NáðMAP_UNITC UNIT_NAMECnAGECHDESCRIPTIOCþFOSSILCþRADIOMETRICþSOURCECCLASSNQUADRANGLECROCK_CLASSCNSACLASSNLABELCNSAMODCQCLASSN nm Not mapped Areas not mapped on Saint Matthew and Hall Islands ST002999 Saint Matthew 98 98 Q Surficial deposits Quaternary Undifferentiated beach, bar, alluvial, and colluvial deposits. Mostly gravel and sand ST0021 Saint Matthew Unconsolidated100 1000 Qu Surficial deposits Quaternary Undifferentiated fluvial and marine gravel, sand, silt, and mud; organic materials; eolian sand and silt; and colluvium. BI0021 Baird Inlet Unconsolidated100 1000 Qu Surficial deposits Quaternary Undifferentiated fluvial and marine gravel, sand, silt, and mud; organic materials; eolian sand and silt; and colluvium. NI0021 Nunivak Island Unconsolidated100 1000 Qu Surficial deposits Quaternary Undifferentiated fluvial and marine gravel, sand, silt, and mud; organic materials; eolian sand and silt; and colluvium. KB002100 Kuskokwim Bay Unconsolidated100 1000 Qa Alluvium Holocene and Pleistocene Unconsolidated alluvial, colluvial, glacial outwash, lacustrine, and eolian conglomerate, sand, silt, and mudrock BH002105 Bethel Unconsolidated100 1000 Qu Unconsolidated deposits Holocene Unconsolidated deposits NI003110 Nunivak Island Unconsolidated100 1000 Qu Unconsolidated deposits Holocene Unconsolidated deposits CM003110 Cape Mendenhall Unconsolidated100 1000 Qu Surficial deposits Quaternary Undifferentiated fluvial and marine gravel, sand, silt, and mud; organic materials; eolian sand and silt; and colluvium. KB003300 Kuskokwim Bay Unconsolidated100 1000 Surficial deposits, undivided Quaternary? Areas on map not assigned to bedrock geologic units, assumed to be surficial deposits. Not described. GO005501 Goodnews Bay Unconsolidated100 1000 Surficial deposits, undivided Quaternary? Areas on map not assigned to bedrock geologic units, assumed to be surficial deposits. Not described. HG003501 Hagemeister IslandUnconsolidated100 1000 Surficial deposits, undivided Quaternary? Areas on map not assigned to bedrock geologic units, assumed to be surficial deposits. Not described. NG006501 Nushagak Bay Unconsolidated100 1000 Qc Colluvium Quaternary Chiefly frost-rived rubble, loccally includes stream alluvium, terrace gravels, glacial deposits, and windblown silt HG005607 Hagemeister IslandUnconsolidated100 1000 Qs Surficial deposits, undivided Quaternary NG007701 Nushagak Bay Unconsolidated100 1000 Qc Colluvium Quaternary Chiefly frost-rived rubble, locally includes stream alluvium, terrace gravels, glacial deposits, and windblown silt GO008707 Goodnews Bay Unconsolidated100 1000 Qc Colluvium Quaternary Chiefly frost-rived rubble, locally includes stream alluvium, terrace gravels, glacial deposits, and windblown silt GO006807 Goodnews Bay Unconsolidated100 1000 Qc Colluvium Quaternary Chiefly frost-rived rubble, but locally includes small amount of bog deposit, flood-plain alluvium, terrace deposit, glacial gravel, and wind-blown silt. BH0043107 Bethel Unconsolidated100 1000 Tidal flat deposits Quaternary, Holocene Undifferentiated fluvial and marine gravel, sand, silt, and mud; organic materials BI0012 Baird Inlet Unconsolidated103 1030 Tidal flat deposits Quaternary, Holocene Undifferentiated fluvial and marine gravel, sand, silt, and mud; organic materials KB001103 Kuskokwim Bay Unconsolidated103 1030 Qtf Tidal flats Quaternary, Holocene NG001103 Nushagak Bay Unconsolidated103 1030 Tidal flat deposits Quaternary, Holocene Undifferentiated fluvial and marine gravel, sand, silt, and mud; organic materials HG001603 Hagemeister IslandUnconsolidated103 1030 Tidal flat deposits Quaternary, Holocene Undifferentiated fluvial and marine gravel, sand, silt, and mud; organic materials GO001703 Goodnews Bay Unconsolidated103 1030 Qa Alluvial deposits Holocene Flood-plain alluvium (sand, gravel, and boulders), beach (sand and small pebbles) and estuarine deposits (clay rich silt), and dunes (fine-grained sand). GO002105 Goodnews Bay Unconsolidated105 1050 Qa Alluvial deposits Holocene Flood-plain alluvium (sand, gravel, and boulders), beach (sand and small pebbles) and estuarine deposits (clay rich silt), and dunes (fine-grained sand). HG002105 Hagemeister IslandUnconsolidated105 1050 Qal Alluvial deposits Holocene Flood-plain alluvium (sand, gravel, and boulders), beach (sand and small pebbles) and estuarine deposits (clay rich silt), and dunes (fine-grained sand). NG002105 Nushagak Bay Unconsolidated105 1050 Qf Flood plain alluvium Quaternary Alluvium, includes some beach deposits HG005605 Hagemeister IslandUnconsolidated105 1050 Qf Flood plain alluvium Quaternary Alluvium, includes some beach deposits GO008705 Goodnews Bay Unconsolidated105 1050 Qa Alluvial deposits Holocene Flood-plain alluvium (sand, gravel, and boulders), beach (sand and small pebbles) and estuarine deposits (clay rich silt), and dunes (fine-grained sand). NG007705 Nushagak Bay Unconsolidated105 1050 Qf Flood-plain alluvium Quaternary Mud, silt, sand, gravel, boulders, and intermixed wood, peat, and other vegetal material. BH0043105 Bethel Unconsolidated105 1050 Qal Alluvial deposits Quaternary Alluvial ssand, gravel, and silt along major streams and rivers. Deposits are locally transitional to undivided surficial deposits, estuarine and tidal flats deposits. Locally older alluvium may constitute the material of marine terraces KB0033105 Kuskokwim Bay Unconsolidated105 1050 Qal Alluvial deposits Quaternary Alluvial ssand, gravel, and silt along major streams and rivers. Deposits are locally transitional to undivided surficial deposits, estuarine and tidal flats deposits. Locally older alluvium may constitute the material of marine terraces BI0033105 Baird Inlet Unconsolidated105 1050 Qrs Reworked silt deposits Quaternary Silt, sandy silt, and bog deposits GO008710 Goodnews Bay Unconsolidated113 1130 Qrs Reworked silt Quaternary Chiefly reworked silt, sandy silt, and bog deposits underlying a plain transitional with or slightly above areas of flood-plain alluvium of Recent age and separated from higher plains and residual 'islands' of older silt deposits by an erosional scrap 10 BH0043110 Bethel Unconsolidated113 1130 Qrs Reworked silt Quaternary Derived by extension from adjacent Goodnews Bay quadrangle map. Chiefly reworked silt, sandy silt, and bog deposits underlying a plain transitional with or slightly above areas of flood-plain alluvium of Recent age and separated from higher plains and r KB0033113 Kuskokwim Bay Unconsolidated113 Q 1130 Qrs Reworked silt Quaternary Chiefly reworked silt, sandy silt, and bog deposits underlying a plain transitional with or slightly above areas of flood-plain alluvium of Recent age and separated from higher plains and residual 'islands' of older silt deposits by an erosional scrap 10 BI0033113 Baird Inlet Unconsolidated113 1130 Qb Beach deposits Quaternary NG002114 Nushagak Bay Unconsolidated115 1150 Qb Beach deposits Quaternary NG007702 Nushagak Bay Unconsolidated115 1150 Qb Older beach deposits Quaternary Older raised beach ridges on mainland along Kuskokwim Bay. Derived from interpretation of topographic maps and Google Earth image. Deposits are locally transitional to undivided surficial deposits, alluvial deposits, and locally may constitute the mate KB0033115 Kuskokwim Bay Unconsolidated115 1150 Qb Older beach deposits Quaternary Older raised beach ridges on mainland along Kuskokwim Bay. Derived from interpretation of topographic maps and Google Earth image. Deposits are locally transitional to undivided surficial deposits, alluvial deposits, and locally may constitute the mate BI0033115 Baird Inlet Unconsolidated115 1150 Qb Older beach deposits Quaternary Older raised beach ridges on mainland along Kuskokwim Bay. Derived from interpretation of topographic maps and Google Earth image. Deposits are locally transitional to undivided surficial deposits, alluvial deposits, and locally may constitute the mate NI0044115 Nunivak Island Unconsolidated115 1150 Qes Raised estuarine deposits Quaternary NG002116 Nushagak Bay Unconsolidated116 1160 Qes Raised estuarine deposits Quaternary NG007704 Nushagak Bay Unconsolidated116 1160 Qes Raised estuarine deposits Quaternary GO0066116 Goodnews Bay Unconsolidated116 1160 Qmt Raised estuarine deposits Quaternary Underlain be older estuarine and alluvial deposits NG007706 Nushagak Bay Unconsolidated117 1170 Qmt Marine terrace Quaternary Raised surface underlain by a varity of unconsolidated deposits, especially including older beach, estuarine, alluvial, and probably glacial deposits KB0033117 Kuskokwim Bay Unconsolidated117 1170 Qmt Marine terrace Quaternary Raised surface underlain by a varity of unconsolidated deposits, especially including older beach, estuarine, alluvial, and probably glacial deposits BI0033117 Baird Inlet Unconsolidated117 1170 Qb Older beach deposits Quaternary Older raised beach ridges eroded to constitute raised marine terraces on mainland along Kuskokwim Bay. Derived from interpretation of topographic maps and Google Earth image. Deposits are locally transitional to undivided surficial deposits, alluvial d NI0044117 Nunivak Island Unconsolidated117 1170 Late alluvial sediments, mostly sand, St. Paul Island Quaternary Late alluvial sediments, mostly sand. In most places, the sand is loose and moves with the wind. Along the north shore of St. Paul Island, impressive dunes are formed PI002120 Pribilof Islands Unconsolidated119 1190 Qd Eolian deposits Holocene Dunes (fine-grained sand). NG002110 Nushagak Bay Unconsolidated120 1200 Qd Eolian deposits Holocene Dunes (fine-grained sand). NG007710 Nushagak Bay Unconsolidated120 1200 Qs Silt deposits Quaternary Light- to dark-gray silt and sandy silt GO008722 Goodnews Bay Unconsolidated121 1210 Qsd Silt deposits Quaternary Inferred by extrapolation from adjacent Bethel and Goodnews Bay quadrangles. Chiefly light- to dark-gray silt and sandy silt containing abundant permafrost. Deposits become sandier with depth and locally contain pebbles and wood fragments. Deposits arOrganic muck containing mammoth remains and nonmarine gastropods occur locally near top of deposits KB0033121 Kuskokwim Bay Unconsolidated121 Q 1210 Qsd Silt deposits Quaternary Inferred by extrapolation from adjacent Bethel and Goodnews Bay quadrangles. Chiefly light- to dark-gray silt and sandy silt containing abundant permafrost. Deposits become sandier with depth and locally contain pebbles and wood fragments. Deposits arOrganic muck containing mammoth remains and nonmarine gastropods occur locally near top of deposits BI0033121 Baird Inlet Unconsolidated121 1210 Qs Silt deposits Quaternary Chiefly light- to dark-gray silt and sandy silt containing abundant permafrost. Deposits become sandier with depth and locally contain pebbles and wood fragments. Deposits are probably of nonmarine fluvial origin but may include eolian and marine membeOrganic muck containing mammoth remains and nonmarine gastropods occur locally near top of deposits BH0043122 Bethel Unconsolidated121 1210 Qg Glacial Deposits Holocene and Pleistocene Glacial drift deposited during the last three glacial advances. Sand, gravel, and boulders. Includes moraines. Also includes colluvium, talus, landslide debris, alluvium, and local silt. GO002106 Goodnews Bay Unconsolidated125 1250 Qg Glacial Deposits Holocene and Pleistocene Glacial drift deposited during the last three glacial advances. Sand, gravel, and boulders. Includes moraines. Also includes colluvium, talus, landslide debris, alluvium, and local silt. HG002106 Hagemeister IslandUnconsolidated125 1250 Qg Glacial Deposits Holocene and Pleistocene Glacial drift deposited during the last three glacial advances. Sand, gravel, and boulders. Includes moraines. Also includes colluvium, tallus, landslide debris, alluvium, and local silt. NG002106 Nushagak Bay Unconsolidated125 1250 Qt Glacial till Pleistocene Unconsolidated glacial till; ground lateral and end moraines BH002125 Bethel Unconsolidated125 1250 Qd Glacial drift Quaternary Poorly to well-sorted silt, sand, gravel, and boulders; stipple indicates well-defined end and lateral moraines HG005625 Hagemeister IslandUnconsolidated125 1250 Qg Glacial Deposits Holocene and Pleistocene Glacial drift deposited during the last three glacial advances. Sand, gravel, and boulders. Includes moraines. Also includes colluvium, tallus, landslide