciclastic deposits that form 

part of the highstand systems tracts of the Langenheim, 

Gutschick, and Sadlick sequences may have been retained 

on the shelf by subsidence continentward of foreland bulges 

resulting from flexural loading of the margin during 

successive episodes of AnUer orogenesis. The older of these

Hi
H2 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

hypothetical forebulges might be tectonically buried 

beneath Mesozoic thrusts of the Central Nevada thrust belt, 

if not by the Antler allochthon itself. The Wendover high, 

developed in concert with accumulation of the Sadlick 

sequence, may be the localized expression of mid-Mississippian forebulge development. The minor structural relief 

associated with such tectonism had a marked effect on the 

character and distribution of deposits of the distal Antler 

foreland; however, the boundaries of the sequences proposed by us in western Utah and adjoining Nevada correlate 

with those of the major eustatic sequences recognized by 

others. Thus, eustasy was the primary control on the major 

depositional sequences in the distal Antler foreland, and 

local tectonism only modulated the resulting pattern.

INTRODUCTION

Antler tectonism is generally thought to have resulted 

in the obduction of an allochthon of oceanic rocks onto the 

lower and middle Paleozoic miogeocline at the western 

margin of North America. Hypothetical plate tectonic 

mechanisms for emplacement of the Antler allochthon 

include arc-continent collision (Moores, 1970; Speed, 1983), 

collapse of a retroarc basin (Burchfiel and Davis, 1972,1975), 

and amagmatic, extension-coupled, "Mediterranean-type" 

orogenesis (B urchfiel and Royden, 1991). In western and central northern Nevada deformation of Cambrian to Upper 

Devonian sea-floor, rise, and slope deposits of the presumed 

Antler orogen was pre-Pennsylvanian, the age of unconformably overlying strata in these parts of Nevada (Roberts and 

others, 1958). Farther east, in east-central northern Nevada, 

this tectonism is commonly interpreted to have persisted from 

Late Devonian to Mississippian time (Johnson and Pendergast, 1981; Sandberg and others, 1982) and to have involved 

transport of the Antler allochthon on the Roberts Mountains 

thrust. In recent years, structural and subsurface studies of the 

Roberts Mountains thrust system have demonstrated deformation and thrust faulting that involves Mississippian rocks 

and predates deposition of Late Mississippian strata (Jansma, 

1988; Carpenter and others, 1993). Nevertheless, disagreement still exists regarding (1) the timing and kinematics of 

allochthon emplacement, (2) which rocks in central Nevada 

were allochthonous during Antler orogenesis, and (3) the significance of post-Paleozoic tectonic displacement of an original Antler-age allochthon (Ketner, 1983a, b; Speed and 

Sleep, 1983). In particular, determining which faults and 

other contractional structures observed in different mountain 

ranges of central Nevada relate to the Antler-age Roberts 

Mountains thrust system and which relate to the Central 

Nevada belt of Mesozoic thrusting (Taylor and others, 1993) 

has not yet been fully resolved (Ketner and Smith, 1982). To 

avoid the implication of a particular displacement history, the 

lower Paleozoic oceanic rocks that are allochthonous with 

respect to the miogeocline are thus referred to as the "Roberts

terrane" (Silberling and others, 1987); in the model of 

mid-Paleozoic overthrust emplacement, they are termed the 

"Antler allochthon."

Evidence that the Roberts terrane interacted 

tectonically with the Cordilleran Paleozoic margin is 

provided by nonmarine or shallow-marine coarse clastic 

deposits of Late Mississippian age in central and northern 

Nevada (the "Molasse" of Sadlick, 1960) that were derived 

from the Roberts terrane and shed eastward onto the 

continent. Orogenic foredeep deposits of earlier Mississippian age are recognized in a fairly narrow belt bordering the 

present-day eastern limit (fig. 1) of the Roberts terrane 

(Sadlick, 1960, 1965; Brew, 1971; Poole, 1974; Harbaugh 

and Dickinson, 1981; Trexler and Cashman, 1991); however, questions remain regarding the age, nature, and structural setting of these inferred foredeep rocks. Farther east on 

the shelf, the oldest sedimentologic indication of the 

possible encroachment of the Roberts terrane onto the continental margin is the abrupt appearance of open-marine 

limestone above a thick succession of inner shelf deposits of 

the miogeocline near the top of the Frasnian Stage in about 

mid-Late Devonian time. These open-marine limestones 

both underlie and intertongue with fine-grained siliciclastics 

of the Pilot Shale, which also first appear locally at about an 

age-equivalent level (Sandberg and others, 1989). Together, 

these Upper Devonian strata herald the advent of tectonic 

instability and the end of miogeoclinal deposition that had 

persisted since Late Proterozoic time.

Foreland effects of Antler orogenesis are thus recorded 

in strata of Famennian through Mississippian age in the 

region from the vicinity of the Roberts terrane in Nevada 

eastward into the Sevier thrust belt in Utah (fig. 1). This 

report describes the initial application in this region of 

depositional sequence analysis to these strata whose 

relationships are complicated structurally. Both the Roberts 

terrane in Nevada and the Antler foreland in eastern Nevada 

and western Utah have been significantly rearranged by 

tectonism that includes (1) middle and late Mesozoic 

thrusting of uncertain style and magnitude in the hinterland 

of the Sevier thrust belt (Bartley and Gleason, 1990; 

Thorman and others, 1991; Taylor and others, 1993); (2) 

poorly understood structural unroofing of thrust-thickened 

crust in late Mesozoic to early Tertiary time, at least in the 

north-central Great Basin (Wells and others, 1990; Hodges 

and others, 1992); and (3) Eocene to Miocene extension in 

poorly circumscribed domains in which the amount of 

extension may average as much as 100 percent and is interpreted for some domains to be as much as 300 percent 

(Cans, 1987).

In addition to the many palinspastic uncertainties 

resulting from this structural disruption, other factors also 

hinder sequence analysis in this region. Although Basin and 

Range physiography in the eastern Great Basin enhances 

surface exposure, it precludes continuity between outcrop 

areas. And, compared to other regions where depositional
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND

120° 110°

H3

IDAHO 

BATHOLITH

CENOZOIC COVER

xEastern limit of 

Roberts terrane

Eastern limit of other 

tectonostratigraphic terranes

Eastern limit of

Sevier thrust be t

SIERRA NEVADA 

BATHOLITH

40° -

36° -

EXPLANATION 

Cenozoic cover 

Mesozoic batholithic intrusive rocks

Lithotectonic terranes other than Roberts terrane 

and major terrane-bounding faults (solid lines 

within patterned areas)

Roberts terrane

Phanerozoic nonaccretionary North America

Figure 1. Map of Utah, Nevada, and adjacent States showing the location of figure 2 in relation to the eastern limit of the Roberts terrane, 

other accreted terranes and major terrane-bounding faults, the eastern limit of the Sevier thrust belt, and the initial strontium 0.706 isopleth 

(Elison and others, 1990).

sequence analysis has been successfully applied, subsurface 

information for the eastern Great Basin is relatively scarce. 

Instead, the history of local sea-level change must be 

interpreted primarily from surface exposures. For this, our 

strategy was to study the Upper Devonian to Upper 

Mississippian strata that represent the distal (continentward)

deposits of the Antler foreland in western Utah and 

adjoining parts of Nevada (fig. 2). In this part of the region 

Acknowledgments. The authors thank Tony Bryant, 

Steve Dorobek, Mitch Henry, Tom Judkins, Dave Miller, 

Joe Satterfield, and Jim Trexler for helpful suggestions on 

this and previous versions of the manuscript for this paper.
H4 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

115° 114° 113° 112° 111°

42=

41° 

40° 

39° -

~" 1 1 \ "^ 7~ii T1

Xi

i Leatham Hollow

r^ 1 Ol Old Lake Town

4 , Canyon

/ ' (Bear River Range) \ / 

/o \ °

Little Mountain , Q

Bishop Creek 

(Snake Mountains)

Porcupine Dam 

(Bear River Range

 ' -V ' ^ ') O Tripon Pass I / '-, i *

O (Windermere Hills) h PMot peak Sally Mountain Ogden ri <" x 

Northern | f (northern Lakeside Mountains) 4 " - > ft

Pequop MountainsO J^.-\r" /^ '.Q ~

 k*~" ! ' Silver / , ^ ^

f s

/ Q Island /

; / Southern

v' Crawford

O Mountains

i

^ 0

1 1

^

. __

| __ __

1 / Lakeside Mountains 

Leppy Hills (-) / ' Stansbury Island \ Becks Spur (Wasatch Range)^

Rosebud Canyon Q / /' """"^ L"lx x t

_;__?-r ^, m Sa\t Lake City ^,^,'

i

i

White Horse Pass -> -Q 

(Goshute Range) t

\

QCherry Creek Range

Antelope Range Q

Northern Red Hills Q

Southern Red Hills Q

« """ *" * *""""

/ Flux (northern " 0 

/ Stansbury Mountains) .- Samak (west end of 

^ . Umta Mountains)

/' "^ Ophir Canyon^ : ~ 

! ' i.i- . \ *(0quirrh *»'-. 

/ p Wig Mountain ^Mountains) <\ \

O Gold Hill \ . ^-^ i ' . p,

\ Mountain^ \ ' ^ (V

Northern Dugway \ Ratt | esnake Ridge -^~ 

fcRange0 ^ (East jintic district) ^\ ." ^^

X 'N X \ Fitchville Ridge ___ J ,.' ^

(bast untie district) / . ^s

4 / [^y

Gilson '

< Q Granite Mountain Mountains*'''!^"'" 

Q T ^ ^-*i

s

z

^ '" ^ '

3 Q Coyote Knolls o / \ ' i

1 i i Uelta n , ! .' \

Ward Mountain

/* n I ^

f )Confusion Range 5 \ ' ' \

QlEgan Range) | ) (/ ^

* i

\ |

/ ' O

Jjli: " /

m / v /

_j J^Burbank Hills - : / / /

\ 

\

\ '"" ^^ mi _/ > i > s'TS

<J rT, iU

1 1 * tjx Dog Valley (Pahvant Range) 

1 ' Needle Range x x

I Trough Spring Canyon ^ v>. x /

^.(southern Egan Range) /i ^ ^'

CY^^ * QDutch John Mounta 

Oside Hill Pass (southern

Schell Creek Range)

' \ * » n / /

8 / Star Range -\. 0 50 

f O .' i i

__-' /

\ iSK ,'~ Q Blawn Mountain

i ~> / (southern Wah Wan Mountains) i

EXPLANATION

_A__A_ Known or inferred thrust fault

Wasatch normal fault zone 

 Section at which lithosome SA. La. Pk is recognized

O Section at which stratigraphic level of lithosome SA. La. Pk is included,

*' A 

\

5ck Canyon

i/asatch Mountains) 

/ 

/ 

/

n >

t

_

100 KILOMETERS

I

I

lithosome is present
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H5

Figure 2 (facing page). Map of part of western Utah and 

adjoining eastern Nevada showing locations of significant Upper 

Devonian-Mississippian stratigraphic sections (open and solid 

circles). Numbers designate major faults: 1, Laketown thrust 

(Coogan and Royse, 1990); 2, Paris-Willard thrust; 3, 

Charleston-Nebo thrust; 4, East Tintic thrust (in part); 5, House 

Range detachment, interpreted as reactivated thrust (Villien, 1984; 

Royse, 1993); 6, Canyon Range thrust; 7, Pavant thrust; 8, Wah 

Wah thrust; 9, Wasatch fault zone. Structural features modified 

from Allmendinger and others (1983), Levy and Christie-Blick 

(1989), Miller (1990), Morris (1983), and others. Region west of 

Wasatch fault zone was technically extended a significant amount 

in Tertiary time; the highly extended belt of Cans and Miller (1983) 

is west of the shaded area, which represents the relatively 

undeformed House Range-Wah Wah structural plate, interpreted as 

the structurally highest plate of the Sevier thrust belt (Walker and 

Bartley, 1992).

the stratigraphic sections at northern Dugway Range, Gold 

Hill, Sally Mountain (northern Lakeside Mountains), and 

southern Lakeside Mountains (fig. 2) with the next closest 

locations farther to the west. North of the relatively coherent 

House Range-Wan Wah Mountains block, of which the 

sections at Needle Range, Burbank Hills, Confusion Range, 

Coyote Knolls, and Granite Mountain are a part, and west of 

the seismic and outcrop structural control that exists for the 

Wasatch Mountains, the Devonian-Mississippian sections 

on our reconstruction (fig. 3) were rearranged to provide the 

most reasonable paleogeography.

UPPER DEVONIAN-MISSISSIPPIAN 

SEQUENCES

PALINSPASTIC RESTORATION

In western Utah and adjoining Nevada significant 

stratigraphic sections of Frasnian to Chesterian age rocks are 

present at the places marked by circles in figure 2. Regional 

characterization of the depositional sequences requires 

rearranging these sections palinspastically, but the structural 

complexity of western Utah and adjoining Nevada and the 

isolated nature of exposures makes the palinspastic 

reconstruction shown in figure 3 problematical. Although 

reasonable estimates for Eocene and younger extension can 

be extrapolated from the analysis by Cans (1987) of the 

east-west strip between the 39th and 40th parallels, the 

correction for still earlier tectonism, especially that west of 

the Wasatch front, is subject to widely differing 

interpretations. Palinspastic reconstruction is partly dependent on understanding the pre-Tertiary facies themselves 

and the apparent tectonic juxtapositions among them, thus 

adding an inevitable element of circularity to structural 

interpretation.

Ignoring the possibility of significant pre-Eocene 

extension, the palinspastic correction incorporated in figure 

3 for the known or inferred Mesozoic contraction^ structures shown in figure 2 utilizes the analysis of the main 

Sevier thrust belt by Levy and Christie-Blick (1989) as a 

point of departure. In addition, we restored another 80 km of 

shortening to compensate for structurally higher Sevier 

thrusts, including the Wah Wah and Canyon Range thrusts 

(Walker and Bartley, 1992), that are thought to have large 

eastward transport (Friedrich and Bartley, 1992). Major 

thrusts of this level are also thought by us to include 

dismembered segments shown diagrammatically in figure 2 

such as the House Range detachment (reflection seismic 

events F and G of Allmendinger and others, 1983, on 

COCORP line 1) and hypothetical segments farther north 

such as those needed to explain the apparent juxtaposition of

PROCEDURE

Upper Frasnian to Chesterian strata comprising the 

sections shown in figure 2 are subdivided into 35 lithosomes. 

Each lithosome is a genetic unit that represents the rocks 

deposited in a distinct depositional environment or set of 

environments that existed for a particular area during a 

certain time. For each of the lithosomes a lithic description, 

an interpretation of depositional environment, and 

occurrence data are provided in the appendix. As further 

explained in the appendix, the descriptive names of the 

lithosomes are abbreviated in the text and figures by letter 

symbols. Each abbreviation consists of two or three parts, 

separated by periods, that represent, respectively, (1) the 

name of the sequence to which the lithosome belongs, (2) 

terms, if any, that modify the rock type, and (3) the rock type. 

For example, the lithosome forming part of the Sadlick 

sequence and characterized by laminated dolomitic siltstone 

is abbreviated SA.LaDo.St, and the lithosome of the 

Maughan sequence formed mainly of mudstone is 

abbreviated MA.Ms. Lists of the terms and their symbols 

adopted for modifiers and rock types are given in the 

appendix; many of the symbols are self-explanatory.

The depositional environments inferred for the various 

lithosomes and their lateral and superpositional relationships allow them to be interpreted, either individually or in 

groups, in terms of the systems tracts of stratigraphic 

sequences.3 Each of these sequences records a distinct 

transgressive-regressive cycle of deposition. The boundaries between sequences lie between the highstand systems 

tract of the preceding sequence and the lowstand systems 

tract, where present, or transgressive systems tract of the 

succeeding sequence. Certain boundaries between these 

sequences are more conspicuous regionally than others and

o

0 For an explanation of the concepts and terminology of sequence 

stratigraphy see, for example, Van Wagoner and others (1988).
H6 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

Old Lake Town Canyon

Eastern limit of lithosome

LA. La. St X -'

Leatham Hollow, 

Bear River Range J_

Western limit of lithosome 

GU. Be. Pk

Crawford Mountains

SA. La. Pk

Sally Mountain

=!t southern 

Lakeside Mountains 4.

j. Becks Spur 

T Stansbury Island

t

Samak

Rock Canyon, 

-j- Wasatch Mountains

/v

x Eastern limit of lithosome

GU. Be. Pk

Burbank Hills

Needle Range

Blawn Mountain -)-

100 KILOMETERS 

J

Figure 3. Palinspastic map showing selected locations from figure 2 in their structurally restored positions according to the constraints described in the text. Lines of cross sections A-A' (fig. 5) and B-B' (fig. 6) are also shown. Lithosomes LA.LaDo.St and 

GU.Bc.Pk are described in text and appendix. Light shading shows the extent of lithosome S A.La.Pk (in the lower part of the Sadlick 

sequence); dark shading indicates that part of the Wendover high in which the lower Sadlick sequence is abnormally thin or missing 

(and, locally, still older sequences are missing as well).

are utilized to divide the Frasnian to Chesterian section into 

five informally named second- or third-order stratigraphic 

sequences. To avoid the ambiguity inherent in designating 

sequences by numbers, letters, or the names of geographic 

features, these sequences are informally named, in 

ascending order, the Langenheim, Gutschick, Morris, 

Sadlick, and Maughan sequences in recognition of

individuals who have made important contributions to the 

knowledge of these strata4 (Silberling and others, 1993).

