Qs
Surficial deposits, undivided
Quaternary
Frost-rived rubble on slopes and broad low ridges; glacial moraine; glacially deposited sand, gravel, and boulders; fluvial gravel and sand; marine and fluvial terrace deposits; wetlands
Till, A.B., Dumoulin, J.A., Werdon, M.B., and Bleick, H.A., 2009, Bedrock geologic map of the Seward Peninsula, Alaska:  U.S. Geological Survey Open-File Report 2009-1254, text, tables, and 2 sheets, scale 1:500,000.
Qlj
Lost Jim Basalt
Quaternary, Holocene
A single basaltic lava flow and associated vent deposits, undisrupted by frost brecciation, located in central Bendeleben quadrangle (fig. 2). The dark gray-black vesicular olivine basalt in eastern part of the unit exhibits pahoehoe flow features and la
QTv
Weathered volcanic rocks, undivided
Quaternay and Tertiary
Basalt lava flows, vent deposits, maar volcanoes and associated pyroclastic rocks exposed in northern, central, eastern, and to a minor extent, southern Seward Peninsula (fig. 2).
Less weathered rocks are slightly to strongly fragmented by frost riving a
TKs
Carbonate-rich conglomerate and sandstone; mudstone, siltstone and coal, Kugruk Fault Zone
Tertiary and Cretaceous
Two separate sedimentary sequences, of broadly different age: tan to light-gray siltstone, sandstone, and pebbly sandstone, and light-gray-weathering conglomerate composed mostly of marble, metalimestone, and dolostone clasts, probably of mid-Cretaceous
TKv
Felsic volcanic rocks
Rubble crop of volcanic rocks in northeastern part of the map area, in Bendeleben D-1 quadrangle (fig. 2).  Unit consists of two varieties of volcanic rock, both moderately to strongly limonite stained.  One is a volcanic flow or tuff that contains up to
Kv
Andesite and basalt flows and volcaniclastic rocks
Early Cretaceous
Andesite and basalt flows interbedded with volcaniclastic rocks and volcanic greywacke; exposed along eastern boundary of the map in Candle quadrangle (fig. 2).  Calcareous tuffs in upper part of the unit contain abundant shelly material, including abund
Kds
Dikes and stocks
Cretaceous
Dikes and rare stocks of a variety of compositions and ages mapped extensively in the York, Kigluaik, and Bendeleben Mountains, and near the Darby Mountains, but also present in the Nome Complex.  Some, but not all, are shown on the map as small pink lin
Kgu
Granitic rocks, undifferentiated
Granitic dikes, sills and small plugs at widely scattered localities (fig. 2).  Most commonly these bodies occur within exposures of high-grade metamorphic rocks (unit |<h), but unit is also present in the Nome Complex and on islands off the south and we
Kg
Kigluaik granite
Fine- to medium-grained felsic rocks of the upper part of the Kigluaik pluton (fig. 2), including leucocratic biotite granite and granodiorite (Amato and Miller, 2004).  Unit is more extensively exposed than the mafic root, the Kigluaik diorite (unit Kdi
Ktg
Tin-bearing granitic stocks
Late Cretaceous
Stocks of biotite granite exposed in outcrop, rubble, and float in northwestern Seward Peninsula.  Includes stocks at Cape Mountain, Brooks Mountain, Black Mountain, Ear Mountain, and the Oonatut Granite Complex (fig. 2).  The belt also includes bodies n
Kbk
Bendeleben and Kuzitrin plutons
Monzogranite and granodiorite; outcrop, talus, rubble, and some cirque headwall exposures in eastern Bendeleben Mountains in Bendeleben A-2, A-3, B-2 and B-3 quadrangles, and small rubble fields north of the range in Bendeleben C-3 quadrangle (fig. 2).