debris, alluvium, and local silt. NG007703 Nushagak Bay Unconsolidated125 1250 Qd Glacial drift Quaternary Poorly to well-sorted silt, sand, gravel, and boulders; stipple indicates well-defined end and lateral moraines GO008725 Goodnews Bay Unconsolidated125 1250 Qd Glacial drift Quaternary Poorly to well-sorted silt, sand, gravel, and boulders GO006825 Goodnews Bay Unconsolidated125 1250 Qd Glacial drift Quaternary Chiefly unsorted and poorly sorted sand, gravel, and boulders comprising various types of ice-contact and glaciofluviatile deposits; small areas of glacial outwash, colluvium, and alluvium included with unit. BH0043135 Bethel Unconsolidated125 1250 Qm Morainal ridges Quaternary Morainal ridges of all ages; however most are probably associated with Late Wisconsin events. Topographic map interpretation enhanced by data from Warren Coonrad NG007700 Nushagak Bay Unconsolidated135 1350 Qo Outwash deposits Quaternary Most probably associated with Late Wisconsin events NG002140 Nushagak Bay Unconsolidated140 1400 Qo Outwash deposits Quaternary Poorly to well-sorted silt, gravel, and boulders in terraces and outwash fan-plains HG005640 Hagemeister IslandUnconsolidated140 1400 Qo Outwash deposits Quaternary Poorly to well-sorted silt, gravel, and boulders in terraces and outwash fan-plains GO008740 Goodnews Bay Unconsolidated140 1400 Qo Outwash deposits Quaternary Most probably associated with Late Wisconsin events NG007740 Nushagak Bay Unconsolidated140 1400 Qo Outwash deposits Quaternary Poorly to well-sorted sand and gravel with some silt and a few boulders, constituting terraces and outwash-fan plains. BH0043140 Bethel Unconsolidated140 1400 QTs Semiconsolidated marine beach deposits Pleistocene or Pliocene Semiconsolidated marine beach deposits. Poorly bedded, soft, pebbly siltstones cap volcanic rock sea cliffs. shallow marine fossils of Plio-Pleistocene age HG002112 Hagemeister IslandSedimentary 282 2820 Pyroclastic deposits, St. Paul Island Quaternary Pyroclastic deposits, largely basaltic tuff PI002310 Pribilof Islands Igneous 310 3100 Pyroclastic deposits, Otter Island Quaternary Pyroclastic deposits PI002311 Pribilof Islands Igneous 310 3100 Tuff, St. George Island Quaternary Tuff PI002312 Pribilof Islands Igneous 310 3100 Pyroclastic deposits, St. George Island Quaternary Pyroclastic deposits, largely basaltic tuff PI002313 Pribilof Islands Igneous 310 3100 Pleistocene sediments, some fossiliferous, St. Paul Island Quaternary Pleistocene sediments, some fossiliferous. Polymictic, but composed primarily of basaltic boulders and clasts. Locally cross-bedded PI002291 Pribilof Islands Unconsolidated317 3170 Fossiliferous sediments, St. George Island Quaternary Fossiliferous sediments consisting of sand and yellow tuff containing rounded basalt pebbles. Sediemts overlie a glaciated surface of the peridotite upon which Pleistocene fossil shells have been cemented. The sediments are quite varied; however, a basaPelecypods and gastropods of Pleistocene age PI002292 Pribilof Islands Unconsolidated317 3170 Sedimentary deposits, Otter Island Quaternary Sediments PI002293 Pribilof Islands Igneous 317 3170 Qkn1 Alkalic basalt of Karon Lake Pleistocene and Holocene Alkalic basalt of Karon Lake; cinder cones, flows, and tephra; normally polarized rocks of Brunhes polarity epoch NI003120 Nunivak Island Igneous 320 3200 Qkn1 Alkalic basalt of Karon Lake Pleistocene and Holocene Alkalic basalt of Karon Lake; cinder cones, flows, and tephra; normally polarized rocks of Brunhes polarity epoch CM003120 Cape Mendenhall Igneous 320 3200 Qtb Basalt of Togiak River Valley Pleistocene Fine- and medium-grained, columnar jointed tholeiite and alkali-olivine basalt flows on the floor of the broad Togiak River Valley. K/Ar age of 0.758 +/- 0.2 m.y. GO002110 Goodnews Bay Igneous 330 3300 Qtb Basalt of Togiak River Valley Pleistocene Fine- and medium-grained, columnar jointed tholeiite and alkali-olivine basaltflows on the floor of the broad Togiak River Valley. K/Ar age of 0.758 +/- 0.2 m.y. HG002110 Hagemeister IslandIgneous 330 3300 Qmn1 Tholeiitic basalt of Mekoryuk Pleistocene and Holocene Tholeiitic basalt of Mekoryuk; massive, columnar-jointed flows; normally polarized rocks of Brunhes polarity epoch NI003130 Nunivak Island Igneous 330 3301 Qmn1 Tholeiitic basalt of Mekoryuk Pleistocene and Holocene Tholeiitic basalt of Mekoryuk; massive, columnar-jointed flows; normally polarized rocks of Brunhes polarity epoch CM003130 Cape Mendenhall Igneous 330 3301 Qb Basalt Pleistocene Unaltered olivine tholeiite basalt flows having diktytaxitic texture. Contains olivine, subophitic clinopyroxene, plagioclase and iron oxides with sparse interstitial volcanic glass. Whole rock K/Ar age of 0.418+0.016 Ma BH002300 Bethel Igneous 330 3300 Qb Quaternary basalt (Togiak basalt of Hoare and Coonrad, 1980) Quaternary Subaerial alkali olivine basalt flows, columnar, jointed with ropy tops; includes minor interflow tuffs and breccias. Generally nonporphyritic, dark-gray to black rock with fine microcrysts of labradorite, augite, olivine, and accessory magnetite, with d Whole-rock K-Ar determination on lower unit yields 0.78 +/- 0.2 m.y. GO005500 Goodnews Bay Igneous 330 3300 Qb Quaternary basalt (Togiak basalt of Hoare and Coonrad, 1980) Quaternary Subaerial alkali olivine basalt flows, columnar, jointed with ropy tops; includes minor interflow tuffs and breccias. Generally nonporphyritic, dark-gray to black rock with fine microcrysts of labradorite, augite, olivine, and accessory magnetite, with d Whole-rock K-Ar determination on lower unit yields 0.78 +/- 0.2 m.y. HG003500 Hagemeister IslandIgneous 330 3300 QTb Basalt Quaternary or Tertiary (early Pleistocene or late Pliocene Highly vesicular and scoriaceous black olivine basalt flows showing little or no alteration; matrix chiefly volcanic glass. BH0043350 Bethel Igneous 330 3300 Qmr1 Tholeiitic basalt of Mekoryuk Pleistocene and Holocene Tholeiitic basalt of Mekoryuk; massive, columnar-jointed flows; reversely polarized rocks of Matuyama polarity epoch NI003131 Nunivak Island Igneous 350 3502 Qmr1 Tholeiitic basalt of Mekoryuk Pleistocene and Holocene Tholeiitic basalt of Mekoryuk; massive, columnar-jointed flows; reversely polarized rocks of Matuyama polarity epoch CM003131 Cape Mendenhall Igneous 350 3502 Qmn2 Tholeiitic basalt of Mekoryuk Pleistocene and Holocene Tholeiitic basalt of Mekoryuk; massive, columnar-jointed flows; normally polarized rocks of Matuyama polarity epoch NI003132 Nunivak Island Igneous 350 3503 Qmn3 Tholeiitic basalt of Mekoryuk Pleistocene and Holocene Tholeiitic basalt of Mekoryuk; massive, columnar-jointed flows; normally polarized rocks of Matuyama polarity epoch NI003133 Nunivak Island Igneous 350 3503 Basaltic flows, St. Paul Island Quaternary Basaltic flows and sills. Flows range in thickness from 20 cm to 7 m or more. Some are vesicular, some dense. Compositionally they are basalt and olivine hylobasanite, alkalic PI002330 Pribilof Islands Igneous 450 4500 Basaltic flows, St. George Island Quaternary Basaltic flows and sills. Flows range in thickness from 20 cm to 7 m or more. Some are vesicular, some dense. Compositionally they are basalt and olivine basanite, alkalic PI002331 Pribilof Islands Igneous 450 4500 Hylobasanitic flows, Otter Island Quaternary Lava flows of hylobasanite at leaat 325 feet thick, alkalic PI002332 Pribilof Islands Igneous 450 4500 QTv Mafic volcanic rocks Quaternary/Tertiary Basalt lava flows and cinder cones. BI0025 Baird Inlet Igneous 450 4500 QTv Mafic volcanic rocks Quaternary/Tertiary Basalt lava flows and cinder cones. NI0025 Nunivak Island Igneous 450 4500 QTv Mafic volcanic rocks Quaternary/Tertiary Basalt lava flows and cinder cones. CM0025 Cape Mendenhall Igneous 466 4660 Qkr1 Alkalic basalt of Karon Lake Pleistocene and Holocene Alkalic basalt of Karon Lake; cinder cones, flows, and tephra; reversely polarized rocks of Matuyama (?) polarity epoch NI003121 Nunivak Island Igneous 466 4660 Qkr1 Alkalic basalt of Karon Lake Pleistocene and Holocene Alkalic basalt of Karon Lake; cinder cones, flows, and tephra; reversely polarized rocks of Matuyama (?) polarity epoch CM003121 Cape Mendenhall Igneous 466 4660 Qkn2 Alkalic basalt of Karon Lake Pleistocene and Holocene Alkalic basalt of Karon Lake; cinder cones, flows, and tephra; normally polarized rocks of Matuyama (?) polarity epoch NI003122 Nunivak Island Igneous 466 4660 Qkn2 Alkalic basalt of Karon Lake Pleistocene and Holocene Alkalic basalt of Karon Lake; cinder cones, flows, and tephra; normally polarized rocks of Matuyama (?) polarity epoch CM003122 Cape Mendenhall Igneous 466 4660 Ta Alkalic basalt of Ahzwiryuk Bluff Tertiary, Pliocene Alkalic basalt of Ahzwiryuk Bluff; nubbly mottled flows and pyroclastic ejecta; includes both normally and reversely polarized rocks older than Gauss polarity epoch NI003140 Nunivak Island Igneous 1023 Tbn1 Tholeittic basalt of Binakslit Bluff Tertiary, Pliocene Tholeittic basalt of Binakslit Bluff; massive, columnar-jointed flows; normally polarized flows of Gauss polarity epoch NI003141 Nunivak Island Igneous 1024 Tbn1 Tholeittic basalt of Binakslit Bluff Tertiary, Pliocene Tholeittic basalt of Binakslit Bluff; massive, columnar-jointed flows; normally polarized flows of Gauss polarity epoch CM003141 Cape Mendenhall Igneous 1024 Tb Tholeittic basalt of Binakslit Bluff Tertiary, Pliocene Tholeittic basalt of Binakslit Bluff; massive, columnar-jointed flows; includes both normally and reversely polarized flows older than Gauss polarity epoch NI003142 Nunivak Island Igneous 1024 Tif Felsic intrusive rocks Tertiary Light-colored, fine-grained, commonly porphyritic felsic intrusive rocks. Chiefly rhyolitic to dacitic dikes and sills K/Ar age of 13 +/- 0.5 m.y. from biotite. GO002160 Goodnews Bay Igneous 1053 Tif Felsic intrusive rocks Tertiary Light-colored, fine-grained, commonly porphyritic felsic intrusive rocks. Chiefly rhyolitic to dacitic dikes and sills K/Ar age of 13 +/- 0.5 m.y. from biotite. HG002160 Hagemeister IslandIgneous 1053 Tif Felsic intrusive rocks Tertiary Light-colored, fine-grained, commonly porphyritic felsic intrusive rocks. Chiefly rhyolitic to dacitic dikes and sills K/Ar age of 13 +/- 0.5 m.y. from biotite. NG002160 Nushagak Bay Igneous 1053 Tr Tertiary rhyolite Tertiary Abundant sills and dikes cutting Kus and Jln in vicinity of Nunavarchak Lake (only largest body shown). Consists of cream-colored, often iron-stained, aphanitic to porphyritic rhyolite to dacite. Phenocrysts are quartz, plagioclase, orthoclase, and acces Yields a K-Ar biotite age of 13.0 +/- 0.5 m.y.; however, its association with feeder dikes of Upper Cretaceous volcanic rocks suggest true intrusive age may be Late Cretaceous. GO005502 Goodnews Bay Igneous 1053 Tr Tertiary rhyolite Tertiary Abundant sills and dikes cutting Kus and Jln in vicinity of Nunavarchak Lake (only largest body shown). Consists of cream-colored, often iron-stained, aphanitic to porphyritic rhyolite to dacite. Phenocrysts are quartz, plagioclase, orthoclase, and acces Yields a K-Ar biotite age of 13.0 +/- 0.5 m.y.; however, its association with feeder dikes of Upper Cretaceous volcanic rocks suggest true intrusive age may be Late Cretaceous. HG003502 Hagemeister IslandIgneous 1053 Tr Tertiary rhyolite Tertiary Abundant sills and dikes cutting Kus and Jln in vicinity of Nunavarchak Lake (only largest body shown). Consists of cream-colored, often iron-stained, aphanitic to porphyritic rhyolite to dacite. Phenocrysts are quartz, plagioclase, orthoclase, and acces Yields a K-Ar biotite age of 13.0 +/- 0.5 m.y.; however, its association with feeder dikes of Upper Cretaceous volcanic rocks suggest true intrusive age may be Late Cretaceous. NG006502 Nushagak Bay Igneous 1053 Tnr Nukluk Volcanic Field; rhyolite Tertiary, Eocene Moderately altered rhyolite flows, domes, and ash-flow tuffs. Rhyolite of the main volcanic field contains phenocrysts of sanidine, riebeckitic amphibole, and rare quartz. Ar/Ar total-fusion age of 54.7+1.6 Ma from riebeckite BH0021110 Bethel Igneous 1110 Tnba Nukluk Volcanic Field; basalt and andesite Tertiary, Eocene Massive, columnar-jointed, basalt and subordinate andesite flows. Minor latite and dacite. Overlies Tnr in Fog River area. Elsewhere, interbedded. BH0021111 Bethel Igneous 1111 Tr Rhyolite