Significantly, Langenheim (1961); Gutschick and Rodriguez 

(1979); Morris and Levering (1961); Sadlick (1960, 1965); Maughan and 

Roberts (1967).
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPfflC SEQUENCES IN THE DISTAL ANTLER FORELAND H7

AGE

LATE 

SSISSIPPIAN

^

Z

< vRI LATE EARL 

Y DEVONIAN MISSISSIF

Chesterian

c

CD

Meramec

c

03 

CD 

O5

to

(/]

0

Famennian Kinderhookian

c

c 

<n

0}

ul

STRATIGRAPHIC 

SEQUENCE

MAUGHAN

SADLICK

MORRIS

GUTSCHICK

LANGENHEIM

WEST EAST 

WEST-CENTRAL UTAH AND ADJOINING NEVADA CENTRAL AND NORTH-CENTRAL UTAH

Willow Gap Member Manning Canyon Shale (part) 

of Chainman Shale

. . ... Great Blue Limestone Camp Canyon Member

of Chainman Shale

_. . . ,. n , Humbug Formation \ Uncle Joe Member Skunk Spring Limestone Bed - ^

of Chainman Shale ? Deseret Upper part of Tetro Member

/iv Limestone

Needle Siltstone Member of Woodman Formation 

Chainman Shale

\/ \x

/\

Gardison Limestone

>

Fitchville Formation / 

>

N' J

I

Leatham Member and upper member Leatham w j

of Pilot Shale Formation Pinyon Peak Limestone , 

 7p of Lindgren and Loughlin (1919) /

I Lower member of ' 

Lower member __ "Contact ledge" Pinyon Peak / 

of Pilot Shale ^\ unit of Beirdneau Limestone of /" 

sj \ West Range Formation of Sandbergand S 

+ Limestone Williams (1948) Poo\e(Wl).s' ' 'I

Guilmette Formation and equivalents |

f

Figure 4. Chart showing the positions of the stratigraphic sequences described in the text and their relationship to widely recognized 

lithostratigraphic units in western Utah and adjoining Nevada. Vertical ruling represents stratigraphic hiatus.

Some of these named sequences, such as the Morris, 

represent a single transgressive-regressive cycle of 

third-order scale, whereas others such as the Langenheim 

and Maughan are of second-order duration and at least 

locally incorporate within them distinct subsidiary 

transgressive-regressive cycles of third-order and lesser 

rank. As might be expected, the sequence boundaries lie 

within some of the established lithostratigraphic units in the 

region as shown in figure 4.

The relationships among these sequences and their 

component lithosomes are shown in figures 5 and 6, which 

are palinspastic cross sections trending at a high angle to the 

inferred depositional strike (fig. 3). Lithesome thicknesses 

on each of the cross sections are interpolated from those in 

the nearest measured sections on either side of the lines of 

cross section. The more northern cross section (fig. 5, line 

A-A') extends from the Leppy Hills on the Nevada-Utah 

border east-southeastward through West Mountain (fig. 3). 

Stratigraphic sections in the East Tintic district (fig. 2) lie 

just south of this line of cross section. The nature of the 

record at Samak at the west end of the Uinta Mountains (fig. 

2) on autochthonous North America is projected south 

into this line of section. The more southern cross section 

(fig. 6; line B-B') extends from Indian Creek in the 

east-central Cherry Creek Range in eastern Nevada

southeastward to the vicinity of Blawn Mountain at the south 

end of the Wah Wah Mountains and the Star Range in southwestern Utah (fig. 3). The seemingly rapid changes in stratal 

thickness on the cross sections (figs. 5, 6) result from the 

large vertical exaggeration; the steepest actual slopes in this 

reconstruction are barely one part in a thousand.

Most of the Upper Devonian to Mississippian strata at 

the locations plotted in figure 2 can be assigned to the lithosomes whose relationships are depicted in figures 5 and 6. 

Exceptions are the north westernmost locations Bishop 

Creek, Tripon Pass, northern Pequop Mountains, and Pilot 

Peak at which other lithosomes occur; the higher parts of 

the Maughan sequence in central Utah, which have not yet 

been adequately studied; and parts of a few other 

stratigraphic sections where rocks of uncertain age or structure are present, as discussed later.

The lower part of the Langenheim sequence, the oldest 

of the sequences discussed herein, records initial 

mid-Paleozoic open-marine flooding of the Devonian inner 

shelf as represented in the eastern Great Basin. 

Pre-Langenheim Devonian strata in western and central 

Utah are cyclic peritidal dolostone and quartz sandstone of
H8 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

Flux (northern Fitchville Ridge 

Gold Hill Stansbury Mountains) (East Tintic district)

Samak (west end of 

Uinta Mountains)

Alternative placement of ; .''. SA v9.z;Ss. -:. ^%^V-->';}

lower contact of MA ^i : 'i .' ' '. A: ;.-^^hC^N&'">1 \ SA?.Rh.LmWk v'^v ^>&v ? " '' ' ' ^^4^^>t^

 -: ." \:7^i^iS^^:.^^^^

9. : - SA.Qz.Ss: .-. V :\':7T^^^^.^^^G^

 . .

TYPE STANSBURY 

FORMATION

Figure 5. Palinspastic cross section A-A' of Upper Devonian-Mississippian lithosomes and sequences. Line of section shown in figure 3. 

Control for cross section projected into line of section from locations whose names are shown. Heavy lines are sequence boundaries for the 

Langenheim (LA), Gutschick (GU), Morris (MO), Sadlick (SA), and Maughan (MA) sequences; abbreviations for lithesome designations 

are described in the appendix. Datum is the initiation of the Delle phosphatic event (Silberling and Nichols, 1990,1991) within the Sadlick 

sequence. Gradation in density of dot pattern expresses change in water depth interpreted for the depositional environments, the greatest 

density representing the relatively deepest environments. All of the sequences are shallowing upward except for the Sadlick sequence, which 

deepens upward (shaded area) to the level of the Delle phosphatic event, above which it shallows upward. Crosshatching represents 

coarse-grained secondary dolomite of uncertain protolith.

the Guilmette Formation (Middle and Upper Devonian) and 

its lateral equivalents. Locally, and farther to the east, 

sequences younger than the Langenheim onlap and overstep 

these Devonian rocks and rest on similar kinds of inner shelf 

deposits as old as Cambrian.

The most complete expressions of the Langenheim 

sequence are restricted to westernmost Utah (at Leppy Hills, 

Granite Mountain, Confusion Range, Burbank Hills, and 

Needle Range, fig. 2) and locations farther west in adjoining 

Nevada (such as at Cherry Creek Range, northern Red Hills, 

and Side Hill Pass, fig. 2). At most of these locations the lower, 

transgressive part of the Langenheim sequence consists of 

thin-bedded, mottled to nodular, abundantly pelletal packstone and wackestone of lithesome LA.PtCr.Pk (figs. 5, 6,

Figure 6 (facing page). Palinspastic cross section B-B' of Upper 

Devonian-Mississippian lithosomes and sequences. Line of section 

shown in figure 3. Control for cross section projected into line of 

section from locations whose names are shown. Heavy lines are sequence boundaries for the Langenheim (LA), Gutschick (GU), 

Morris (MO), Sadlick (SA), and Maughan (MA) sequences; abbreviations for lithesome designations are described in the appendix. 

Datum is the initiation of the Delle phosphatic event (Silberling and 

Nichols, 1990, 1991) within the Sadlick sequence. Gradation in 

density of dot pattern expresses change in water depth interpreted 

for the depositional environments, the greatest density representing 

the relatively deepest environments. All of the sequences are shallowing upward except for the Sadlick sequence, which deepens upward (shaded area) to the level of the Delle phosphatic event, above 

which it shallows upward.
UPPER DEVONIAN-MISSISSIPPIAN STRATTGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H9

Cherry Creek 

Range

B

Red Hills

Confusion Burbank Needle 

Range Hills Range

Blawn 

Mountain

B'

... -.^i:/;/^

.' :^ .' . ' '.' ' "".' . "~P" I-i-^-_; " o

 . <L '.'.'.! ' *' »« A Or» I rv> '.'. '"' ' T"lIZ=r*. '. f

^r~^y. :MA.Sp.Lm .-.:.

\.Ms ..;:'. .:; .':' "'{^^^4^.:: ': '; ' .:']./.' :''' '.

;\\y .;:'.'. .'.' '.^T?5v2i:y ' '.' '. MA.Ms&Sp.Lm'

,:: ' ' /' y^'^^^^K^^^^V:-:-^:;^^

100 KILOMETERS
H10 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

appendix). This lithesome is characterized by open-marine 

bioclasts derived mainly from crinoids and shelly fossils. 

Lithesome LA.PtCr.Pk has been mapped as part of the 

Guilmette Formation in the Leppy Hills (Schneyer, 1990) and 

in the Confusion Range (Hintze and Best, 1987); in the Burbank Hills it is included in the Upper Devonian West Range 

Limestone (Sandberg and others, 1989).

In the Burbank Hills (fig. 2), lithosome LA.PtCr.Pk 

grades upward into lithosome LA.PtCs.Pk characterized by 

pellet-calcisphere packstone. These lithosomes are similar in 

bedding characteristics and in their abundance of pelletal 

allochems, but lithosome LA.PtCs.Pk has a bioclast 

assemblage mostly limited to calcispheres and ostracodes. 

These kinds of bioclasts are indicative of restricted, lagoonal 

depositional environments where they are present elsewhere 

in JJpper Devonian and Mississippian carbonate-shelf 

deposits (see, for example, Richards and Bergeron, 1992).

Fine-grained siliciclastic rocks of the lower member of 

the Pilot Shale, most of which belong to lithosome 

LA.LaDo.St (laminated dolomitic siltstone), are intercalated 

with and overlie the limestones of lithosomes LA.PtCr.Pk 

and LA.PtCs.Pk (figs. 5,6). Lithosome LA.LaDo.St, together 

with black mudstone and shale of lithosome LA.Ms, forms 

much of the Langenheim sequence from the Confusion 

Range (fig. 2) northward. Together they are a lateral facies 

of the limestones of lithosomes LA.PtCr.Pk and LA.PtCs.Pk 

and mostly supplant them from south to north (fig. 6). Strata 

of all four of these lithosomes, both siliciclastic and 

carbonate, range in age at one place or another from the latest 

Frasnian to the mid-Famennian according to Sandberg and 

others (1989, fig. 10).

A few isolated graded beds, generally 10-50 cm thick, 

of intraclastic and sandy limestone that exhibit 

Bouma-sequence internal layering are present within the 

lower part of the continuous sections of laminated, dolomitic 

siltstone of lithosome LA.LaDo.St in the Leppy Hills, 

Cherry Creek Range, and Confusion Range (fig. 2). Where a 

number of these isolated beds are present in succession, as in 

the Leppy Hills (Poole, 1974; Nichols and Silberling, 1993), 

they vary from one to another and range from Bouma-like 

TA or TAB beds, some having composite and coarsely intraclastic TA layers, to more complete TABCE beds. Because of 

their stratigraphic context, composite TA layers, and variability in Bouma-sequence layering, we regard these beds as 

primarily storm deposits or tempestites. Storm activity was 

probably responsible for the initial turbid suspension of the 

finer grained sediment that ultimately formed these deposits, 

and transport was probably due primarily to storm-generated 

combined flow rather than to turbidity-current gravity flow.

Another minor component of significance for interpreting the depositional history of the Langenheim sequence is 

the slump-folded and brecciated limestone intervals that are 

as thick as a few meters. A few of these intervals are 

intercalated in the ubiquitous laminated dolomitic siltstone of 

lithosome LA.LaDo.St in the Confusion and Cherry Creek

Ranges in westernmostUtah and eastern Nevada, respectively 

(fig. 2). These sedimentary breccias are monolithologic and 

in most cases can be traced laterally within about 10m through 

slump folds into coherent, nodular, thin-bedded limestones 

similar to those that form lithosomes LA.PtCr.Pk and 

LA.PtCs.Pk. Therefore, transport by gravity flow of these 

deposits as breccias was minimal. In the Confusion Range 

some of the slump-brecciated limestone units occupy channels cut into the plane-laminated siltstone. In some channels 

the partly brecciated limestone either laterally cuts into earlier 

channel deposits of sandstone or is scoured out by subsequent 

sandstone channel fillings, all within 2 m of stratigraphic 

thickness. Similar to the partly slumped and brecciated limestone units in the Confusion Range, those in the Cherry Creek 

Range have been treated by others as debris flows, with the 

implication of appreciable transport and association with 

slope environments and deep-water submarine fans (for 

example, Sandberg and others, 1989; Jones 1990). This interpretation is unlikely, however, because these partly brecciated 

limestones in the Cherry Creek Range that intercalate with 

lithosome LA.LaDo.St and those that overlie it and form the 

Indian Ranch Tongue of the Guilmette Formation (Sandberg 

and others, 1989) are of restricted-lagoonal origin. They are 

monotonous, pellet-calcisphere packstones in which shelly 

fossils are scarce and generally restricted to gastropods, and 

they are included in lithosome LA.PtCs.Pk in figure 6. This 

lithosome also forms the upper part of the West Range 

Limestone in its southeasternmost sections, such as that in the 

Burbank Hills (fig. 2).

As compared with the stratigraphic sections of the Pilot 

Shale at Granite Mountain and in the Confusion Range (fig. 

2), the intervening section at Coyote Knolls (fig. 2) differs in 

that slump folds are prevalent and conspicuous in two intervals 

within the lower 60 m of section (Gutschick and Rodriguez, 

1979). These pervasively slumped, fine-grained clastic parts 

of the Coyote Knolls section contain unusually abundant 

graded beds. Twelve directional, soft-sediment folds measured in the upper slumped interval yield a mean downslope 

direction (with regional bedding rotated to horizontal) of 253° 

and a resultant vector having a magnitude of 0.78. The stratigraphically lowest slump-folded Pilot sandstone bed in this 

succession is a scant 15 m conformably and gradationally 

above inner platform oncolitic and Amphipora-tearing limestone of the underlying Guilmette Formation. These rocks are 

thus near the base of the Langenheim sequence. We interpret 

this local, sandy, slump-folded sequence at Coyote Knolls as 

part of a small delta along the eastern limit of Pilot deposition 

that was related to bypass drainage from the east across the 

surface of the Guilmette supratidal-carbonate and sand-sea 

flat. For this deltaic interpretation, it is significant that the 

siliciclastic rocks of this unusual part of the Pilot are evidently 

a lateral facies of the lithosome LA.PtCr.Pk, the limestones 

that are mapped with the upper part of the Guilmette (Hose 

and Repenning, 1964) about 20 km farther south in the 

Confusion Range. A different interpretation was offered by
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND HI 1

Sandberg and others (1988), who invoke a bolide impact to 

explain the slump folds in the Coyote Knolls section.

Although the siliciclastic rocks of the Pilot are commonly 

regarded as deep-marine basinal deposits (for example, by 

Sandberg and others, 1989), we interpret them instead as representing a mostly restricted, but storm-influenced, 

shallow-marine system (appendix). The nature of the predominantly siliciclastic lithosomes LA.LaDo.St and LA.Ms 

reflects changes not only in the depth of water but also in sediment supply and degree of restriction of the water mass. Moreover, these strata may have been deposited concomitantly with 

local tectonic subsidence, and they incorporate minor retrogradational and progradational parasequence sets. Placing 

these lithosomes into a simple sequence-stratigraphic framework reflecting the history of sea-level change is therefore 

difficult. Nevertheless, we view these siliciclastic deposits as 

having been built out from the east in delta-lobe fashion and 

having prograded laterally in a complex way over the ramp 

limestones of lithosomes LA.PtCr.Pk and LA.PtCs.Pk. 

Viewed in this way, they generally represent progradation by 

the highstand systems tract of the Langenheim sequence. The 

slumped and brecciated channel limestone units reflect minor 

rises in relative sea level and subsidiary transgression of 

restricted, lagoonal carbonate deposition into this clastic 

system. An upward transition from laminated dolomitic 

siltstone to shoreface sandstones exhibiting herringbone 

cross-stratification is present in the uppermost part of 

lithesome LA.LaDo.St in the southernmost in the Burbank 

Hills (figs. 2, 6). This transition provides a clear expression 

of progradation at the top of the Langenheim sequence.

Representation of the Langenheim sequence east of the 

Granite Mountain to Needle Range outcrop belt in westernmost Utah (fig. 2) is problematic. Possible candidates are 

among the thin successions included by Sandberg and Poole 

(1977) in their "middle Famennian depositional complex." 

