U.S. Department of the Interior Bulletin 1969–B U.S. Geological Survey Plate 2 of 2 STRATIGRAPHIC CORRELATION CHART OF THE TERRANES OF THE ALASKA PENINSULA AND NEARBY TERRANES AND STRATIGRAPHIC UNITS OF SOUTHERN ALASKA [Wavy lines indicate areas of unconformity or disconformity. Shaded gray areas indicate missing section or nondepostion]

GEOLOGIC UNITS OF THE ALASKA PENINSULA TERRANE GEOLOGIC UNITS OF THE GEOLOGIC UNITS OF THE "HIDDEN" GEOLOGIC UNITS OF THE GEOLOGIC UNITS OF THE WRANGELLIA TERRANE GEOLOGIC UNITS OF THE SOUTHERN KAHILTNA TERRANE KAHILTNA ASSEMBLAGE CHUGACH TERRANE BLOCK (KNIK RIVER TERRANE) CHIGNIK SUBTERRANE ILLIAMNA SUBTERRANE

Plafker and others (1977); Connelly Pavlis (1983,1986); Roeske and other (1989); Detterman and others (1996); Detterman and Hartsock (1966); Detterman Detterman and others (1996); Detterman and Hartsock (1966); Detterman Jones and others (1977); Jones and MacKevett (1969); Plafker and others (1989); (1978); Moore (1974b) Burns (1985); Connelly and Moore (1978) and Reed (1980); this paper and Reed (1980); this paper MacKevett (1969; 1978) Wallace and others (1977) Jones and others (1977)

Hoodoo and Kaguyak Formations (Late Cretaceous, Maestrichtian and Campanian)—Siltstone, shale (Hoodoo >600 meters; Kaguyak >1,200 meters) Sedimentary rocks (Late Cretaceous and late Early Cretaceous; Maestrichtian Chignik Formation (Late Cretaceous; Maestrichtian and Campanian)— to late Albian)—Correlative with Matanuska Formation and consists of four Sandstone, siltstone, conglomerate, coal (~600 meters) formations Shumagin Formation, Kodiak Matanuska Formation (Late and Early Cretaceous; Maestrichtian to MacColl Ridge Formation (late Campanian or Maestrichtian)—Coarse Formation, and Valdez Group Albian)—Marine siltstone, shale, conglomerate (>4,500 meters) (Late Cretaceous; Maestrichtian sandstone, conglomerate (770 meters) and Campanian)—Graywacke Chititu Formation (late Campanian to Cenomanian)—Mudstone, shale, sandstone, siltstone, mudstone, subordinate porcellanite, sandstone, and limestone (1,700 meters) (>3,000 meters) Schulze Formation (late Cenomanian? to late Albian?)—Porcellanite, minor sandstone, and conglomerate (75 meters) Moonstone Creek Formation (late Cenomanian to late Albian)—Siltstone, sandstone, minor conglomerate (1,100 meters) FAULT CONTACT Kennecott Formation (Early Cretaceous, early Albian)—Sandstone, siltstone, minor conglomerate, shale, limy concretions (as much as 150 meters) Pedmar Formation (Early Cretaceous; Albian)—Sandstone, siltstone, shale

CRETACEOUS Marine sedimentary rocks (Early CRETACEOUS Uyak and McHugh Complexes (82 meters) Cretaceous to Late Jurassic; Melange, matrix (middle Cenomanian to Late Jurassic)— Cretaceous to Late Triassic, Complexly deformed marine, blocks as old as Pennsylvanian partly volcaniclastic flyschoid (?)) graywacke and pelitic rocks, minor Chert and volcanic sequence (Early Herendeen Formation and Nelchina Limestone (Early Cretaceous; Barremian chert, limestone, and conglomer- Cretaceous or Jurassic)—Chert and Hauterivian)—Calcarenite (270 meters) ate. Metamorphosed from zeolite Sedimentary rocks (Late Cretaceous, Hauterivian and Barremian)—Sandstone, and mafic volcanic rocks (KJcv) Staniukovich Formation (Early Cretaceous; Valanginian and Berriasian)— to amphibolite grade shale, impure bioclastic limestone (limestone equivalent to Nelchina Limestone, Siltstone, sandstone (246 meters) in part)

