btu
Bedrock unknown
Unknown but likely Precambrian or older
type unknown; relations uncertain
OP002
Ophir
pCu
bu  pc /TrMc
None
Uncertain
Map shows questionable identification of unit.
Metamorphic
bu
Qac
Alluvium
Quaternary
Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.  Chiefly silt and very fine sand.  Terrace deposits largely fluival but in part lacustrine; slope deposits primarily eolian and colluvial.
The "Palisades" along the Yukon have yielded Pleistocene vertebrate fauna including mammoth and bison remains.
MZ002
Melozitna
Unconsolidated
Qal
Qu
Undifferientiated lowland silt, sand, muck, and gravel
Qs
Qf
Floodplain deposits
KT002
Kateel River
Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits
Chiefly silt and very fine sand.  Includes extensive loess deposits
MD002
Medfra
Qcal
Colluvium and alluvium, undifferentiated
Silt and sand mantling broad, flat valleys
TN002
Tanana
Silt, sand, and gravel of stream beds, flood plains, and terraces
RB003
Ruby
Q
Surficial materials, undivided
Includes stream alluvium, colluvial deposits, terrace gravel, eolian deposits, and glacial deposits
TN003
Qc
Fluvial, colluvial, and eolian terrace and slope deposits, undivided
Holocene and Pleistocene
Silt and very fine sand
UL002
Unalakleet
Unconsolidated deposits
RB004
Surficial deposits
Alluvium, colluvium, and loess
RB002
Undifferentiated glacial drift, eolian and alluvial deposits
BT002
Bettles
Qae
Undifferentiated alluvium, eolian terrace and slope deposits
Pleistocene and Recent
Undifferentiated alluvium and eolian terrace and slope deposits of silt and very fine sand
HU002
Hughes
Undifferentiated alluvial and eolian deposits
Undifferentiated alluvial and eolian deposits, chiefly silt and fine sand.  Includes glacial outwash and fan gravels locally.
SH002
Shungnak
Qua
Undifferentiated alluvial, colluvial, and eolian terrace and slope deposits.
SP003
Survey Pass
BT003
AR003
Ambler River
Alluvial, colluvial, glacial, and windblown deposits, undivided
Glacial deposits, alluvuim, colluvium, and landslides.
WI003
Wiseman
Sedimentary
Undifferentiated alluvial, colluvial and eolian terrace and slope deposits
RB009
Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided
Chiefly  silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels
SE004
Selawik
Alluvial, colluvial, glacial, and windblown  terrace and slope deposits, undivided
Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels
UL003
wi004
Chiefly silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.
OP005
HU003
MD004
TN008
RB005
NL004
Nulato
Quaternary, Holocene and Pleistocene
Chiefly  silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravel
KT004
Qa
Qfy
Younger flood-plain deposits
Light-gray micaceous silt.  Sand and gravel along streams that drain bendrock uplands.  Characterized physiographically by badrs, oxbows, meander scars, abandoned channels, and other evidence of recent flood-plain building.
Silt, sand and gravel of streambeds, flood plains and terraces
NL002
Light-gray micaceous silt.  Sand and gravel along streams that drain bedrock uplands
Recent alluvium
Holocene
Sandy gravel and sandy silt, forms flood plain of modern rivers and streams.
Qags
Older alluvium
Coarse, silty sand and fine gravel; generally forms terrace sloping up and away from floodplains of streams and rivers
Chiefly light-gray micaeous silt along Yukon and Koyukuk rivers.  Silt, sand and gravel along streams that drain bedrock uplands.  Locally include some terrace and fan deposits along narrow tributary valleys.  Mapped from aerial photographs.
NL003
Flood-plain deposits
Silt, sand, and gravel along floodplains of stream valleys
Flood-plain deposits.  Gravel, sand, and silt along flood-plains of major stream valleys
CA002
Candle
Qfp
Flood Plain deposits
Pleistocene and recent
Flood Plain deposits of gravel, sand, and silt along flood plains of major drainages
Silt, sand, and gravel along flood plains of major drainages.  Locally includes some fan and terrace deposits along narrow tributary valleys
Qft
SE002
Alluvial deposits
Unconsolidated gravel, sand, silt, and clay
BM002
Baird Mountains
Floodplain and tidal flats deposits.
Floodplain and tidal flats deposits.  Gravel, sand, silt, and peat
Floodplain and tidal flats deposits
Floodplain and tidal flats deposits.  Gravel, sand, silt, and peat.
Floodplain and tidal flat deposits.
Floodplain and tidal flat deposits.  Gravel, sand, silt, and peat.
BM003
Floodplain and tidal flats deposits. Gravel, sand, silt, and peat
Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt.
MZ004
Gravel, sand, silt, and peat. Floodplain deposits in Koyukuk Flats and along Yukon River composed mainly of light gray micaceous silt
Qaf
Alluvial fan deposits
Gravel, silt, and sand, commonly occur at mouth of small side canyons.  Includes some colluvial deposits.
Colluvium
Colluvium, undifferentiated
Predominantly silt, with some sand and gravel.
Qta
Talus
Angular boulder rubble in cirque.
Qh
High-level eolian and colluvial deposits
Pleistocene
Windblown and reworked windblown deposits of silt and very fine sand
Qrs
Recent slide and slump deposits
Very fresh, unmodified slumps and earthflows (Occurred about 1940).
Qls
Older landslide deposits
Slumps and earth and rock slides
ls
Landslide deposits
Quaternary?
Not described
Qt
Terrace alluvium
Terrace deposits
Qhs
High terrace and slope deposits
Light-gray and grayish-orange micaceous silt.  Subordinate lenses of sand and peat.
Qbg
Low-level bench gravel of Minook Creek
Gravel and sand on bench along lower parts of Minook and Hunter Creeks
Qtr
Gravel, silt, and sand near mouth of Fleshlanana Creek
High-terraces and slope deposits
Light-gray and grayish-orange micaeous silt deposits.  Subordinate lenses of sand and peat.  Deposits form a broad terrace 10 to 100 m above the floodplain of the Koyukuk Flats and extend as much as 250 m up the slopes of the bedrocks hills surrounding t
Terraced alluvial silt deposits with minor peat and gravel
Terrace and slope deposits
NR002
Norton Bay
Chiefly  silt and very fine sand including thick deposits of micaeous silt in the Koyukuk Flats and Nowitna and Innoko Lowlands.  Local deposits of alluvial fan and glacial outwash gravels.
CA003
Qfo
Older flood-plain deposits
Chiefly light-gray and grayish-orange micaeous silt.  Locally include peat, reworked eolian sand and gravel.  Deposits at or near river level but youthful flood-plain features are much modified or absent.  Contact with Qfy locally gradational and poorly
Older floodplain deposits
Chiefly light-gray and grayish-orange micaceous silt.  Locally includes peat, reworked eolian sand, and gravel
Silt, sand, and gravel
Largely silt and sand but probably includes abundant gravel along Tonzona River.
Cheifly light-gray and grayish-orange micaeous silt.  Subordinate lenses of sand and peat, reworked eolian sand, and gravel.  Deposits are at or near river level but youthful floodplain features such as oxbow lakes, meander scrolls, and abandoned channel
Flood-plain and estuarine deposits
Qes
Flood-plain and tidal flats deposits
NR003
Qna
Nogahabara sand dunes -- active dunes
Active dunes.  Circular body, nearly 5 mi in diameter.  Entriely sand, free of vegetation cover.
Qd
Sand
Eolian sand deposits of the Kobuk Sand Dunes
Qsa
Actively drifting and recently stabilized dune fields
Fine- to coarse-grained sand
Great Kobuk and Little Kobuk Sand Dunes in the southwestern Ambler River and southeastern Baird Mountains quadrangles, and Nogahabara Sand Dunes in the Kateel River quadrangle.   The Great Kobuk and Little Kobuk dune fields covering  24 square miles (65
Ambler river
Qms
Modified eolian sand deposits
Dark-yellowish-orange and light-gray, fine- to medium-grained eolian sand.  Forms briad sheetlike dune field mantling older floodplain (Qfo) and alluvial terrace (Qac) deposits of the Dulbi Flats.  Deposits have a strong northeast-southwest trend.
Qns
Nogahabara sand dunes -- stabilized dunes
Scattered circular and elliptical bodies of eolian sand.
Dark-yellowish-orange and light-gray, fine- to medium-grained eolian sand.  Forms broad sheet-like dune field mantling alluvial silt deposits of the Koyukuk flats and all but tops of bedrock hills in vicinity of Roundabout Mountain.
Sheetlike dune fields of tan fine- to medium-grained eolian sand, locally overlain by peat and loess
Qess
Sand and silt
Well-sorted sand, commonly in subdued dune forms
Chiefly sand deposits
Modified and dissected deposits of wind-blown and water-laid sand with subordinate amounts of silt
Qws
Chiefly wind-blown and water-laid silt
Chiefly wind-blown and water-laid silt.  Locally includes glacial outwash.
Eolian deposits
Eolian and water-laid sand sheets and active and stabilized sand dunes.
Eolian and water-laid sand sheets and sand dunes.
Eolian and water-laid sand sheets and dunes.
Eolian and water-laid sand and silt
Eolian and water-laid sand and silt sheets and stabilized dune fields
Modified and partly dissected sheets of mixed wind-blown and water-laid deposits bordering the south edge of the Brooks Range
SH004
Sand and coarse silt.
Ql
Loess
Well-sorted silt
Qfl
Qg
Glacial drift
Unsorted bouldery till and isolated moraines; may include some younger solifluction deposits near valley sides.
Qm
Unsorted bouldery till
Qdw
Glacial drfit
Quaternary, probable Wisconsin
Chiefly till and outwash deposits of Walker Lake Glaciation
Qda
Chiefly till and outwash deposits of Ambler Glaciation.  Locally includes outwash of Walker Lake Glaciation.
Glacial deposits
Undifferentiated glacial deposits.
Locally mapped glacial deposits
TN007
QTgl
Glacial and glaciolacustrine deposits.
Includes unsorted to poorly sorted till, outwash sand and gravel, alluvium, and eolian deposits.  Along the southern edge of the Brooks Range, unit is characterized by little-modified middle and late Pleistocene drift including prominent morainal ridges
Glacial and glaciolacustrine deposits
Pleistocene and Pliocene?
Qt4
Till, Cirque glaciation
Unsorted boulder to clay-size  particles.  Moraine forms locally present, restricted to cirques
Qnd
Till, undifferentiated
Unsorted boulder to clay-size particles, no clear morainic forms.
Qwu
Qyg
Younger Glacial drift
Younger Glacial drift of till and outwash gravel and sand
Qt3
Till
Unsorted boulder to clay-size particles, includes long low lateral moraine on Halu Creek
Qwr
Qt2
Unsorted boulder to clay-size particles, lowest moraine on Halu Creek
Qw2
Qt1
Unsorted boulder to clay-size particles, farthest down valley moraine on lower Halu Creek.
Qw1
Qb
Rock-defended terraces on Minook Creek
Erosional benches along east side Minook Creek
Qrd
Qat
Altiplanation terrace
Flat, even surface, formed on bedrock hilltops generally above 600 m
Qga
Undifferentiated older glacial drift and alluvium
Undifferentiated older glacial drift and alluvium of glacial till and outwash, silt, colluvium, and loess
Undifferentiated older glacial drfit, alluvium, and eolian deposits
Quaternary, Illinoian
Chiefly highly modified till and outwash gravels mantled by wind-blown and water-laid silt and fine sand.
Qog
QTg
Gravel deposits on Jones Creek
Quaternary-Tertiary
Moderately dipping gravel exposed on Jones Creek near Nixon Fork fault, approximately 25 m thick
High-level gravel
late Tertiary or early Quaternary
Well packed gravel, caps hills in vicinity of Rampart
QTgr
Quartz gravel deposits
Quaternary/Tertiary
High-level deposits of quartz pebble gravel; overlies basalt flows of unit Tb.
Quaternary or Tertiary
Qya
Younger alkalic basalt cones and flows
More than 40 alkali basalt, basanite, and hawaiite cones, short flows, and maar craters
Igneous
Qyt
Younger tholeiitic basalt cones and flows
Holocene (?) and Pleistocene
Black glassy olivine tholeiite basalt flows of well-preserved pahoehoe structure including ropy flow surfaces and lava tubes
Whole-rock K/Ar age of 0.19+0.02 Ma
QTb
Basalt
early Quaternary or late Tertiary
Nearly horizontal flows of vesicular olivine basalt.  Flows extruded over terrain of moderate relief, ranging in elevation from 175 to over 1,600 feet.
Older basalt flows
Pleistocene and Pliocene
Abundant vesicular tholeiitic and alkali olivine baslt flows which form a broad shield volcano.  Columnar jointed.  Tholeiitic basalt has diktytaxitic texture
4 whole-rock K/Ar ages of 3.25+0.11 Ma, 2.8+0.1 Ma, 1.99+0.06 Ma, and 1.39+0.04  Ma.
Tertiary (?) and Quaternary
Flows of vesicular olivine basalt.  Minor glassy basalt.  Believed to be correlative with Imuruk Volcanics of Bendeleben quad
Pleistocene or Late Tertiary
Dissected, nearly horizontal flows of gray to dark-red vesicular olivine basalt.
Pleistocene or Pliocene
Basalt flows
Vesicular tholeiitic and alkali basalt flows. In Candle and Selawik quadrangles unit includes several alkali basalt cones and flows that contain abundant peridotite inclusions.
K/Ar isotopic cooling ages from the volcanic field in western part of Unalakleet quadrangle range  from 3.25 Ma to 1.39 Ma.
QTa
Andesitic lava
Late Tertiary or early Quaternary
Light to very light-gray vesicular lava.  Removed from final map
Ts
Sandstone, Claystone, Conglomerate, and Lignite
Tertiary
Grayish-white granule conglomerate and sandstone, reddish-brown claystone, and lignite coal.  Exposed at river level at the "Palisades" along the Yukon River.
Pollen of probable Miocene age.
