U.S. Department of the Interior

U.S. Geological Survey

Professional Paper 1776–B

Studies by the U.S. Geological Survey in Alaska, 2008–2009

The Cannery Formation—Devonian to Early Permian 

Arc-Marginal Deposits Within the Alexander Terrane, 

Southeastern Alaska
FRONT COVER

Rocks of the Cannery Formation in the type area Cannery Cove.
The Cannery Formation—Devonian to Early Permian 

Arc-Marginal Deposits Within the Alexander Terrane, 

Southeastern Alaska

By Susan M. Karl, Paul W. Layer, Anita G. Harris, Peter J. Haeussler, and Benita L. Murchey

Professional Paper 1776–B

U.S. Department of the Interior

U.S. Geological Survey 

Studies by the U.S. Geological Survey in Alaska, 2008–2009
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Suggested Citation

Karl, S.M., Layer, P.W., Harris, A.G., Haeussler, P.J., and Murchey, B.L., 2010, The Cannery Formation—Devonian to Early Permian 

arc-marginal deposits within the Alexander Terrane, Southeastern Alaska, in Dumoulin, J.A., and Galloway, J.P., eds., Studies by 

the U.S. Geological Survey in Alaska, 2008–2009: U.S. Geological Survey Professional Paper 1776–B, 45 p.
 III

Contents

Abstract...........................................................................................................................................................1

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

Cannery Formation.........................................................................................................................................2

 Type Area—Cannery Cove Section..................................................................................................3

Correlative Occurrences of the Cannery Formation on Admiralty Island ............................................7

Distinguishing Features of the Cannery Formation in the Type Area..................................................13

Rocks Assigned to the Cannery Formation on Kupreanof and Zarembo Islands .............................14

Devonian Chert-Bearing Lithostratigraphic Units in the Alexander Terrane.....................................18

Devonian Chert at Kake .....................................................................................................................18

Saginaw Bay Formation.....................................................................................................................20

Chert of Hawk Inlet.............................................................................................................................20

Mississippian Chert-Bearing Lithostratigraphic Units in the Alexander Terrane.............................20

Chert and Limestone of the Porcupine Creek-Tsirku River Area................................................22

Iyoukeen Formation............................................................................................................................22

Peratrovich Formation........................................................................................................................22

Saginaw Bay Formation.....................................................................................................................23

Summary of Mississippian Chert-Bearing Units ...........................................................................23

Pennsylvanian Lithostratigraphic Units in the Alexander Terrane......................................................23

Saginaw Bay Formation.....................................................................................................................23

Crinoidal Limestone of Keku Strait...................................................................................................23

Ladrones Limestone ...........................................................................................................................24

Klawak Formation ...............................................................................................................................24

Summary of Pennsylvanian Lithostratigraphic Units....................................................................24

Permian Lithostratigraphic Units in the Alexander Terrane.................................................................24

Halleck Formation ..............................................................................................................................24

Rocks of the William Henry Bay Area .............................................................................................25

Slate of Porcupine Creek...................................................................................................................26

Correlative Permian Rocks in British Columbia on Trend with Porcupine Creek.....................26

Pybus Formation..................................................................................................................................27

Discussion.....................................................................................................................................................28

Implications of Early Permian Sedimentary Facies in the Alexander Terrane..................................30

Early Permian Metamorphic Rocks ..........................................................................................................32

Early Permian Intrusive Rocks ..................................................................................................................32

Summary and Conclusions.........................................................................................................................35

Acknowledgments ..................................................................................................................................35

References Cited..........................................................................................................................................36
IV 

Figures

1. Southeastern Alaska, showing location of the Alexander terrane .............................................3

 2. Geologic map showing distribution of early Permian rocks, and rocks 

that were metamorphosed during the early Permian ................................................................4 

 3. Late Devonian through Permian lithostratigraphic columns ........................................................5

 4. Rocks of the Cannery Formation dated by fossils in type area ....................................................6

 5. Photomicrographs of rocks of the Cannery Formation at Cannery Cove ...................................7

 6. Photomicrographs of argillite of the Cannery Formation at Snug Cove....................................11

 7. Photomicrographs of rocks of the Cannery Formation at Windfall Harbor..............................14

 8. Compositional diagrams showing immobile-trace-element chemistry 

of volcanic rocks associated with the Cannery Formation on Admiralty Island .................15

 9. Rocks of the Cannery Formation on Windfall and Kupreanof Islands.......................................16

10. Photomicrographs of rocks of the Cannery Formation on Kupreanof Island...........................17

11. Deformed slaty argillite of the Cannery Formation in southeastern Alaska.............................18

12. Southeastern Alaska, showing the distribution of Late Devonian, Early Mississippian, 

and Late Mississippian black chert and limestone in the Alexander terrane .....................19

13. Bedding and a rugose coral and volcaniclastic rocks from the type locality of the Halleck 

Formation at Halleck Harbor, Saginaw Bay, southeastern Alaska (figs. 1, 2). Limestone 

of the Pybus Formation overlying pillow basalt of the Halleck Formation and fossil hash 

of the Pybus Formation are from exposures in Saginaw Bay.................................................25

14. Southeastern Alaska, showing distribution of the late Permian Pybus Formation 

and age-equivalent rocks in the Alexander terrane ................................................................28

15. 40Ar/39Ar age spectra for minerals dated from metamorphic rocks 

on Admiralty Island ........................................................................................................................29

16. Southeastern Alaska, showing distribution of Permian sedimentary, metamorphic, 

and igneous rocks and inferred model for their tectonic setting...........................................31

17. Compositional diagrams showing geochemical affinities of Permian intrusive rocks 

of the Alexander terrane...............................................................................................................34

Tables

1. Fossil ages reported for the Cannery Formation and equivalent rocks....................................8

2. Fossil ages reported for the Pybus Formation and equivalent rocks..........................................12

3. Radiometric data for Permian metamorphic and igneous rocks

 in the Alexander terrane................................................................................................................21

4. Chemical analyses of Permian intrusive rocks................................................................................33

Appendix

Argon analytical data for Permian metamorphic and igneous rocks .................................................41
Studies by the U.S. Geological Survey in Alaska, 2008–2009

Edited by Julie A. Dumoulin and John P. Galloway

U.S. Geological Survey Professional Paper 1776–B

The Cannery Formation—Devonian to Early Permian 

Arc-Marginal Deposits Within the Alexander Terrane, 

Southeastern Alaska

By Susan M. Karl, Paul W. Layer, Anita G. Harris, Peter J. Haeussler, and Benita L. Murchey

Abstract

The Cannery Formation consists of green, red, and gray 

ribbon chert, siliceous siltstone, graywacke-chert turbidites, 

and volcaniclastic sandstone. Because it contains early 

Permian fossils at and near its type area in Cannery Cove, on 

Admiralty Island in southeastern Alaska, the formation was 

originally defined as a Permian stratigraphic unit. Similar 

rocks exposed in Windfall Harbor on Admiralty Island 

contain early Permian bryozoans and brachiopods, as well 

as Mississippian through Permian radiolarians. Black and 

green bedded chert with subordinate lenses of limestone, 

basalt, and graywacke near Kake on Kupreanof Island was 

initially correlated with the Cannery Formation on the basis 

of similar lithology but was later determined to contain 

Late Devonian conodonts. Permian conglomerate in Keku 

Strait contains chert cobbles inferred to be derived from the 

Cannery Formation that yielded Devonian and Mississippian 

radiolarians. On the basis of fossils recovered from a 

limestone lens near Kake and chert cobbles in the Keku 

Strait area, the age of the Cannery Formation was revised to 

Devonian and Mississippian, but this revision excludes rocks 

in the type locality, in addition to excluding bedded chert 

on Kupreanof Island east of Kake that contains radiolarians 

of Late Pennsylvanian and early Permian age. The black 

chert near Kake that yielded Late Devonian conodonts is 

nearly contemporaneous with black chert interbedded with 

limestone that also contains Late Devonian conodonts in the 

Saginaw Bay Formation on Kuiu Island. The chert cobbles 

in the conglomerate in Keku Strait may be derived from 

either the Cannery Formation or the Saginaw Bay Formation 

and need not restrict the age of the Cannery Formation, 

regardless of their source. The minimum age of the Cannery 

Formation on both Admiralty Island and Kupreanof Island is 

constrained by the stratigraphically overlying fossiliferous 

Pybus Formation, of late early and early late Permian age. 

Because bedded radiolarian cherts on both Admiralty and 

Kupreanof Islands contain radiolarians as young as Permian, 

the age of the Cannery Formation is herein extended to Late 

Devonian through early Permian, to include the early Permian 

rocks exposed in its type locality. The Cannery Formation is 

folded and faulted, and its stratigraphic thickness is unknown 

but inferred to be several hundred meters. The Cannery 

Formation represents an extended period of marine deposition 

in moderately deep water, with slow rates of deposition and 

limited clastic input during Devonian through Pennsylvanian 

time and increasing argillaceous, volcaniclastic, and bioclastic 

input during the Permian.

The Cannery Formation comprises upper Paleozoic 

rocks in the Alexander terrane of southeastern Alaska. In 

the pre-Permian upper Paleozoic, the tectonic setting of 

the Alexander terrane consisted of two or more evolved 

oceanic arcs. The lower Permian section is represented by 

a distinctive suite of rocks in the Alexander terrane, which 

includes sedimentary and volcanic rocks containing early 

Permian fossils, metamorphosed rocks with early Permian 

cooling ages, and intrusive rocks with early Permian cooling 

ages, that form discrete northwest-trending belts. After 

restoration of 180 km of dextral displacement of the ChilkatChichagof block on the Chatham Strait Fault, these belts 

consist, from northeast to southwest, of (1) bedded chert, 

siliceous argillite, volcaniclastic turbidites, pillow basalt, 

and limestone of the Cannery Formation and the Porcupine 

Slate of Gilbert and others (1987); (2) greenschist-facies 

Paleozoic metasedimentary and metavolcanic rocks that have 

Permian cooling ages; (3) silty limestone and calcareous 

argillite interbedded with pillow basalt and volcaniclastic 

rocks of the Halleck Formation and the William Henry Bay 

area; and (4) intermediate-composition and syenitic plutons. 

These belts correspond to components of an accretionary 

complex, contemporary metamorphic rocks, forearc-basin 

deposits, and the roots of a volcanic arc, respectively. 

The similar early Permian sedimentary, metamorphic, 

and igneous ages are inferred to represent an arc complex 

that resulted from juxtaposition of a structural lower plate 

consisting of metamorphosed Paleozoic arc rocks of the 

Alexander terrane exposed on Admiralty Island, and a 

structural upper plate consisting of stratigraphically distinct, 

unmetamorphosed Paleozoic arc rocks representing another 

component of the Alexander terrane exposed on Chichagof, 

Kuiu, and Prince of Wales Islands. The Cannery Formation 

is associated with the lower-plate package. A volcanic arc 
2 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

with magmatic ages ranging from 293 to 278 Ma formed 

during subduction of the basin between these two (or more) 

components of the Alexander terrane in southeastern Alaska. 

Metamorphic-mineral-cooling ages ranging from 273 to 

260 Ma are interpreted to date an early Permian orogenic 

event. Both the early Permian lower- and upper-plate rocks 

are unconformably overlain by late early and early late 

Permian limestone, dolostone, and conglomerate of the Pybus 

Formation that provide a minimum age for this collision. 

Introduction

The purpose of this report is to clarify the age and 

stratigraphic position of the Cannery Formation as defined 

by Loney (1964), modified by Muffler (1967), and redefined 

by Jones and others (1981), and to delineate its depositional 

environment and tectonic setting. Undated rocks that 

were provisionally assigned to the Cannery Formation by 

Muffler (1967) yielded much older fossils than those from 

rocks at the type area, but although rocks in the type area 

contain Permian fossils, the age of the unit was revised to 

Devonian and Mississippian by Jones and others (1981). 

We evaluate the composition and distribution of rocks of 

Devonian through Permian age in the Alexander terrane and 

the utility of the Cannery Formation as originally defined 

in comparison with the utility of its present definition that 

excludes rocks in the original type area. Clarification of the 

age and stratigraphic position of the Cannery Formation is 

important for documenting the depositional and structural 

history of the Alexander terrane (fig. 1). The Cannery 

Formation and equivalent units record a major tectonic event 

in the Alexander terrane, comprise basement to a belt of 

Late Triassic volcanogenic massive sulfide (VMS) deposits 

in the Alexander terrane, and provide insights into the 

tectonic setting of these VMS deposits. We herein redefine 

the Cannery Formation to include rocks of similar age and 

composition to those exposed at the type locality of the unit 

in Cannery Cove on Admiralty Island, as originally defined 

by Loney (1964), and we extend the age of the unit to include 

rocks assigned to the Cannery Formation by Muffler (1967), 

Jones and others (1981), and Brew and others (1984).

Cannery Formation

The Cannery Formation was named for thinly interbedded chert, argillite, and graywacke exposed in Cannery Cove 

on the southwest shore of Pybus Bay on Admiralty Island 

(figs. 2, 3; Loney, 1964). The unit crops out almost continuously from about 6 km south of Cannery Cove to the north 

shore of Donkey Bay (fig. 2), a distance of almost 10 km. 

In Pybus and Gambier Bays, the unit includes volcaniclastic 

graywacke, pillow basalt, and pillow breccia. The chert, argillite, and graywacke vary widely in color, ranging from red 

through gray to bright spruce green, but are predominantly 

green and gray (fig. 4). The chert and argillite contain radiolarians and sponge spicules. Bryozoan debris of Permian age was 

recovered from massive calcareous graywacke interbedded 

with chert and argillite at the top of the type section in Donkey 

Bay and near the mouth of Pybus Bay (locs. 20 and 21, fig. 2 

and table 1). Corals, a brachiopod, and bryozoans from three 

additional fossil localities in graywacke, chert, and argillite 

between Pybus and Gambier Bays (locs. 17-19, fig. 2 and table 1) 

yielded similar ages (Loney, 1964; see Alaska Paleontologic 

Database, http://www.alaskafossil.org/). At Donkey Bay, the 

fossil locality is near the contact with overlying fossiliferous 

limestone and dolostone of the Pybus Formation that contains 

Permian brachiopods (loc. 45, fig. 2 and table 2; Loney, 1964; 

see Alaska Paleontologic Database, http://www.alaskafossil.

org/), which provide a minimum age for the Cannery Formation. The sandstone at Cannery Cove is a graywacke containing feldspar, mafic volcanic fragments, calcareous bioclastic 

debris, and less than 8 volume percent quartz in a matrix that 

constitutes at least 15 volume percent of the sandstone (Loney, 

1964). The graywacke sandstone grades to chert within single 

turbidite beds. Radiolarians are distributed throughout the 

beds in both the sandstone and the chert (figs. 5B-5D). Feldspar clasts in the sandstone and argillite include andesine and 

albite; the albite is interpreted to be secondary (Loney, 1964). 

Other secondary minerals include quartz, chlorite, calcite, 

and clay (fig. 5A). Locally, sandstone and conglomerate of the 

Cannery Formation contain angular clasts of quartz-veined 

black chert resembling chert of the underlying Hood Bay 

Formation. Conglomerate of the overlying Pybus Formation 

and Hyd Group contains angular to rounded clasts of red and 

blue-green bedded chert that resemble chert of the Cannery 

Formation. Although no upper or lower depositional contacts of the Cannery Formation have been observed, clasts of 

underlying veined black chert in conglomerate of the Cannery 

Formation and clasts of red and green chert of the Cannery 

Formation in overlying limestone of the Pybus Formation and 

in Late Triassic conglomerate of the Hyd Group are inferred 

to indicate stratigraphic unconformities above and below the 

Cannery Formation. The Hood Bay Formation consists of 

deformed, quartz-veined black chert and argillite containing 

Ordovician graptolites (Carter, 1977). The chert and argillite 

grade upward to carbonaceous argillite, chert, chert sandstone 

grit, meter-scale lenses of pillow basalt, and thinly laminated 

black limestone containing Silurian-Devonian conodonts 

(A.G. Harris, written commun., 1995). Crisscrossing quartz 

veinlets in the Hood Bay Formation, which are absent in the 

Cannery Formation, are inferred to represent a pre-Cannery 

deformation event. 

 An argillite-dominant facies of the Cannery Formation was mapped in the Snug Cove area of Gambier Bay by 

Lathram and others (1965) (fig. 6). Graywacke-chert turbidite 

beds in Windfall Harbor (fig. 2), similar to those in Cannery 

Cove, contain Mississippian and Mississippian through Permian radiolarians (loc. 16, fig. 2 and table 1; B.L. Murchey, 

written commun., 1997). Radiolarians are common in the chert 
 Cannery Formation 3

AG 

AG 

YO 

SD 

SD 

NX 

YT 

YT 

AX 

AX 

SZ 

BR 

PR 

GS 

BA 

WA 

HO 

PR 

WR 

CC 

RB 

RB CO 

AG AG 

CG 

PW GD 

CG 

CG 

AA 

AG 

WS 

AA 

WR 

SM 

CG 

YT 

YA 

NAM 

ST 

AX 

YT 

SM QN 

ST 

YT 

CC 

CD 

WR 

SM 

KO 

MT 

CK 

MT 

QN 

NAM 

KI 

MO 

OC 

132

144

156 168

72

52

56

144

132

CA 

PE 

PE 

PE 

KY 

KY 

TG,NY 

PC 

IZ 

+

+

+

+

+

+ + +

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+ + + +

+

+

+

+ +

+

+

+

North American Craton

Pacific Plate

Juan de 

Fuca Plate

--

- - -

- -

-

- -

-

-

- - -

- - - -

-

-

-

- -

-

- -

-

- - -

-

-

-

- -

-

-

-

-

-

OF 

NAM 

AX 

WR 

+

+ +

+

+

EXPLANATION

Craton 

North American cratonal 

margin

Cratonal terrane

Proximal pericratonal terrane

Distal pericratonal terrane

Upper Mesozoic island-arc

terrane

Lower Mesozoic island-arc

terrane

PE Peninsular terrane

Wrangellia - - - - - Overlap assemblage

Contact

Strike-slip fault

Thrust fault

Pericratonic Terranes

Accreted Terranes Accretionary Complexes

Overlap and Intrusive Rocks

Intrusive rocks

Paleozoic and Mesozoic arc 

terrane

Alexander terrane

Oceanic basalt, volcaniclastic,

and pelagic rocks

Mixed-source clastic rocks

o

o o o

o

o

o

o o

Study area

Figure 1. Southeastern Alaska, showing location of the Alexander terrane (modified from Nokleberg and others, 2000, with permission).

(fig. 7B-7D), but also occur in the arenaceous parts of turbidite beds (figs. 7C, 7D). A maximum age of Mississippian is 

inferred for the Cannery Formation on Admiralty Island on the 

basis of Mississippian radiolarians from the graywacke-chert 

turbidites in Windfall Harbor and the unconformity between 

the Cannery Formation and the Ordovician through Devonian 

Hood Bay Formation.