Naknek Formation (Late Jurassic; Tithonian to Oxfordian)—Unit subdivided into five members on the Alaska Peninsula Indecision Creek Sandstone Member (Tithonian and Kimmeridgian)— Sandstone, siltstone (870 meters) BASE NOT EXPOSED INTRUSIVE CONTACT Katolinat Conglomerate Member (Tithonian)—Conglomerate, sandstone Root Glacier Formation (Late Jurassic; Kimmeridgian and late Oxfordian) — (450 meters) Marine volcanogenic mudstone, siltstone, sandstone, conglomerate Snug Harbor Siltstone Member (Kimmeridgian and Oxfordian)—Siltstone, (~1,000 meters) sandstone (<638 meters) Northeast Creek Sandstone Member (Oxfordian)—Sandstone, siltstone Kosetna River sequence (Early Cretaceous? to Late Jurassic?; Valanginian to (624 meters) Kimmeridgian)—Complexly deformed marine volcaniclastic turbidite Chisik Conglomerate Member (Oxfordian)—Conglomerate, sandstone sandstone and shale, conglomerate (614 meters)

Shelikof Formation (Middle Jurassic; Callovian)—Volcanoclastic graywacke sandstone, conglomerate, shale (>1,400 meters). Laterally equivalent to Paveloff Siltstone Member, Chinitna Formation Granitic rocks (Late? and Middle Jurassic)—Hornblende-biotite granodiorite of the Alaska-Aleutian Range batholith, although quartz diorite and granite are Chinitna Formation (Middle Jurassic; Callovian)—Chinitna in part comformable Kotsina Conglomerate (Late locally present. Potassium-argon age determinations yield ages in the range with the overlying Naknek Formation. Unit subdivided into two members or Middle Jurassic)- 153±4.6 to 174.7±8.8 Ma Conglomerate, sandstone, Paveloff Siltstone Member (Middle Jurassic; Callovian)—Marine arenaceous shale (>500 meters). siltstone, basal sandstone, limestone beds and concretions, minor sandstone Overlies McCarthy interbeds (400 meters) Formation Tonnie Siltstone Member (Middle Jurassic; early Callovian)—Marine arena- ceous siltstone, minor sandstone interbeds, limestone concretions, basal BASE NOT EXPOSED conglomerate locally (400 meters) Tuxedni Group (Middle Jurassic)—Consists of six, possibly seven, formations in this area Bowser Formation (Middle Jurassic; Callovian and late Bathonian?)—Hetero- geneous assemblage of graywacke sandstone, conglomerate, shale, and siltstone (~500 meters) Nizina Mountain Formation (Late and Middle Jurassic; Callovian and INTRUSIVE CONTACT Bathonian)—Marine graywacke sandstone (410 meters) Twist Creek Siltstone (Middle Jurassic; early late Bajocian)—Graywacke sandstone and conglomerate, minor siltstone and limestone concretions JURASSIC JURASSIC (180 meters)

Cynthia Falls Sandstone (Middle Jurassic; middle Bajocian?)—Graywacke siltstone and conglomerate, minor siltstone, and limestone concretions

Fitz Creek Siltstone (Middle Jurassic; early middle Bajocian)—Arenaceous siltstone, limestone concretions, minor sandstone and locally conglomerate (330 meters) Gaikema Sandstone (Middle Jurassic; early middle Bajocian)—Graywacke and feldspathic sandstone, minor siltstone, shale, and conglomerate. Conglomer- ate is dominantly volcanic clasts, however a few granitic clasts occur (260 meters) Red Glacier Formation (Middle Jurassic; middle and early Bojacian)— BRUIN BAY FAULT BRUIN BAY