Kwc
Windy Creek pluton
Talus and frost-riven rubble at north end of the Darby Mountains in Bendeleben A-1 and A-2 quadrangles.  Rock type is quartz monzonite that is locally cut by biotite granodiorite dikes (fig. 2).  Blocks or roof pendants of metamorphic rocks are locally c
Kgr
Granite and granodiorite
Equigranular biotite-hornblende quartz monzonite exposed along eastern boundary of map area in Candle quadrangle, at Granite Mountain and in the "J" shaped Quartz Creek pluton (fig. 2).  Quartz monzonite at the core of the zoned Granite Mountain body gra
Kp
Pargon pluton
Fine grained equigranular, fine to medium grained seriate granodiorite, monzodiorite, and locally monzogranite exposed in the western Bendeleben Mountains along the upper reaches of the Pargon River (fig. 2).  Granodiorite and quartz monzonite are the do
Kku
Kugruk pluton
Frost-riven rubble in northeast corner of Bendeleben C-2 quadrangle (fig. 2).  Quartz monzonite to quartz monzodiorite.  Green porphyritic rocks of approximately dioritic composition at the eastern margin of the pluton may be a border phase.  Aeromagneti
Kd
Darby pluton
Elongate monzogranite, locally granodiorite pluton 80 km long and 3 to 8 km wide that extends along crest of the Darby Mountains in southeast part of the peninsula (fig. 2).  Outcrops are common in northern part of the pluton; frost-riven rubble predomin
Ks
Stocks, undifferentiated
Frost-riven outcrops, rubble fields, and float of felsic intrusive rocks at four localities align along a roughly north-south trend in Bendeleben C-3 and D-3 quadrangles (fig. 2).  The northernmost, Crossfox Butte stock, is monzogranite to quartz monzoni
Kkms
Monzonite-syenite
Monzonite-syenite phase of the Kachauik pluton; exposed as frost-riven rubble, talus and outcrop in Solomon B-2, C-2 and D-2 quadrangles (fig. 2).  This phase is the most voluminous phase of the pluton, and is cut by aplite, quartz latite porphyry, lampr
Kkg
Granodiorite
Granodiorite-quartz monzonite phase of the Kachauik pluton, exposed in frost-riven rubble, talus and outcrop in Solomon C-2 and D-2 quadrangles (fig. 2).  Unit is cut by aplite, quartz latite porphyry, lamprophyre and alkaline dikes (Miller and others, 1
Kkd
Diorite
Hybrid diorite of the Kachauik pluton; exposed in Solomon B-2 quadrangle (fig. 2).  Unit is coarse grained and characterized by abundant biotite and may be a border phase of the monzonite-syenite (unit Kkms) of the Kachauik pluton (Miller and others, 197
Kdi
Kigluaik diorite
Fine- to medium-grained potassic mafic rocks of the lower part of the Kigluaik pluton, including biotite hornblende diorite, quartz diorite, granodiorite, tonalite, and gabbro, exposed in the western Kigluaik Mountains (fig. 2; Amato and others, 1994; Am
Kdc
Dry Canyon stock
Frost-riven rubble of nepheline syenite on west side of Darby Mountains in Solomon D-2 quadrangle (fig. 2).  Unit has a trachytoid fabric and yielded a K-Ar hornblende age of 108±3 Ma (Miller, 1972)
Ksy
Syenite, monzonite, and nepheline syenite
Syenite, monzonite, and subordinate quartz monzonite, monzodiorite, quartz syenite, nepheline syenite and related mafic alkaline rocks of Patton and others (2005); exposed along eastern boundary of map area, in Candle quadrangle (fig. 2).  Part of the "w
Kkgm
Gneissic monzonite
Gneissic monzonite of the Kachauik pluton; exposed in Solomon C-2 quadrangle (fig. 2).  Unit has a gneissic to trachytoid texture, and may be a border phase of the monzonite-syenite (unit Kkms) of the Kachauik pluton (Miller and others, 1972)
Jt
Spruce Creek tonalite, Kugruk Fault Zone
Jurassic
Tan-weathering, recessive, quartz-poor, plagioclase-rich intrusive rock.  Rubble along middle to upper portions of Spruce Creek, in the headwaters of the Kugruk River in Bendeleben B-2 and B-3 quadrangles, is 50 to 70 percent plagioclase, 5 percent hornb
MzPzm
Metamorphosed mafic rocks and serpentinite, Kugruk Fault Zone
Mesozoic and Paleozoic?
