rock unit,unit name,age,description,fossil,radiometric age,source,class,quadrangle,rock class,nsaclass,label, nsamod,qclass "btu","Bedrock unknown","Unknown but likely Precambrian or older","type unknown; relations uncertain","","","OP002","9001","Ophir","","99","pCu","","" "bu pc /TrMc","None","Uncertain","Map shows questionable identification of unit.","","","OP002","902","Ophir","Metamorphic","99","bu","","" "Qac","Alluvium","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits. Chiefly silt and very fine sand. Terrace deposits largely fluival but in part lacustrine; slope deposits primarily eolian and colluvial. ","The ""Palisades"" along the Yukon have yielded Pleistocene vertebrate fauna including mammoth and bison remains. ","","MZ002","100","Melozitna","Unconsolidated","100","Qal","","" "Qu","None","Quaternary","Undifferientiated lowland silt, sand, muck, and gravel","","","OP002","102","Ophir","Unconsolidated","100","Qs","","" "Qf","Floodplain deposits","Quaternary","Floodplain deposits","","","KT002","100","Kateel River","Unconsolidated","100","Qs","","" "Qac","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","Quaternary","Chiefly silt and very fine sand. Includes extensive loess deposits","","","MD002","105","Medfra","Unconsolidated","100","Qs","","" "Qcal","Colluvium and alluvium, undifferentiated","Quaternary","Silt and sand mantling broad, flat valleys","","","TN002","100","Tanana","Unconsolidated","100","Qs","","" "Qu","Alluvium","Quaternary","Silt, sand, and gravel of stream beds, flood plains, and terraces ","","","RB003","100","Ruby","Unconsolidated","100","Qs","","" "Q","Surficial materials, undivided","Quaternary","Includes stream alluvium, colluvial deposits, terrace gravel, eolian deposits, and glacial deposits","","","TN003","100","Tanana","Unconsolidated","100","Qs","","" "Qc","Fluvial, colluvial, and eolian terrace and slope deposits, undivided","Holocene and Pleistocene","Silt and very fine sand","","","UL002","109","Unalakleet","Unconsolidated","100","","","" "Qu","Unconsolidated deposits","Quaternary","Silt, sand, and gravel of stream beds, flood plains, and terraces ","","","RB004","100","Ruby","Unconsolidated","100","Qs","","" "Q","Surficial deposits","Quaternary","Alluvium, colluvium, and loess","","","RB002","100","Ruby","Unconsolidated","100","Qs","","" "Q","Surficial deposits","Quaternary","Undifferentiated glacial drift, eolian and alluvial deposits","","","BT002","100","Bettles","Unconsolidated","100","Qs","","" "Qae","Undifferentiated alluvium, eolian terrace and slope deposits","Pleistocene and Recent","Undifferentiated alluvium and eolian terrace and slope deposits of silt and very fine sand","","","HU002","115","Hughes","Unconsolidated","100","Qs","","" "Qae","Undifferentiated alluvial and eolian deposits","Quaternary","Undifferentiated alluvial and eolian deposits, chiefly silt and fine sand. Includes glacial outwash and fan gravels locally.","","","SH002","11","Shungnak","Unconsolidated","100","Qs","","" "Qua","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.","","","SP003","706","Survey Pass","Unconsolidated","100","","","" "Qua","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","","","BT003","100","Bettles","Unconsolidated","100","Qs","","" "Qua","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.","","","AR003","703","Ambler River","Unconsolidated","100","Qs","","" "Qua","Alluvial, colluvial, glacial, and windblown deposits, undivided","Quaternary","Glacial deposits, alluvuim, colluvium, and landslides.","","","WI003","113","Wiseman","Unconsolidated","100","Qs","","" "Qua","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","Quaternary","Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits","","","WI003","113","Wiseman","Sedimentary","100","","","" "Qua","Alluvium","Quaternary","Undifferentiated alluvial, colluvial and eolian terrace and slope deposits","","","RB009","811","Ruby","Unconsolidated","100","Qua","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels","","","SE004","400","Selawik","Unconsolidated","100","","","1000" "Qc","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels","","","UL003","200","Unalakleet","Unconsolidated","100","","","1000" "Q","Surficial deposits","Quaternary","Undifferentiated glacial drift, eolian and alluvial deposits","","","wi004","100","Wiseman","Unconsolidated","100","Qs","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels. ","","","OP005","102","Ophir ","Unconsolidated","100","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels. ","","","OP005","910","Ophir ","Unconsolidated","100","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels.","","","HU003","100","Hughes","Unconsolidated","100","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels.","","","MD004","105","Medfra","Unconsolidated","100","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels.","","","TN008","30100","Tanana","Unconsolidated","100","","","" "Q","Surficial deposits","Quaternary","Alluvium, colluvium, and loess","","","RB005","100","Ruby","Unconsolidated","100","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels","","","NL004","500","Nulato","Unconsolidated","100","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Quaternary, Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravel","","","KT004","901","Kateel River","Unconsolidated","100","Qs","","" "Qal","Alluvium","Quaternary","Silt, sand, and gravel of stream beds, flood plains, and terraces ","","","RB002","101","Ruby","Unconsolidated","105","Qa","","" "Qfy","Younger flood-plain deposits","Quaternary","Light-gray micaceous silt. Sand and gravel along streams that drain bendrock uplands. Characterized physiographically by badrs, oxbows, meander scars, abandoned channels, and other evidence of recent flood-plain building. ","","","MZ002","110","Melozitna","Unconsolidated","105","Qac","","" "Qal","Alluvium","Quaternary","Silt, sand and gravel of streambeds, flood plains and terraces","","","NL002","101","Nulato","Unconsolidated","105","Qa","","" "Qa","None","Quaternary","Alluvium","","","OP002","101","Ophir","Unconsolidated","105","Qal","","" "Qfy","Younger flood-plain deposits","Quaternary","Light-gray micaceous silt. Sand and gravel along streams that drain bedrock uplands","","","KT002","102","Kateel River","Unconsolidated","105","Qac","","" "Qal","Recent alluvium","Holocene","Sandy gravel and sandy silt, forms flood plain of modern rivers and streams.","","","TN002","105","Tanana","Unconsolidated","105","Qal","","" "Qags","Older alluvium","Quaternary","Coarse, silty sand and fine gravel; generally forms terrace sloping up and away from floodplains of streams and rivers","","","TN002","111","Tanana","Unconsolidated","105","Qa","","" "Qfy","Younger flood-plain deposits","Quaternary","Chiefly light-gray micaeous silt along Yukon and Koyukuk rivers. Silt, sand and gravel along streams that drain bedrock uplands. Locally include some terrace and fan deposits along narrow tributary valleys. Mapped from aerial photographs.","","","NL003","100","Nulato","Unconsolidated","105","","","" "Qf","Flood-plain deposits","Holocene","Silt, sand, and gravel along floodplains of stream valleys","","","UL002","110","Unalakleet","Unconsolidated","105","","","" "Qf","Flood-plain deposits","Quaternary","Flood-plain deposits. Gravel, sand, and silt along flood-plains of major stream valleys","","","CA002","100","Candle","Unconsolidated","105","Qa","","" "Qfp","Flood Plain deposits","Pleistocene and recent","Flood Plain deposits of gravel, sand, and silt along flood plains of major drainages","","","HU002","110","Hughes","Unconsolidated","105","","","" "Qfp","Flood-plain deposits","Quaternary","Silt, sand, and gravel along flood plains of major drainages. Locally includes some fan and terrace deposits along narrow tributary valleys","","","SH002","1","Shungnak","Unconsolidated","105","Qa","","" "Qft","Flood-plain deposits","Quaternary","Silt, sand, and gravel along flood plains of major drainages. Locally includes some fan and terrace deposits along narrow tributary valleys","","","SE002","105","Selawik","Unconsolidated","105","Qa","","" "Qa","Alluvial deposits","Quaternary","Unconsolidated gravel, sand, silt, and clay","","","BM002","102","Baird Mountains","Unconsolidated","105","Qa","","" "Qf","Floodplain and tidal flats deposits.","Quaternary","Floodplain