Tcb
Sedimentary rocks
early Tertiary and Miocene
Interbedded polymictic pebble-cobble-boulder conglomerate, grit, and sandstone, with siltstone, shale, and lignite.
Sedimentary rocks, undivided
Tertiary, Eocene
Clay shale and coal
Miocene or Oligocene
Poorly consolidated deposits of gray to brown clay shale, lignitic coal, and yellow volcanic ash
Pollen and spore assemblages from lignite (Seldovian age)
Shale, sandstone, and coal
Miocene? or Oligocene?
Gravel and sand
A small cutbank exposure of moderately dipping gravel and sand at north edge of Selawik Hills on eastern tributary of Mangoak River.  Composed chiefly of poorly sorted granitic rock detritus that appears to have been derived from nearby granitic rocks
Small deposits of nonmarine conglomerate, sandstone, shale, and coal
Poorly consolidated nonmarine deposits.  In the Melozitna and Tanana quadrangles consist of sandstone, claystone, conglomerate, and lignite exposed on south bank of Yukon River near the border of the Melozitna and Tanana quadrangles and small outcrops on
Pollen samples from these five areas range in age from Oligocene to Pliocene.
none
Fault zone rocks
Tertiary or older
Rocks within major fault zones; may be cataclastic or mylonitic, variable ages depending on fault and country rocks
fg
Tvs
Rhyolitic volcanic and sedimentary rocks
Tertiary?
Rhyolitic lava and breccia.  Tuff and welded tuff common.  Cherty rocks minor, thin-bedded or in nodules.
Trs
Tv
Volcanic rocks, undivided
Paleocene to Eocene
Bimodal assemblage of rhyolite and banded rhyolite flow rocks, rhyolitic breccia, tuffaceous sedimentary rocks, and amygdaloidal basalt flow rocks.
Tr
Rhyolite and dacite
Eocene
Composed of finely banded flows, tuffs, breccias, and hypabyssal domal intrusive bodies
Two samples with K-Ar ages, one yielded 50.6 +/- 1.5 on biotite and 47.6 +/- 1.4 hornblende, the other 53.3 +/- 1.6 biotite and 49.1 +/- 1.5 hornblende
Td
Rhyolite domes and flows
Eocene or Paleocene
Well exposed erosional remnants of rhyolite domes and flows and associated basal breccia and tuff
K/Ar age of 56.0+1.7 Ma from sanidine
Kv
Andesitic volcanic rocks
Early Cretaceous
Andesitic crystal-bearing lithic tuff and tuff breccia; probably correlative with andesitic volcanic rocks of Neocomian age in Hughes quad (Patton and Miller, 1966)
Kve
TKv
Volcanic rock
Indian River, and Dulbi River areas- light-gray to pink rhyolite tuff, welded (?) tuff, flows, and breccia.  Subordinate pumice, dark vitrophyre, and obsidian.  Reassigned to Tertiary by Patton (1998), separated from Takhakhdona Hills by Patton (2000)
Obsidian chippings and artifacts found in archeological site in NW AK may have source in obsidian occurrence north of Little Indian River.
Flows in Tanana and Bettles quads have K-Ar date of 58 m.y.
Dacite and rhyolite lava flows, domes, and volcaniclastic rocks
Eocene and Paleocene
Finely banded dacitic and rhyolitic lava flows, basal breccia, tuffs, obsidian, and hypabyssal domal intrusive bodies. Spatially associated with andesite and basalt unit (Ta) and forms a compositionally continuous suite with unit Ta.
K/Ar  isotopic cooling ages range from 60 to 40 Ma.
Horizontal flows of dark vesicular to massive olivine basalt; subordinate volcanic conglomerate and breccia
Tb
Oligocene
Vesicular and columnar-jointed basalt flows and lahar deposits.
Unit yielded a K/Ar cooling age of 32 Ma.
Thr
Hypabyssal rhyolite
Fine-grained porphyritic hyabyssal rhyolite.
Felsic volcanic rocks
Tertiary and Cretaceous (?)
Brown, gray, and light-tan porphyritic flows, breccia, conglomerate, and tuff of acidic and intermediate composition
K/Ar age of 58 =?- 1.7 m.y.
Tda
Tad
Andesite and basalt lava flows and volcaniclastic rocks (Ta) and dacite and rhyolite lava flows, domes, and volcaniclastic rocks (Td), undivided
Confined to west-central part of Melozitna quadrangle where field data are insufficient to map units Ta and Td separately.
Tertiary to Late Cretaceous
Indian River, Takhakhdona Hills, and Dulbi River areas- light-gray to pink rhyolite tuff, welded (?) tuff, flows, and breccia.  Subordinate pumice, dark vitrophyre, and obsidian.  In Takhakhdona Hills also includes dark-green to black vesicular basalt fl
Tvab
Ta
Andesite and basalt flows
Columnar-jointed andesite and basalt flows.  Andesite dominant, basalt much less common.
1,500 m exposure of subaerial columnar-jointed andesite and basalt flows
K/Ar age of 65.2+3.9 Ma  from hornblende in the base of the unit.  Whole-rock K/Ar age of 51.9+1.6 Ma from the top of the unit.
KJv
Andesitic volcanic rocks - Roundabout Mountain volcanic field
Cretaceous and Jurassic(?)
Chiefly porphyritic pyroxene andesite and trachyandesite flows, andesitic crystal and lithic tuff, and massive andesite breccia, agglomerate, and conglomerate.  Commonly altered and therefore pale green.  Interbedded dark-greenish-gray tuffaceous graywac
Andesite and basalt
In Takhakhdona Hills dark-green to black vesicular basalt flows.
Andesite and basalt lava flows and volcaniclastic rocks
Subaerial, columnar-jointed, andesite and basalt lava flows that locally contain interbedded tuffs, breccias, and agglomerates.  Lava flows composed chiefly of pyroxene andesite and less commonly of hornblende-bearing high-silica andesite, olivine-bearin
K/Ar isotopic cooling ages range from 65 to 52 Ma.
K/Ar isotopic cooling ages range from 65 to 52 Ma
Tt
Tuff and tuff  breccia
1,000 m of (1) green intercaldera tuff and tuff breccia, (2) white rhyolite breccia, domes, and ash, (3) highly altered green andesite and dacite flows, and (4) minor pink granite dikes.  500 m of section consists of the green intercaldera tuff and tuff
Tg
Granite
early Tertiary
Light-gray biotite granite, only at Manley Hot Springs
K-Ar(?) 62 Ma
Tpgr
Stock composed of pink to light-gray granite and quartz monzonite.  Fine-grained hypidiomorphic granular or sparsely porphyritic granitic rocks characterized by  plagioclase laths
K/Ar age of 56.2+1.7 Ma from biotite
TKs
Tuff, sandstone, conglomerate, and shale
Early Tertiary and Late Cretaceous
Nonmarine sedimentary rocks rich in volcanic components.  In central part of quadrangle, unit consists of quartz-rich sandstone, conglomerate, siltstone, tuff, tuff breccia, and locally abundant carbonized plant debris.  In southeast part of quadrangle,
TKe
Extrusive rocks
Cretaceous or Tertiary
Basaltic, andesitic, and rhyolitic flows, tuffs, and breccias, and a few dacite flows; interbedded  sandstone and shale.  Flows commonly porphyritic and gently dipping. Probably greater than 500 feet thick.
TKvr
Volcanics
Early Tertiary  and Late Cretaceous
Volcanic rocks of Nixon Fork-Upper Sulukna River area
Latest Cretaceous, earliest Tertiary
Sills, dikes, flows, and plugs of rhyolite, dacite, and trachyandesite.
62-67 Ma
TKnf
Cretaceous  or Tertiary
Basaltic, andesitic, and rhyolitic flows, tuffs, and breccias, and a few dacite flows; interbedded  sandstone and shale.  Flows commonly porphyritic and gently dipping. Probably greater than 500 feet thick.  (Description from RB002, should match on this
TKu
Rhyolite, dacite, andesite, and basalt
Volcanic and hypabyssal rocks of uncertain composition and age
TKva
Basaltic andesite, basalt, and lapilli tuff
Tertiary(?) and Cretaceous
Medium-greenish-gray, aphanitic to fine-grained, porphyritic, hornblende-rich basaltic andesite; uncommon basalt and very fine grained lapilli tuff(?)
OP003
TKad
Andesite and basalt lava flows and volcaniclastic rocks (TKa) and dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks (TKd), undivided
early Tertiary and Late Cretaceous
Dacite, rhyolite, and trachyandesite lava flows, domes, sills, dikes, and interlayered breccias and tuffs.  Composed of phenocrysts of  plagioclase, quartz, sanidine, and biotite in a groundmass of quartz and feldspar.  Locally in Unalakleet and Medfra q
Palynoflora collected from coaly layers at the base of the unit in the Medfra quadrangle are latest Cretaceous (Campanian or Maastrichtian)  in age
K/Ar isotopic cooling ages for this unit  range from 71 to 53 Ma
Volcanic and sedimentary rocks
Tertiary? and or Cretaceous
Porphyritic basalt, andesite, and rhyolite flows, tuffs, and breccias with minor intercalated siltstone and sandstone.  Unit widespread south of the Poorman Fault, volcanic rocks and tuff in Spruce Creek  and Main Creek north of the fault probably correl
TKd
Dikes and subvolcanic rocks
Khi
Hypabyssal intrusive rocks
Cretaceous
Small bodies of hypabyssal intrusive rocks including latite and quartz latite porphyry
Khe
Felsic hypabyssal and extrusive rocks
Cretaceous(?)
Small widely scattered bodies of fine-grained intrusive and extrusive rocks including soda rhyolite, quartz latite porphyry, sanidine trachyte, and quartz diorite.  Some welded tuff at eastern end of Selawik Hills.
TKi
Shallow intrusive rocks of silicic and intermediate composition
Tertiary and Cretaceous
Includes a wide variety of shallow intrusive rocks including rhyolite, dacite, trachyite, and andesite plugs, domes, sills, and dikes and larger more coarsely crystalline bodies of granite, granodiorite, tonalite, and monzonite porphyry
TKgp
TKnr
Volcanic rocks of the Nowitna River area -- rhyolite
Altered rhyolite domes and associated rhyolitic tuff and breccia.
Volcanic rocks of the Sischu Mountains
Light-gray to purplish-red banded rhyolite and dacite subaerial flows and domes, locally containing interlayered breccia and tuff.
66-71 Ma
TKvs
TKsc
Conglomerate, sandstone, and lignite
Conglomerate, sandstone, and lignite.  Lumped in overlying volcanic unit.
TKcg
TKr
Erosional remnants of rhyolite and dacite domes, sills, dikes, and tuffs that are widely distributed throughout the quad.  The rhyolite and dacite of this unit are associated spatially with andesite and basalt flows of unit TKa
K/Ar ages of 69.1+2.1 Ma and 53.2+1.6  Ma from sanadine, 66.8+2 Ma from hornblende, and 66.4+2 Ma from biotite
Shallow intrusive rocks
Shallow intrusive rocks of silicic and intermediate composition.
Dacite and rhyolite flows, volcaniclastic and hypabyssal rocks
Tertiary/Cretaceous
Dacite, rhyolite, and trachyandesite lava flows, domes, sills, dikes, and interlayered breccias and tuffs.  Composed of phenocrysts of  plagioclase, quartz, sanidine, and biotite in a groundmass of quartz and feldspar
Tertiary and or Cretaceous
Dacite and rhyolite flows, domes, and volcaniclastic and hypabyssal rocks
Dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks
Columnar-jointed andesite, basaltic andesite, and basalt lava flows.  Composed of phenocrysts of plagioclase and pyroxene in a fine-grained  groundmass of plagioclase microlites, granular pyroxene, and dark glass
K/Ar isotopic cooling ages range from 64 to 54 Ma
Volcanic rocks
Late Cretaceous and Early Tertiary
Dacite flows, may include tuff and andesite.
TKvd
Late Cretaceous to Early Tertiary
TKn
Volcanic rocks of the Nowitna River area
Latest Cretaceous, Earliest Tertiary
Chiefly subaerial flows of trachyandesite, basaltic andesite, and basalt.  Subordinate intercalated flows and tuffs of rhyolite and dacite.
63 to 64 Ma
TKvn
TKa
Chiefly hornblende andesite, andesite, and basalt lava flows that are widely distributed.  Flows are spatially associated with rhyolite and dacite of TKr
K/Ar ages of 64.4+1.9 Ma, 61.5+1.8 Ma, and 53.8+1.6 Ma
Volcanic and Sedimentary rocks
Tertiary (?) and/or Cretaceous (?)
Porphyritic basalt, andesite, and rhyolite flows, tuffs, and breccias with minor intercalated siltstone and sandstone
TKvi
Andesite and basalt flows and volcaniclastic rocks
Kh
Hypabyssal rocks
Small bodies of primarily dacite and rhyolite porphyry.  These intrusives are widespread in volcanic graywacke and mudstone unit (Kgm) and in andesitic rocks (Kv).
Includes a wide variety of shallow intrusive rocks including rhyolite, dacite, and andesite plugs, domes, sills, and dikes and larger, more coarsely crystalline bodies of granite, granodiorite, tonalite, and monzonite porphyry.
TKc
Mafic to intermediate volcano-plutonic complexes
TKiv
Mafic to intermediate Volcano-plutonic complexes
Altered basalt, andesite, and trachyandesite porphyry flows and hypabyssal intrusive bodies.  Altered mafic and intermediate crystal and lithic tuffs.  Subordinate olivine basalt and dacite flows.
K-Ar ages of 65-71 Ma
TKvc
Volcano-plutonic complexes
Complexes composed primarily of altered basalt, andesite, and trachyandesite porphyry lava flows and hypabyssal intrusive bodies. The complexes also contain altered mafic and intermediate crystal and lithic tuffs and subordinate olivine basalt and dacite
K/Ar isotopic cooling ages  from the unit range from 77 to 65 Ma.