 Type Area—Cannery Cove Section

At Cannery Cove on Admiralty Island, the type area of 

the Cannery Formation, the basal and upper contacts of the 

unit are not exposed. The section is too deformed to measure, 

but the base is inferred to be near the back of the cove, behind 

which the Hood Bay Formation is exposed on the ridge, and 
EXPLANATION

Permian mafic volcanic rocks Permian Halleck Formation Permian argillite and limestone Mississippian through Permian limestonDevonian through Permian Cannery ForDevonian through Permian Cannery ForPaleozoic metamorphic rocks with PermPermian intrusive rocks Fossil locality (tables 1 and 2) Ar-Ar age locality (table 3) Pi PMl Pal PDc Pv Phl PDca Pzm 1 2 3 4 5 6 7 89 10 11 12 13 14 15 16 17 18 19 21 20 22 232425 26 2728 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 4748 49 50 52 51 AB C D EF G H I J 54 53 0 25 50 75 100 km North Chatham Strait Fault (restored 180 km) Ketchi

Craig Suemez Island Prince of Wales Island Klawock Sukkwan Island Zarembo Island Petersburg Kake Towers Arm Duncan Canal Chatham Strait Kupreanof Sitka Chichagof Island Glacier Bay William Henry Bay Admiralty Island Pybus Bay Cannery Cove Mount Henry Clay Porcupine Creek Juneau Hawk Inlet Eagle Peak Windfall Harbor Keku Strait Saginaw Bay Halleck Donkey Bay U.S. Canada Canada U.S. Klehini River Tsirku River Harbor Gambier Bay Snug Cove Greens Creek Island Island Kuiu ClarenceStrait 24A

Figure 2. Geologic map showing distribution of early Permian rocks, and rocks that were metamorphosed during the early Permian, in the Alesoutheastern Alaska (fig. 1). Rocks south and west of the Denali-Chatham Strait dextral fault have been restored 180 km to better reflect Permi
Prince of Wales Island Saginaw Bay Kake/ Kupreanof Island Pybus Bay/ Cannery Cove Hawk Inlet/ Windfall Harbor Klehini R./ Porcupine Creek

L

G

A

B

C

G

L

C

LS

William Henry 

Bay/Chichagof

Island

EXP

Cannery Formation

Cannery Formation

Cannery Formation

Saginaw Bay Formation

Peratrovich Formation

Iyoukeen Formation

Ladrones Ls.

argillite and limestone volcanic

 rocks

Porcupine Slate of Redman and others (1985)

Hood Bay Fm.

chert 

chert and limestone

Port Refugio Fm. Pybus Formation

Pybus Formation

Pybus Fm.

Pybus Formation Halleck Formation

Freshwater 

Bay Fm.

350325300

275

250

225

375

Late Devonian

Mississippian Devonian Pennsylvanian Permian Triassic Pennsyl- vanian Late

Late

Middle

EarlyLate

Middle

EarlyEarly

Anisian Ladinian Famennian

EPOCH STAGE

Olenikian Tournaisian Visean Serpukhovian K Artinskian Sakmarian A RW Cap Wu C B M Ka G Ca

Figure 3. Late Devonian through Permian lithostratigraphic columns for key areas in the Alexander terrane, southeastern Alaska (figs. 1,2used is that of Gradstein and others (2004).
6 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Figure 4. Rocks of the Cannery Formation dated by fossils in type 

area in Cannery Cove (A) and Donkey Bay (B) and similar dated rocks 

in Windfall Harbor (C), southeastern Alaska, (figs. 1, 2).

the top of the section is slightly north and east of Donkey Bay. 

Because graywacke is present throughout the section, the type 

section is shown in figure 3 to consist of a chert-dominant 

graywacke-chert turbidite section and a graywacke-argillite 

turbidite section. The basal rocks of the exposed Cannery 

section consist mainly of 10 to 30 m of blue-green radiolarian 

ribbon chert, in graded beds 2 to 15 cm thick, with rare intercalations of graywacke grit. The ribbon chert grades upward 

to a middle section, more than 50 m thick, consisting of 75 

percent bedded gray-green chert, 20 percent graywacke-chert 

turbidites (fig. 4A), and less than 5 percent green argillite. The 

turbidites consist of fine- to coarse-grained volcaniclastic and 

bioclastic graywacke that grades to radiolarian chert within 

individual turbidite beds. Radiolarians are distributed throughout the sandstone and chert. This chert-dominant section 

grades upward to a graywacke-dominant section, more than 

30 m thick, consisting of graywacke-argillite turbidites, with 

subordinate 1- to 3-cm thick beds of greenish-gray radiolarian 

chert and cherty argillite (fig. 5). The graywacke-argillitedominant part of the section includes rare meter-scale lenses 

of orange-weathering carbonate and an argillite-matrix debris 

flow that contains blocks of intraformational graywackeargillite turbidites. This section is overlain by thick-bedded, 

meter-scale, fine- to medium-grained graywacke turbidites that 

alternate with laminated gray-brown limestone beds as much 

as 30 cm thick, and thin-bedded chert and argillite. At the top 

of the section in Donkey Bay, below Permian limestone of the 

Pybus Formation, massive calcareous coarse-grained graywacke of the Cannery Formation contains Permian bryozoan, 

foraminiferal, echinoderm, and bivalve debris (figs. 2, 4B; 

loc. 21, fig. 2 and table 1) and angular intraformational clasts 

of green radiolarian chert, plagioclase, volcanic fragments, 

and bioclastic debris in a clayey to siliceous matrix containing secondary chlorite. Quartz clasts are rare or absent. On a 

triangular quartz-feldspar-lithics (QFL) diagram, 11 samples 

plot as lithic sandstones containing less than 20 volume percent quartz+chert (Q); 9 of these samples contain less than 10 

volume percent Q (Loney, 1964). The lithic clasts are labeled 

as “chiefly volcanic” and the other lithic clasts are mainly carbonate (Loney, 1964). Well-rounded pebbles of gray and green 

chert, which are common in overlying limestone and dolostone of the Pybus Formation, support the interpretation that 

an erosional unconformity separates the Cannery and Pybus 

Formations (Loney, 1964; Lathram and others, 1965). Pervasive folding and faulting of the rocks on Admiralty Island 

preclude precise determination of unit thickness; a maximum 

thickness of “several hundred feet” for the Cannery Formation 

was inferred by Lathram and others (1965). 

B

A

C
 Correlative Occurrences of the Cannery Formation on Admiralty Island 7

Figure 5. Photomicrographs of rocks of the Cannery Formation at Cannery Cove, southeastern Alaska (figs. 1,2). A, Volcanic fragments, 

echinoderm debris, feldspar, and chlorite in graywacke. Sample 94SK054A at 10x. B, Radiolarians, feldspar, and chlorite in siliceous 

siltstone. Sample 94SK058A at 10x. C, Volcanic fragment, feldspar crystals, and radiolarians in chert. Sample 94SK059A at 10x. D, 

Graywacke-chert turbidite bedding. Sample 94SK060A at 2.5x. Plane-polarized light.

Correlative Occurrences of the 

Cannery Formation on Admiralty Island

Bryozoan debris similar to the early Permian bryozoan 

debris in Donkey Bay occurs in light-gray siliceous argillite, 

cherty phyllite, and calcareous graywacke at two fossil 

localities between Pybus and Gambier Bays (locs. 17, 

19; fig. 2 and table 1). These two fossil localities extend 

the map area of the Cannery Formation to Gambier Bay 

(Loney, 1964). East of a fault at the head of Snug Cove in 

Gambier Bay, a 2-km-thick section of a more argillaceous 

facies of the Cannery Formation consists, from west to 

east, of (1) dark-gray meta-argillite containing blocks of 

limestone that yield Devonian corals (Loney, 1964) and 

Emsian through Famennian conodonts (A.G. Harris, written 

commun., 1982), (2) streaky green-gray sheared scaly 

argillite, (3) volcaniclastic rocks, (4) lenses of cataclastic 

phyllonite, (5) turbidites consisting of argillite grading to 

chert or limestone, (6) pillow basalt and volcanic breccia, and 

(7) siliceous and carbonaceous radiolarian argillite (fig. 6) 

containing thin (millimeter to centimeter thick) flaser lenses 

of volcaniclastic siltstone, black chert, brown limestone, and 

lenses of calcareous bioclastic debris. A limestone lens in the 

black argillite contains early Late Mississippian (Meramecian) 

conodonts (loc. 54, fig. 2 and table 1; A.G. Harris, written 

commun., 1995). This section is overlain by fossiliferous 

limestone of the Pybus Formation southeast of Snug Cove, 

and by a basal limestone-matrix debris flow of the Late 

Triassic Hyd Group northeast of Snug Cove. The textures and 

rock types in the section at Snug Cove are similar to those 

typically found in accretionary complexes as defined by Hsu 

(1968) and Plafker and others (1977). Immobile-trace-element 

analysis of the volcanic rocks intercalated with argillite, 

chert, and graywacke of the Cannery Formation throughout 

the Admiralty Island map area (fig. 2) indicates a wide range 

B

D

A

C
8 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Locality

(fig. 2) Location Sample No.

USGS Coll. 

No.

Latitude

(North)

 Longitude

 (West)

QuadrangleMap 

Unit Age Fossil Source

1 Porcupine

Creek

Wright 1903 59.41665° -136.23126°

SKB4 PMl

Artinskian

(Early Permian)

brachiopods: Productus aff.

P. mammatus, Productus aff. 

P. gruenwaldti, Spirifer aff. S. 

marcoui and S. musakheylensis, 

Camarophoria aff. C. 

margaritovi

Girty8

2 Still 1983 59.41665° -136.23126° Late Mississippian corals: Siphonodandrum sp. Sando2

3 Mt. Henry

Clay 83DB229A 59.40611° -136.44223° Paleozoic orthoconic cephalopod Dutro2

4

William

Henry

Bay

56ALy126 F14667 58.70729° -135.23723

JUC4

Pal

Early Permian

fusulinids: Parafusulinella sp., 

Eoparafusulina thompsoni 

Skinner and Wild

Douglass2

Jacobsen2

5 84AF103B F14683 58.73000° -135.28667

fusulinids: Eoparafusulina 

thompsoni Skinner and 

Wild, Eoparafusulina?aff 

E.yukonensis Skinner and Wild

Douglass2

6 84SD067A F14682 58.70905° -135.21485° fusulinids: Eoparafusulina 

thompsoni Skinner and Wild

Douglass2

Jacobsen2

7 57ADu60 F14666 58.71865° -135.24387°

fusulinids: Eoparafusulina 

thompsoni Skinner and Wild, 

Eoparafusulina?aff 

E.yukonensis Skinner and Wild

Douglass2

8

84DB175D 29348-PC 58.73778° -135.34028°

JUC5

Leonardian

(late Early Permian)

conodonts: Hindeodus 

excavatus (Behnken),

Neogondolella idahoensis 

(Youngquist, Hawley, and 

Miller),CAI:5.5

Wardlaw2

84DB175D 29348-PC 58.73778° -135.34028° early Late Permian

brachiopods: Septacamera 

stupenda Grant, dictyoclostid 

productid, brachiopod 

fragments, echinoderm debris

Dutro2

9

84DB180D 29347-PC 58.73278° -135.32639 Leonardian

(late Early Permian)

conoconts: Hindeodus 

excavatus (Behnken),

Neogondolella idahoensis 

(Youngquist, Hawley, and 

Miller), CAI:5.5

Wardlaw2

84DB180D 29347-PC 58.73278° -135.32639 early Late Permian

brachiopods: Septacamera 

stupenda Grant, Spiriferella 

sp., brachiopod fragments, 

echinoderm debris

Dutro2

10 84SG077A 29780-PC 58.72833° -135.30333° Leonardian

(Early Permian)

conodonts: Hindeodus 

excavatus (Behnken),

Neogondolella idahoensis 

(Youngquist, Hawley, and 

Miller),CAI:5.5-6.0

Wardlaw2

11 Pack Creek 59AHw292 57.91496° -134.35744° SID1

PDc

Paleozoic Echinoderm and bivalve debris Dutro2

12

Eagle Peak

57AL117a 58.10715° -134.57402°

JUA2

Carboniferous or 

Permian Productid brachiopods

Cooper2,3

13 57AL117 58.10173° -134.58823° Early Permian brachiopod: Muirwoodia sp.

14 Windfall

Island 59ALy327 20225-PC 57.88111° -134.25778°

SID1

Permian

brachiopods: Muirwoodia sp., 

Spiriferella? sp., Rhynchopora 

sp., brachiopod fragments, 

ramose bryozoans, echinoderm 

debris

Dutro2,9

Duncan2,9

15

Windfall

Harbor

59ALy329 19401-PC 57.87907° -134.29104°

bryozoans: Streblascopora sp., 

Rhombotrypella sp., Polypora

sp., brachiopod: Spiriferella? 

16 94SK024A 57.86583° -134.26389° Mississippian to 

Permian

sponge spicules:

Tricranocladina?, protriaene, 

anadiaene, oxeas, strongyles, 

hexactines

Murchey5

Table 1. Fossil ages reported for the Cannery Formation and equivalent rocks of southeastern Alaska.
 Correlative Occurrences of the Cannery Formation on Admiralty Island 9

Locality

(fig. 2) Location Sample No.

USGS Coll. 

No.

Latitude

(North)

 Longitude

 (West)

QuadrangleMap 

Unit Age Fossil Source

16 94SK024C

Windfall

Harbor 57.86583° -134.26389° SID1

PDc

Mississippian? radiolarians Murchey5

17

Pybus Bay

59ALy278 57.39167° -134.12500°

SIB1

Permian

bifoliate fistuliporoid bryozoan 

debris, ramose bryozoan debris, 

fenestrate bryozoan debris, 

including Protoretepora or

Syncladia

Henblest2,4

Duncan2,4

18 59ALy276 57.38785° -134.31435° probably Permian brachiopod: Composita? Silbeling2,4

19 Snug Cove 59ALy038 18491-PC 57.40660° -134.04446° Permian

corals: Allotropiophyllum 

sp., bryozoan fragments, 

echinoderm debris

Rowett2,4

20 Pybus Bay 58ALy53 57.27285° -134.09655° Permian

fistuliporoid, trepostomatous, 

and fenestrate cryptostomatous 

bryozoan debris

Henblest2,4

Duncan2,4

21 Donkey

Bay 58ALy128 57.34052° -134.17140° Permian

fistuliporoid, trepostomatous, 

stenoporoid, and fenestrate 

cryptostomatous bryozoan 

debris, algal debris,echinoderm 

debris, foraminiferal debris

22

Kake

80DB165A MR2329 56.99692° -133.98000°

PED6

Mississippian

radiolarians: Archocyrtium(?) 

sp., and pylentonemiids, 

Spumellariina

Jones2 

Murchey2

23 80EK069D MR1525 56.98403° -133.85539° Late Paleozoic Mississippian?

radiolarians: Spumellariina 

similar to MR1613

24 80RS089A MR1609 56.95778° -133.78556° Late Devonian-Early 

Mississippian radiolarians: Spumellariina

25 80DB221B MR1614 56.99833° -133.79611° Late Devonian to 

Cenozoic radiolarians: Spumellariina

26 78-Jse-6 9905-SD 56.99451° -133.97537° Famennian conodonts: Palmatolepis cf. P. 

gracilis Branson & Mehl Harris6

27 63AMp278 57.02602° -134.02833

SDA6

Chesterian

Late Mississippian

foraminifers: Tetraxis ex gr. T. 

conica (Ehrenberg), Zellerina 

sp., Neoarchaediscus incertus 

(Grozdilova and Lebedeva)

Armstrong2,6

28 83DB162A MR4338 57.01333° -133.84722° Osagean or Meramecian, Mississippian

radiolarians: Archocyrtium(?) 

sp., Albaillella indensis Won 

Group

Murchey2

29 80SH121B MR1613 57.00111° -133.84139° Mississippian radiolarians: Archocyrtium(?) 

sp., Albaillella, Spumellariina

Jones2

Murchey2

30 Kupreanof 

Island

98SK060A

98SK060C

DR-2410

DR-2411

56.917° 133.634°

PED5

Missourian/

VirgilianWolfcampian

(Late PennsylvanianEarly Permian)

radiolarians: Pseudoalbaillella

sp. aff. P. bulbosa, 

Pseudoalbaillella sp. cf. P. 

annulata, Pseudoalbaillella sp. 

aff. P. u-forma morphotype 1, 

Paronaella? sp. A

Blome7

31

Tower Arm

33405-PC 56.771° 133.385° Kungurian (latest 

Early Permian)

conodonts: Mesogondolella 

idahoensis CAI: 5

Harris5

32 AK14752 56.796° 133.330° PED4 Carboniferous 

through Triassic conodonts

33 98SK286A 56.807° 133.334° PED5 Kungurian (Early 

Permian)

conodonts: Neogondolella cf. 

N. idahoensis

Wardlaw7

34 98SK289A 56.774° 133.333°

PED4

Kungurian (Early 

Permian)

conodonts: Neogondolella cf. 

N. idahoensis, Sweetina sp.

35 78RS226C 27400-PC 56.810° 133.312°

late MaramecianChesterian (Late 

Mississippian)

conodonts: Gnathodus 

bilineatus, Gnathodus 

commutatus commutatus CAI: 

5 1⁄2 

Harris5

Table 1. Fossil ages reported for the Cannery Formation and equivalent rocks of southeastern Alaska.—Continued
10 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Locality

(fig. 2) Location Sample No.

USGS Coll. 

No.

Latitude

(North)

 Longitude

 (West)

QuadrangleMap 

Unit Age Fossil Source

36

Duncan 

Canal

98SK078A 33406-PC 56.841° 133.305° Early-Middle 

Pennsylvanian

conodonts: Idiognathoides cf. 

I. pacificus, Neognathodus, 

Diplognathodus cf. D. 

ellesmerensis, Idioprioniodus, 

and reworked Mestognathus cf. 

M. beckmanni, Kladognathus

sp. of Late Mississippian age, 

and reworked Palmaatolepis cf.

P. rugosa , Polygnathus cf. P. 

vogesi, and Pseudopolygnathus

sp. of Late Devonian age. 

CAI: 5-6

Wardlaw7

37 BM8645I 56.802° 133.276° Pennsylvanian

conodonts: Idiognathodus sp., 

and reworked Icriodus sp., 

Palmatolepis sp., Polygnathus

sp. of Late Devonian age

Savage1

38 Keku Islets 80SH061C 27715-PC 56.92367° -134.13074°

PAD1

Ph Late Paleozoic rugose corals, in clast in 

Halleck Fm. conglomerate Sando2

39

Saginaw

Bay

65ACn1673 56.90225° -134.20621°

Pv Early Permian

Waagenoconcha sp., orthotetid, 

productids, and chonetids 

brachiopods, fusulinids: 

Parafusulina alaskensis Dunbar

Dutro2

Douglass2

40 65ACn1662 23900-PC 56.90230° -134.20628° Parafusulina alaskensis Dunbar Douglass2

41

80SK499B F-14339 56.90629° -134.22039°

chonetid braciopods, 

strophomenoid brachiopods, 

fusulinids, echinoderm debris

Dutro2

80SK499E F-14339 56.90629° -134.22039° fusulinids: Eoparafusulina 

alaskensis (Dunbar)

Douglass2 

Jacobsen2

42 80SH054D 27716-PC 56.8806° -134.1494°

Ph

Late Wolfcampian 

(earliest Permian)

brachiopods: Arctitreta 

sp., Linoproductus 

sp., Waagenoconcha 

sp., Cancrinella? sp., 

Septacamera? sp.,Choristites 

sp., Neospirifer sp., fenestrate 

bryozoans

Dutro2

43 2247C F-23004 56.91793° -134.21416° Early Permian fusulinids: Eoparafusulina 

alaskensis (Dunbar)

Douglass2

Jacobsen2

44

82DB160C 56.85551° -134.13594°

Conichnus trace fossil, burrows 

not age diagnostic but indicate 

shallow water, possibly 

intertidal environment

Dutro2

82DB160B 28824-PC 56.85551° -134.13594°

Late PennsylvanianEarly Permian

82DB160B is 3 m below 

82DB160C. fusulinids: 

Pseudofusulinella, 

Rhabdomesids Fenestelloids, 

Fistulamina? sp.,bryozoans:, 

Rhombotrypella sp., 

Streblascopora? sp., 

Trepostomes, indet.

Douglass2

Karklins2

82DB160A 28824-PC 56.85551° -134.13594°

82DB160A is 7 m below 

82DB160B. fusulinids, 

including the rugose coral 

Lophophyllidium sp.

