(!¬NSACLASSNLABELCNAMECˆAGEC$DESCRIPTIOCþSYMBOLNOVERPRINTNSOURCESCô 100 Qu Unconsolidated and poorly consolidated sediments, undivided Quaternary Surficial material deposited by water, wind, freeze-thaw cycles, and glaciers 40 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 640 Ts Clasitc sedimentary rocks Tertiary Mudstone, coal, sandstone, and conglomerate deposited in lacustrine and fluvial environments exposed in the southern, western, and northeastern part of the map area. In the southern and western part of the map area, sandstone and conglomerate are common,70 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 1056Tb Basalt flows and rare cinder cones Tertiary Vesicular, massive olivine basalt flows that range from 20 to 300 m thick exposed in the northeastern and northwestern parts of the map area, in the Brooks Range and Porcupine provinces. The best exposed and studied localilties are in the northeast (Cole142 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 1103Tv Volcanic rocks Tertiary Locally thick packages that include basalt, andesite, dacite, and rhyolite flows and domes exposed in the southwestern part of the map area, all in the Brooks Range province. The largest accumulation of these rocks is on the west side of the Ruby geanti14 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 1320Tg Granitic rocks Tertiary Quartz monzonite, biotite granite, and alaskite exposed in the Rampart area of the Brooks Range province and in the Yukon-Tanana province. The two bodies in the Rampart area exposed between the Yukon River and Victoria Creek fault locally have igneous li27 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 1510TKs Sedimentary rocks Tertiary and Cretaceous Sandstone, mudstone, thin coal seems, and conglomerate exposed in the Takonduk and Rampart areas. In the Tatonduk area, the unit occurs just east of the Kandik basin and along the Tintina fault zone. Late Cretaceous, Paleocene, and Eocene pollen have bee260 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 2030Kkyu Sedimentary rocks of the Yukon-Koyukuk basin, undivided Cretaceous Marine volcanic-clast conglomerate, graywacke, sandstone, mudstone, shale, calcareous sandstone, siltstone and shale, and minor non-marine sandstone and shale. Exposed in along the western boundary of the map. Mollusks from the marine part of the unit a592 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 2122Kku Sedimentary rocks of the Kandik basin, undivided Cretaceous Carbonaceous shale, siltstone, quartz arenite, argillite, graywacke, sandstone, and conglomerate; parts of the section are rich in volcanic clasts. Early Cretaceous (Valanginian and Berriasian) megafossils have been identified. Although correlations hav494 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 2492Kg Granitic rocks Cretaceous Small plugs to large, batholithic plutons, largely of mid-Cretaceous age, exposed in the Ruby geanticline, Manley basin, and Yukon-Tanana Upland. Ruby geanticline plutons are generally evolved and yield U-Pb zircon and K/Ar ages of 112-90 Ma (Patton and99 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 2810KJu Sedimentary rocks, undifferentiated Cretaceous? and Jurassic? Scattered occurrences of shale, argillite and quartzite up to 300m thick exposed in central and northern part of Porcupine province (Brosg‚ and Reiser, 1969; Brabb, 1970). Bivalves of Jurassic or Cretaceous age reported from one exposure in the Coleen qu450 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 2860Mzmv Fine-graned sedimentary rocks and tuff Cretaceous? and Jurassic? Slate, shale, siltstone, argillite, tuff, and minor quartzite and conglomerate exposed just south of the Tintina fault system and immediately northeast of the Manley basin. No direct age control. Equivalent to the Vrain unit ("KJv") of Weber and others 964 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 2861KJg Glenn Shale, upper part Late Cretaceous and Jurassic? Carbonaceous shale that contains minor thin (up to 5m) beds of fine-grained sandstone, exposed in the southern part of the Porcupine province. Depositionally overlain by sedimentary rocks of the Kandik basin (Kku). Early Cretaceous megafossils have been952 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 3270JMsu Strangle Woman Creek sequence of Brosge' and Reiser (1969), undivided Jurassic to Mississippian Rock types include very fine grained to conglomeratic sandstone; gray limestone and dolostone; dark gray, very fine grained, thin-bedded limestone and black chert; and coarse-grained, conglomeratic, quartz sandstone that contain minor potassium feldspar,532 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 3280JMpu Younger strata of the Porcupine River sequence of Brosge' and Reiser (1969), undivided Jurassic to Mississippian Main rock types are ferruginous, very fine grained sandstone; gray to black pyritic siltstone and silty shale; laminated, red and green chert; silty, shaly, and cherty limestone; coarse-grained to conglomeratic, locally feldspathic sandstone, mafic flows452 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 4730KJmu Sedimentary rocks of the Manley