and dacite tuff Tertiary Chiefly rhyolite and dacite welded tuff and tuff breccia and dark rhyolite vitrophyre in the northern part of map area. Chiefly light-colored rhyolite and dacite hypabyssal rocks in the southern part of the map area. May be extrusive and hypabyssal cog ST002101 Saint Matthew Igneous 1120 Aplite, St. George Island Quaternary Aplite granite dike intruding peridotite. Surface weathered before eruption of overlying basatic flows PI002400 Pribilof Islands Igneous 1301 TKst Swift Creek Volcanic Field; Rhyolite ash-flow tuff Early Tertiary and (or) Late Cretaceous Fresh to moderately altered, densely welded rhyolite ash-flow tuff. Chiefly black glassy vitrophyre. BH0021600 Bethel Igneous 1603 TKsr Swift Creek Volcanic Field; Rhyolite Early Tertiary and (or) Late Cretaceous Frost-riven rubble from single rhyolite dome(?) BH0021601 Bethel Igneous 1603 TKer Eek Volcanic Field; Rhyolite Paleocene and Cretaceous (?) Pale pink to orange rhyolite domes found as small knobs or large domical hills as large as 4 km in diameter with 300 to 500 m in relief. Whole rock K/Ar age of 62.5+1.9 Ma and 59.3+1.8 Ma BH0021603 Bethel Igneous 1603 TKtb Tulip Volcanic Field; Block and ash flow Early Tertiary and (or) Late Cretaceous One block and ash flow mapped in area. Broken blocks of dacite in an ashy matrix of the same lithology. Interpreted as a hot avalanche deposit formed during dome collapse. Dacite contains very coarse (up to 14 mm) phenocrysts. BH0021607 Bethel Igneous 1603 Tr Albite rhyolite Tertiary(?) Light- to medium-gray, fine-grained, porphyritic albite rhyolite, commonly shows well-developed flow structures. Forms small stock-like bodies, dikes, and sills. BH00431603Bethel Igneous 1603 TKtd Tulip Volcanic Field; Dacite and Andesite flows and Dacite tuff Early Tertiary and (or) Late Cretaceous Dacite and subordinate andesite flows and underlying dacite pyroclastic rocks. Flows crop out as columnar-jointed cliffs. BH0021604 Bethel Igneous 1604 TKsa Swift Creek Volcanic Field; Andesite flows Early Tertiary and (or) Late Cretaceous Columnar-jointed andesite flows capping small hills that overlie unit Ksl. BH0021602 Bethel Igneous 1605 TKea Eek Volcanic Field; Andesite flows and Porphyry Paleocene and Cretaceous (?) Small outcrops and columnar jointed andesite flows. Subordinate altered andesite porphyry. Minor basalt, andesite lithic tuff, and dacite. Ar/Ar total-fusion age of 59.5+12.3 Ma from plagioclase BH0021605 Bethel Igneous 1605 Tv Volcanic rocks middle to late Tertiary Chiefly black, porphyritic olivine basalt; includes some andesitic flows and water-laid tuff and a small amount of obsidian and siliceous tuff. Rocks are moderately folded and unconformable on steeply dipping rocks of Cretaceous age and older. BH00431004Bethel Igneous 1605 Tf Felsic rocks Tertiary(?) Pink and gray, fine-grained quartz-feldspar porphyry; locally shows flow structure. Possibly a felsic border facies of granitic rocks similar to felsic rocks associated with the Horn Mountain stock in the central Kuskokwim region (Cady, 1955). BH00431625Bethel Igneous 1625 Peridotite, St. George Island Quaternary? Peridotite, forms basement of island. Massive, originally was a dunite and now largely altered to serpentine and magnetite. The upper surface of the peridotite is an erosion surface, shows glacial striae, appears polished, and has a brownish-black varn PI002460 Pribilof Islands Igneous 1640 TKg Granitic rocks Tertiary and Cretaceous Fine-, medium-, and coarse-grained, light- to dark-gray, rarely pink plutonic granitic rocks. Chiefly quartz monzonite, granodiorite, and quartz diorite. K/Ar age range of 62.5 to 72.5 m.y. from biotite and hornblende GO002165 Goodnews Bay Igneous 1655 Kug Upper Cretaceous granitic plutons Late Cretaceous Medium-grained granitic plutonic rocks, ranging from quartz monzonite to granodiorite to diorite, with accessory biotite and (or) hornblende (Hoare and Coonrad, 1978a). Intrude a variety of units across map, with narrow biotite-hornblende hornfels zones. Age based on several K-Ar determinations. GO005542 Goodnews Bay Igneous 1655 Kug Upper Cretaceous granitic plutons Late Cretaceous Medium-grained granitic plutonic rocks, ranging from quartz monzonite to granodiorite to diorite, with accessory biotite and (or) hornblende (Hoare and Coonrad, 1978a). Intrude a variety of units across map, with narrow biotite-hornblende hornfels zones. Age based on several K-Ar determinations. HG003542 Hagemeister IslandIgneous 1655 TKif Fisher Dome and Marvel Creek plutons, undivided Early Tertiary and (or) Late Cretaceous Small intrusions of about 1 km (square). Hornblende-biotite granite and granodiorite porphyry. Randomly oriented euhedral brown hornblende, brown biotite, plagioclase, and resorbed quartz phenocrysts in a fine-grained aplitic matrix of quartz, plagiocl BH0021655 Bethel Igneous 1655 Tg Granitic rocks Tertiary(?) Pink, light- to dark-gray, fine- to coarse-grained granite, quartz monzonite, granodiorite, and diorite. BH00431655Bethel Igneous 1655 Tn Igneous rocks of Nayorurun River area Tertiary Intrusive-extrusive complex consisting of dikes, sills, and related tuffs and breccias in the Nayorurun River area. K/Ar age of 60.7 +/- 1.8 m.y. from biotite GO002162 Goodnews Bay Igneous 1656 Tial Aniak Lake pluton Tertiary, Paleocene Coarse-grained, porphyritic to seriate leucocratic biotite granite pluton 10 km (square) in area. Speckled texture with randomly oriented feldspar phenocrysts. Porphyritic rhyolite dikes common in the uppermost part of pluton and in surrounding biotite Ar/Ar total-fusion age of 60.8+1.8 Ma from biotite BH0021320 Bethel Igneous 1656 TKg Granitic rocks Tertiary and Cretaceous Fine-, medium-, and coarse-grained, light- to dark-gray, rarely pink plutonic granitic rocks. Chiefly quartz monzonite, granodiorite, and quartz diorite. Subdivision of granite from original Hoare and Coonrad (1978) unit. K/Ar age range of 62.5 to 72.5 m.y. from biotite and hornblende GO0066165 Goodnews Bay Igneous 1656 TKg Granitic rocks Tertiary and Cretaceous Fine-, medium-, and coarse-grained, light- to dark-gray, rarely pink plutonic granitic rocks. Chiefly quartz monzonite, granodiorite, and quartz diorite K/Ar age range of 62.5 to 72.5 m.y. from biotite and hornblende NG002165 Nushagak Bay Igneous 1657 Kug Upper Cretaceous granitic plutons Late Cretaceous Medium-grained granitic plutonic rocks, ranging from quartz monzonite to granodiorite to diorite, with accessory biotite and (or) hornblende (Hoare and Coonrad, 1978a). Intrude a variety of units across map, with narrow biotite-hornblende hornfels zones. Age based on several K-Ar determinations. NG006542 Nushagak Bay Igneous 1657 Kug Upper Cretaceous granitic plutons Late Cretaceous Medium-grained granitic plutonic rocks, ranging from quartz monzonite to granodiorite to diorite, with accessory biotite and (or) hornblende (Hoare and Coonrad, 1978a). Intrude a variety of units across map, with narrow biotite-hornblende hornfels zones. Age based on several K-Ar determinations. GO0066542 Goodnews Bay Igneous 1657 TKik Quartz monzonite of Kipchuk River Early Tertiary and (or) Late Cretaceous Small (< 1 km (square)) quartz monzodiorite intrusion in Kkcd of Kuskokwim Group causing contact metamorphism of Kkcd. Medium-grained, intergranular-textured biotite-augite quartz monzodiorite and quartz diorite. BH0021656 Bethel Igneous 1658 Kick Crooked Mountain pluton Late Cretaceous Large composite pluton with thin gabbro and diorite margin that partially rims and is intruded by massive core of biotite-hornblende granodiorite and granite. Dominantly augite-biotite-hornblende and (augite-) hornblende-biotite granodiorite, quartz mon Ar/Ar total-fusion age of 69.8+2.1 Ma from biotite BH0022460 Bethel Igneous 1658 Kicc Canyon Creek pluton Late Cretaceous Small (~1 km (square)), medium- to coarse-grained, intergranular to hypidiomorphic granular augite-biotite quartz diorite to hornblende-biotite granodiorite. Ar/Ar total-fusion age of 70.3+2.1 Ma from biotite BH0022461 Bethel Igneous 1658 TKg Granitic rocks Tertiary and Cretaceous Fine-, medium-, and coarse-grained, light- to dark-gray, rarely pink plutonic granitic rocks. Chiefly quartz monzonite, granodiorite, and quartz diorite. Subdivision of quartz monzonite from original Hoare and Coonrad (1978) unit. K/Ar age range of 62.5 to 72.5 m.y. from biotite and hornblende GO0066166 Goodnews Bay Igneous 1658 Tg Granodiorite Tertiary Fine-grained hornblende granodiorite K/Ar age of 62.2 +/- 2 Ma (recalc) from hornblende ST002102 Saint Matthew Igneous 1660 Ticp Cripple Mountain pluton Paleocene Elliptical, erosionally recessive pluton, 40 km (square). Coarse-grained, hypidiomorphic-granular hornblende-biotite granodiorite and granite, with lesser quartz monzodiorite and quartz monzonite. Aplite dikes near pluton margin. Ar/Ar total-fusion age of 62.2+1.9 Ma from biotite BH0021350 Bethel 1660 TKin North Fork pluton Early Tertiary and (or) Late Cretaceous Two phases: Main Felsic Phase is seriate to hypidiomorphic granular (augite-) hornblende-biotite quartz monzodiorite, granodiorite, and minor biotite granite. Aplite dikes are common. Mafic Phase is a coarse-grained cumulus-textured augite quartz gabb Ar/Ar total-fusion age of 64.3+1.9 Ma from biotite in Felsic Phase. BH0021660 Bethel Igneous 1660 TKg Granitic rocks Tertiary and Cretaceous Fine-, medium-, and coarse-grained, light- to dark-gray, rarely pink plutonic granitic rocks. Chiefly quartz monzonite, granodiorite, and quartz diorite. Subdivision of tonalite-monzonite from original Hoare and Coonrad (1978) unit. K/Ar age range of 62.5 to 72.5 m.y. from biotite and hornblende GO0066167 Goodnews Bay Igneous 1660 TKie Eek River pluton and related plutonic rocks Early Tertiary and (or) Late Cretaceous Sill 50 to 500 m thick crops out in discontinuous exposures over 10 km length cutting and contact-metamorphosing Kkcd of Kuskokwim Group north of Eek River. Dominantly medium- to coarse-grained, porphyritic to diabasic (hornblende) augite diorite, quart BH0021665 Bethel Igneous 1665 TKig Gemuk Mountain pluton Early Tertiary and (or) Late Cretaceous Elongate, north-trending, erosionally resistant, mafic to intermediate quartz gabbro to mafic granodiorite pluton, 25 km (square). Cuts and contact-metamorphoses units Kkv of Kuskokwim Group and Kvs of Togiak Terrane. BH0021666 Bethel Igneous 1665 TKip Mt. Plummer pluton Early Tertiary and (or) Late Cretaceous Medium- to coarse-grained, erosionally resistant, hypidiomorphic granular augite-biotite mafic granodiorite, quartz monzodiorite, and quartz diorite pluton. Intrudes and contact metamorphoses Kkmf, Kksh, and Kkcd of Kuskokwim group. K/Ar ages of 65.5+2.0 Ma and 66.6+2.0 Ma from biotite BH0021667 Bethel Igneous 1665 Kihd Hornblende diorite stocks and dikes Late Cretaceous Small, extensively altered, hornblende diorite stocks and dikes containing relict euhedral plagioclase. Ar/Ar total-fusion age of 68.0+2.0 Ma from hornblende BH0022490 Bethel Igneous 1665 TKg Granitic rocks Tertiary and Cretaceous Fine-, medium-, and coarse-grained, light- to dark-gray, rarely pink plutonic granitic rocks. Chiefly quartz monzonite, granodiorite, and quartz diorite. Subdivision of quartz diorite and diorite from original Hoare and Coonrad (1978) unit. K/Ar age range of 62.5 to 72.5 m.y. from biotite and hornblende GO0066168 Goodnews Bay Igneous 1665 Tim Mafic intrusive rocks Tertiary Dark-colored dikes and sills consisting of diabase, basalt, dioritic and gabbroic mafic intrusive rocks. K/Ar age of 64.6 +/- 2 m.y. from biotite GO002161 Goodnews Bay Igneous 1670 Tim Mafic intrusive rocks Tertiary Dark-colored dikes and sills consisting of diabase, basalt, dioritic and gabbroic mafic intrusive rocks K/Ar age of 64.6 +/- 2 m.y. from biotite HG002161 Hagemeister IslandIgneous 1670 TKg Gabbro Tertiary and Cretaceous Medium- to coarse-grained pyroxene gabbro dike (?) ST002202 Saint Matthew Igneous 1670 Tm Mafic rocks Tertiary(?) Gabbro, diabase, basalt, and biotite lamphrophyre in stocks, sills, and dikes. BH00431670Bethel Igneous 1670 Ks Sedimentary rocks of Summit Island Late Cretaceous (Maestrichtian (?)) Sedimentary rocks of Summit Island. A sequence of intertonguing nonmarine conglomerate, sandstone, shale, and carbonaceous mudstone containing abundant plant detritus and a few coal seams. Palynomorphs