One of these is the limestone that forms the upper 10-15 m 

of the Beirdneau Formation (Upper Devonian) at Leatham 

Hollow (fig. 2) in the Bear River Range, northern Utah, and 

was informally termed the "contact ledge" by Williams 

(1948). This limestone may be part of the Langenheim 

sequence because it is similar to lithesome LA.PtCr.Pk in 

composition, being a peloidal, crinoidal packstone and 

wackestone. Moreover, the "contact ledge" limestone is 

separated from the overlying Upper Devonian basal 

siliciclastic beds of the Leatham Formation of the Gutschick 

sequence by a distinct disconformity (Gutschick and 

Rodriguez, 1979). The "contact ledge" is reported, however, 

by Sandberg and Poole (1977) to be slightly younger within 

the Famennian than any known part of the Langenheim 

sequence, and thus it conceivably could be the lowstand 

systems tract of the Gutschick sequence. Where exposed at 

Leatham Hollow, an attenuation fault at its base separates the 

"contact ledge" from inner shelf dolostone and quartzite of 

the Beirdneau Formation.

Another possible part of the Langenheim sequence in 

west-central and southwestern Utah is the characteristically 

light colored, megascopically unfossiliferous, desiccated 

peloidal grainstone of lithesome LA?.Dc.Gr (fig. 6, appendix). This lithosome does not exceed a few tens of meters in 

thickness and apparently has been differentially eroded 

beneath the Gutschick sequence. It crops out only at and near 

Blawn Mountain, in the Star Range, and locally within the 

East Tintic district (fig. 2). Erosion surfaces, accompanied 

by sedimentary breccia of peloid grainstone and (or) thin 

layers of fine-grained sandy limestone or calcareous 

sandstone, are present throughout all three of these known 

occurrences of lithosome LA?.Dc.Gr. Both the upper and 

lower contacts of this lithosome are abrupt and apparently 

disconformable where well exposed in scattered outcrops on 

the southeast face of Pinyon Peak in the East Tintic district 

(between Rattlesnake and Fitchville Ridges, fig. 2).

The formational nomenclature applied to lithosome 

LA?.Dc.Gr has had a tortuous history. Most recently, on the 

basis that the description by Morris and Lovering (1961) of 

the Pinyon Peak Limestone (Upper Devonian) in the East 

Tintic district could be construed to include rocks having the 

character of this lithosome, Sandberg and Poole (1977) 

treated this lithosome as the "lower member of the Pinyon 

Peak Limestone." The original description of the Pinyon 

Peak by Lindgren and Loughgren (1919), as well as the 

subsequent description by Morris and Lovering (1961), 

pertains, however, mostly to lithosome GU.Bc.Pk (figs. 5,6) 

which we regard as part of the Gutschick sequence. In our 

view the erosional remnants of lithosome LA?.Dc.Gr 

beneath the Gutschick sequence are inshore parts of a 

broader shelf-carbonate deposit. They may represent an 

eastern, more inshore facies of the limestones of lithosome 

LA.PtCs.Pk and thus are part of the Langenheim sequence. 

On the other hand, conodonts from the uppermost part of 

lithosome LA?.Dc.Gr in the Star Range are regarded by 

Sandberg and Dreesen (1984) as being just slightly older in 

the upper Famennian than those that are abundant and widespread in lithosome GU.Bc.Pk of the Gutschick sequence.

GUTSCHICK SEQUENCE

The lithosomes of the Gutschick sequence are different 

in separate parts of the study area, depending on the 

structural level of the exposures within the Sevier thrust belt. 

A palinspastically more eastern, and structurally lower, belt 

of Gutschick sequence exposures, extending from the 

Lakeside Mountains and Becks Spur southward to Blawn 

Mountain (fig. 3), comprises different lithosomes than those 

preserved in limited outcrops farther west in the Burbank 

Hills and Confusion Range and to the north in the Bear River 

Range, as at Leatham Hollow (figs. 2,3).
H12 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

The similarity of the uppermost Famennian and lower 

Kinderhookian Gutschick-sequence succession that forms 

the upper part of the Pilot Shale in the Confusion Range with 

that of the Leatham Formation in the Bear River Range, and 

the similarity of both of these successions with the 

Sappington Member of the Three Forks Formation (Upper 

Devonian and Lower Mississippian?) in southwestern 

Montana, has long been recognized. These sections are well 

described by Gutschick and Rodriguez (1979) who show that 

these disjunct occurrences represent remnants of a distinct 

depositional belt.

Silty black mudstone and shale of lithosome GU.Ms 

forms the lower part of the Gutschick sequence in the 

Burbank Hills, Confusion Range, and Bear River Range. A 

conspicuous disconformity and lag deposit (appendix) mark 

the base of lithosome GU.Ms. In the Confusion Range we 

include in this lithosome both the "black shale unit" 

(Guschick and Rodriguez, 1979) of the Leatham Member of 

the Pilot Shale and the immediately underlying shaly part of 

the lower member of the Pilot, making the total thickness of 

the lithosome here about 30 m. The conodonts on which the 

middle Famennian age of this shaly uppermost part of the 

lower member of the Pilot in the Confusion Range was 

determined are described as having been obtained from the 

stratigraphic level of the conodont-rich lag at its base 

(Sandberg and others, 1989). Thus these shaly strata, which 

form the uppermost part of the lower member of the Pilot in 

the Confusion Range and overlie the lag deposit, are not 

ncessarily as old as middle Famennian. Consequently, they 

are included by us in lithosome GU.Ms along with the 

overlying "black shale unit" (of Gutschick and Rodriguez, 

1979) of the Leatham Member (Sandberg and others, 1989). 

The top of lithosome GU.Ms is described by Gutschick and 

Rodriguez (1979) as a disconformity in both the Confusion 

Range and Leatham Hollow sections. We interpret this 

lithosome to be the product of low-energy, restricted-marine 

deposition and to be the transgressive systems tract of the 

Gutschick sequence.

Lithosome GU.St, which overlies lithosome GU.Ms, 

has at its base in the Confusion Range (fig. 6) a distinct lag 

deposit overlain by shaly beds containing fossils such as 

conchostracans that are indicative of a paralic environment 

(Gutschick and Rodriguez, 1979). Gradationally above this 

fossiliferous shale is several meters of impure, nodular, 

oncolitic limestone that in turn grades upward into the 

siltstone that forms the major share of lithosome GU.St 

(appendix). The siltstone is sparsely fossiliferous and 

calcareous and becomes increasingly dolomitic toward its 

top, forming the progradational highstand systems tract of 

the Gutschick sequence. The stratigraphic succession within 

lithosome GU.St at Leatham Hollow (fig. 2) is remarkably 

similar to that in the Confusion Range (Gutschick and 

Rodriguez, 1979). The stratigraphic position of lithosome 

GU.St is taken by lithosome GU.WkSt in the Burbank Hills 

(figs. 2, 3,6), which is much closer to the Confusion Range

than is Leatham Hollow. In its only exposure at Burbank 

Hills lithosome GU.WkSt is mainly subtidal, rhythmically 

interbedded wackestone and siltstone that becomes 

increasingly dolomitized upsection and grades into shoreface quartz sandstone at its top (appendix).

Conodonts of the Polygnathus styriacus Zone are 

reported by Sandberg and others (1980) from concretions in 

the "lower black shale" unit (of Gutschick and Rodriguez, 

1979) that forms the upper part of lithosome GU.Ms in the 

Confusion Range (fig. 2). Thus the upper part of lithosome 

GU.Ms is no older than late Famennian, even if these 

conodonts are reworked. A diverse brachiopod fauna 

(Mackenzie Gordon, in Hose, 1966) and corals (Duncan, 

1964) from the oncolitic limestone and the immediately 

overlying siltstone of lithosome GU.St have counterparts in 

the Louisiana Limestone, which was named for the basal unit 

of the original Kinderhook Group (Keyes, 1892) of the 

Mississippi Valley. Additionally, Sandberg and others 

(1980) reported the occurrence of lower Kinderhookian 

conodonts in a channel deposit in the siltstone of lithosome 

GU.St. A similar fauna! succession is also reported for the 

Gutschick sequence at Leatham Hollow (Sandberg and 

Poole, 1977; Gutschick and Rodriguez, 1979). Consequently, the parallel lithologic expressions of the Gutschick 

sequence in the Confusion Range and at Leatham Hollow, 

and probably also the expression of the Gutschick sequence 

in the Burbank Hills, are earliest Mississippian in age, at 

least in their upper parts, and their stratigraphically lowest 

parts are no older than latest Devonian.

In Utah, east of the belt represented by outcrops in the 

Bear River Range, Confusion Range, and Burbank Hills 

(figs. 2, 3), the Gutschick sequence is characterized by 

lithosome GU.Bc.Pk (figs. 5,6; appendix). This lithosome is 

the lithically distinctive unit recognized by us as the Pinyon 

Peak Limestone (or the "upper member" of the Pinyon Peak 

of Sandberg and Poole, 1977; see earlier discussion of 

lithosome LA?.Dc.Gr and the discussion in Silberling and 

Nichols, 1992, about their "unit 1"). Exposures of lithosome 

GU.Bc.Pk probably represent a structural level within the 

Sevier thrust system above the Pavant thrust but beneath the 

highest zone of Sevier thrusts that includes the Wah Wah, 

House Range, Canyon Range, and Paris-Willard thrust 

segments (fig. 2). Lithosome GU.Bc.Pk commonly 

represents the earliest record of open-marine flooding over 

Devonian and older, inner shelf dolostone and quartzite in 

west-central Utah (such as at Sally Mountain south to the 

Gilson Mountains, fig. 3), except at those few places where 

lithosome GU.Bc.Pk overlies limestones of lithosome 

LA?.Dc.Gr (such as at Pinyon Peak near Fitchville Ridge, 

fig. 3). The relatively thin expression of lithosome GU.Bc.Pk 

at Flux (fig. 2) in the northern Stansbury Mountains and at 

Stansbury Island (fig. 2), where it either overlies or interfingers with the uppermost part of the synorogenic Stansbury 

Formation (Upper Devonian), suggests that a positive area 

bordered the depositional site of lithosome GU.Bc.Pk. The
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND HI3

present-day geographic relationship of the sections in 

different mountain ranges at Flux and Stansbury Island to 

that in the southern Lakeside Mountains (fig. 2), where 

lithesome GU.Bc.Pk is about 50 m thick and the Stansbury 

Formation is not represented (Silberling and Nichols, 1992), 

would appear to place this positive area to the east of the 

southern Lakeside Mountains; however, regional stratigraphic considerations and paleocurrent directions for the 

Stansbury at Flux (Trexler, 1992) support palinspastic 

restoration of Flux and Stansbury Island to the west of the 

southern Lakeside Mountains (fig. 3), as suggested by the 

structural synthesis of the region by Tooker (1983). Thus we 

relate the sections at Flux and Stansbury Island to a broad 

positive area west of the depositional site of lithesome 

GU.Bc.Pk, but we acknowledge the lack of conclusive 

structural reasons for this viewpoint.

Lithosome GU.Bc.Pk is fairly homogeneous and 

distinctive in both appearance and composition. 

Anastomosing, yellow-brown weathering streaks and thin 

layers of argillaceous to silty limestone enclose nodules and 

thin lenses of fine-grained gray bioclastic packstone and 

wackestone in which small crinoid columnals are the only 

readily visible allochems. Unlike other thin-bedded impure 

packstones, such as those of lithesome LA.PtCr.Pk, pellets 

form only a small proportion of lithosome GU.Bc.Pk limestones. The consistent age assignment of lithosome 

GU.Bc.Pk to the late Famennian on the basis of conodonts of 

the Lower or Middle Palmatolepis expansa Zone (Sandberg 

and Dreesen, 1984; Sandberg and others, 1989; Stamm in 

Silberling and Nichols, 1992) is in agreement with the occurrence of the ammonoid Cyrtoclymenia from the unit at Becks 

Spur (fig. 2) (Petersen and Stokes, 1983).

At most locations the well-oxygenated, current-agitated, 

open-ramp, impure limestones of lithosome GU.Bc.Pk are 

separated from the limestones of the overlying Morris 

sequence by as much as a few tens of meters of more massive 

limestone or secondary dolostone that by definition includes 

the lowest part of the Fitchville Formation (Upper Devonian 

and Lower Mississippian). Some of these Fitchville limestones (such as GU.MaCr.Pk, fig. 5) progradationally overlie 

lithosome GU.Bc.Pk and thicken to the east or southeast. 

Others, however, such as the limestone in the southern Lakeside Mountains that was designated "unit 2" by Silberling and 

Nichols (1992, fig. 3) and that was originally treated as either 

the top of their "cycle I" or the base of their "cycle II," clearly 

overlie a disconformity and belong to the Morris sequence.

The massive, solution-compacted, crinoidal packstones 

and grainstones of lithosome GU.MaCr.Pk form most of the 

lower part of the type Fitchville Formation at Fitchville 

Ridge (fig. 2) (the lowermost 3 m of the formation, as 

originally defined, is part of lithosome GU.Bc.Pk). 

Lithosome GU.MaCr.Pk is among the lithosomes shown 

schematically in figure 5 as forming the highstand systems 

tract of the Gutschick sequence. Evidence for the late 

Famennian age of lithosome GU.MaCr.Pk (most of the

lower Fitchville Formation) and for its regional lateral and 

vertical gradation into lithosome GU.Bc.Pk (the Pinyon 

Peak Limestone) was initially summarized by Rigby and 

Clark (1962). The Devonian-Mississippian systemic boundary was placed by Sandberg and Poole (1977) on the basis of 

conodonts within massive or rudely layered, coarse 

grainstone near the top of lithosome GU.MaCr.Pk in the 

type Fitchville at Fitchville Ridge. No perceptible physical 

break is present at this level, although a distinct break in deposition and a 20-cm-thick bed of sandstone marks the top of 

lithosome GU.MaCr.Pk. Farther south, near Broad Canyon 

in the Gilson Range (fig. 2), the characteristic silty wisps 

within the Pinyon Peak Limestone, in the upper part of 

lithosome GU.Bc.Pk, become notably coarser grained, and 

beds of massive crinoidal grainstone are intercalated in the 

sand-streaked limestone, suggesting progradation of 

lithosome GU.Bc.Pk by shoal-water limestone representing 

lithosome GU.MaCr.Pk. The presence of lithosome 

GU.MaCr.Pk at this location is obscured, however, by 

normal faulting.

The relationship between the enigmatic, highly 

localized, coarse-clastic deposits of the Stansbury Formation 

in its type area in the northern Stansbury Mountains (fig. 2) 

and the Gutschick sequence is not clear. As much as 26 m of 

impure crinoidal limestone, having the distinctive lithic 

character and yielding the same age conodonts as lithosome 

GU.Bc.Pk, is present in the uppermost part of the typical 

Stansbury Formation (Rigby, 1958; Sandberg and 

Gutschick, 1978). Locally this distinctive limestone grades 

upward from coarse-grained sandy rocks continuous with 

the thick underlying section of the Stansbury, and it is 

overlain by as much as 12 m of gritty dolostone, dolomitic 

quartzite, and fine-grained secondary dolostone containing 

late Famennian conodonts and corals (Sandberg and 

Gutschick, 1978). The lithically unique type section of the 

Stansbury includes 450 m of coarse conglomerate and 

subordinate quartzite and intertidal-supratidal p-dolostone.5 

Just north of its type area in the Stansbury Range, the 

Stansbury Formation has within it an angular unconformity 

exhibiting about 20° of discordance (Trexler, 1992). 

Sedimentologic studies by Trexler show that the principal 

transport direction for the Stansbury conglomerate was to the 

northeast and that it was a submarine deposit derived from 

equivalents of the underlying formations, which range from 

Cambrian to Devonian in age. To the west of its type section 

in the northern Stansbury Mountains, the Stansbury pinches 

out completely within a few kilometers, and the Pinyon Peak 

oversteps the Stansbury and older formations, eventually 

resting directly on Cambrian rocks. Postdepositional

 'The term "p-dolostone" is used for "primary" or "penecontemporaneous" dense dolostone that locally exhibits microbial lamination or desiccation features (Nichols and Silberling, 1980; Silberling and Nichols, 

1992).
H14 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

faulting is not significantly involved in these rapid lateral 

changes in the stratigraphy (Cashman, 1992).

Conodonts recovered from secondary dolostones, 

which are either in the lowest part of the Stansbury (Trexler, 

1992) or in a Guilmette-like unit that may disconformably 

underlie it, have been interpreted as middle Frasnian in age 

(R.G. Stamm and A.G. Harris, U.S. Geological Survey, 

written commun., 1991). These relations require substantial 

uplift of the source area for the Stansbury at some time after 

the middle Frasnian. Within the vast expanse in the eastern 

Great Basin of laterally monotonous Devonian peritidal 

deposits such as the Guilmette, the compressional 

deformation responsible for this uplift would be totally 

unexpected were it not for the unique exposure of the type 

Stansbury in the northeastern Stansbury Mountains. These 

erogenic deposits of the Stansbury suggest that a positive 

area developed generally west of the depositional site of 

lithesome GU.Bc.Pk during Late Devonian time. These 

deposits also permit speculation that this uplift and the 

concomitant deposition of the type Stansbury might 

correlate with the disconformity between the parts of the 

Pilot Shale representing the Gutschick and the older Langenheim sequences. The location of the relatively thick section 

of the type Stansbury Formation is shown in figure 5; 

however, the Stansbury is not placed within the sequence 

framework because its geographic extent is so limited and 

because its temporal equivalency with either the Langenheim or Gutschick sequences presently cannot be demonstrated. Speculatively, it could be a lowstand systems tract of 

the Gutschick sequence whose accomodation space was 

strongly controlled by local tectonism. On the other hand, it 

could be entirely older than the sequences considered here 

and unconformably overlain by deposits of the Gutschick 

sequence.