basin, undivided Cretaceous and Jurassic Quartzite, shale, siltstone, graywacke, polymictic conglomerate exposed in the western part of the province. Equivalent to the Minto, Wilber Creek, and Wolverine quartzite units of Weber and others (1992) and the Manley terrane of Jones and others (1987560 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5012TrPs Sedimentary rocks Triassic? to early Permian Argillite, siltstone, sandstone, shale, chert, limestone, conglomerate, and limestone debris flows exposed along the southwestern margin of the Manley basin. The unit is structurally imbricated with the sedimentary rocks of the Manley basin (KJmu). Conod340 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5035TrPgtGlenn Shale, lower part, and Tahkandit Limestone, undivided Triassic and Permian Thin-bedded fossiliferous limestone, calcareous shale and rare thin oil shale of the lower part of the Glenn Shale, and massive bioclastic limestone, glauconitic sandstone, and minor chert pebble conglomerate of the Tahkandit Limestone. Most of the expos720 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5036PCta Sedimentary rocks of the Tatonduk area Permian to Cambrian Limestone, argillite, shale, chert, quartz arenite and conglomerate exposed in the southern part of the Porcupine province. The sequence includes several formal stratigraphic units, which are not enumerated here (see Dover, 1994). Lower Paleozoic rock514 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5133JDat Angayucham-Tozitna terrane, undivided Late Jurassic to Devonian Lithologically diverse, structurally imbricated igneous and sedimentary rocks of oceanic affinity exposed on all flanks of the Yukon Flats basin. Igneous rocks include ultramafic, mafic extrusive and intrusive, andesitic, and rare dacitic to rhyolitic ig306 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5209MzPzaLow-grade metamorphic rocks Mesozoic? and Paleozoic Phyllite, argillaceous metachert, limestone, and associated mafic rocks. Exposed only in southeast part of the map area adjacent to Tintina fault. Includes some areas dominated by argillite, equivalent to "Mza" of Foster (1992), and other lithologically 322 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5213TrPzdMetasedimentary and metavolcanic rocks, sedimentary rocks of the Doonerak area Triassic to late Paleozoic Fine-grained metasedimentary rocks that contain lenticular bodies of carbonate rocks; metavolcanic and metavolcaniclastic rocks of island arc affinity, and a thin sequence of shale, siltstone and limestone (Dillon and others, 1986; Moore and others, 199956 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5335Pzvu Sedimentary rocks of the Venetie terrane of Silberling and others (1994), undivided Paleozoic Lithic and quartz wacke, metamorphosed wacke, metasandstone, phyllite, slate, shale, quartzite, chert, and minor greenstone (Brosg‚ and Reiser, 2000). Devonian (?) plants and spores, Mississippian (?) Radiolaria, and Permian conodonts have been recovere445 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5335Pzcm Metamorphic rocks Paleozoic? Semischist, phyllite, and thin layers of mafic rock exposed in the extreme northeast corner of the Porcupine province. Rocks are generally fine grained, and the metamorphic assemblage locally includes biotite and garnet. Contact with adjacent granite is477 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5470Pzum Ultramafic rocks Paleozoic? Serpentinite and lesser gabbro and rodingite rubble limited to one small area in the southwest part of the province. Based on trace element data, Reifenstuhl and others (1998) considered these rocks to have formed originally in an oceanic arc or ridge se429 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5560DZs Metamorphosed sedimentary rocks Devonian to Proterozoic Variably metamorphosed and deformed shale, siltstone, fine- to medium-grained sandstone, graywacke, quartz and chert wacke, and minor conglomerate, carbonate, and mafic rocks. Quartz-rich rocks that contain chert clasts are common. Sedimentary structure435 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5561DZs Metamorphosed sedimentary rocks Devonian to Proterozoic Variably metamorphosed and deformed shale, siltstone, fine- to medium-grained sandstone, graywacke, quartz and chert wacke, and minor conglomerate, carbonate, and mafic rocks. Quartz-rich rocks that contain chert clasts are common. Sedimentary structure435 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 5965Pzqs Sedimentary and igneous rocks Permian, Carboniferous, and DevonianQuartz-rich sedimentary rocks, associated carbonate rocks and minor mafic volcanic rocks. The quartz-rich rocks are by far the most common lithologies and consist of chert arenite, quartz-chert wacke, quartzite, chert-pebble conglomerate, minor mudstone412 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 6300KDe Sedimentary rocks of the Endicott Mountains allochthon of Moore and others (1994) Cretaceous to Devonian Thick marine and non-marine sedimentary sequence dominated by Devonian and Mississippian clastic and carbonate rocks of the Endicott and Lisburne Groups (Moore and