K/Ar isotopic cooling ages  from the unit range from 77 to 65 Ma
Mafic and ultramafic intrusive rocks
Cretaceous and (or) Tertiary
Mafic and ultramafic intrusive rocks including pluglike body of augite andesite porphyry and a small dikelike body of augite peridotite
TKum
TKsa
Dike-like body of dark-brown to gray andesite porphyry.
TKmd
Intrusive rocks
Late Cretaceous(?) or Early Tertiary(?)
Granite, diorite, quartz monzonite, and  may include dikes of varying composition and texture, older intrusives of the greenstone complex (mi), and  hornfelds zones surrounding intrusive rocks.
TKcm
Mafic to intermediate volcano-plutonic complexes -- monzonite
Small bodies of monzonite, quartz monzonite, and granodiorite
TKim
Shallow intrusive rocks - Complex
Shallow intrusive rocks of silicic and intermediate composition.  Complex of many small intrusive bodies
Tki
Intrusive Rocks
early Tertiary or Late Cretaceous
Granite and some diorite. Includes numerous dikes and sills and may include hornfels zones
TKg
White to light gray, fine- to coarse-grained biotite granite.
63-71 Ma
TKq
Quartz monzonite
Early Tertiary-Late Cretaceous
Light- to vey light-gray quartz monzonite, may range to granite
K-Ar(?) 61.8 Ma
Granitic rocks, undivided
Light- to vey light-gray quartz monzonite, may range to granite.
Kg
Granitic rocks
Late Cretaceous?
Granodiorite
K-Ar date of 81.5 to 89.0 Ma from similar plutons in Melozitna quad., however later data suggests Latest Cretaceous or Early Tertiary age from Nulato quadrangle.
Cretaceous-Tertiary
Medium- to coarse-grained equigranular to porphyritic biotite granite composed of anhedral quartz, anhedral to euhedral (porphyritic variety) K-feldspar, anhedral plagioclase and subhedral biotite
K-Ar age of 65.5 +/- 3.3 m.y. from biotite
RB007
Granite-granodiorite
Tertiary to Cretaceous
Granitic rocks of acidic and intermediate composition.  Cheifly syenite at Roundabout Mountain and albite granite on Huslia River-Derby Creek divide.  Maybe other small unmapped granitic bodies intruding andesitic volcanic rocks in northwestern part of q
TKm
Monzonite
Includes monzonite, quartz monzonite, quartz monzodiorite, and monzodiorite.  Subordinate monzogabbro and gabbro
66-70 Ma
Diorite, monzonite, and quartz syenite
Light to medium-gray biotite-aegerine-olivine diorite, monzonite, and subordinate quartz syenite.  Forms bulk of Cripple Creek Mountains pluton.
K-Ar age of 71.3 Ma
MD003
Medium- to coarse-grained, equigranular, biotite and hornblende monzonite, quartz monzonite, monzodiorite, and quartz diorite.  Subordinate monzogabbro and gabbro.
K/Ar isotopic cooling  ages from this unit range from 70 to 66 Ma.
TMg
Tertiary or Late Cretaceous (Not designated on map)
Gabbro
TDg
Undifferentiated gabbro
Devonian to Tertiary
Sills, dikes, and small plutons of gabbro intruding rocks of early Paleozoic and preCambrian(?) age
TDgb
Gabbro and diabase
Tertiary? to Devonian?
Fresh to altered gabbroic and diabasic intrusive bodies.  Unit intrudes rocks as old as middle Paleozoic and as young as Cretaceous.  May represent a wide range of ages.
Fresh to altered gabbroic and diabasic intrusive bodies.  Unit intrudes rocks as old as middle Paleozoic and as young as Cretaceous.  May represent a wide range of ages
PzZrqs
Klc
Limestone conglomerate
Pebble to boulder limestone conglomerate, poorly sorted, locally derived, non-marine
plant fossils of Cretaceous age
Kccc
Kcc
Carbonate-rich conglomerate and sandstone
Late and Early Cretaceous
Nonmarine and marine carbonate-rich conglomerate and sandstone deltaic deposits.
Calcareous graywacke and mudstone
Cyclically interbedded sequence of fine to coarse grained, calcareous graywacke, fine to medium grained carbonaceous, volcanic graywacke, and carbonaceous mudstone.  This unit has been lumped with the eastern part of unit Kcv on the source map and re-lab
abundant carbonized plant debris
Kcvg
Carbonaceous volcanic graywacke and mudstone turbidite deposits
Kcv
Mixed sequence of calcareous graywacke, calcareous mudstone, volcanic graywacke, and volcanic conglomerate.  Transitional between Kvg and Kcg.  Unit added by Patton, 1999 by sub-division.  Consists of carbonaceous volcanic graywacke and mudstone turbidit
Volcaniclastic graywacke and mudstone turbidites
Reassignment of part of unit in extreme northwest part of quadrangle (W.W. Patton, Jr., written commun., 1999).  Dark-gray to green, hard, fine-grained to conglomeratic volcanic graywacke and dark-gray, finely laminated mudstone.  Turbidite assemblage co
Volcanic graywacke and mudstone
late Early Cretaceous (Albian)
Poorly sorted dark greenish-gray volcanic graywacke and mudstone.  Reclassified in northwestern part of quadrangle from NSA = 2180
SH003
Carbonate and volcanic clast graywacke and mudstone
Cyclically interbedded fine- to coarse-grained highly calcareous graywacke; hard, fine- to medium-grained, carbonaceous, volcanic graywacke; and dark carbonaceous mudstone.  Graywacke is typically graded and sole-marked. Carbonized plant debris is abunda
Shallow-water marine mollusks locally abundant but poorly preserved, probably of Early Cretaceous (Albian) age.
Carbonate- and volcanic-clast graywacke and mudstone submarine fan deposits.
Poorly preserved marine mollusks of late Early Cretaceous (?)  age are present in this unit in the Selawik quadrangle
Kcg
Rhythmically interbedded, medium-gray, yellowish-orange weathering, fine-grained to gritty highly calcareous graywacke and micaceous, calcareous mudstone.  Abundant carbonized plant debris.  Unit coarsens westward.  Estimated more than 5,000 feet thick.
Kct
Carbonate-rich sandstone, siltstone, and shale turbidite deposits
Carbonate-clast graywacke and mudstone
Fine-grained to gritty graywacke and laminated micaceous mudstone turbidite deposits composed largely of carbonate detritus and lesser amounts of quartz, chert, volcanic rock, and mica clasts.  Contains abundant carbonized plant debris. The mudstone inte
A single collection of palynomorphs from the Norton Bay quadrangle is Cretaceous in age, possibly late Early or early Late Cretaceous (Albian or Cenomanian).
Poorly sorted nonmarine and shallow-water shelf deposits consisting  of carbonate-rich conglomerate (calcirudite), sandstone (calcarenite), and shale (calcilutite).  Unit contains abundant plant debris and thin seams of bituminous coal.  Clast-supported
Conglomerate facies -- Carbonate-rich conglomerate and sandstone
Conglomerate facies -- Nonmarine and marine carbonate-rich conglomerate and sandstone deltaic deposits.
Nonmarine and marine carbonate-rich conglomerate and sandstone deltaic deposits
Conglomerate facies -- Carbonate-clast conglomerate, sandstone, and shale
Conglomeritic facies of carbonate-rich sandstone, siltstone, and shale turbidite deposits.
Kcgc
Ksh
Late Cretaceous
Shale and siltstone
Ksa
Sandstone
Ksu
Shale, siltstone, and sandstone, undivided
Chiefly dark carbonaceous, generally nonfossilferous shale, siltstone and fine-grained sandstone.  Poorly exposed except where altered to a dark slaty hornfels in the vicinity of plutonic and hypabyssal intrusive rocks. Locally includes a limestone-clast
Kvs
Volcaniclastic sandstone
Kvss
Kss
Fine sandstone, siltstone, and shale
early Late Cretaceous (Cenomanian)
Fine- to medium-grained, dark-greenish-gray, thinly cross-bedded, fossiliferous sandstone and poorly exposed dark-gray siltstone and shale.
Inoceramus concentricus, and I. pictus
uKss
Shallow marine sandstone, siltstone, and shale
Fine-to medium-grained, thinly cross-bedded, fossiliferous sandstone and poorly exposed dark siltstone and shale.  Clasts composed of 40 to 45 percent quartz, 45 to 50 percent volcanic and sedimentary  lithic fragments, and  5 to 15 percent feldspar, chi
Unit contains abundant early Late Cretaceous (Cenomanian) species of Inoceramus.
Ks
Sandstone, Quartz Conglomerate, shale, and siltstone
Probably Late Cretaceous
Non-marine deposits of olive-green, fine- to coarse-grained, crossbedded, quartzose sandstone and grit; quartz-pebble conglomerate, and dark micaeous shale and siltstone.  Ironstone lenses and concretions.  Better sorted and higher percentage of quartz t
Abundant carbonized plant debris
Sandstone, quartz conglomerate, shale, and siltstone, non-marine
Nonmarine and marine undivided sandstone and shale deltaic deposits
Kls
Limy volcaniclastic sandstone
Ksl
Ku
Undifferentiated clastic rocks
Kk
Undifferentiated shale, siltstone, and sandstone
Cretaceous, early and late [possible Permian(?)]
Chiefly dark-gray carbonaceous, largely nonfossiliferous shale, siltstone, and very fine-grained sandstone.  Includes massive limestone conglomerate of uncertain age and stratigraphic affinities.  Conglomerate clasts consist of Paleozoic limestone and un
reworked Paleozoic
KPzsu
Ksc
Sandstone and conglomerate
Kkn
Chiefly fine- to coarse-grained, greenish-gray to gray, thinly cross-bedded "salt and pepper" sandstone and quartz-chert pebble conglomerate.  Poorly exposed interbeds of dark shale and siltstone.
locally abundant plants and fresh and brackish water mollusks
Kqc
Quartz-pebble conglomerate
early Late Cretaceous
Small isolated patches of light-gray quartz-pebble conglomerate and quartzose sandstone.  Minor intercalated with light-colored ashy tuff.  Conglomerate almost wholly of quartz and quartzite clasts.  Intruded and thermally altered by granodiorite (Kg)
Conglomerate with well rounded clasts of quartz, quartzite, graywacke, chert, schist, and mafic volcanic and intrusive rocks; minor sandstone, shale, and thin ash-fall tuff
Abundant plant fossils
Quartzitic conglomerate and quartzite
Early or late Early Cretaceous
Light colored, thermally metamorphosed quartz conglomerate and quartzose sandstone and quartzite
Kq
Quartz conglomerate, sandstone, and mudstone
Conglomerate composed chiefly of white quartz pebbles in quartzose and micaceous matrix; also has pebbles of phyllite, schist, greenstone, and chert in subordinate amounts.  Interbedded quartzose and micaceous sandstone and mudstone.
Age based on correlative rocks in the Baird Mtns. and Selawik quadrangles dated by K-Ar.
Knc
Nonmarine conglomerate, sandstone, mudstone, and coal
Conglomerate composed chiefly of well-sorted white quartz pebbles in quartzose and micaceous matrix; also has pebbles of phyllite, schist, greenstone, and chert in subordinate amounts.  Interbedded quartzose and micaceous sandstone and mudstone.
Abundant well-preserved plant fossils of probable Cretaceous age
Age based on correlative rocks in the Baird Mtns.and Selawik quadrangles dated by K-Ar.
Kc
Conglomerate
Buff to gray, lenticularly bedded, poorly sorted, quartz- and carbonate-rich, pebble and cobble conglomerate; reddish gray, massive to thin bedded, fine- to coarse-grained quartz sandstone; subordinate olive-gray, fossiliferous, mica-rich siltstone, and
Pseudoprotophyllum sp., Castaliites sp., both late Cenomanian
Quartz-clast conglomerate, sandstone, and shale
Composed chiefly of well-sorted and well-rounded clasts of white quartz and/or metagraywacke in a quartzose and micaceous matrix; schist, chert, greenstone, and limestone clasts  occur in subordinate amounts. Conglomerate is interbedded with quartzose, c
Sparse plant fossil collections from this unit range in age from late Early Cretaceous to Late Cretaceous
A K/Ar isotopic cooling  age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle
Quartz-clast congloerate, sandstone, and shale
A K/Ar isotopic cooling age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle
Quartz and metagraywacke-clast conglomerate, sandstone, and shale
SE003
WI004
Quartz- and metagraywacke-clast conglomerate, sandstone, and shale
Plant fossils and thin bituminous coal seams are locally abundant. Sparse plant fossil collections from this unit range in age from late Early Cretaceous to Late Cretaceous.
A K/Ar isotopic cooling  age of 86 Ma was obtained from interbedded ash-fall tuff in Selawik quadrangle.
Shaktolik Group
late Early Cretaceous to Late Cretaceous
Graywacke, shale, grit, and conglomerate.   Type section on the Shaktolik River approximately 120 miles west of the Ruby quad.  Thickness estimated to be more that 4800 feet along the lower Yukon River.  Unit is obsolete and no longer used.  On map, this
plant fossils, marine mollusks
Km
Graywacke, shale, grit, and conglomerate.   Thickness estimated at 4800 feet.  Unit obsolete, no longer shown on map.
Marine mollusks (late Early K) and plant remains (Late K)
Ksg
Sandstone, shale, and conglomerate
Kme
Nonmarine and marine sandstone, shale, and conglomerate deltaic deposits, undivided
Well-sorted, medium- to coarse-grained, light-olive crossbedded sandstone, fine- to medium-grained drark-gray to green silty sandstone, dark-gray micaceous shale, quart-chert-pebble conglomerate, and thin seams of bituminous coal.  Unit is composed of no
Fluvial and shallow marine sandstone and shale, undivided
Nonmarine, fluvial, delta-plain deposits that grade downward into marine delta-front deposits. Fluvial deposits are characterized by fine-grained, locally cross-bedded quartzose sandstone interbedded with micaeous shale and siltstone. Near the base, the
Nonmarine fluvial deposits contain abundant fresh- and brackish-water mollusks and well-preserved plant remains of Late Cretaceous (Cenomanian and Turonian?) age.  Shallow marine deposits contain an abundant molluscan fauna of late Early (Albian) and  ea
Kn
Nonmarine shale, siltstone and sandstone
Nonmarine deposits of drak-gray to olive-gray micaceous shale and siltstone, and light-olive-gray to yellowish-orange, fine- to coarse-grained, crossbedded sandstone.  Massive sandstone beds near base of unit.  Coarse detrital fraction of sandstone chief
Abundant, well preserved flora.