Other strata assigned to the Stansbury Formation at 

Stansbury Island and at Becks Spur (fig. 2) are almost 

entirely composed of cross-stratified quartzite that probably 

represents a depositional system separate from that of the 

typical Stansbury near Flux (Trexler, 1992). These rocks are 

overlain by lithosome GU.Bc.Pk with no reported 

intercalation or intergradation with the quartzite. These 

quartzites can be regarded as part of the widespread 

Devonian inner shelf sabkha and sand-sea deposits over 

which lithosome GU.Bc.Pk transgressed eastward.

Palinspastically farther south and west, the occurrence 

of the Gutschick sequence is equivocal. Near the line of 

section A-A' at Wig Mountain and Gold Hill (fig. 3), strata 

that would be correlatives of the Gutschick sequence are 

apparently everywhere omitted from the stratigraphic 

succession owing to faulting. In the northern Dugway Range 

(figs. 2,3) limestones originally included in the lower part of 

the "Madison limestone equivalent" by Staatz and Carr 

(1964) yielded conodonts assigned by R.G. Stamm (U.S. 

Geological Survey, written commun., 1991) to the upper 

Famennian Polygnathus styriacus Zone (now generally

referred to as the Lower Palmatolepis expansa Zone). On 

this basis these limestones may be part of the Gutschick 

sequence, but they are lithically different from any of the 

other manifestations of this sequence in western Utah. These 

limestones are about 50 m thick, conformably overlie the 

Hanauer Formation, a thick succession of Devonian 

dolomitic quartzite and dolostone, and consist of 

burrow-mottled, thin-bedded, pellet-calcisphere packstone 

and interbedded storm deposits of massive intraclast 

grainstones whose intraclasts are derived from the associated 

packstones. Locally, these limestones are overlain by as 

much as 20 m of p-dolostone and cross-stratified quartzite 

beneath lithosome MO.Rh.Wk, which forms the base of the 

overlying Morris sequence. These supra-Hanauer, 

pre-Morris sequence rocks in the Dugway Range, which 

represent a transgressive-regressive depositional cycle, may 

be an inshore, western facies of lithosomes GU.Bc.Pk and 

GU.MaCr.Pk; however, were it not for the conodont-based 

age determination, they, along with the locally recognized 

Hanauer Formation, could be related to regionally widespread pre-Gutschick sequence units such as the Guilmette 

Formation.

Still farther west, the Gutschick sequence has been 

completely eroded, if it was ever present, on the Wendover 

high. For example, in the Leppy Hills (fig. 3) lithosome 

MO.Di.WkPk of the Morris sequence (fig. 5) rests depositionally on lithosome LA.LaDo.St of the Langenheim 

sequence (Nichols and Silberling, 1993); at White Horse 

Pass (fig. 3) lithosome S A.LaDo.St of the Sadlick sequence 

depositionally overlies a limestone unit that has yielded 

conodonts having contradictory ages (R.G. Stamm, U. S. 

Geological Survey, written commun., 1991), but which may 

be part of lithosome LA.PtCr.Pk, and at Granite Mountain 

(fig. 3) lithosome SA.LaDo.St rests on lithosome 

LA.LaDo.St.

The concept of a discrete Gutschick sequence may 

seem an oversimplification in view of its disparate and 

disjunct rock record, possible direct involvement with 

contemporaneous local orogenesis, and apparent age span 

across the Devonian-Mississippian boundary, the biostratigraphic resolution of which is fraught with semantic 

arguments. It is thus reassuring that the reported biostratigraphic succession is much the same for lithosomes 

GU.Bc.Pk and GU.MaCr.Pk in the East Tintic district at 

Fitchville Ridge (figs. 3,5) as it is for lithosomes GU.Ms and 

GU.St. farther west such as in the Confusion Range (fig. 6) 

(Morris and Lovering, 1961; Sandberg and Poole, 1977; 

Gutschick and Rodriguez, 1979; Sandberg and others, 1980). 

Although the former pair of lithosomes at Fitchville Ridge 

apparently describe a simple transgressive-regressive 

sequence expressed in carbonate rocks, interpretation in 

terms of local sea-level history of the latter lithosomes in the 

Confusion Range is more problematic.
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H15

MORRIS SEQUENCE

The Morris sequence is primarily composed of carbonate rocks, not only in western Utah but also in adjoining parts 

of Nevada, Idaho, and Wyoming. In western Utah and 

eastern Nevada its thickness is generally less than 100 m, 

commonly less than 50 m, and it represents a single, marine 

transgression and regression. Although broad-scale lateral 

changes are present within them, the carbonate rocks of the 

Morris sequence.are noticeably more laterally consistent 

than are the underlying, partly clastic, Upper Devonian to 

lowermost Mississippian strata. The very broad, flat, late 

Kinderhookian carbonate ramp recorded by the Morris 

sequence signifies a time of relative tectonic quiescence in 

the distal foreland.

The Morris sequence is exemplified in much of western 

Utah by the Fitchville Formation, all of which except the 

lower member as exposed in the East Tintic district (fig. 2) 

represents the Morris. Lithosomes of the Fitchville included 

in the sequence are, from oldest to youngest, MO.Rh.Wk, 

MO.PdCr.Gr, and MO.Dc.Lm (fig. 5). Initial flooding for 

the Morris sequence is represented by lithosome 

MO.Rh.Wk, except in the southern Lakeside Mountains (fig. 

2), where lithosome MO.Di.WkPk ("unit 2" of Silberling 

and Nichols, 1992, as discussed earlier) is recognized as 

being the lowermost deposit of the Morris sequence. Lithosome MO.Di.WkPk in the southern Lakeside Mountains is 

palinspastically projected into cross section A-A' (fig. 5) 

between Flux and Fitchville Ridge; it has a sharp, disconformable basal contact with the underlying Gutschick 

sequence and grades up into lithosome MO.Rh.Wk.

In the Lakeside Mountains, as at most locations, lithosome MO.Rh.Wk ("unit 3" of Silberling and Nichols, 1992) 

consists of thin to medium limestone beds separated by 

laterally persistent, but irregular, thin layers of secondary 

chert. Originally, before development of the silicified layers, 

this limestone was evenly bedded with fine-grained 

siliciclastic partings between beds, as, for example, in the 

East Tintic district at Fitchville Ridge (fig. 2). Most of the 

limestone beds that make up lithosome MO.Rh.Wk are 

wackestones having fine-grained, open-marine bioclasts, but 

some beds are more coarsely skeletal, graded packstones 

interpreted as storm deposits because of their stratigraphic 

context. This lithosome does not extend eastward of the 

Tintic thrust (fig. 2) or into southern Utah east of the Wah 

Wah thrust (fig. 2) and its equivalents. To the north at Little 

Mountain (fig. 2) the lithosome has the same character and 

consists of about 10 m of regularly bedded, chert-stringer 

limestone overlying Devonian p-dolostone interstratified 

with unfossiliferous secondary dolostone. In contrast, in the 

Bear River Range on the Paris-Willard thrust plate (fig. 2) 

and in the Crawford Mountains (fig. 2) the equivalent of 

lithosome MO.Rh.Wk is a much greater thickness of evenly 

bedded lime mudstone transitional to the Paine Member of

the Lower Mississippian Lodgepole Limestone (Elrick and 

Read, 1991).

Massive, cross-stratified, peloidal-crinoidal grainstone 

of lithosome MO.PdCr.Gr represents shoal deposits that 

prograded over the open-ramp, rhythmically bedded, 

storm-deposited limestone of lithosome MO.Rh.Wk in 

west-central Utah (fig. 5). The allochems of lithosome 

MO.PdCr.Gr are distinctive because they are mainly 

conspicuously micritized crinoid columnals and 

equivalent-size peloids. Some peloids may be completely 

micritized skeletal grains, whereas others are rounded 

intraclasts.

Unfossiliferous, desiccated lime mudstone of lithosome 

MO.Dc.Lm overlies lithosome MO.PdCr.Gr with only a few 

meters of transition and continues the progradational highstand tract of the Morris sequence. Regionally, much of 

lithosome MO.Dc.Lm is dense lime mudstone such as the 

"pink lithographic limestone" of the East Tintic district (fig. 

2) (Morris and Lovering, 1961). Fenestral fabrics and 

desiccated peloid grainstones also are present in lithosome 

MO.Dc.Lm, the top part of which is commonly characterized by microbial lamination or even spectacular 

stromatolites, as in the "curley limestone" bed (Proctor and 

Clark, 1956).

In sections such as those at West Mountain and in the 

Gilson Range (fig. 3), palinspastically inshore and to the 

south and east of the East Tintic district (fig. 2), p-dolostone 

of lithosome MO.Pr.Do interfingers with lithosome 

MO.Dc.Lm in units as thick as 3 m and is associated with 

pervasive eogenetic (Nichols and Silberling, 1980) 

secondary dolomitization of much or most of the underlying 

parts of the Fitchville Formation (fig. 5). Farther to the south, 

in the Star Range and southern Wah Wah Mountains (fig. 2), 

lithosome MO.Pr.Do forms nearly all of the Morris sequence 

(fig. 6). At Blawn Mountain in the southern Wah Wah 

Mountains massive crinoidal eogenetic secondary dolostone 

that may represent lithosome MO.PdCr.Gr is present at the 

base, and the stromatolitic "curley limestone" is present at 

the top.

Most of the lithosomes of the Morris sequence, as 

typified in the Fitchville Formation of west-central Utah, can 

be recognized across the eastern Great Basin. The succession 

of lithosomes permits recognition of the Morris sequence 

within the rocks constituting the lower and commonly major 

part of what is customarily referred to as the Joana 

Limestone (fig. 4) in westernmost central Utah in the 

Confusion Range, Burbank Hills, and Needle Range (figs. 2, 

6) and still farther to the west at Dutch John Mountain (fig. 

2), in the southern Egan Range (fig. 2), arid beyond in eastern 

Nevada. At these locations the distinctive inner ramp 

limestones of lithosome MO.Dc.Lm are underlain in turn by 

lithosome MO.PdCr.Gr, then some interstratified 

combination of lithosomes MO.Rh.Wk and MO.PdCr.Gr, 

and ultimately MO.Rh.Wk at the base. Lithosome 

MO.Rh.Wk forms the major share of the Morris sequence
H16 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

toward the northwest end of palinspastic cross section B-B' 

(fig. 3). In these more western sections, the basal part of the 

Lower Mississippian Joana Limestone is commonly 

composed of quartz sandstone as thick as a few meters. In 

places, such as in the Confusion Range, this sandstone has a 

sharp, scoured base and can be regarded as the lowstand 

systems tract of the Morris sequence; elsewhere, however, 

such as in the southern Burbank Hills, it is gradational downward into the Gutschick sequence and forms the top of its 

highstand tract

In general, the lateral variations in the Morris sequence 

reflect increasingly offshore deposition and progradation 

toward the northwest during the late Kinderhookian, but this 

pattern was interrupted by subsequent erosion during 

development in Osagean time of the Wendover high (of 

Sadlick, 1965), an area of minor positive relief (fig. 3). 

Location of this Early Mississippian positive area is recorded 

by widely scattered sections in which the Morris sequence is 

missing, as at Granite Mountain and White Horse Pass (fig. 

3), or only thin remnants of it are preserved, such as in the 

northern Dugway Range and Leppy Hill (fig. 3).

Locally within the northern Dugway Range about 3 

m of nodular to thin-bedded, impure, fossiliferous upper 

Kinderhookian (Biller, 1976; P.E. Isaacson, oral commun., 1992) limestone is gradationally overlain by no 

more than 10 m of massive intraclast-peloid grainstone. 

These two units apparently correspond, respectively, to 

lithosomes MO.Rh.Wk and MO.PdCr.Gr, the latter of 

which is disconformably overlain by lithesome 

SA.Di.WkPk limestone of the Sadlick sequence. The Morris sequence is no more than several meters thick in the 

Leppy Hills (fig. 3), at the western end of the cross section A-A' (fig. 5), and here yields late Kinderhookian conodont faunas (Newman, 1980; Nichols and Silberling, 

1993). Its base is a minor (?) attenuation fault, but it is 

disconformably overlain by lithesome SA.LaDo.St that 

expresses the initiation of the Delle phosphatic event 

within the Sadlick sequence. Most of the Morris sequence 

in the Leppy Hills is massive, diffusely interbedded, peloidal-crinoidal wackestone and packstone and winnowed 

grainstone resembling lithesome MO.Di.WkPk but at its 

base is as much as 2 m of nodular to evenly thin bedded, 

cherty, packstone-wackestone (lithosome MO.Rh.Wk?) 

and at its top is a bed of oncolitic bioclastic wackestone. 

This relatively thin expression of the Morris sequence, as 

preserved beneath the Sadlick sequence in the Leppy 

Hills, thus represents a single shallowing-upward cycle. It 

could be a sub-Sadlick-sequence erosional remnant that 

fortuitously preserves a single depositional cycle, or alternatively it may represent the original full thickness of the 

Morris sequence at this location. If the latter, it would 

indicate initiation of the Wendover high (see later; fig. 3) 

as a positive area during deposition of the Morris 

sequence.

SADLICK SEQUENCE

The lower part of the Sadlick sequence records the 

gradual, progressive tectonic subsidence of a broad area to 

the east and southeast of the Wendover high (fig. 3). Carbonate deposition on this subsiding area was entirely above 

wave base and almost kept pace with subsidence. The 

resulting aggradational to slightly retrogradational lower 

part of the Sadlick sequence was a tectonically controlled 

lowstand systems tract. It includes some or all of lithosomes 

SA.La.Pk, SA.Oo.Gr, SA.Cr.Gr, and SA.Di.WkPk 

(appendix, figs. 5, 6) that form the Gardison Limestone in 

west-central Utah, It also includes the upper part of the Joana 

Limestone in the westernmost part of southern Utah (in the 

Confusion Range, Burbank Hills, and Needle Range, fig. 2) 

and in eastern Nevada (as at Dutch John Mountain and 

Trough Spring Canyon in the southern Egan Range, fig. 2). 

The evenly bedded limestone containing graded tempestite 

beds (SA.Rh.Wk, fig. 6) in the upper part of the Joana 

Limestone represents the lower Sadlick sequence farther to 

the north in eastern Nevada at Ward Mountain and in the 

southern Red Hills (fig. 2). Still farther to the north in the 

Antelope and Cherry Creek Ranges (fig. 2) further study is 

needed to place the sequence boundary between the Morris 

and Sadlick sequences within the Joana because of 

inadequate exposure. Maximum flooding during deposition 

of the Sadlick sequence coincided with the transgression of 

areas that developed positive relief during early Sadlick 

time, the initiation of the Delle phosphatic event that was 

associated with an abrupt change to oxygen-deficient 

sedimentation, the onset of fine-grained terrigenous-clastic 

deposition, and the interruption of carbonate deposition 

(Sandberg and Gutschick, 1984; Nichols and Silberling, 

1990; Silberling and Nichols, 1991).

Carbonate rocks of lithosome SA.La.Pk form the major 

part of the lowstand systems tract of the Sadlick sequence. 

They are lithically distinctive (appendix), widespread (figs. 

2, 3), and locally exceed 100 m in thickness. As described 

and illustrated by Silberling and Nichols (1992) in the 

Lakeside Mountains (fig. 2), they are conspicuously 

laminated or quasilaminated, well-sorted, fine-grained, 

pellet-crinoid packstones having subordinate, discrete, 

tempestite interbeds of intraclastic, crinoidal, coralline, and 

shelly debris, among which large gastropod shells are common. This distinctive lithosome represents shallow-subtidal 

to perhaps intertidal, open-ramp deposition on a broad, 

gradually and evenly subsiding, carbonate flat that was 

swept by energetic tidal and storm currents. Oolitic grainstones (lithosome SA.Oo.Gr) commonly are present beneath 

the tidalites and tempestites of lithosome SA.La.Pk or else 

are intercalated in their lower part, separated from the 

stromatolitic inner platform limestones of lithesome 

MO.Dc.Lm at the top of the Morris sequence by as much as 

a few meters of nondescript, bedded, bioclastic wackestone. 

These lenticular ooid-shoal deposits thicken from sections in
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H17

west-central Utah to those farther to the southwest (fig. 6). In 

the southern Wah Wah Mountains (Blawn Mountain, fig. 2), 

beneath the Wah Wah thrust, they form most of the section 

equivalent to the Gardison Limestone. On the upper plate of 

the Wah Wah thrust-House Range detachment (shaded area 

in fig. 2) in the Confusion Range and Burbank Hills, massive 

oolitic grainstone units as much as 10 m in thickness are 

intercalated with subordinate, pelletal bioclastic wackestone 

units and aggregate as much as 35 m in total thickness. As 

observed by Goebel (1991a), each oolite unit forms the bulk 

of a minor shoaling-upward cycle. The highest oolitic 

grainstone units interfinger with the overlying laminated 

packstones of lithesome SA.La.Pk in the Needle Range (fig. 

