DEPARTMENT OF THE INTERIOR PREPARED IN COOPERATION WITH MISCELLANEOUS FIELD STUDIES GEOLOGICAL SURVEY THE STATE OF DEPARTMENT OF NATURAL RESOURCES 140° MAP MF- 673 SHEET 2 OF 2 EXPLANATION 138° CORRELATION OF MAP UNITS

METAMORPHIC ROCKS 136° STRATIFIED SEDIMENTARY AND VOLCANIC ROCKS VOLCANIC ROCKS PLUTONIC AND HYPABYSSAL ROCKS 134° Mainly marine. In part metamorphosed FELSIC ROCKS MAFIC ROCKS ULTRAMAFIC ROCKS 8

Holocene deposits

Quaternary Quaternary volcanic rocks deposits

. AiR\t, : "i°H· ;-·Ft •·•:~•::-: • • ••••• L ; ()Jaternary and Tertiary volcanic rocks C") ·<[!'·\:,., .. 0 .r z :,.·:·:•:··:.--=_.:_:· 2 "' g Upper Tertiary rocks @ o~ I '\>· w 0 I ', (j ICT. LA Middle Tertiary rocks T Tv r,,,, Tertiary rocks Tertiary voloonic rocks Tertiary granitic rocks Tertiary mafic rocks 7,, 8

Eocene granitic rocks IT

Lower Tertiary rocks

I "'' I ~_K_,__ I Tertiary and Cretaceous granitic rocks }(;;;, Gretoceous volcanic rocks Cretaceous granitic rocks Cretaceous mafic rocks Cretaceous ultramafic rocks PACI Fl C Lower Cretaceous rocks \~,.,,., j KJ j KJv I KJ, Upper Mesozoic rocks Cretoceous and Jurassic volcanic rocks ~-J_,_ ~j Cretaceous and Jurassic granitic rocks uMzi, Cretaceous and Upper Jurassic('?) rocks KJ, Lower Cretaceous and Upper Jurassic rocks Jurassic granitic rocks Mesozoic mofic rocks Mesozoic ultromafic rocks I J "Ji I Ir- J-,,- J"1im EL L ' '- 7i Jurassic and(or) Triassic rocks Jurassic or Triassic gronitic,rocks Jurassic or Triassic Triassic rocks Triassic volcanic rocks metamorphic rocks ·:;--, _._

I RP M,/i 1 '"'a, 1 M,&m I 8 p Triassic and Permian rocks Mesozoic and Paleozoic rocks Mesozoic and Paleozoic Mesozoic .or Paleozoic granitic rocks Mesozoic or Paleozoic Permian rocks volcanic rocks metamorphic rocks '1,;;;, 13 PIP y IP Permian and Pennsylvanim rocks ~ Pennsylvanian rocks Upper Paleozoic rocks 0 0~= ====~50 100 MILES M (j 0 50 100 KILOMETRES Mississippian rocks 0 tlw __J D Paleozoic rocks Dv Paleozoic volcanic rocks Paleozoic granitic rocks Paleozoic metamorphic rocks Index Map Showing Principal Sources of Geologic Data "'a. Devonian rocks Devonian volcanic rocks DS Ill s Devonian and Silurian rocks s, I I 11,, Silurian rocks Lower Poleozoic rocks Silurian or older Lower Paleozoic SD granitic rocks granitic rocks SOurn Silurian and Ordovician rocks o, Silurian and Ordovician ultramafic rocks Ordovician granitic rocks 54° -0 ;;o

;:::~ Pre-Middle Ordovician rocks ;;o "' SOURCES OF DATA zJ> q [ Unless otherwise indicated, all pu blications are those of the U. S. Geological Survey]

Granitic rocks of unknown age Ultromafic rocks of unknown age 1. Mbc. Geol Inv. Map I-484, 1:500,000, 1967. Modified by the author . 2. Prof. Paper 832, pl. l, 1:63,360, 1974. DESCRIPTION OF MAP UNITS 3. Misc. Geol. Inv. Map 1-303, 1:250,000, 1959. 4. Prof. Paper 792, pl. l, 1:250,000, 1975. [in press]