indicate Late Cretaceous GO002120 Goodnews Bay Sedimentary 1960 Ks Sedimentary rocks of Summit Island Late Cretaceous (Maestrichtian (?)) Sedimentary rocks of Summit Island. A sequence of intertonguing nonmarine conglomerate, sandstone, shale, and carbonaceous mudstone containing abundant plant detritus and a few coal seams. Palynomorphs indicate Late Cretaceous HG002120 Hagemeister IslandSedimentary 1960 Ks Sedimentary rocks of Summit Island Late Cretaceous (Maestrichtian (?)) Sedimentary rocks of Summit Island. A sequence of intertonguing nonmarine conglomerate, sandstone, shale, and carbonaceous mudstone containing abundant plant detritus and a few coal seams. Palynomorphs indicate Late Cretaceous NG002120 Nushagak Bay Sedimentary 1960 Kus Upper Cretaceous nonmarine clastic rocks (Summit Island Formation of Hoare and others, 1983) Late Cretaceous Nonmarine clastic rocks, moderately to well indurated, including (in order of abundance) black carbonaceous shale, fine to coarse sandstone, conglomerate, and thin coal seams. probable depositional contact on deformed older rocks not exposed. Divisible iFossils pollen suggest a Late Cretaceous, possibly Maestrichtian, age. GO005506 Goodnews Bay Sedimentary 1960 Kus Upper Cretaceous nonmarine clastic rocks (Summit Island Formation of Hoare and others, 1983) Late Cretaceous Nonmarine clastic rocks, moderately to well indurated, including (in order of abundance) black carbonaceous shale, fine to coarse sandstone, conglomerate, and thin coal seams. probable depositional contact on deformed older rocks not exposed. Divisible iFossils pollen suggest a Late Cretaceous, possibly Maestrichtian, age. HG003506 Hagemeister IslandSedimentary 1960 Kus Upper Cretaceous nonmarine clastic rocks (Summit Island Formation of Hoare and others, 1983) Late Cretaceous Nonmarine clastic rocks, moderately to well indurated, including (in order of abundance) black carbonaceous shale, fine to coarse sandstone, conglomerate, and thin coal seams. probable depositional contact on deformed older rocks not exposed. Divisible iFossils pollen suggest a Late Cretaceous, possibly Maestrichtian, age. NG006506 Nushagak Bay Sedimentary 1960 Kk Kuskokwim Group Cretaceous Kuskokwim Group. Marine sedimentary sequence consisting of graywacke, sandstone, conglomerate, siltstone, and shale. Early Cretaceous (Albian) age assigned from fossils found north of the map area. GO002121 Goodnews Bay Sedimentary 1970 Kkcf Kuskokwim Group; Chert-clast provenance rocks; Outer-fan turbidite facies Late Cretaceous (Turonian) Thin-bedded, fine-grained, quartzose sandstone and slate with lesser thin- and thick-bedded medium-grained sandstone. Age considered Turonian (Late Cretaceous) based on three megafossil collections BH0021970 Bethel Sedimentary 1970 Kkmf Kuskokwim Group; Mixed provenance rocks; Outer-fan turbidite facies Late Cretaceous (Turonian) Shale-rich sequence with lesser thin- to thick-bedded, medium-grained sandstone sections. Age considered Turonian (Late Cretaceous) based on two megafossil occurences BH0021972 Bethel Sedimentary 1970 Kkmc Kuskokwim Group; Mixed provenance rocks; Inner-fan-channel facies Late Cretaceous (Turonian) Mixed shale-rich and sandstone-rich sections, with coarse sandstone and pebbly sandstone in thick-bedded, amalgamated sequences with minor interbedded shale. Recovered fossils are nondiagnostic Cretaceous forms BH0021973 Bethel Sedimentary 1970 Kkv Kuskokwim Group; Volcanic provenance rocks Late Cretaceous (Turonian) Interbedded shale, siltstone, sandstone, and conglomerate composed of rounded clasts of volcanic, volcaniclastic, and plutonic rocks. Age considered Turonian (Late Cretaceous) based on megafossil occurences BH0021974 Bethel Sedimentary 1970 Kksh Kuskokwim Group; Shale and siltstone Late Cretaceous (Early Turonian and (or) Late Cenomanian) Dark-gray to black, finely laminated shale, siltstone and thin-bedded, very fine grained sandstone. Age constrained by megafossil occurances of late Cenomanian and (or) early Turonian age low in section and by overlying units of Turonian age BH0021975 Bethel Sedimentary 1970 Kks Kuskokwim Group, sedimentary rocks middle Late (Cenomaniam and Coniacian) to late Early Cretaceous (Albian)Chiefly consist of interbedded graywacke, siltstone, with lesser amounts of pebble grit and conglomerate and a small amount of coal. Well-indurated, commonly light- to dark-gray and weather brown. Vary from volcanic wacke to quartz-chert-feldspar-rich Fossils collected from basal zone are considered late Early Cretaceous (Albian) age and fossils from the upper zone considered early and middle Late Cretaceous (Cenomanian and Coniacian) BH00431970Bethel Sedimentary 1970 KCgg Gemuk Group, graywacke, siltstone, and conglomerate Early Cretaceous to Mississippian(?) Graywacke and conglomerate, massive, fine- to coarse-grained hard, dark-gray; massive and thin-bedded, light- to dark-gray and green lithic-feldspathic graywacke; massive varicolored argillite; banded slaty siltstone; minor amounts of limestone, calcareoFossils of early Cretaceous (Valanginian) and Late Jurassic age collected at widely scattered localities. BH00432830Bethel Sedimentary 1970 Kkcd Kuskokwim Group; Chert-clast provenance rocks; Deltaic facies Late Cretaceous (Turonian) Thick bedded quartzose sandstone, pebbly sandstone, and subordinate siltstone and shale. Re-assigned polygon from Hoare and Coonrad (1978) to subdivide Kuskokwim to match Box and others (1993) Age considered Turonian (Late Cretaceous) based on megafossil occurences GO006321 Goodnews Bay Sedimentary 1985 Kkcd Kuskokwim Group; Chert-clast provenance rocks; Deltaic facies Late Cretaceous (Turonian) Thick bedded quartzose sandstone, pebbly sandstone, and subordinate siltstone and shale. Age considered Turonian (Late Cretaceous) based on megafossil occurences BH0021971 Bethel Sedimentary 1985 Kkbc Kuskokwim Group; Basal Conglomerate Late Cretaceous (Cenomanian(?)) Pebble to boulder conglomerate, coarse sandstone, and minor interbedded medium-grained sandstone, siltstone, and shale. BH0021976 Bethel Sedimentary 1985 Kks Kuskokwim Group, sedimentary rocks, conglomerate facies middle Late (Cenomaniam and Coniacian) to late Early Cretaceous (Albian)Chiefly consists of conglomerate facies of interbedded graywacke and siltstone, with lesser amounts of pebble grit conglomerate and and a small amount of coal. Well-indurated, commonly light- to dark-gray and weather brown. Varies from volcanic wacke tFossils collected from basal zone are considered late Early Cretaceous (Albian) age and fossils from the upper zone considered early and middle Late Cretaceous (Cenomaniam and Coniacian) BH00431970Bethel Sedimentary 1985 Ks Graywacke-siltstone sequence Late Cretaceous(?) Volcanic graywacke, siltstone, and minor amounts of pebble conglomerate and coal; probably littoral marine. BI0029 Baird Inlet Sedimentary 2021 Ks Graywacke-siltstone sequence Late Cretaceous(?) Volcanic graywacke, siltstone, and minor amounts of pebble conglomerate and coal; probably littoral marine. NI0029 Nunivak Island Sedimentary 2021 Ks? Graywacke-siltstone sequence Late Cretaceous(?) Volcanic graywacke, siltstone, and minor amounts of pebble conglomerate and coal; probably littoral marine. NI00210 Nunivak Island Sedimentary 2021 Q Ks Sedimentary rocks Cretaceous Sedimentary rocks NI003150 Nunivak Island Sedimentary 2021 Kcg Graywacke and conglomerate Early Cretaceous Marine sedimentary unit consisting of hard graywacke, shaly and blocky siltstone, and local conglomerate. Rocks commonly calcareous. Buchia of Early Cretaceous (Valanginian age) GO002125 Goodnews Bay Sedimentary 2102 Kts Turbidite sandstone, conglomerate, and phyllite, Goodnews terrane Early Cretaceous Sandstone, sandy conglomerate, pebbly mudstone, siltstone, and shale with phyllitic fabric. Reassigned polygon from Hoare and Coonrad (1978) to match unit from Box and others (1993) to north. Pelecypod fossil collection of Valanginian, and of Late Jurassic and (or) Early Cretaceous, age GO006325 Goodnews Bay Sedimentary 2102 Kts Turbidite sandstone, conglomerate, and phyllite, Goodnews terrane Early Cretaceous Sandstone, sandy conglomerate, pebbly mudstone, siltstone, and shale with phyllitic fabric. Pelecypod fossil collection of Valanginian, and of Late Jurassic and (or) Early Cretaceous, age BH0022116 Bethel Sedimentary 2102 Kv Volcanic graywacke and argillite Cretaceous Thinly interbedded fine-grained graywacke and siliceous argillite thermally altered by granodiorite (Tg) ST0021301 Saint Matthew Sedimentary 2105 HFS Kb Graywacke of Buchia Ridge Early Cretaceous Marine sedimentary rocks of graywacke, siltstone, and conglomerate. Conglomerate, near the top of Buchia Ridge, contains local Buchia shell coquinas. Buchia and other "Fossils" show that it is Early Cretaceous in age (Valanginian and Hauterivian ages) GO002122 Goodnews Bay Sedimentary 2125 Klb Lower Cretaceous graywacke of Buchia Ridge Early Cretaceous Lithic sandstone, conglomerate, and shale at least 2-5 km thick (Hoare and Coonrad, 1983). Clastic rocks composed mostly of slaty volcaniclastic rock fragments, similar to Jurassic rocks to the southeast (Jln, Jmm). No paleocurrent data available. DivisiKlb1 preserves abundant Valanginian fauna; Klb2 yields rare Hauterivian ammonites. GO005508 Goodnews Bay Sedimentary 2125 Klg Limy grit and limestone Early Cretaceous Limy grit and limestone. Chiefly small, green, fine-grained angular rock fragments and minor round quartz pebbles cemented by gray bioclastic limestone consisting of tiny shell fragments. Coeval with the conglomeratic rocks of Buchia Ridge (Kb). Buchia of Early Cretaceous (Valanginian age) GO002123 Goodnews Bay Sedimentary 2150 Kts Tuff and sedimentary rocks Early Cretaceous Thick, varied assemblage of andesitic, commonly laumontitized, tuffs, sedimentary rocks, and a few flows. Buchia of Early Cretaceous (Valanginian age) Radiolaria of Early Cretaceous age GO002124 Goodnews Bay Sedimentary 2180 Kts Tuff and sedimentary rocks Early Cretaceous Thick, varied assemblage of andesitic, commonly laumontitized, tuffs, sedimentary rocks, and a few flows. Buchia of Early Cretaceous (Valanginian age) Radiolaria of Early Cretaceous age HG002124 Hagemeister IslandSedimentary 2180 Kvs Togiak Terrane; Marine volcaniclastic sandstone, conglomerate, shale, and interbedded tuff Early Cretaceous Thin- to thick-bedded, green tuffaceous sandstone, siltstone, argillite, conglomerate, tuff, and tuffaceous chert. Early Cretaceous pelecypods and radiolarians BH0022180 Bethel Sedimentary 2180 KCgg Gemuk Group, graywacke, siltstone, and conglomerate Early Cretaceous to Mississippian(?) Graywacke and conglomerate, massive, fine- to coarse-grained hard, dark-gray; massive and thin-bedded, light- to dark-gray and green lithic-feldspathic graywacke; massive varicolored argillite; banded slaty siltstone; minor amounts of limestone, calcareoFossils of early Cretaceous (Valanginian) and Late Jurassic age collected at widely scattered localities. BH00432830Bethel Sedimentary 2180 KCgg Gemuk Group, graywacke, siltstone, and conglomerate Early Cretaceous to Late Jurassic Graywacke and conglomerate, massive, fine- to coarse-grained hard, dark-gray; massive and thin-bedded, light- to dark-gray and green lithic-feldspathic graywacke; massive varicolored argillite; banded slaty siltstone; minor amounts of limestone, calcareoFossils of early Cretaceous (Valanginian) and Late Jurassic age collected at widely scattered localities. BH00432831Bethel Sedimentary 2180 Ktr Tulip Volcanic Field; Rhyolite domes and flows Late Cretaceous Rhyolite domes and flows found as small knobs or hills. Moderately to severely altered. BH0022210 Bethel Igneous 2210 Kvkr Kipchuk Volcanic Field; Rhyolite domes and flows Late Cretaceous Moderately to severely altered, white to orange, platy rhyolite domes and flows, and minor rhyolite breccia. Lithologically similar to Ktr. BH0022265 Bethel Igneous 2210 ALT Tv Volcanic rocks and volcanogenic deposits Early Tertiary Mostly andesitic and trachytic tuffs, breccias, and flows. Lesser basaltic andesite and diabase and fine- to medium-grained volcanogenic sediments HG002115 Hagemeister IslandIgneous 2260 Tv Volcanic rocks and volcanogenic deposits Early Tertiary Mostly andesitic and trachytic tuffs, breccias, and flows. Lesser basaltic andesite and diabase