Sando2

54 Gambier

Bay 94SK047A 32410-PC 57.42659° -133.91987° SDB6 PDc

middle to late 

Meramecian

(early Late 

Mississippian)

conodonts: Pa elements 

Gnathodus homopunctatus 

Zeigler, juvenile Pa elements 

Gnathodus semiglaber Bischoff 

and Gnathodus texanus

Roundy, Pa element fragments 

Gnathodus, sp., Kladognathus, 

sp., and Volgelgnathus 

campbelli Rexroad. CAI: 5-5.5

Harris5

Table 1. Fossil ages reported for the Cannery Formation and equivalent rocks of southeastern Alaska.—Continued
 Correlative Occurrences of the Cannery Formation on Admiralty Island 11

Table 1. Fossil ages reported for the Cannery Formation and equivalent rocks of southeastern Alaska.—Continued

1

McClelland, William C., and Gehrels, George E. (1990)

2

Data for published and unpublished fossil reports are cited from http://www.alaskafossil.org

3

Lathram and others (1959)

4

Loney (1964)

5 Unpublished written report from paleontologist

6

Jones and others (1981)

7

Karl and others (1999)

8

Wright (1904); Eakin (1919)

9

 Lathram and others (1965)

Paleontologists: Augustus K. Armstrong: foraminifers, G. Arthur Cooper: brachiopods, Raymond C. Douglass, Linda Jacobsen: fusulinids, Helen Duncan: 

corals and bryozoans, J. Thomas Dutro: megafossils, brachiopods, G.H. Girty: brachiopods, R.E. Grant, brachiopods, A.G. Harris: conodonts, L.G. Henbest: 

bryozoans, David L. Jones, Benita Murchey, Charles Blome: radiolarians, O.L. Karklins: bryozoans, Charles L. Rowett: Permian corals, W.J. Sando: corals, 

Norm Silberling: pelecypods, brachiopods, B.R. Wardlaw: conodonts.

CAI: color alteration index for conodonts.

Quadrangles: JU: Juneau, PA: Port Alexander, PE: Petersburg, SD: Sumdum, SI: Sitka, SK: Skagway. 

Map Units as on figures. 1, 2.

Figure 6. Photomicrographs of argillite of the 

Cannery Formation at Snug Cove, southeastern 

Alaska (figs. 1, 2). A, Bedding and cleavage. 

Sample 94SK046A at 10x in plane-polarized light. B, 

Carbonaceous and siliceous composition. Sample 

94SK046A at 10x under crossed nicols.

A

B
12 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Locality

(fig. 2) Location Sample No. USGS Coll. No.

Latitude

(North)

Longitude

(West)

Quadrangle Unit Age Fossil Source

8

William 

Henry 

Bay

84DB175D 29348-PC 58.73778° -135.34028°

JU-C5 Pal

Leonardian

(late Early 

Permian)

conodonts: Hindeodus excavatus (Behnken),

Neogondolella idahoensis (Youngquist, Hawley, 

and Miller),CAI:5.5

Wardlaw2

84DB175D 29348-PC 58.73778° -135.34028° early Late 

Permian

brachiopods: Septacamera stupenda Grant,

dictyoclostid productid, brachiopod fragments, 

echinoderm debris

Dutro2

9

84DB180D 29347-PC 58.73278° -135.32639 Leonardian

conodonts: Hindeodus excavatus (Behnken),

Neogondolella idahoensis (Youngquist, Hawley, 

and Miller),CAI:5.5

Wardlaw2

84DB180D 29347-PC 58.73278° -135.32639 early Late 

Permian 

brachiopods: Septacamera stupenda Grant, 

Spiriferella sp., brachiopod fragments, echinoderm debris

Dutro2

45

Pybus 

Bay

57ADu69 18345-PC 57.28227° -134.09539°

SI-B1

Pp

Permian

brachiopods: Linoproductus sp., Waagenoconcha? sp., Stenocisma cf. S. plicata (Kutorga), 

Neospirifer sp., Licharewia? sp., Squamularia? 

sp., Spiriferella sp., Spiriferella keillhavi (von 

Buch), “Dielasma” cf. “D.” plica (Kutorga) Dutro2,4

46 58ALy195a 20591-PC 57.34859° -134.12086°

brachiopods: Derbyia sp.,Chonetina? sp., Anidanthus aff. A. alatus Cooper, Waagenoconcha 

sp., Spiriferella sp., Squamularia sp., Crurithyris sp., Rhynchopora sp., bryozoan fragments, 

echinoderm debris

47 Kupreanof 

Island

83DB167A D673-PC 56.867° 133.662° PE-D5

late Roadianearly Capitanian (early 

Late Permian)

conodonts: Neogondolella phosphoriensis, 

Xaniognathus sp., CAI: 2 Wardlaw2

48 80SH128B 56.868° 133.648°

Permian

brachiopod Dutro2

49 Clarence 

Strait 68OV1461 23398-PC 56.170° 132.905° PE-A3

brachiopods: Cleiothyridina cf. C. royssiana, 

Licharewia cf. L. spitsbergiana, Neospirifir cf. 

N. striatoparadoxus, Septacamara stupenda, 

Spiriferellina cf. S. cristata, Stenoscisma sp.

Grant2

50

Saginaw 

Bay

80RS098A 27719-PC 56.771° -134.0161°

PA-D1

brachiopods: Yakovlevia sp., Spiriferella, sp., 

dictyoclostid brachiopod, stenoporoid bryozoans, pectenoid pelecypod

Dutro2

51 80SK146B 27689-PC 56.7842° -134.0228

brachiopods: Yakovlevia sp., Spiriferella, sp., 

productids. bryozoans: Fenestelloid, Rhabdomesid, Timanodictyid, Trepostomes sp., Rhombotrypella sp.

Dutro2

Karklins2

52 Halleck 

Harbor 80EK076D 28838-PC 56.9333° 56.9333°

Clasts of Pybus Formation in base of Cornwallis 

limestone contain brachiopods Spiriferella sp., 

Septacamera stupenda Grant

Dutro2

52 Halleck 

Harbor Wright 56.9333° 56.9333° PA-D1 Pp

late Early to 

early Late

Permian

brachiopods: Cleipthyris sp., Spirifer cf. S. articus Houghton, Spirifer cf. S. blasi Vern, Spirifer

cf. S. alatus Schloth, Spirifer n.sp. cf. S. marconi

Waagen., Spiriferellina cf. S. cristata Schloth, 

Spirifer cf. S. dieniri Tsch, Camarophoria 

margaritovi, Productus cf. P. timanicus Stuck, 

Productus cf. P. aagardi Toula, Productus cf. P. 

gruenewaldti Stuck, Productus cf. P. humboldti 

D’Orb, Productus cf. P. mammatus Keys, Productus cf. P. lineatus Waagen, Productus cf. P. 

occidentalis Newberry, Productus, sp., Chonetes

sp., Dielasma sp., Rhynchopora cf. R. nikitini

Tsch, Rhynchopora cf. R. geinizianat Tsch, 

Streptorhynchus cf. S. pelargonatum Schloth,

Tsch, Septacamera pybensis Grant, bryozoans: 

Stenopora sp., corals: Zaphrentis sp., crinoid 

fragments 

Girty10

Grant11

Table 2. Fossil ages reported for the Pybus Formation and equivalent rocks of southeastern Alaska.
 Distinguishing Features of the Cannery Formation in the Type Area 13

of chemical compositions. Samples of fresh, unaltered basalt 

analyzed from volcanic rocks of the Cannery Formation on 

Admiralty Island plot in volcanic-arc, midocean-ridge, and 

ocean-island fields on discriminant diagrams (fig. 8). Similar 

variable compositions of basalt, which commonly occur in 

accretionary complexes at plate margins where subducting 

oceanic-plate rocks are structurally interleaved with trench, 

slope, and other forearc deposits, have been documented, 

for example, in the Chugach terrane (Hill, 1979; Karl, 1982; 

Nelson and Blome, 1991).

The rocks at Windfall Harbor were included in the Cannery Formation by Lathram and others (1965). Permian bryozoan 

debris was recovered from interbedded graywacke and limestone 

in Windfall Harbor (locs. 14, 15, fig. 2 and table 1). Brownish-gray 

limestone in dark-gray slaty argillite on Windfall Island (figs. 2, 

9A; loc. 14, table 1) contains the Permian brachiopod Muirwoodia

(Lathram and others, 1965; see Alaska Paleontologic Database, 

http://www.alaskafossil.org/). On the east shore of Windfall Harbor, fine-grained graywacke grades to chert in turbidite beds similar to those at Cannery Cove (fig. 4C). Radiolarians are distributed 

throughout both graywacke and chert of individual turbidite beds, 

are not considered to be reworked, and yielded Mississippian(?) 

through Mississippian-Permian ages (loc. 16, fig. 2 and table 1; 

B.L. Murchey, written commun., 1997). 

The brachiopod Muirwoodia was also recovered from 

graywacke and dark-gray slaty argillite in the middle of a section on the west shoulder of Eagle Peak on northern Admiralty 

Island (loc. 13, fig. 2 and table 1; Helen Duncan, written commun., 1957; Lathram and others, 1958, 1959, 1960). These 

rocks were included in the Cannery Formation by Lathram 

and others (1965). The section at Eagle Peak consists of pillow 

basalt and radiolarian ribbon chert, overlain by graywackeargillite turbidites, grading upward to sooty carbonaceous 

slate-phyllite that contains thin beds of gray-brown bioclastic 

limestone. This sooty slate-phyllite is indistinguishable from 

overlying Late Triassic Halobia-bearing sooty slate of the 

Hyd Group unless fossils are present. The oldest fossils in 

the Hyd Group are Middle Triassic, and the unit is commonly 

floored by a basal breccia. Limestone of the Pybus Formation 

is absent in the Greens Creek area (fig. 2). Extremely slow 

deposition, a disconformity, or a fault is inferred for the Cannery Formation-Hyd Group contact in the vicinity of Eagle 

Peak and Greens Creek. Only structural contacts have been 

observed between the Cannery Formation and greenschistfacies rocks with Permian metamorphic-mineral ages on 

Admiralty Island. 

Distinguishing Features of the Cannery 

Formation in the Type Area

 Several features distinguish the Cannery Formation, 

as originally defined on Admiralty Island, from other units in 

the Alexander terrane. Sandstone of the Cannery Formation 

is distinguished from other sandstone on Admiralty Island by 

a clast population dominated by volcanic fragments, calcareous bioclastic debris, euhedral feldspar, chert, black radiolarian cherty argillite with quartz veins, little or no quartz, and a 

siliceous matrix. The Ordovician through Devonian Hood Bay 

Table 2. Fossil ages reported for the Pybus Formation and equivalent rocks of southeastern Alaska.—Continued

Locality

(fig. 2) Location Sample No. USGS Coll. No.

Latitude

(North)

Longitude

(West)

Quadrangle Unit Age Fossil Source

53 Suemez 

Island 15ACh240 55.26531° -133.2325° CR-B4 Pl Permian

brachiopods: Cleiothyridina? sp., Spirifer cf. S. 

tastubensis, Spirifer cf. S. interplicatus, Spirifer

cf. S.schellwieni, Spirifer, sp., Griffithides, sp., 

Camarophoria cf. C. margaritovi, Productus

cf. P. humboldti, Productus cf. P. mammatus, 

Productus, sp., Chonetes cf. C. verneuilianus, 

Dielasma cf. D. bovidens, Dielasma sp., 

Globiella? sp., Septacamara stupenda, 

Spiriferellina cf. S. cristata, Stenoscisma sp., 

bryozoans: Fistulipora sp., Stenopora sp., 

Leioclema sp., corals: Zaphrentis sp. 

Girty12

Grant2

Quadrangles: CR: Craig, JU: Juneau, PA: Port Alexander, PE: Petersburg, SI: Sitka. 

Map Units as on figures. 1, 2.

CAI: conodont alteration index

Paleontologists – J.T. Dutro: brachiopods, R.E. Grant: brachiopods, O.L. Karklins: bryozoans, B.R. Wardlaw: conodonts.

Footnote numbers as on table 1.

2

Data for published and unpublished fossil reports are cited from Alaska Paleontologic Database, http://www.alaskafossil.org

 4Loney (1964)

10Wright and Wright (1908)

11Grant (1971)

12 Buddington and Chapin (1929)
14 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Figure 7. Photomicrographs of rocks of the Cannery Formation at Windfall Harbor, southeastern Alaska (figs. 1, 2). A, Cleavage in 

siliceous argillite. Sample 94SK022A at 10x under plane-polarized light. B, Carbonaceous and siliceous composition. Sample 94SK022A at 

10x under crossed nicols. C, Bedding in radiolarian chert turbidites. Dated sample 94SK024C at 5x under plane-polarized light. D, Base of 

sandstone layer in turbidites, showing volcanic fragments, feldspar, and glauconite. Sample 94SK024C at 5x under plane-polarized light.

Formation on Admiralty Island is distinguished from the Cannery Formation by its content of highly carbonaceous black 

radiolarian chert, graptolitic argillite, graywacke dominated 

by clasts of chert and argillite, massive mafic volcanic rocks, 

and 10- to 30-m thick sections of thinly laminated dark-gray 

fetid limestone. Rocks of the Hood Bay Formation are more 

deformed than those of the Cannery Formation and have a 

pervasive fabric with networks of quartz veinlets that are 

absent in the Cannery Formation. Clasts of veined, sheared 

black radiolarian chert and argillite identical to rocks of the 

Hood Bay Formation that are recognized in sandstone of the 

Cannery Formation on southern Admiralty Island indicate 

a stratigraphic relation between the two units. The Cannery 

Formation is distinguished from the Halleck Formation by 

the calcareous composition of all sedimentary rocks of the 

Halleck Formation, in contrast to the siliceous composition of 

sedimentary rocks of the Cannery Formation. Siltstone and 

chert of the Cannery Formation are distinguished from those 

of other clastic units in the Alexander terrane by the combined 

presence of undeformed radiolarians, disseminated angular 

feldspar clasts that are present even in ribbon chert, and a 

notable rarity of quartz grains. 

Rocks Assigned to the Cannery 

Formation on Kupreanof and Zarembo 

Islands

Bedded black, red, and teal-green radiolarian chert 

near Kake on Kupreanof Island (figs. 2, 3, 10A, 11C, 12) 

was lithologically correlated with the Cannery Formation by 

A

C

B

D
 Rocks Assigned to the Cannery Formation on Kupreanof and Zarembo Islands 15

TH TR

TR ALK

SHO

CA

CA

TH

MORB

WPB

VAB

10

1

1 10

0.1

0.1

0.01

0.01

Th/Yb

Ta/Yb

MORB

WIP

IAT

10 50 100 200

2

5

10

Zr ppm 

Zr/Y

1000

100

10

1 10 100

Cr ppm

Y ppm

VAB WPB

MORB E-MORB + WIP(TH) 

N-MORB

IAT

CAB, destructive

plate margin

OIA

Th Ta

Hf/3

A B

C

D

Figure 8. Compositional diagrams showing immobile-trace-element chemistry of volcanic rocks associated with the Cannery 

Formation on Admiralty Island, southeastern Alaska (figs. 1, 2). A, Th/Yb-Ta/Yb diagram of Pearce (1982). B, Zr/Y-Zr diagram of Pearce 

and Norry. (1979). Element contents are plotted in parts per million. C, Cr-Y diagram of Pearce (1982). Element content +s are plotted in 

parts per million. D, Hf/3-Th-Ta diagram of Wood (1980).

Muffler (1967). The section at Kake is almost continuously 

exposed in roadcuts and along the northwest-trending 

shoreline of Keku Strait. At the southeast and northwest ends 

of Muffler’s (1967) mapped Cannery Formation, the chert 

is overlain (contact not exposed) by fossiliferous late early 

and early late Permian limestone of the Pybus Formation, 

which isoverlain by Triassic limestone and basalt of the Hyd 

Group. The village of Kake, at the mouth of Gunnuck Creek, 

is about midway between outcrops of limestone of the Pybus 

Formation; the rocks at Kake apparently represent the base of 

a synclinal section exposed along the northeast shore of Keku 

Strait. A limestone lens in chert near Kake yielded Paleozoic 

radiolarians and Late Devonian (Famennian) conodonts 

(loc. 26, fig. 2 and table 1, fig. 10A; Jones and others, 1981). 

Late Mississippian (Chesterian) foraminifers were recovered 

about 5 km northwest of the Devonian locality (loc. 27, fig. 

2 and table 1; Jones and others, 1981). The lowest part of the 

section at Kake consists of black and teal-green ribbon chert 

and includes rare silty chert turbidite beds but not graywacke 

or graywacke-chert turbidites. This part of the chert section 
16 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Figure 9. Rocks of the Cannery Formation on Windfall and Kupreanof Islands, southeastern Alaska (figs. 1, 2). A, Early Permian 

limestone on Windfall Island. B, Bedded chert on Kupreanof Island. C, Bedded gray chert containing Mississippian and Pennsylvanian 

fossils on Kupreanof Island.

at Kake is overlain by graywacke-argillite turbidites and a 

basalt flow. Late Early or early Late Mississippian (Osagean 

or Meramecian) radiolarians (loc. 28, fig. 2 and table1; B.L. 

Murchey, written commun., 1981) were recovered from 

bedded chert near its contact with the Pybus Formation on 

northwestern Kupreanof Island. Mississippian radiolarians 

(figs. 2, 9B; locs. 23, 28, 29, fig. 2 and table 1; D.L. Jones 

and B.L. Murchey, written commun., 1981) were recovered 

from green bedded chert beneath the Pybus Formation in the 

upper reaches of Gunnuk Creek (see Alaska Paleontologic 

Database, http://www.alaskafossil.org/). Higher in the section, 

30- to 100-cm-thick beds of stylolitic chert contain abundant 

sponge spicules and radiolarians of Late Pennsylvanian and 

early Permian age (figs. 2, 9C, 10 B–D; loc. 30, fig. 2 and 

table 1; Karl and others, 1999), and include a clay-rich chertmatrix-supported debris flow that contains angular pebbles to 

boulders of gray and green chert. The chert at this locality is 

dominantly spiculitic and contains disseminated angular clasts 

of feldspar and spumellarian radiolarians, similar to the chert 

in Cannery Cove and Windfall Harbor. Stylolitic partings in the 

bedded chert suggest dissolution of carbonate and replacement 

by chert. The clasts of gray and green chert are inferred to be 

intraformational and may signal local uplift analogous to the 

uplift that contributed chert pebbles to the age-correlative early 

Permian Halleck Formation on Kuiu Island (Jones and others, 

1981; Brew and others, 1984). 

The rocks on Kupreanof Island along Towers Arm in Duncan Canal contain Permian fossils (Karl and others, 1999) and 

include green and gray siliceous phyllitic argillite, calcareous 

volcanic wacke, black carbonaceous slate, chert, pillow basalt, 

and lenses of brown-weathering gray limestone that contain 

early Permian conodonts (locs. 31-34, fig. 2 and table1; Karl 

and others, 1999). These rocks, which are apparently coextensive with the chert and graywacke to the northwest near Kake, 

represent a depositional facies change from chert-graywacke 

to argillite-graywacke, analogous to the Permian facies change 

between Cannery Cove and Gambier Bay on Admiralty Island. 