STHATIFIED SEDIMENTARY AND VOLCANIC ROCKS. 5. Bull. 118lwR, pl. 1, 1 :250,000, 1965. CM:] MISSISSIPPIAN ROCKS .-- Lime stone and dolomite with interbedded chert of Early and Late Mississippian age. Con­ FELSIC ROCKS MAP SYMBOLS MAINLY MARINE. IN PART METAMORPHOSED sists of t he lyoukeen Formation on Chichagof Island and the Peratrovich Formation on Prince of Wales Island [!£] TERTIARY GRANITIC ROCKS.--Quartz diorite and granodiorite with minor quartz monzonite and mafic intrusive 6. Bul l. 800, pl. 1, l:500,000, 1929. u!iJ HOLOCENE DEPOSITS.--Alluvial , gl acial, lacustrine, and beach deposits [TI PALEOZOIC ROCKS.--Argillitc, conglomerate, graywacke , chert, limestone, marble, and minor hornfels in the 7. Bul l. 1247-C, pl. l, l:63,360, 1967. rocks in the area; quartz diorite and subordfoate granodiorite north of Lynn Canal; grano­ . Contact,------approximotely located [:QJ QUATERNARY OEPOSITS.--Alluvial, colluvial, glacial, lake, and beach deposits Canada Geol. Surve,y open-file rept. 214, 1 :1,000 000 , 7974. Chi lkat Range west of the Lynn canal; hornfels, schist, and marble on Chichagof Island; and marble and meta­ diorite and tonal ite on Chich,1gof Island; and granodiorite and granite east of Juneau Dotted where conceoled or infer red $. 1 ~ UPPER TERTIARY ROCKS.--Siltstone, sandstone, and conglomeratic sandy mudstone (marine till ite) of Miocene and volcanic rocks on western Etol fo Island EOCENE GRANITIC ROCKS.--Granodiorite, tonalite, trondhjemite, and granite on Chichagof, Kruzof, and Baranof 9. Ovenshine, A. T., unpublished compilation. (lliJ Fault, opproximately located Pliocene age. Consists of Yakataga Fonnation in Gulf of Alaska area IT] DEVONIAN ROCKS.--Unmetamorphosed argillite, chert, and limestone of the Hood Bay Formation (Devonian?) on Islands, and Hyder Quartz Monzonite and unnamed quartz monzonite and granodiorite near Hyder Dotted where concealed or inferred 9a. Berg, H. C., unpublished data. j mT I MIDDLE TERTIARY ROCKS.--Calcareous siltstone and sandstone of Oligocene to early Miocene age. Consists of western Admiralty Island and possi ble equivalent rocks ii, the Chilkat Range west of Lynn Canal; schist TERTIARY AND CRETACEOUS GRANITIC ROCKS.--Granodiorite, quartz monzonite, and granite in the Fairweather 10. Bull. 1284, pl. 1, 1:125,000, 197 0. @iJ Vo lcanic vent or cone To psy Formation in the Gulf of Alaska area phyllite, marble, and amphibolite of the Retreat Group and Gambier Bay Formation (Middle? Devonian) on Range; quartz d1orite and subordinate granodiorite north of Lynn Canal; quartz monzonite west of Juneau; 11. Eberlein, G.D., and Churkin, Michael, Jr., unpublished compilation. [I] TERTIARY ROCKS.--Nonmarine sandstone, coal, conglomerate, and shale of Pa leocene through Miocene age. Con­ Admiralty and Kupreanof Islands and possible equivalent rocks to the south; basaltic submar-ine flows, luff, and granodiorite and quartz diorite southwest of Hyder lla. Bull. 1154, pl. 7, 1:24,000, 1963. sists of the kootznahoo Formation on Admiralty, Kuiu, Kupreanof, and Zaremba Islands breccia, and conglomerate (St. Joseph Island Volcanics of Devonian(?) age), basaltic rocks with foterlayered ~ CRETACEOUS GRANITIC ROCKS.-·Diorite, tonalite, and granodiorite near Glacier Bay; quartz diorite and sub­ ll b. Bull. 1058-H, pl. 33, 1:63,360, 1967. LJLl LOWER TERTIARY ROCKS.