and fine- to medium-grained volcanogenic sediments NG002115 Nushagak Bay Igneous 2260 TKm Mafic flows and volcaniclastic deposits Early Tertiary to Late Cretaceous Flat-lying to gently dipping mafic flows of andesite and basalt, and volcaniclastic deposits of andesitic and basaltic tuff and conglomerate K/Ar age of 78.7 +/- 2 and 66.4+/- 2 m.y. from whole rock samples of basalt ST002201 Saint Matthew Sedimentary 2260 Kuv Upper Cretaceous volcanic rocks Late Cretaceous Moderately to steeply dipping, fresh to weakly altered porphyritic andesite flows and interbedded sandy to bouldery volcaniclastic rocks. Phenocrysts are plagioclase, clinopyroxene, orthopyroxene, pseudomorphic talc after olivine, and accessory magnetite Four whole-rock K-Ar determinations yield Late Cretaceous ages. GO005504 Goodnews Bay Igneous 2260 Kuv Upper Cretaceous volcanic rocks Late Cretaceous Moderately to steeply dipping, fresh to weakly altered porphyritic andesite flows and interbedded sandy to bouldery volcaniclastic rocks. Phenocrysts are plagioclase, clinopyroxene, orthopyroxene, pseudomorphic talc after olivine, and accessory magnetite Four whole-rock K-Ar determinations yield Late Cretaceous ages. HG003504 Hagemeister IslandIgneous 2260 Kuv Upper Cretaceous volcanic rocks Late Cretaceous Moderately to steeply dipping, fresh to weakly altered porphyritic andesite flows and interbedded sandy to bouldery volcaniclastic rocks. Phenocrysts are plagioclase, clinopyroxene, orthopyroxene, pseudomorphic talc after olivine, and accessory magnetite Four whole-rock K-Ar determinations yield Late Cretaceous ages. NG006504 Nushagak Bay Igneous 2260 Kvk6 Kipchuk Volcanic Field; Andesite and Basalt flows Late Cretaceous (Maastrichtian) Porphyritic plagioclase-pyroxene-olivine andesite flows and flow breccias, minor interbedded flows of olivine basalt, and black andesite tuff. Ar/Ar total-fusion age of 69.5+2.1 Ma from biotite BH0022271 Bethel Igneous 2260 Kvk3 Kipchuk Volcanic Field; Andesite flows Late Cretaceous Porphyritic, propylitically altered, one- and two-pyroxene andesite lava flows. Minor olivine basalt flows, dacite flows, and andesite tuff. BH0022274 Bethel Igneous 2260 Kvk1 Kipchuk Volcanic Field; Basal Andesite flows Late Cretaceous Light-gray to tan, sugary textured, fine-grained andesite flows with well-developed flow banding and irregular platy fracture. BH0022276 Bethel Igneous 2260 Ksl Swift Creek Volcanic Field; Lithic air-fall tuff Late Cretaceous (Campanian) Moderately altered, andesitic lithic air-fall tuffs, tuff breccias, and altered andesite flows. Varies from coarse-grained lithic tuff breccia with clasts as large as 2 m in diameter to ash beds containing lithic fragments less than 0.6 cm in diameter. Whole rock Ar /Ar total-fusion age of 74.3+2.2 Ma BH0022270 Bethel Igneous 2261 Kvk5 Kipchuk Volcanic Field; Fine-grained tuff, crystal-vitric tuff, and tuffaceous sandstone Late Cretaceous (Maestrichtian) Lacustrine, fluvial, and air-fall tuff. Very fine- to fine-grained tuffs that are finely laminated. Air-fall tuff is fine- to medium-grained with well developed bedding. BH0022272 Bethel Igneous 2261 Kvk4 Kipchuk Volcanic Field; Upper black Andesite lithic tuff Late Cretaceous (Maastrichtian) Black, densely welded andesite tuff exposed in low hills and ridges. Whole rock K/Ar ages of 69.0+2.1 Ma and 71.4+2.1 Ma BH0022273 Bethel Igneous 2261 Kvk2 Kipchuk Volcanic Field; Lower black Andesite lithic tuff Late Cretaceous Massive, dark, fine-grained tuff having black opaque vitroclastic groundmass and abundant lithic fragments of volcanic rocks and lesser sandstone and shale. BH0022275 Bethel Igneous 2261 Ki Intermediate and silicic pyroclastic deposits Late Cretaceous Intermediate and silicic pyroclastic deposits including: dacite, andesite, and rhyolite nonwelded tuff breccia and crystal tuff, dacite and rhyolite welded tuff, massive dacite breccia (lahar?), fine ash-fall tuff, volcanic conglomerate, and andesite andPollen assemblages from carbonaceous tuffs K/Ar age of 74.1 +/- 2 and 74.4+/- 2 m.y. from biotite and hornblende ST002302 Saint Matthew Igneous 2265 Ki Intermediate and silicic pyroclastic deposits Late Cretaceous Intermediate and silicic pyroclastic deposits including: dacite, andesite, and rhyolite nonwelded tuff breccia and crystal tuff, dacite and rhyolite welded tuff, massive dacite breccia (lahar?), fine ash-fall tuff, volcanic conglomerate, and andesite andPollen assemblages from carbonaceous tuffs K/Ar age of 74.1 +/- 2 and 74.4+/- 2 m.y. from biotite and hornblende ST0021302 Saint Matthew Igneous 2265 HFS Ksp Serpentinite Late Cretaceous Small, pervasively slickensided bodies of serpentinite, serpentinite-matrix melange, and silica-carbonate altered serpentinite. BH0022510 Bethel Igneous 2510 s Serpentine Tertiary(?) Fibrous pale-green and massive black serpentine forming a small intrusive body north of mouth of Crooked Creek. BH00432510Bethel Igneous 2510 Kinc Nyac, Bonanza Creek, and Columbia Creek plutons, undivided Early Cretaceous Rock is pale-pink weathering light-gray, coarse-grained porphyritic to seriate hornblende-biotite and biotite-hornblende granite, quartz monzonite, and lesser granodiorite and quartz-monzodiorite. Nyac (~200 km) is crudely concentrically zoned from horn Nyac: K/Ar age of 101.1+3.0 Ma from hornblende; 108.5+3.3 Maÿand 120.0+3.6 Ma from biotite; and U/Pb age of 104 to 129 Ma from zircon. Bonanza Creek: Ar/Ar total-fusion age of 110+3.3 Ma from biotite. Columbia Creek: K/Ar age of 115.0+3.5 Ma from biotiBH0022530 Bethel Igneous 2530 KJc Togiak Terrane; Argillite and tuffaceous chert Early Cretaceous and (or) Late Jurassic Thin-bedded green to brown argillite with occasional 1- to 4-cm thick tuffaceous chert, siltstone, and fine-grained tuff interbeds. Late Jurassic and (or) Early Cretaceous age from poorly preserved radiolarians BH0022810 Bethel Sedimentary 2832 KJba Basaltic and Andesitic lava flows, Nyac terrane Early Cretaceous and (or) Late Jurassic Basaltic and andesitic lava flows. BH0022871 Bethel Sedimentary 2870 KJvs Volcanic and sedimentary rocks Early Cretaceous to Middle Jurassic Thick marine unit consisting of volcanic and sedimentary rocks. Volcanic rocks range in composition from mafic pillow basalts to more abundant andesitic and trachytic flows, tuffs, and breccias. Interbedded with the volcanic rocks are tuffaceous siltstRadiolaria of Late Jurassic to Early Cretaceous age, and fragmentary ammonites of Jurassic age. GO002127 Goodnews Bay Sedimentary 2872 KJvs Volcanic and sedimentary rocks Early Cretaceous to Middle Jurassic Thick marine unit consisting of volcanic and sedimentary rocks. Volcanic rocks range in composition from mafic pillow basalts to more abundant andesitic and trachytic flows, tuffs, and breccias. Interbedded with the volcanic rocks are tuffaceous siltstRadiolaria of Late Jurassic to Early Cretaceous age, and fragmentary ammonites of Jurassic age. HG002127 Hagemeister IslandSedimentary 2872 KJvs Volcanic and sedimentary rocks Early Cretaceous to Middle Jurassic Thick marine unit consisting of volcanic and sedimentary rocks. Volcanic rocks range in composition from mafic pillow basalts to more abundant andesitic and trachytic flows, tuffs, and breccias. Interbedded with the volcanic rocks are tuffaceous siltstRadiolaria of Late Jurassic to Early Cretaceous age, and fragmentary ammonites of Jurassic age. BH003127 Bethel Sedimentary 2872 TJih Hypabyssal felsic intrusive rocks Early Tertiary (?), Cretaceous, and Jurassic Highly altered rhyolite and dacite porphyries. BH0022885 Bethel Igneous 2885 KJb Togiak Terrane; Pillow basalt Early Cretaceous and (or) Late Jurassic Very altered pillow basalt sequence. Interbedded with argillite and thin-bedded chert of KJc. Radiolarian fauna in interbedded KJc BH0022890 Bethel Sedimentary 2890 TJis Slate Creek pluton Early Tertiary (?), Cretaceous, and Jurassic Erosionally neutral, medium-grained hypidiomorphic-granular, mafic hornblende tonalite and granodiorite pluton, less than 2 km (square). BH0022905 Bethel Igneous 2900 Jvs Togiak Terrane; Marine volcaniclastic sandstone, conglomerate, and argillite Jurassic Turbidite-facies volcaniclastic strata, locally as coarse as fine-grained pebble conglomerate BH0023121 Bethel Sedimentary 3005 KCgg Gemuk Group, graywacke, siltstone, and conglomerate Early Cretaceous to Late Jurassic Graywacke and conglomerate, massive, fine- to coarse-grained hard, dark-gray; massive and thin-bedded, light- to dark-gray and green lithic-feldspathic graywacke; massive varicolored argillite; banded slaty siltstone; minor amounts of limestone, calcareoFossils of early Cretaceous (Valanginian) and Late Jurassic age collected at widely scattered localities. BH00432830Bethel Sedimentary 3005 KCgg Gemuk Group, graywacke, siltstone, and conglomerate Early Cretaceous to Late Jurassic Graywacke and conglomerate, massive, fine- to coarse-grained hard, dark-gray; massive and thin-bedded, light- to dark-gray and green lithic-feldspathic graywacke; massive varicolored argillite; banded slaty siltstone; minor amounts of limestone, calcareoFossils of early Cretaceous (Valanginian) and Late Jurassic age collected at widely scattered localities. BH00432832Bethel Sedimentary 3005 Jvc Volcaniclastic conglomerate, sandstone, and shale, Nyac terrnae Late and Middle Jurassic Epiclastic sequence of tuffaceous marine sandstone, shale, and conglomerate with minor interbedded basaltic and andesitic lava flows Marine pelecypods of Bajocian age (Middle Jurassic); Marine pelecypods of Tithonian age (Late Jurassic) BH0023120 Bethel Sedimentary 3120 Ja Togiak Terrane; Marine arkosic sandstone and argillite Jurassic Turbidite-facies arkosic sandstone and shale BH0023130 Bethel Sedimentary 3130 Jk Graywacke of Kulukak Bay Middle to early Late Jurassic A thick marine sedimentary unit referred to as "Weary graywacke" by Hoare and others, 1975. Consists of very hard graywacke and siltstone with local conglomerate. Buchia, Inoceramus, belemnites, and rare ammonite fragments ranging from Middle to early Late Jurassic age. GO002130 Goodnews Bay Sedimentary 3150 Jk Graywacke of Kulukak Bay Middle to early Late Jurassic A thick marine sedimentary unit referred to as "Weary graywacke" by Hoare and others, 1975. Consists of very hard graywacke and siltstone with local conglomerate. Buchia, Inoceramus, belemnites, and rare ammonite fragments ranging from Middle to early Late Jurassic age. HG002130 Hagemeister IslandSedimentary 3150 Jk Graywacke of Kulukak Bay Middle to early Late Jurassic A thick marine sedimentary unit referred to as "Weary graywacke" by Hoare and others, 1975. Consists of very hard graywacke and siltstone with local conglomerate. Buchia, Inoceramus, belemnites, and rare ammonite fragments ranging from Middle to early Late Jurassic age. NG002130 Nushagak Bay Sedimentary 3150 Jk Graywacke of Kulukak Bay Middle to early Late Jurassic A thick marine sedimentary unit referred to as "Weary graywacke" by Hoare and others, 1975. Consists of very hard graywacke and siltstone with local conglomerate. Locally hornfelsed Buchia, Inoceramus, belemnites, and rare ammonite fragments ranging from Middle to early Late Jurassic age. NG00220130Nushagak Bay Sedimentary 3150 HFS Jmm Middle and Upper Jurassic turbidites of Metervik Bay Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). GO005510 Goodnews Bay Sedimentary 3151 Jmm Middle and Upper Jurassic turbidites of Metervik Bay Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). HG003510 Hagemeister IslandSedimentary 3151 Jmm Middle and Upper Jurassic turbidites of Metervik Bay Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). NG006510 Nushagak Bay Sedimentary 3151 Jmm1 Middle and Upper Jurassic turbidites of Metervik Bay, conglomeratic inner fan facies (Unit 1) Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). NG006511 Nushagak Bay Sedimentary 3151 Jmm2 Middle and Upper Jurassic turbidites of Metervik Bay, well-bedded outer (or mid?) fan lobe facies (Unit 2) Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). NG006512 Nushagak Bay Sedimentary 3151 Jmm3 Middle and Upper Jurassic turbidites of Metervik Bay, massive mid fan channel facies (Unit 3) Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). NG006513 Nushagak Bay Sedimentary 3151 Jmm4a Middle and Upper Jurassic turbidites of Metervik Bay, conglomeratic