The early Permian conodonts from Towers Arm indicate 

that these rocks predate the limestone of the Pybus Formation mapped on western Kupreanof Island. The rocks have 

A C

B
 Rocks Assigned to the Cannery Formation on Kupreanof and Zarembo Islands 17

a pervasive cataclastic shear fabric with a streaky texture of 

mixed argillaceous and volcanic material that locally includes 

web structures, debris flows, blocks in matrix, and scaly argillite textures which are commonly ascribed to accretionary complexes (fig. 11A; Hsu, 1968; Cowan, 1982; Byrne, 1984). The 

rocks at Towers Arm resemble those in eastern Snug Cove on 

Admiralty Island and are nearly contemporaneous with rocks 

of both the early Permian Halleck Formation (figs. 2, 3) and the 

upper part of the Cannery Formation; their age, siliceous argillitic composition, chaotic fabric, and association with bedded 

chert on Kupreanof Island led Karl and others (1999) to assign 

them to the Cannery Formation. Similar deformed cherty 

argillite and volcaniclastic rocks that underlie Mesozoic rocks 

on Zarembo Island (figs. 2, 11B) are assigned to the Cannery 

Formation (Karl and others, 1999).

Figure 10. Photomicrographs of rocks of the Cannery Formation on Kupreanof Island, southeastern Alaska (figs. 1, 2). A, Late 

Devonian radiolarian chert at Kake. Sample 03SK019D at 5x under plane-polarized light. B, Sponge spicules and radiolarians. Dated 

chert sample 98SK060A at 5x under crossed nicols. C, Matrix-supported conglomerate, showing fabric and feldspar clasts in matrix of 

chert and hematitic clay. Sample 98SK060E at 2.5x under plane-polarized light. D, Matrix-supported conglomerate showing recrystallized 

chert clast and matrix of chert and hematitic clay. Sample 98SK060E at 2.5x under crossed nicols.

Greenschist-facies metamorphic rocks similar to those 

on Admiralty Island (Karl and others, 1999) that are 

exposed on northern Kupreanof Island are in fault contact 

with lower-grade rocks mapped as the Cannery Formation. 

Although the lower-grade rocks are extensively folded and 

faulted, they appear to grade from Devonian bedded chert 

at the southwest inferred base (near Kake) of the section to 

early Permian argillite at the northeast inferred top (near 

Duncan Canal) of the section. The true thickness of this 

depositional sequence is indeterminate. Whether the 

Devonian black chert at the base of the section is in 

continuous depositional contact with gray-red-green 

Mississippian and Permian chert, argillite, and graywacke 

that are more typical of the Cannery Formation at its type 

locality is unclear.

A

C

B

D
18 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Figure 11. Deformed slaty argillite of the Cannery Formation in 

southeastern Alaska (figs. 1, 2). A, Argillite with lenses and blocks of tuff 

and limestone from Towers Arm, Kupreanof Island. B, Argillite, chert, and 

tuff from Zarembo Island. C, Bedded black chert with quartz veins at Kake.

Devonian Chert-Bearing 

Lithostratigraphic Units in the 

Alexander Terrane

 The Alexander terrane contains numerous Devonian 

stratigraphic units. The following discussion is limited to 

Devonian units that include chert and rocks lithologically 

similar to those assigned to the Cannery Formation. The 

purpose of this discussion is to evaluate whether the Devonian 

chert at Kake should be assigned to the Cannery Formation or 

more appropriately to some other unit. The Devonian chertbearing units in southeastern Alaska form three discrete belts: 

the northern two belts, at Hawk Inlet and Kake, flank mafic 

metavolcanic rocks and massive Devonian metalimestone 

(part of the Paleozoic metamorphic rocks in fig. 2, and the 

Devonian mafic volcanic rocks in fig. 12). The southern belt 

overlies the northeast side of Late Devonian volcanic rocks 

and red beds in Saginaw Bay (fig. 12).

Devonian Chert at Kake

In the absence of fossil ages, the bedded black, red, and 

teal-green radiolarian chert exposed at Kake on Kupreanof 

Island (figs. 3, 12) was lithologically correlated with the Cannery Formation by Muffler (1967). The chert at Kake forms a 

section more than 100 m thick, but its true unit thickness is 

unknown. The section consists predominantly of chert in beds 

that range from 4 to 30 cm and average 6 cm in thickness, have 

pinch-and-swell structures, argillaceous partings, and contain 

rare intercalations of limestone, calcareous siltstone, and very 

fine-grained volcaniclastic sandstone turbidites. The chert beds 

include soft-sediment slump folds with pods of argillite in fold 

cores and thickened chert beds at fold noses. Sedimentary slump 

structures and starved ripple beds suggest quiet-water deposition on a slope or in a basin with low sediment input. The chert 

also contains sparse quartz veins (fig. 11C). The siltstone is tan 

and contains clasts of argillite. The basal chert section at Kake is 

overlain to the northwest by volcaniclastic turbidites, which are 

in turn overlain by chert that includes a limestone lens containing Late Devonian (Famennian) conodonts (loc. 26, fig. 2 and 

table 1; Jones and others, 1981). This chert is overlain by bedded chert that contains Mississippian radiolarians (loc. 22, fig. 2 

and table 1; see Jones and Murchey, 1981, in Alaska Paleontologic Database, http://www.alaskafossil.org/). The Mississippian 

chert is overlain by chert, pillow basalt, and gray and green 

chert, argillite, and fine-grained volcaniclastic rocks. 

C

B

A
0 25 50 75 100 km North

EXPLANATION

Mississippian through Permian chert (includes Pennsylvanian limestoneMississippian black limestone, chert, and argiDevonian and Mississippian thick-bedded limeLate Devonian black chert (includes Cannery FLate Devonian mafic and felsic volcanic rocksDevonian mafic metavolcanic rocksEarly Devonian mafic volcanic rocks

Ketchik

Chatham Strait Fault (restored 180 km)

Craig

Suemez Island

Prince of Wales Island

Klawock

Klakas In

Zarembo Island

Petersburg

Kake Towers Arm

Duncan Canal

Chatham Strait

Kupreanof Island

Sitka

Chichagof Island

Glacier Bay

WilliamHenry Bay

Admiralty Island

Pybus Bay

Cannery Cove

Mount Henry Clay

Porcupine Creek

Juneau

Hawk Inlet Eagle Peak

Windfall Harbor

Keku Strait

Saginaw Bay

Halleck

Donkey Bay

Harbor

Freshwater Bay

Iyoukeen Peninsula

Canada

U.S.

Tsirku River

Klehini River

Kasaan Bay

Southern arc

Northern arc

Figure 12. Southeastern Alaska, showing the distribution of Late Devonian, Early Mississippian, and Late Mississippian black chert and limestoterrane. Rocks south and west of the Denali-Chatham Strait Fault have been restored 180 km to better reflect Permian paleogeography. 
20 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Saginaw Bay Formation

The Saginaw Bay Formation was defined as a Carboniferous unit consisting of a lower volcanic member, a black chert 

member, a chert and limestone member, and an uppermost 

silty limestone member depositionally overlain by Permian siltstone, limestone, and basalt of the Halleck Formation 

(Muffler, 1967). At the head of Saginaw Bay on Kuiu Island 

(fig. 2), designated as the type locality for the Saginaw Bay 

Formation (Muffler, 1967), tuffaceous limestone of Muffler’s 

lower volcanic member later yielded conodonts of Middle 

Ordovician through Devonian age. The black chert member 

consists of thin-bedded black chert and dense, thinly laminated 

dark-gray limestone (fig. 2, 3; Muffler, 1967). One limestone 

lens in chert at the head of Saginaw Bay contains the late 

Eifelian conodont Tortodus kockelianus kockelianus (Bischoff 

and Ziegler), pb elements of Oulodus sp., and a pa element 

of Polygnathus aff. P. pseudofoliatus Wittekindt, and another 

lens yielded late Emsian through early Frasnian Polygnathus 

linguiformis linguiformis (see A.G. Harris, 1983, in Alaska 

Paleontologic Database, http://www.alaskafossil.org/). The 

chert contains Late Devonian or younger entactiniid radiolarians (D.L. Jones and B.L. Murchey, 1981, in Alaska Paleontologic Database, http://www.alaskafossil.org/). These fossils 

together indicate a Late Devonian age for the black chert 

member of the Saginaw Bay Formation. On the basis of these 

fossil reports, Brew and others (1984) extended the age of the 

Saginaw Bay Formation to Devonian through Pennsylvanian. 

The tan limestone and chert member that overlies the black 

Devonian chert is undated. Above the tan limestone and chert 

member, the chert and limestone member of the Saginaw Bay 

Formation contains early Middle Pennsylvanian foraminifers, 

brachiopods, gastropods, and bryozoans (Muffler, 1967; Dutro 

and Douglass, 1961; see Alaska Paleontologic Database, 

http://www.alaskafossil.org/). The uppermost member of the 

Saginaw Bay Formation, the silty limestone member, contains the Late Pennsylvanian and early Permian brachiopod, 

Linoproductus (see J.T. Dutro, 1983, in Alaska Paleontologic 

Database, http://www.alaskafossil.org/). This section differs 

from the section at Kake in that the Devonian chert at Saginaw 

Bay is interbedded with limestone and overlain by cherty and 

silty limestone rather than the basalt, volcaniclastic turbidites, 

and bedded chert that overlie the Devonian chert at Kake.

Chert of Hawk Inlet

Black-and-gray bedded metachert associated with greenand-gray siliceous phyllite and mafic metavolcanic semischist 

includes lenses of metalimestone containing Famennian conodonts (A.G. Harris, written commun., 2001) at two localities 

north of Hawk Inlet on Admiralty Island (Late Devonian black 

chert, fig. 12). This black metachert on Admiralty Island was 

assigned to the Retreat Group by Lathram and others (1965) 

and later assigned by Brew and Ford (1985) to their map unit 

Mzps, which corresponds exactly in area to the unit formerly 

mapped as the Retreat Group. The Hawk Inlet metachert 

was never assigned to the Cannery Formation although it is 

mapped near rocks assigned to the Cannery Formation (fig.2). 

Because the Hawk Inlet metachert section contains Late 

Devonian conodonts, it can neither be included in the Retreat 

Group, which is intruded by Neoproterozoic plutons (Karl 

and others, 2006), nor can it be assigned to a Mesozoic unit. 

The east boundary of the Devonian metachert at Hawk Inlet is 

faulted against sooty black argillite that lies along strike from 

the early Permian Muirwoodia locality in sooty argillite on the 

west flank of Eagle Peak (loc. 13, fig. 2 and table 1). The chert 

in Hawk Inlet is metamorphosed, folded, and deformed, with 

folded segregation layering that records three deformation 

events, and its stratigraphic relations are unclear. Because the 

metachert is nearly identical in age and protolith to the black 

chert at Kake, it adds support for a Late Devonian lithofacies 

that is best documented if the rocks are mapped as discrete 

units. Undated, deformed, bedded black chert also occurs in 

the Hood Bay Formation west of Pybus Bay, but it is associated with argillite containing Ordovician graptolites (Carter, 

1977), limestone containing Silurian-Devonian conodonts, 

and mafic volcanic and volcaniclastic rocks. The chert in 

Hawk Inlet and the Hood Bay Formation differ in degree of 

metamorphism and deformation from the chert at Kake and 

Saginaw Bay. Although no metamorphic minerals in the chert 

at Hawk Inlet or Hood Bay have been dated, these rocks are 

adjacent to rocks on northern Admiralty Island that have 

Devonian protoliths and have yielded Permian metamorphicmineral cooling ages (see fig. 15; table 3).

Mississippian Chert-Bearing 

Lithostratigraphic Units in the 

Alexander Terrane

Mississippian chert-bearing lithostratigraphic units are 

widespread in the Alexander terrane. They include rocks 

along the Klehini River northwest of Haines, the Iyoukeen 

Formation on Chichagof Island, the Saginaw Bay Formation 

on Kuiu Island, and the Peratrovich Formation on southern 

Prince of Wales Island (figs. 2, 3, 12). The Mississippian rocks 

in these units are described here to compare Mississippian 

chert of the Cannery Formation with other possible correlative chert-bearing units in the Alexander terrane. The cherty 

argillite members of the Iyoukeen and Peratrovich Formations 

resemble some rocks mapped as the Cannery Formation on 

Admiralty and Kupreanof Islands, but within the context of 

their dominantly fossiliferous limestone sections, they would 

not be confused with Cannery rocks. All other Mississippian 

units in the Alexander terrane contain rocks that are more 

calcareous and more carbonaceous than Mississippian rocks 

of the Cannery Formation. After restoration of 180 km of 

offset on the Chatham Strait Fault (Hudson and others, 1981), 

apparent alignment of lithofacies in the Alexander terrane 
 Mississippian Chert-Bearing Lithostratigraphic Units in the Alexander Terrane 21

Sample Symbol 

fig. 2

Latitude 

(°N) 1

Longitude 

(°W) 1 Rock type Mineral Lab/source Method Age (Ma) 2 Comment on date interpretation

Metamorphic rocks

93PH143C A 57.85806 -134.57444

amphibolite 

retrograded 

to 

greenschist 

facies

white mica

Layer-this 

study Ar-Ar 3

223.2±2.6

argon loss spectrum, weighted 

average age of 6 fractions, 

70.1% 39Ar release, MSWD = 

2.4 (error weighted by the square 

root of the MSWD), total gas = 

217.8±1.5 Ma, last 2 older steps: 

262.9±3.6 Ma

last two steps 

Permian, but 

reset by Triassic 

overprint

93PH127B B 57.86861 -134.41194 246.0±2.5

total gas age, however, argon 

loss spectra with a maximum 

age step of 268.9±2.7 Ma (7.1% 

39Ar release)

Permian 

metamorphism, 

with argon loss 

due to J or K 

metamorphism

96SK013A D 57.94528 -134.67917 256.3±4.1

weighted average age of 4 

fractions, 54.5% 39Ar release, 

MSWD = 7.6 (error weighted by 

the square root of the MSWD), 

total gas = 260.0±1.4 Ma

Permian 

metamorphism

97PH045B F 58.03000 -134.80111 amphibolite 261.8±12.0

weighted average age of 11 

fractions, 99.6% 39Ar release, 

MSWD = 131 (error weighted 

by the square root of the 

MSWD), total gas = 260.4±1.0

Permian 

metamorphism of 

sill dated at 314 

Ma (U/Pb, zircon)

97PH055B E 58.06389 -134.50778 hornblende 

gneiss hornblende 266.0±4.8

weighted average age of 

3 fractions, 64.1% 39Ar 

release, MSWD = 15.6 (error 

weighted by the square root 

of the MSWD), but excess Ar 

(errorchron age of 235±10.5 

Ma, 10 fractions, 40Ar/36Ari

 = 

1060±130

Permian 

metamorphism

91SK168A C 57.87611 -134.14667

quartzmuscovite 

schist

white mica 272.5±3.5

weighted average age of 11 

fractions, 99.2% 39Ar release, 

MSWD = 24.5 (error weighted 

by the square root of the 

MSWD), total gas = 271.6±0.7 

Ma

Intrusive igneous rocks

91SK047A G 55.72333 -132.54667 foliated 

diorite biotite

Layer-this 

study Ar-Ar

280.6±1.6 plateau age of 6 fractions, 81% 

39Ar release, MSWD = 1.5

Permian 

magmatism

91SK040A H 55.80240 -132.50080 granodiorite hornblende 278.3±10.3

weighted average age of 4 oldest 

fractions, 47.3% 39Ar release, 

MSWD = 27 (error weighted by 

the square root of the MSWD), 

total gas = 254.9±1.8 Ma

I 55.54640 -133.09430 syenite biotite

Churkin and 

Eberlein, 

1975

K-Ar

282±8

 --

J 55.01140 -132.74090 quartz 

diorite hornblende Eberlein and 

others, 1983

283

biotite 293

1 Latitudes and longitudes are NAD27.

2 All ages quoted at the 1-sigma level, MSWD: Mean Square Weighted Deviates.

3 See appendix.

Table 3. Radiometric data for Permian metamorphic and igneous rocks in the Alexander terrane, southeastern Alaska.
22 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

suggests a northwest-southeastward, northeast-facing, (present 

coordinates) orientation of the southern Alexander arc during 

the Carboniferous (fig. 12), and the carbonaceous limestonechert facies lies to the southwest of the red and green chert and 

graywacke-chert facies represented by the Cannery Formation. 

The important point is that two distinct depositional facies are 

represented by Carboniferous rocks in the Alexander terrane 

and they are geographically discrete.

Chert and Limestone of the Porcupine CreekTsirku River Area

Between the Klehini and Tsirku Rivers, thick-bedded 

metalimestone contains Devonian and Mississippian corals 

and conodonts (figs. 3, 12; loc. 2, fig. 2 and table 1; Gilbert 

and others, 1987), and includes laminated gray sooty limestone with bioclastic beds, black phyllite, and as much as 

25 percent calcareous siltstone, black slate, and dark-gray 

metasiltstone. The limestone is depositionally overlain by bedded gray chert in beds as much as 50 cm thick with phyllitic 

partings as much as 8 cm thick. The chert grades upsection 

to black cherty, pyritic argillite, with lenses of green to black 

chert as much as 80 cm thick and lenses of gray metalimestone 

as much as 80 cm thick. These carbonaceous limestone-chert 

beds overlie thick-bedded metamorphosed Devonian and 

Mississippian limestone and mafic metavolcanic rocks and 

underlie the black chert and argillite of Porcupine Creek that 

contains a Permian brachiopod (loc. 1, fig. 2 and table 1), so 

the limestone-chert beds are inferred to include Carboniferous 

rocks. Basement to these bedded rocks consists of metamorphic rocks similar to those on Admiralty and Kupreanof 

Islands that are juxtaposed by faults against the Cannery Formation. The Carboniferous limestone in the Tsirku River area 

is overlain by chert, graywacke, and argillite similar to that of 

the Cannery Formation in the Eagle Peak area on Admiralty 

Island.

Iyoukeen Formation

The Iyoukeen Formation (Loney and others, 1963, 1975) 

consists of gray fossiliferous limestone and shale best exposed 

on the Iyoukeen Peninsula of Chichagof Island (fig. 12). The 

lower member of the Iyoukeen Formation, which averages 130 

meters in thickness, is composed of dark-gray, thin-bedded, 

fine-grained limestone with thin dark-gray chert interbeds and 

lenses. The limestone contains corals, brachiopods, gastropods, and conodonts. The middle member, which averages 

200 m in thickness, consists of dark-gray, noncalcareous to 

calcareous, sparsely fossiliferous shale that grades northwestward into dark-gray, yellow-weathering shaly limestone. The 

upper member, estimated to be as much as 1,000 m thick, 

is characterized by dark-gray, medium-bedded, fossiliferous limestone with dark-gray, nodular chert lenses. Gypsum 

commonly occurs at the top of the upper member, indicating 

a tropical, arid depositional environment. The oldest fossils 

include conodonts of Kinderhookian or early Early Mississippian age (A.G. Harris, written commun., 1995; Karl, 1999). 

Corals, brachiopods, and gastropods indicate an Early Mississippian age for the lower and middle members of the Iyoukeen 

Formation and a late Late Mississippian (late Chesterian) 

age for the upper member. These rocks represent a carbonaceous limestone-chert facies of the Carboniferous rocks in the 

Alexander terrane and do not resemble correlative rocks of 

the Cannery Formation on Admiralty and Kupreanof Islands. 

The basal contact of the Iyoukeen Formation is unconformable 

on bimodal volcanic rocks of the Upper Devonian Freshwater 

Bay Formation. The upper contact of the Iyoukeen Formation is a modern erosional surface. The upward-diminishing 

proportion of shale and thickening limestone beds suggests 

that the depositional environment was shoaling over time. 

Fossil species present indicate warm, shallow water and a high 

energy environment (A.G. Harris, written commun., 1995), 

in contrast to the deepwater depositional environment represented by coeval rocks of the Cannery Formation. 

