JáØLABELCNSACLASSNNAMECªAGEC&DESCRIPTIOCþSOURCESCþ Da 7260Ambler sequence, Schist belt Devonian Interlayered white- to medium-gray-weathering metarhyolite, dark-green-weathering metabasite, pale-gray-weathering marble, and brown- to dark-gray-weathering calcareous, pelitic and carbonaceous schist exposed in two areas in the Schist belt. The unit ocTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dg 7250Granitic orthogneiss Devonian Tan- to gray-weathering, equigranular to porphyroblastic, fine- to coarse-grained metagranitic bodies ranging in size from less than a kilometer to over 20 km across, found in both the Schist and Central belts. Generally granitic in composition and madeTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dhf 6925Hunt Fork Shale, Central belt and part of Northern thrust assemblages Late Devonian Dark-gray to black phyllite and lesser gray-green phyllite with thin layers of siliceous or calcareous metasiltstone, lithic wacke, metasandstone, and minor layers of fossiliferous metalimestone exposed along the length of the northern boundary of the maTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dhf* 7225Hunt Fork Shale, strongly foliated, Central belt and part of Northern thrust assemblages Late Devonian Dark-gray to black phyllite and lesser gray-green phyllite with thin layers of siliceous or calcareous metasiltstone, lithic wacke, metasandstone, and minor layers of fossiliferous metalimestone exposed along the length of the northern boundary of the maTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dl 6927Metalimestone, Central belt and part of Northern thrust assemblages Devonian Metalimestone and lesser metasandstone, metasiltstone, phyllite, and minor conglomerate. Dl includes limestone of Nakolik River (map unit Dnl) of Karl and others (1989b) in the Baird Mountains quadrangle, limestone layers in the Chandalar quadrangle calTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dmu 6927Metasedimentary and lesser metaigneous rocks, Central belt and part of Northern thrust assemblages Middle and Late Devonian Heterogeneous expanses of calcareous, siliceous, and volcaniclastic metasedimentary rocks, with lesser metaigneous rocks, exposed along the length of the Central belt. Includes interlayered gray, maroon, purple and green siliceous phyllite, brown and blTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dmu 6973Metasedimentary and lesser metaigneous rocks, volcanic-rock bearing subunit, Central belt and part of Northern thrust assemblages Middle and Late Devonian Parts of the unit containing felsic to intermediate volcanic rocks or sedimentary rocks with abundant volcanic clasts are shown with a vertical line overlay. Heterogeneous expanses of calcareous, siliceous, and volcaniclastic metasedimentary rocks, withTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dmu 6972Metasedimentary and lesser metaigneous rocks, Central belt and part of Northern thrust assemblages, Ferriginuous and Calcareous schist Middle and Late Devonian Relatively lithologically simple section in the north and northeast Survey Pass quadrangle consisting of light brown, gray, and orange-weathering ferruginous and calcareous mica schist, phyllite, and metasiltstone is shown with a diagonal line overlay. Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dn 6900Noatak Sandstone, Central belt and part of Northern thrust assemblages Devonian Metasandstone, metasiltstone, and subordinate phyllite exposed in the northern Baird Mountains, Ambler River, and Survey Pass quadrangles; part of Endicott Group (Tailleur and others, 1967). The unit was established by Smith (1913); Dutro (1952) designatTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DOb 6980Baird Group, Central belt and part of Northern thrust assemblages Devonian to Ordovician Beige- to orange-weathering, laminated, partly argillaceous to silty metalimestone and light- to dark-gray, flaggy-bedded to massive metalimestone, marble, and dolostone. DOb is part of the Nakolik River sequence of Karl and others (1989b). The Baird GroTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DOc 6980Younger carbonate rocks of the Nanielik antiform, Central belt and part of Northern thrust assemblages Middle Devonian to Ordovician Very light- to dark-gray- (locally orange-) weathering, gray to black, commonly massive dolostone and lesser metalimestone and marble exposed in the Nanielik antiform (northeastern Baird Mountains and northwestern Ambler River quadrangles) and in the norTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DpCgn 7361Schist and paragneiss, Arrigetch-Igikpak thermal high Devonian to Proterozoic? Pelitic schist, metaquartzite, mafic schist and other lithologies; gneissic textures are particularly common where the unit is adjacent to metaplutonic rocks. Mafic rocks within the unit contain assemblages stable in the albite-epidote-amphibolite facieTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DpCm 