Knm
Undifferentiated sedimentary rocks
Sandstone, shale, and conglomerate deltaic deposits
Chiefly fluvial and shallow-marine deltaic deposits of well-sorted, medium- to coarse-grained, light-olive crossbedded sandstone, fine- to medium-grained, dark-gray to green silty sandstone, dark-gray micaceous shale, quartz-chert-pebble conglomerate, an
Middle Albian to early Cenomanian based on Turrilites acutus, Gastropolites (Gastropolites) kingi, Beaudanticeras (Grantziceras), and Inoceramus sp.; fossil fresh- and brackish-water mollusks; plant fossils, consisting of conifers and angiosperms
K/Ar age of 131 to 158 Ma from detrirtal micas
Sandstone and shale deltaic deposits, undivided
Nonmarine and marine sandstone and shale deltaic deposits, undivided
Undifferentiated sedimentary rocks -- conglomerate facies
Conglomerate facies of sandstone, shale, and conglomerate marine and nonmarine deltaic deposits in southwest part of quadrangle
TKis
Shallow intrusive rocks of silicic and intermediate composition, marine and nonmarine sandstone, shale, and conglomerate, and volcaniclastic graywacke and mudstone turbidite deposits and thermally altered sedimentary rocks
Early Tertiary to Early Cretaceous
TKrs
Rhyolite and dacite, and sandstone, shale, and conglomerate deltaic deposits
Early Tertiary and Cretaceous
Hypabyssal rhyolite and dacite (Early Tertiary and Late Cretaceous) that are too small and too numerous to be mapped seperately at this map scale.  Sedimentary host of thermally altered sandstone, shale, and conglomerate
K/Ar age of 68.8+3 Ma from biotite
Kvc
Intricately intruded areas of Volcanic conglomerate and breccia
Intricately intruded areas of Volcanic graywacke and mudstone, late Early Cretaceous (Albian)
Kvci
TKic
Complex of shallow intrusive rocks (TKi) and Cretaceous sedimentary rocks of Yukon-Koyokuk basin
Igneous pebble-cobble conglomerate
late Early Cretaceous (Albian) may be as young as Late Cretaceous
Massive poorly sorted conglomerate with pebble to cobble sized clasts primarily of mafic intrusive and extrusive rocks and varied colored chert.  Interbedded with fine-grained to gritty (?) , dark-green to green graywacke and mudstone.  grades upward int
Indeterminate pelecypods
Kic
Conglomerate of poorly-sorted clasts of mafic volcanic and intrusive rocks, chert, and graywacke
Late(?) and Early Cretaceous
Massive conglomerate of pebble- to boulder-size clasts.  Interbeds of graywacke and mudstone
Leaf impressions
Massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-sized clasts of mafic extrusive and intrusive rocks in a graywacke and mudstone matrix.
Kmc
Mafic igneous-clast conglomerate, sandstone, and shale
Consists of massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-size clasts in a graywacke and mudstone matrix.  Clasts predominately mafic intrusive and extrusive rocks, varied colored chert, and locally metagraywacke.
Contains marine mollusks of Early Cretaceous(?) age in the Selawik quadrangle
Mafic igneous-clast conglomerate, sandstone, and shale (northern and eastern margin of basin)
Mafic igneous-clast conglomerate, sandstone, and mudstone
Contains marine mollusks  of Early Cretaceous(?)  age in the Selawik quadrangle.
Marine shale and siltstone
Littorial and offshore marine deposits of dark-gray shale and siltstone interbedded with subordinate dark-greenish-gray fine-grained sandstone in lower part and light-olive fine- to coarse-grained crossbedded sandstone in upper part.  Volcanic conglomera
Widespread occurrence of Inoceramus altiflummis (McLearn) of Early Cretaceous (Albian) age
Ksm
Marine deltaic deposits
Pale-olive to gray, fine- to coarse-grained, crossbedded, lenticular sandstone grading down into drak-greenish-gray, fine-grasined sandstone and interbedded dark-gray siltstone and shale.
Marine deltaic deposts
Kms
Shallow marine sandstone and shale
The shallow marine deposits in the lower part of the unit Ks are mapped separately along the Yukon River and in a belt to the west extending from the southern edge of the Norton Bay quadrangle to the western Kateel River quadrangle.  These deposits compo
Shallow marine deposits contain an abundant molluscan fauna of late Early (Albian) and  early Late (Cenomanian) Cretaceous age
KJcs
Clastic sedimentary rocks
Late Jurassic and Cretaceous
Graywacke sandstone, quartzitic sandstone, quartzite, siltstone, shale, slate, slaty argillite, and polymictic conglomerate.
Kvgm
Kgm
Dark-greenish-gray, fine-grained to gritty(?), poorly sorted graywacke composed largely of first- and second-cycle volcanic debris but locally containing abundant granitic and metamorphic rock debris. Graded bedding common,  Dark gray mudstone interbeds.
Poorly sorted dark greenish-gray volcanic graywacke and mudstone.  (Unit replaced by NSA = 1820, per Patton, 2000)
Metasedimentary rocks
Small patches of high-grade metamorphic rocks within Selawik Hills pluton.  Likely to have been of unit Kv in part
K-Ar age of 110 Ma on biotite from metapelite
HFS
Kvm
Volcanic graywacke conglomerate and mudstone
lKvg
Graywacke sandstone and mudstone -- volcanic conglomerate
Early(?) Cretaceous
Massive volcanic conglomerate mapped within unit or poorly sorted, muddy sandstone (graywacke) interbedded with mudstone.  Conglomerate appears gradational with coarse breccias and agglomerates of andesitic volcanic rocks (unit KJv, KT quad.)
Associated and gradational(?) with units containing Buchia of earliest Cretaceous age.
Kvgc
Volcanic conglomerate and breccia
Massive, poorly stratified pebble to boulder conglomerate, interbedded with dark graywacke and dark finely laminated mudstone.  Unit composed of debris flows and alluvial fan deposits.  Consists chiefly of andesitic volcanic rock detritus, but locally in
A granitic clast from conglomerate yielded a K/Ar cooling age of 113 Ma
Calcareous graywacke and mudstone -- conglomerate
Conglomeritic facies of a mixed sequence of calcareous graywacke, calcareous mudstone, volcanic graywacke, and volcanic conglomerate.  Transitional between Kvg and Kcg.  An area of unit Kcv in the south west part of the quadrangle has been reassigned by
Kvcc
Volcanic conglomerate and breccia -- conglomerate
Conglomeritic facies of  volcanic conglomerate and breccia.
Volcanic graywacke, conglomerate, and mudstone
Andesitic volcanic graywacke and mudstone with local amounts of granitic rock detritus and fine-grained tuffaceous material and conglomerate.  Western outcrops of this unit changed to unit conglomeratic facies of unit Kvc by W.W. Patton, Jr. (1999).
Lead-alpha and K/Ar ages of 90 +/- 10 m.y. to 120 +/- 15 m.y.
Volcanic-clast conglomerate, sandstone, and shale
A granitic clast from conglomerate yielded a K/Ar cooling age of 113 Ma.
Kwc
Wilber Creek unit of Weber and others (1992)
Interlayered siltstone, shale, sandstone, and conglomerate.  Impure graywacke rich in volcanic detritus is locally characteristic and probably correlates with the Kathul Graywacke of the Charley River quadrangle.
Kffg
Kwcq
Wilber Creek unit of Weber and others (1992), quartzite
Brown, argillaceous, impure quartzite and graywacke sandstone; locally mappable within dominantly argillaceous and graywacke section.
Quartz-carbonate sandstone and pebbly mudstone
Early Cretaceous (Valanginian, Hauterivian, Barremian, Aptian)
Fine- to coarse-grained quartz-carbonate sandstone and conglomerate, quartzose limestone and dark-gray pebbly mudstone and siltstone.
Buchia sublevis, B. crassicolis, Cylindroteuthis, Inoceramus, Acroteuthis, Tropaeum
Graywacke sandstone and mudstone
Chiefly medium- to dark-gray mudstone and medium-gray to dark-greenish-gray moderately to highly calcareous fine-grained sandstone..  Sandstone locally contains thin lenses of feldspar and chert grit.  Mudstone commonly banded and finely cross-bedded.
Graptolites of Early Cretaceous age (Albian) age in adjoining Nulato quadrangle.  Not sure what unit though (Ks on pub. map but this doesn't match)
Kcs
Calcareous sandstone, siltstone, and shale turbidite deposits
Fine- to coarse-grained, dark-greenish-gray, moderately to highly calcareous, turbiditic sandstone interbedded with dark-gray shale  and siltstone
Offshore calcareous sandstone, siltstone, and shale
Fine- to coarse-grained, moderately to highly calcareous, turbiditic sandstone interbedded with dark-gray shale and siltstone.  The sandstone occurs in beds 20 to 40 inches (50 to 100 centimeters)  thick grading upward into finely cross-laminated, muscov
Unit contains sparsely distributed ammonites of late Early Cretaceous (Albian) age and is interpreted as a prodelta facies approximately correlative in age with the marine sandstone, siltstone, and shale deltaic deposits of unit Kms.
Ungalik Conglomerate
Conglomerate, grit, some graywacke.  Boulders as much as 2 ft in diameter: Sorting and bedding poor.   Believed  to be several hundred ft thick on the Melozitna River north of the Ruby quad.   Patton and Bickel estimate minimum thickness of 1200 feet.  S
Kuc
Ungalik conglomerate
Creteaceous
Conglomerate, grit, some graywacke.  Clasts are angular to rounded.  Sorting and bedding are poor.  Boulders as much as 2 feet in diameter.  Type section is near the Ungalik River west of Nulato quad.  Thickness believed to be at least several hundred fe
Kgs
Poorly sorted, muddy sandstone (graywacke) interbedded with mudstone.  Chiefly dark-greenish-gray to pale-olive tuffaceous and feldspathic, fine- to very coarse-grained sandstone and subordinate dark-gray mudstone.  Abundant lenses of feldspar and chert
Volcaniclastic graywacke and mudstone turbidite deposits
Dark-gray to green, hard, fine-grained to conglomeratic, volcanic graywacke and dark-gray finely laminated mudstone.  Graywacke composed of  matrix supported intermediate and mafic volcanic and intrusive rock and chert clasts. quartz and metamorphic rock
Kvg
Andesitic volcanic graywacke and mudstone with local amounts of granitic rock detritus and fine-grained tuffaceous material and conglomerate
Hard, fine-grained to conglomeratic, locally tuffaceous, graywacke and dark-gray finely laminated mudstone. The graywacke is composed of matrix-supported clasts of intermediate and mafic volcanic and intrusive rocks and chert.  Clasts of quartz and of me
Marine mollusks of late Early Cretaceous (Albian) age  were identified in this unit in the Bettles, Hughes, and Kateel River quadrangles
Fine- to coarse-grained, poorly sorted graywacke interbedded with mudstone
Ammonites and pelecypods of Albian age
Graywacke and mudstone
Fine- to medium-grained, locally calcareous, poorly sorted graywacke interbedded with mudstone
Marine mollusks; Grantziceras and Cleoniceras
Poorly sorted dark greenish-gray volcanic graywacke and mudstone.
Chiefly dark-greenish gray to pale-olive tuffaceous and feldspathic fine-to-very coarse-grained sandstone.  Subordinate dark-gray mudstone.  Many sandstone beds distinctly mottled due to partial zeolitization of volcanic material.
Association and gradational(?) with units containing Buchia of earliest Cretaceous age.
Undifferientiated units Km and Kn.  Units on east side of quadrangle reassigned to unit Kvg (NSA 2180).
Turbidite deposits
Graywacke and mudstone turbidite deposits.  Polygons in extreme northwest of quadrangle of this unit reassigned to unit Kgw on Wilson and others (1998), lumped back by W.W. Patton, Jr., (1999)
Mixed sequence of calcareous graywacke, calcareous mudstone, volcanic graywacke, and volcanic conglomerate.  Transitional between Kvg and Kcg.  Small area of unit in northeast part of quadrangle reassigned and lumped with unit Kvm by W.W. Patton, Jr. (19
Sub-division of volcaniclastic graywacke and mudstone turbidite deposits (Patton, written commun., 1999).  Dark-gray to green, hard, fine-grained to conglomeratic volcanic graywacke and dark-gray, finely laminated mudstone.  Turbidite assemblage consisti
Volcanic-clast graywacke and mudstone submarine fan deposits.
Volcanic-clast graywacke and mudstone sumbmarine fan deposits
Volcanic-clast graywacke and mudstone submarine fan deposits
Volcanic-clast graywacke and mudstone
Marine mollusks of late Early Cretaceous (Albian) age  were identified in this unit in the Bettles, Hughes, and Kateel River quadrangles.
Volcanic graywacke and conglomerate
Kcvs/Kcs
Coarse-grained volcaniclastic sandstone and conglomerate
earliest Cretaceous
Greenish gray, poorly sorted fine- to coarse-grained lithic-volcaniclastic sandstone and pebble conglomerate composed chiefly of volcanic rock and chert detritus, and quartz.
Inoceramus
Poorly sorted fine- to coarse-grained graywacke, sandstone, grit, and pebble to cobble conglomerate composed chiefly of volcanic rock and chert detritus; interbedded dark mudstone.
Kgc
Early Cretaceous?
Poorly sorted fine- to coarse-grained graywacke sandstone, grit, and pebble to cobble conglomerate composed chiefly of volcanic rock and chert detritus. Interbedded dark mudstone. Unit is tentatively assigned an Early Cretaceous age.
It locally contains abundant shell prisms thought to have been derived from large- shelled Early Cretaceous species of Inoceramus.