Peratrovich Formation

The Peratrovich Formation of Eberlein and Churkin 

(1970) consists of bedded dark-gray to black chert overlain by 

thin- to medium-bedded, dark-gray to black, white-weathering 

limestone with dark-gray chert nodules, exposed on Prince 

of Wales Island and small islands near Craig (fig. 12). The 

limestone contains abundant shelly fossils that indicate a 

warm, shallow-marine depositional environment (Eberlein and 

others, 1983). The lower member of the Peratrovich Formation 

consists of 70 m of thin-bedded black chert with shaly partings 

and lenses of fetid limestone that contain Early Mississippian 

crinoids, corals, and both articulate and inarticulate brachiopods. The middle member consists of at least 25 percent of 

medium-dark-gray limestone that contains mainly bryozoan 

and echinoderm fossil debris in a lime mudstone matrix, as 

well as irregular layers and nodules of black replacement 

chert. Fossils in the middle member, which is approximately 

100 m thick, indicate that it ranges in age from Osagian to 

Meramecian, or from late Early Mississippian to early Late 

Mississippian (Eberlein and Churkin, 1970). The upper member consists locally of dolomitic limestone, with less than 10 

percent black chert lenses and nodules. Limestone in the upper 

member is less than 100 m thick, medium-dark-gray, fetid, and 

contains echinoderm and bryozoan fragments in lime mudstone, as well as the corals Lithostrotion, Lithostrotionella, 

Diphyllum, and Sociophyllum and the foraminifer Tourmayella

of Meramecian age, and the foraminifer Pseudoendothyra and 

the fusulinid Eostaffela of Chesterian age (Eberlein and others, 

1983). At Shelikof Island, aquagene tuff and breccia at the 

top of the Devonian Port Refugio Formation are conformably 

overlain by thin-bedded, dark-gray to black chert and limestone of the Peratrovich Formation. Near Craig, the Peratrovich Formation overlies the late Early through Late Devonian 

Wadleigh Limestone with apparent conformity and is overlain 

by calcareous clastic rocks of the Pennsylvanian Klawak 
 Pennsylvanian Lithostratigraphic Units in the Alexander Terrane 23

Formation. The change from basal sooty argillite and chert 

to shelly limestone and dolostone suggests upward shoaling 

of a restricted basin in a warm marine depositional environment (Eberlein and others, 1983). These rocks, which closely 

resemble the Iyoukeen Formation, are a component of the carbonaceous limestone-chert facies of the Carboniferous rocks 

in the Alexander terrane; they do not resemble age-correlative 

rocks in the Cannery Formation. 

Saginaw Bay Formation

Fossil age control for the Saginaw Bay Formation has 

improved since the unit was named by Muffler in 1967. Fossils from the lower volcanic member of the Saginaw Bay 

Formation in the Keku Islets that yielded “probable Mississippian” and Pennsylvanian ages (Muffler, 1967; see Alaska 

Paleontologic Database, http://www.alaskafossil.org/) are 

now known to be Devonian in age on the basis of conodont 

collections from the basalt member and the overlying black 

chert member in Saginaw Bay (see A.G. Harris,1983, in 

Alaska Paleontologic Database, http://www.alaskafossil.org/). 

The chert and limestone member contains fossils that were 

assigned a tentative Mississippian or Pennsylvanian age (J.T. 

Dutro, oral commun., 1963, in Muffler, 1967), and the uppermost silty limestone member contains early Middle Pennsylvanian fossils (J.T. Dutro and R.C. Douglass, 1961, in Muffler, 

1967). A Carboniferous age is still inferred for the chert and 

limestone member, which consists of thin- to medium-bedded, 

light-brown-weathering calcareous chert and subordinate 

thin-bedded, medium-gray, brown-weathering, cherty fossilfragmental limestone that is locally dolomitic (Muffler, 1967). 

This unit, which is at least 122 m thick, does not resemble any 

age-correlative rocks in the Cannery Formation.

Summary of Mississippian Chert-Bearing Units

Thin-bedded black chert associated with thick sections of 

fetid, fossiliferous Mississippian limestone in the Iyoukeen and 

Peratrovich Formations represents a low-oxygen or restrictedbasin depositional environment. Calcareous chert and cherty 

fossil-fragmental limestone of the Saginaw Bay Formation 

similarly represents a shallow-marine low-oxygen depositional 

environment. Correlative varicolored ribbon chert and graywacke-chert turbidites of the Cannery Formation reflect a deepmarine, more oxygenated depositional environment. The Carboniferous rocks of the Porcupine Creek-Tsirku River area are 

less cherty than rocks of the Cannery Formation and somewhat 

resemble rocks of the Iyoukeen and Peratrovich Formations, 

but their stratigraphic context, including underlying metabasalt 

and marble and overlying Permian chert, argillite, and volcaniclastic rocks, is similar to that of the Cannery Formation. 

The carbonaceous Carboniferous chert-limestone sections of 

the Iyoukeen, Saginaw Bay, and Peratrovich Formations form 

a discrete belt that lies to the southwest of the varicolored 

Carboniferous cherts of Windfall Harbor, Cannery Cove, and 

Kupreanof Island that have been mapped in the Cannery Formation (fig. 12; Loney, 1964; Lathram and others, 1965).

Pennsylvanian Lithostratigraphic Units 

in the Alexander Terrane

Pennsylvanian lithostratigraphic units that are sparsely 

distributed in the Alexander terrane may be underrepresented, 

owing to low rates of deposition, uplift and erosion, or absence 

of datable rocks. Dated Pennsylvanian sedimentary rocks are 

dominantly limestone and calcarenite. Limestone is sparse in 

the Cannery Formation, and owing to an absence of limestone or to low rates of deposition and sparse fossils in chert 

and argillite sections, the Pennsylvanian component of the 

Cannery Formation may be poorly documented. The absence 

of Pennsylvanian limestone distinguishes the Cannery Formation from other Pennsylvanian units in southeastern Alaska. 

Saginaw Bay Formation

After the initial definition of the Saginaw Bay Formation 

by Muffler (1967), the age of the Saginaw Bay Formation was 

extended to Devonian through Pennsylvanian by Brew and 

others (1984). The lower volcanic and black chert members are 

Devonian, and the chert and limestone member contains fossils 

of tentative Mississippian or Pennsylvanian age (Muffler, 1967; 

Brew and others, 1984). Fossils of early Middle Pennsylvanian 

age were reported from the uppermost silty limestone member 

(J.T. Dutro and R.C. Douglass, 1961, in Muffler, 1967), which 

is conformably overlain by fossiliferous early Permian siltstone 

of the Halleck Formation. The thickness of the silty limestone 

member is inferred to be several tens of meters.

Crinoidal Limestone of Keku Strait

An unnamed crinoidal limestone unit was defined for fossiliferous Carboniferous limestone in Keku Strait by Muffler 

(1967) because it consisted of medium-bedded to massive, 

fossil-fragmental limestone unlike the limestone in Saginaw 

Bay. The crinoidal limestone contains Pennsylvanian foraminifers and fusulinids (see R.C. Douglass, 1969, in Alaska 

Paleontologic Database, http://www.alaskafossil.org/), Early 

and Middle Pennsylvanian conodonts (see A.G. Harris, 1980, 

in Alaska Paleontologic Database, http://www.alaskafossil.

org/), and late Early and Middle Pennsylvanian brachiopods 

(see J.T. Dutro, 1983, in Alaska Paleontologic Database, http://

www.alaskafossil.org/). The crinoidal limestone stratigraphically overlies massive Devonian limestone that does not 

resemble any part of the Devonian section in Saginaw Bay, but 

like the rocks in Saginaw Bay, it represents a shallow-water 

depositional environment that contrasts with the deep-water 

depositional environment represented by correlative bedded 

chert and chert-graywacke beds in the Cannery Formation.
24 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Ladrones Limestone

The Ladrones Limestone (Eberlein and Churkin, 1970), 

mapped north of Sukkwan Island, consists of light-gray, thickbedded to massive, sublithographic limestone containing 

matrix-supported pellets, oolites, foraminifers, fusulinids, shelly 

debris, and light-gray chert nodules. It depositionally overlies the 

Peratrovich Formation and is inferred to be laterally gradational 

to the Klawak Formation, which contains the same fusulinids, 

Fusulinella sp. (Eberlein and Churkin, 1970; Eberlein and others, 

1983; see R.C. Douglass, 1969, in Alaska Paleontologic Database, 

http://www.alaskafossil.org/). The Ladrones Limestone, which 

also contains corals, brachiopods, and conodonts of Early and 

Middle Pennsylvanian age (Eberlein and others, 1983; Savage 

and Barkeley, 1985), represents a shallow-water depositional 

environment that constitutes part of a southern belt of rocks in the 

Alexander terrane, contrasting with the northern belt of chert and 

argillite in the Cannery Formation, that represents a deep-water 

depositional environment.

Klawak Formation

The Klawak Formation (Eberlein and Churkin, 1970), which 

depositionally overlies the Peratrovich Formation near Klawock, 

consists of 150 to 300 m of gray calcareous sandstone and siltstone 

containing matrix-supported chert pebbles, arenaceous limestone, 

and fossil-fragmental limestone. The sandstone beds are graded 

and crossbedded. Limestone of the Klawak Formation contains 

abundant fusulinids, including Fusulina sp., Fusulinella sp., 

Millerella, Nankinella, and Staffella, as well as abundant productid 

brachiopods, solitary and colonial corals, bryozoans, and the trace 

fossil Spirophyton (Churkin and Eberlein, 1975). G.H. Girty (in 

Buddington and Chapin, 1929, p. 116-117) noted that the fossils 

collected from the Saginaw Bay and Klawak units “...have no 

counterpart of any age in the United States,” that Fusulina and 

Fusulinella are known from the Mountain Limestone of Russia, 

and that some species in the Saginaw and Klawak collections 

resemble fossils described from the Gzelian Stage of the Pennsylvanian in Russia. Eberlein and Churkin (1970, p. 59) noted 

that the small size and simple structure of the fusulinids suggest 

a Pennsylvanian rather than a Permian age, and stated that A.K. 

Armstrong considered the brachiopods and corals to be Early 

Pennsylvanian. Limestone of the Klawak Formation also contains 

Early and Middle Pennsylvanian conodonts (Savage and Barkeley, 

1985). The bioclastic limestone and crossbedded sandstone of the 

Klawak Formation indicate shoaling deposition after deposition of 

cherty limestone of the Peratrovich Formation, in contrast to agecorrelative deepwater chert of the Cannery Formation.

Summary of Pennsylvanian Lithostratigraphic 

Units

Pennsylvanian fossils in the Cannery Formation and 

in the Porcupine Creek area occur in radiolarian chert or 

limestone lenses in argillite. All other stratigraphic units in 

the Alexander terrane that contain Pennsylvanian fossils are 

limestone-dominated sections. The chert- and argillite-dominant Pennsylvanian rocks in the Cannery Formation and in the 

Porcupine Creek area, which represent deepwater depositional 

environments, occur only in the northern part of the Alexander 

terrane. In contrast, the limestone-dominant Pennsylvanian 

rocks of the Saginaw Bay, Ladrones, and Klawak Formations, 

which represent shallow-water depositional facies, occur in the 

southern part of the Alexander terrane (fig. 12).

Permian Lithostratigraphic Units in the 

Alexander Terrane

Early Permian lithostratigraphic units in the Alexander 

terrane include the Halleck Formation, an informal argillite 

and slate unit in the William Henry Bay area, and an informal 

volcanic unit in the same area. Several longer-ranging units 

contain early Permian fossils, including the Cannery Formation and the informally named Porcupine Slate of Redman 

and others (1985). The Pybus Formation, which unconformably overlies the Halleck and Cannery Formations, contains 

late early and early late Permian brachiopods and conodonts. 

Except for two localities near William Henry Bay at which 

limestone lenses in chert contain both late early and early late 

Permian fossils (locs. 8, 9, table 2), siliceous and carbonaceous argillite of late Permian age is unknown in the Alexander terrane. The broad distribution of the Pybus Formation 

throughout southeastern Alaska supports the hypothesis of a 

regional unconformity and a regional change from various 

depositional environments in the early Permian to a more 

uniform warm, shallow-marine depositional environment in 

the late Permian.

Halleck Formation 

The early Permian Halleck Formation is correlative 

with the upper part of the Cannery Formation. The Halleck 

Formation, named for rocks in Halleck Harbor on Kuiu Island 

by Muffler (1967), consists of siltstone, sandstone, limestone, 

conglomerate, and mafic volcanic and volcaniclastic rocks 

(figs. 2, 3, 13). The dominant rock type is dark-gray calcareous siltstone that grades to silty fossiliferous limestone. The 

siltstone contains thin beds of tan-weathering fossil-fragmental limestone containing rugose corals (fig. 13A; loc. 44, fig. 2 

and table 1), that grades upward to fossiliferous crossbedded 

calcareous sandstone, volcaniclastic debris flows (fig. 13B), 

and polymictic conglomerate. The sandstone and conglomerate contain clasts of unmetamorphosed mafic volcanic rocks, 

limestone, and chert. Pillow basalt flows (fig. 13C), pillow 

breccia, and volcaniclastic deposits locally are more than 

100 m thick in the middle of the Halleck section. Fossils in 

the sedimentary and volcanic rocks are early Permian and 

Permian (locs. 42-44, fig. 2 and table 1; Muffler, 1967; Brew 

and others, 1984). The Halleck Formation, which is less than 
 Permian Lithostratigraphic Units in the Alexander Terrane 25

200 m thick, conformably overlies the Carboniferous Saginaw Bay Formation and unconformably and disconformably 

underlies the Pybus Formation (fig. 13C; Muffler, 1967). 

The Halleck Formation, which was inferred to represent a 

shallow-water depositional facies to the southwest of the 

Cannery Formation (Muffler, 1967) depositionally overlies 

the shallow-water Mississippian and Pennsylvanian rocks that 

form a belt southwest of deepwater Carboniferous rocks of 

the Cannery Formation. 

Rocks of the William Henry Bay Area

Unnamed argillite and limestone mapped near William 

Henry Bay in the Chilkat Mountains (unit Pal, fig. 2) contain 

early Permian fossils (locs. 8, 9, fig. 2 and tables 1, 2; Lathram 

and others, 1958). The rocks include various discontinuous 

sections, including (1) dark gray phyllite with intervals of 

greenstone, overlain by calcareous graywacke and argillite; 

(2) chert breccia in an argillaceous matrix; (3) as much as 100 

m of brownish-gray fossiliferous limestone; (4) interbedded 

nodular brownish-gray limestone, greenish-brown bedded 

chert, and limestone with chert clasts; and (5) interbedded 

dark-gray limestone, siltstone, calcareous graywacke, argillite, 

and chert-clast calcareous conglomerate. A related section of 

more than 200 m of basalt is mapped separately as unit Pv 

(fig. 2). The stratigraphic order within this unit is undefined. 

Only fault contacts have been observed at the boundaries of 

the unit, which is estimated to be at least 1,000 m thick (Lathram and others, 1958) but may be structurally repeated. The 

rocks extend into the northeast corner of Glacier Bay National 

Park (Brew, 1997). Limestone in this section contains the 

brachiopod Septacamera stupenda Grant that is a hallmark of 

limestone of the Pybus Formation, and a limestone lens in the 

bedded chert section contains late early Permian conodonts, 

including Hindeodus excavatus (Behnken) and Neogondolella 

Figure 13. Bedding and a rugose coral (A) and volcaniclastic rocks (B) from the type locality of the Halleck Formation at Halleck 

Harbor, Saginaw Bay, southeastern Alaska (figs. 1, 2). Limestone of the Pybus Formation overlying pillow basalt of the Halleck Formation 

(C) and fossil hash of the Pybus Formation (D) are from exposures in Saginaw Bay.

C D

A B
26 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

idahoensis (Youngquist, Hawley, and Miller), as well as Septacamera stupenda Grant (locs. 8, 9, fig. 2 and tables 1 and 2; 

see Alaska Paleontologic Database, http://www.alaskafossil.

org/). The age conflict between brachiopods and conodonts 

in this limestone lens needs further study but suggests that 

the unit may include components that are equivalent to the 

Halleck, Cannery, and Pybus Formations. More work is also 

needed to determine the stratigraphic order within the unit. 

The rocks are overlain by a section of dark-gray to black, redweathering chert, siliceous argillite, and graywacke at least 

300 m thick, which is in turn overlain by basalt and agglomerate of inferred Permian or Triassic age (Lathram and others, 

1958). These rocks have not been mapped in detail and may 

include tectonically interleaved components of the Cannery 

and Pybus Formations, the Halleck and Pybus Formations, or 

lateral facies equivalents of those units.

Slate of Porcupine Creek

North of the Chilkat Mountains, in the Porcupine CreekTsirku River area (fig. 2), the Porcupine Slate of Redman and 

others (1985), which consists of black slate and phyllite and 

dark-gray metalimestone, was assigned a Devonian through 

Triassic age by Gilbert and others (1987). The unit includes 

black argillaceous metachert, banded metasiltstone, volcaniclastic metagraywacke, granule to pebble breccia, and a few 

layers of metabasalt that overlie a band of massive metalimestone containing megafossils and conodonts of Devonian and 

Mississippian age. The black slate is sooty to siliceous and 

locally calcareous where it grades to lenses of sooty limestone. 

The calcareous siltstone and sooty metalimestone together 

compose about 25 percent of the unit; the metalimestone layers are as much as several meters thick. Fossils from a poorly 

designated locality in the lower part of the section on Porcupine Creek are Artinskian (late early Permian), include the 

brachiopods Productus cf. P. mammatus and P. gruenwaldi, 

Spirifer cf. S. marconi and S. muskheylensis, and Camarophoria cf. C. margaritovi, and have affinities with brachiopods 

from the Artinsk Sandstone of the Ural Mountains and the 

Russian Platform (loc.1, fig. 2 and table 1; Wright, 1904; see 

G.H. Girty in Eakin, 1919). The same fossils were identified in 

collections from Saginaw, Herring, and Pybus Bays (Wright, 

1906; Eakin, 1919). These fossils, which are unknown from 

the North American Craton, suggest that the Alexander terrane 

was isolated from North America during the Permian. 

 In the lower Porcupine Creek section, gray chert, in beds 

as much as 50 cm thick, with phyllitic partings as much as 

8 cm thick, depositionally overlies thick-bedded to massive 

metalimestone containing corals and Devonian-Mississippian 

conodonts (Gilbert and others, 1987). The chert grades upsection to black cherty, pyritic, sooty and graphitic argillite, 

with lenses of green to black chert and gray metalimestone 

as much as 80 cm thick, which grades up to a more siliceous 

slate containing siliciclastic sandstone beds (Eakin, 1919). The 

cherty argillite composes about 70 percent, the chert about 25 

percent, and the limestone about 5 percent of this part of the 

section (Gilbert and others, 1987). The rocks closely resemble 

rocks east of Kake and in the Duncan Canal area. In the upper 

Porcupine Creek section, mafic sills and indistinctly lumpy 

(pillow?) flows, as much as 10 m thick, that include centimeter-scale lenses of metalimestone compose about 40 percent of 

the section; and black chert, in beds as much as 15 cm thick, 

cherty black argillite, and millimeter- to centimeter-scale 

laminated metalimestone compose 60 percent of the section. 

The top of the section consists of black cherty argillite that 

includes chert beds as much as 10 cm thick, and argillite with 

wispy millimeter-scale starved ripples of siltstone. The section 

is folded, faulted, and discontinuously exposed, so its true 

thickness is unknown, although the band of mafic volcanic 

rocks is discrete and not repeated. 

The cherty argillaceous rocks are overlain by a 

350-m-thick section of pillow basalt, pillow breccia, and 

rhyolite that yielded a Late Triassic U-Pb zircon age of 213±5 

m.y. (Green and Greig, 2004), which provides a minimum age 

for the slate. The pillows are well formed and include interpillow lenses of limestone and volcaniclastic debris. The pillow 

basalt in the Triassic section is associated with mineralized 

calcareous metasedimentary rocks and argillaceous limestone 

that contain volcanogenic massive sulfide deposits (Hawley, 

1976; Still, 1984). Above the mineralized zones is a calcareous 

matrix-supported breccia containing angular blocks of volcanic rocks that resembles calcareous matrix debris flows in the 

Hyd Group on Admiralty Island. Triassic fossils were reported 

from the Glacier Creek area, but no fossil localities were designated (Gilbert and others, 1987; Green and Greig, 2004).