Tectonic assemblage of metagabbro, metabasalt, amphibolite, serpentinite, and minor chert, exposed in rubble fields and poor outcrops along the trend of the Kugruk Fault Zone.  Mafic rocks include minor unmetamorphosed (but altered) rocks, rocks with rel
Pzl
Limestone, York terrane
Paleozoic
Intensely deformed limestone that has yielded no fossils but is presumed to be of Paleozoic age (Sainsbury, 1972), exposed in several small outcrops in central Teller quadrangle, northeast of the York Mountains.  Equivalent to western part of unit "Pzl"
Pzp
Phyllite and argillite, Grantley Harbor Fault Zone
Phyllite, argillite, and lesser metasiltstone and fine-grained metacarbonate rocks exposed south and north of Grantley Harbor in central Teller quadrangle.  Outcrops consist of brownish-orange- to black-weathering, silvery-gray to black, locally carbonac
Pznp
Metagabbro and metasediments, Nome Complex
Paleozoic?
Massive tors and rubble piles of metagabbro and poorly exposed metasedimentary rocks on west side of the Kigluaik Mountains.  Metagabbro bodies form flat-topped hills generally less than a kilometer across; one body exposed along sea cliffs is 9 km long.
Pzm
Marble, undivided, Nome Complex
Generally light-gray-weathering, white to medium-gray, medium to coarsely crystalline marble that forms rubble-covered hills and small outcrops that are widely but sparsely distributed through the map area.  Marble is dominantly pure, but locally contain
Pzmm
Marble of the Moon Mountains, Nome Complex
Pale-gray- to white-weathering, coarsely crystalline calcite marble exposed only in western Nome quadrangle, in an area informally called the Moon Mountains (sh. 2) due to lack of vegetation.  The marble has a layered appearance due to variations in grai
Pzd
Dolostone, undivided, Nome Complex
Generally light-colored, fine-grained, featureless dolostone that forms rubble-covered hills sparsely distributed through the map area.  This unit likely includes rocks of several ages.  Conodont faunas, obtained at seven localities, are mostly long rang
Ml
Limestone, dolomitic limestone, and marble, York terrane
Mississippian
Intensely deformed and recrystallized medium-dark-gray carbonate rocks, locally cherty and intercalated with subordinate fine-grained siliciclastic strata, exposed on westernmost tip of Seward Peninsula (Teller quadrangle; Sainsbury, 1972).  Unit has bee
Sd
Dolostone, Nome Complex
Silurian
Light-gray- to tan-weathering, light- to dark-gray, fine-grained, ferroan dolostone that forms two small rubble-covered hills, one in southeastern Bendeleben quadrangle and the other in southeastern Solomon quadrangle.  At the northern locality, the main
DSl
Devonian and (or) Silurian
Light-gray-weathering, medium-dark-gray limestone exposed in a small, fault-bounded area in central Teller quadrangle.  Lithofacies include cherty lime mudstone, peloidal wackestone, and lesser coralline packstone.  Lower beds produced relatively long-ra
PzZg
Gneiss and orthogneiss, High-grade metamorphic and associated igneous rocks
Paleozoic? and Proterozoic?
Light brownish gray, light orange to gray biotite-plagioclase-quartz gneiss and granitic orthogneiss and minor metasedimentary rocks exposed in rubble crop north of the Oonatut Granite Complex, northwest Bendeleben quadrangle (Hudson, 1979).  The fabric
Dg
Granitic orthogneiss, Nome Complex
Devonian
Fine-grained, very light gray to orange-weathering, well-foliated, white to light tan schist of granitic to tonalitic composition that forms the rounded, frost-riven slopes of Kiwalik Mountain and one small body in northern Darby Mountains.  Commonly for
Df
Felsic schist, Nome Complex
Light-orange to light-green-weathering fine- to coarse-grained quartz-feldspar-white mica schist.  Crops out on the southwest flank of Kiwalik Mountain as platey rubble-crop of millimeter-scale laminated, very fine grained schist.  Rarely, accessory blac
Ddm
Dolostone, metalimestone, and marble, Nome Complex
Medium- to dark-gray-weathering, dark-gray to black dolostone, metalimestone and marble, with minor associated chert, that typically weathers to fist-sized rubble but forms outcrops along river banks or sea cliffs.  Ddm is widely but sparsely distributed
Dcs
Pelitic, calcareous, and graphitic schist, Nome Complex
Pelitic, calcareous, and graphitic lithologies interlayered on a scale of centimeters to meters, exposed in central Nome and Solomon quadrangles.  Interlayering is gradational and intimate.  The unit is composed predominantly of pale brown and gray weakl
Ds
Pelitic schist, Nome Complex
Devonian?