Kfv
middle Cretaceous
Varies locally, consists of latite, quartz latite, and trachyte flows, crystal-lithic tuff, rhyolitic and rhyodacitc welded tuff and flow(?) and hypabyssal intrusive rocks.
Biotite from tuff yielded 85.2 Ma K-Ar age (not recalculated with new constants)
Kac
Agglomerate, chert, tuff, and sandstone
Kvl
Ktg
Tuff, volcanic graywacke, and mudstone
Volcaniclastic rocks of andesitic and dacitic composition.  Crystal-lithic tuff, lithic tuff, volcanic graywacke and mudstone.  Rare andesite flows.  Mapped only along northern edge of this quad and in adjoining HU quad.  Overlies Kv and may grad lateral
Andesitic and latitic volcaniclastic rocks including crystal -lithic tuff, lithic tuff, volcanic graywacke, and mudstone
Chiefly crystal and lithic tuffs and volcanic graywacke interbedded with laminated mudstone. Tuffs and graywacke characterized by abundant potassium feldspar crystals and potassium-rich volcanic rocks fragments.  Unit contains rare mafic and intermediate
Unit contains dinoflagellates of late Early Cretaceous (Hauterivian,  Barremian, and possibly Aptian) age.
Earliest Cretaceous (Neocomian) but may include Albian age strata
Koyukuk River- Pillow basalt and andesitic flows; andesitic tuffs, volcanic conglomerate, and breccia; chert and fine-grained cherty tuff; coquinoidal limestone composed largely of Buchia sp. Widely altered to a hard dark green hornfels.  Dulbi-Melozitna
Buchia sublaevis, belemnite; Buchia cf.B. crassicollis; Buchia keyserlingi
Buchia subokensis of earliest Cretaceous age in interbedded sedimentary rocks.
Andesite and basalt flows, volcaniclastic rocks, and soubordinate rhyolite and dacite flows.
Andesitic volcaniclastic rocks
Dark-greenish-gray crystal and lithic tuff, fine cherty tuff, tuff breccia, and volcanic sandstone and conglomerate.  Koyukuk terrane
Buchia sublaevis Keyserling (Valanginian age), brachiopods, radiolarians (Valanginian age)
earliest Cretaceous (Neocomian) but may include Albian age strata
Jurassic (?) and Cretaceous
Wide variety of andesite volcanic flows and volcaniclastic crystal and lithic tuffs.  Mainly andesitic and trachyandesitic crystal and lithic tuffs, tuffaceous volcanic graywacke, masssive andesitic breccia, agglomerate, and conglomerate
Simbirskites ammonite of Early Cretaceous
K/Ar age of 120 +/- 3 m.y.
Late Jurassic and Early Cretaceous
Volcanic rocks including andesitic crystal-bearing tuff, tuff brecia, and agglomerate intercalated with porphyritic pyroxene andesite and trachyandesite flows
Buchia sublaevis (Keyserling) and B. crassicollis (Keyserling) both of Neocomian age
K/Ar og 134 +/- 5 m.y. of volcanic rocks
Kab
Porphyritic andesite and basalt
Chiefly greenish-gray and dark-reddish porhyritic andesite and basalt flows and shallow intrusive rocks.  Pillows and columnar jointing common.
K-Ar age of 125 Ma on andesite porphyry and 122 Ma on latite plug.
earliest(?) Cretaceous and Jurassic(?)
Chiefly dark greenish-gray, andesitic crystal-bearing lithic tuff, volcanic breccia, and volcanic conglomerate with subordinate intercalated trachy andesite and basalt flows.  Minor volcanic graywacke and mudstone.
Abundant Buchia sublevis of earliest Cretaceous locally.
Quartz latite porphyry yielded K-Ar age of 117 Ma on hornblende
Chiefly andesitic crystal-bearing lithic tuff, volcanic breccia, and volcanic conglomerate with subordinate intercalated andesitic flows.
lKv
KJv?
Kab?
Flows of andesite and basalt, interbedded with tuff, tuff breccia, agglomerate, volcanic conglomerate, and volcanic graywacke.   Flows typically  have phenocrysts of  plagioclase and pyroxene set in a matrix of devitrified glass, altered plagioclase micr
Unit contains abundant marine mollusks of early Early Cretaceous (Berriasian and Valanginian) age.
K/Ar isotopic cooling ages range from 137 to 120 M.
K/Ar isotopic cooling ages range from 137 to 120 Ma.
n upper part of the unit, the tuffs are highly calcareous and contain abundant shelly debris, including species of Buchia
Kbd
Spilitic pillow basalt and diabase
Early Cretaceous(?)
Dark greenish- to reddish-brown, fine-grained, spilitic amygdaloidal pillow basalt flows and dark-greenish-gray, medium- to coarse-grained, spilitic diabase intrusive rocks.
Dark greenish- to reddish-brown, fine-grained, spilitic amygdaloidal pillow basalt flows and dark-greenish-gray, medium- to coarse-grained, spilitic diabase intrusive rocks.  Unit added  in northwest corner by Patton (2000).
Kft
Shoshonitic flows and tuffs
Dark-gray to green lithic tuffs, pillowed flows, diabase, and volcanic conglomerate of shoshonitic composition.  Koyukuk terrane
K/Ar age of 117+3.5 Ma and 118+3.5 Ma from biotite
Granitic rocks of acidic and intermediate composition  Chiefly syenite at Roundabout Mountain and albite granite on Huslia River-Derby Creek divide.
Cretaceous?
Ray Mountains pluton and part of another large pluton at north central edge of quadrangle.  Quartz monzonite, granite, monzonite, and possibly granodiorite.
Kag
Albite granite
Cretaceous (?)
Leucocratic medium- to coarse-grained albite granite composed predominately of albite and quartz
Fine- to medium-grained  hornblende-biotite granodiorite with subordinate quartz monzonite and quartz diorite.  (Recoded NSA 2420 March, 1999, per Bill Patton.)
K-Ar date of 82.3 and 89.0 m.y. from the Dulbatna Mountain pluton and 81.5 m.y. from the Indian Mountain pluton in adjoining Hughes quad
Kgd
Kg3
Granodiorite and quartz monzonite
Chiefly leucocratic, medium-grained, hornblende-biotite granodiorite and quartz monzonite in Zane Hills and Wheeler Creek plutons
K-Ar ages of 80.6 and 81.9 Ma
Kgq
Medium-grained hornblende-biotite granodiorite and quartz monzonite with lesser diorite
K/Ar age of 82 +/- 3 m.y.
Granodiorite and granite
Generally fine- to medium-grained equigranular, but locally porphyritic, hornblende-biotite granodiorite, and alaskitic biotite granite.   Locally includes tonalite and quartz monzodiorite.
K/Ar isotopic cooling ages range from 89 to 78 Ma.
Mafic rocks
Gabbro, diorite?  Not on published OFR98-133
Kgbm
Ka3
Alaskite
Medium-grained alaskite at west end of Wheeler Creek plutons
Granitic rocks of uncertain composition, texture, and age; may be equivalent to KG unit of Melozitna quadrangle (MZ002)
Two small plutons in the se part of quadrangle.  Fine- to medium-grained  hornblende-biotite granodiorite with subordinate quartz monzonite and quartz diorite.  Distinguished from others to the north by Bill Patton (March, 1999)  ERROR -- not on map, sho
Medium- to coarse-grained equigranular to porphyritic biotite granite
K-Ar age on biotite 65.5 +/- 3.3 Ma
Kcm
Granitic rocks of Christmas Mountain pluton
uKgs
Quartz monzonite, granite, monzonite, and possibly granodiorite
K-Ar(?) 92, and 90 Ma; 104 Ma
Granitic rocks of coarsely porphyritic biotite quartz monzonite.  Sub divided by source BT003 into NSA 2530 and 2545
K/Ar age of 106 +/- 3.0 m.y.
Ksp
Serpentinite and mafic rocks
Serpentinite, diabase-gabbro and some metadiorite.  Not on published OFR98-133
Kum
lKgg
Nepheline syenite
Quartz Monzonite
Pinkish coarse-grained porphyritic biotite quartz monzonite.  Becomes gnessic in southern part of the Melozitna pluton.  Altered and slightly cataclastic in small pluton east of Gold Mountain.
K-Ar date 111 m.y. from Melozitna pluton
Kqm
Kgr
Khotol pluton, a large, poorly exposed granite 12 by 20 km in size.  Granite is typically coarsely porphyritic having large K-spar phenocrysts in a moderately coarse groundmass.
K-Ar age of 112 +/- 3.4 Ma on biotite
Part of Melozitna pluton.  Quartz monzonite, granite, monzonite, and possibly granodiorite.
Medium-grained hornblende-biotite granodiorite and quartz monzonite with lesser diorite  (Single small pluton in middle of quadrangle (per Bill Patton, March, 1999)
.
Kq2
Chiefly leucocratic, medium-grained porphyritic, biotite quartz monzonite in Purcell Mtn. and Ekiek Creek plutons
K-Ar age of 98.6 Ma for Purcell Mtns. pluton
Kqi+
Quartz monzonite and alaskite
Chiefly leucocratic, fine- to medium-grained cataclastic-textured, monzonite and alaskite
K-Ar age of 99 Ma
probably Late Cretaceous and Early Cretaceous
Chiefly quartz monzonite in Kokrines Hills
K-Ar date of 111 Ma in Melozitna quad.
Consists chiefly of biotite and muscovite-biotite granite and granodiorite.
K/Ar isotopic cooling  ages range from 112 to 96 Ma and two U/Pb zircon analyses give crystallization ages of 112 and 109 Ma
Granitic rocks of hornblende and pyroxene monzonite and syenite.  Minor biotite quartz monzonite.  Unit subdivided by Patton (1999, 2000)
lead-alpha age of 90 +/- 10 m.y. and 100 +/- 15 m.y.  K/Ar age of 102 +/- 5 m.y. and K/Ar age of 100 +/- 5 m.y.
Granite and granodiorite
K/Ar isotopic cooling  ages range from 112 to 96 Ma and two U/Pb zircon analyses give crystallization ages of 112 and 109 Ma.
Kn2
Chiefly leucocratic, medium-grained nephelene syenite and related mafic alkaline rocks
K-Ar age of 107 Ma from Selawik quadrangle
Kns
Chiefly leuco- to melanocratic, medium-grained nephelene syenite and malignite, with subordinate ijolite, shonkinite, and pyroxenite.
K-Ar age of 107 Ma
Knsy
Ksy
Km2
Chiefly leucocratic, medium-grained porphyritic, biotite-pyroxene monzonite
K-Ar age of 99.4 Ma
Ks2
Syenite
Chiefly leucocratic, medium-grained gniessic hornblende syenite
K-Ar age of 100 Ma from Selawik quadrangle
Kgi
Syenite and monzonite
Chiefly leuco- to mesocratic, medium-grained gniessic syenite and monzonite
K-Ar age of 100 Ma
Syenite-monzonite
Composed of syenite, monzonite, and subordinate quartz monzonite, monzodiorite, quartz syenite, and nepheline syenite and related mafic alkaline rocks including malignite, ijolite, shonkinite, and pyroxenite
K/Ar isotopic cooling ages from units Ksy and Knsy range from 113 to 99 Ma
Ktt
KJwc
Wilber Creek and Wolverine quartzite units, undivided
Cretaceous and Jurassic
Wilber Creek and Wolverine quartzite units, undivided (TN003 modified, shown as southern TrPs)
KJw
Wolverine quartzite unit of Weber and others (1992), undivided
Early Cretaceous and or Jurassic
Light-gray quartzite and dark-gray, cleaved, subphyllitic argillite and shale, part of unit KJcs of Chapman and others.
KJwq
Wolverine quartzite unit of Weber and others (1992), quartzite
Light-gray  to tan, white weathering, massive-bedded, moderately well-sorted, subrounded fine- to medium-grained quartzarenite.  Correlative with Keenan Quartzite of Charley River quadrangle according to Dover but I wonder if this is the wrong unit and i
KJwa
Wolverine quartzite unit of Weber and others (1992), sandstone and shale
Dominantly gray to black argillaceous rocks containing interbeds of Wolverine-type quartz-arenite.
Jt
Trondhjemite and tonalite
Late and Middle Jurassic
Trondhjemite, tonalite, and subordinate quartz diorite, diorite, and gabbro forming a long pluton from Unalakleet River valley into the Holy Cross quad.  Koyukuk terrane
5 K/Ar ages of 154+6 Ma from trondhjemite biotite, 166+7 Ma, 173+9 Ma from tonalite biotite and hornblende, and 148+4.4 Ma and 130+3.9 Ma from tonalite hornblende
pc
Cumulate ultramafic rocks of Mount Hurst
Unknown
Cumulate ultramafic rocks of Mount Hurst: relations uncertain
Jtu
Jcu
Cumulate ultramafic rocks
Middle and Late Jurassic
Predominately dunite but also includes wehrlite and olivine clinopyroxenite.  Two exposures of massive chromotote as much as 1.5 m thick noted in dunite.
ph
Harzburgite tectonite of Mount Hurst
Harzburgite tectonite of Mount Hurst; relations uncertain
Jht
Harzburgite tectonite
Harzburgite composed of 20-30 percent orthopyroxenite and as much as 75 percent olivine and minor clinopyroxene and spinel.
JPu
Ultramafics
Permian to Jurassic
Small bodies of serpentinized peridotite and dunite with closely associated gabbro and anorthosite.
Ju
Ultramafic rocks
Late Jurassic
Juu
Ultramafic rocks, undivided
Partly serpentinized peridotite and dunite intruded by narrow dikes of fresh clinopyroxenite, horblendite, gabbro, and gabbro pegmatite.