--Nonmarine sandstone and conglomerate with thin coal seams of Eocene and early Oligocene limestone (Coronados Volcanics of Middle Devonian age), limestone breccia and shale (Wadleigh Limestone of ordinate granodiorite near Haines; quartz monzonite, granodiorite, tonalite, and diorite on Chichagof 12. Clark, A. L., unpublished compilation. age south of Kassan Bay on Prince of Wales Island and arkose, siltstone, and coal of Paleocene and Eocene Middle and Late Devoni an age), and graywacke and conglomerate (lower part of the Port Refugio Formation of Island, quartz diorite and granodiorite with small bodies of gabbro on Admiralty Island; granodiorite, 13. Canada Geo1. Survey open-file rept. 166, 1:1,000,000, 1973. age in the Kulthieth Formation no r th of Yakataga Bay Mi ddl e and Late Devonian and Mississippian age) on Prince of Wales Island quartz monzonite, and diorite on Kuiu Island; and rocks ranging in composition from granodiorite to diorite 14. Smith, J. G,, unpublished compilation. [JTI LOWER CRETACEOUS ROCKS.--Graywacke, argillite, and minor andesite on Etolin Island ~ DEVONIAN AND SILURIAN ROCKS.--Siltstone, mudstone, limestone, conglomerate, sandstone, graywacke and minor in the Coast Range Mountains and on Prince of ~/ales Island 15. Berg, Ii. C., unpublished compilation. UPPER MESOZOI C ROCKS: INCLUDES: red beds and volcanic rocks. Inc l udes the Rendu Formation and Willoughby Limestone in the Glacier Bay (ID CRETACEOUS AND JURASSIC GRANITIC ROCKS.--Quartz diorite on Dall and Forrester Islands 16. Bull. 1373, pl. 1, 1:63,360, 1973. \uMi. 1 I CRETACEOUS AND UPPER JURASSIC(?) ROCKS.--Graywacke, argillite, and slate with minor conglomerate and, local ly, area; the Kennel Creek Limestone on Chichagof Island; the Karheen Formation on Prince of Wales Island; []i] JURASSIC GRANITIC ROCKS.--Granodiorite in the Alaska Range and in the Chilkat Range; quartz monzonite, 17. Misc. Geol. Inv. Map I-684, 7:63,360, 7972. n1elange ranging in age from Late Jurassic(?) to Late Cretaceous (Campanian}. Consists mai nly of the Yakutat and related rocks on Dall Island alaskite, monzonite, diorite, and tonalite on Chichagof Island and Baranof Island; and granite on southern Group in the Gulf of Alaska area IT] SILURIAN ROCKS.--Includes unnamed graywacke, shale, siltstone, and calcarenite north of the Glacier Bay and Prince of Wales Island (:JiiJ LOWER CRETACEOUS AN D UPPER JURASSIC ROCKS.--Graywacke, argil lite, slate, and minor conglomerate and limestone in the Chi1 kat. Rang e ; graywacke, slate, 1 imestone, and conglomerate of the Point Augusta Formation on G!:!i} JURASSIC OR TRIASSIC GRANITIC ROCKS. --Texas Creek Granodiorite north of Kyder ranging in age from Late Jurassic (Oxfordian and Kimmeridgian) to Early Cretaceous (Albian). Includes the l70'E 181> 0 Chichagof Island, calcareous sandstone and argillite of the Bay of Pillars Format.ion on Admiralty, Kuiu, IMi-Ttgl MESO ZOIC OR PALEOZOIC GRANITIC ROCKS. --Metadiorite of late Paleozoic or early Mesozoic age on Cape Fox and 170°W I 3o" Sitka Graywacke on Chichagof and Baranof Islands, the Seymour Canal Formation on Admiralty and northern and Prince of Wales Islands (also includes the overlying Kuiu Limestone and unnamed arkose, volcanic gray­ at the southern tip of Gravina Island Kupreanof Islands, slaty detrital rocks of late Jurassic age on Gravina and Annette Islands, and related wacke, and argillite on Kuiu Island); and massive limestone of the Heceta Limestone on Prince of Wales, unnamed rocks UaJ PALEOZO IC GRANITIC ROCKS.--Granodiorite and related intrusive rocks on Prince of \~ales Island Kosciusko, and Coronation Islands [ill JURASSIC AND(OR) TRIASSIC ROCKS. --Greenstone, schist, phyllite, graywacke, amphibolite, gneiss, and limestone ~ SILURIAN OR OLDER GRANITIC ROCKS.