The presence of Permian brachiopods from a poorly 

located limestone layer in lower Porcupine Creek (Eakins, 

1919) suggests either that the belt of massive limestone grades 

from Devonian and Mississippian through Permian with little 

or no Pennsylvanian deposition represented, or that the base of 

the argillite section is early Permian or only slightly older. As 

in the Greens Creek-Eagle Peak area, without fossils the Permian sooty argillite is difficult to distinguish from Triassic sooty 

argillite (Lathram and others, 1960; 1965; Gilbert and others, 

1987), although the thick section of pillow basalt is a reliable 

indicator for the Triassic section in the Porcupine Creek area. 

A basal Triassic conglomerate containing clasts of Paleozoic 

rocks that is common in the Hyd Group elsewhere in the Alexander terrane has not been identified in the Porcupine Creek 

area. The Permian-Triassic boundary may be within the sooty 

argillite, or it may be represented by the base of the massive 

pillow basalt in the Porcupine Creek area.

Correlative Permian Rocks in British Columbia 

on Trend with Porcupine Creek

Carboniferous and Permian rocks mapped by Watson 

(1948) along strike from the Porcupine Slate of Redman and 

others (1985) in British Columbia, Canada, have not been 

mapped in detail and are included in an Ordovician through 
 Permian Lithostratigraphic Units in the Alexander Terrane 27

Triassic unit (Journeay and others, 2000) or in one of the Silurian through Permian units of Mihalynuk and others (1993). 

One such Silurian through Permian unit, SPsa, is a black, 

sooty-weathering argillite with minor thinly laminated limestone interbeds that “may be mistaken for uTrTs” (Mihalynuk 

and others, 1993), a conundrum nearly identical to that of the 

slate of Porcupine Creek and the sooty argillite at Eagle Peak 

on Admiralty Island. Host rocks to the Late Triassic Windy 

Craggy VMS deposit unconformably overlie gray limestone, 

at least 1,000 m thick, containing Devonian fossils and black 

limy argillite containing late Eifelian to early Givetian conodonts (MacIntyre, 1984), and the base of the Triassic section 

consists of black limy argillite and siltstone with thin intercalations of tuff that are lithologically correlated with rocks nearby 

containing Late Triassic (Norian) conodonts (MacIntyre,1983, 

1984; Peter and Scott, 1999). Although the host rocks of the 

Windy Craggy VMS deposit are correlated with the Hyd 

Group that hosts the VMS deposits in the Alexander terrane 

(MacIntyre, 1984, Green and Greig, 2004), Permian and older 

rocks similar to those of the Cannery Formation have not been 

identified near the Windy Craggy VMS deposit.

Pybus Formation

The Pybus Dolomite was named by Loney (1964) for 

fossiliferous cherty dolostone that is well exposed in Pybus 

Bay on Admiralty Island (figs. 2, 14). The abundance of 

limestone in the unit on Kuiu and Kupreanof Islands (fig. 10) 

led Muffler (1967) to rename it the “Pybus Formation”. The 

dolostone is sugary, fine- to medium-grained, and dark-gray 

to pale yellowish-brown on fresh and weathered surfaces. 

Beds, which are as much as 3 m thick, commonly contain 

grayish-blue chert lenses and nodules and silicified fossils (fig. 13D) that typically include several species of the 

distinctive brachiopod Septacamera, in addition to Stenocisma, Neospirifir, Spirifirella, and Anidanthus of Permian 

and early late Permian age (locs. 45, 46, fig. 2 and table 2; 

Loney, 1964). The age of the unit was revised to early Permian on the basis of Kungurian corals (Rowett, 1975) and is 

herein extended to include rocks mapped as limestone of the 

Pybus Formation that contain early late Permian conodonts 

(loc. 47, fig. 2 and table 2) and brachiopods including Septacamera pybensis Grant (loc. 52, fig. 2 and table 2; Grant, 

1971). Conodonts recovered from the Pybus Formation 

include Neogondolella phosphorensis and Xaniognathus of 

late Roadian through early Capitanian (early late Permian) 

age (loc. 47, fig. 2 and table 2), in contrast to the late early 

Permian conodonts species that accompany Septacamera 

stupenda in the William Henry Bay section (locs. 8, 9, fig. 2 

and table 2), which is not mapped as the Pybus Formation. 

Although the contact is not exposed, bedding in the Pybus 

Formation has an angular discordance relative to that of the 

adjacent Cannery Formation in Pybus Bay, so an unconformable contact is inferred (Loney, 1964). The Pybus Formation 

is unconformably overlain by basal breccia of the Hyd Group 

on southern Admiralty Island. A measured section of the 

Pybus Formation in Pybus Bay indicates a thickness of 133 

m (Loney, 1964); the thickness of similar cherty limestone 

was estimated at 137 m on Kuiu Island (Wright and Wright, 

1908) and at 152 m on Kupreanof Island (Muffler, 1967). 

On the southeast shore of Suemez Island (figs. 2, 12), 

a 93-m-thick section of fossiliferous bedded brownish-gray 

limestone containing Permian brachiopods structurally 

underlies Mississippian black bedded chert, argillite, and 

rhythmically bedded black fetid limestone assigned to the 

middle and upper members of the Peratrovich Formation. 

Fossils in the Permian limestone on Suemez Island include 

silicified Globiella? sp. and Septacamera, as well as spiriferid, productid, orthotetacid, and dictyoclostid brachiopods, 

ramose bryozoans, horn corals, and echinoderms that closely 

resemble fossils from the Pybus Formation in Saginaw Bay 

and Pybus Bay (loc. 53, fig. 2 and table 2; Buddington and 

Chapin, 1929). The Permian limestone on Suemez Island is 

herein assigned to the Pybus Formation.

White limestone and dolostone on Kupreanof and Kuiu 

Islands (fig. 2) include light-gray and blue beds, lenses, nodules, and fragments of chert, similar to that of dolostone in the 

Pybus Formation, and contain fossils assigned by G.H. Girty 

to the Permian, that are correlated with fossils from the Artinsk Sandstone of the Ural Mountains in Russia (Buddington 

and Chapin, 1929). The limestone on Kuiu Island unconformably or disconformably overlies shallow-water silty limestone 

of the early Permian Halleck Formation in Saginaw Bay and 

unconformably overlies chert of the Cannery Formation on 

Kupreanof Island (Muffler, 1967). This relation was inferred 

to represent a “collision and amalgamation of two unlike 

tectonostratigraphic terranes in latest early Permian time as 

postulated by Berg, Jones, and Coney (1978)” (Jones and others, 1981). Muffler (1967) suggested that the lithologic differences between chert of inferred Permian age (now known 

to be Devonian and Mississippian) in the Cannery Formation 

near Kake and in the Permian silty limestone in Saginaw Bay, 

which are both overlain by the Pybus Formation, was due 

to Permian shortening of depositional facies which predated 

deposition of the Pybus Formation. New fossil information 

(locs. 33, 34, fig. 2 and table 2; Karl and others, 1999; see 

Alaska Paleontologic Database, http://www.alaskafossil.org/) 

indicates that the early Permian silty limestone of the Halleck 

Formation in Saginaw Bay contrasts with the early Permian 

chert and siliceous argillite and silty limestone of the Cannery Formation west of Duncan Canal on Kupreanof Island, 

in support of the interpretation by Muffler (1967). Differences 

between the Devonian rocks beneath the Cannery Formation 

on northern and southern Admiralty Island, and between the 

rocks beneath the Cannery Formation on southern Admiralty 

and Kupreanof Islands, as discussed above, suggest that 

collision and amalgamation of two or more contrasting arcs 

occurred during deposition of rocks of the Cannery Formation 

now exposed on Admiralty Island. The Permian metamorphic 

belt on Admiralty Island, which may include the undated 

metamorphic rocks on northern Kupreanof Island (figs. 2, 15), 
28 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

0 10 20 30 40 km

North

45

Pybus Formation

EXPLANATION

Fossil locality 

(table 2)

Admiralty Island

Chichagof Island

William Henry Bay

Saginaw Bay

Halleck Harbor

Keku Strait

Snug Cove

Pybus Bay Cannery Cove

Kupreanof Island

Kake

Chatham

 Strait

Glacier Bay

Kuiu Island

Juneau

8 9

45

46

47

48

51 50

52

Figure 14. Southeastern Alaska, showing distribution of the late Permian Pybus Formation and age-equivalent rocks in the Alexander 

terrane (figs. 1, 2). 

supports the interpretation of a collision-related deformation 

event. The Permian deformation postulated by Muffler (1967) 

is also supported by the regional unconformity beneath the 

Pybus Formation throughout the Alexander terrane. The 

contrast in sedimentary facies and deformation between early 

Permian rocks of the Cannery Formation and the Halleck 

Formation across Keku Strait may represent a sedimentary 

facies change and shortening of a single arc, or may reflect 

a Permian juxtaposition of arcs or a “terrane” amalgamation 

boundary, as suggested by Berg and others (1978). The contrast in basement rock types beneath the Cannery Formation 

and the Halleck Formation supports the hypothesis of Berg 

and others (1978).

Discussion

Rocks in Pybus Bay and Keku Strait that were originally 

included in the Cannery Formation on the basis of similar 

lithology (Muffler, 1967) are not identical, although both 

areas include bedded chert; however, the cherts in the two 

areas differ in age. The ages reported by Jones and others 

(1981) from Keku Strait were used to revise the age of a 

unit containing Permian fossils in its type area in Pybus Bay 

to a unit with a Devonian and Mississippian age. This age 

reassignment for the Cannery Formation ignored the rock 

types and fossils in the type area, as well as the concept of 

using a well-documented type section of a formation as a 

standard of comparison for both age and lithology. By Jones 

and others’ redefinition, the rocks of Cannery Cove are 

excluded from the Cannery Formation. The rocks at Kake that 

contain Devonian fossils do not resemble the rocks in Cannery 

Cove in either age or lithology. The graywacke-chert couplets 

that compose the turbidites at Cannery Cove are distinctive 

and have not been described in the vicinity of Kake. East of 

Kake, bedded chert and graywacke-argillite turbidites are 

mapped as the Cannery Formation (Muffler, 1967; Brew and 

others, 1984; Karl and others, 1999), and these cherts have 

yielded radiolarians of Mississippian through Permian age. 

Graywacke-chert turbidites, which have been described only at 

Pybus Bay and Windfall Harbor, contain Mississippian(?) and 

Mississippian through Permian radiolarians. 

All chert in the Alexander terrane need not be assigned 

to the Cannery Formation. Black bedded chert that contains 

rare lenses of Late Devonian limestone has been described at 

Kake and in Hawk Inlet. On the basis of both lithology and 

age, the chert at Kake might reasonably be correlated with the 

chert in Hawk Inlet. The black chert at Saginaw Bay, which is 
 Discussion 29

interbedded with Devonian limestone, does not resemble the 

chert at Kake or in Hawk Inlet in either aspect or context. 

As described above, the chert in Hawk Inlet was originally assigned to the Retreat Group by Lathram and others 

(1965) and later by Brew and Ford (1985) to their unit Mzps. 

The rocks at Point Retreat on Admiralty Island, the type locality for the Retreat Group, include greenschist and quartzite 

intruded by quartz diorite that yielded concordant Neoproterozoic U-Pb ages of 545–547 Ma (Karl and others, 2006). The 

chert in Hawk Inlet, which contains Late Devonian fossils, 

does not resemble the rocks at Point Retreat, so it should not 

be included in the Retreat Group or the Mesozoic unit of Brew 

and Ford (1985). Black chert with limestone lenses is absent 

in Cannery Cove: the chert in Hawk Inlet does not correlate 

with the rocks in Cannery Cove in either age or lithology, nor 

in degree of deformation or metamorphic grade. Although 

the chert in Hawk Inlet is similar in both age and lithology to 

chert assigned to the Cannery Formation at Kake, it cannot 

unequivocally be assigned to the Cannery Formation because 

it is significantly more deformed and metamorphosed than the 

Figure 15. 40Ar/39Ar age spectra for minerals dated from metamorphic rocks on Admiralty Island, southeastern Alaska (figs. 1, 2;

 table 3), showing pervasiveness of the Permian thermal event that disturbed argon systematics in minerals.

Permian argillite assigned to the Cannery Formation in Hawk 

Inlet and dated nearby at Eagle Peak. The Cannery Formation can reasonably be extended to be a Mississippian through 

Permian unit on the basis of distinctive rock types and fossils 

in both Cannery Cove and Windfall Harbor and the relatively 

continuous outcrops of similar rock types between the two 

areas, as well as between occurrences of Mississippian and 

Permian chert, graywacke, and argillite on Kupreanof Island. 

Because a boundary between Devonian and Mississippian 

chert on Kupreanof Island is difficult to map, the simplest 

solution to this problem is to extend the age of the Cannery Formation to Late Devonian through early Permian. 

However, the base of the Cannery Formation appears to be a 

time-transgressive boundary. Black chert and argillite associated with limestone containing Silurian-Devonian conodonts 

in the Hood Bay Formation near Cannery Cove contributes 

distinctive clasts of deformed black chert with quartz veinlets 

to sandstone and conglomerate of the Cannery Formation 

on Admiralty Island. The absence of the deformation and 

metamorphism of the Hood Bay Formation and the chert of 

93PH127B WM

93PH143 WM

97PH045B WM

97PH055B HO

91SK168A WM

96SK013A WM

273-260-Ma thermal event

400

360

320

280

240

200

160

120

80

40

0

0 0.2 0.4 0.6 0.8 1.0

AGE, IN MILLIONS OF YEARS

FRACTION OF 39Ar RELEASED
30 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Hawk Inlet in the Cannery Formation on Admiralty Island 

indicates a post-Devonian, pre-Cannery deformation event on 

Admiralty Island.

The Cannery Formation overlies a post-Devonian 

unconformity on Admiralty Island but apparently was deposited continuously from Devonian through early Permian 

time on Kupreanof Island. The simplest way to explain these 

observations is to consider the Cannery Formation to be a 

time-transgressive unit that is oldest near Kake and younger to 

the northeast in Duncan Canal and on Admiralty Island. Late 

Devonian chert-bearing units, including the chert in Hawk 

Inlet and the chert member of the Saginaw Bay Formation, 

have separate depositional, metamorphic, and deformational 

histories and could have been juxtaposed against the stratigraphic section that includes the Cannery Formation at different times. Judging from chert clasts in clastic strata of the 

Cannery Formation, rocks of the Hood Bay Formation were 

deposited adjacent to, and contributing to the Cannery Formation during post-Devonian, and no later than early Permian 

time. If the metamorphic event that resulted in early Permian 

mineral cooling ages for the metamorphic rocks on northern 

Admiralty Island is the same event that affected the metamorphosed chert in Hawk Inlet, then the chert in Hawk Inlet was 

juxtaposed with rocks of the Cannery Formation after the early 

Permian. Conglomerate of the early Permian Halleck Formation contains clasts of chert that could have been derived from 

the Cannery Formation at Kake or the Saginaw Bay Formation on Kuiu Island, suggesting an early Permian deformation event to Muffler (1967) and Jones and others (1981). 

Both the Halleck Formation and the Cannery Formation are 

unconformably overlain by the late early to early late Permian 

Pybus Formation, so apparently both the rocks that include 

the Saginaw Bay Formation and the rocks that include the 

Cannery Formation were juxtaposed before deposition of the 

Pybus Formation.

Because chert pebbles in conglomerate of the early Permian Halleck Formation contain Mississippian and Devonian 

radiolarians, Jones and others (1981) chose to restrict the age 

of the Cannery Formation to Mississippian and Devonian in 

order to constrain chert of the Cannery Formation as a clastic 

source for early Permian conglomerate of the Halleck Formation and signal a collision between the rocks on Kupreanof 

Island and the rocks on Kuiu Island (fig. 2). Such an age 

restriction is unnecessary if the uplift was transgressive. 

Alternatively, Mississippian and Devonian chert clasts in the 

Halleck Formation could have been derived from the Saginaw 

Bay Formation. Rather than revise the age of the Cannery Formation to Mississippian and Devonian and ignore the Permian 

fossils at the type locality, Jones and others (1981) could also 

have (1) correlated the chert at Kake with coeval chert in the 

Saginaw Bay Formation or (2) redefined the Cannery Formation as Devonian through Permian. 

The simplest solution to this stratigraphic problem is to 

include both the Late Devonian through Permian chert section 

on Kupreanof Island and the Mississippian through Permian 

graywacke, chert, argillite, and carbonate exposed at the type 

locality on Admiralty Island in the Cannery Formation. We 

suggest assigning the chert at Kake to a black chert member 

of Late Devonian age in the Cannery Formation so that it can 

be independently correlated with other Late Devonian cherts. 

Accordingly, we propose an informal lower chert member of 

Devonian age, a middle chert-graywacke member of Mississippian to Permian age, and an upper argillite-chert member of 

Permian age.

Rocks assigned to the Cannery Formation in this report 

thus contain fossils as old as Famennian, or Late Devonian, and as young as early late Permian, extending from 

approximately 374 to 260 Ma, according to the time scales of 

Gradstein and others (2004), Walker and Geissman (2009). 

Approximately 134 m.y. is an unusually long period of time 

for continuity of a lithostratigraphic unit that reflects a particular depositional environment. The Cannery Formation includes 

various sedimentary and volcanic rock types that indicate 

intermittent tectonic activity, but is dominated by chert and 

argillite that indicate slow sedimentation in a stable environment over a large area.

Implications of Early Permian 

Sedimentary Facies in the Alexander 

Terrane

Early Permian sedimentary and volcanic rocks are 

widespread in the Alexander terrane (figs. 2, 16). They are 

commonly fossiliferous, and only marine lithofacies have 

been recognized. The volcanic rocks are entirely mafic, with 

trace- and rare-earth-element signatures that indicate various 

ocean-floor to volcanic-arc affinities on various geochemicaldiscriminant diagrams (fig. 8). After restoration of 180 km of 

dextral offset on the Chatham Strait Fault on the basis of the 

criteria of Hudson and others (1981), a review of the distribution of shallow-water and deepwater depositional facies 

for early Permian rocks in the Alexander terrane shown in 

figure 16, though somewhat disrupted by folding and faulting, 

indicates a distribution of rock types that resolves into regional 

northwesterly striking trends of early Permian intrusive rocks, 

Permian mafic volcanic and volcaniclastic rocks, and five 

lithofacies that represent early Permian sedimentary rocks. 

The five early Permian sedimentary lithofacies shown in figure 

2 include (1) fossiliferous bedded limestone (PMl), (2) silty 

limestone and calcareous siltstone (Phl), (3) sooty carbonaceous siltstone, chert, and limestone (Pal), (4) graywackechert turbidites and argillite-matrix debris flows (PDca), and 

(5) chert and siliceous claystone (PDc). Bedded fossiliferous 

limestone and bioclastic limestone represent shallow-water 

bioherms and their talus aprons that are interbedded with 

volcanic rocks in Halleck Harbor and the Chilkat Mountains 

(fig. 2). Fossiliferous silty limestone, calcareous siltstone, 

and calcarenite also represent shallow-water deposits. Carbonaceous argillite and gray chert represent zones of either (1) 
 Implications of Early Permian Sedimentary Facies in the Alexander Terrane 31

upwelling and high biologic productivity along slopes below 

the carbonate compensation depth or (2) restricted basins. 