and tidal flats deposits. Gravel, sand, silt, and peat","","","SP003","702","Survey Pass","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits","Quaternary","Floodplain and tidal flats deposits. Gravel, sand, silt, and peat.","","","BT003","109","Bettles","Unconsolidated","105","Qa","","" "Qf","Floodplain and tidal flat deposits.","Quaternary","Floodplain and tidal flat deposits. Gravel, sand, silt, and peat.","","","AR003","701","Ambler River","Unconsolidated","105","Qa","","" "Qf","Floodplain and tidal flat deposits.","Quaternary","Floodplain and tidal flat deposits. Gravel, sand, silt, and peat.","","","BM003","1000","Baird Mountains","Unconsolidated","105","Qa","","" "Qf","Floodplain and tidal flats deposits","Quaternary","Floodplain and tidal flats deposits. Gravel, sand, silt, and peat","","","WI003","110","Wiseman","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits","Quaternary","Floodplain and tidal flats deposits","","","RB009","810","Ruby","Unconsolidated","105","Qf","","" "Qf","Flood Plain deposits","Pleistocene and recent","Flood Plain deposits of gravel, sand, and silt along flood plains of major drainages","","","HU003","217","Hughes","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt. ","","","OP005","101","Ophir","Unconsolidated","105","","","" "Qf ","Floodplain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","KT004","902","Kateel River ","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","MD004","700","Medfra","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","MZ004","730","Melozitna","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","TN008","30105","Tanana","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","KT004","4102","Kateel River ","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","KT004","300","Kateel River ","Unconsolidated","105","","","" "Qf","Floodplain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt","","","NL004","105","Nulato","Unconsolidated","105","","","" "Qaf","Alluvial fan deposits","Quaternary","Gravel, silt, and sand, commonly occur at mouth of small side canyons. Includes some colluvial deposits.","","","TN002","106","Tanana","Unconsolidated","106","Qaf","","" "Qc","None","Quaternary","Colluvium","","","OP002","104","Ophir","Unconsolidated","107","Qc","","" "Qc","Colluvium, undifferentiated","Quaternary","Predominantly silt, with some sand and gravel.","","","TN002","107","Tanana","Unconsolidated","107","Qc","","" "Qta","Talus","Quaternary","Angular boulder rubble in cirque.","","","TN002","159","Tanana","Unconsolidated","107","Qc","","1071" "Qh","High-level eolian and colluvial deposits","Pleistocene","Windblown and reworked windblown deposits of silt and very fine sand","","","UL002","111","Unalakleet","Unconsolidated","107","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels. ","","","OP005","104","Ophir ","Unconsolidated","107","","","" "Qrs","Recent slide and slump deposits","Holocene","Very fresh, unmodified slumps and earthflows (Occurred about 1940).","","","TN002","158","Tanana","Unconsolidated","108","Qls","","" "Qls","Older landslide deposits","Quaternary","Slumps and earth and rock slides","","","TN002","108","Tanana","Unconsolidated","108","Qls","","" "ls","Landslide deposits","Quaternary?","Not described","","","NL004","108","Nulato","Unconsolidated","108","","","" "Qt","None","Quaternary","Terrace alluvium","","","OP002","103","Ophir","Unconsolidated","110","Qt","","" "Qt","Terrace deposits","Quaternary","Terrace deposits","","","KT002","101","Kateel River","Unconsolidated","110","Qt","","" "Qhs","High terrace and slope deposits","Quaternary","Light-gray and grayish-orange micaceous silt. Subordinate lenses of sand and peat.","","","KT002","104","Kateel River","Unconsolidated","110","Qt","","" "Qbg","Low-level bench gravel of Minook Creek","Quaternary","Gravel and sand on bench along lower parts of Minook and Hunter Creeks","","","TN002","109","Tanana","Unconsolidated","110","Qt","","" "Qtr","Terrace deposits","Quaternary","Gravel, silt, and sand near mouth of Fleshlanana Creek","","","TN002","110","Tanana","Unconsolidated","110","Qt","","" "Qhs","High-terraces and slope deposits","Quaternary","Light-gray and grayish-orange micaeous silt deposits. Subordinate lenses of sand and peat. Deposits form a broad terrace 10 to 100 m above the floodplain of the Koyukuk Flats and extend as much as 250 m up the slopes of the bedrocks hills surrounding the Flats. Terrace deposits characterized by thermokarst topography marked by many small lakes. Unit also forms terrace and slope deposits along streams that drain bedrock uplands and locally include coarse-grained colluvial and fan deposits.","","","NL003","110","Nulato","Unconsolidated","110","","","" "Qt","Terrace deposits","Quaternary","Terraced alluvial silt deposits with minor peat and gravel","","","CA002","150","Candle","Unconsolidated","110","Qt","","" "Qt","Terrace and slope deposits","Holocene and Pleistocene","Terrace and slope deposits","","","NR002","68","Norton Bay","Unconsolidated","110","Qt","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels","","","SE004","401","Selawik","Unconsolidated","110","","","1100" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided ","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels. ","","","CA003","3150","Candle","Unconsolidated","110","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels.","","","KT004","104","Kateel River ","Unconsolidated","110","","","" "Qua","Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided","Holocene and Pleistocene","Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands. Local deposits of alluvial fan and glacial outwash gravels","","","NL004","410","Nulato","Unconsolidated","110","","","" "Qfo","Older flood-plain deposits","Quaternary","Chiefly light-gray and grayish-orange micaeous silt. Locally include peat, reworked eolian sand and gravel. Deposits at or near river level but youthful flood-plain features are much modified or absent. Contact with Qfy locally gradational and poorly defined.","","","MZ002","130","Melozitna","Unconsolidated","111","Qac","","" "Qfo","Older floodplain deposits","Quaternary","Chiefly light-gray and grayish-orange micaceous silt. Locally includes peat, reworked eolian sand, and gravel","","","KT002","103","Kateel River","Unconsolidated","111","Qac","","" "Qfy","Younger flood-plain deposits","Quaternary","Silt, sand, and gravel","","","MD002","101","Medfra","Unconsolidated","111","Qac","","" "Qfo","Older flood-plain deposits","Quaternary","Largely silt and sand but probably includes abundant gravel along Tonzona River.","","","MD002","102","Medfra","Unconsolidated","111","Qac","","" "Qfo","Older flood-plain deposits","Quaternary","Cheifly light-gray and grayish-orange micaeous silt. Subordinate lenses of sand and peat, reworked eolian sand, and gravel. Deposits are at or near river level but youthful floodplain features such as oxbow lakes, meander scrolls, and abandoned channels are much modified or absent.","","","NL003","111","Nulato","Unconsolidated","111","","","" "Qf","Floodplain and tidal flats deposits ","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.","","","MD004","101","Medfra","Unconsolidated","111","","","" "Qf","Flood-plain and estuarine deposits","Holocene","Flood-plain and estuarine deposits","","","NR002","24","Norton Bay","Unconsolidated","116","Qes","","" "Qf","Flood-plain and tidal flats deposits","Holocene","Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt","","","NR003","9","Norton Bay","Unconsolidated","116","Qes","","" "Qna","Nogahabara sand dunes -- active dunes","Quaternary","Active dunes. Circular body, nearly 5 mi in diameter. Entriely sand, free of vegetation cover.","","","KT002","110","Kateel River","Unconsolidated","119","Qd","","1190" "Qs","Sand","Quaternary","Eolian sand deposits of the Kobuk Sand Dunes","","","BM002","104","Baird Mountains","Unconsolidated","119","Qd","","1190" "Qsa","Actively drifting and recently stabilized dune fields ","Holocene","Fine- to coarse-grained sand","","","KT004","900","Kateel River ","Unconsolidated","119","","","1190" "Qsa","Actively drifting and recently stabilized dune fields","Holocene","Great Kobuk and Little Kobuk Sand Dunes in the southwestern Ambler River and southeastern Baird Mountains quadrangles, and Nogahabara Sand Dunes in the Kateel