Tors of resistant, well-foliated quartz-rich schist.  Pelitic rocks are the dominant lithology; calcareous schist is a minor component.  Outcrop appearance of the pelitic schist is diagnostic of the unit, and shows 1- to 2-cm-thick bands of granular inte
DObm
Black metalimestone and marble, Nome Complex
Devonian to Ordovician
Dark-gray to black metalimestone and marble and subordinate dolostone exposed on sea cliffs on Kotzebue Sound.  Rocks weather gray to yellowish-brown, commonly have fissile partings, and are well layered.  Layers range from 2 to 50 cm thick, with rhythmi
DCbm
Black marble, Nome Complex
Devonian to Cambrian
Dark gray to black marble and subordinate fissile impure marble, calcareous schist, and mafic schist that crops out in eastern Solomon and western Norton Bay quadrangles.  Unit is best exposed in sea cliffs along Norton Bay and forms rubble covered hills
DCks
Calcareous schist of Kwiniuk Mountain, Nome Complex
Dark-brownish-gray, rust-spotted, well-foliated, medium-grained schist composed predominantly of quartz, calcite, white mica, chlorite, plagioclase, and graphite.  Locally shows millimeter-scale dark/light layering.  Rusted spots (weathered iron carbonat
DOx
Mixed marble, graphitic metasiliceous rock, and schist, Nome Complex
Interlayered pure and impure marble, graphitic metasiliceous rock, pelitic schist, calc-schist, and mafic schist.  Gray- and orange-weathering marble and dark gray-black-weathering graphitic metasiliceous rock are the most common lithologies in the unit,
DOx, overlay
Interlayered pure and impure marble, graphitic metasiliceous rock, pelitic schist, calc-schist, and mafic schist.  Gray and orange weathering marble and dark gray-black weathering graphitic metasiliceous rock are the most common lithologies in the unit,
Ol
Ordovician
Mainly massive to thick-bedded, light-brownish-gray to medium-gray, fine-grained limestone with local chert nodules and lesser interbeds of argillaceous limestone and shale, widely exposed in and adjacent to the York Mountains in western and central Tell
SOdl
Dark limestone, York terrane
Silurian and Upper Ordovician
Medium- to thick-bedded, light-brown to dark-gray limestone, dolomitic limestone, and dolostone, locally cherty, commonly very fossiliferous, exposed in a fault-bounded area in northeastern York Mountains (Teller quadrangle; "section on Don River" of Sai
Ols
Limestone and shale, York terrane
Thin- to medium-bedded, pale-orange- to pale-yellow-brown-weathering, medium-gray to dark-gray limestone, dolomitic limestone, and dolostone with local shale and chert nodules.  Ols forms subdued slopes within, north of, and east of the York Mountains; t
Od
Light-gray- to pink- to tan-weathering, gray to tan dolostone that forms small areas of rubble crop in tundra and local cliffs along river banks.  Unit is best exposed along several rivers in northeastern Bendeleben quadrangle, but also crops out at isol
SOul
Limestone and dolostone, undifferentiated, York terrane
Silurian and Ordovician
Carbonate rocks equivalent to unit Ols and (or) unit SOdl, but less well studied than those units; exposed in three small fault-bounded areas in central part of the Teller quadrangle.  The western and central exposures are limestone with corals of Late O
Oal
Argillaceous limestone and limestone, York terrane
Thin-bedded, argillaceous, silty and (or) dolomitic limestone, lesser massive micritic limestone, and local chert; rocks are light gray to medium gray and weather light gray to orange to tan.  The unit is widely exposed in and adjacent to the York Mounta
OZl
Limestone and dolomitic limestone, York terrane
Ordovician through Proterozoic
Light-gray- to grayish-orange-weathering, medium-light-gray to medium-dark-gray limestone and dolomitic limestone that occurs widely in western, central, and northern parts of the Teller quadrangle.  The unit forms low outcrops and extensive areas of rub
OZt
Sandstone, siltstone, and limestone, York terrane
Gray- to orange-weathering, gray to brown, locally calcareous sandstone to siltstone, interbedded with gray to black mudstone and local limestone, exposed in western Teller quadrangle.  Beds are typically =5 cm thick (20 cm maximum).  Outcrop features, w
OZp
Phyllite, York terrane
Fine-grained, mainly pelitic and (or) calcareous phyllite exposed in west-central Teller quadrangle.  Unit crops out on creeks, weathers gray to grayish-brown, and is layered and locally finely laminated.  The phyllitic foliation surface is crenulated.
