Qu
Unconsolidated and poorly consolidated sediments, undivided
Quaternary
Surficial material deposited by water, wind, freeze-thaw cycles, and glaciers
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.
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,
Tb
Basalt flows and rare cinder cones
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 (Cole
Tv
Volcanic rocks
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 geanti
Tg
Granitic rocks
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 li
TKs
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 bee
Kkyu
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 a
Kku
Sedimentary rocks of the Kandik basin, undivided
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 hav
Kg
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 and
KJu
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 (Brosgé and Reiser, 1969; Brabb, 1970). Bivalves of Jurassic or Cretaceous age reported from one exposure in the Coleen qu
Mzmv
Fine-graned sedimentary rocks and tuff
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
KJg
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 been
JMsu
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,
JMpu
Younger strata of the Porcupine River sequence of Brosge' and Reiser (1969), undivided
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 flows
KJmu
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 (1987
TrPs
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). Conod
TrPgt
Glenn 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 expos
PCta
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 rock
JDat
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 ig
MzPza
Low-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
TrPzd
Metasedimentary 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, 199
Pzvu
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 (Brosgé and Reiser, 2000).  Devonian (?) plants and spores, Mississippian (?) Radiolaria, and Permian conodonts have been recovere
Pzcm
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 is
Pzum
Ultramafic rocks
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 se
DZs
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 structure
Pzqs
Sedimentary and igneous rocks
Permian, Carboniferous, and Devonian
Quartz-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 mudstone
KDe
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)
Mbu
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 (Brosgé an
DCpu
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
DSc
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 Yuk
Cg
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 ra
CPt
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 u
PzZl
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,
PzZw
Sedimentary and igneous rocks corresponding to the older parts of the Fairbanks-White Mountains area sequence of Weber and others (1992)
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; muds
PzZs
Sedimentary and igneous rocks corresponding to older parts of the Schwatka-Rampart area sequence of Webber and others (1992)
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 ro
PzpCy
Metamorphic 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 lo
PzpCh
Metasedimentary 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 im
PzpCm
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
PzpCb
Metasedimentary and metaigneous rocks of the southern Brooks Range and Ruby geanticline
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 (