inner fan facies (Unit 4a, channel margin)Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). NG006514 Nushagak Bay Sedimentary 3151 Jmm4b Middle and Upper Jurassic turbidites of Metervik Bay, conglomeratic inner fan facies (Unit 4b, channel) Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). NG006515 Nushagak Bay Sedimentary 3151 Jmm4c Middle and Upper Jurassic turbidites of Metervik Bay, conglomeratic inner fan facies (Unit 4c, channel margin)Late and Middle Jurassic Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and Mutti, 1973): (from bottom to top) a conglomeratic inner fan facies unit; a weRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). NG006516 Nushagak Bay Sedimentary 3151 Jmm Middle and Upper Jurassic turbidites of Metervik Bay Late and Middle Jurassic Unit added by extension of polygon from Box (1985). Description from Box: Coherently deformed volcaniclastic turbidites southeast of Right Hand Fault. Reconstructed 6 km section, divided into four turbidite facies units (using criteria of Walker and MuRare fossils range from Bajocian (base of third unit) to Oxfordian (in upper unit). GO0063151 Goodnews Bay Sedimentary 3151 Jmt Middle Jurassic volcaniclastic turbidites of Togiak Bay Middle Jurassic Tightly folded volcaniclastic turbidites at least 1.7 km thick. Sandstones and conglomerates composed entirely of volcanic and hypabyssal igneous clasts. A few tool marks and interbedded slump folds suggest ENE-directed paleocurrents. Middle Jurassic ageMiddle Jurassic age constrained by occurrence of Bajocian pelecypods northeast of map area in Togiak River valley (Hoare and Coonrad, 1978a). Intruded by Aeolus Mtn. gabbro body with 174 +/- 8 m.y. K-Ar amphibole age. GO005512 Goodnews Bay Sedimentary 3152 Jmt Middle Jurassic volcaniclastic turbidites of Togiak Bay Middle Jurassic Tightly folded volcaniclastic turbidites at least 1.7 km thick. Sandstones and conglomerates composed entirely of volcanic and hypabyssal igneous clasts. A few tool marks and interbedded slump folds suggest ENE-directed paleocurrents. Middle Jurassic ageMiddle Jurassic age constrained by occurrence of Bajocian pelecypods northeast of map area in Togiak River valley (Hoare and Coonrad, 1978a). Intruded by Aeolus Mtn. gabbro body with 174 +/- 8 m.y. K-Ar amphibole age. HG003512 Hagemeister IslandSedimentary 3152 Jln Lower Jurassic? dismembered volcaniclastic turbidites Early Jurassic (?) Pervasively deformed and dismembered tuffaceous sandstone-shale sequence, predominately argillaceous. Sedimentary structures variably preserved and indicate deposition from turbidity currents and other mass flow processes. Original thickness uncertain. SPoorly preserved radiolaria from SF1 have been identified as post-Triassic Mesozoic forms. Clasts of slate similar to SF2 occur stratigraphically below Bajocian fossil occurrence in adjacent Middle Jurassic turbidites (Jmm). Deposition and deformation of GO005518 Goodnews Bay Sedimentary 3230 Jln Lower Jurassic? dismembered volcaniclastic turbidites Early Jurassic (?) Pervasively deformed and dismembered tuffaceous sandstone-shale sequence, predominately argillaceous. Sedimentary structures variably preserved and indicate deposition from turbidity currents and other mass flow processes. Original thickness uncertain. SPoorly preserved radiolaria from SF1 have been identified as post-Triassic Mesozoic forms. Clasts of slate similar to SF2 occur stratigraphically below Bajocian fossil occurrence in adjacent Middle Jurassic turbidites (Jmm). Deposition and deformation of HG003518 Hagemeister IslandSedimentary 3230 Jln Lower Jurassic? dismembered volcaniclastic turbidites Early Jurassic (?) Pervasively deformed and dismembered tuffaceous sandstone-shale sequence, predominately argillaceous. Sedimentary structures variably preserved and indicate deposition from turbidity currents and other mass flow processes. Original thickness uncertain. SPoorly preserved radiolaria from SF1 have been identified as post-Triassic Mesozoic forms. Clasts of slate similar to SF2 occur stratigraphically below Bajocian fossil occurrence in adjacent Middle Jurassic turbidites (Jmm). Deposition and deformation of NG006518 Nushagak Bay Sedimentary 3230 Jk Graywacke of Kulukak Bay, subdivided Middle to early Late Jurassic Subdivsion of unit into Box's (1985) volcaniclastic turbidites. A thick marine sedimentary unit referred to as "Weary graywacke" by Hoare and others, 1975. Consists of very hard graywacke and siltstone with local conglomerate. Buchia, Inoceramus, belemnites, and rare ammonite fragments ranging from Middle to early Late Jurassic age. GO0066130 Goodnews Bay Sedimentary 3230 Jlvs Volcanic and sedimentary rocks Early Jurassic Marine unit of mafic flows, some pillow structure, volcanic breccias, and massive fine- to medium-grained volcanogenic sedimentary rocks. Fractures commonly coated with laumontite Weyla pelecypods of Early Jurassic age. HG002132 Hagemeister IslandSedimentary 3254 HFS Jlv Lower Jurassic interbedded volcanic and sedimentary rocks Early Jurassic Basaltic to dacitic volcanic and volcaniclastic rocks. Volcanic rocks (locally pillowed) typically plagioclase +/- clinopyroxene +/- hornblende porphyries. Interbedded with pyroclastic and epiclastic rocks derived from similar volcanic rocks. Grades fromUpper unit of abundantly fossiliferous, well bedded sandstones and shales HG003516 Hagemeister IslandIgneous 3254 TJvb Upper Triassic-Lower Jurassic coarse volcaniclastic rocks Early Jurassic-Late Triassic Dense green tuffs, tuff breccias, pillow breccias, minor pillow basalt, and associated epiclastic rocks. Breccia clasts are aphanitic or plagioclase-clinopyroxene porphyries, often vesicular, mostly angular. Interbedded hyaloclastites and crystal tuffs. GO005522 Goodnews Bay Igneous 3255 TrJvb Upper Triassic-Lower Jurassic coarse volcaniclastic rocks Early Jurassic-Late Triassic Dense green tuffs, tuff breccias, pillow breccias, minor pillow basalt, and associated epiclastic rocks. Breccia clasts are aphanitic or plagioclase-clinopyroxene porphyries, often vesicular, mostly angular. Interbedded hyaloclastites and crystal tuffs. HG003522 Hagemeister IslandIgneous 3255 TrJvb Upper Triassic-Lower Jurassic coarse volcaniclastic rocks Early Jurassic-Late Triassic Unit as described by Box (1985), shown as hornfels and unit Jlvs by Hoare and Coonrad (1978). Dense green tuffs, tuff breccias, pillow breccias, minor pillow basalt, and associated epiclastic rocks. Breccia clasts are aphanitic or plagioclase-clinopyrox HG0021522 Hagemeister IslandIgneous 3255 HFS KJvs Volcanic and sedimentary rocks Early Cretaceous to Middle Jurassic Thick marine unit consisting of volcanic and sedimentary rocks. Volcanic rocks range in composition from mafic pillow basalts to more abundant andesitic and trachytic flows, tuffs, and breccias. Interbedded with the volcanic rocks are tuffaceous siltstRadiolaria of Late Jurassic to Early Cretaceous age, and fragmentary ammonites of Jurassic age. GO0066127 Goodnews Bay Sedimentary 3255 JTrp Togiak Terrane; Phyllite and chert Early Jurassic and Late Triassic (?) Gray, green, and black phyllite, fine-grained tuff, and tuffaceous chert. Single radiolarian collection of Early Jurassic (?) age BH0023260 Bethel Metamorphic 3260 Jct Jurassic laminated tuffs and associated rocks Jurassic Mixed unit characterized by banded to finely laminated crystal lithic tuffs with interbedded green, white, and black tuffaceous cherts. Minor interbedded sections of massive, coarse-grained lithic tuff and (or) pillow basalt (Jpb). Highly deformed, oftenSeveral cherts have yielded radiolaria of Jurassic age, one of which is identified as Tithonian (latest Jurassic). GO005520 Goodnews Bay Igneous 3310 Jct (Jpb)Jurassic laminated tuffs and associated rocks Jurassic Mixed unit characterized by banded to finely laminated crystal lithic tuffs with interbedded green, white, and black tuffaceous cherts. Minor interbedded sections of massive, coarse-grained lithic tuff and (or) pillow basalt (Jpb). Highly deformed, oftenSeveral cherts have yielded radiolaria of Jurassic age, one of which is identified as Tithonian (latest Jurassic). HG003520 Hagemeister IslandIgneous 3310 Jpb Jurassic laminated tuffs and associated rocks Jurassic Pillow basalt. Highly deformed, often with slaty or spaced cleavage, which is also folded. Partially altered to prennite-pumpellyite facies mineral assemblage. Several cherts have yielded radiolaria of Jurassic age, one of which is identified as TithoniaSeveral cherts have yielded radiolaria of Jurassic age, one of which is identified as Tithonian (latest Jurassic). GO005521 Goodnews Bay Igneous 3310 KJvs Volcanic and sedimentary rocks, subdivided Early Cretaceous to Middle Jurassic Thick marine unit consisting of volcanic and sedimentary rocks. Volcanic rocks range in composition from mafic pillow basalts to more abundant andesitic and trachytic flows, tuffs, and breccias. Interbedded with the volcanic rocks are tuffaceous siltstRadiolaria of Late Jurassic to Early Cretaceous age, and fragmentary ammonites of Jurassic age. GO0066128 Goodnews Bay Sedimentary 3310 Jt Trondhjemite Jurassic and Jurassic (?) Light-gray, medium-grained intrusive trondhjemite consisting of abundant quartz, plagioclase, and minor chlorite. GO002169 Goodnews Bay Igneous 3380 Jg Gabbroic rocks Jurassic and Jurassic (?) Medium- to coarse-grained, locally pegmatitic intrusive gabbroic rocks consisting of hornblende, clinopyroxene, and calcic plagioclase K/Ar age range of 159.3 to 186.9 m.y. from hornblende GO002167 Goodnews Bay Igneous 3406 Jg Gabbroic rocks Jurassic and Jurassic (?) Medium- to coarse-grained, locally pegmatitic intrusive gabbroic rocks consisting of hornblende, clinopyroxene, and calcic plagioclase K/Ar age range of 159.3 to 186.9 m.y. from hornblende HG002167 Hagemeister IslandIgneous 3406 Jmg Middle Jurassic gabbroic plutons Middle Jurassic Medium- to coarse-grained (locally pegmatitic) hornblende gabbro to diorite bodies, slightly altered (i.e., sericitized plagioclase, hornblende partially replaced by actinolite and chlorite, prehnite-quartz veinlets). Intrusive into a variety of units wi K-Ar amphibole ages range from 186 to 159 (minimum) m.y., or Middle Jurassic. GO005546 Goodnews Bay Igneous 3406 Jmg Middle Jurassic gabbroic plutons Middle Jurassic Medium- to coarse-grained (locally pegmatitic) hornblende gabbro to diorite bodies, slightly altered (i.e., sericitized plagioclase, hornblende partially replaced by actinolite and chlorite, prehnite-quartz veinlets). Intrusive into a variety of units wi K-Ar amphibole ages range from 186 to 159 (minimum) m.y., or Middle Jurassic. HG003546 Hagemeister IslandIgneous 3406 Jvs Volcanic and sedimentary rocks Middle to early Late Jurassic Volcanic and sedimentary rocks consisting of andesitic, trachytic, and basaltic flows and breccias with interbedded fine- to coarse-grained sedimentary rocks Fossils in related rocks, north of map area, are assigned a Middle Jurassic age. BH003131 Bethel Sedimentary 3450 Jab Andesitic and Basaltic lava flows and marine epiclastic rocks, Nyac terrane Middle Jurassic Andesitic and basaltic lava flows, flow breccias, and tuffaceous marine sedimentary rocks Marine pelecypods of Bajocian age (Middle Jurassic) BH0023450 Bethel Sedimentary 3450 Kkv Kuskokwim Group, volcanic rocks Jurassic Massive andesitic and basaltic flows; minor amounts of trachyte, trachyandesite, and dacite; some interbedded tuffaceous sedimentary rocks; and locally several hundred feet of volcanic breccia at or near base. These rocks from a belt of low rolling hillOriginally called Cretaceous on map; note revised to Jurassic and removed from Kuskokwim. BH00432261Bethel Igneous 3450 Kkv Kuskokwim Group, volcanic breccia Jurassic Several hundred feet of volcanic breccia at or near base of massive andesitic and basaltic flows; minor amounts of trachyte, trachyandesite, and dacite; some interbedded tuffaceous sedimentary rocks. These rocks from a belt of low rolling hills on the wOriginally called Cretaceous on map; note revised to Jurassic and removes from Kuskokwim. BH00432261Bethel Igneous 3450 Jmv Middle Jurassic interbedded volcanic and sedimentary rocks Middle Jurassic Basaltic and andesitic volcanic and volcaniclastic rocks, extensively altered to prehnite-pumpellyite facies assemblage. Volcanic