8852Metamorphic rocks, Mosquito terrane Devonian to Proterozoic? Pelitic schist, metabasite, minor felsic orthogneiss and meta-ultramafic rock exposed in two small areas along the Kobuk fault zone in the northeastern Bettles and southwestern Chandalar quadrangles. The rocks exhibit amphibolite-facies metamorphic asseTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DpCsc 8605Calcareous schist, Schist belt Devonian to Proterozoic Light-gray-, brown- and locally orange-weathering, lithologically heterogeneous mix of marble and carbonate-rich, quartz-rich, and mafic schist derived from metasedimentary and metaigneous protoliths; one of two major units that extends along the length Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DpCsc 8607Calcareous schist, albite-rich subunit, Schist belt Devonian to Proterozoic Light-gray-, brown- and locally orange-weathering, lithologically heterogeneous mix of marble and carbonate-rich, quartz-rich, and mafic schist derived from metasedimentary and metaigneous protoliths; one of two major units that extends along the length Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DpCsc 8608Calcareous schist - metachert and conglomerate subunit, Schist belt Devonian to Proterozoic Light-gray-, brown- and locally orange-weathering, lithologically heterogeneous mix of marble and carbonate-rich, quartz-rich, and mafic schist derived from metasedimentary and metaigneous protoliths; one of two major units that extends along the length Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DpCsm 7360Schist and marble, undivided, Arrigetch-Igikpak thermal high Devonian to Proterozoic? Gray marble, orange dolomitic marble, magnetite-bearing chlorite schist, and pelitic schist exposed in the central Survey Pass quadrangle. Lithologies are interlayered and isoclinally folded, and the unit has a bedded appearance due to layers of resistaTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dps 6900Lithic sandstone and shale, Phyllite belt Devonian Dominantly gray-green lithic sandstone, lesser brown quartz sandstone, and black shale and silty shale exposed in the western Christian quadrangle (Brosg‚ and Reiser, 2000). Sandstones are fine- to medium-grained and thin- to medium-bedded. Black shaleTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dps 7200Schistose lithic sandstone and shale, Phyllite belt Devonian Schistose varieties are equivalent to units "Dmw" and "Dpm" of Brosg‚ and Reiser (2000). Dominantly gray-green lithic sandstone, lesser brown quartz sandstone, and black shale and silty shale exposed in the western Christian quadrangle (Brosg‚ and ReisTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? DSc 6927Carbonate rocks of Cosmos Hills, Cosmos Hills sequence Devonian and Silurian Thin-bedded to massive dolostone, metalimestone, and marble, locally graphitic or phyllitic, exposed in fault slices in the Cosmos Hills, Shungnak and Ambler River quadrangles. The unit includes minor thin, micaceous layers interpreted as airfall tuffs, Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Dsq 8602Quartz-mica schist, Schist belt Devonian Gray, dark-gray, or brownish-gray weathering, dominantly pelitic or semipelitic schist that constitutes the major lithologic unit of the Schist belt. Outcrops vary from blocky and resistant (quartz-rich varieties) to platy and less resistant (mica-rich Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? JCs 5003Sedimentary rocks, Central belt and part of Northern thrust assemblages Jurassic to Carboniferous Sandstone, shale, argillaceous limestone, limestone, dolostone, mudstone, chert and siltstone in north-central Wiseman quadrangle. The unit conformably overlies the Kanayut Conglomerate (Bowsher and Dutro, 1957) of the Endicott Group (Tailleur and otherTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? JDab 5133Mafic metavolcanic and metaintrusive rocks, metachert, metalimestone, and amphibolite of the Angayucham terrane, Angayucham Terrane, Serpentinite, And Yukon-Koyukuk BasinEarly Jurassic to Devonian Metamorphosed pillow basalt, hyaloclastic breccia, basaltic tuff, diabase, microgabbro, radiolarian and tuffaceous chert, minor metalimestone, and rare mafic schist in an imbricate package exposed along the southern boundary of the map area. The package Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? JDab 5140Mafic metavolcanic and metaintrusive rocks, metachert, metalimestone, and amphibolite of the Angayucham terrane, Angayucham Terrane, Serpentinite, And Yukon-Koyukuk BasinEarly Jurassic to Devonian Metamorphosed pillow basalt, hyaloclastic breccia, basaltic tuff, diabase, microgabbro, radiolarian and tuffaceous chert, minor metalimestone, and rare mafic schist in an imbricate package exposed along the southern boundary of the map area. The package Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? JDk 5001Rocks of the Kivivik Creek sequence, Central belt and part of