2), and this association has been observed as far west as the 

southern Egan Range (fig. 2) in adjoining Nevada.

Crinoidal grainstones (lithosome SA.Cr.Gr), which 

commonly exhibit large-scale cross-stratification, are 

present in west-central Utah as intercalated units in the upper 

part of lithosome SA.La.Pk. and commonly separate it from 

the overlying limestone of lithosome SA.Di.WkPk, which 

forms the top of the Gardison Limestone and equivalents 

throughout western Utah. Lithosome SADi.WkPk is 

lithically variable and yet distinctive in consisting of diffuse, 

intergradational, and interstratified layers of varying thickness that are mostly composed of bioclastic wackestone or 

packstone, although subordinate layers and lenses of lime 

mudstone and winnowed crinoidal grainstone also are 

present. Open-marine bioclasts and megafossils are 

abundant, and large, irregularly shaped nodules and 

bedding-plane stringers of replacement chert are 

characteristic. These limestones of lithosome SA.Di.WkPk 

are believed to represent wave- and storm-influenced 

deposition in a deeper subtidal open-marine environment 

than the tidalites, tempestites, and intercalated oolitic or 

crinoidal shoal deposits of the underlying lithosomes. 

Because of this deepening trend, the stratigraphic 

partitioning of the oolitic and crinoidal grainstone units in 

the lower and upper parts of lithosome SA.La.Pk, 

respectively, is suggestive of a deeper, more offshore 

depositional setting for the crinoidal-grainstone shoals as 

compared to that for those dominated by ooids, a pattern 

characteristic of other mid-Paleozoic carbonate ramps (see 

Elrick and Read, 1991).

Maximum flooding and transgression of the Sadlick 

sequence in Utah, both eastward onto the craton and 

westward onto the Wendover high, coincided with onset of 

the Delle phosphatic event (Silberling and Nichols, 1990, 

1991). This event was marked by an abrupt change to 

oxygen-deficient conditions, cessation of normal-marine 

limestone deposition, and retention on all but the more 

eastern and southeastern parts of the shelf of fine-grained 

siliciclastic sediment of cratonic origin, all of which are 

ascribed to restriction of the shelf by emergence of the 

Wendover high (Silberling and Nichols, 1991). The effects 

of the Delle event are evident throughout the study area, and

the distinctive, commonly phosphatic rocks that relate to 

initiation of the event form the base of lithosomes 

SA.LaDo.St and SA.Os.Lm and of several different, 

formally named, Lower and Upper Mississippian rock units: 

the Deseret Limestone in west-central Utah, the Needle 

Siltstone Member of the Chainman Shale in westernmost 

Utah and adjoining Nevada, the Woodman Formation 

(originally proposed for rocks at Gold Hill, fig. 2), and the 

Brazer Dolomite (as in the Crawford Mountains and at 

Samak, fig. 2) in the western Uinta Mountains. The name 

"Delle Phosphatic Member," typically as a member of the 

Woodman Formation in the southern Lakeside Mountains 

(fig. 2), was proposed by Sandberg and Gutschick (1984) 

for the rocks affected by onset of the Delle event; however, 

this formal rock unit cannot be recognized away from its 

type area because there is no consistent way to define 

regionally its upper boundary (Nichols and others, 1992).

Sedimentologic interpretation of the anomalous rocks 

of the Delle event has been controversial (Sandberg and 

others, 1991), but it is important for an understanding of the 

systems tracts and depositional geometry of the Sadlick 

sequence. We interpret the onset of the Delle event as the 

expression of a regional change in water chemistry, coupled 

with continued flooding of the shelf, rather than as an 

episode of emergence and erosion. The disconformity and 

local hardground that marks initiation of the Delle event was 

the result of dissolution, submarine erosion, and replacement'of the underlying limestone, which in most places 

belongs to lithosome SA.Di.WkPk and contains conodonts 

of early Osagean age (Sandberg and Gutschick, 1984; R.G. 

Stamm and B.R. Wardlaw, U.S. Geological Survey, written 

commun., 1990-1991). Exceptionally, in the Leppy Hills 

(figs. 2,3, 5), the northwesternmost exposure of the Sadlick 

sequence, limestones immediately below the initial deposits 

of the Delle event belong to the still older Morris sequence 

(Nichols and Silberling, 1993). These limestones are 

markedly solution compacted and commonly silicified and 

contain phosphate either as pore fillings or as replacement 

peloids for as much as a meter below their top. Detrital 

concentrations of phosphatic grains of different types 

(ooids, peloids, ossicle replacements, and phosphatic fossils, such as conodonts) characteristically cap the highest 

coherent limestone or replacement chert beneath rocks of 

the Delle event and infill any cavities associated with hardgrounds as illustrated by Silberling and Nichols (1991).

The microfacies of the Delle phosphorites indicate a 

submarine depositional environment characterized by 

fluctuating anoxic and oxic conditions and temporary events 

of sediment reworking (Silberling and Nichols, 1991). This 

environment suggests a complex combination of processes 

resulting in termination of carbonate bioclast production, 

temporary stratification of the water mass to initiate 

phosphogenesis, partial replacement of calcareous sediment 

or limestone by phosphate, dissolution and erosion of 

carbonate and development of hardgrounds, chert
H18 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

replacement, and the subaqueous transport and concentration 

of insoluble phosphatic grains.

The onset of the Delle event is recorded at the base of 

lithosome SA.LaDo.St west and north of a line 

palinspastically (fig. 3) trending roughly from Old Lake 

Town Canyon south to Fitchville Ridge and southwest to the 

Needle Range. The predominant component of this lithosome 

is plane-laminated to slabby, secondarily dolomitic, siltstone 

and very fine grained sandstone. East of this line, onset of the 

Delle event marks the base of lithosome S A.Os.Lm, an ostracode lime mudstone in which ostracodes are commonly the 

only conspicuous, petrographically recognizable fossils, suggesting abnormal marine-water chemistry during its deposition. Individual, laterally persistent, but regionally 

discontinuous units of lithosome S A.Os.Lm, as thick as 10 m, 

are present farther to the west as intercalations at various 

levels within lithosome SA.LaDo.St, as indicated schematically in figure 5. Toward the east, for example, in the East 

Tintic district, Oquirrh Mountains at Ophir Canyon, and 

Gilson Mountains (fig. 2), dolomitic siltstone of lithosome 

SA.LaDo.St is supplanted laterally, probably with some 

intergradation, by rhythmically bedded, variably silty lime 

mudstone and wackestone of lithosome SA.Rh.LmWk (fig. 

5). Although generally unfossiliferous, one or more massive, 

commonly graded beds of crinoidal grainstone or packstone 

may be intercalated within the fine-grained limestones of 

lithosome SA.Rh.LmWk. These coarsely bioclastic beds are 

regarded by us as storm deposits because of their stratigraphic 

context, but they also have been interpreted as deep-marine 

debris flows (Sandberg and Gutschick, 1984; for example, 

the "crinoidal wackestone" bed near the top of their "lower 

carbonate unit" in their fig. 9, which shows their 

interpretation of the section at Ophir Canyon). In the farthest 

southeast section, at Dog Valley (fig. 2), 35 m of rhythmically 

bedded, sparsely cephalopod bearing, lime mudstone, 

regarded as part of lithosome SA.Rh.LmWk, has at its base 

the phosphatic rocks that mark the initiation of the Delle 

event, and neither lithosome SA.Os.Lm nor lithosome 

SA.LaDo.St is represented. The lime mudstone unit here is 

abruptly overlain by about 10 m of crinoidal limestone, the 

stratigraphically highest of which contains large-scale 

cross-stratification suggesting progradation by crinoid shoal 

deposits of lithosome SA.Cr.WkPk over lithosome 

SA.Rh.LmWk. In the Star Range and southern Wan Wan 

Range (fig. 3) our understanding of the upper part of the 

Sadlick sequence and its relationship to the Maughan 

sequence is inferential (fig. 6) because of poor exposure and 

inadequate structural control.

The thicker phosphatic successions of the Delle event 

are in a belt that in figure 3 palinspastically trends 

north-northeast and includes sections such as at Old Lake 

Town Canyon, southern Lakeside Mountains, Flux, Gilson 

Range, and Needle Range and those in the East Tintic district 

near Fitchville Ridge. The thickest of these sections is in the 

southern Lakeside Mountains where phosphorites and other

diagenetically unusual rocks indicative of multiple episodes 

of fluctuation between anoxic and suboxic to dysoxic 

deposition and diagenesis (Silberling and Nichols, 1991) are 

present at intervals through more than 30 m of section within 

lithosome SA.LaDo.St. Although multiple layers of detrital 

phosphorite are present in the thicker phosphatic sections in 

this belt, only at the base of these sections, at their contact 

with the pre-Delle event limestones, are concentrates of 

phosphatized bioclasts and conodonts present. The 

conodont-rich limestone reported by Sando and others 

(1976) 1 m above the base of the Brazer Dolomite at Warner 

Hollow (near location Crawford Mountains, figs. 2, 4), and 

interpreted by them as an interfingering of "starved-basin 

and shelf-carbonate fades," is a minor fault repeat of the 

underlying limestone of lithosome S ADi.WkPk and the thin 

crust of reworked, concentrated phosphatic grains that caps 

it.

In contrast to the belt in which phosphatic rocks of 

the Delle event range upward through a significant amount 

of section, sections to the east, as in the Crawford Mountains, and to the west in the area of the Wendover high 

(fig. 3), contain layered phosphate that is restricted to a 

single, commonly detrital, concentration whose stratigraphic position coincides with the initiation of the Delle 

event. Nevertheless, all of the rocks of lithosomes 

SA.LaDo.St, SA.Os.Lm and SA.Rh.LmWk show some 

evidence of continuing oxygen deficiency during their deposition. For example, scattered nodules of phosphate are 

characteristic of the dolomitized siltstone of lithosome 

SA.LaDo.St, and the pervasive secondary dolomite in this 

lithosome probably resulted from sulfate:reducing diagenetic conditions. The limestone of lithosomes SA.Os.Lm 

and SA.Rh.LmWk, which are laterally equivalent to, and 

partly intercalated with, lithosome SA.LaDo.St, is generally devoid of larger fossils, suggesting oxygen deficiency, 

or else contains fossils indicative of abnormal 

marine-water chemistry such as a relative profusion of 

ostracodes.

LithosomesSA.LaDo.St, SA.Os.Lm, andS A,Rh.LmWk 

formed below normal wave base as evidenced by the pervasive 

plane lamination of the first of these and the rhythmically well 

bedded nature of the latter two of these units. The widespread, 

aggradational character of the underlying carbonate succession of lithosomes SA.La.Pk through SADi.WkPk requires 

that the surface over which lithosomes SA.LaDo.St through 

SA.Rh.LmWk were deposited was essentially flat. Owing to 

severe stratification of the water column, only a few tens of 

meters of down warping, centered in the middle part of the belt 

characterized by the Delle event, is necessary to account for 

the thicker expressions there of intense diagenetic effects.

The interpretation by Sandberg and others (1991, p. 

411) that the rocks of the Delle event represent a 

deep-marine setting, bounded to the east by steep slopes, 

relies heavily on the pronounced facies difference between 

the obviously shelfal Brazer Dolomite in the Crawford
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H19

Mountains (fig. 2) and the section at Old Laketown Canyon (fig. 2). The section indicative of the Delle event in 

Old Laketown Canyon is structurally disrupted beyond 

objective measurement, but it is mainly an expression of 

lithesome SA.LaDo.St that must have been several tens of 

meters thick (Sandberg and Gutschick, 1978). Contrary to 

the assertion that "recent subsurface control has reduced 

the [original depositional] distance between [these sections] to only 12 km" (Sandberg and others, 1991, p. 411), 

the seismic interpretation of Coogan and Royse (1990, fig. 

18) indicates that the sections are on separate plates of the 

Old Laketown thrust system (which includes the Meade 

thrust). The pre-Tertiary section of the Old Laketown plate 

is sufficiently different from that of the structurally overridden plates, such as that including the Crawford Mountains sections, so as to require at least several tens of 

kilometers of juxtaposition between these sections, as 

expressed in figure 3. Palinspastically, the actual amount 

of slope would be very slight and water depths for the 

Delle event need not have been any greater than that necessary to temporarily maintain stratification of the water 

column.

Another indication that water depths during the Delle 

event were not extreme (on the order of hundreds of meters) 

is the relatively thin stratigraphic thickness that separates the 

characteristically plane laminated dolomitic siltstone and 

associated phosphatic strata of lithosome SA.LaDo.St from 

stratigraphically higher, shallow subtidal or intertidal sandstones of lithosome SA.Qz.Ss (fig. 5). At Flux (fig. 2), for 

example, less than 50 m of section mostly consisting of 

massive, calcareous sandstone separates strata of lithosome 

SA.LaDo.St, the deposition of which was strongly influenced 

by the Delle event (Sandberg and Gutschick, 1978; Nichols 

and others, 1992), from sandstones within lithosome 

SA.Qz.Ss having the characteristic features of beach and bar 

deposits. These sandstones are medium to coarse grained and 

calcareous, contain both quartz and crinoidal-bioclast grains, 

and are distinguished by either crude planar lamination or 

large-scale, shallow trough cross-stratification; they form the 

upper part of the lowest of three shallowing-upward cycles 

shown in figure 5 as being within lithosome SA.Qz.Ss at this 

location. In each of these three cycles, sandstones of lithosome SA.Qz.Ss are overlain by limestones of lithosomes 

SA.Rh.LmWk or MA.Rh.LmWk whose sharp basal contacts 

represent successive flooding events. In the absence of biostratigraphic control at this level in the section at Flux, and in 

the absence of further stratigraphic control from nearby 

locations, an alternative to the placement of the 

Sadlick-Maughan sequence boundary shown in figure 5 

would be to designate the base of the Maughan sequence as 

coincident with the base of the lower of the two units of lithosome SA.Rh.LmWk at Flux, which are shown as being discontinuous in figure 5. The total thickness of the highstand 

systems tract of the Sadlick sequence could thus be even 

thinner than implied by this figure. Continuity of this

alternative placement of the sequence boundary cannot, however, be established at present.

Relatively small stratigraphic thicknesses are also 

characteristic of other shallowing-upward progressions that 

represent the highstand systems tract of the Sadlick 

sequence. For example, at Dog Valley (fig. 2) progradational crinoidal grainstone shoal deposits, interpreted as a 

tongue of lithosome SA.Cr.WkPk into SA.Rh.LmWk, are 

only about 50 m stratigraphically above phosphatic rocks of 

the Delle event at the base of lithosome SA.Rh.LmWk.

The most inshore expression of the highstand part of 

the Sadlick sequence is projected into the southeast end of 

the line of section depicted in figure 5 from Samak (fig. 2) at 

the west end of the Uinta Mountains. Here, ostracode-rich 

lime mudstone of lithosome SA.Os.Lm is overlain by 

fine-grained, rhythmically layered, spiculitic packstone 

assignable to lithosome SA.Rh.LmWk, which is overlain in 

turn by open-marine, well-agitated ramp and inner ramp 

shoal limestone of lithosome SA.Cr.WkPk that is partly 

secondarily dolomitized. Then, completing the upward, 

progradational succession is lithosome SA.Pr.Ds composed 

of peritidal cycles of p-dolostone and eogenetic secondary 

dolostone along with units of evaporite-collapse breccia 

(Nichols and Silberling, 1991).

Sections having relatively thick expressions of lithosome SA.LaDo.St, such as those in the Lakeside Mountains, 

Confusion Range, and Needle Range (figs 2, 5, 6), are in 

areas more remote from shoal-water settings and show less 

upward change to the top of the Sadlick sequence than those 

in west-central Utah. In sections such as those in the 

Confusion and Needle Ranges, which form part of the House 

Range-Wah Wah plate (fig. 2), initiation of the succeeding 

Maughan sequence is evidenced by an interruption in 

siliciclastic deposition and by the widespread appearance of 

lithosome MA.Rh.Lm at the base of the Maughan (fig. 6) 

that reflects at least some increase in bottom-water oxygenation and more open marine circulation. The 

Sadlick-Maughan sequence boundary perturbs the generally 

oxygen deficient sedimentary record of the Delle event in 

these sections, even though the nature of the ensuing strata 

of the Maughan sequence continues to reflect some degree 

of oxygen deficiency.

MAUGHAN SEQUENCE

The Maughan sequence includes Upper Mississippian 

strata ranging from late Meramecian to late Chesterian in 

age. Within the study area it includes a laterally complex 

variety of both carbonate and terrigenous-clastic rocks and 

is at least a few hundred meters thick in most places. 

Because of its relatively greater thickness and stratigraphic 

complexity as compared with the underlying sequences, 

unresolved structural complications within most exposures 

obscure the details of internal stratigraphy and the record of
H20 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

subsidiary marine transgression and regression within the 

Maughan sequence. Nonetheless, this sequence as a whole 

corresponds to a major cycle of transgression and regression.