River quadrangle. The Great Kobuk and Little Kobuk dune fields covering 24 square miles (65 square kilometers) and 3 square miles (8 square kilometers), respectively, are composed of parabolic or U-shaped dunes and large transverse dune ridges that locally develop into barchan-like dunes. Wind direction varies from NE to SE. Fine- to coarse-grained sand","","","AR003","715","Ambler river","Unconsolidated","119","","","1190" "Qms","Modified eolian sand deposits","Quaternary","Dark-yellowish-orange and light-gray, fine- to medium-grained eolian sand. Forms briad sheetlike dune field mantling older floodplain (Qfo) and alluvial terrace (Qac) deposits of the Dulbi Flats. Deposits have a strong northeast-southwest trend.","","","MZ002","120","Melozitna","Unconsolidated","120","Qd","","" "Qns","Nogahabara sand dunes -- stabilized dunes","Quaternary","Scattered circular and elliptical bodies of eolian sand.","","","KT002","111","Kateel River","Unconsolidated","120","Qd","","" "Qms","Modified eolian sand deposits","Quaternary","Dark-yellowish-orange and light-gray, fine- to medium-grained eolian sand. Forms broad sheet-like dune field mantling alluvial silt deposits of the Koyukuk flats and all but tops of bedrock hills in vicinity of Roundabout Mountain.","","","KT002","112","Kateel River","Unconsolidated","120","Qd","","" "Qms","Modified eolian sand deposits","Quaternary","Sheetlike dune fields of tan fine- to medium-grained eolian sand, locally overlain by peat and loess","","","MD002","103","Medfra","Unconsolidated","120","Qd","","" "Qess","Sand and silt","Quaternary","Well-sorted sand, commonly in subdued dune forms","","","TN002","120","Tanana","Unconsolidated","120","Qd","","" "Qs","Chiefly sand deposits","Quaternary","Modified and dissected deposits of wind-blown and water-laid sand with subordinate amounts of silt","","","SH002","9","Shungnak","Unconsolidated","120","Qd","","" "Qs","Chiefly sand deposits","Quaternary","Modified and dissected deposits of wind-blown and water-laid sand with subordinate amounts of silt","","","SE002","120","Selawik","Unconsolidated","120","Qd","","" "Qws","Chiefly wind-blown and water-laid silt","Quaternary","Chiefly wind-blown and water-laid silt. Locally includes glacial outwash.","","","SE002","110","Selawik","Unconsolidated","120","Qd","","" "Qs","Eolian deposits","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","SP003","711","Survey Pass","Unconsolidated","120","","","" "Qs","Eolian and water-laid sand sheets and sand dunes.","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","BT003","112","Bettles","Unconsolidated","120","Qd","","" "Qs","Eolian and water-laid sand sheets and dunes.","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","AR003","700","Ambler River","Unconsolidated","120","Qd","","" "Qs","Eolian and water-laid sand sheets and dunes.","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","BM003","1104","Baird Mountains","Unconsolidated","120","Qd","","" "Qs","Eolian and water-laid sand sheets and dunes.","Quaternary","Eolian and water-laid sand sheets and active and stabilized sand dunes.","","","WI003","112","Wiseman","Sedimentary","120","","","" "Qs","Eolian and water-laid sand and silt","Quaternary","Eolian and water-laid sand and silt","","","RB009","812","Ruby","Unconsolidated","120","Qs","","" "Qs","Chiefly sand deposits","Quaternary","Modified and dissected deposits of wind-blown and water-laid sand with subordinate amounts of silt","","","SE004","402","Selawik","Unconsolidated","120","Qd","","" "Qs","Eolian and water-laid sand and silt sheets and stabilized dune fields","Holocene and Pleistocene","Modified and partly dissected sheets of mixed wind-blown and water-laid deposits bordering the south edge of the Brooks Range","","","SH004","709","Shungnak","Unconsolidated","120","","","" "Qs","Eolian and water-laid sand and silt sheets and stabilized dune fields ","Holocene and Pleistocene","Sand and coarse silt. ","","","HU003","120","Hughes ","Unconsolidated","120","","","" "Qs","Eolian and water-laid sand and silt sheets and stabilized dune fields ","Holocene and Pleistocene","Sand and coarse silt.","","","KT004","112","Kateel River ","Unconsolidated","120","","","" "Qs","Eolian and water-laid sand and silt sheets and stabilized dune fields ","Holocene and Pleistocene","Sand and coarse silt. ","","","SH004","709","Shungnak","Unconsolidated","120","","","" "Ql","Loess","Quaternary","Well-sorted silt","","","TN002","121","Tanana","Unconsolidated","121","Qfl","","" "Qg","Glacial drift","Quaternary","Unsorted bouldery till and isolated moraines; may include some younger solifluction deposits near valley sides.","","","MZ002","140","Melozitna","Unconsolidated","125","Qm","","" "Qg","Glacial drift","Quaternary","Unsorted bouldery till","","","MD002","104","Medfra","Unconsolidated","125","Qm","","" "Qdw","Glacial drfit","Quaternary, probable Wisconsin","Chiefly till and outwash deposits of Walker Lake Glaciation","","","SH002","3","Shungnak","Unconsolidated","125","Qm","","" "Qda","Glacial drfit","Quaternary, probable Wisconsin","Chiefly till and outwash deposits of Ambler Glaciation. Locally includes outwash of Walker Lake Glaciation.","","","SH002","5","Shungnak","Unconsolidated","125","Qm","","" "Qg","Glacial deposits","Quaternary","Undifferentiated glacial deposits.","","","BM002","103","Baird Mountains","Unconsolidated","125","Qm","","" "Qm","Glacial deposits","Quaternary","Locally mapped glacial deposits","","","TN007","9001","Tanana","Unconsolidated","125","Qm","","" "QTgl","Glacial and glaciolacustrine deposits.","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits. Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.","","","SP003","703","Survey Pass","Unconsolidated","125","","","" "QTgl","Glacial and glaciolacustrine deposits.","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits. Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.","","","AR003","702","Ambler River","Unconsolidated","125","Qm","","" "QTgl","Glacial and glaciolacustrine deposits.","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits. Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.","","","BM003","1103","Baird Mountains","Unconsolidated","125","Qm","","" "QTgl","Glacial and glaciolacustrine deposits","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits. Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits.","","","WI003","111","Wiseman","Sedimentary","125","","","" "QTgl","Glacial and glaciolacustrine deposits ","Pleistocene and Pliocene?","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits. Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits. Further south, in the Bettles, Hughes, Shungnak. and Selawik quadrangles, the unit is composed of discontinuous areas of highly modified drift of Pliocene? and early Pleistocene age interspersed with alluvium and eolian deposits. Glacial erratics occur in hilly parts of the central Shungnak and Hughes quadrangles to an elevation of 1,500 feet (600 meters). In the Bettles quadrangle the southern margin of the unit consists chiefly of lacustrine sediments deposited from a large proglacial lake.","","","HU003","125","Hughes ","Unconsolidated","125","","","" "QTgl","Glacial and glaciolacustrine deposits ","Pleistocene and Pliocene?","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits. Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits. Further south, in the Bettles, Hughes, Shungnak. and Selawik quadrangles, the unit is composed of discontinuous areas of highly modified drift of Pliocene? and early Pleistocene age interspersed with alluvium and eolian deposits. Glacial erratics occur in hilly parts of the central Shungnak and Hughes quadrangles to an elevation of 1,500 feet (600 meters). In the Bettles quadrangle the southern margin of the unit consists chiefly of lacustrine sediments deposited from a large proglacial lake.","","","TN008","30125","Tanana","Unconsolidated","125","","","" "Qt4","Till, Cirque glaciation","Quaternary?","Unsorted boulder to clay-size particles. Moraine forms locally present, restricted to cirques","","","TN002","130","Tanana","Unconsolidated","130","Qnd","","" "Qt","Till, undifferentiated","Quaternary","Unsorted boulder to clay-size particles, no clear morainic forms.","","","TN002","135","Tanana","Unconsolidated","135","Qwu","","" "Qyg","Younger Glacial drift","Pleistocene and recent","Younger Glacial drift of till and outwash gravel and sand","","","HU002","125","Hughes","Unconsolidated","135","","","" "Qt3","Till","Quaternary","Unsorted boulder to clay-size particles, includes long low lateral moraine on Halu Creek","","","TN002","136","Tanana","Unconsolidated","136","Qwr","","" "Qt2","Till","Quaternary","Unsorted boulder to clay-size particles, lowest moraine on Halu Creek","","","TN002","137","Tanana","Unconsolidated","137","Qw2","","" "Qt1","Till","Quaternary?","Unsorted boulder to clay-size particles, farthest down valley moraine on lower Halu Creek.","","","TN002","138","Tanana","Unconsolidated","138","Qw1","","" "Qb","Rock-defended terraces on Minook Creek","Quaternary","Erosional benches along east side Minook Creek","","","TN002","160","Tanana","Unconsolidated","160","Qrd","","" "Qat","Altiplanation terrace","Quaternary","Flat, even surface, formed on bedrock hilltops generally above 600 m","","","TN002","161","Tanana","Unconsolidated","161","Qat","","" "Qga","Undifferentiated older glacial drift and alluvium","Pleistocene and recent","Undifferentiated older glacial drift and alluvium of glacial till and outwash, silt, colluvium, and loess","","","HU002","120","Hughes","Unconsolidated","190","","","" "Qga","Undifferentiated older glacial drfit, alluvium, and eolian deposits","Quaternary, Illinoian","Chiefly highly modified till and outwash gravels mantled by wind-blown and water-laid silt and fine sand.","","","SH002","7","Shungnak","Unconsolidated","190","Qog","","" "Qga","Undifferentiated older glacial drfit, alluvium, and eolian deposits","Quaternary, Illinoian","Chiefly highly modified till and outwash gravels mantled by wind-blown and water-laid silt and fine sand.","","","SE002","190","Selawik","Unconsolidated","190","Qog","","" "QTgl","Glacial and glaciolacustrine deposits","Quaternary","Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits. Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges (shown by hachured lines), ice-contact features, and glaciolacustrine deposits. In the Bettles quadrangle the southern margin of the unit consists chiefly of lacustrine sediments deposited from a large proglacial lake.","","","BT003","111","Bettles","Unconsolidated","190","Qog","","" "QTg","Gravel deposits on Jones Creek","Quaternary-Tertiary","Moderately dipping gravel exposed on Jones Creek near Nixon Fork fault, approximately 25 m thick","","","MD002","151","Medfra","Unconsolidated","285","QTg","","" "QTg","High-level gravel","late Tertiary or early Quaternary","Well packed gravel, caps hills in vicinity of Rampart","","","TN002","285","Tanana","Unconsolidated","285","QTg","","" "QTgr","Quartz gravel deposits","Quaternary/Tertiary","High-level deposits of quartz pebble gravel; overlies basalt flows of unit Tb.","","","BT003","127","Bettles","Unconsolidated","285","QTg","","" "QTgr ","Quartz gravel deposits","Quaternary or Tertiary","High-level deposits of quartz pebble gravel; overlies basalt flows of unit Tb. ","","","TN008","30285","Tanana","Unconsolidated","285","","","" "Qya","Younger alkalic basalt cones and flows","Pleistocene","More than 40 alkali basalt, basanite, and hawaiite cones, short flows, and maar craters","","","UL002","112","Unalakleet","Igneous","300","","","" "Qyt","Younger tholeiitic basalt cones and flows","Holocene (?) and Pleistocene","Black glassy olivine tholeiite basalt flows of well-preserved pahoehoe structure including ropy flow surfaces and lava tubes","","Whole-rock K/Ar age of 0.19+0.02 Ma","UL002","113","Unalakleet","Igneous","305","","","" "QTb","Basalt","early Quaternary or late Tertiary","Nearly horizontal flows of vesicular olivine basalt. Flows extruded over terrain of moderate relief, ranging in elevation from 175 to over 1,600 feet.","","","KT002","500","Kateel River","Igneous","350","QTb","","" "QTb","Older basalt flows","Pleistocene and Pliocene","Abundant vesicular tholeiitic and alkali olivine baslt flows which form a broad shield volcano. Columnar jointed. Tholeiitic basalt has diktytaxitic texture","","4 whole-rock K/Ar ages of 3.25+0.11 Ma, 2.8+0.1 Ma, 1.99+0.06 Ma, and 1.39+0.04 Ma.","UL002","108","Unalakleet","Igneous","350","","","" "QTb","Basalt","Tertiary (?) and Quaternary","Flows of vesicular olivine basalt. Minor glassy basalt. Believed to be correlative with Imuruk Volcanics of Bendeleben quad","","","CA002","500","Candle","Igneous","350","QTb","","" "QTb","Basalt","Pleistocene or Late Tertiary","Dissected, nearly horizontal flows of gray to dark-red vesicular olivine basalt.","","","SH002","23","Shungnak","Igneous","350","QTb","","" "QTb","Basalt","Pleistocene or Late Tertiary","Dissected, nearly horizontal flows of gray to dark-red vesicular olivine basalt.","","","SE002","500","Selawik","Igneous","350","QTb","","" "QTb","Basalt","Pleistocene or Pliocene","Basalt","","","NR002","76","Norton Bay","Igneous","350","QTb","","" "QTb","Basalt flows ","Pleistocene and Pliocene","Vesicular tholeiitic and alkali basalt flows. In Candle and Selawik quadrangles unit includes several alkali basalt cones and flows that contain abundant peridotite inclusions. ","","K/Ar isotopic cooling ages from the volcanic field in western part of Unalakleet quadrangle range from 3.25 Ma to 1.39 Ma.","CA003","500","Candle","Igneous","350","","","" "QTa","Andesitic lava","Late Tertiary or early Quaternary","Light to very light-gray vesicular lava. Removed from final map","","","TN002","451","Tanana","Igneous","451","QTa","","" "Ts","Sandstone, Claystone, Conglomerate, and Lignite","Tertiary","Grayish-white granule conglomerate and sandstone, reddish-brown claystone, and lignite coal. Exposed at river level at the ""Palisades"" along the Yukon River.","Pollen of probable Miocene age.","","MZ002","200","Melozitna","Sedimentary","640","Tcb","","" "Ts","Sedimentary rocks","early Tertiary and Miocene","Interbedded polymictic pebble-cobble-boulder conglomerate, grit, and sandstone, with siltstone, shale, and lignite.","","","TN002","640","Tanana","Sedimentary","640","Tcb","","" "Ts","Sedimentary rocks, undivided","Tertiary, Eocene","Interbedded polymictic pebble-cobble-boulder conglomerate, grit, and sandstone, with siltstone, shale, and lignite.","","","TN003","640","Tanana","Sedimentary","640","Tcb","","" "Ts","Clay shale and coal","Miocene or Oligocene","Poorly consolidated deposits of gray to brown clay shale, lignitic coal, and yellow volcanic ash","Pollen and spore assemblages from lignite (Seldovian age)","","UL002","123","Unalakleet","Sedimentary","640","","","" "Ts","Shale, sandstone, and coal","Miocene? or Oligocene?","Shale, sandstone, and coal","","","NR002","396","Norton Bay","Sedimentary","640","Tcb","","" "Ts","Gravel and sand","Tertiary","A small cutbank exposure of moderately dipping gravel and sand at north edge of Selawik Hills on eastern tributary of Mangoak River. Composed chiefly of poorly sorted granitic rock detritus that appears to have been derived from nearby granitic rocks","","","SE002","1320","Selawik","Sedimentary","640","","","" "Ts","Small deposits of nonmarine conglomerate, sandstone, shale, and coal ","Tertiary","Poorly consolidated nonmarine deposits. In the Melozitna and Tanana quadrangles consist of sandstone, claystone, conglomerate, and lignite exposed on south bank of Yukon River near the border of the Melozitna and Tanana quadrangles and small outcrops on the north side of the Yukon River in the Tanana quadrangle located close to the Kaltag Fault. Elsewhere in the Tanana quadrangle consist of sandstone, shale, coal, and lignite exposed on the Tozitna River and its tributaries in central part of Tanana quadrangle.","Pollen samples from these five areas range in age from Oligocene to Pliocene. ","","TN008","30640","Tanana","Unconsolidated","640","","","" "none","Fault zone rocks","Tertiary or older","Rocks within major fault zones; may be cataclastic or mylonitic, variable ages depending on fault and country rocks","","","TN007","9002","Tanana","Unconsolidated","999","fg","","" "Tvs","Rhyolitic volcanic and sedimentary rocks","Tertiary?","Rhyolitic lava and breccia. Tuff and welded tuff common. Cherty rocks minor, thin-bedded or in nodules.","","","TN002","1001","Tanana","Igneous","1001","Trs","","" "Tv","Volcanic rocks, undivided","Paleocene to Eocene","Bimodal assemblage of rhyolite and