Ultramafic-mafic complexes
Chiefly dark greenish-black serpentinite and serpentinized pyroxenite, peridotite, and dunite with locallized subordinate gabbro.  Koyukuk terrane
Jurassic (?), Triassic (?), and Permian
Ultramafic rocks of serpentinized peridotite and dunite
Jaum
Jdr
Dishna River mafic and ultramafic rocks
Jurassic
Dishna River mafic and ultramafic rocks extension into Ophir quadrangle
Jumc
Mafic-ultramafic complexes
The complexes consist of: 1) a cumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a
K/Ar isotopic cooling ages from the magmatic suite average 159 Ma and two 40Ar/39Ar determinations yielded a plateau age of 162 Ma.  K/Ar isotopic cooling ages from the metamorphic sole at the base of the complexes range from 172 to 155 Ma and one 40Ar /
MzZum
MzPzum
Mafic-ultramific complexes
Mesozoic and Paleozoic?
Complexes consist of 3 suites, 1., a cumulate magmatic suite of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2., amantle suite of harzburgite, dunite, and minor clinopyroxenite, and 3., a metamorphic sole of a highly tectonized lay
Mafic-ultramfic complexes
The complexes consist of: 1) acumulate magmatic suite composed of interlayered dunite, wehrlite, olivine clinopyroxenite, and gabbro, 2) a mantle suite composed of harzburgite, dunite, and minor clinopyoxenite, and 3) a metamorphic sole consisting of a h
JTrt
Cherty tuff, crystal and lithic tuff, and volcanic breccia
Triassic and possible early Jurassic
Dark-greenish, very fine grained cherty tuff grading into greenish-gray radiolarian chert.  Fine to coarse-grained dark greenish-gray crystal and lithic tuff.  Volcanic breccia and conglomerate composed of poorly sorted clasts of mafic volcanic rocks and
Radiolaria and conodonts
JTrta
JTrt; JTrma
Siliceous tuff, crystal and lithic tuffs, and metasiltstone and Mafic volcanic breccia, tuff, siltstone, chert, and agglomerate
Triassic and early Jurassic
Radiolaria and conodonts reported by Patton and others, 1980 (MD002)
JMc
Chert, argillite, and volcaniclastic rocks
Triassic, Permian, Pennsylvanian, and Mississippian
Chiefly banded radiolarian chert  interbedded with argillite, cherty  tuff, fine- to coarse-grained crystal and lithic tuff, and volcanic breccia and conglomerate.  Breccia and conglomerate are composed of poorly sorted clasts of mafic volcanic rocks and
Abundant radiolaria ranging in age from Mississippian to possibly as young as Jurassic
TrMc
Cherty tuffs, chert, argillite, graywacke, crystal-lithic tuffs, volcanic breccia, and conglomerate
Chert, cherty tuff, argillite, crystal-lithic tuff, volcanic breccia, and conglomerate
Jurassic? to Mississippian
Unit contains abundant radiolaria ranging in age from Mississippian to possibly as young as Jurassic.
Spiculite and sandy limestone
Late Triassic (Norian)
Dark-gray banded spiculite and chert, yellowish-orange-weathering sandy fossiliferous limestone and conglomerate and dark-gray shale
Monotis ochotica, M. of M. scutiformis, Halobia, Heterastridium
Trsl
Trc
Carbonatite
Triassic
Magnetite-rich carbonatite.
TN005
Jsc
Serpentinite and or carbonatite
Jurassic?
Carbonatite of unit Jsc
Ps
Slaty shale, siltstone, graywacke, and conglomerate
Permian
Moderately well-indurated, medium- to dark-gray shale, commonly weakly foliated to slaty, and in part phyllitic.  Well indurated, medium- to medium-drak-gray siltstone, in part argillite.
TrPs
Permian to Triassic
Dominantly dark-gray, typically phyllitic, silicieous to carbonaceous argillite and shale, having subordinate but characteristic clast-supported chert-rich conglomerate, greenish-gray chert, tuffaceous volcaniclastic rocks, yellowish- to reddish-brown hi
JMr
Rampart Group and associated mafic intrusive rocks, undivided
Mississippian to Jurassic
Rampart Group volcanic and sedimentary rock sequence
TrMts
m
Marble
Age not given
Blocks of bedded or massive marble of unknown age or affinity in melange of unit MzPzm.  Polygons in unit KJm assigned NSACLASS of 5200
c
Metachert
Sinlge block of bedded metachert in melange of  MzPzm.  Other blocks in unit KJm assigned NSACLASS of 5200
TrMs
Sandstone, grit, and argillite
TrMis
Pg
Graywacke
Unit probably correlative with similar clastic rocks of the Permian(?) Rampart Group.  Unit has three parts; a) fine- to medium-grained, medium-gray to dark-greenish-gray graywacke, calcareous in part and containing some dark-gray shale fragments, b) gri
Nodosinellids (Tetrataxis), bryozoan and echinoderm debris.
TrMv; TrMcs
Mafic tuff, volcaniclastic sandstone, and minor mafic flows and Calcareous, lithic pebble sandstone
Triassic to Mississippian
Medium- to dark-gray, coarse-grained augite-plagioclase-rich mafic tuff, volcaniclastic sandstone, and porphyritic basaltic andesite and basalt.  Also, light- to medium-green-gray, medium- to coarse-grained, commonly calcareous lithic pebble sandstone an
Veghicyclia spp., Pseudoheliodiscus spp., and Sarla spp. of Norian age and Crytostome bryozoan, brachiopod and pelmatozoan fragments of probable late Paleozoic age
TrMg
Graywacke, grit, and argillite
Triassic? to Mississippian?
Fine- to medium-grained, commonly calcareous graywacke and granule conglomerate, which contain clasts of chert, shale, argillite, and volcanic rocks.   Graywacke and conglomerate are interbedded with argillite
Unit contains microfossils and bryozoan and echinoids fragments assigned  to a Permian(?)  age in the Ruby quadrangle and assigned more generally to a late Paleozoic age in the Ophir quadrangle.  Unit appears to interfinger locally with unit TrDc
Fine- to medium-grained, commonly calcareous graywacke and granule conglomerate, which contain clasts of chert, shale, argillite, and volcanic rocks.   Graywacke and conglomerate are interbedded with argillite.  Unit appears to interfinger locally  with
Unit contains microfossils and bryozoan and echinoids fragments assigned  to a Permian(?) age in the Ruby quadrangle and assigned more generally to a late Paleozoic age in the Ophir quadrangle.
Banded chert and argillite
Medium- to dark-gray, green, and some red radiolarian chert, interbedded dark-gray argillite, and very minor tuffaceous volcanic rocks.  Not on current map
Albaillella sp.(Middle and Late Mississippian), Latentibifistula sp. (Pennsylvanian and Permian), Capnodoce sp. (Triassic?)
TrMica
Pzmi
Intermediate to mafic intrusive rocks
Paleozoic
Fine- to medium-grained gabbro, subordinate quartz diorite, quartz monzonite, orthopyroxene gabbro, and pyroxenite.  Commonly sill-like.  Wallrocks are restricted to the Rampart Group
JPztm
vr
unknown
Chiefly basalt and andesite.  Rarely rhyolite, tuff, chert, agglomerate, and breccia.  Probably of several different ages.  Not shown on map as this unit, rather is NSACLASS 1000 and 2330
MzPzv
Rampart Group volcanic and sedimentary rock sequence, mafic rocks divided out
JTrtmu
JMms
Mafic and sedimentary rocks
TrMru
TrMbc
Pillow basalt, chert and minor argillite
Altered aphanitic and porphyritic pillow basalt.  Phenocrysts in the porphyritic basalt are composed chiefly of olivine and pyroxene.  Basalt is interlayered with chert and subordinate beds of agglomerate containing clasts of basalt and chert
Chert contains bryozoans and radiolaria of late Paleozoic and possibly Triassic age
TrMtsu
Pillow basalt, chert, and minor agglomerate
Altered aphanitic and porphyritic pillow basalt.  Phenocrysts in the porphyritic basalt are composed chiefly of olivine and pyroxene.  Basalt is interlayered with chert and subordinate beds of agglomerate containing clasts of basalt and chert.
Chert contains bryozoans and radiolari a of late Paleozoic and possibly  Triassic age.
JMtru
mi
Metamorphic igneous rock
Carboniferous (?) Late Paleozoic
Greenstone, locally some gray to red chert, greenstone tuff, and graywacke. Greenstone altered from basalt, diabase, and andesite extrusives and diorite, diabase, gabbro, and pyroxenite intrusives.  In Nulato quad assigned a Carboniferous(?) age.  May in
JMtu
Pzrgs
Rampart Group
Argillaceous and arenaceous rocks, siliceous and calcareous chemical sedimentary rocks and volcanic rocks.  Pzrgs is of a lower metamorphic grade than Pzrgmsv and consists of gray, green, black, and tan slate and siltstone interbedded with green to gray
Limestone near Yuki mountain yielded a Devonian fossil age, considered highly suspect
Pzrgmsv
Argillaceous and arenaceous rocks, siliceous and calcareous chemical sedimentary rocks and volcanic rocks.  Pzrgmsv is of a higher metamorphic grade than Pzrgs and consists of phyllite or fine-grained quartz-muscovite-chlorite schist intercalated with me
JPb
Basalt and diabase
Permian to Jurassic.
Spilitic basalt and diabase largely altered to greenstone.  Along contact with Km, altered to mafic hornfels.   Probably correlative with similar rocks on strike to the NE in the Tanana and Bettles quads
TrMb
Basalt, gabbro, and chert
JMab
Altered basalt, gabbro, and chert
Mississippian to Triassic
Variably altered and metamorphosed dark-green to gray flows and shallow intrusives of basalt, diabase, and gabbro locally interlayered with volcaniclastic rocks of basaltic composition, bedded chert, and argillaceous rocks
Basalt and diabase of Rampart Group
Jurassic to Permian
Basalt and diabase of Rampart Group.
JMbc
Basalt and chert
Mississippian to Jurassic?
Dominantly basalt, altered basalt, and subordinate diabase and a low-grade cataclastic assemblage of generally dark gray chert and silicieous argillite.  Also subordinate volcaniclastic rocks and minor Mississippian limestone
Spilitic basalt and diabase largely altered to greenstone.  Along contact with Km, altered to mafic hornfels.   Probabaly correlative with similar rocks on strike to the NE in the Tanana and Bettles quads
Jv
Altered mafic volcanic rocks
Volcanic rocks including aphanitic amygdaloidal andesite and basalt flows; possibly correlative with rocks of Christian quadrangle (Reiser and others, 1965)
K/Ar age of 155 to 168 m.y.
Mafic volcanic rocks
Jurassic (?)
Chiefly dark-greenish gray basalt flows and diabase intrusives; commonly altered or partially altered to aggregate of chlorite, epidote, and sodic plagioclase
K-Ar ages of 155 and 168 Ma in the Christian quadrangle.
Dark-greenish gray altered basalt and diabase; commonly altered or partially altered to aggregate of chlorite, epidote, and sodic plagioclase
b
Metabasalt
Metabasaltic rock of unknown age, not as a separate mappable unit(?), but of significant size within other units to warrant distinction on the map.  Polygons associated with unit MzPzm included here.  Other polygons in units DOb and KJm, assigned NSACLAS
JDv
Altered basalt, gabbro, and chert.
Jurassic and Devonian
Variably altered and metamorphosed flows and shallow intrusives of basalt, diabase, and gabbro interbedded with varying proportions of chert, argillite, slate, phyllite, volcaniclastic rocks,  graywacke, and carbonate rocks. The basalt, diabase, and gabb
Altered basalt, gabbro, chert, interbedded with argillite, tuffs, and graywacke
Jurassic to Devonian
Altered basalt, gabbro, chert, argillaceous rocks, tuff, graywacke, and carbonate rocks
Radiolaria from chert  in this unit range in age from Devonian to Jurassic.  Sparse megafossils from the carbonate rocks range in age from Devonian to Permian. The carbonate rocks in the lower part of the unit contain redeposited shallow-water conodont f
JPv
Mafic volcanic and intrusive rocks
Mafic volcanic and intrusive rocks including pillow basalt, diabase, and gabbro; subordinate basaltic and andesitic volcaniclastic rocks, chert, and cherty mudstone
Foraminifera and brachiopoda of Permian age
JDu
Undifferentiated altered volcanic rocks and phyllite
Devonianÿto Jurassic
Mafic volcanic rocks (Jv) and phyllite (Dp) in complex fault and intrusive relationships.  Unit replaced on published coverage per Patton (Class 205, NSA 5145)
Tectonite
MzPzl
KJm
Melange
Cretaceous and (or) Jurassic
Tectonic melange
Radiolarian chert of Pennsylvanian or Permian age
Kmk
MzPzm
Melange and phyllite
Mesozoic to Paleozoic
Dark gray to black siliceous phyllite with fault-bounded blocks of marble, ribbon chert, dolostone, metabasite, schist, and serpentinite.
Blocks of bedded metachert in melange of unit KJm.  Single polygon in unit MzPzm assigned NSACLASS of 5020.
Jsch
cs
Chlorite schist
Blocks of chlorite schist in melange of MzPzm.
Blocks of bedded or massive marble of unknown age or affinity in melange of unit KJm.  Polygons in unit MzPzm assigned NSACLASS of 5020
Mesozoic and Paleozoic
Melange consists of blocks of carbonate rocks, chert, metagraywacke, and altered mafic volcanic and intrusive rocks in a matrix of phyllite.  Within the melange unit the large blocks of carbonate rocks from units  |ca and |cr  and altered basalt, diabase
Melange in a matrix of phyllite
Melange consists of blocks of carbonate rocks, chert, metagraywacke, and altered mafic volcanic and intrusive rocks in a matrix of phyllite.  Within the melange unit the large blocks of carbonate rocks from units  Pzca and Pzcr  and altered basalt, diaba
Early Cretaceous? and Jurassic
Jpu
Serpentinized peridotite and dunite
JMu
Mafic and ultramafic rocks, undivided
Massive and layered gabbro, leucogabbro, harzburgite, garnet amphibolite, serpentinized peridotite, and dunite
Js
Serpentinite
Numerous small highly sheared and tectonically emplaced(?) bodies of serpentinite, also a large mass of serpentinite at Asbestos Mtn in the Cosmos Hills, and a large mass of partially serpentinized peridotite and dunite in the Jade Mtns.
s
Green and black serpentinite of unknown age or source associated with melange of unit MzPzm (Most of unit on map, associated with unit KJm, assigned NSACLASS of 5190)
Serpentinite, diabase-gabbro and some metadiorite and magnetite-rich
Green and black serpentinite of unknown age or source associated with melange of unit KJm  (Single polygon associated with unit MzPzm assigned NSACLASS of 5150
Pzsr
Schistose rocks
middle Paleozoic?