Graywacke turbidites and debris flows may represent slope 

basins, arc basins, rift basins, or submarine-canyon and trench 

facies deposits (Mutti and Ricchi-Lucchi, 1972). Light-gray to 

red siliceous claystone represents well-oxygenated deepwater 

deposits (Bostrom, 1976). 

The early Permian depositional facies shown in figure 16 

indicate that siliceous deepwater sedimentary rocks lie to the 

north of calcareous shallow-water rocks. The early Permian 

shallow-water sedimentary rocks mostly lie to the north of the 

early Permian intrusive rocks. This spatial relation of lithofacies and igneous rocks suggests that the inferred Permian arc 

was facing northeastward. Local anastomosing shear, boudinage, and blocks-in-matrix textures, such as those observed 

Permian mafic volcanic rocks

Permian Halleck Formation

Permian argillite and limestone

Mississippian through Permian limestone

Devonian through Permian Cannery Formation, argillaceous

Devonian through Permian Cannery Formation, chert dominant

Paleozoic metamorphic rocks with Permian Ar-Ar ages

Permian intrusive rocks

Inferred Permian thrust fault, shown schematically

Pi

PMl

Pal

PDc

Pv

Phl

PDca

Pzm

EXPLANATION

Chatham Strait Fault (restored 180 km)

Ketchikan

Craig

Suemez 

Island

Prince of Wales Island

Klawock

Sukkwan Island

Zarembo Island

Petersburg

Kake Towers Arm

Duncan Canal

Chatham

 Strait

Sitka

Chichagof Island

Glacier Bay

William

Henry Bay

Pybus Bay

Cannery Cove

Mount Henry Clay

Porcupine Creek

Juneau

Hawk Inlet Eagle Peak

Windfall Harbor

Saginaw Bay

Halleck

Donkey Bay

U.S. Canada

Klehini River

Tsirku River

Harbor

Gambier Bay

Snug Cove

Greens Creek

Kuiu Island Clarence

Strait

Southern arc

Northern arc

0 25 50 75 100 km

North

Kupreanof 

Island 

Keku Strait

Admiralty Island

Figure 16. Southeastern Alaska, showing distribution of Permian sedimentary, metamorphic, and igneous rocks and inferred model for 

their tectonic setting (figs. 1, 2).

in the deepwater sedimentary facies at Snug Cove, Towers 

Arm, and Zarembo Island, are inferred to reflect accretionary 

processes at an arc margin or, possibly, an accretionary zone 

between two or more arc fragments and are consistent with a 

northeast-facing early Permian arc on the southern Alexander 

terrane. Ductile structures in metamorphic rocks on Admiralty Island are dated by early Permian metamorphic-mineral ages (figs. 2, 4C, 11; table 3; appendix) and are structurally juxtaposed with the early Permian accretionary-complex 

rocks suggest a lower-plate structural position for the rocks 

in the northern Alexander terrane. Stratigraphic differences 

between Paleozoic protoliths of metamorphosed rocks of the 

northern Alexander terrane and unmetamorphosed Paleozoic 

rocks of the southern Alexander terrane were previously recognized, and these areas were referred to as the Admiralty and 
32 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Craig subterranes, respectively (Berg and others, 1978). The 

early Permian metamorphic-mineral ages support juxtaposition of these separate stratigraphic sequences during the early 

Permian, as proposed by Muffler (1967) and Jones and others 

(1981). The distribution of early Permian sedimentary facies, 

deformation textures, metamorphic rocks, and intermediatecomposition intrusive rocks in southeastern Alaska described 

above is compatible with an early Permian collision of two (or 

more) Paleozoic arcs that are now components of the Alexander terrane.

Although it contains fossils as old as latest early Permian, 

for simplicity the Pybus Formation is shown only on the late 

Permian map (fig. 14), because it overlies the huge diversity of 

older rocks in the Alexander terrane, provides a minimum age 

for a regional unconformity, and represents a discrete regional 

time horizon. 

Early Permian Metamorphic Rocks

Metamorphic rocks on Admiralty Island include the 

Retreat Group, the Gambier Bay and Hood Bay Formations, 

and informally named greenschist-facies metasedimentary 

and metavolcanic rocks. The Retreat Group consists of schist 

and gneiss intruded by Neoproterozoic plutons (Karl and 

others, 2006). The Gambier Bay Formation consists mostly 

of semischistose to massive greenstone and marble that have 

Devonian protoliths (Loney, 1964; Lathram and others, 1965). 

Mineral assemblages include quartz-muscovite-chlorite-albite, 

quartz-talc-calcite, talc-dolomite, and chlorite-epidote-calcite, 

but the presence of relict pyroxene, hornblende, and calcic 

plagioclase indicates that metamorphic equilibrium was 

not achieved (Loney, 1964). Chlorite-epidote-calcite schist 

and phyllite are the most abundant rock types, commonly 

containing euhedral pyroxene as much as 2 mm long, and 

less commonly, hornblende. Relict primary augite grains 

with overgrowths of blue sodic amphibole that also grows 

across the foliation of the greenschist-facies minerals (Loney, 

1964, p. 16) suggests that low-temperature, high-pressure 

metamorphism succeeded greenschist-facies metamorphism. 

The metamorphic rocks have northeast vergent ductile 

stuctures. Locally, reduction in the size of pyroxene and augite 

grains and milling of the greenschist-facies minerals into 

phyllonite and mylonite led Loney (1964) to infer subsequent 

low temperature-deformation. 

The Hood Bay Formation consists of Ordovician through 

Devonian black siliceous argillite and chert, with subordinate 

graywacke, limestone, and volcanic rocks (Loney, 1964; 

Carter, 1977). Rocks of the Hood Bay Formation contain 

secondary chlorite, pyrite, quartz veins, and conodonts with 

a color-alteration index (CAI) of 5 (A.G. Harris, written 

commun., 1995), which corresponds to recrystallization 

temperatures of 300-480°C (Epstein and others, 1977; 

Königshof, 2003), a range consistent with greenschist-facies 

metamorphism (Miyashiro, 1973). The Gambier Bay and 

Hood Bay Formations unconformably underlie, and locally 

are faulted against, or thrust over, the Cannery Formation. 

Metamorphic rocks similar to those on Admiralty Island are 

faulted over and against rocks of the Cannery Formation on 

northern Kupreanof Island (Karl and others, 1999).

Informally named metasedimentary and metavolcanic 

rocks mapped north of the Gambier Bay Formation on Admiralty Island contain white mica that yielded consistent early 

Permian 40Ar/39Ar cooling ages (fig. 15; table 3; appendix). 

These ages are broadly distributed between 273 and 260 Ma, 

date northeast vergent ductile deformation, and record a 

regional metamorphic event. Rocks in the Cannery Formation 

contain secondary chlorite (figs. 5A, 5B) but not secondary 

white mica. Clasts of deformed and veined chert similar to that 

of the Hood Bay Formation in sandstone of the Cannery 

Formation in Pybus Bay, and blocks of Devonian marble and 

greenstone similar to that of the Gambier Bay Formation in 

argillite of the Cannery Formation in Snug Cove, lead us to 

conclude that early Permian deformation resulted in greenschist-, and, locally, possible blueschist-facies metamorphism 

of Devonian and older rocks on Admiralty Island and that 

these deformed rocks were uplifted and incorporated into early 

Permian parts of the Cannery Formation by tectonic and 

sedimentary processes. Stratigraphic-layer compositions, 

sedimentary facies, and textures of Permian rocks, as well as 

metamorphic ages, grades, and low-temperature-deformation 

features of these rocks, are consistent with accretionary-complex deposition and deformation during collision of separate 

Paleozoic arcs during the early Permian. 

Deformation that placed the higher-grade greenschistfacies metamorphic rocks on Admiralty Island over the lowergrade Cannery Formation is inferred to be Mesozoic, related to 

regional shortening of the Alexander terrane during collision 

with other terranes and North America (Karl and others, 1998; 

Haeussler and others, 1999). 

Early Permian Intrusive Rocks 

Early Permian calc-alkaline and alkaline intrusive rocks 

were emplaced in the southern part Alexander terrane (figs. 2, 17) 

on Prince of Wales and Sukkwan Islands. These unmetamorphosed plutons intrude Ordovician and Silurian volcanic and 

sedimentary rocks and have biotite and hornblende K-Ar and 

Ar-Ar ages ranging from 278 to 293 Ma (table 3; Eberlein and 

others, 1983). The early Permian plutons have gabbroic to 

syenitic compositions that are inferred to represent arc magmatism, but are relatively alkaline in comparison with typical 

arc magmas above subducting oceanic crust, as described by 

Gill (1981) and summarized by Pearce and Peat (1995) and 

Kelemen and others (2003). These Permian intrusive rocks 

have high K2

O and Na2O contents (table 4), and a diagram 

of immobile trace elements, on which Zr/TiO2 ratio serves 

as a fractionation index and Nb/Y ratio as an alkalinity index 

(fig. 17A; Winchester and Floyd, 1977), demonstrates their 
 Early Permian Intrusive Rocks 33

Sample no. CDZ3 91SK020A 91SK040A 91SK047 01SK128A

Lab no. D385846 D385886 D385843 D385845 C192561

Latitude 55.872 55.882 55.803 55.723 55.542

Longitude -132.618 -132.817 -132.502 -132.547 -133.097

Quadrangle Craig

Rock unit Pi

Rock type quartz

monzonite granodiorite gabbro syenite

Data file Ur37 Ur39 Ur37 Ur37 MRP-03411

SiO2 56.600 63.900 63.600 49.800 62.4

Al2O3 17.400 16.700 18.600 16.800 16.0

FeTO3 7.170 3.450 2.790 10.500 0.76

MgO 2.630 2.160 0.480 3.750 0.41

CaO 5.490 4.660 1.610 7.080 5.17

Na2O 4.520 5.100 6.400 4.710 5.53

K2O 3.270 2.290 4.870 2.040 4.93

TiO2 0.750 0.370 0.280 1.860 0.44

P2O5 0.370 0.140 0.110 1.520 0.20

MnO 0.120 0.060 0.050 0.190 0.04

LOI 0.940 0.390 0.320 0.900 3.32

Total 99.26 99.22 99.11 98.95 99.20

Rb 58.000 41.000 68.000 40.000 88

Sr 630.000 920.000 530.000 990.000 533

Cs 0.392 0.193 0.299 0.869 0.10

Ba 860.000 720.000 840.000 550.000 746

Th 3.720 4.760 26.900 9.060 31.30

U 3.170 1.990 5.780 2.650 10.10

La 23.400 18.800 106.000 78.000 114.00

Ce 50.700 36.500 168.000 176.000 196.00

Nd 24.800 14.800 40.700 72.600 50.60

Sm 5.550 2.800 5.150 11.500 7.58

Eu 1.360 0.760 1.250 3.280 1.04

Gd 4.490 2.110 3.360 9.630 6.80

Tb 0.766 0.284 0.442 1.270 0.92

Ho 1.40

Tm 0.454 0.170 0.73

Table 4. Chemical analyses of Permian intrusive rocks in the Alexander terrane, southeastern Alaska.

Sample no. CDZ3 91SK020A 91SK040A 91SK047 01SK128A

Lab no. D385846 D385886 D385843 D385845 C192561

Latitude 55.872 55.882 55.803 55.723 55.542

Longitude -132.618 -132.817 -132.502 -132.547 -133.097

Quadrangle Craig

Rock unit Pi

Rock type quartz

monzonite granodiorite gabbro syenite

Yb 2.810 1.080 2.240 3.290 4.83

Lu 0.411 0.167 0.362 0.455 0.84

Zr 146.000 124.000 465.000 335.000 590

Hf 3.660 2.940 9.670 6.130 12.50

Ta 0.465 0.440 2.360 4.130 9.77

W <5

Sc 12.500 7.050 1.630 11.700 2.36

Cr 20.000 62.000 20.000 20.000 <3

Co 14.500 10.500 2.630 20.600 0.57

Ni 23.000 25.000 10.000 10.000 3

Zn 57.000 28.000 26.000 83.000 64

As 1.35

Sb 0.793 0.132 0.044 0.090 1.73

Au(ppb) 0.55

Ag <1

Bi <5

Br <1

Cd <1

Cu 29.000 10.000 10.000 20.000 3

Ga 21

Ge <2

Mo 11

Nb 12.000 10.000 40.000 66.000 136

Pb 9

Se <1

Sn 4

V 18

Y 28.000 10.000 18.000 28.000 35
34 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Figure 17. Compositional diagrams showing geochemical affinities 

of Permian intrusive rocks of the Alexander terrane, southeastern 

Alaska (figs. 1, 2), on the basis of limited data (table 4). From 

Winchester and Floyd (1977). A, Zr/TiO2

 ratio serves as a fractionation 

index, Nb/Y ratio as an alkalinity index. From Pearce and others 

(1984). B, Ta versus Yb contents separate extension-related rocks 

from arc rocks. From Whalen and others (1987). C, in diagram Zr-Ga/

Al ratio corroborates within-plate magmatism indicated in figure 17B. 

Element contents are plotted in parts per million.

alkalinity. Incompatible high-field-strength elements (HFSEs), 

such as Zr, Y, Nb, Yb, Ga, and Ta, are immobile during 

hydrothermal alteration and metamorphism up to middleamphibolite grade (Pearce and Norry, 1979; Pearce, 1982; 

Pearce and others, 1984; Pearce and Peat, 1995). The Ta/

Yb ratio is unaffected by partial melting and crystal fractionation, and correlates well with the proportion of terrigenous 

subduction component in a magma (McDermott and others, 

1993; Pearce and Peate, 1995). On the diagram of Pearce and 

others (1984), the Permian intrusive rocks in the Alexander 

terrane show a range Ta/Yb ratios that fall in arc and withinplate fields, indicating that these rocks were not derived from 

simple subduction of oceanic crust beneath the Alexander arc. 

These ratios could result from an arc-arc collision, involvement of an evolved arc source, or involvement of some other 

non-mid-ocean-ridge basaltic (MORB) source (fig. 17B). A 

modern analog for the Permian intrusive rocks of the southern 

Alexander terrane could be the New Hebrides arc. Within 2 

m.y. of the collision of the Entrecasteaux edifice (of uncertain 

plateau or arc composition), the chemistry of magma produced 

in the part of the New Hebrides arc above this specific collision changed to more alkalic compositions, and Sr-, Nd-, and 

Pb-isotopic ratios in the youngest magmas changed to reflect 

more evolved magma sources with respect to the parts of the 

New Hebrides arc that overlie subduction of normal oceanic 

crust and has tholeiitic chemistry and primitive isotopic signatures (Laport and others, 1998). A 2 m.y. period is finer than 

the resolution of the methods used to date the Permian intrusive rocks in the southern Alexander terrane, but the compositional variation in these plutons of similar age plotted in figure 

17B may reflect differences in subducted-crustal compositions 

during the collision of the Admiralty (northern Alexander) and 

Craig (southern Alexander) arcs during the Permian, similar to 

what has been observed in the modern New Hebrides arc.

The Zr-Ga/Al diagram of Whalen and others (1987) 

serves to reinforce the A-type granitic chemistry of the syenite 

from Klawock (fig. 17C), which is the only sample that has 

Ga data. This syenite is K-feldspar porphyritic, and some of 

the phenocrysts have sodic plagioclase rims, a rapakivi texture 

that is typical of A-type granitic rocks (Dall’Agnol and Carvalho de Oliveira, 2007). Biotite needles are finely disseminated in the groundmass, and mafic minerals compose less 

than 5 volume percent of the rock. The syenite contains little 

1

0.1

0.01

0.001

100

10

1

0.1

1000

100

10

1

0.01 0.1

Nb/Y

Yb ppm

10,000*Ga/Al

Zr/TiO2 Ta ppm Zr ppm

11 0

0.11 10 100

11 0

Rhyolite

Comendite/

Pantellerite

Phonolite

Rhyolite

Trachyandesite

Basanite/

Nephelinite

Pi

Alkali

Basalt

Andesite

Andesite/Basalt

Subalkaline Basalt

Within-plate

(A-type)

Syncollisional

(S-type)

I S-types

Volcanic arc

(I-type)

A-type

Ocean ridge

(OR-type)

Rhyodactite/Dactite

Pi

Pi

Within-plate and

anomalous ocean ridge

A

B

C
 Acknowledgments 35

or no quartz and has accessory sphene and apatite. The syenite 

grades to sodic diorite, which contains as much as 15 volume 

percent mafic minerals, including hornblende and aegerine 

augite (Eberlein and others, 1983). Enrichment in highly 

charged cations like Zr and Ga (fig. 17C) cannot be produced 

by differentiation alone, and so this distinctive chemistry is 

inferred to reflect partial melting of anhydrous sources that are 

enriched in F, which forms stable complexes with Zr and Ga, 

while Al is trapped in plagioclase (Whalen and others, 1987). 

Whalen and others (1987) concluded that A-type granite suites 

exhibit considerable variation in chemical composition and 

grade toward I- and S-type granitic compositions, owing to 

heterogeneous primary sources, varying amounts of extraction of earlier melt phases, and(or) tectonic juxtaposition or 

interleaving of diverse terranes. Compositional diversity is 

reflected in figure 17A–C for the Permian intrusive rocks of 

the Alexander terrane. Whalen and others (1987) inferred that 

such depleted magma sources are most common in reactivated 

orogenic belts, an interpretation compatible with such a longlived, evolved, composite arc as the Craig subterrane/southern 

Alexander arc of the Alexander terrane. 

Summary and Conclusions

A review of the rocks and fossils assigned to the Cannery 

Formation in southeastern Alaska indicates that revisions to the 

unit in 1981 excluded rocks of the type area from the unit. A 

simple solution to this problem is to extend the age range of the 

Cannery Formation to include rocks of similar age and lithology to those in the type area. Devonian cherty rocks in the Keku 

Strait area that are only grossly similar in lithology by virtue 

of the fact they include bedded chert, but differ significantly in 

age, might better be recognized as an independent unit but are 

locally difficult to distinguish from other rocks in the Cannery 

Formation without fossil ages. Assigning all the cherty rocks 

in the Alexander terrane to the Cannery Formation is unreasonable, and where cherts are distinguishable as independent units, 

such as the chert in Hawk Inlet, the Saginaw Bay Formation, 

and the Iyoukeen and Peratrovich Formations, they should be 

assigned to appropriate units. The apparently gradational boundary between Devonian and Permian cherty rocks on Kupreanof 

Island presents a problem that is most easily solved with a longranging, Late Devonian through early Permian lithostratigraphic 

unit, and by distinguishing the Devonian chert as a lower member of the Cannery Formation.

Although early Permian rocks appear to gradationally overlie 

Devonian through Pennsylvanian rocks on Kupreanof Island, 

they do not on Admiralty Island, where an unconformity occurs 

between Devonian rocks and Carboniferous and early Permian 

rocks. On Admiralty Island, the Devonian rocks of the Gambier 

and Hood Bay Formations do not lithologically resemble rocks 

of the Cannery Formation, and these rocks, as well as the Devonian cherty rocks in Hawk Inlet (in which protoliths do resemble 

rocks of the Cannery Formation), are significantly more deformed 

and metamorphosed than rocks assigned to the Cannery Formation. The Cannery Formation thus apparently includes a regional 

Carboniferous or early Permian unconformity, expressed through 

clast compositions in the conglomerates on Admiralty Island, on 

Kupreanof Island, and in Keku Strait, that records a deformation 

event within its more regional depositional history. This conclusion has significant implications for the tectonic history of the 

Alexander terrane. Early Permian metamorphic and igneous ages 

for other rocks of the Alexander terrane support the interpretation 

that the unconformity reflects an early Permian orogenic event, 

which variously, and, possibly, transgressively affected different 

components of the Alexander terrane. 