banded rhyolite flow rocks, rhyolitic breccia, tuffaceous sedimentary rocks, and amygdaloidal basalt flow rocks.","","","TN003","1001","Tanana","Igneous","1001","Trs","","" "Tr","Rhyolite and dacite","Eocene","Composed of finely banded flows, tuffs, breccias, and hypabyssal domal intrusive bodies","","Two samples with K-Ar ages, one yielded 50.6 +/- 1.5 on biotite and 47.6 +/- 1.4 hornblende, the other 53.3 +/- 1.6 biotite and 49.1 +/- 1.5 hornblende","NL003","201","Nulato","Igneous","1002","","","" "Td","Rhyolite domes and flows","Eocene or Paleocene","Well exposed erosional remnants of rhyolite domes and flows and associated basal breccia and tuff","","K/Ar age of 56.0+1.7 Ma from sanidine","UL002","120","Unalakleet","Igneous","1002","","","" "Kv","Andesitic volcanic rocks","Early Cretaceous","Andesitic crystal-bearing lithic tuff and tuff breccia; probably correlative with andesitic volcanic rocks of Neocomian age in Hughes quad (Patton and Miller, 1966)","","","BT002","135","Bettles","Igneous","1002","Kve","","" "TKv","Volcanic rock","Tertiary","Indian River, and Dulbi River areas- light-gray to pink rhyolite tuff, welded (?) tuff, flows, and breccia. Subordinate pumice, dark vitrophyre, and obsidian. Reassigned to Tertiary by Patton (1998), separated from Takhakhdona Hills by Patton (2000)","Obsidian chippings and artifacts found in archeological site in NW AK may have source in obsidian occurrence north of Little Indian River.","Flows in Tanana and Bettles quads have K-Ar date of 58 m.y.","MZ004","210","Melozitna","Igneous","1002","Trs","","" "Td","Dacite and rhyolite lava flows, domes, and volcaniclastic rocks","Eocene and Paleocene","Finely banded dacitic and rhyolitic lava flows, basal breccia, tuffs, obsidian, and hypabyssal domal intrusive bodies. Spatially associated with andesite and basalt unit (Ta) and forms a compositionally continuous suite with unit Ta. ","","K/Ar isotopic cooling ages range from 60 to 40 Ma.","TN008","31002","Tanana","Igneous","1002","","","" "QTb","Basalt","Quaternary or Tertiary","Horizontal flows of dark vesicular to massive olivine basalt; subordinate volcanic conglomerate and breccia ","","","BT002","105","Bettles","Igneous","1004","QTb","","" "Tb","Basalt flows ","Oligocene","Vesicular and columnar-jointed basalt flows and lahar deposits. ","","Unit yielded a K/Ar cooling age of 32 Ma.","TN008","30350","Tanana","Igneous","1004","","","" "Thr","Hypabyssal rhyolite","Eocene or Paleocene","Fine-grained porphyritic hyabyssal rhyolite.","","","UL002","122","Unalakleet","Igneous","1011","","","" "TKv","Felsic volcanic rocks","Tertiary and Cretaceous (?)","Brown, gray, and light-tan porphyritic flows, breccia, conglomerate, and tuff of acidic and intermediate composition","","K/Ar age of 58 =?- 1.7 m.y.","BT002","110","Bettles","Sedimentary","1081","Tda","","" "Tad","Andesite and basalt lava flows and volcaniclastic rocks (Ta) and dacite and rhyolite lava flows, domes, and volcaniclastic rocks (Td), undivided ","Eocene and Paleocene","Confined to west-central part of Melozitna quadrangle where field data are insufficient to map units Ta and Td separately.","","","MZ004","4210","Melozitna","Igneous","1081","","","" "TKv","Volcanic rock","Tertiary to Late Cretaceous","Indian River, Takhakhdona Hills, and Dulbi River areas- light-gray to pink rhyolite tuff, welded (?) tuff, flows, and breccia. Subordinate pumice, dark vitrophyre, and obsidian. In Takhakhdona Hills also includes dark-green to black vesicular basalt flows. Big Creek- dark-green to green dacite and andesite porphyry flows and crystal tuffs. Probably correlative with similar flows and tuffs in Tanana and Bettles quads. Basalt and andesite flows reassigned to Tertiary by Patton (1998)","Obsidian chippings and artifacts found in archeological site in NW AK may have source in obsidian occurrence north of Little Indian River.","Flows in Tanana and Bettles quads have K-Ar date of 58 m.y.","MZ002","220","Melozitna","Igneous","1103","Tvab","","" "Ta","Andesite and basalt flows","Eocene and Paleocene","Columnar-jointed andesite and basalt flows. Andesite dominant, basalt much less common.","","","NL003","200","Nulato","Igneous","1103","","","" "Ta","Andesite and basalt flows","Eocene and Paleocene","1,500 m exposure of subaerial columnar-jointed andesite and basalt flows","","K/Ar age of 65.2+3.9 Ma from hornblende in the base of the unit. Whole-rock K/Ar age of 51.9+1.6 Ma from the top of the unit.","UL002","119","Unalakleet","Igneous","1103","","","" "KJv","Andesitic volcanic rocks - Roundabout Mountain volcanic field","Cretaceous and Jurassic(?)","Chiefly porphyritic pyroxene andesite and trachyandesite flows, andesitic crystal and lithic tuff, and massive andesite breccia, agglomerate, and conglomerate. Commonly altered and therefore pale green. Interbedded dark-greenish-gray tuffaceous graywacke, chert, shale, and impure limestone containing Buchia. Mildly deformed and unaltered vesicular basalt and associated pyroclastic rocks along Koyukuk River near Roundabout Mt. may be of Tertiary age.","","","KT004","801","Kateel River","Igneous","1103","Tvab","","" "Ta","Andesite and basalt","Eocene","Andesite and basalt","","","NR002","12","Norton Bay","Igneous","1103","Tvab","","" "TKv","Volcanic rock","Tertiary","In Takhakhdona Hills dark-green to black vesicular basalt flows.","","","MZ004","4220","Melozitna","Igneous","1103","Tvab","","" "Ta","Andesite and basalt flows","Eocene and Paleocene","1,500 m exposure of subaerial columnar-jointed andesite and basalt flows","","K/Ar age of 65.2+3.9 Ma from hornblende in the base of the unit. Whole-rock K/Ar age of 51.9+1.6 Ma from the top of the unit.","UL003","205","Unalakleet","Igneous","1103","","","" "Ta","Andesite and basalt lava flows and volcaniclastic rocks ","Eocene and Paleocene","Subaerial, columnar-jointed, andesite and basalt lava flows that locally contain interbedded tuffs, breccias, and agglomerates. Lava flows composed chiefly of pyroxene andesite and less commonly of hornblende-bearing high-silica andesite, olivine-bearing basaltic andesite, and basalt. Upper part of unit locally underlies and is intruded by dacite and rhyolite of unit Td. ","","K/Ar isotopic cooling ages range from 65 to 52 Ma. ","TN008","31103","Tanana","Igneous","1103","","","" "Ta","Andesite and basalt lava flows and volcaniclastic rocks","Eocene and Paleocene","Subaerial, columnar-jointed, andesite and basalt lava flows that locally contain interbedded tuffs, breccias, and agglomerates. Lava flows composed chiefly of pyroxene andesite and less commonly of hornblende-bearing high-silica andesite, olivine-bearing basaltic andesite, and basalt. Upper part of unit locally underlies and is intruded by dacite and rhyolite of unit Td","","K/Ar isotopic cooling ages range from 65 to 52 Ma","OP005","5201","Ophir","Igneous","1103","","","" "Tt","Tuff and tuff breccia","Eocene or Paleocene","1,000 m of (1) green intercaldera tuff and tuff breccia, (2) white rhyolite breccia, domes, and ash, (3) highly altered green andesite and dacite flows, and (4) minor pink granite dikes. 500 m of section consists of the green intercaldera tuff and tuff breccia","","","UL002","124","Unalakleet","Igneous","1120","","","" "Tg","Granite","early Tertiary","Light-gray biotite granite, only at Manley Hot Springs","","K-Ar(?) 