Ocs
Casadepaga Schist, Nome Complex
Light-green, silvery green and greenish-brown mafic, feldspathic, and calcareous schist.  Typically occurs as frost-riven slabs and flakes that underlie rounded hills and dark-greenish-black tors and rubble piles several meters across.  Tors of metabasit
Oim
Impure chlorite marble, Nome Complex
Buff- to orange-weathering chlorite-, white mica-, and albite-bearing calcite marble that underlies rounded hills. Rare outcrops show well-foliated impure marble to calcareous schist.  Impurities are most commonly chlorite and albite.  Lenses (up to a me
Cd
Cambrian
Gray- to orange-weathering, light-gray or medium-gray to pinkish-orange dolostone that forms hilltop rubble patches and subcrop on several small knobs in the northwestern Solomon quadrangle.  The dolostone is non-ferroan to moderately ferroan and locally
PzZt
Metasiltstone and phyllite, Grantley Harbor Fault Zone
Paleozoic and Proterozoic?
Metasiltstone, metasandstone, and phyllite that form a small exposure south of Grantley Harbor in central Teller quadrangle.  The unit consists of intercalated grayish-green metasiltstone to medium-grained metasandstone, in layers 1 cm to 1 m thick, gray
PzZl
Metalimestone, Grantley Harbor Fault Zone
Thinly layered to laminated, orange-and gray-weathering, color-banded, white to dark-gray metalimestone exposed in a small area south of Grantley Harbor in south-central Teller quadrangle.  Layers range from a few millimeters to 6 cm thick and reflect di
PzZh
High-grade metasedimentary and metaigneous rocks, High-grade metamorphic and associated igneous rocks
Paleozoic and Proterozoic
Brown, light-brown, reddish-brown, black, and gray-weathering schist and gneiss exposed in the Kigluaik, Bendeleben, and Darby Mountains.  Highest grade metamorphic assemblages are upper amphibolite to granulite grade; assemblages in all three ranges rec
PzZm
Marble, High-grade metamorphic and associated igneous rocks
Paleozoic to Proterozoic?
Light-gray weathering, coarse-grained pure and impure marble interlayered with unit PzZh.  Commonly massive, though locally meter-thick layers are separated by thin (centimeter-scale) layers of fine-grained impurities.  Thin sections show equilibrium met
Pzgb
Metagabbro, York terrane
Dark-green to black-weathering massive bodies of metagabbro exposed in rubble crop and small blocky cliffs associated with units OZt, OZp and OZl (Sainsbury, 1969b).  Throughout the unit, igneous textures are retained in thin section.  In central Teller
Light-brownish-gray, light-orange to gray biotite-plagioclase-quartz gneiss and granitic orthogneiss and minor metasedimentary rocks exposed in rubble crop north of the Oonatut Granite Complex, northwest Bendeleben quadrangle (Hudson, 1979). Fabric in th
Zo
Orthogneiss, High-grade metamorphic and associated igneous rocks
Proterozoic
Pale-gray-, tan- and orangish-tan-weathering outcrops and rubble fields of foliated and unfoliated metagranitic rocks that form a large, tabular, concordant body within high-grade rocks of the Kigluaik Mountains.  Called the "Thompson Creek orthogneiss"
Zv
Metavolcanic rocks, High-grade metamorphic and associated igneous rocks
Foliated lens- to sill-shaped bodies in western Bendeleben Mountains exposed in outcrop and rubble fields.  Unit is up to 50 m thick.  Very fine grain size and variation in abundance and relative proportion of biotite and hornblende suggest a volcanic pr
Zn
Metagranitic rocks, Nome Complex
Late Proterozoic
Pale-gray to pale-greenish-tan, locally green-weathering rubble crop and outcrop of small granitic, granodioritic, and tonalitic orthogneiss bodies.  Weakly-foliated to well-foliated, fine- to coarse-grained, with foliation defined by weak to strong alig