Early Permian rocks form northwest-trending belts in 

the Alexander terrane, indicating that deepwater, open-marine 

depositional facies lie to the north and east and shallow-water 

facies rocks lie to the southwest. Metamorphic rocks with 

early Permian mineral-cooling ages also lie to the northeast of 

the shallow-water-facies rocks. Early Permian intermediatecomposition intrusive rocks inferred to represent the roots of a 

magmatic arc lie to the south of early Permian shallow-water 

sedimentary and volcanic rocks, suggesting that the southern part 

of the Alexander terrane was a north-facing (present coordinates) 

arc during the early Permian. Early Permian metamorphic ages 

for the rocks on Admiralty Island in the northern Alexander 

terrane record ductile northeast vergent deformation and indicate 

crustal thickening in this area, possibly due to a collision of 

pre-Permian arcs. Differences in the pre-Permian stratigraphy 

on Admiralty and Kupreanof Islands with respect to rocks of the 

southwestern part of the Alexander terrane on Chichagof, Kuiu, 

and Prince of Wales Islands suggest an early Permian collision 

of separate oceanic arcs that have previously been referred to 

as the Admiralty (northern) and Craig (southern) subterranes. 

Late early to early late Permian conglomeratic carbonate rocks, 

including the Pybus Formation, that represent shallow-water 

depositional facies are ubiquitous throughout the northern and 

southern components of the Alexander terrane, do not form a 

northwest-striking belt, and may reflect regional uplift following 

collision of the two (or more?) components of the Alexander 

terrane. Permian fossilsinthe Pybus Formation and correlative 

limestone in the Alexander terrane have Uralian rather than 

North American affinities (G.H. Girty, in Wright, 1904, Eakin, 

1919, and Buddington and Chapin, 1929; Grant, 1971), 

suggesting that the Alexander composite arc remained isolated 

from North America until after the Permian.

Acknowledgments 

We thank Keith Labay of the U.S. Geological Survey for 

his assistance with map graphics, Ken Helmold of the Alaska 

Division of Oil and Gas for his assistance with photomicrographs, Julie Dumoulin of the U.S. Geological Survey and 

Cathy Connor of the University of Alaska Southeast for their 

constructive and helpful reviews of the manuscript, and Robert 

Blodgett for geologic-names review. 
36 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

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Appendix
42 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Sample: 93PH143C, UAF sample number: UAF061-05

Weighted average of J from standards = 0.007069 +/- 0.000014

mineral analyzed: white mica

Laser 

Power

(mWatt)

Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured

% Atmospheric 40Ar Ca/K Cl/K 40*/39K Age

(Ma)

+/-

(Ma)

100 0.0015 38.629 0.292 0.146 112.09 0.292

not

available

-4.668 -60.5312 241.2301

200 0.0116 10.522 1.509 0.022 60.913 1.511 4.105 51.6107 41.2993

400 0.1146 10.559 0.309 0.004 10.193 0.309 9.459 116.7672 2.6832

500 0.4099 19.501 0.016 0.003 4.883 0.016 18.521 221.971 2.7658

600 0.4768 19.701 0.011 0.003 4.46 0.011 18.795 225.056 4.3087

700 0.5118 15.889 0.025 -0.004 -7.304 0.025 17.019 204.9538 11.0312

800 0.5853 18.825 0.01 -0.001 -1.181 0.01 19.019 227.5713 4.8496

1000 0.7309 19.619 0.012 0.001 1.633 0.012 19.271 230.4021 2.9347

1500 0.8155 17.923 0.135 -0.001 -1.304 0.135 18.13 217.55 4.4537

2000 0.8417 21.47 0.07 0 -0.274 0.07 21.5 255.2579 13.7878

9000 1 25.645 0.019 0.011 12.839 0.019 22.328 264.3922 3.5741

Integrated 19.262 0.073 0.004 5.549 0.073 18.167 217.9696 1.4989

Sample: 93PH127B, University of Maine

mineral analyzed: white mica

 J = 0.00659, error not available 

Temp (°C) Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured Moles 39Ar Ca/K Cl/K Radio-genic 

yield (%) 

Age

(Ma)

+/-

(Ma)

675 0.028 15.85 0.034 0.0070 68.2 0.06942034

not

available

86.8 156.5 2.8

775 0.061 16.87 0.023 0.0028 146.1 0.046761749 95.1 181.3 1.8

845 0.080 19.40 0.082 0.0019 192.3 0.168038985 97.1 211.1 2.1

940 0.225 22.96 0.019 0.0014 543.2 0.038856077 98.1 249.7 2.4

1030 0.303 23.46 0.039 0.0013 732.8 0.08033419 98.3 255.3 2.6

1230 0.140 24.20 0.025 0.0011 338.0 0.050978793 98.5 263.4 2.5

1230 0.093 24.52 0.038 0.0016 223.5 0.077942323 98.0 265.2 2.5

fuse 0.071 24.86 0.062 0.0016 170.7 0.127000254 98.1 268.9 2.7

Total 1.000 2414.9 246.2 2.5

Sample: 96SK013A, UAF Sample number: UAF068-36

mineral analyzed: white mica

Weighted average of J from standards = 0.008468 +/- 0.000036

Laser 

Power

(mW)

Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured

% Atmospheric 40Ar Ca/K Cl/K 40*/39K Age

(Ma) 

+/-

(Ma) 

150 0.0002 81.21374 4.2257 0.03779 13.36443 7.77496 -0.01154 70.52921 844.81 477.15

300 0.0012 31.41048 -0.07985 0.07783 73.30371 -0.1465 0.00021 8.37734 123.64 187.23

600 0.0089 16.65318 0.06797 0.0105 18.63848 0.12472 0.00008 13.52653 195.64 20.02

900 0.0488 18.34407 -0.00526 0.00246 3.96875 -0.00965 0.0007 17.58842 250.48 3.71

1000 0.1174 18.15637 -0.00644 0.00215 3.5155 -0.01182 0.00016 17.49032 249.17 3.44

1250 0.2171 19.50602 -0.03185 -0.00009 -0.11973 -0.05845 0.00005 19.50024 275.72 3.31

1500 0.4233 19.03369 -0.01595 -0.00064 -0.9965 -0.02927 0.00018 19.19418 271.7 1.22

1750 0.4409 17.90656 -0.03581 -0.00142 -2.32743 -0.0657 0.00006 18.29352 259.83 12.5

2000 0.4468 16.15149 -0.43874 0.00098 2.00627 -0.80481 -0.0021 15.79481 226.47 34.24

2500 0.4553 15.73961 -0.32145 -0.00355 -6.5149 -0.5897 0.00012 16.73096 239.04 26.21

3000 0.6454 18.19726 -0.02224 -0.00004 -0.05114 -0.04081 0.0002 18.17759 258.29 1.22

3500 0.7989 18.34725 -0.01104 -0.00054 -0.86689 -0.02026 0.00019 18.47722 262.26 1.81

4500 0.8665 17.52531 -0.02737 0.00107 1.81802 -0.05022 0.00005 17.17821 245.01 5.27

9000 1 17.62192 -0.01705 -0.00039 -0.64739 -0.03128 0.00028 17.70692 252.05 1.99

Integrated 18.38226 -0.02165 0.00015 0.25274 -0.03972 0.00018 18.30692 260 1.36

Appendix. Argon analytical data for Permian metamorphic and igneous rocks in the Alexander terrane, southeastern Alaska.
 Appendix 43

Sample: 97PH045B, UAF Sample number: UAF068-36

mineral analyzed: white mica

Weighted average of J from standards = 0.009587 +/- 0.00003.817

Laser 

Power

(mW)

Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured

% 

Atmospheric 40Ar

Ca/K Cl/K 40*/39K Age

(Ma) 

+/-

(Ma) 

150 0.0022 26.1387 0.90209 0.06162 69.5 1.6562 0.00244 7.974 132.9 11.0

200 0.0041 18.8683 1.08873 0.03025 47.0 1.9991 0.00087 9.990 165.0 18.0

300 0.0189 19.8672 0.08483 0.01191 17.7 0.1557 0.00082 16.327 262.3 1.8

450 0.0515 18.1573 0.01773 0.00474 7.7 0.0325 0.00054 16.731 268.4 1.5

600 0.1184 16.4053 0.01387 0.00264 4.8 0.0255 0.00049 15.598 251.4 0.4

750 0.1789 17.3902 0.04232 0.00585 9.9 0.0777 0.00053 15.636 252.0 0.7

900 0.2480 17.5447 0.00910 0.00224 3.8 0.0167 0.00044 16.856 270.2 1.1

1050 0.3488 17.8893 0.02454 0.00494 8.2 0.0450 0.00047 16.403 263.5 1.2

1200 0.4445 16.8148 0.01938 0.00330 5.8 0.0356 0.00050 15.813 254.6 0.7

1500 0.5491 18.3263 0.01551 0.00577 9.3 0.0285 0.00054 16.595 266.3 1.5

2000 0.8501 16.9482 0.00728 0.00198 3.5 0.0134 0.00044 16.334 262.5 1.1

3500 0.9093 18.2418 0.00722 0.00335 5.4 0.0133 0.00026 17.225 275.7 0.9

6000 1.0000 17.0024 0.01100 0.00348 6.1 0.0202 0.00047 15.945 256.6 0.7

Integrated 17.3940 0.01956 0.00374 6.3 0.0359 0.00047 16.263 261.4 1.1

Sample: 97PH055B, UAF Sample number: UAF072-27

mineral analyzed: hornblende

Weighted average of J from standards = 0.009587 +/- 0.00003.817

Laser

(mW)

Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured

% 

Atmospheric 40Ar

Ca/K Cl/K 40*/39K Age

(Ma) 

+/-

(Ma) 

100 0.0005 267.2136 7.91187 0.38706 42.6 14.5924 0.27173 154.197 1637.3 119.0

150 0.0013 185.1073 7.37605 0.30192 47.9 13.5993 0.15645 96.880 1185.0 52.3

200 0.0022 110.9271 9.12270 0.17886 47.0 16.8389 0.11808 59.080 809.6 62.9

450 0.0049 196.5592 9.62625 0.20784 30.9 17.7742 0.17307 136.692 1510.8 20.7

800 0.0116 126.0535 13.88657 0.12138 27.6 25.7124 0.27268 92.032 1141.0 10.0

900 0.0407 30.1927 16.62288 0.01368 9.3 30.8344 0.08496 27.669 424.4 5.1

1050 0.1069 17.5321 14.39847 0.00658 4.9 26.6692 0.05078 16.799 269.4 1.8

1250 0.1855 19.6680 14.29552 0.00801 6.6 26.4767 0.06703 18.519 294.8 1.2

1500 0.2825 20.7989 14.42427 0.00788 6.0 26.7174 0.05753 19.708 312.2 1.3

2000 0.4517 17.6757 15.09632 0.00676 4.9 27.9746 0.03923 16.948 271.6 1.1

2500 0.6172 17.2021 16.55299 0.00710 5.0 30.7033 0.03744 16.496 264.9 1.2

3500 0.9231 17.3496 14.96834 0.00743 6.2 27.7351 0.04463 16.410 263.6 1.2

4000 0.9879 14.1315 12.82151 0.00557 4.8 23.7237 0.03302 13.533 220.1 2.3

4500 0.9945 13.8771 15.09251 0.00474 1.9 27.9675 0.03975 13.716 222.9 13.9

6000 0.9972 14.6922 14.74318 -0.00071 -9.0 27.3139 0.02433 16.134 259.5 37.6

8500 1.0000 14.1271 14.41929 0.00893 11.0 26.7081 0.03422 12.661 206.7 29.0

Integrated 19.5939 14.98073 0.00920 8.2 27.7583 0.04840 18.147 289.4 1.2

Appendix. Argon analytical data for Permian metamorphic and igneous rocks in the Alexander terrane, southeastern Alaska.—Continued
44 The Cannery Formation—Devonian to Early Permian Arc-Marginal Deposits Within the Alexander Terrane

Appendix. Argon analytical data for Permian metamorphic and igneous rocks in the Alexander terrane, southeastern Alaska.—Continued

Sample: 91SK168A, UAF Sample number: UAF061-08

mineral analyzed: white mica

Weighted average of J from standards = 0.007069 +/- 0.000014 

Laser 

Power

(mWatt)

Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured

% 

Atmospheric 40Ar

37Ca/39K Cl/K 40*/39K Age

(Ma)

+/-

(Ma)

100 0.0016 40.009 0.347 0.125 91.986 0.347

not

available

3.205 40.4 108.7

200 0.0082 22.446 0.102 0.024 31.097 0.102 15.447 187 25.2

300 0.0437 24.751 0.011 0.005 6.564 0.011 23.1 272.9 4.5

500 0.2116 23.797 -0.003 0.001 1.625 -0.003 23.382 276 1.6

700 0.2557 23.054 0 0.004 5.314 0 21.802 258.6 3.9

900 0.5398 24.271 -0.004 0.002 1.906 -0.004 23.78 280.3 1

1050 0.6924 22.69 -0.003 0 0.434 -0.003 22.563 267 1.3

1200 0.7491 21.228 -0.01 0 0.526 -0.01 21.088 250.7 2.8

1350 0.7689 21.567 0.017 0 -0.022 0.017 21.543 255.7 5.8

1500 0.7793 21.959 -0.048 0.007 9.416 -0.048 19.865 237.1 6.5

2000 0.8345 22.463 -0.004 0.001 1.195 -0.004 22.166 262.6 2.1

2500 0.8361 19.258 -0.016 0.01 14.927 -0.016 16.358 197.4 58.3

9000 1 24.428 -0.005 0.002 2.592 -0.005 23.767 280.2 1.6

Integrated 23.594 -0.003 0.002 2.448 -0.003 22.988 271.7 0.8

Sample number: 91SK168A, UAF sample number: UAF061-08 

mineral analyzed: white mica

Weighted average of J from standards = 0.007069 +/- 0.000014

Laser 

Power

(mWatt)

Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured

% 

Atmospheric 40Ar

37Ca/39K Cl/K 40*/39K Age

(Ma)

+/-

(Ma)

100 0.0005 184.311 1.518 0.739 118.424 1.52

not

available

-33.986 -495.6853 1455.609

200 0.0043 59.908 0.165 0.19 93.789 0.165 3.72 46.8252 177.4504

400 0.3251 28.583 -0.002 0.008 8.594 -0.002 26.1 305.4752 1.9414

600 0.8074 25.248 -0.001 0.004 4.15 -0.001 24.173 284.5988 1.7807

700 0.8181 26.099 0.041 0.028 31.185 0.041 17.941 215.4139 49.7254

800 0.8247 23.221 0.125 0.065 82.4 0.125 4.082 51.3235 92.6786

1000 0.8355 22.44 -0.101 0.023 31.011 -0.101 15.46 187.118 59.8095

1250 0.9017 24.748 -0.006 0.001 1.226 -0.006 24.416 287.2498 9.4787

1500 0.9493 25.174 -0.022 0.003 3.35 -0.022 24.302 286.0138 18.9603

2000 0.9696 25.457 -0.023 -0.013 -14.617 -0.023 29.145 337.9607 22.7239

2500 0.987 23.401 0.019 -0.001 -1.002 0.019 23.607 278.4289 23.3648

9000 1 26.012 -0.054 0.007 7.788 -0.054 23.959 282.2686 36.0968

Integrated 26.441 -0.002 0.006 7.231 -0.002 24.502 288.1822 2.1768
 Appendix 45

Appendix. Argon analytical data for Permian metamorphic and igneous rocks in the Alexander terrane, southeastern Alaska.—Continued

Sample number: 91SK047A, UAF Sample number: UAF087-25 

mineral analyzed: biotite

Weighted average of J from standards = 0.002516 +/- 0.000015

Laser 

Power

(mW)

Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured

% 

Atmospheric 40Ar

Ca/K Cl/K 40*/39K Age

(Ma) 

+/-

(Ma) 

150 0.0002 47.322 0.5070 0.0790 49.3 0.9305 0.0065 24.00 105.8 40.5

300 0.0007 42.110 1.2225 0.0351 24.4 2.2450 0.0155 31.83 139.0 18.7

500 0.0033 45.644 0.5543 0.0253 16.3 1.0173 0.0174 38.19 165.5 3.1

700 0.0140 69.201 0.0748 0.0196 8.4 0.1373 0.0191 63.38 266.9 1.0

900 0.0398 67.939 0.0242 0.0064 2.8 0.0443 0.0193 66.01 277.2 0.4

1100 0.0791 67.075 0.0148 0.0020 0.9 0.0271 0.0194 66.45 278.9 0.5

1300 0.1289 66.964 0.0122 0.0010 0.4 0.0225 0.0192 66.65 279.7 0.4

1500 0.1885 66.968 0.0132 0.0007 0.3 0.0242 0.0194 66.75 280.1 0.3

1800 0.2704 67.121 0.0177 0.0005 0.2 0.0325 0.0193 66.96 280.9 0.3

2100 0.3680 66.989 0.0275 0.0005 0.2 0.0504 0.0195 66.82 280.3 0.3

2500 0.4978 66.946 0.0422 0.0002 0.1 0.0775 0.0199 66.86 280.5 0.4

3000 0.6619 67.120 0.0667 0.0002 0.1 0.1224 0.0203 67.03 281.2 0.5

3500 0.8438 66.933 0.1156 0.0001 0.0 0.2121 0.0215 66.88 280.6 0.7

8700 1.0000 66.879 0.2938 0.0007 0.3 0.5392 0.0261 66.69 279.8 0.4

Integrated 66.965 0.0930 0.0009 0.4 0.1707 0.0210 66.68 279.8 1.6

Sample number: 91SK040A, UAF Sample number: UAF087-24

Weighted average of J from standards = 0.002516 +/- 0.000015

Laser 

Power

(mW)

Cumulative 39Ar

40Ar/39Ar

measured

37Ar/39Ar

measured

36Ar/39Ar

measured

% 

Atmospheric 40Ar

Ca/K Cl/K 40*/39K Age

(Ma) 

+/-

(Ma) 

150 0.0023 2364.644 10.5009 6.8028 85.0 19.4003 0.2190 357.63 1157.8 104.2

300 0.0087 449.331 20.0039 1.2901 84.5 37.1886 0.0838 70.49 294.5 51.2

500 0.0321 119.238 6.1109 0.2675 65.9 11.2575 0.0327 40.79 176.3 12.5

700 0.0819 47.307 2.6394 0.0629 38.9 4.8513 0.0224 28.94 126.8 5.2

900 0.1959 64.610 5.5510 0.0165 6.9 10.2223 0.1293 60.33 255.0 2.7

1100 0.3063 72.500 8.9449 0.0128 4.3 16.5087 0.1541 69.78 291.8 2.5

1300 0.4113 64.309 6.8914 0.0070 2.4 12.7018 0.1712 63.03 265.5 2.6

1500 0.5412 70.803 8.7845 0.0117 4.0 16.2111 0.1706 68.37 286.4 2.1

1800 0.6681 70.366 7.6961 0.0252 9.8 14.1924 0.1454 63.79 268.6 3.1

2100 0.7867 59.172 6.5268 0.0070 2.7 12.0269 0.1359 57.80 245.0 2.9

2500 0.8904 56.384 6.3521 0.0007 -0.5 11.7037 0.1280 56.85 241.2 3.3

3000 0.9780 48.427 4.1771 0.0032 1.3 7.6853 0.0848 47.91 205.3 4.6

8000 1.0000 63.014 5.9404 -0.0165 -8.4 10.9422 0.1097 68.56 287.1 13.1

Integrated 72.276 6.8197 0.0430 16.9 12.5689 0.1325 60.31 254.9 1.8

Produced in the Western Region, Menlo Park, California

Manuscript approved for publication, June 11, 2010

Text edited by George Havach

Layout and design by Jeanne S. DiLeo
Dumoulin and Galloway, eds.—Studies by the U.S. Geological Survey in Alaska, 2008–2009—Professional Paper 1776–B