62 Ma","TN002","2470","Tanana","Igneous","1320","Tpgr","","" "Tg","Granite","Eocene or Paleocene","Stock composed of pink to light-gray granite and quartz monzonite. Fine-grained hypidiomorphic granular or sparsely porphyritic granitic rocks characterized by plagioclase laths","","K/Ar age of 56.2+1.7 Ma from biotite","UL002","121","Unalakleet","Igneous","1320","","","" "TKs","Tuff, sandstone, conglomerate, and shale","Early Tertiary and Late Cretaceous","Nonmarine sedimentary rocks rich in volcanic components. In central part of quadrangle, unit consists of quartz-rich sandstone, conglomerate, siltstone, tuff, tuff breccia, and locally abundant carbonized plant debris. In southeast part of quadrangle, unit consists of quartz-chert-pebble conglomerate, sandstone, and siltstone containing abundant plant fossils and thin coaly layers","","","UL002","117","Unalakleet","Sedimentary","1510","","","" "TKe","Extrusive rocks","Cretaceous or Tertiary ","Basaltic, andesitic, and rhyolitic flows, tuffs, and breccias, and a few dacite flows; interbedded sandstone and shale. Flows commonly porphyritic and gently dipping. Probably greater than 500 feet thick.","","","RB002","202","Ruby","Igneous","1600","TKvr","","" "TKv","Volcanics","Early Tertiary and Late Cretaceous","Volcanics","","","OP002","201","Ophir","Igneous","1600","TKv","","" "TKv","Volcanic rocks of Nixon Fork-Upper Sulukna River area","Latest Cretaceous, earliest Tertiary","Sills, dikes, flows, and plugs of rhyolite, dacite, and trachyandesite.","","62-67 Ma","MD002","206","Medfra","Igneous","1600","TKnf","","" "TKv","Extrusive rocks","Cretaceous or Tertiary ","Basaltic, andesitic, and rhyolitic flows, tuffs, and breccias, and a few dacite flows; interbedded sandstone and shale. Flows commonly porphyritic and gently dipping. Probably greater than 500 feet thick. (Description from RB002, should match on this map.)","","","RB003","202","Ruby","Igneous","1600","TKvr","","" "TKu","Rhyolite, dacite, andesite, and basalt","Early Tertiary and Late Cretaceous","Volcanic and hypabyssal rocks of uncertain composition and age","","","UL002","118","Unalakleet","Igneous","1600","","","" "TKva","Basaltic andesite, basalt, and lapilli tuff","Tertiary(?) and Cretaceous","Medium-greenish-gray, aphanitic to fine-grained, porphyritic, hornblende-rich basaltic andesite; uncommon basalt and very fine grained lapilli tuff(?)","","","OP003","1600","Ophir","Igneous","1600","TKv","","" "TKad","Andesite and basalt lava flows and volcaniclastic rocks (TKa) and dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks (TKd), undivided","early Tertiary and Late Cretaceous","Andesite and basalt lava flows and volcaniclastic rocks (TKa) and dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks (TKd), undivided","","","UL003","202","Unalakleet","Igneous","1600","","","" "TKs","Tuff, sandstone, conglomerate, and shale","Early Tertiary and Late Cretaceous","Nonmarine sedimentary rocks rich in volcanic components. In central part of quadrangle, unit consists of quartz-rich sandstone, conglomerate, siltstone, tuff, tuff breccia, and locally abundant carbonized plant debris. In southeast part of quadrangle, unit consists of quartz-chert-pebble conglomerate, sandstone, and siltstone containing abundant plant fossils and thin coaly layers Unit lumped from proposed I-map (UL002) in overlying extrusive rocks.","","","UL003","3117","Unalakleet","Sedimentary","1600","","","" "TKu","Rhyolite, dacite, andesite, and basalt","Early Tertiary and Late Cretaceous","Dacite, rhyolite, and trachyandesite lava flows, domes, sills, dikes, and interlayered breccias and tuffs. Composed of phenocrysts of plagioclase, quartz, sanidine, and biotite in a groundmass of quartz and feldspar. Locally in Unalakleet and Medfra quadrangles, tuffs at the base of unit contain interbeds of quartz- chert-pebble conglomerate, sandstone, siltstone, and thin coaly layers with abundant plant fossils","Palynoflora collected from coaly layers at the base of the unit in the Medfra quadrangle are latest Cretaceous (Campanian or Maastrichtian) in age","K/Ar isotopic cooling ages for this unit range from 71 to 53 Ma","UL003","206","Unalakleet","Igneous","1600","","","" "TKv","Volcanic and sedimentary rocks","Tertiary? and or Cretaceous","Porphyritic basalt, andesite, and rhyolite flows, tuffs, and breccias with minor intercalated siltstone and sandstone. Unit widespread south of the Poorman Fault, volcanic rocks and tuff in Spruce Creek and Main Creek north of the fault probably correlative","","","RB005","120","Ruby","Igneous","1600","","","" "TKd","None","Early Tertiary and Late Cretaceous","Dikes and subvolcanic rocks","","","OP002","204","Ophir","Igneous","1601","TKd","","" "Khi","Hypabyssal intrusive rocks","Cretaceous","Small bodies of hypabyssal intrusive rocks including latite and quartz latite porphyry","","","HU002","195","Hughes","Igneous","1602","","","" "Khe","Felsic hypabyssal and extrusive rocks","Cretaceous(?)","Small widely scattered bodies of fine-grained intrusive and extrusive rocks including soda rhyolite, quartz latite porphyry, sanidine trachyte, and quartz diorite. Some welded tuff at eastern end of Selawik Hills.","","","SE002","2210","Selawik","Igneous","1602","TKvr","","" "TKi","Shallow intrusive rocks of silicic and intermediate composition","Tertiary and Cretaceous","Includes a wide variety of shallow intrusive rocks including rhyolite, dacite, trachyite, and andesite plugs, domes, sills, and dikes and larger more coarsely crystalline bodies of granite, granodiorite, tonalite, and monzonite porphyry","","","BT003","129","Bettles","Igneous","1602","TKgp","","" "TKi","Felsic hypabyssal and extrusive rocks","Cretaceous(?)","Small widely scattered bodies of fine-grained intrusive and extrusive rocks including soda rhyolite, quartz latite porphyry, sanidine trachyte, and quartz diorite. Some welded tuff at eastern end of Selawik Hills.","","","SE004","3010","Selawik","Igneous","1602","TKvr","","" "Khe","Felsic hypabyssal and extrusive rocks","Cretaceous(?)","Small widely scattered bodies of fine-grained intrusive and extrusive rocks including soda rhyolite, quartz latite porphyry, sanidine trachyte, and quartz diorite. Some welded tuff at eastern end of Selawik Hills.","","","SE004","3010","Selawik","Igneous","1602","TKvr","","" "TKnr","Volcanic rocks of the Nowitna River area -- rhyolite","Latest Cretaceous, earliest Tertiary","Altered rhyolite domes and associated rhyolitic tuff and breccia.","","","MD002","201","Medfra","Igneous","1603","TKnr","","" "TKs","Volcanic rocks of the Sischu Mountains","Latest Cretaceous, earliest Tertiary","Light-gray to purplish-red banded rhyolite and dacite subaerial flows and domes, locally containing interlayered breccia and tuff.","","66-71 Ma","MD002","207","Medfra","Igneous","1603","TKvs","","" "TKsc","Conglomerate, sandstone, and lignite","Latest Cretaceous, earliest Tertiary","Conglomerate, sandstone, and lignite. Lumped in overlying volcanic unit.","","","MD002","209","Medfra","Sedimentary","1603","TKcg","","" "TKr","Rhyolite and dacite","Early Tertiary and Late Cretaceous","Erosional remnants of rhyolite and dacite domes, sills, dikes, and tuffs that are widely distributed throughout the quad. The rhyolite and dacite of this unit are associated spatially with andesite and basalt flows of unit TKa","","K/Ar ages of 69.1+2.1 Ma and 53.2+1.6 Ma from sanadine, 66.8+2 Ma from hornblende, and 66.4+2 Ma from biotite","UL002","116","Unalakleet","Igneous","1603","","","" "TKi","Shallow intrusive rocks","early Tertiary and Late Cretaceous","Shallow intrusive rocks of silicic and intermediate composition.","","","NR002","75","Norton Bay","Igneous","1603","TKi","","" "TKd","Dacite and rhyolite flows, volcaniclastic and hypabyssal rocks","Tertiary/Cretaceous","Dacite, rhyolite, and trachyandesite lava flows, domes, sills, dikes, and interlayered breccias and tuffs. Composed of phenocrysts of plagioclase, quartz, sanidine, and biotite in a groundmass of quartz and feldspar","Palynoflora collected from coaly layers at the base of the unit in the Medfra quadrangle are latest Cretaceous (Campanian or Maastrichtian) in age","K/Ar isotopic cooling ages for this unit range from 71 to 53 Ma","BT003","136","Bettles","Igneous","1603","TKvr","","" "TKd","Extrusive rocks","Tertiary and or Cretaceous","Dacite and rhyolite flows, domes, and volcaniclastic and hypabyssal rocks","","","RB009","814","Ruby","Igneous","1603","TKd","","" "TKd","Dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks","early Tertiary and Late Cretaceous","Columnar-jointed andesite, basaltic andesite, and basalt lava flows. Composed of phenocrysts of plagioclase and pyroxene in a fine-grained groundmass of plagioclase microlites, granular pyroxene, and dark glass","Palynoflora collected from coaly layers at the base of the unit in the Medfra quadrangle are latest Cretaceous (Campanian or Maastrichtian) in age","K/Ar isotopic cooling ages range from 64 to 54 Ma","UL003","204","Unalakleet","Igneous","1603","","","" "TKv","Volcanic rocks","Late Cretaceous and Early Tertiary","Dacite flows, may include tuff and andesite.","","","TN002","1604","Tanana","Igneous","1604","TKvd","","" "TKv","Volcanic rocks","Late Cretaceous to Early Tertiary","Dacite flows, may include tuff and andesite.","","","TN003","1604","Tanana","Igneous","1604","TKvd","","" "TKn","Volcanic