Chiefly white, light- to medium-gray, silvery gray, and brownish gray, fine- to coarse-grained quartz-mica-garnet schist.  Unit apparently conformable with unit Pzl, but contact is poorly exposed.
MzPzrc
Schist of Ruby and Garnet Creeks area
Paleozoic?
Polymetamorphic staurolite-garnet-schist containing subordinate quartzite, and hornblende amphibolite
Metabasaltic rock of unknown age, not as a separate mappable unit(?), but of significant size within other units to warrant distinction on the map.  In DOb and KJm. Polygons within unit MzPzm assigned NSACLASS of 5140
MzPzma
Metabasite.  Arctic Alaska Terrane
Varies from thinly layered greenschist to more massively layered greenstone bodies representing altered mafic and intermediate volcanic and  shallow intrusive rocks. The characteristic minerals are chlorite, albite, actinolite, and epidote.  Unit may inc
Metabasite
Mesozoic/Paleozoic
Mesozoic or Paleozoic
PzZm
Paleozoic and Proterozoic?
Green to dark-greenish-gray, thinly layered greenschist and more massively layered greenstone
MzPzmr
Massive greenstone to thinly layered greenschist bodies that probably represent metamorphosed mafic to ultramafic intrusive rocks and mafic to intermediate flows and tuffs.  Unit  is intercalated with with units PzZsr, Pzcr, and Dgnr
Mesozoic? to Proterozoic?
Massive greenstone to thinly layered greenschist bodies that probably represent metamorphosed mafic to ultramafic intrusive rocks and mafic to intermediate flows and tuffs.  Unit  is intercalated with with units PzZsr, Pzcr, and Dgnr.
Dark-greenish gray altered basalt and diabase; commonly altered or partially altered to aggregate of chlorite, epidote, and sodic plagioclase.  Separated from rest of unit; occurs only in southwest part of quadrangle.
Metamorphosed igneous rocks
post - Carboniferous
Greenstone, and locally some gray to red chert, dark-gray crystalline limestone, greenstone, tuff, and graywacke.  Greenstone is altered basalt and diabase of probable extrusive origin and diorite, diabase, gabbro, and pyroxenite of probable intrusive or
MzPmi
MzPzi
Intrusive rocks of intermediate to mafic composition
Light- to medium-green, massive, semischistose, fine- to medium-grained, inequigranular, locally porphyroblastic, metadiorite and metagabbro with relict igneous textures.
MzPzb
Altered basalt and diabase
Mesozoic (?) and Paleozoic (?)
Variably altered and metamorphosed dark-green to gray basalt and diabase.  Angayucham (?) terrane
Similar assemblage of rocks in Holy Cross and  Russian Mission quads have conodont, radiolarian, coral, and molluscan faunas of Carboniferous age.
Pzm
Metamorphosed mafic igneous rocks, ranging from metagabbro and metadiabase to greenstone, amphibolite, and garnet amphibolite. (Shown on source map compilation as unit Pzg)
Pzrmi
MzPzfm
Metabasic and metafelsic volcanic rocks, undifferentiated.
Dav
Pzd
Dolostone
Very pale-orange to moderate-reddish-brown, creamy weathering, very fine-grained, slightly calcitic dolostone, locally laminated.
Pzbs
Black shale and carbonate rocks
Dark gray to black siliceous and calcareous shale, with intercalated meter scale lenses of white- to tan-weathering gray limestone or dolostone, and lenses of light green volcaniclastic rocks.
DOsl
Shaly limestone
Ordovician to Middle Devonian
Dark-gray to grayish-orange finely laminated limestone and dolomitic limestone.  Suborbinate laminated dolomite, dark chert, and silicous siltstone.  Interpreted as deep-water facies of Osl, Od, and DSl carbonate units.  Now named East Fork Hills Formati
Conodonts
DCd
Pzl
Limestone and schist -- Limestone and dolomite
middle Paleozoic
Chiefly light-gray, massively bedded recrystallized limestone and dolomite, containing subordnate calcareous mica schist and dark phyllite
Tentatively assigned middle Paleozoic age based on correlation with fossiliferous carbonate rocks in the Solomon quadrangle
Pzls
Pzc
Carbonate rocks
Early Paleozoic
Limestone
Light-gray, recrystallized, limestone and dolomite containing minor intercalated phyllite and mica schist. Seward terrane, southwest part of quadrangle
Pzld
Limestone and schist
Undivided limestone and schist in areas of poor exposure
Pzls1
Pzu
Carbonate rocks and schist
Undivided carbonate rocks and schist in areas of poor exposure
PzZu
Schist and phyllite
Chiefly light- to dark-gray fine-grained quartz-mica schist and grayish-black phyllite.  Subordinate calcareous schist, limestone, chlorite schist, and amphibolite schist.  May locally include metasedimentary rocks of middle Cretaceous age.  Subdivison a
Pzpq
Pzs
Limestone and schist -- Quartz-mica schist, mica schist, and quartzite
Quartz-mica schist, mica schist, and quartzite.  Locally includes calcareous, graphitic, and feldspathic schists, amphibolite schist, phyllite, and thin limestone.  Age and stratigraphic relationship with unit Pzl uncertain, contact may be gradational.
PzZls
Pelitic schist, calc schist, and quartzite
Quartz-muscovite-graphite schist, calc schist, quartzofeldspathic schist, phyllite, and quartzite.  Unit is locally interlayered with unit Pzcs and is therefore, at least in part, Paleozoic in age.  Some of the unit may be as old as Proterozoic.
Samples of the schist yielded a metamorphic mineral K/Ar isotopic cooling age of 124 Ma
Dl
Devonian
Dark-gray, partly recrystallized limestone carrying light-colored, crushed crinoid columns, and  associated slate, shale, and fine-grained arkose.  No longer on map, lumped in unit JMtu
light-colored, crushed crinoid columns
Ds
Small masses of white to light-gray coarsely crystalline dolomitic and calcareous marble.  Locally altered to calc-silicate hornfels
Pzrm
mcl
Metamorphic complex
Precambrian or Paleozoic
Recystallized limestone - superceded, see source NL003
MDl
Mississippian to Devonian
Carbonates
PaMcl
Limestone and sandstone
Mississippian
Lenticular beds of fossiliferous limestone having subordinate beds of sandy limestone, chert grit, and arkosic sandstone.
Conodonts and foraminifera
Gray to white, partly to wholy recrystallized limestone, dark-gray dolomite, and impure schistose limestone.
see unit 7520 Od in Ruby or unit 5340, Ophir quadrangle.  Did not appear on final map.
Metalimestone and marble
Ml
Gray, bioclastic limestone, found in structurally isolated thrust slice  Not on OFR98-133
DSl
Dld
Limestone and dolomite
Latest Devonian (Famennian)
Light- to medium-gray or tan marker units of sandy, platy limestone and massive-bedded silicified limestone and dolostone having extensive locally developed boxwork silica.  Not on OFR98-133
Platy limestone and a limestone bed thought to be part of the section contains sparse conodonts of Famennian age.
Dlr
Limestone of Raven Ridge
Late Devonian?
Gray micritic limestone and brecciated limestone.
Undescribed megafossils
Pzmr
Distinctive marker bed of coarsely recrystallized marble within Pzsr unit
DSls
Ruby Marble
Paleozoic (?)
Medium- to coarse-grained marble composed of calcite with minor musovite, pyrite, and diopside (?).  Probably correlative with Tamarack Bluff limestone
Dm
Late Paleozoic or Devonian
Small masses of coarsely crystalline marble; local hornfels
Pzcr
Gray to white, partly to wholly recrystallized limestone, marble, dark-gray dolomitic marble, and impure schistose limestone.  Unit occurs in layers as much as 25m thick intercalated with quartz-mica schist, mica schist, graphitic schist, metabasite, and
Unit contains conodonts of Middle Ordovician age in the Nulato quadrangle and  poorly preserved corals of Ordovician to Late Mississippian age in the Ruby quadrangle
Unit contains conodonts of Middle Ordovician age in the Nulato quadrangle and  poorly preserved corals of Ordovician to Late Mississippian age in the Ruby quadrangle.
JPzu
Undifferentiated mafic volcanic rocks and phyllite
Jurassic and late Paleozoic and early Mesozoic
Mafic volcanic rocks (unit Jv) and dark phyllite (Pzp), undivided, in complex fault and intrusive relationships
Pzvs
MzPzr
Reindeer Hills complex
Thermally altered and metasomatized carbonate rocks, schist, and quartzite intruded by numerous small felsic and mafic bodies
Light-gray fine-grained recrystallized limestone; probably correlative with Skajit Limestone of Wiseman (Brosge and Reiser, 1960, 1964)
Partly recrystallized, reef-like limestone and dolomite
Mississippian or Devonian?
Chiefly light-gray, partly recrystallized, reef-like limestone and dolomite containing minor intercalated phyllite and schist.  Isolated masses resemble Lisburne Group and may be of Mississippian age.
Corals and stromatoporoids of probable Devonian age locally abundant.
Light-gray, recrystallized, limestone and dolomite containing minor intercalated phyllite and mica schist.  Arctic Alaska terrane, northern part of quadrangle
Pzkm
Marble of Klery Creek
White-weathering, medium- to light-gray marble having subordinate intercalated gray to green quartz-chlorite schist, black carbonaceous quartzite, and tan calcareous mica schist.
Early Devonian to Late Silurian conodonts and earliest Mississippian conodonts
White to gray, fine to coarsely crystalline, massive to platy marble and subordinate light-gray, finely crystalline dolostone.
Pzca
Ranges from light gray to white partly recrystallized limestone to coarsely crystalline marble. Dark finely crystalline dolomitic marble.  Interbedded calc schist, chloritic schist, and quartzite in subordinate amounts.  Unit ranges in age from Ordovicia
Contains scattered fossils, chiefly conodonts, from map area and from exposures of the unit in contiguous parts of the Arctic Alaska terrane north of the map area
Ranges from light gray to white partly recrystallized limestone  to coarsely crystalline marble. Dark finely crystalline dolomitic marble.  Interbedded calc schist, chloritic schist, and quartzite in subordinate amounts.  Unit ranges in age from Ordovici
PzpCq
Quartzite
Paleozoic or Precambrian
Fine-grained, light-gray quartzite and micaceous quartzite with subordinate quartz-mica schist, marble, and calc-silicate rock.  Stratigraphic relationship to PzpCs uncertain.
PzZrpg
TrMq
Quartzite, phyllite, limestone
Interbedded white to light-gray banded quartzite, dark phyllite, and gray laminated limestone forming two klippen overlying Ruby terrane rocks in the Kaiyuh Mountains
Pzrp
Ruby Phyllite
Graphitic phyllite with minor interbedded graphitic quartzite and quartzite.  Locally fine-grained graphitic schist and graphitic quartz-mica schist.  Hornfelsed when adjacent to TKg
TrMtqp
MzPzq
Quartzite-metachert, carbonate rocks, phyllite
Mesozoic? and Paleozoic?
PzpCs
Schistose metamorphic rocks
Early Paleozoic or Late Precambrian
Schistose metamorphic rocks -- Unit on northern edge of map recorrelated based on information from Bill Patton
Interbedded white to light-gray banded quartzite, dark phyllite, and gray laminated limestone. Thin sections show the quartzite to be composed of as much as 99 percent interlocking quartz grains.  Thin layers of white mica folia give the quartzite a fain
In the Nulato quadrangle the limestone is partly recrystallyzed and silicified and locally contains unidentifiable coral and crinoid fragments.  In the Melozitna quadrangle, thin marble beds contain conodonts and crinoids of Devonian age
Paleozoic to Mesozoic
Quartzite (metachert), carbonate rocks, and phyllite
Mesozoic? and Paleozoic
In the Nulato quadrangle the limestone is partly recrystallyzed and silicified and locally contains unidentifiable coral and crinoid fragments.  In the Melozitna quadrangle, thin marble beds contain conodonts and crinoids of Devonian age (Harris, written
Dp
Phyllite
Devonian (?)
Locally calcareous and chloritic phyllite; age based on correlation with similar rocks in Wiseman and Chandalar quads (Brosge and Reiser, 1964).  Unit subdivided by Patton.
Pzp
Pzpa
Metagraywacke and phyllite with chert interlayers and metagabbro dikes.  Unit MzPzs of Dillon and others (1986) subdivided by Patton (2000, written communication) into Pzg, graywacke and Pzp, Phyllite and subordinate metagraywacke.
Phyllite.
Dark phyllite and minor metagraywacke that have a penetrative fabric ranging from slaty cleavage to weakly schistose.  Unit locally contains slices of little deformed shallow-water Devonian carbonate rocks that are enveloped in basalt flows and debris-fl
Dark-gray to black phyllite with subordinate fine-grained metagraywacke
Phyllite and subordinate metagraywacke
Paleozoic(?)
PzPr
Phyllite and subordinate fine-grained metagraywacke cut by abundant vein quartz. The phyllite and metagraywacke are overprinted by a low-grade penetrative metamorphic fabric, but turbidite features, such as sole marks and graded bedding, are locally disc
Pzg
Dark-greenish-gray fine-grained impure graywacke.  In Wiseman quad.
Metagraywacke
Metagraywacke and phyllite with chert interlayers and metagabbro dikes.  Unit MzPzs of Dillon and others (1986) subdivided by Patton (2000, written communication) into Pzg, Metagraywacke and subordinate phyllite and Pzpa, phyllite.