Northern thrust assemblages Jurassic to Devonian Consists, in ascending order, of Devonian marine sedimentary rocks equivalent to unit Dmu, sandstone, conglomerate, and shale of the Endicott Group (Devonian and Mississippian), limestone and tuff (Mississippian), chert and phyllite (Carboniferous), and Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Kg 2492Granitic rocks Cretaceous Granite, quartz monzonite, and granodiorite of the northern Ruby terrane, exposed along the southern boundary of the Chandalar quadrangle (Brosg‚ and Reiser, 1964). K-Ar dates range from 103ñ6 to 110ñ6 Ma (Blum and others, 1987) Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Khs 2650Hammond River shear zone, Central belt and part of Northern thrust assemblages Cretaceous? Heterogeneous mix of finely laminated, mostly mylonitic lithologies derived in part from adjacent units exposed in the eastern Wiseman and western Chandalar quadrangles. Unit is recessive, poorly exposed, and includes large (up to 0.5 km across) bodies Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? KJm 5145Melange, Phyllite belt Cretaceous to Jurassic Tectonic assemblage of meter to kilometer-scale fault slivers of pillow basalt, mafic schist, metagabbro, metalimestone, metachert, metamorphosed lithic sandstone, phyllite, and rare serpentinite exposed in low hills in the south central and southwesternTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Km 2610Migmatite Cretaceous Intermixed granitic rocks, biotite schist, and hornblende hornfels; pyroxene hornfels and granitic dikes, associated with Cretaceous granitic rocks. All exposed in the northern Ruby terrane, along the southern margin of the Chandalar quadrangle (Brosg‚ Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Ks 1990Conglomerate, sandstone, and shale, Angayucham Terrane, Serpentinite, and Yukon-Koyukuk Basin Cretaceous Conglomerate and finer grained sedimentary rocks exposed along the southern map boundary. The unit varies in character from massive, poorly stratified rocks rich in mafic intrusive and extrusive clasts at the base of the unit to well-sorted sedimentary rTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Kvg 2180Volcanic lithic sandstone and mudstone, Angayucham Terrane, Serpentinite, and Yukon-Koyukuk Basin Cretaceous Fine-grained to conglomeratic sandstone and fine-grained laminated mudstone exposed along the south-central boundary of the map. Mudstone is locally tuffaceous. Clasts are predominantly intermediate and mafic volcanic and intrusive rocks and chert with Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Mc 6360Quartz-rich conglomerate, Central belt and part of Northern thrust assemblages Mississippian? Quartz- , chert-, quartzite-, and slate-clast conglomerate with minor thin layers of metasandstone and phyllite exposed in the Ambler River, Survey Pass, and Wiseman quadrangles. Quartz and chert clasts are most common; chert clasts are varicolored. ThTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Mcp 6200Carbonaceous chert and siliceous phyllite, Central belt and part of Northern thrust assemblages Mississippian Black carbonaceous metachert and siliceous phyllite exposed in a small area in the northwestern Baird Mountains quadrangle. Local layers of black carbonaceous metalimestone contain conodonts of Devonian-Mississippian age (Table A-1). The unit likely forTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? MDe 6300Endicott Group, undivided, Central belt and part of Northern thrust assemblages Mississippian and Devonian Shale and sandstone exposed in the northwest Baird Mountains quadrangle. Represents undifferentiated parts of the Endicott Group that are equivalent to the Hunt Fork Shale (unit Dhf), the Noatak Sandstone (unit Dn) and the Mississippian Kayak Shale (parTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? MDer 6982Eli River sequence, Northern thrust assemblages Mississippian and Devonian Dolostone, limestone, argillaceous or sandy limestone, sandstone, and limestone and dolostone with chert that make up the Eli River sequence of Karl and others (1989b). MDer consists of unnamed Middle Devonian carbonate rocks (here excluded from the BaiTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? MDk 6915Kanuyut Conglomerate, Central belt and part of Northern thrust assemblages Early Mississippian? and Late DevonianQuartz conglomerate, quartzite, metasandstone, phyllite, shale, and metalimestone in the Ambler River, Survey Pass, and Wiseman quadrangles. Includes metasiliciclastic and metacarbonate strata in Ambler River and Survey Pass quadrangles, most with few tTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? MDk 6916Kanuyut Conglomerate, Central belt and part of Northern thrust assemblages Early Mississippian? and Late DevonianQuartzite, pebbly quartzite, conglomerate, and minor siltstone. MDk is exposed in a few small areas in the northwestern Baird Mountains quadrangle and the