The flooding event defining the base of the Maughan 

sequence in west-central Utah and responsible for forming its 

transgressive systems tract is well expressed near the line of 

the palinspastic cross section A-A' (fig. 5). Here, for example 

in the northern Stansbury Mountains at Flux, at Wig 

Mountain, and in the northern Dugway Range (figs. 2, 3), 

lithosome MA.Rh.LmWk is widespread. This sub-wave-base 

rhythmically thin to medium bedded limestone abruptly overlies the sandstones of lithosome SA.Qz.Ss that in places are 

markedly cross stratified beach and bar deposits. The possibility of reassigning the two units of SA.Rh.LmWk in the section at Flux (fig. 5) to MA.Rh.LmWk and of placing the 

sequence boundary at a lower level is discussed earlier. In the 

East Tintic district (fig. 2) lithosome MA.Rh.LmWk forms 

the upper part of the Osagean (?) to Meramecian Tetro 

Member of the Deseret Limestone (Morris and Lovering, 

1961).

Higher parts of the Maughan sequence in west-central 

and northern Utah were not studied by us in detail. Despite 

the considerable amount of surface mapping and subsurface 

interpretation available, much additional effort is required to 

fully understand the structural and sedimentological 

framework of this sequence in this area. The Maughan 

sequence succession here includes rock stratigraphic units 

such as the Uncle Joe Member (Meramecian) of the Deseret 

Limestone, Humbug Formation (Meramecian), Great Blue 

Limestone (Meramecian to Chesterian), lower part of the 

Manning Canyon Shale (Upper Mississippian to Middle 

Pennsylvanian), and still other units laterally equivalent to 

these. This succession reportedly is more than 1,000 m thick 

(Hintze, 1988). Within this thick, generally progradational 

assemblage, there is complex interfingering among deposits 

representing crinoidal shoals, quartz-sandstone beach and 

bar complexes, richly bioclastic and fossiliferous shelf 

limestones, and lagoonal shales. Lithosome MA.QzCr.Ss 

(fig. 5) includes the crinoidal limestones and sandstones of 

the Uncle Joe and part of the Humbug, both of which are 

commonly thick bedded, conspicuously cross stratified, 

high-energy, intertidal to shallow subtidal deposits. Local 

shallowing-upward cycles within this generally prograding 

assemblage are indicated by units of supratidal p-dolostone 

within the sandstones and crinoidal limestones of the 

Humbug Formation at widely separated locations such as 

Ophir Canyon in the Oquirrh Mountains and Blawn 

Mountain in the southern Wan Wan Mountains (fig. 2).

Sections in westernmost Utah provide a different 

expression of the Maughan sequence than those farther to the 

east and north in Utah, and they are more akin to those in 

adjoining parts of Nevada (fig. 6). In westernmost Utah, 

along the west side of the House Range-Wah Wah plate in 

the Confusion Range, Burbank Hills, and Needle Range 

(figs. 2, 3, 6), sections of the Maughan sequence are little

disrupted structurally and range from 350 to 450 m in thickness (Sadlick, 1965; Sandberg and others, 1980; Hintze and 

Best, 1987). The integrity of the section in the Confusion 

Range in the vicinity of Skunk Spring Canyon is especially 

well constrained by the geologic mapping of Hose and 

Repenning (1964), and this section best documents the 

complete Maughan sequence.

A few meters of evenly bedded, dense, nearly unfossiliferous lime mudstone (lithosome MA.Rh.Lm), .which 

constitutes the Skunk Spring Limestone Bed (Meramecian) 

of the Chainman Shale, is at base of the Maughan sequence 

in the Confusion Range, farther to the south in the Burbank 

Hills, and in the Needle Range (figs. 2, 6). Farther to the 

north at Granite Mountain (fig. 2) a few lenticular beds of this 

limestone are intercalated through about 20 m of black shale 

of lithosome MA.Ms, which at this locality forms the base of 

the Maughan sequence, overlying lithosome SA.LaDo.St of 

the Sadlick sequence. At the sequence boundary here, 

Webster and others (1984, p. 28) reported the important 

discovery of a surface of disconformity overlain by a bed of 

coarse-grained, sandy, limestone conglomerate containing 

endothyrid-bearing clasts of the mid-Meramecian "Mamet 

Foraminifer***Zone 14." According to Webster and others 

(1984), at Granite Mountain goniatites and endothyrids of 

Mamet zone 15, a zone well up in the Meramecian, characterize the basal part of the Maughan sequence, which consists 

of interbeds of lithosome MA.Rh.Lm in lithosome MA.Ms. 

Mamet zone 15 endothyrids also were reported by Webster 

and others (1984) to be present in the conspicuous unit of 

bioclastic limestone (of lithosome MA.En.Gr) a few meters 

higher in the section at Granite Mountain.

In the Cherry Creek Range (fig. 2) lithosome 

MA.Rh.Lm is more than 20 m thick, including intercalations 

of black siltstone and argillite. In the Goshute Range at 

Whitehorse Pass (fig. 2) this lithosome, with some interbeds 

of calcareous siltstone, is several tens of meters thick and has 

at its base about a meter of cross-stratified crinoidal grainstone.

Returning to the section in the Confusion Range (figs. 

2, 3, 6), above lithosome MA.Rh.Lm and forming the 

thickest part of the Maughan sequence in westernmost 

central Utah and adjacent Nevada are strata equivalent to the 

Camp Canyon Member of the Chainman Formation (of 

Sadlick, 1965). Strata of the Camp Canyon generally form 

an upward transition from black mudstone and shale 

(lithosome MA.Ms) at the base, to interbedded black 

mudstone and evenly bedded, notably spiculitic, 

organic-rich, lime mudstone (lithosome MA.Ms&Sp.Lm), 

and then to mainly spiculitic lime mudstone (lithosome 

MA.Sp.Lm). All of these lithosomes represent restricted, 

oxygen-deficient, stagnant-marine deposition except for the 

foreshoal and shoal limestones of lithosome MA.En.Gr., 

which are in the lower part of the Camp Canyon succession. 

The areally restricted lithosome MA.En.Gr grades upward 

from lithosome MA.Ms, through pellet, calcisphere,
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H21

endothyrid packstones, to more open marine crinoidal 

grainstone at its top. The top of this lithesome marks a 

subsidiary sequence boundary, probably the top of a 

third-order sequence within the second-order Maughan 

sequence. This subdivision within the lower part of the 

Maughan sequence could be laterally extensive, but stratigraphic control for its recognition away from east-central 

Utah is presently lacking.

In the upper part of the Maughan sequence in the 

Confusion Range, the spiculitic limestones of lithosome 

MA.Sp.Lm grade upward into bioclastic limestones of 

lithosome MA.Bc.Pk, which is a catchall roughly equivalent 

to the Willow Gap Limestone Member of the Chainman 

Formation (of Sadlick, 1965). In its lower part, bioclastic 

limestones of lithosome MA.Bc.Pk are intercalated with 

black shale and contain a restricted-marine fauna 

distinguished by an abundance of gastropods. Limestones 

higher in the succession have more open marine shelly 

faunas, and those at the top of lithosome MA.Bc.Pk are 

crinoidal grainstones having large-scale cross-stratification. 

A disconformity marked by a concentration of detrital 

phosphorite separates these fossiliferous limestones in the 

Confusion Range from the overlying Jensen Member (of 

Sadlick, 1965) of the Chainman Shale (Sandberg and others, 

1980) and marks the top of the Maughan sequence.

The sequence boundary at the top of the Maughan 

sequence approximates the boundary between Mamet 

endothyrid zones 18 and 19, and it roughly coincides with 

the base of the Rhipidomella nevadensis brachiopod zone 

that is customarily placed at the top of the Chesterian 

Series (Webster and others, 1984). Sections of the 

Maughan sequence from Granite Mountain southward to 

the Needle Range (fig. 2) are along strike and generally 

similar to the section in the Confusion Range (fig. 6). 

Together, they describe a major late Meramecian to late 

Chesterian cycle of marine transgression and regression, 

marked, at least locally, by internal subsidiary transgressive-regressive cycles and by disconformities at its bottom 

and top.

At locations such as the Cherry Creek Range and White 

Horse Pass and those farther south in easternmost Nevada 

(fig. 2), the Maughan sequence is mostly black mudstone 

and shale containing increasing amounts of quartzitic 

sandstone in higher parts of the section. These strata of 

lithosome MA.Ms (fig. 6, appendix) are mostly, if not 

wholly, equivalent to the upper part of the sequence, above 

the probable third-order sequence boundary shown within 

the Maughan sequence in figure 6. Their lateral relationships 

to the more calcareous equivalent part of the sequence in the 

Confusion Range and at Granite Mountain, and their relation 

to the black mudstone of lithosome MA.Ms below the 

probable third-order sequence boundary within the Maughan 

is presently unknown.

DISCUSSION

As would be anticipated in a foreland area, the Upper 

Devonian and Mississippian stratigraphic record of western 

Utah and adjoining Nevada is complicated by conspicuous 

lateral and vertical variations in sedimentation that reflect 

crustal instability. Comprehension of this record is 

hampered by a bewildering array of lithostratigraphic names 

used in a variety of different ways. The application of 

sequence stratigraphy to these rocks eliminates many 

semantic and interpretational problems that encumber their 

understanding. Recognition of the major depositional 

sequences among them, according to the depositional 

environments of the lithosomes that make up the systems 

tracts forming these sequences, provides a natural classification from which inference can be drawn about original 

paleogeographic settings, paleotectonic controls on deposition, and subsequent structural disruption.

Salient features common to all five of the upper 

Frasnian through Mississippian sequences recognized in 

western Utah and adjoining Nevada are as follows: (1) they 

were deposited on the shelf, rather than within deep-water 

basins and on slopes; (2) their highstand systems tracts 

generally prograded westward away from the continent, 

although this pattern is perturbed by paleotectonic features 

such as the Wendover high and possibly the Stansbury 

uplift; and (3) they include no terrigenous elastics that were 

obviously shed eastward from the Antler orogen. Parts of 

the Langenheim, Gutschick, Sadlick, and Maughan 

sequences are characterized by restriction of the shelf and by 

the entrapment of fine-grained siliciclastic sediment that 

otherwise would have bypassed the shelf. This suggests that 

the more outboard parts of the shelf were episodically silled 

by the tectonic development of positive relief during 

deposition of these sequences. The Morris sequence, on the 

other hand, is primarily composed of carbonate rocks, 

shows no effects of restricted environments other than those 

associated with evaporitic conditions in its progradational 

highstand systems tract, and includes some of the most 

regionally, even interregionally, extensive lithosomes. Its 

deposition was apparently controlled more by eustasy than 

regional tectonism.

The Pilot Shale, represented by rocks included in the 

Langenheim and Gutschick sequences, was interpreted by 

Goebel (1991b) as having been deposited continentward of 

the forebulge that would have resulted from initial 

overthrusting of the margin by the Roberts terrane according 

to the model of lithospheric flexural loading (Speed and 

Sleep, 1982). Strata assigned to the Pilot Shale are, however, recognized as far west as the eastern limit of the Roberts terrane (fig. 1) (Merriam, 1963; Johnson and Visconti, 

1992), such that any such positive element that controlled 

deposition on the Late Devonian shelf is now buried beneath 

Mesozoic thrust sheets, if not by original Antler-age 

displacement of the Roberts terrane. Thus the nature of the
H22 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

Devonian margin and its relation to the Antler orogen 

remains inferential, as does an explanation of the source for 

the fine-grained terrigenous elastics in the Pilot Shale.

A more compelling case can be made for development 

of an Antler-related forebulge during Mississippian time 

(Goebel, 199la). The Wendover high (fig. 3) may have been 

part of this feature, although its trend is uncertain because of 

palinspastic problems resulting from the complex 

contractional and extensional tectonic history of this region. 

Another, contemporaneous positive area, the "Ely arch," was 

postulated by Skipp (1979) to have existed southwest of the 

Wendover high in Nevada, and it could have been part of the 

same forebulge trend; however, even more so than in the 

case of the Wendover high, uncertainties surround the 

evidence for the Ely arch and its paleogeography. By Late 

Mississippian time, structural relief on the Wendover high 

amounted at least locally to about 200 m over a distance of 

about 200 km (fig. 5). This relief of approximately one part 

in a thousand was produced during a period of time that 

cannot be quantified precisely on any rational basis but was 

probably on the order of millions of years. Thus, although 

the effect on strata that were deposited near sea level is 

dramatic, the magnitude of the tectonic deformation that 

produced the Wendover high is by any measure relatively 

minor. The localized, domelike shape of this high (fig. 3) 

may have resulted from intersection of a forebulge with a 

pre-existing Precambrian zone of weakness extending westward from the Uinta trend. Relief attributable to basement 

control has been interpreted by Dorobek and others (1991) to 

have influenced Devonian-Mississippian deposition farther 

to the north in the Antler foreland.

The eastern limit of fine-grained siliciclastic 

deposition, under restricted-marine conditions on the shelf, 

shifted eastward from Late Devonian to Early Mississippian 

time, perhaps in response to eastward forebulge migration 

(Goebel, 1991b); however, although the paleogeography of 

possible forebulge features such as the Wendover high is 

somewhat dependent on palinspastic assumptions, this 

particular positive element probably remained in generally 

the same position during much of mid-Mississippian time. 

This interpretation, and the relatively small effect of 

contemporaneous tectonism on the carbonate rocks of the 

Morris sequence, indicates that eastward migration of foreland features during Antler orogenesis was episodic rather 

than gradual. Either way, this eastward shift of the effects on 

shelf deposition of Antler tectonism tends to corroborate 

models for this tectonism involving progressive overthrusting of the Antler orogen onto the continental margin from 

mid-Late Devonian through Early Mississippian time.

The thickest accumulation of the Upper Mississippian 

Maughan sequence is in west-central Utah where it is mainly 

composed of progradational shallow-marine deposits as 

compared with the thinner, mainly shaly section of the 

sequence farther west in westernmost Utah and Nevada. At 

least in Utah, deposition during this time possibly was

controlled by intracratonic basins whose development is not 

necessarily attributable to Antler orogenesis.

In view of these various indications of tectonic control 

on sedimentation in the distal Antler foreland, it therefore 

came as a surprise to us that the major-order depositional 

sequences that are apparent in the stratigraphic record of this 

foreland in Utah and adjacent Nevada are evidently the same 

as the worldwide eustatic ones recognized by Ross and Ross 

(1985, 1988). On a summary diagram correlating Lower 

Carboniferous depositional sequences of northwest Europe, 

Russia, the mid-Continent of the United States, and the 

southwestern United States (Ross and Ross, 1988, fig. 6), 

several of the most major episodes of coastal onlap stand out 

as being correlative in magnitude and age interregionally. In 

terms of the stratigraphic names applied by Ross and Ross 

(1988) to the Mississippi Valley-Illinois Basin succession, 

these major eustatic episodes in the history of Early 

Carboniferous sea-level history occur at (1) the base of the 

"'Glen Park'-Hannibal" interval (at or near the 

Devonian-Mississippian boundary), (2) the top of this same 

interval (within the Kinderhookian), (3) the top of the 

"Chouteau" interval (at the Kinderhookian-Osagean 

boundary), (4) within the "St. Louis" interval (at the 

boundary between Mamet endothyrid zones 14 and 15 

within the Meramecian), and (5) at the top of the 

"Degonia-Grove Church" interval (in the upper Chesterian). 

The age constraints on deposition of the Gutschick, Morris, 

Sadlick, and Maughan sequences in Utah and adjacent 

Nevada strongly suggest that they correlate with these major, 

interregional eustatic episodes. That this is so for the 

sea-level record of a region not included in the synthesis by 

Ross and Ross (1988) is strong validation of the eustatic 

pattern that they observed. The meaning of this for the Antler 

foreland is that eustasy, not regional tectonism, was the 

primary control on the major that is, second-order depositional sequences in the distal foreland. Local tectonic 

features, such as the Stansbury uplift, the hypothetical 

forebulge(s) related to Pilot sedimentation, and the 

Wendover high, had the effect of modulating this eustatic 

cyclicity on a relatively small, but still substantial, 

geographic scale.

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H26 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

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Published in the Central Region, Denver, Colorado 

Manuscript approved for publication November 17,1994 

Edited by Judith Stoeser 

Graphics by Gayle Dumonceaux, Springfield&Springfield, and

the authors 

Photocomposition by Gayle Dumonceaux
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H27

APPENDIX DESCRIPTION OF 

LITHOSOMES

Occurrence. Typified by the Willow Gap Limestone 

Member of the Chainman Formation (of Sadlick, 1965) in 

the Confusion Range.

This appendix includes descriptions, interpretations of 

depositional environments, and occurrences of the 

lithosomes whose relationships are shown in text figures 5 

and 6. Abbreviations of lithosome names are formed of letter 

symbols, or groups of symbols, that are separated by periods 

and represent the sequences, modifiers, and rock types as 

listed.below.