Assemblage of siltstone, arkosic sandstone, shale, minor subgraywacke, NO KNOWN FAULT NO KNOWN FAULT conglomerate, and limestone (>1,350 meters) FAULT AND INTRUSIVE (?) CONTACT Kialagvik Formation (Middle and Early Jurassic; Callovian to late Toarcian)— BOUNDARY DEPOSITIONAL

CONTACT RELATION UNKNOWN RELATION CONTACT Sandstone, shale, conglomerate (>620 meters). As described here, may also include the lower part of the Tuxedni Group BORDER RANGES FAULT SYSTEM (IN PART) BORDER RANGES FAULT

Talkeetna Formation (Early Jurassic; Hettangian and early Talkeetna Formation (Early Jurassic; Hettangian and early Sinemurian)—In Sinemurian)—In map area, consists of tuffaceous sandstone and tuff that map area, consists of tuffaceous sandstone and tuff that lithically closely lithically closely resemble the Horn Mountain Tuff Member (405 meters). Lubby Creek Formation (Early Jurassic; Toarcian and late Pliensbachian)— resemble the Horn Mountain Tuff Member (405 meters). Elsewhere consists of Marine spiculite and coquina (90 meters) Diorite (Early Jurassic and Triassic)— three members Elsewhere consists of two members Includes Afognak pluton (age range Horn Mountain Tuff Member (Early Jurassic; Toarcian and upper Pleinsba- Horn Mountain Tuff Member (Early Jurassic; Toarcian and upper approximately 190–204 Ma) Pleinsbachian in Talkeetna Mountains; Hettangian and early Sinemu- chian in Talkeetna Mountains; Hettangian and early Sinemurian in map TOP OF DEFINED TERRANE Raspberry and Seldovia Schists of Roeske area)—Tuff and tuffaceous sandstone, volcanic flows (550 meters) rian in map area)—Tuff and tuffaceous sandstone, volcanic flows (1986) and schist of Iceberg Lake (550 meters) Portage Creek Agglomerate Member (Early Jurassic)—Agglomerate, volcanic (metamorphic age, Early Jurassic and breccia and flows, and tuffaceous sandstone (~700 meters) Portage Creek Agglomerate Member (Early Jurassic)—Agglomerate, Triassic)—Mafic schist, hornblende- volcanic breccia and flows, and tuffaceous sandstone (~700 meters) biotite, schist, glaucophane schist, Marsh Creek Breccia Member (Early Jurassic)—Volcanic breccia, flows greenstone, and tuff (1,000 meters) Marsh Creek Breccia Member (Early Jurassic)—Volcanic breccia, flows McCarthy Formation (Early Jurassic and Late Triassic; Pliensbachian to greenschist and amphibolite, quartz-mica greenstone, and tuff (1,000 meters) Norian)—Marine chert, spiculate, shale, limestone, and impure limestone schist, marble, migmatite, gneiss (900 meters) Border Ranges ultramafic and mafic complex Nizina Limestone (Late Triassic; middle Norian to late Karnian)—Limestone and Kamishak Formation (Late Triassic; Norian)—In map area, consists of Kamishak Formation (Late Triassic; Norian)—In map area, consists of of Burns (1985) (Early Jurassic? and chert (500 meters) Triassic?)—Dunite, gabbro, peridotite Bruin Limestone Member—Limestone, calc-siltsone and mudstone, calc- Bruin Limestone Member—Limestone, calc-siltstone and mudstone, calc- Chitistone Limestone (Late Triassic; Karnian)—Limestone (600 meters) conglomerate (~800 meters) conglomerate (~800 meters) Elsewhere, consists of three members Elsewhere, consists of two members Ursus Member (Late Triassic)—Thin-bedded limestone, chert, tuff Ursus Member (Late Triassic)—Thin-bedded limestone, chert, tuff (~150 meters). May not be correlative with upper member of McCarthy Formation (~150 meters). May not be correlative with upper member of McCarthy Middle member (Late Triassic; middle and late Norian)—Deformed Formation thin-bedded limestone, chert, tuff (~530 meters). Correlative with lower member Middle member (Late Triassic; middle and late Norian)—Deformed Nikolai Greenstone (Late Triassic; early Karnian to late Ladinian)—Basalt, Chilikadrotna Greenstone of Wallace and others (1989) (Late Triassic; of McCarthy Formation thin-bedded limestone, chert, tuff (~530 meters). Correlative with lower mainly subaerial flows, lower part contains pillow basalt and argillite, volcanic FAULT CONTACT Norian)—Greenstone (basalt), locally pillowed; rare interpillow limestone and Bruin Limestone Member (Late Triassic; Norian)—Medium-bedded to massive member of McCarthy Formation conglomerate (3,000 meters) chert, andesitic flows, tuff. Associated limestone, chert, cherty shale, and tuff limestone, calc-siltstone, chert (>600 meters) Bruin Limestone Member (Late Triassic; Norian)—Medium-bedded to massive Sedimentary rocks (Late Triassic; middle Ladinian)—Chert, siltstone, shale Volcanic rocks (Late Triassic)—Columnar-jointed basalt flows, volcanic breccia, limestone, calc-siltstone, chert (>600 meters) (100 meters) TRIASSIC TRIASSIC and agglomerate. Interbedded with Kamishak Formation at Puale Bay BASE NOT EXPOSED BASE OF DEFINED TERRANE Shuyak Formation (Triassic)—Metabasite, pillow lavas, volcanoclastic sandstone, Cottonwood Bay Greenstone (Late Triassic; Norian?)—Greenstone conglomerate, argillite, tuff (>400 meters). Some rocks locally included herein in the Kakhonak(?) Complex (JPk) are greenstone but close association with the Kamishak Formation suggests a Late Triassic (Norian?) age