northeastern Ambler River quadrangle, and is widely distributed in northern Survey Pass quadrangleTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? MDk_1016914Kanuyut Conglomerate, Central belt and part of Northern thrust assemblages Early Mississippian? and Late DevonianQuartz conglomerate, quartzite, metasandstone, phyllite, shale, and metalimestone in the Ambler River, Survey Pass, and Wiseman quadrangles. Includes metasiliciclastic and metacarbonate strata in Ambler River and Survey Pass quadrangles, most with few tTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Mkkl 6305Kekiktuk Conglomerate(?), Kayak Shale of Endicott Group, and Lisburne Group, Central belt and part of Northern thrust assemblages Mississippian Quartzite, conglomerate, phyllite, metalimestone, slate, dolostone, marble, and chert. The succession occurs in several fault-bounded exposures in the east-central Ambler River quadrangle. Within the fault-bounded exposures, the intensity of deformationTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Mkl 6328Kayak Shale of Endicott Group and Lisburne Group, Central belt and part of Northern thrust assemblages Mississippian Phyllite or slate, siltstone, sandstone, limestone, and chert exposed in two small areas in the northwestern Baird Mountains quadrangle and in a larger discontinuous outcrop belt in the northern Survey Pass quadrangle. In the Baird Mountains quadrangle,Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Mkl 6330Kayak Shale of Endicott Group and Lisburne Group, Central belt and part of Northern thrust assemblages Mississippian Phyllite or slate, siltstone, sandstone, limestone, and chert exposed in two small areas in the northwestern Baird Mountains quadrangle and in a larger discontinuous outcrop belt in the northern Survey Pass quadrangle. One exposure in the Baird MountainTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Ml 6320Carbonate rocks, Central belt and part of Northern thrust assemblages Mississippian Light- to medium-gray weathering, dark-gray metalimestone and dolostone with locally abundant layers and lenses of black chert, exposed at one locality in the Nanielik antiform, northeastern Baird Mountains quadrangle. The unit contains conodonts of LatTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Mu 6365Metasedimentary rocks, Central belt and part of Northern thrust assemblages Mississippian Quartz conglomerate, quartzite, metasandstone, phyllite, shale, and metalimestone in the Ambler River, Survey Pass, and Wiseman quadrangles. Includes metasiliciclastic and metacarbonate strata in Ambler River and Survey Pass quadrangles, most with few tTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? MzDm 4951Igneous and sedimentary rocks of the Maiyumerak Mountains, Northern thrust assemblages Mesozoic? to Devonian Basalt, limestone, and two belts of m‚lange exposed in the northwesternmost part of the map area. Four northeast-southwest trending belts defined by Karl and others (1989b) and revised in Karl (1992) include, from east to west: matrix supported m‚lange Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? MzPzs 3498Serpentinite, Angayucham Terrane, Serpentinite and Yukon-Koyukuk Basin Mesozoic? to Paleozoic? Greenish-gray, yellowish-green, olive green or greenish-black serpentinite, minor basaltic rocks, harzburgite tectonite, and nephrite jade exposed in the southern Ambler River and adjacent Shungnak quadrangles. In the Cosmos Hills, fault-bounded serpentiTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? OpCc 7740Older carbonate rocks of the Nanielik antiform, Central belt and part of Northern thrust assemblages Middle Ordovician to Proterozoic? Dolostone, metalimestone, marble and subordinate quartzose metasedimentary rocks, carbonate conglomerate, and metabasite exposed in the in the Nanielik antiform (northeastern Baird Mountains and northwestern Ambler River quadrangles), central Survey PassTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? OpCc 7741Older carbonate rocks of the Nanielik antiform, Central belt and part of Northern thrust assemblages, Ordovician rocks only Middle Ordovician to Proterozoic? Dolostone, metalimestone, marble and subordinate quartzose metasedimentary rocks, carbonate conglomerate, and metabasite exposed in the in the Nanielik antiform (northeastern Baird Mountains and northwestern Ambler River quadrangles), central Survey PassTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? pCam 9300Metamorphic rocks of Mt. Angayukaqsraq, Central belt and part of Northern thrust assemblages Proterozoic Amphibolite, metaquartzite, calcareous schist, metapelite, and a few small bodies of metagranite and metagabbro, exposed in the northeastern Baird Mountains quadrangle around Mt. Angayukaqsraq and in the northeastern Ambler River quadrangle. Lithologies Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? pCg 9060Granitic orthogniess Proterozoic Metagranitic rocks of