SEQUENCE MODIFIER ROCK TYPE

MA Maughan

SA Sadlick

MO Morris

GU Gutschick

LA Langenheim

Be

Cr

Cs

DC

Di

Do

En

La

Ma

Oo

Os

Pd

Pr

Pt

Qz

Rh

Sp

Bioclastic

Crinoidal

Calcisphere

Desiccated

Diffusely

interbedded

Dolomitic

Endothyrid

Laminated

Massive

Oolitic

Ostracode

Peloidal

Primary

Pellet

Quartzose

Ds

Gr

Lm

Ms

Pk

Ss

St

Wk

Dolostone

Grainstone

Lime mudstone

Mudstone or shale

Packstone

Sandstone

Sillstone

Wackestone

Rhythmically bedded

Spiculitic

MAUGHAN SEQUENCE

MA.Bc.Pk BIOCLASTIC PACKSTONE (TEXT FIG. 6)

Description. Various limestones, mainly packstone 

containing crinoidal and other open-marine bioclasts; 

crinoidal grainstone increasingly important upsection, some 

beds of which are as thick as a few meters and contain 

large-scale cross-stratification. Crinoidal packstone and 

grainstone form resistant cyclic units several meters thick 

intercalated with recessive units of lime mudstone and wackestone. Shelly faunas are dominated by gastropods in lower 

part; corals are conspicuous in upper part. In the Confusion 

Range upper contact is a dissolution residue of crinoidal 

milestone about 1 m thick overlain by about 10 cm of detrital 

phosphorite at the base of the overlying Jensen Member of 

the Chainman Formation (of Sadlick, 1965).

Depositional environment. Subtidal, increasingly 

open marine and high energy conditions upward within this 

cyclic, composite lithesome.

MA.Sp.Lm SPICULITIC LIME MUDSTONE 

(TEXT FIG. 6)

Description. Evenly medium bedded, impure, 

spiculitic, lime mudstone; minor interbedded black mudstone and yellow-brown siltstone. Body fossils are generally 

absent except for a few levels that contain a restricted fauna 

dominated by gastropods and Leiorhynchoidea-]ite 

brachiopods.

Depositional environment. Restricted, low-energy 

marine.

Occurrence. Camp Canyon Member of Chainman 

Formation (of Sadlick, 1965), especially upper part in the 

Confusion Range and also in the Burbank Hills and Needle 

Range and at Granite Mountain.

MA.Ms&Sp.Lm MUDSTONE AND SPICULITIC LIME 

MUDSTONE (TEXT FIG. 6)

Description. Black mudstone with interbeds and 

intercalated units of impure, spiculitic lime mudstone; rare 

planar-laminated beds as thick as 20 cm of bioclastic 

(crinoidal, brachiopod, endothyrid, and so forth), spiculitic 

packstone.

Depositional environment. Restricted, mainly low 

energy marine. Bioclastic packstones are interpreted as 

storm deposits by stratigraphic context.

Occurrence. Camp Canyon Member of Chainman 

Formation (of Sadlick, 1965), especially middle part in the 

Confusion Range and also in the Burbank Hills and Needle 

Range and at Granite Mountain.

MA.En.Gr ENDOTHYRID GRAINSTONE 

(TEXT FIG. 6)

Description. Grades upward in the Confusion Range 

from discrete thin to medium beds of fine-grained 

bioclast-pellet packstone and grainstone with impure 

limestone partings in lower part to diffusely layered, 

vaguely cross stratified, massive bioclast-intraclast grainstone in upper part. Bioclast assemblage near base mainly 

consists of endothyrids, bryozoa, and calcispheres; crinoid 

columnals and brachiopod fragments are more important 

upsection, but endothyrids are conspicuous throughout. At 

Granite Mountain, bioclasts have oolitic coatings.

Depositional environment. Upward progression 

from restricted, low-energy marine to foreshoal and shoal.
H28 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

Occurrence. Recognized only within the lower part 

of the Camp Canyon Member of the Chainman Formation 

(of Sadlick, 1965) in the Confusion Range and at Granite 

Mountain. Lithosome was misassigned to the "Skunk Spring 

Limestone" by Webster and others (1984) at Granite Mountain where base is locally a bedding-parallel fault.

MA.Ms MUDSTONE (TEXT FIG. 6)

Description. Black mudstone and shale; sparse 

phosphatic, goniatite-bearing concretions in lower part (as in 

the Needle and Confusion Ranges and at Granite Mountain). 

Minor discontinuous interbeds of crossbedded quartzite and 

coal are present in the Cherry Creek Range and at other 

locations in easternmost Nevada.

Depositional environment. Restricted, mainly low 

energy marine to paralic.

Occurrence. Forms lower part of Camp Canyon 

Member of the Chainman Formation (of Sadlick, 1965) from 

the Needle Range north to Granite Mountain; predominant in 

the Maughan sequence in easternmost Nevada, as at Trough 

Spring Canyon, Dutch John Mountain, and Ward Mountain, 

and in the Cherry Creek Range. As discussed in the text, 

these thick sections of MA.Ms in easternmost Nevada are 

mostly, if not entirely, above the level of the probable 

third-order sequence boundary within the Maughan 

sequence. They correspond to the typical concept of the 

Chainman Shale.

MA.QzCrJSs QUARTZOSE AND CRINOIDAL 

SANDSTONE (TEXT FIGS. 5,6)

Description. Quartz sandstone, crinoidal quartz 

sandstone, and quartz-sandy crinoidal grainstone; rudely 

tabular to cross-stratified bedding; some herringbone 

cross-stratification. Lithosome includes some calcareous 

siltstone and rare units of evaporitic p-dolostone; sandstone 

is locally cemented by secondary dolomite.

Depositional environment. Shallow-marine foreshore, backshore, and offshore bar.

Occurrence. West-central and southwestern Utah; 

included in either the Uncle Joe Member of the Deseret 

Limestone or the Humbug Formation. Only the lower part of 

this lithosome is represented in text figures 5 and 6; its total 

thickness is nowhere well constrained because of structural 

complications but is on the order of hundreds of meters.

MA.Rh.LmWk RHYTHMICALLY BEDDED LIME 

MUDSTONE AND WACKESTONE (TEXT FIG. 5)

Description. Rhythmically thin to medium bedded 

lime mudstone and wackestone containing siliciclaslic

partings or calcareous siltstone interbeds. Silicification of 

limestone outward from siliciclastic partings or interbeds 

transforms some sections into thinly interlayered limestone 

and chert. Bioclasts are inconspicuous but are open-marine 

types such as crinoid columnals. Lithosome may include 

intercalated units of calcareous siltstone where transitional 

into MA.QzCr.Ss.

Depositional environment. Open marine, mainly 

below wave base.

Occurrence. West-central Utah in the northern 

Dugway Range, East Tintic district, and Gilson Mountains 

and at Flux and Wig Mountain; generally equivalent to the 

Tetro Member of the Deseret Limestone or to the upper and 

main part of the Tetro where lithosomes SA.Qz.Ss and 

SA.Rh.LmWk have been included in the Tetro as at Ophir 

Canyon (Sandberg and Gutschick, 1984).

MA.Rh.Lm RHYTHMICALLY BEDDED LIME 

MUDSTONE (TEXT FIG. 6)

Description. Rhythmically bedded lime mudstone; no 

megafossils; sparse radiolarians and ostracodes visible in 

thin section.

Depositional environment. Low-energy marine; 

below wave base.

Occurrence. Skunk Spring Limestone Bed of 

Chainman Shale in the Needle Range, Burbank Hills, and 

Confusion Range. Farther to the north at Granite Mountain, 

lithosome is represented by individual beds of decimeter-scale 

thickness in black shale of lithosome MA.Ms containing phosphate nodules. In the Cherry Creek Range, lithosome is more 

than 20 m thick and contains black siltstone and argillite in 

graded beds near top. At White Horse Pass, lithosome is 

several tens of meters thick and is in part interbedded with 

calcareous siltstone; both basal and uppermost parts of lithosome are composed of cross-stratified, crinoidal grainstone.

SADLICK SEQUENCE

SA.Pr.Ds PRIMARY DOLOSTONE (TEXT FIG. 5)

Description. Peritidal cyclic dolostone; alternating 

units of finely crystalline, partly laminated and fenestral, 

light-colored, dense p-dolostone and massive, sugary, 

eogenetic secondary dolostone; minor interstratifiedquartzite. 

Lithosome overlies partly dolomitized, thick-bedded, crinoidal packstone or grainstone.

Depositional environment. Supratidal evaporitic 

restricted marine to intertidal carbonate shoal.

Occurrence. Upper part of Brazer Dolomite at Samak 

("unit 8" of Nichols and Silberling, 1991) and in the 

Crawford Mountains.
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H29

SA.Cr.WkPk CRINOIDAL WACKESTONE AND 

PACKSTONE (TEXT FIG. 5)

SA.Os.Lm OSTRACODE LIME MUDSTONE 

(TEXT FIGS. 5,6)

Description. Diffusely interstratified, conspicuously 

crinoidal, bioclast-peloid wackestone, packstone, and lime 

mudstone.

Depositional environment. Open marine, above 

wave-base carbonate ramp.

Occurrence. In lower part of Brazer Dolomite at 

Samak ("unit 7" of Nichols and Silberling, 1991).

SA.Qz.Ss QUARTZOSE SANDSTONE (TEXT FIGS. 5,6)

Description. Cross-stratified, massive, or plane-bedlaminated quartz sandstone; mostly carbonate cemented. 

Lithosome includes some cross-stratified sandstone with 

crinoidal bioclasts admixed, locally grading into quartz-sandy 

crinoidal grainstone, and it commonly includes interstratified 

units of lithesome S A.LaDo.St.

Depositional environment. Variety of shallow-marine 

foreshore, backshore, and offshore bar environments.

Occurrence. West-central and southwestern Utah 

from the northern Dugway Range and Ophir Canyon 

southward to Blawn Mountain.

SA.Rh.LmWk RHYTHMICALLY BEDDED LIME 

MUDSTONE AND WACKESTONE (TEXT FIGS. 5,6)

Description. Rhythmically thin to medium bedded 

lime mudstone and spiculitic wackestone; siliciclastic and 

bioclast-drift partings weakly developed; bioclasts are 

comminuted shelly fossils and crinoid columnals. Rare, 

massive to graded (storm?) beds of crinoidal grainstone are 

present at Ophir Canyon and Rock Canyon.

Depositional environment. Low-energy marine; 

some open-marine influence.

Occurrence. Lower parts of Brazer Dolomite and 

Deseret Limestone in west-central Utah at Samak ("unit 6" 

of Nichols and Silberling, 1991), Ophir Canyon (lower 

carbonate unit of Tetro Member of Deseret Limestone of 

Sandberg and Gutschick, 1984), Rock Canyon (upper 

limestone unit of phosphatic member of Deseret Limestone 

of Sandberg and Gutschick, 1978), and Dog Valley (lower 

part of Delle Phosphatic Member of Deseret Limestone of 

Sandberg and Gutschick, 1984). The two units of this 

lithosome intercalated with quartzose sandstone in the upper 

part of the Sadlick sequence at Flux (text fig. 5) could be 

assigned to the overlying Maughan sequence, as discussed 

earlier.

Description. Regularly thin to medium parted dense 

lime mudstone, megascopically featureless except for 

characteristic nodules of secondary wood-grained chert 

(DeCelles and Gutschick, 1983); lime-mudstone fabric of 

very finely comminuted bioclastic material; microscopically 

recognizable bioclasts of mainly ostracodes.

Depositional environment. Restricted, low-energy 

marine; oxygen-deficient marine water possibly of abnormal 

salinity.

Occurrence. Widespread in all but the northwest part 

of the study area as persistent units hi deposits influenced by 

the Delle phosphatic event in the Delle Phosphatic Member 

of the Woodman Formation (southern Lakeside Mountains; 

Sandberg and Gutschick, 1984; Silberling and Nichols, 

1991), and the lower parts of the Deseret Limestone (for 

example, Ophir Canyon), Brazer Dolomite (for example, 

Samak; Silberling and Nichols, 1991), and Needle Siltstone 

Member of the Chainman Formation (of Sadlick, 1965). In 

more eastern sections, as in the Crawford Mountains, and at 

Samak, Dog Valley, and Blawn Mountain, initial deposition 

of this lithosome coincides with onset of the Delle 

phosphatic event.

SA.LaDo.St LAMINATED DOLOMITIC SILTSTONE 

(TEXT FIGS. 5,6)

Description. Secondarily dolomitic siltstone to very 

fine grained sandstone; characteristically planar laminated 

except where intensely burrowed on stratification; planar or 

irregular platy parting. Initial deposition of this lithosome 

coincides with onset of the Delle phosphatic event; base is 

marked by a hardground developed on the underlying 

carbonate rocks and a basal lag of detrital phosphate. 

Chertified phosphatic radiolarian limestone, isolated beds of 

ostracode lime mudstone, and layers of phosphatic mudstone and detrital phosphate are interstratified in lower part.

Depositional environment. Restricted; oxygendeficient to anoxic, abnormal marine water undergoing 

prolonged episodes of stratification; highly organic and 

reducing in-sediment conditions (Silberling and Nichols, 

1992).

Occurrence. Widespread, except for the northwesternmost and easternmost sections in study area. Lithosome 

forms most of the Needle Siltstone Member of the Chainman Shale (as at Whitehorse Pass, Cherry Creek Range, 

Trough Spring Canyon, and Granite Mountain south to Needle Range), the Woodman Formation (at Gold Hill and 

northern Dugway Range), and the lower part of the Deseret 

Limestone. In the southern Lakeside Mountains, lower part
H30 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

of lithesome is defined as the Delle Phosphatic Member of 

the Woodman Formation (Sandberg and Gutschick, 1984).

SA.Di.WkPk DIFFUSELY INTERBEDDED WACKESTONE 

AND PACKSTONE (TEXT FIGS. 5,6)

Description. Diffuse, irregular, and gradational 

interlayering of medium to thick layers of conspicuously 

crinoidal packstone and pelletal wackestone, subordinate 

winnowed lags of crinoidal grainstone. Besides crinoid 

columnals, a variety of brachiopods, corals, and mollusks are 

well represented as megafossils and bioclasts. Nodules and 

bedding-plane stringers of secondary chert are commonly 

abundant.

Depositional environment. Open marine, above wave 

base, subtidal ramp.

Occurrence. Widespread as the upper unit of the 

Gardison Limestone and locally also the Joana Limestone. 

Lithosome extends beyond limits of underlying lithosome 

SA.La.Pk, which are shown in text figures 2 and 3.

SA.Cr.Gr CRINOIDAL GRAINSTONE (TEXT FIGS. 5,6)

Description. Massive, medium to very thick 

parted crinoidal grainstone; locally exhibits large-scale 

cross-stratification.

Depositional environment. Open marine, subtidal 

dunes and shoals.

Occurrence. Widespread in the Gardison Limestone 

and upper part of Joana Limestone as isolated units as thick 

as several meters; thicker successions interrupted by 

subordinate units of lithosome SA.Rh.LmWk.

SA.Oo.Gr OOLITIC GRAINSTONE (TEXT FIGS. 5,6)

Description. Massive, thick to very thick parted, 

commonly cross stratified oolitic grainstone.

Depositional environment. Open marine, subtidal to 

intertidal shoals.

Occurrence. In lower part of Gardison Limestone and 

the correlative upper part of the Joana Limestone. Lithosome 

is particularly well developed from the Confusion Range 

south to Blawn Mountain and at Samak and is represented by 

thin units or stringers as far north as Sally Mountain and as 

far west as Trough Spring Canyon.

SA.Rh.Wk RHYTHMICALLY BEDDED WACKESTONE 

(TEXT FIG. 6)

Description. Thin- to medium-bedded limemudstone, 

wackestone, and packstone; bedding rhythmic in evenly to 

nodular fashion; partings between beds marked by

fine-grained siliciclastic material and bioclast drifts. 

Allochems include pellets and varying abundances of 

open-marine bioclasts such as crinoid columnals. Occasional 

large (to diameter 0.3 m), oblate-hemispheroid shape, 

colonial corals in growth position within wackestone beds. 

Occasional stratigraphically isolated TA or TAB teds of 

crinoidal grainstone.

Depositional environment. Offshore ramp, mostly 

below normal wave base but containing discrete bioclastic 

storm beds.

Occurrence. Forms most or all of upper part of Joana 

Limestone at Ward Mountain north to the Cherry Creek 

Range in eastern Nevada and uppermost unit of the Joana in 

the Confusion Range in easternmost central Utah.

SA.La.Pk LAMINATED PACKSTONE 

(TEXT FIGS. 2-3,5,6)

Description. Conspicuously laminated or quasilaminated, pelletal, uniformly fine grained packstone and 

grainstone including occasional, discrete, mostly medium 

thick, normally or reverse-graded interbeds of coarse 

intraclasts and skeletal fragments. Laminated limestone is 

present in planar sets having low-truncation-angle crossbedding and contains abraded, mainly well sorted crinoidal bioclasts, as well as pellets. Coarsely bioclastic beds contain 

mainly crinoid columnals, coralline debris, and conspicuous 

large gastropods (Silberling and Nichols, 1992).

Depositional environment. Open marine, shallow 

subtidal to intertidal. Coarsely bioclastic interbeds are 

interpreted as tempestites.