--Syenite, monzonite, granodiorite, and trondhjemite on Chichagof Island; [ii] LOWER PALEOZOIC ROCKS.--lncludes Puppets Formation and unnamed greenstonE, phyllite, schist, limestone, and of Triassic and(or) Jurassic age. Consists of Khaz Formation on Chichagof, Kruzof, and Claranof Islands leucotrondhjemite with subordinate trondhjemite, quartz diorite, diorite, granite, qiJartz monzonite, and dolomite of Devonian and Silurian or older age on Gravina and Annette Islands. Metamorphosed in places to [I] TRIASSIC ROCKS.--Chert , limestone, sandstone, and greenstone of Triassic age and the Whitestripe Marble and granodiorite on central Annette Island; quartz diorite on western Annette Island; and trondhjemitic-rocks greenschist faci es an d to amphibol ite facies on Gravina Island ALASKA Pinnacle Peak Phy11ite of Triassic(?) age on Chichagof and Baranof Islands; volcanic r ocks, limestone, shale, --- [§Q] SILURIAN AND ORDOVICIAN ROCKS .--Graywacke, conglomerate, cherty shale and siltstone, basaltic tuff and lava, ,' chert, and conglomerate of the Kyd Group of Late Triassic age on Admiralty Island and Keku Straits area; ~ LOWER PALEOZOIC GRANITIC ROCKS.--Quartz diorite and diorite on Annette Island . ) and local limestone. Includes the Descon Formation of Early Ordovician through Early Silurian age on ,' altered basaltic flows, conglomerate, grit, sandstone, and limestone of the Ne he nta and Chapin Peak Formations ~ ORDOVICIAN GRANITIC ROCKS. - -Quartz monzonite and quartz diorite on Prince of Wales Island Prince of Wales Island ,' % of Late Triassic age on Gravina Island; and unnamed 1 imestone, siltstone, and sandstone on Etol in, Annette, ~ GRANITIC ROCKS OF UNKNOWN AGE.--On Prince of Wales and Rev111agigedo Islands and nearby areas M F-611 MF-612 [ill PRE -MIDDLE ORDOVICIAN ROCKS.--Heterogeneous, mainly volcanogenic greenschist and semischist, with locally and Revillagigedo Islands MAFIC ROCKS interstratified marble. Includes the Wales Group, which rna_y be at least as old as Cambrian, and probably j T,..,;I TERTIARY MAFIC ROCKS.--Gabbro and hornblende diorite on Chichagof Island: gabbro on Yakobi Island; gabbro (ill TRIASSIC AND PERMIAN ROCKS.--Schist, schistose graywacke, slate, conglomerate and phyllite with minor volcanic Precambrian and microgabbro along Keku Straits; and gabbro southwest of Hyder flow breccia and anciesite flows at the northern tip of Admiralty Island . Includes the Barlow Cove Formation VOLCANIC ROCKS ~ CRETACEOUS MAFIC ROCKS.--Gabbro on Chichagof Island; hornblendite, gabbro. and subordinate diorite on of Pennian and Triassic(?) age. On the southern part of Admiralty Island, includes an unnamed series of ~ QUATERNARY VOLCANIC ROCKS.--Andesitic and basaltic flows of the Edgecumbe Volcanics on Kruzof I sland, on Admiralty Island , and gabbro on Kuiu Island an desitic flo1vs and tuffs, minor chert, and micaceous schist western Revillagigedo Island and nearby areas, and on the Unuk River northeast of the island I Pb-mil MESOZOIC MAFJC ROCKS.--Gabbro in Gulf of Alaska area [filJ MESOZOIC AND PALEOZOIC ROCKS.- -Slate, phyllite, quartzite, schist and phyllite with interlayered beds of I QTv I QUATERNARY AND TERTIARY VOLCANIC ROCKS.--Tlevak Basalt (Tertiary or Quaternary) on Prince of Wales Island ULTRAMAFIC ROCKS THIS MAP and unnamed basalt flows on Suemez and Dall Islands marble , layered gneiss with interlayered beds of marble, and minor amphibolite. Includes rocks that may I 1

,; D. s. GOVERNMP.Nr PRINl'rnG OFF ICE: 1975-0-690-036/27