rocks of the Nowitna River area","Latest Cretaceous, Earliest Tertiary","Chiefly subaerial flows of trachyandesite, basaltic andesite, and basalt. Subordinate intercalated flows and tuffs of rhyolite and dacite.","","63 to 64 Ma","MD002","202","Medfra","Igneous","1605","TKvn","","" "TKa","Andesite and basalt","Early Tertiary and Late Cretaceous","Chiefly hornblende andesite, andesite, and basalt lava flows that are widely distributed. Flows are spatially associated with rhyolite and dacite of TKr","","K/Ar ages of 64.4+1.9 Ma, 61.5+1.8 Ma, and 53.8+1.6 Ma","UL002","114","Unalakleet","Igneous","1605","","","" "TKv","Volcanic and Sedimentary rocks","Tertiary (?) and/or Cretaceous (?)","Porphyritic basalt, andesite, and rhyolite flows, tuffs, and breccias with minor intercalated siltstone and sandstone","","","RB004","120","Ruby","Igneous","1605","TKvi","","" "TKa","Andesite and basalt flows and volcaniclastic rocks","Tertiary and Cretaceous","Columnar-jointed andesite, basaltic andesite, and basalt lava flows. Composed of phenocrysts of plagioclase and pyroxene in a fine-grained groundmass of plagioclase microlites, granular pyroxene, and dark glass","","K/Ar isotopic cooling ages range from 64 to 54 Ma","AR003","710","Ambler River","Igneous","1605","TKvi","","" "TKa","Andesite and basalt flows and volcaniclastic rocks","Tertiary and or Cretaceous","Andesite and basalt flows and volcaniclastic rocks","","","RB009","813","Ruby","Igneous","1605","TKa","","" "Kh","Hypabyssal rocks","Cretaceous","Small bodies of primarily dacite and rhyolite porphyry. These intrusives are widespread in volcanic graywacke and mudstone unit (Kgm) and in andesitic rocks (Kv).","","","MZ002","310","Melozitna","Igneous","1620","Kve","","" "TKi","Shallow intrusive rocks of silicic and intermediate composition","Early Tertiary and Late Cretaceous","Includes a wide variety of shallow intrusive rocks including rhyolite, dacite, and andesite plugs, domes, sills, and dikes and larger, more coarsely crystalline bodies of granite, granodiorite, tonalite, and monzonite porphyry.","","","NL003","1655","Nulato","Igneous","1620","","","" "TKv","Volcanic rock","Tertiary to Late Cretaceous","Indian River, Takhakhdona Hills, and Dulbi River areas- light-gray to pink rhyolite tuff, welded (?) tuff, flows, and breccia. Subordinate pumice, dark vitrophyre, and obsidian. In Takhakhdona Hills also includes dark-green to black vesicular basalt flows. Big Creek is dark-green to green dacite and andesite porphyry flows and crystal tuffs. Probabaly correlative with similar flows and tuffs in Tanana and Bettles quads. These unit are Tertiary according to Patton (1998) however large area rhyolitic rocks of TKv in the northeastern part of quad. should still be mapped as TKvr","Obsidian chippings and artifacts found in archeological site in NW AK may have source in obsidian occurrence north of Little Indian River.","Flows in Tanana and Bettles quads have K-Ar date of 58 m.y.","MZ002","2210","Melozitna","Igneous","1620","TKvr","","" "TKi","Shallow intrusive rocks of silicic and intermediate composition","Early Tertiary and Late Cretaceous","Includes a wide variety of shallow intrusive rocks including rhyolite, dacite, and andesite plugs, domes, sills, and dikes and larger, more coarsely crystalline bodies of granite, granodiorite, tonalite, and monzonite porphyry.","","","NL004","405","Nulato","Igneous","1620","","","" "TKc","Mafic to intermediate volcano-plutonic complexes","Early Tertiary and Late Cretaceous","Mafic to intermediate volcano-plutonic complexes","","","OP002","202","Ophir","Igneous","1630","TKiv","","" "TKc","Mafic to intermediate Volcano-plutonic complexes","Latest Cretaceous, earliest Tertiary","Altered basalt, andesite, and trachyandesite porphyry flows and hypabyssal intrusive bodies. Altered mafic and intermediate crystal and lithic tuffs. Subordinate olivine basalt and dacite flows.","","K-Ar ages of 65-71 Ma","MD002","204","Medfra","Igneous","1630","TKiv","","" "TKvc","Volcano-plutonic complexes ","early Tertiary and Late Cretaceous","Complexes composed primarily of altered basalt, andesite, and trachyandesite porphyry lava flows and hypabyssal intrusive bodies. The complexes also contain altered mafic and intermediate crystal and lithic tuffs and subordinate olivine basalt and dacite flows. The flows and hypabyssal rocks are composed of plagioclase and clinopyroxene phenocrysts in a groundmass of fine-grained plagioclase laths, granular pyroxene and dark glass. ","","K/Ar isotopic cooling ages from the unit range from 77 to 65 Ma. ","OP005","202","Ophir ","Igneous","1630","","","" "TKvc","Volcano-plutonic complexes ","early Tertiary and Late Cretaceous","Complexes composed primarily of altered basalt, andesite, and trachyandesite porphyry lava flows and hypabyssal intrusive bodies. The complexes also contain altered mafic and intermediate crystal and lithic tuffs and subordinate olivine basalt and dacite flows. The flows and hypabyssal rocks are composed of plagioclase and clinopyroxene phenocrysts in a groundmass of fine-grained plagioclase laths, granular pyroxene and dark glass. ","","K/Ar isotopic cooling ages from the unit range from 77 to 65 Ma","MD004","204","Medfra","Igneous","1630","","","" "TKi","Mafic and ultramafic intrusive rocks","Cretaceous and (or) Tertiary","Mafic and ultramafic intrusive rocks including pluglike body of augite andesite porphyry and a small dikelike body of augite peridotite","","","HU002","180","Hughes","Igneous","1640","TKum","","" "TKsa","","Latest Cretaceous, earliest Tertiary","Dike-like body of dark-brown to gray andesite porphyry.","","","MD002","208","Medfra","Igneous","1641","TKmd","","" "TKi","Intrusive rocks","Late Cretaceous(?) or Early Tertiary(?)","Granite, diorite, quartz monzonite, and may include dikes of varying composition and texture, older intrusives of the greenstone complex (mi), and hornfelds zones surrounding intrusive rocks. ","","","RB002","201","Ruby","Igneous","1650","TKi","","" "TKcm","Mafic to intermediate volcano-plutonic complexes -- monzonite","Latest Cretaceous, earliest Tertiary","Small bodies of monzonite, quartz monzonite, and granodiorite","","","MD002","203","Medfra","Igneous","1650","TKim","","" "TKi","Shallow intrusive rocks - Complex","early Tertiary and Late Cretaceous","Shallow intrusive rocks of silicic and intermediate composition. Complex of many small intrusive bodies","","","NR002","336","Norton Bay","Igneous","1650","TKi","","" "Tki","Intrusive Rocks","early Tertiary or Late Cretaceous","Granite and some diorite. Includes numerous dikes and sills and may include hornfels zones","","","NL002","1650","Nulato","Igneous","1655","TKg","","" "TKg","Granite","Latest Cretaceous, earliest Tertiary","White to light gray, fine- to coarse-grained biotite granite.","","63-71 Ma","MD002","211","Medfra","Igneous","1655","TKg","","" "TKq","Quartz monzonite","Early Tertiary-Late Cretaceous","Light- to vey light-gray quartz monzonite, may range to granite","","K-Ar(?) 61.8 Ma","TN002","1655","Tanana","Igneous","1655","TKg","","" "TKg","Granitic rocks, undivided","Late Cretaceous to Early Tertiary","Light- to vey light-gray quartz monzonite, may range to granite.","","K-Ar(?) 