Occurrence. Widespread in Utah as shown in text 

figures 2 and 3; forms greater share of Gardison Limestone 

from Crawford Mountain south to the Gilson Mountains, 

west to Sally Mountain and Wig Mountain, and east to 

Samak; also in the Needle Range in the upper part of the 

Joana Limestone.

MORRIS SEQUENCE

MO.Pr.Ds PRIMARY DOLOSTONE (TEXT FIGS. 5,6)

Description. Peritidal cyclic dolostone. Units of 

light-colored, finely crystalline, p-dolostone overlie and are 

intercalated with massive, sugary, eogenetic (Nichols and 

Silberling, 1980) secondary dolostone.

Depositional environment. Supratidal and intertidal; 

evaporitic restricted marine.

Occurrence. Southeastern sections in study area; 

observed as a discrete unit at West Mountain, Gilson Range, 

Star Range, and Blawn Mountain. Beds and thin units of 

p-dolostone are present within lithosome MO.Dc.Lm as far 

northwest as the East Tintic district and the Needle Range.
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H31

MO.Dc.Lm DESICCATED LIME MUDSTONE 

(TEXT FIGS. 5,6)

Description. Dense, mostly massive, partly fenestral, 

lime mudstone, peloid grainstone, and microbially planar 

laminated to stromatolitic lime mudstone.

Depositional environment. Mainly intertidal; 

restricted, partly evaporitic lagoonal.

Occurrence. Widespread at top of Fitchville Formation, observed from Sally Mountain southward to Blawn 

Mountain and as far east as West Mountain. In west-central 

Utah lithosome includes the "pink lithographic limestone" 

(Morris and Lovering, 1961) and the spectacularly 

stromatolitic "curley limestone bed" (Proctor and Clark, 

1956). Farther to the west, lithosome is present in middle 

part of the Joana Limestone in the Confusion Range, 

Burbank Hills, Needle Range, Trough Spring Canyon, and 

southern Red Hills.

MO.PdCr.Gr PELOIDAL CRINOIDAL GRAINSTONE 

(TEXT FIGS. 5,6)

Description. Massive grainstone, commonly exhibiting large-scale crossbedding. Crinoidal allochems are 

conspicuous but characteristically heavily micritized and 

commonly subordinate to peloids, which, as viewed in thin 

section, represent both rounded intraclasts and totally 

micritized parts of crinoidal grains.

Depositional environment. Subtidal shoals.

Occurrence. Widespread, as a continuous, progradational unit within the Fitchville Formation of west-central 

Utah. Lithosome forms the major part of cycles as thick as 

several meters in the lower part of the Joana Limestone in 

westernmost Utah and is present as units interstratified with 

lithosome MO.Rh.Wk in eastern Nevada south of the 

Wendover high.

MO.Rh.Wk RHYTHMICALLY BEDDED WACKESTONE 

(TEXT FIGS. 5,6)

Description. Rhythmically thin to medium bedded 

wackestone and packstone; beds planar, undulating, or even 

nodular depending on diagenetic and later alteration. 

Fine-grained siliciclastic impurities define partings between 

beds, or repetitive, laterally continuous chert layers replace 

partings and adjacent parts of limestone beds. Lithosome has 

markedly diverse assemblage of recognizable bioclasts 

derived from bryozoans, mollusks, brachiopods, ostracodes, 

foraminifers, and corals; crinoidal grains are conspicuous. 

Grain size of bioclasts from bed to bed is commonly 

conspicuously different; some beds are normal graded. Basal 

contact is sharp and is commonly marked by a sandstone bed 

as at Fitchville Ridge. In the Confusion Range, 1.7 m of 

quartz sandstone at base of the Joana Limestone grades

upward into this lithosome and disconformably overlies 

lithosome GU.St.

Depositional environment. Well-oxygenated offshore ramp; below fairweather wave base but storm 

influenced.

Occurrence. Widespread in lower parts of Fitchville 

Formation and Joana Limestone; forms a larger proportion 

of the Morris sequence toward the west and northwest within 

the study area.

MO.Di.WkPk DIFFUSELY INTERBEDDED WACKESTONE AND PACKSTONE (TEXT FIG. 5)

Description. Diffuse, irregular, and gradational 

medium to thick interlayers of crinoidal packstone and 

pelletal wackestone. In addition to crinoid ossicles, 

allochems are bioclasts of comminuted brachiopod and 

bryozoan debris as well as some peloids.

Depositional environment. Open-marine; above 

wave base, subtidal carbonate ramp.

Occurrence. Locally the basal lithosome of the 

Morris sequence (and Fitchville Formation) in the southern 

Lakeside Mountains, where its base is a sharp contact 

marked by a concentration of conodonts and other insolubles 

("unit 2" of Silberling and Nichols, 1992). Lithosome forms 

most of Joana Limestone in the Leppy Hills where it 

gradationally overlies a few meters of lithosome MO.Rh.Wk 

(Nichols and Silberling, 1993).

GUTSCHICK SEQUENCE

GU.MaCr.Pk MASSIVE CRINOIDAL PACKSTONE 

(TEXT FIG. 5)

Description. Massive crinoidal and peloidal packstone. Bedding characteristics at Fitchville Ridge are 

obscured by solution compaction, but diffuse, irregular 

grain-size interlayering is suggested in lower part of 

lithosome and large-scale cross-stratification in upper part; 

coarsely intraclastic layers are present near top.

Depositional environment. Open marine, shoal, and 

inner ramp continentward of lithosome GU.Bc.Pk.

Occurrence. Lower part of Fitchville Formation; best 

exposed at Fitchville Ridge. Elsewhere, as at West 

Mountain, Gilson Mountains, and Star Range the nature of 

this lithosome is obscured by secondary dolomitization or by 

faulting.

GU.Bc.Pk BIOCLASTIC PACKSTONE (TEXT FIGS. 3,5,6)

Description. Thin-bedded, irregularly slabby toplaty, 

mottled impure limestone composed of nodules and thin 

lenses of fine-grained, gray bioclastic packstone enclosed in
H32 EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN

anastomosing streaks and layers of argillaceous to silty 

limestone. Lithosome contains well-sorted, fine-grained 

bioclasts derived mainly from crinoids, brachiopods, and 

bryozoans, and their predominance over pellets or other 

kinds of allochems is characteristic. Figures .7-10 in Silberling and Nichols (1992) illustrate this lithosome.

Depositional environment. Well oxygenated, open 

ramp.

Occurrence. West-central Utah southward from Sally 

Mountain and Becks Spur to Gilson Mountains and probably 

Star Range as the Pinyon Peak Limestone (or upper member 

of the Pinyon Peak of Sandberg and Poole, 1977). Palinspastically, it forms a well-defined north-northeast-trending belt 

(text fig. 3).

: GUSt SILTSTONE (TEXT FIG. 6)

Description. Mainly platy, irregularly parted, 

carbonate-cemented, quartzose siltstone that grades into 

secondarily dolomitic siltstone and fine-grained silty 

secondary dolomite in upper part. Lithosome is calcareous 

and contains sparsely distributed brachiopod shells in lower 

part. Nodular interbeds of pyritic, pelletal packstone contain 

oncolitic or foraminifera-encrusted shell fragments and 

diverse body fossils (Gutschick and Rodriguez, 1979) in 

lowest several meters.

Depositional environment. Semirestricted shallow 

marine near base to evaporitic marine at top.

Occurrence. Leatham Member and upper member of 

the Pilot Shale of Sandberg and others (1989) in the 

Confusion Range; similar to upper part of Leatham 

Formation at Leatham Hollow.

GU.WkSt WACKESTONE AND SILTSTONE 

(TEXT FIG. 6)

Description. Rythmically thin bedded to nodular, 

neomorphosed, spicular (?) wackestone containing partings 

and interbeds of calcareous siltstone; sparse crinoid 

columnals and brachiopod shells as drifts on siliciclastic 

parting surfaces; progressively dolomitized toward top. At 

top lithosome grades up into 2.5 m of quartz sandstone 

disconformably underlying lithosome MO.Rh.Wk.

Depositional environment. Subtidal marine; upper 

part obscured by dolomitization.

Occurrence. Unique to Burbank Hills, where it forms 

the highest part of the Pilot Shale.

GU.Ms MUDSTONE (TEXT FIG. 6)

Description. Black, finely fractured mudstone or 

fissile shale; calcareous near base, silty in part; partly 

silicified and radiolarian bearing near top. Base is marked in

the Confusion Range by distinct lag deposit that contains 

coarse quartz' grains, abraded crinoid columnals, and a 

concentration of conodonts. Lag deposits were also reported 

at bottom and top of silicified upper part in the Confusion 

Range by Gutschick and Rodriguez (1979)

Depositional environment. Low energy, at least 

partially marine.

Occurrence. In upper part of Pilot Shale in the 

Confusion Range and Burbank Hills; lower part of Leatham 

Formation at Leatham Hollow. In the Confusion Range the 

lithosome includes the "lower black shale" (Gutschick and 

Rodriguez, 1979) of the Leatham Member and the 

uppermost part of the lower member of the Pilot (Sandberg 

and others, 1989); at Leatham Hollow it includes the "lower 

black shale" of the Leatham Formation (Gutschick and 

Rodriguez, 1979).

LANGENHEIM SEQUENCE

LA?.Dc.Gr DESICCATED GRAINSTONE 

(TEXT FIGS. 5,6)

Description. Massive, light-colored, megascopically 

unfossiliferous, peloidal grainstone, peloid-calcisphere 

wackestone, and lime mudstone, some having fenestral 

texture. Bioclasts are poorly represented and mainly 

calcispheres and ostracodes. Erosion surfaces are present 

throughout beneath thin layers of fine-grained sedimentary 

breccia, peloid grainstone, or stringers of calcareous 

sandstone. Upper and lower contacts with other lithosomes 

are abrupt, marked by a concentration of quartz grains, and 

interpreted to be disconformable.

Depositional environment. Restricted lagoonal to 

desiccated intertidal.

Occurrence. Blawn Mountain, Star Range, and on 

Pinyon Peak (which lies between Rattlesnake Ridge and 

Fitchville Ridge in the East Tintic district). Lower member 

of the Pinyon Peak Limestone of Sandberg and Poole (1977).

LA.LaDo.St LAMINATED DOLOMITIC SILTSTONE 

(TEXT FIGS. 3,5,6)

Description. Predominantly planar laminated or quasilaminated, secondarily dolomitic, yellow-brown-weathering 

siltstone and very fine grained sandstone and silty secondary 

dolostone, which in exceptional exposures are present as 

meter-scale, coarsening- and thickening-upward cyclic intervals. Silt and sand is composed mainly of quartz and minor 

amounts of feldspar and mica. Subordinate intercalated units 

include (1) slump-folded to monolithologically brecciated, 

thin-bedded, impure wackestone and packstone; (2) discrete 

graded beds exhibiting Bouma-sequence internal layering (in 

the Cherry Creek Range, Confusion Range, and Leppy Hills);
UPPER DEVONIAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES IN THE DISTAL ANTLER FORELAND H33

(3) tongues of lithosomes LA.PtCs.Pk and LA.Bl.Ms; (4) 

discrete packets of ripple-drift, crosslaminated fine-grained 

sandstone (in the Cherry Creek Range); (5) massive 

sandstone; and (6) gutter casts (in the Cherry Creek Range). 

Transition upsection to foreshore sandstone having 

herringbone cross-stratification at top of lithesome in the B urbank Hills.

Depositional environment. Mainly storm influenced, 

subtidal, and restricted lagoonal by stratigraphic context.

Occurrence. Forms much of the lower member of the 

Pilot Shale, widespread from the Leppy Hills southward to 

the Needle Range and palinspastically west of limit shown 

in text figure 3.

LA.Ms MUDSTONE (TEXT FIG. 6)

Description. Black siliciclastic mudstone or shale 

and subordinate laminated siltstone in platy-weathering 

stringers to thin intercalated units. Infrequent impure lime 

mudstone concretions and lenticular beds contain radiolarians; other fossils are conspicuously absent. Lithesome is 

gradational and intercalated with underlying and overlying 

lithosomes.

Depositional environment Low-energy, restricted 

marine by stratigraphic context.

Occurrence. Lower member of Pilot Shale; thickest 

continuous section in the Confusion Range but also present 

as conspicuous units in the Burbank Hills, northern Red 

Hills, and Cherry Creek Range and at Granite Mountain and 

Ward Mountain.

LA.PtCs.Pk PELLETAL CALCISPHERE PACKSTONE 

(TEXT FIG. 6)

Description. Thin-bedded, characteristically burrow 

mottled to nodular, pelletal packstone and wackestone 

distinguished by restricted bioclast assemblage mostly 

limited to calcispheres and ostracodes.

Depositional environment. Restricted lagoonal: 

Occurrence. Upper part of West Range Limestone, as 

in the Burbank Hills; Indian Ranch Tongue of the Guilmette 

Formation of Sandberg and others (1989) in the Cherry 

Creek Range.

LA.PtCr.Pk PELLETAL CRINOIDAL PACKSTONE 

(TEXT FIG. 6)

Description. Thin-bedded, characteristically burrow 

mottled to nodular, pelletal packstone and wackestone 

distinguished from lithosome LA.PtCs.Pk by conspicuous 

crinoid columnals and comminuted shelly bioclasts. Body 

fossils are mostly absent. Rare massive (storm?) beds of 

crinoidal grainstone are present locally.

Depositional environment. Open-marine subtidal 

carbonate flat.

Occurrence. West Range Limestone, forming either 

all of this formational unit (as in the Needle Range) or its 

lower part gradationally beneath lithosome LA.PtCs.Pk (as 

in the Burbank Hills). Commonly included in the Guilmette 

Formation, forming its upper part as recognized in the Leppy 

Hills (Schneyer, 1990), Confusion Range (Hintze, 1974), or 

Needle Range (Hintze and Best, 1987). Transitional upward 

through a few meters into lithosome LA.LaDo.St in the 

Confusion Range.

LA.Rh.Lm RHYTHMICALLY BEDDED 

LIME MUDSTONE (TEXT FIG. 6)

Description. Rhythmically thin to medium bedded, 

nodular, dense, bioturbated lime mudstone; mostly devoid 

of allochems but characterized by rare rhynchonellid 

brachiopod shells.

Depositional environment. Restricted lagoonal.

Occurrence. "Ca/vt/wna-bearing limestone unit" of 

Sandberg and others (1989) in the northern Red Hills and 

Cherry Creek Range (Jones, 1990). Lithosome forms one or 

more units at or just above base of Langenheim sequence.

* U.S. GOVERNMENT PRINTING OFFICE: 1995-673-046/86103
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stratigraphy, and structural relations in certain coal-resource areas.

Oil and Gas Investigations Charts show stratigraphic information for certain oil and gas fields and other areas having petroleum potential.

Miscellaneous Field Studies Maps are multicolor or black-andwhite maps on topographic or planimetric bases on quadrangle or irregular areas at various scales. Pre-1971 maps show bedrock geology in relation to specific mining or mineral-deposit problems; post-1971 maps 

are primarily black-and-white maps on various subjects such as environmental studies or wilderness mineral investigations.

Hydrologic Investigations Atlases are multicolored or black-andwhite maps on topographic or planimetric bases presenting a wide range 

of geohydrologic data of both regular and irregular areas; the principal 

scale is 1:24,000, and regional studies are at 1:250,000 scale or smaller.

Catalogs

Permanent catalogs, as well as some others, giving comprehensive 

listings of U.S. Geological Survey publications are available under the 

conditions indicated below from USGS Map Distribution, Box 25286, 

Building 810, Denver Federal Center, Denver, CO 80225. (See latest 

Price and Availability List.)

"Publications of the Geological Survey, 1879-1961"may be purchased by mail and over the counter in paperback book form and as a set 

microfiche.

"Publications of the Geological Survey, 1962-1970"may be purchased by mail and over the counter in paperback book form and as a set 

of microfiche.

"Publications of the U.S. Geological Survey, 1971-1981"may be 

purchased by mail and over the counter in paperback book form (two volumes, publications listing and index) and as a set of microfiche.

Supplements for 1982, 1983, 1984, 1985, 1986, and for subsequent years since the last permanent catalog may be purchased by mail 

and over the counter in paperback book form.

State catalogs, "List of U.S. Geological Survey Geologic and Water-Supply Reports and Maps For (State)," may be purchased by mail and 

over the counter in paperback booklet form only.

"Price and Availability List of US. Geological Survey Publications," issued annually, is available free of charge in paperback booklet 

form only.

Selected copies of a monthly catalog "New Publications of the 

U.S. Geological Survey" is available free of charge by mail or may be obtained over the counter in paperback booklet form only. Those wishing a 

free subscription to the monthly catalog "New Publications of the U.S. 

Geological Survey" should write to the U.S. Geological Survey, 582 National Center, Reston, VA 22092.

Note.-Prices of Government publications listed in older catalogs, 

announcements, and publications may be incorrect. Therefore, the prices 

charged may differ from the prices in catalogs, announcements, and publications.
Silberling and others UPPER DEVONTAN-MISSISSIPPIAN STRATIGRAPHIC SEQUENCES, UTAH AND NEVADA U.S. Geo