several Proterozoic ages exposed in southern Baird Mountains and western Wiseman quadrangles. In the Schist belt in the Baird Mountains quadrangle, a light-gray, medium- to fine-grained, foliated to gneissic metamorphosed granite sTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzb 7325Black phyllite and siliceous phyllite, Central belt and part of Northern thrust assemblages Paleozoic? Gray to dark-gray carbonaceous phyllite, locally silica rich, exposed in the Central belt in the western Ambler River quadrangle. Equivalent to parts of Pzbs of Mayfield and Tailleur (1978) Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzbq 8602Black quartzite, Schist belt Paleozoic? Black-weathering, fine- to medium-grained black metaquartzite exposed along the contact between units Dsq and DpCsc near the boundary between the Baird Mountains and Ambler River quadrangle. Locally may contain small amounts of mica and show segregatioTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzbs 6331Black metasedimentary rocks, Central belt and part of Northern thrust assemblages Paleozoic Dark-gray to black phyllite and calcareous phyllite with dark-gray to orange-weathering marble and dolostone layers up to 50 m thick are exposed in the northeastern Survey Pass and northwestern Wiseman quadrangles. In the Wiseman quadrangle, the unit isTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzj 6850Metasedimentary rocks of Jesse Mountain, Central belt and part of Northern thrust assemblages Paleozoic Generally fine grained, phyllitic to schistose, gray-weathering meta-argillite, black-weathering metaquartzite, marble, and brown weathering impure marble, exposed in a single area in the eastern Wiseman and western Chandalar quadrangles. Carbonate rocTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzm 6983Marble, Central belt and part of Northern thrust assemblages Paleozoic White to gray (less commonly black), fine to coarsely crystalline, massive to platy marble and subordinate metalimestone and dolostone occurs discontinuously in all quadrangles within the map area. Pzm locally contains abundant disseminated quartz or micTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzp 5560Phyllite, Central belt and part of Northern thrust assemblages Paleozoic? Phyllite, fine-grained schist, and phyllonite of the Central belt that underlie areas of poor exposure in the northeastern Baird Mountains quadrangle, western Ambler River quadrangle, and northwestern Chandalar quadrangle. Locally contains minor lenses Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzpc 5570Carbonate rocks of phyllite belt Paleozoic Fault-bounded blocks of marble, metalimestone, and dolostone that crop out in southwestern Ambler River quadrangle. Carbonate rocks are locally intercalated with black phyllite, black metaquartzite, and metachert, contain megafossils (corals, brachiopodTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? PzpCb 8604Metasedimentary rocks of Bluecloud Mountain, Central belt and part of Northern thrust assemblages Paleozoic to Proterozoic? Light-, medium-, and dark-gray phyllite, dark-gray to black metaquartzite, dark-gray and grayish-brown calcareous phyllite, and reddish-brown-weathering impure marble exposed in fault-bounded lenses along the Schist belt-Central belt contact in the WiseTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? PzpCbs 8601Biotite schist, Ruby terrane Paleozoic to Proterozoic? Quartz-albite-oligoclase-biotite schist with staurolite and andalusite exposed in the southeastern Chandalar quadrangle, adjacent to rocks of the Schist belt. Age of metamorphism not known Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? PzpCcm 8655Metasedimentary and metavolcanic rocks, undivided, Central belt and part of Northern thrust assemblages Paleozoic to Proterozoic Heterogeneous assemblage of interlayered calcareous, mafic, and siliceous rocks exposed in the central Baird Mountains, Ambler River, and Wiseman quadrangles. Includes black quartzite, meta-argillite, and marble; white quartzite; green, buff, and black Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? PzpCem 8611Metamorphic rocks of the Ernie Lake area, Central belt and part of Northern thrust assemblages Paleozoic to Proterozoic Coarse crystalline marble, orange dolomitic marble, quartz-mica schist, metaquartzite, calcareous schist, graphitic metaquartzite, and metabasite exposed in the eastern Survey Pass and western Wiseman quadrangles. Marble is the most common lithology; othTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? PzpCg 9045Granitic rocks Paleozoic to Proterozoic? Pale gray-green, massive to gneissic granitic to dioritic orthogneiss exposed in the Schist belt in the southern Baird Mountains quadrangle. This body was one of several metagranitic rocks from the Schist belt analyzed to evaluate the temperature and prTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? PzpCm 8661Mafic schist, Central