rocks more common in lower third of exposed section, characterized by plagioclase + clinopyroxene +/- hornblende porphyries.Locally fossiliferous with Middle Jurassic fauna. GO005514 Goodnews Bay Sedimentary 3451 Jmv Middle Jurassic interbedded volcanic and sedimentary rocks Middle Jurassic Basaltic and andesitic volcanic and volcaniclastic rocks, extensively altered to prehnite-pumpellyite facies assemblage. Volcanic rocks more common in lower third of exposed section, characterized by plagioclase + clinopyroxene +/- hornblende porphyries.Locally fossiliferous with Middle Jurassic fauna. HG003514 Hagemeister IslandSedimentary 3451 Jum Ultramafic rocks Jurassic and Jurassic (?) Serpentinite, serpentinized dunite and websterite ultramafic rocks. K/Ar age range of 176.4 to 186.9 m.y. from hornblende GO002168 Goodnews Bay Igneous 3495 Jum Ultramafic rocks Jurassic and Jurassic (?) Serpentinite, serpentinized dunite and websterite ultramafic rocks. K/Ar age range of 176.4 to 186.9 m.y. from hornblende HG002168 Hagemeister IslandIgneous 3495 Jmu Middle Jurassic ultramafic plutons Middle Jurassic Occur only at Red and Susie Mtns. at west end of map area. Medium-grained dunite, wehrlite, and clinopyroxenite, partially (less than 25 percent) replaced by serpentine minerals. Around margins cut by numerous coarsely pegmatitic hornblendite dikes. Nort Hornblendite dikes yield Middle Jurassic K-Ar amphibole ages. GO005548 Goodnews Bay Igneous 3495 Jmu Middle Jurassic ultramafic plutons Middle Jurassic Occur only at Red and Susie Mtns. at west end of map area. Medium-grained dunite, wehrlite, and clinopyroxenite, partially (less than 25 percent) replaced by serpentine minerals. Around margins cut by numerous coarsely pegmatitic hornblendite dikes. Nort Hornblendite dikes yield Middle Jurassic K-Ar amphibole ages. HG003548 Hagemeister IslandIgneous 3495 TKg Granitic rocks Tertiary and Cretaceous Fine-, medium-, and coarse-grained, light- to dark-gray, rarely pink plutonic granitic rocks. Chiefly quartz monzonite, granodiorite, and quartz diorite K/Ar age range of 62.5 to 72.5 m.y. from biotite and hornblende HG002165 Hagemeister IslandIgneous 3510 Jmf Middle Jurassic granodiorite pluton Middle Jurassic Medium-grained biotite-hornblende granodiorite of Hagemeister Island; slightly altered (i.e. sericitized plagioclase, chlorite partially replacing biotite and hornblende). Intrusive into Lower Jurassic rocks (Jlv) with narrow contact metamorphic zone of Yielded K-Ar hornblende age of 183 +/- 7 m.y. HG003544 Hagemeister IslandIgneous 3510 Pzmg Metagabbro and greenstone Paleozoic (?) Massive, fine- to coarse-grained, locally pegmatitic, greenish metagabbro and greenstone. Probable dismembered altered ophiolite complex consisting of mafic flows, dikes, volcaniclastic rocks, and gabbro. HG002147 Hagemeister IslandMetamorphic 3890 Trub Upper Triassic (?) pillow basalts Upper Triassic Pillow basalts, aphanitic to porphyritic, with interbedded pillow breccia, hyaloclastite, and interpillow and interbedded red and white radiolarian chert. Porphyries consist of plagioclase + clinopyroxene phenocrysts with intergranular to subophitic grouConsidered Upper Triassic based on radiolarian ages of associated bedded chert. GO005524 Goodnews Bay Igneous 3891 Trub Upper Triassic (?) pillow basalts Upper Triassic Pillow basalts, aphanitic to porphyritic, with interbedded pillow breccia, hyaloclastite, and interpillow and interbedded red and white radiolarian chert. Porphyries consist of plagioclase + clinopyroxene phenocrysts with intergranular to subophitic grouConsidered Upper Triassic based on radiolarian ages of associated bedded chert. HG003524 Hagemeister IslandIgneous 3891 Jt Trondhjemite Jurassic and Jurassic (?) Light-gray, medium-grained intrusive trondhjemite consisting of abundant quartz, plagioclase, and minor chlorite. HG002169 Hagemeister IslandIgneous 3892 Trut Upper Triassic (?) trondhjemite Late Triassic(?) Altered and irregularly cataclastized trondhjemitic plutonic rocks composed of plagioclase and quartz with minor seams of chlorite, sericite, and clinozoisite (lawsonite locally: Hoare and Coonrad, 1978b). Shown on map only south of Security Cove but sma HG003554 Hagemeister IslandIgneous 3892 Trud Upper Triassic (?) diabasic intrusive rocks Late Triassic(?) Subophitic, holocrystalline plagioclase-clinopyroxene diabase (grain size to 1.5 mm). Occurs as 0.3 to 1.0-m-wide sills and dikes with basalt and chert screens west of Matogak River mouth, as thick sills intruding chert at Pyrite Point, as dikes cutting K-Ar amphibole age of hornfels is 187 +/- 10 m.y. HG003550 Hagemeister IslandIgneous 3893 Trud Upper Triassic (?) diabasic intrusive rocks Late Triassic(?) Originally mapped as MzPz by Hoare abd Coonrad (1978), unit is shown as described by Box (1985) with hornfels of Hoare and Coonrad (1978) added. Subophitic, holocrystalline plagioclase-clinopyroxene diabase (grain size to 1.5 mm). Occurs as 0.3 to 1.0-m K-Ar amphibole age of hornfels is 187 +/- 10 m.y. HG0021550 Hagemeister IslandIgneous 3893 HFS Trug Upper Triassic (?) pyroxene gabbro Late Triassic(?) Altered clinopyroxene gabbro, locally up to 5 percent orthopyroxene. Augitic pyroxene (diallage) often kinked and fractured, occasionally rimmed or replaced by pale-green actinolitic amphibole. Plagioclase partially to completely replaced by fine aggrega HG003552 Hagemeister IslandIgneous 3894 su Serpentinized ultramafic rocks Thoroughly serpentinized ultramafic rocks. Protoliths were predominately harzburgite (5-25 percent bastite pseudomorphs after orthopyroxene) with subordinate dunite and rare clinopyroxenite. Locally near Cape Newenham preserves a lineated tectonite fabri GO005556 Goodnews Bay Metamorphic 3895 su Serpentinized ultramafic rocks Thoroughly serpentinized ultramafic rocks. Protoliths were predominately harzburgite (5-25 percent bastite pseudomorphs after orthopyroxene) with subordinate dunite and rare clinopyroxenite. Locally near Cape Newenham preserves a lineated tectonite fabri HG003556 Hagemeister IslandMetamorphic 3895 Pzcs Calcareous schist Paleozoic Schistose calcareous siltstone, limestone, and greenish tuffaceous rocks. GO002150 Goodnews Bay Metamorphic 3950 Pzcs Calcareous schist Paleozoic Schistose calcareous siltstone, limestone, and greenish tuffaceous rocks. HG002150 Hagemeister IslandMetamorphic 3950 JTrmc Upper Triassic-Lower Jurassic calcareous schists Early Jurassic-Late Triassic Partially to completely recrystallized calcareous phyllites and schists. Protoliths include calcareous sandstones and shales, limestone conglomerates, limestone, volcanic conglomerates and mafic volcanic rocks. Clastics locally preserve turbidite feature GO005540 Goodnews Bay Metamorphic 3950 JTrmc Upper Triassic-Lower Jurassic calcareous schists Early Jurassic-Late Triassic Partially to completely recrystallized calcareous phyllites and schists. Protoliths include calcareous sandstones and shales, limestone conglomerates, limestone, volcanic conglomerates and mafic volcanic rocks. Clastics locally preserve turbidite feature HG003540 Hagemeister IslandMetamorphic 3950 JTrmb Upper Triassic-Lower Jurassic (?) metabasaltic schists Early Jurassic (?)-Late Triassic Partially to completely recrystallized schistose rocks with mafic igneous protoliths, including pillow basalts, angular volcanic breccia, pebbly mudstone, fine tuffaceous sedimentary rocks, diabase, gabbro, and rare chert. Greenschist to transitional gre Two mica separates yield Late Jurassic K-Ar ages, probably resulting from Late Jurassic thermal event. GO005536 Goodnews Bay Metamorphic 3990 JTrmb Upper Triassic-Lower Jurassic (?) metabasaltic schists Early Jurassic (?)-Late Triassic Partially to completely recrystallized schistose rocks with mafic igneous protoliths, including pillow basalts, angular volcanic breccia, pebbly mudstone, fine tuffaceous sedimentary rocks, diabase, gabbro, and rare chert. Greenschist to transitional gre Two mica separates yield Late Jurassic K-Ar ages, probably resulting from Late Jurassic thermal event. HG003536 Hagemeister IslandMetamorphic 3990 JTrmb Upper Triassic-Lower Jurassic (?) metabasaltic schists Early Jurassic (?)-Late Triassic Originally shown as part of unit KJvs by Hoare and Coonrad (1978), unit shown as described by Box (1985) with hornfels from Hoare and Coonrad (1978) added. Partially to completely recrystallized schistose rocks with mafic igneous protoliths, including p Two mica separates yield Late Jurassic K-Ar ages, probably resulting from Late Jurassic thermal event. HG0021536 Hagemeister IslandMetamorphic 3990 HFS JPvss Permian-Jurassic (?) volcaniclastic sandstone and conglomerate Jurassic (?)-Permian Unit distinguished only near Goodnews Bay. Characterized by round cobble conglomerate, entirely composed of plagioclase phyric volcanic clasts, alternating with turbiditic sandstone-shale sequences. Distribution suggests it unconformably overlies Permian Middle Jurassic K-Ar amphibole ages GO005532 Goodnews Bay Sedimentary 3991 JPvss Permian-Jurassic (?) volcaniclastic sandstone and conglomerate Jurassic (?)-Permian Unit distinguished only near Goodnews Bay. Characterized by round cobble conglomerate, entirely composed of plagioclase phyric volcanic clasts, alternating with turbiditic sandstone-shale sequences. Distribution suggests it unconformably overlies Permian Middle Jurassic K-Ar amphibole ages HG003532 Hagemeister IslandSedimentary 3991 JTrmvss Upper Triassic-Lower Jurassic volcaniclastic schists Early Jurassic (?)-Late Triassic Partially recrystallized schistose rocks with sandstone, shale, and conglomerate protoliths derived from feldspar-rich volcanic source. Rounded conglomerate clasts mostly plagioclase +/- pyroxene +/- hornblende amygdaloidal porphyritic volcanic rocks, bu Single K-Ar determination yields a Late Triassic amphibole age. GO005538 Goodnews Bay Metamorphic 3991 JTrmvss Upper Triassic-Lower Jurassic volcaniclastic schists Early Jurassic (?)-Late Triassic Partially recrystallized schistose rocks with sandstone, shale, and conglomerate protoliths derived from feldspar-rich volcanic source. Rounded conglomerate clasts mostly plagioclase +/- pyroxene +/- hornblende amygdaloidal porphyritic volcanic rocks, bu Single K-Ar determination yields a Late Triassic amphibole age. HG003538 Hagemeister IslandMetamorphic 3991 Trvs Volcanic and sedimentary rocks Triassic Marine unit consisting of chert, tuffaceous cherty rocks, argillite, siltstone, volcanic wacke, conglomerate, limestone, and mafic flows and breccias. Pelecypods of Late Triassic age GO002135 Goodnews Bay Sedimentary 4035 Trvs Volcanic and sedimentary rocks Triassic Marine unit consisting of chert, tuffaceous cherty rocks, argillite, siltstone, volcanic wacke, conglomerate, limestone, and mafic flows and breccias. Pelecypods of Late Triassic age BH003135 Bethel Sedimentary 4035 Trb Togiak Terrane; Pillow basalt and minor interbedded chert Late Triassic Massive pillow basalt and basaltic breccia interbedded with thin-bedded tuffaceous chert and shale BH0024215 Bethel Igneous 4215 MzPz Mesozoic and Paleozoic rocks, undivided Early Cretaceous to Early(?) Ordovician Thick, widespread, marine unit consisting of volcanic and sedimentary rocks ranging in age from Early (?) Ordovician to Early Cretaceous. Unit consists of thin-bedded to massive tuffaceous cherts and siltstones, argillite, graywacke, pebble-cobble conglLimestones commonly contain Permian fossils GO002145 Goodnews Bay Sedimentary 4710 MzPz Mesozoic and Paleozoic rocks, undivided Early Cretaceous to Early(?) Ordovician Thick, widespread, marine unit consisting of volcanic and sedimentary rocks ranging in age from Early (?) Ordovician to Early Cretaceous. Unit consists of thin-bedded to massive tuffaceous cherts and siltstones, argillite, graywacke, pebble-cobble conglLimestones commonly contain Permian fossils HG002145 Hagemeister IslandSedimentary 4710 KCg Gemuk Group Early Cretaceous to Mississippian(?) Chiefly massive and thin-bedded, fine-grained siliceous rocks, some volcanic rocks, calcareous siltstone, and limestone. In the Bethel quadrangle, most probably of Jurassic, Triassic, and Permian age. BH00434710Bethel Sedimentary 4710 TJik Little Kasigluk River pluton Early Tertiary (?), Cretaceous, and Jurassic Small masses (less than 6 km (square)) of