others, 1994) 958 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 6328Mbu Rocks of Bruooks Range sequence of Brosge' and Reiser (2000), undivided Mississippian Consists of gray to brown, fine- to medium-grained, partly crinoidal limestone (Lisburne Group); black shale, laminated siltstone, chert, and orange-weathering limestone (Kayak Shale); and unnamed black siltstone and shaly phosphatic limestone (Brosg‚ an956 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 6970DCpu Older strata of the Porcupine River sequence of Brosge' and Reiser (1969), undivided Devonian to Cambrian Succession includes dark gray limestone and lesser dolostone that contains Middle Devonian corals; the Salmontrout Limestone of Early Devonian age (Churkin and Brabb, 1965); and light to dark gray, locally mottled dolostone and limestone of Silurian and 513 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 6990DSc Metamorphosed sedimentary rocks Devonian and Silurian Chert and chert-pebble conglomerate, calcarenite, conglomeratic limestone, limestone, metasiltstone and argillite, mafic intrusive rocks, and rare dolostone exposed between the Tintina fault zone and the Yukon Flats basin, in the northern part of the Yuk434 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 7050Cg Granite Carboniferous Granite and quartz monzonite, exposed in large body on the northeast boundary of the map. Northern contact with adjacent metamorphic rocks is intrusive; southern boundary is shown as a fault but is not well exposed nor well understood. K/Ar mica ages ra44 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 7990CPt Sedimentary rocks of the Tindir Group Cambrian? and Proterozoic Phyllite, slate, siltstone, argillite, quartzite, red beds, carbonate-clast conglomerate, dolostone, limestone, basalt, chert, and glacial diamictite exposed in the southeast part of the Porcupine province. See Dover (1994) for a summary of the formal u601 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 8440PzZl Sedimentary and igneous rocks corresponding to the Livengood area swquence of Weber and others (1992) Paleozoic to Proterozoic Argillite, phyllite, quartzite, graywacke, siltite, grit and limestone of the Wickersham unit, mafic intrusive and extrusive rocks and fine grained sedimentary rocks interlayered with serpentinite, equivalent to "PzZm" and "CZum" units; dolomite, chert, 475 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 8441PzZw Sedimentary and igneous rocks corresponding to the older parts of the Fairbanks-White Mountains area sequence of Weber and others (1992)Paleozoic to Proterozoic Argillite, grit, quartzite, graywacke, phyllite, limestone, and dolomite, equivalent to the Wickersham unit; alkali basalt, agglomerate, volcanic conglomerate, and associated limestone, sandstone and chert, equivalent to the Fossil Creek Volcanics; muds266 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 8442PzZs Sedimentary and igneous rocks corresponding to older parts of the Schwatka-Rampart area sequence of Webber and others (1992) Paleozoic to Proterozoic Grit, argillite, quartzite, siltite, graywacke, phyllite, and minor limestone; interlayered mafic volcanic rocks and limestone, minor associated greenstone, limestone, and limestone debris flows, and a group of fine-grained metamorphic and sedimentary ro364 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 8630PzpCyMetamorphic rocks of the Yukon-Tanana Upland, undivided Paleozoic to Precambrian? Fault-bounded assemblages of lithologically and metamorphically distinct metaigneous and metasedimentary rocks that have Paleozoic and Precambrian(?) protoliths exposed in the south-central part of the map (Dusel-Bacon and others, 2002). Structurally lo65 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 8850PzpChMetasedimentary and metaigneous rocks of the Hammond terrane Paleozoic and (or) Precambrian Thick sequences of lower Paleozoic metacarbonate rocks commonly called the Skajit Limestone (Moore and others, 1994), thick sequences of metasiliciclastics, metamorphosed calcareous sedimentary rocks, and minor mafic metagabbro and metafelsite exposed im322 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 8852PzpCmMetamorphic rocks Paleozoic and (or) Precambrian? Pelitic schist, amphibolite, metaquartzite, marble, and granitic orthogneiss that occur as three lenses in or near the Kobuk and Victoria Creek fault systems. Not all lithologies are found in all three lenses. Protolith ages are unknown. Metamorphic 95 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000. 9325PzpCbMetasedimentary and metaigneous rocks of the southern Brooks Range and Ruby geanticline Paleozoic and (or) Precambrian Quartz-mica schist and lesser calcareous schist, marble, mafic schist, and granitic orthogneiss, exposed along the southern Brooks Range and axis of the Ruby geanticline. Early Devonian microfossils were collected from marble in the Wiseman quadrangle (53 Till, A.B., Dumoulin, J.A., Phillips, J.D., Stanley, R.G., Crews, Jesse, in prep., Generalized bedrock geologic map, Yukon Flats region, east-central Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-XXX, scale 1:500,000.