belt and part of Northern thrust assemblages Paleozoic? to Proterozoic? Dark green-weathering foliated mafic schist exposed in one area on the boundary between the Ambler River and Survey Pass quadrangles. Composed of green to blue-green amphibole, albite, epidote, quartz, and biotite. Grain size is variable. Epidote occurTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? PzpCqs 8603Quartz-rich metasedimentary rocks, Central belt and part of Northern thrust assemblages Paleozoic to Proterozoic? Relatively homogeneous assemblage dominated by light greenish-gray fine-grained schist, typically accompanied by minor layers of metaconglomerate, marble, and calcareous schist. Exposed in the southern Central belt in the western Survey Pass quadrangle Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? PzpCsr 9325Ruby schist, Ruby terrane Paleozoic to Proterozoic? Biotite-bearing pelitic schist with subordinate metaquartzite, exposed in the southern Chandalar quadrangle. May have crystallized at upper greenschist or amphibolite facies (Dusel-Bacon and others, 1989). Equivalent to schists of the Ruby geanticline, Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzpg 5565Phyllite and graywacke, Phyllite belt Paleozoic? Dark-gray to black phyllite and brown-weathering lithic sandstone, sandstone, and mudstone are exposed along the southern boundary of the schist belt. The unit varies in breadth along strike. In the Wiseman and Chandalar quadrangles, two subunits are rTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzsg 7000Mafic schist, Schist belt Paleozoic Green and greenish-gray, schistose to massive, irregularly-shaped bodies and lenses of metamorphosed mafic rocks in units Dsq and DpCsc large enough to show at the scale of the map occur in the Survey Pass and Chandalar quadrangles. Relict pillow structuTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzsm 6980Marble of the Schist belt Paleozoic Metacarbonate rocks form an elongate belt in the central Ambler River quadrangle and are the only mappable occurrence of massive carbonate strata in the Schist belt. The unit surrounds the Redstone pluton (Sheet 2) and includes a variety of rock types (JTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzw 6927Metasedimentary rocks, Central belt and part of Northern thrust assemblages Paleozoic Weakly to moderately metamorphosed metasandstone, meta-argillite, phyllite, conglomerate, and rare marble exposed in two belts that straddle the northern part of the Wiseman/Chandalar quadangle boundary. The northern belt is composed of metasandstone anTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Pzw_5726927Metasedimentary rocks, Central belt and part of Northern thrust assemblages Paleozoic Weakly to moderately metamorphosed metasandstone, meta-argillite, phyllite, conglomerate, and rare marble exposed in two belts that straddle the northern part of the Wiseman/Chandalar quadangle boundary. The northern belt is composed of metasandstone anTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Qs 100 Surficial sedimentary deposits, undivided Quaternary Frost-rived rubble on slopes and broad low ridges; glacially deposited sand, gravel, and boulders; fluvial gravel and sand; terrace deposits; wetlands Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? QTb 350 Basalt Quaternary? or Tertiary? Flat-lying, vesicular olivine basalt flows exposed in the southeastern part of the Chandalar quadrangle. Thought to be about 300 meters thick (Brosg‚ and Reiser, 1964) Till, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? SCvs 6720Volcanic and sedimentary rocks, Doonerak antiform Silurian to Cambrian Volcanic rocks, volcaniclastic rocks, and clastic sedimentary rocks exposed in the core of the Doonerak antiform, northeastern Wiseman quadrangle. The unit can be divided into at least two lithologic sequences, one dominated by volcanic rocks, the otherTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? Spl 6686Black phyllite and metalimestone, Central belt and part of Northern thrust assemblages Silurian Black siliceous phyllite and metalimestone, metasandstone, metasiltstone, phyllite, and graphitic calcareous schist in the eastern Ambler River and western Survey Pass quadrangles. Conodonts and graptolites indicate Silurian ages for these strata in theTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-? TrCs 5004Sedimentary rocks, Doonerak antiform Triassic to Carboniferous Quartzite, phyllite, siltstone, conglomerate, shale, sandstone, limestone, argillaceous limestone, dolomitic limestone, and cherty dolostone. The unit occurs in the Mount Doonerak area in northeastern Wiseman and northwestern Chandalar quadrangles, wherTill, A.B., Dumoulin, J.A., Harris, A.G., Moore, T.E., Bleick, Heather, and Siwiec, Benjamin, in press, Bedrock geologic map of the southern Brooks Range, Alaska, and accompanying conodont data: U.S. Geological Survey Scientific Investigations Map SIM-?