medium-grained, hypidiomorphic granular hornblende diorite and gabbro BH0023405 Bethel Igneous 4880 MzPz Mesozoic and Paleozoic rocks, undivided Early Cretaceous to Early(?) Ordovician Thick, widespread, marine unit consisting of volcanic and sedimentary rocks ranging in age from Early (?) Ordovician to Early Cretaceous. Unit consists of thin-bedded to massive tuffaceous cherts and siltstones, argillite, graywacke, pebble-cobble conglLimestones commonly contain Permian fossils GO002146 Goodnews Bay Sedimentary 4950 TrPzm Tikchik Terrane; Melange Triassic and Paleozoic Structurally complex assemblage of intercalated chert, limestone, basalt, and greywacke Fossils recovered from limestone are Permian and Late Triassic age. Radiolarian fossils from chert are Paleozoic (?), pre-Late Devonian, Devonian (?), and Triassic ages. BH0025091 Bethel Sedimentary 4950 KCgc Gemuk Group, chert, siltstone, graywacke and limestone Mississippian(?) Massive and thin-bedded chert interbedded with siltstone and graywacke (generally calcareous), thin-bedded limestone and minor amount of mafic volcanic rocks, all of Mississippian(?) age. Chert is black, white and gray. No green chert, which is charact BH00434713Bethel Tectonite 4950 MzPzc Chert and argillite, Goodnews terrane Mesozoic and (or) Paleozoic White, gray-green, and blue-green recrystallized chert in 2- to 5-cm thick beds interbedded with black to dark-green phyllite or slate beds of similar thickness Recrystallized radiolarians (Phanerozoic) BH0025026 Bethel Metamorphic 5026 MzPzv Goodnews Terrane; Volcaniclastic sandstone and argillite Mesozoic and (or) Paleozoic Turbiditic, thin-bedded, medium- to fine-grained, volcaniclastic sandstone and dark-green to black argillite having weak to nonexistant slaty cleavage BH0025045 Bethel Sedimentary 5045 MzPzs Arkosic sandstone and slate, Goodnews terrane Mesozoic and (or) Paleozoic Strongly cleaved, medium-grained, generally thin-bedded, arkosic sandstone and slate BH0025050 Bethel Sedimentary 5050 TrDs Tikchik Terrane; Marine sandstone, shale, limestone, and conglomerate Middle (?) Triassic to Late Devonian Well-bedded, cleaved sandstone, shale, thin limestone interbeds, and cobble conglomerate Conodont collection of Middle (?) Triassic and Late Devonian to Early Mississippian ages BH0025060 Bethel Sedimentary 5060 MzPza Goodnews Terrane; Argillaceous melange with blocks of limestone, basalt, and chert Mesozoic and (or) Paleozoic Argillaceous melange of black to green, weakly to intensely fracture foliated argillite with discontinuous phacoids of recrystallized radiolarian chert and limey sandstone Permian pelecypods and Permian conodonts BH0025090 Bethel Sedimentary 5090 MzPza Goodnews Terrane; Argillaceous melange with blocks of limestone, basalt, and chert Mesozoic and (or) Paleozoic Show by extension from Box and others, 1993. Argillaceous melange of black to green, weakly to intensely fracture foliated argillite with discontinuous phacoids of recrystallized radiolarian chert and limey sandstone Permian pelecypods and Permian conodonts GO0065090 Goodnews Bay Sedimentary 5090 MzPzp Goodnews Terrane; Chloritic Phyllite Mesozoic and (or) Paleozoic Relatively homogeneous unit of finely foliated and crenulated phyllite BH0025217 Bethel Metamorphic 5217 MzPzm Goodnews Terrane; Metachert and Phyllitic Metachert Mesozoic and (or) Paleozoic Finely crystalline, thin-bedded quartzites (metachert) and finely interlayered quartzite and black phyllite Recrystallized radiolarians (Phanerozoic) BH0025225 Bethel Metamorphic 5225 MzPzb Metabasalt and minor metachert, Goodnews terrane Mesozoic and (or) Paleozoic Weakly to strongly foliated metabasalt having variable recrystallization to greenschist-facies assemblage of albite-epidote-chlorite-actinolite. Interbedded sequences of thin-bedded, white to green metachert having white mica-rich laminae. Mid-ocean ri Metamorphic cooling constrained to Late Jurassic or Early Cretaceous time based on K/Ar age of 146.0+15.0 Ma from actinolite BH0025240 Bethel Metamorphic 5239 DOs Schist and metachert Devonian(?) to Ordovician(?) Massively bedded green amphibole and chlorite schist interbedded with metachert; overlain by crystalline limestone, phyllite, and minor amounts of chlorite, graphite, and quartz-sericite schists. BH00435240Bethel Metamorphic 5239 Pl Limestone Permian Thin, widespread, fine-grained, crystalline limestone. Fetid odor. Generally tuffaceous, locally cherty. GO002140 Goodnews Bay Sedimentary 5730 Pl Limestone Permian Thin, widespread, fine-grained, crystalline limestone. Fetid odor. Generally tuffaceous, locally cherty. HG002140 Hagemeister IslandSedimentary 5730 Pl Limestone Permian Thin, widespread, fine-grained, crystalline limestone. Fetid odor. Generally tuffaceous, locally cherty. BH004140 Bethel Sedimentary 5730 Pl Permian limestone Permian Massive recrystallized gray limestone with fetid odor of H2S upon breaking. Weak fracture cleavage masks bedding. Occurs as large blocks along low-angle fault between schistose rocks to northwest and mafic igneous rocks southeast of Kinegnak River. Age gAge given by shell fragments of Atomodesma sp. GO005528 Goodnews Bay Sedimentary 5730 Pl Permian limestone Permian Massive recrystallized gray limestone with fetid odor of H2S upon breaking. Weak fracture cleavage masks bedding. Occurs as large blocks along low-angle fault between schistose rocks to northwest and mafic igneous rocks southeast of Kinegnak River. Age gAge given by shell fragments of Atomodesma sp. HG003528 Hagemeister IslandSedimentary 5730 KCgl Limestone and calcareous siltstone and sandstone Permian Massive and thin-bedded, partly recrystallized, cream-colored limestone, estimated 500 to 1,000 feet thick near Chaekuktuli Lake; near Chikuminuk Lake, consists of interbedded gray silty limestone and calcareous siltstone and sandstone. Invertebrate fossils reported by Mertie (1938) BH00435730Bethel Sedimentary 5730 KCgl Gemuk Group, limestone and calcareous siltstone and sandstone Permian Conprises a belt of calcareous rocks of Permian age stratigraphically underneath but grading upward into the volcanic sequence. Near Lake Chaekuktuli, the rocks are massive and thin-bedded, partly recrystalized, cream-colored limestone, estimated to be BH00434712Bethel Sedimentary 5730 Pvs Permian volcaniclastic rocks Permian Volcaniclastic sedimentary rocks, ranging from coarsely bedded volcanic breccias to finely bedded calcareous tuffaceous rocks. Limestone cobble conglomerate locally north of Goodnews Bay. Red to black laminated argillite with radiolarian ghosts locally nRed to black laminated argillite with radiolarian ghosts locally north and east of Goodnews Bay. Age constrained by several occurrences of fragmentary Atomodesma sp. GO005526 Goodnews Bay Sedimentary 5746 Pvs Permian volcaniclastic rocks Permian Volcaniclastic sedimentary rocks, ranging from coarsely bedded volcanic breccias to finely bedded calcareous tuffaceous rocks. Limestone cobble conglomerate locally north of Goodnews Bay. Red to black laminated argillite with radiolarian ghosts locally nRed to black laminated argillite with radiolarian ghosts locally north and east of Goodnews Bay. Age constrained by several occurrences of fragmentary Atomodesma sp. Prehnite-pumpellyite facies. GO006626 Goodnews Bay Sedimentary 5746 Pv Volcanic rocks Permian Unit consists of basalt flows, breccias, and a few sandy tuffs. Basalts are mostly amygdaloidal and mildly altered. Unit includes columnar-jointed flows and pillow basalts interbedded with pillow breccias. Volcanic rocks grade downward into fossilifer GO002137 Goodnews Bay Igneous 5810 Pb Permian (?) pillow basalt Permian (?) Pillow basalts, associated breccias and diabasic intrusive. Interbedded with Pvs unit. Prehnite pumpellyite facies. GO005530 Goodnews Bay Igneous 5810 Pb Permian (?) pillow basalt Permian (?) Pillow basalts, associated breccias and diabasic intrusive. Interbedded with Pvs unit. Prehnite pumpellyite facies. Revision of Hoare and Coonrad (1978) based on Box (1985). Also, volcanic rocks separated from unit MzPz of Hare and Coonrad (1978). Tha GO006630 Goodnews Bay Igneous 5810 KCgv Gemuk Group, volcanic rocks Triassic(?) and Permian Predominantly altered dark-green to almost black mafic volcanic rocks of Permian age having abundant amygdules. Volcanic breccia, calcareous tuff, and pillow lava make up basal part of section. Pillow lavas also occur elsewhere in section. Thin-beddedFossils of Permian age in limestone southeast of quardangle below unit and of questionable Triassic age in the Eek Mountains to south of quadrangle BH00435810Bethel Igneous 5810 KCgv Gemuk Group, volcanic rocks Permian(?) Predominantly altered mafic volcanic rocks of Permian age; dark-green to almost black with abundant amygdules, few identifiable phenocrysts. Volcanic breccia, calcareous tuffs, and pillow lava constitute basal beds. Lavas with well-formed pillow struc BH00434711Bethel Sedimentary 5810 MDv Tikchik Terrane; Massive volcanic and volcaniclastic rocks Early Mississippian and (or) Late Devonian Weakly to moderately foliated and flattened pillowed and massive basalt, andesite, dacite, and rhyolite flows and breccia with greenschist-facies metamorphic-mineral assemblages Mississippian fossils BH0026412 Bethel Igneous 6412 MDm Marble and metabasaltic dikes, Goodnews terrane Early Mississippian and (or) Late Devonian Light-gray to white calcitic and dolomitic marble cut by premetamorphic basaltic dikes. Rare metamorphic blue amphiboles (magnesioriebeckite) in metabasalt dikes indicate relatively high pressure, low temperature metamorphism Age constrained by conodonts of latest Devonian to earliest Mississippian age BH0026380 Bethel Metamorphic 6580 DOs Schist and metachert -- limestone Devonian(?) to Ordovician(?) Limestone mapped speparately in massively bedded green amphibole and chlorite schist interbedded with metachert; overlain by crystalline limestone, phyllite, and minor amounts of chlorite, graphite, and quartz-sericite schists. BH00435240Bethel Metamorphic 6580 DOl Limestone Devonian to Ordovician Thin-bedded to massive, fine-grained, highly fractured limestone. Local interbedded tuffs and mafic volcanic rocks. Locally recrystallized to marble. Sparse fossils of Early to Middle Devonian age and Early (?) Ordovician age. GO002142 Goodnews Bay Sedimentary 6995 Dl Devonian limestone Devonian Poorly exposed white limestone at southwest end of larger belt of fossiliferous Devonian shallow marine limestone (Hoare and Coonrad, 1978a). fossiliferous Devonian shallow marine limestone. GO005534 Goodnews Bay Sedimentary 6995 DOl Limestone Devonian to Ordovician Thin-bedded to massive, fine-grained, highly fractured limestone. Local interbedded tuffs and mafic volcanic rocks. Locally recrystallized to marble. Sparse fossils of Early to Middle Devonian age and Early (?) Ordovician age. GO0066995 Goodnews Bay Sedimentary 6995 pCl Marbleized limestone Precambrian White, gray, and brownish, locally garnetiferous marbleized limestones GO002155 Goodnews Bay Metamorphic 8610 pCk Metamorphic rocks of Kanektok River region Precambrian Gneiss and schist in the Kanektok River region. Sedimentary, volcanic, and plutonic rocks metamorphosed in the upper greenschist and lower amphibolite facies. Consists of medium- to coarse-grained, massive, and well-foliated biotite-hornblende gneisses K/Ar ages as old as 2,000 m.y. from biotite and hornblende GO002152 Goodnews Bay Metamorphic 9420 Xo Amphibolite-facies orthogneiss and amphibolite with minor intercalated pelititc schist, Kilbuck terrane Early Proterozoic Strongly lineated and foliated, muscovite, biotite-muscovite, or amphibole orthogneiss with granite to tonalite to diorite protoliths. More extensively exposed in Goodnews Bay quadrangle, where it also includes amphibolite and minor pelitic schist Two U/Pb age of igneous protolith of 2.06 Ga from zircon. Nd/Sm isotopic systematics indicate that the rocks formed at 2 Ga. Amphibolite-facies metamorphism U-Pb age of 1.78 Ga from sphene. Cretaceous overprinting of most K/Ar ages suggest thermal/dynBH0029420 Bethel Metamorphic 9420 pCm Metamorphic complex preCambrian Coarse-grained pink gneiss and medium- to coarse-grained light- to dark-gray schist constituting a sequence of highly sedimentary, volcanic, possibly some intrusive rocks BH00439420Bethel Metamorphic 9420