61.8 Ma","TN003","1655","Tanana","Igneous","1655","TKg","","" "Kg","Granitic rocks","Late Cretaceous?","Granodiorite","","K-Ar date of 81.5 to 89.0 Ma from similar plutons in Melozitna quad., however later data suggests Latest Cretaceous or Early Tertiary age from Nulato quadrangle.","RB004","2410","Ruby","Igneous","1655","TKg","","" "TKg","Granite","Cretaceous-Tertiary","Medium- to coarse-grained equigranular to porphyritic biotite granite composed of anhedral quartz, anhedral to euhedral (porphyritic variety) K-feldspar, anhedral plagioclase and subhedral biotite","","K-Ar age of 65.5 +/- 3.3 m.y. from biotite","RB007","110","Ruby","Igneous","1655","TKg","","" "TKg","Granite-granodiorite","Tertiary to Cretaceous","Granite-granodiorite","","","RB009","815","Ruby","Igneous","1655","TKg","","" "TKg","Granitic rocks","Tertiary and or Cretaceous","Granitic rocks of acidic and intermediate composition. Cheifly syenite at Roundabout Mountain and albite granite on Huslia River-Derby Creek divide. Maybe other small unmapped granitic bodies intruding andesitic volcanic rocks in northwestern part of quadrangle","","","KT002","600","Kateel River","Igneous","1655","","","" "TKm","None","Early Tertiary and Late Cretaceous","Monzonite","","","OP002","203","Ophir","Igneous","1660","TKm","","" "TKm","Monzonite","Latest Cretaceous, earliest Tertiary","Includes monzonite, quartz monzonite, quartz monzodiorite, and monzodiorite. Subordinate monzogabbro and gabbro","","66-70 Ma","MD002","205","Medfra","Igneous","1660","TKm","","" "TKm","Diorite, monzonite, and quartz syenite","Latest Cretaceous, earliest Tertiary","Light to medium-gray biotite-aegerine-olivine diorite, monzonite, and subordinate quartz syenite. Forms bulk of Cripple Creek Mountains pluton.","","K-Ar age of 71.3 Ma","MD003","1660","Medfra","Igneous","1660","TKm","","" "TKm","Diorite, monzonite, and quartz syenite","Latest Cretaceous, earliest Tertiary","Light to medium-gray biotite-aegerine-olivine diorite, monzonite, and subordinate quartz syenite. Forms bulk of Cripple Creek Mountains pluton.","","K-Ar age of 71.3 Ma","OP003","1660","Medfra","Igneous","1660","TKm","","" "TKm","Monzonite","early Tertiary and Late Cretaceous ","Medium- to coarse-grained, equigranular, biotite and hornblende monzonite, quartz monzonite, monzodiorite, and quartz diorite. Subordinate monzogabbro and gabbro.","","K/Ar isotopic cooling ages from this unit range from 70 to 66 Ma.","OP005","203","Ophir ","Igneous","1660","","","" "TKm","Monzonite ","early Tertiary and Late Cretaceous ","Medium- to coarse-grained, equigranular, biotite and hornblende monzonite, quartz monzonite, monzodiorite, and quartz diorite. Subordinate monzogabbro and gabbro. ","","K/Ar isotopic cooling ages from this unit range from 70 to 66 Ma.","MD004","205","Medfra","Igneous","1660","","","" "TMg","None","Tertiary or Late Cretaceous (Not designated on map)","Gabbro","","","OP002","205","Ophir","Igneous","1680","TDg","","" "TDg","Undifferentiated gabbro","Devonian to Tertiary","Sills, dikes, and small plutons of gabbro intruding rocks of early Paleozoic and preCambrian(?) age","","","MD002","210","Medfra","Igneous","1680","TDgb","","" "TDg","Gabbro","Tertiary","Gabbro","","","RB009","816","Ruby","Igneous","1680","TDg","","" "TDg","Gabbro and diabase ","Tertiary? to Devonian?","Fresh to altered gabbroic and diabasic intrusive bodies. Unit intrudes rocks as old as middle Paleozoic and as young as Cretaceous. May represent a wide range of ages.","","","HU003","2210","Hughes ","Igneous","1680","","","" "TDg","Gabbro and diabase","Tertiary? to Devonian?","Fresh to altered gabbroic and diabasic intrusive bodies. Unit intrudes rocks as old as middle Paleozoic and as young as Cretaceous. May represent a wide range of ages ","","","OP002","5901","Ophir","Igneous","1680","PzZrqs","","" "Klc","Limestone conglomerate","Cretaceous","Pebble to boulder limestone conglomerate, poorly sorted, locally derived, non-marine","plant fossils of Cretaceous age","","CA002","400","Candle","Sedimentary","1815","Kccc","","" "Kcc","Carbonate-rich conglomerate and sandstone","Late and Early Cretaceous","Nonmarine and marine carbonate-rich conglomerate and sandstone deltaic deposits.","","","NR002","726","Norton Bay","Sedimentary","1815","Kcc","","" "Kcc","Calcareous graywacke and mudstone","Cretaceous","Cyclically interbedded sequence of fine to coarse grained, calcareous graywacke, fine to medium grained carbonaceous, volcanic graywacke, and carbonaceous mudstone. This unit has been lumped with the eastern part of unit Kcv on the source map and re-labeled (W.W. Patton, Jr., 1999)","abundant carbonized plant debris","","CA002","232","Candle","Sedimentary","1820","Kcvg","","" "Kcvg","Carbonaceous volcanic graywacke and mudstone turbidite deposits","Early Cretaceous","Carbonaceous volcanic graywacke and mudstone turbidite deposits","","","NR002","334","Norton Bay","Sedimentary","1820","Kcvg","","" "Kcv","Calcareous graywacke and mudstone","Cretaceous","Mixed sequence of calcareous graywacke, calcareous mudstone, volcanic graywacke, and volcanic conglomerate. Transitional between Kvg and Kcg. Unit added by Patton, 1999 by sub-division. Consists of carbonaceous volcanic graywacke and mudstone turbidite deposits. Much of the eastern part of this unit has been lumped with unit Kcc on the source map and re-labeled (W.W. Patton, Jr., 1999)","abundant carbonized plant debris","","CA003","230","Candle","Sedimentary","1820","Kcvg","","" "Kg","Volcaniclastic graywacke and mudstone turbidites","Early Cretaceous","Reassignment of part of unit in extreme northwest part of quadrangle (W.W. Patton, Jr., written commun., 1999). Dark-gray to green, hard, fine-grained to conglomeratic volcanic graywacke and dark-gray, finely laminated mudstone. Turbidite assemblage consisting of submarine-fan deposits, chiefly midfan channel, interchannel, and related overbank facies","","","UL003","103","Unalakleet","Sedimentary","1820","","","" "Kv","Volcanic graywacke and mudstone","late Early Cretaceous (Albian)","Poorly sorted dark greenish-gray volcanic graywacke and mudstone. Reclassified in northwestern part of quadrangle from NSA = 2180","","","SH003","17","Shungnak","Sedimentary","1820","Kcvg","","" "Kcvg","Carbonate and volcanic clast graywacke and mudstone","late Early Cretaceous (Albian)","Cyclically interbedded fine- to coarse-grained highly calcareous graywacke; hard, fine- to medium-grained, carbonaceous, volcanic graywacke; and dark carbonaceous mudstone. Graywacke is typically graded and sole-marked. Carbonized plant debris is abundant. Graywacke/mudstone ratios are generally high. The unit is interpreted to represent middle and outer submarine fan lobe deposits; some locally thick sections of mudstone probably represent basin plain deposits. Paleocurrents are generally to the northeast. Unit appears to be transitional between the carbonate-rich deposits of map unit Kcg and the volcanic-rich deposits of map unit Kvg. ","Shallow-water marine mollusks locally abundant but poorly preserved, probably of Early Cretaceous (Albian) age.","","SE004","3004","Selawik","Sedimentary","1820","Kcvg","","" "Kcvg","Carbonate- and volcanic-clast graywacke and mudstone submarine fan deposits.","Cretaceous","Cyclically interbedded fine- to coarse-grained highly calcareous graywacke; hard, fine- to medium-grained, carbonaceous, volcanic graywacke; and dark carbonaceous mudstone. Graywacke is typically graded and sole-marked. Carbonized plant debris is abundant. Graywacke/mudstone ratios are generally high. The unit is interpreted to represent middle and outer submarine fan lobe deposits; some locally thick sections of mudstone probably represent basin plain deposits. Paleocurrents are generally to the northeast. Unit appears to be transitional between the carbonate-rich deposits of map unit Kcg and the volcanic-rich deposits of map unit Kvg. ","Poorly preserved marine mollusks of late Early Cretaceous (?) age are present in this unit in the Selawik quadrangle","","BM003","1820","Baird Mountains","Sedimentary","1820","Kcvg","","" "Kcg","Calcareous graywacke and mudstone","Cretaceous","Rhythmically interbedded, medium-gray, yellowish-orange weathering, fine-grained to gritty highly calcareous graywacke and micaceous, calcareous mudstone. Abundant carbonized plant debris. Unit coarsens westward. Estimated more than 5,000 feet thick.","abundant carbonized plant debris","","CA002","235","Candle","Sedimentary","1821","Kcg","","" "Kct","Carbonate-rich sandstone, siltstone, and shale turbidite deposits","Late and Early Cretaceous","Carbonate-rich sandstone, siltstone, and shale turbidite deposits","","","NR002","728","Norton Bay","Sedimentary","1821","Kcg","","" "Kcg","Carbonate-clast graywacke and mudstone ","Cretaceous","Fine-grained to gritty graywacke and laminated micaceous mudstone turbidite deposits composed largely of carbonate detritus and lesser amounts of quartz, chert, volcanic rock, and mica clasts. Contains abundant carbonized plant debris. The mudstone intervals typically display fine, convolute, cross laminations and current rippled partings. Unit grades from a high graywacke/mudstone ratio on the southwest to a low graywacke/mudstone ratio on the northeast; paleocurrent directions are to the northeast. The abundance of detrital carbonate, quartz, and mica fragments suggest that the unit was derived largely from carbonate rocks and schist units (|cs and |