PROBABLE FAULT CONTACT

Kakhonak Complex (early Late Jurassic? to Permian?)— Heterogeneous assemblage of metamorphic rocks, includes meta-limestone, quartzite, greenstone and other metavolca- Limestone (late middle Permian; early Guadalupian)—Limestone, chert nics, and schist. Lithology indicates that precursors were Meta-chert, meta-argillite (middle Permian?) (40 meters) similar to the Permian limestone, Cottonwood Bay Green- Volcanic rocks (Permian?)—Massive, dark-green to black volcanic breccia, stone, and Kamishak and Talkeetna Formations in the agglomerate, and andesitic flows adjacent Chignik subterrane BASE NOT EXPOSED

BASE NOT EXPOSED PERMIAN PERMIAN Skolai Group (>2,500 meters)—Consists of three formations Hasen Creek Formation (Early Permian)—Nonvolcanic marine argillite, shale, sandstone, chert, limestone, conglomerate (600 meters) Limestone (early Guadalupian and Wolfcampian)—Fossiliferous limestone (0–250 meters) Station Creek Formation (earliest Permian and Pennsylvanian)—Submarine and andesitic volcaniclastic rocks (>1,200 meters), andesitic and basaltic volcanic rocks

BASE NOT EXPOSED PENNSYLVANIAN PENNSYLVANIAN

Stratigraphic Correlation Chart of Alaska Peninsula and Nearby Terranes Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government By For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 1–888–ASK–USGS Frederic H. Wilson1, Robert L. Detterman2, and Gregory D. DuBois1 Digital files available at http://dx.doi.org/10.3133/b1969B or http://pubs.usgs.gov/bul/1969b/ 1 Suggested citation: Wilson, F.H., Detterman, R.L., and DuBois, G.D., 2015, Geologic framework of the U.S. Geological Survey; Alaska Peninsula, southwest Alaska, and the Alaska Peninsula terrane: U.S. Geological Survey 2015 2 Deceased http://dx.doi.org/10.3133/b1969B Bulletin 1969–B, scale 1:500,000, 2 plates, 34 p., http://dx.doi.org/10.3133/b1969B