Fine- to medium-grained metagraywacke and metasiltstone  composed chiefly of quartz and chert clasts, but in places containing a significant component of volcanic rock and feldspar clasts.  Overprinted by low-grade penetrative metamorphic fabric, but tur
Metagraywacke and subordinate phyllite
Fine- to medium-grained metagraywacke and metasiltstone composed chiefly of quartz and chert clasts, but in places containing a significant component of volcanic rock and feldspar clasts.  Overprinted by low-grade penetrative metamorphic fabric, but turb
Pzar
Argillaceous rocks
Permian or Middle to Late Devonian
Thin-bedded siltstone, slate, and phyllite, thick-bedded argillite, and minor laminated sandstone.  Metamorphosed to low grade.  Not on published OFR98-133
PDms
Sandstone, sandy limestone, and conglomerate
Fine- to coarse-grained yellowish-orange-weathering sandstone, limy sandstone, siltstone, and conglomerate.
Kuvelousia, Spiriferella, Waagenoconcha
Sandstone, sandy limestone and conglomerate
Graywacke, conglomerate and mudstone
Fine- to medium-grained graywacke, graywacke conglomerate with basalt, andesite, shale, chert, quartzite, and schist clasts, and green to gray mudstone.  Possibly correlative to graywacke of Rampart Group.
microfossils of probable Permian age
Pig
Graywacke, conglomerate, and mudstone
Fine- to medium-grained graywacke, graywacke conglomerate with basalt, andesite, shale, chert, quartzite, and schist clasts, and green to gray mudstone.
Contains microfossils of probable Permian age
Chert and argillite
Chert and argillite with interbedded rhyolitic tuff, sandstone, and grit.
Fragmentary fossil imprint identified as small immature ammonite of Cretaceous or Jurassic type.
TrDc
Triassic? to Devonian
Varicolored radiolarian chert, lenticular beds of fossiliferous limestone and interbedded argillite.  Subordinate beds of sandy limestone, grit, and arkosic sandstone.
Unit contains abundant radiolaria, condonts, and foraminifera that range in age from latest Devonian to possibly as young as Triassic
PaMc
Chert and limestone
Pennsylvanian and Mississippian
Chiefly greenish-gray, dark-gray to black, and red radiolarian chert.
Radiolarians
MDc
Late(?) Mississippian and very latest Devonian
Medium-dark to dark-gray, thin-banded, bedded, radiolarian-bearing chert containing thin interbeds of slaty argillite.  (See unit 6080 in MD quadrangle, correlated in part.).  Mapped as Kca by Cass (1959)
Chert and Slate
Mississippian and Devonian
Thin-banded grey, green, and red chert with thin interbeds of slate
Chert contains radiolarians of Devonian, Mississippian(?), and Mississippian age
Medium- to dark-gray, green, and some red radiolarian chert. interbedded dark-gray argillite, and very minor tuffaceous volcanic rocks
Chert, argillite, and limestone
Unit contains abundant radiolaria, condonts, and foraminifera that range in age from latest Devonian to possibly as young as Triassic.
Dao
Augen orthogneiss
Augen most commonly of white potassium feldspar, range in size from 1 to 10 cm long, most about 4 cm long.  Biotite is scarce to abundant.  Foliation layers containing biotite bend around augen.
MDrao
Augen orthogniess
Gnessic phase in southern part of the Melozitna pluton now recognized as augen orthogneiss.
MZ003
Dgnr
Granitic gneiss
Strongly foliated quartzofeldspathic gneiss.  Consists of a coarse- to medium-grained porphyroclastic biotite-quartz-feldsparñmuscovite mylonite gneiss containing resistant augen of K-feldspar in a ductile matrix of mica, quartz, and feldspar.
A U/Pb zircon determination from unit in the Tanana quadrangle yielded  a crystallization  age of 390 Ma, which suggests that it is approximately the same age as unit Dgna in the Arctic Alaska terrane.
Kg1
Chiefly leucocratic, medium-grained gniessic muscovite-biotite albite granite in Cosmos Hills
MDaao
Dgna
Gneissic granite
Foliated gneissic granite composed of albite, potassium feldspar, quartz, muscovite, and biotite.  Intruded by aplite dikes.
Pluton yielded a probable Devonian U/Pb zircon crystallization age.  Correlative in age with unit Dgnr in the Ruby terrane.
Mq
Globe quartzite
Vitreous quartzite associated with gabbro sills and dikes.  Light-gray quartzite.  Massive or thinly interbedded quartzite and medium- to dark-gray slate, phyllite, and minor laminated claystone.  Age from date of Trm intrusive and lithologic and stratig
Mg
Sls
Thin-bedded limestone
Silurian (latest Llandoverian to early Wenlockian)
Dark-gray to black platy limestone and limy shale.
graptolites
DSp
Paradise Fork Formation
Early Devonian and Silurian
Deep-water turbiditic and hemipelagic deposits of dark, thin-bedded, fissile to laminated limestone, limy shale, and siltstone.  The formation has an abundant graptolite, conodont, and ostracod fauna.  It was originally assigned an Early to Late Silurian
pCa
Amy Creek unit of Weber and others (1992)
Late Proterozoic? to early Cambrian?, Devonian?
White, massive, locally laminated, unfossiliferous cherty dolostone characterized by replacement silica boxwork locally and gray limestone at top and bottom of section.  Possible other correlations suggest this unit is equivalent to unit Dld of this quad
SZa
Ordovician or Silurian
Partly altered mafic lava and tuff, slate, slaty shale, phyllite, tuffaceous limestone, cherty schist, and chert.  Not on OFR98-133
Dt
Calcareous clastic rocks
early Paleozoic, possibly Devonian
Medium-gray siltstone and very fine-grained sandstone, largely calcareous and generally schistose.  Not on OFR98-133
Dq?
Pzw
Quartz wacke
Poorly sorted sandstone, granule conglomerate, siltstone, and semischist.  Not on OFR98-133
Dq2?
Limestone, dolomite, greenstone, and schist
Silurian or Devonian
Limestone, dolomitic limestone, partly silicified dolomite, basaltic greenstone, and chloritic schist.  Similar to unit Pzl south of Yukon River.
DSls?
Reefy limestone and dolomite
Late Silurian, Early Devonian (Siegenian-Emsian), early Late Devonian (Frasnian)
Unit composed of a lower sequence of dolomite containing ostracodes of probable Late Silurian age, a middle sequence of mixed limestone and dolomite having favostid reefs and shelly fossils of probable Early Devonian age and an upper sequence of Amphipor
ostracodes, favostid, Ampihpora, Smithiphyllum
DSwc
DSw
Whirlwind Creek Formation
Silurian to Devonian
Shallow water deposits consisting of several repeated cycles.  In the lower part of the formation the cycles grade from algal laminated dolomite into pelletoidal limestone and then into silty limestone and siltstone.  In the upper part  the cycles grade
The formation contains an abundant Late Silurian and Devonian  conodont, brachiopod, coral, and ostracod fauna.
Limestone, greenstone, and schist
Ordovician(?), Silurian, and Devonian
Dominantly light- to light-medium-gray partly dolomitic limestone and dolomite.  Basaltic greenstone and partly calcareous chloritic schist are associated sequentially or interbedded with the carbonate rocks
DSt?
Df
Felsic schist
Schistose felsic volcanic rocks, including flows, tuffs, and porphyritic hypabyssal? rocks, interlayered with metasedimentary rocks belonging to units  |<sa and |ca.  An important component of this unit is the widely recognized "button schist" -a porphyr
Unit yielded Devonian U/Pb and Pb/Pb zircon crystallization ages and is interlayered with carbonate rocks containing fossils of probable middle Paleozoic age.
Davf
Dcs
Calcareous schist
Light-brown weathering calcareous schist interbedded with gray quartz-mica schist and marble.  Brooks Range schist belt.
Pzsb
DOtu
Metasedimentary and metavolcanic rocks of Tukpahlearik Creek, undivided
Devonian to Ordovician
Black carbonaceous quartzite and silicieous argillite with lenses of dolostone and marble, silvery gray to silvery green pelitic schist, gray chert pebble metaconglomerate, green calc-schist, micaceous marble, dark green mafic metavolcanic rocks, gray or
Ordovician conodonts and Devonian to Ordovician conodonts
Black carbonaceous quartzite and siliceous argillite with lenses of dolostone and marble, silvery gray to silvery green pelitic schist, gray chert pebble metaconglomerate, green calc-schist, orange-weathering micaceous marble, dark green mafic metavolcan
Devonian to Ordovician conodonts
DOtq
Carbonaceous quartzite and quartz conglomerate of Tukpahlearik Creek
Devonian(?) to Ordovician
Black carbonaceous quartzite, gray chert pebble metaconglomerate, and quartz schist with minor intercalated lenses of gray marble, micaceous marble, dolostone, and grey quartz mica schist.  May be correlative with Pzbq.
Ordovician conodonts
DOtmq
Marble and quartz schist of Tukpuhlearik Creek
Greenish gray, gray, or green, fine- to medium-grained chloritic quartz schists and siliceous chlorite schists.
DOtpg
Pelitic schist and greenstone of Tukpaklearik Creek
Green and gray pelitic schists identical to the schist of unit DOtp with intercalated masses of dark green metabasite, mafic dikes, mafic extrusive rocks and white metachert.
DOtp
Pelitic schists of Tukpaklearik Creek
Greenish-gray, green, or gray fine- to medium-grained chloritic quartz schist and siliceous chlorite schist
Ol
Ordovician
Dark-gray limestone and brownish-yellow dolomite. Dolomite is common near base of section.   Lies unconformably on older metamorphic rocks.  Massive unit overlain by thinner bedded limestone and dolomite, succeeded by the thickest beds of the series.  To
Ont
Od
Massive dolomite and limestone
Middle to Late Ordovician (White Rockian to Maysvillian)
Light-brown to dark-gray massive dolomite and limestone cyclically interbedded with shallow-water yellowish-orange-weathering algal and lime mudstone.
Gastropods, corals, brachiopods, ostracodes, conodonts
Osl
Silty limestone and siltstone
Early Ordovician
Chiefly yellowish-orange-weathering, thin-bedded, shallow-water, silty limestone and limy siltstone.
Conodonts, trilobites, gastropods, cephalopods
Novi Mountain and Telstina Formations
Novi Mountain Formation: Shallow water deposits.  Predominately calcareous siltstone and shale in lower part.  Upper part characterized by cycles beginning with massive limestone commonly containing flat carbonate pebbles at the base and grading upward t
The Novi Mountain Formation contains a sparse Early Ordovician conodont fauna. The Telstina Formation contains an abundant conodont, brachiopod, and coral fauna.  It was  originally assigned a Middle and Late Ordovician age by Dutro and Patton (1982), bu
Novi Mountain and Telsitna Formations, undivided
[Novi Mountain Formation] contains a sparse Early Ordovician conodont fauna. The upper part [of Telsitna Formation] locally is characterized by platy dark limestone containing conodonts indicative of deep-water deposition.  The formation contains an abun
Chert and phyllite
early Paleozoic
Banded light-gray to black sooty impure radiolarian chert, green talcy phyllite and slate, thin-bedded shaly limestone, and calcareous quartzite.
SCpl
Oc
Banded light-gray to black sooty impure radiolarian chert, green talcy phyllite and slate, thin-bedded shaly limestone, and calcareous quartzite.  Reassignment of rocks originally assigned to unit Pzc in the Minchumina terrane to unit Oc
Unit locally contains conodonts and graptolites of Early and Middle Ordovician age in the Medfra quadrangle and east of the map area in adjoining parts of the Mt. McKinley quadrangle
Banded chert, argillite, fine-grained thin-bedded limestone, and silty dolomite.  Beds separated by carbonaceous partings.  Unit interpreted to be a deep-water sequence composed of turbiditic and hemipelagic deposits.
Ofc
Fossil Creek Volcanic unit of Weber and others (1992)
Agglomeratic mafic volcanic rocks, volcaniclastic rocks, and assoiciated argillaceous sedimentary rocks
Chert
Late(?) Ordovician
Light- to medium-gray chert.
Och
Pzlc
Livengood Dome Chert?
Heterogeneous, low-grade, blastomylonitic assemblage of silicieous to cherty argillite, recrystallized chert, intermediate to mafic volcaniclastic rocks and greenstone, graywacke, grit, and oolitic limestone.  Resembles lower grade parts of unit Pzs in t
Olc
Livengood Dome Chert
Separate from Pzlc which was described as:  Heterogeneous, low-grade, blastomylonitic assemblage of silicieous to cherty argillite, recrystallized chert, intermediate to mafic volcaniclastic rocks and greenstone, graywacke, grit, and oolitic limestone.
Pzll
Distinctive marker bed of lime mudstone, locally characterized by coated ooids; is part of Livengood Dome Chert
Oldl
Quartzite, grit, and argillite
early Paleozoic or preCambrian
Fine- to coarse-grained quartzite, quartz grit, quartz-feldspar grit, and argillite grading upward in to very fine grained quartzite, argillite, calcareous argillite, phyllite, and chert.
CZw
Sheared and foliated quartz and quartz-feldspar grits and quartzite intercalated with quartz-muscovite-chlorite and quartz-muscovite-biotite schists.  Subordinate phyllite, thin limestone, and metachert.
276 Ma K-Ar muscovite and 421 Ma K-ar(?) hornblende on intrusion (?) to unit.
pCw
Wickersham unit of Weber and others (1992), undivided
Cambrian and or Late Proterozoic
Poorly sorted quartzite and grit, having abundant quartz and plagioclase clasts in a quartzofeldspathic-wacke matrix.
CZwa
Cal
Argillite, slate, quartzite and grit
probably Cambrian, possibly in part preCambrian
Medium- to dark-red or maroon, light- to medium-green and grayish-green, and medium-gray argillite and slate.  Light yellow-brown to light-gray quartzite and grit.  Not on OFR98-133
PzPi
Meta-intrusive rocks of intermediate composition
Paleozoic and (or) Proterozoic
White, light gray, or green and white, massive to gneissic, granitic to dioritic meta-intrusive rocks.
Muscovite K-Ar of 107 Ma, biotite K-Ar of 95.9 Ma, biotite K-Ar of 96 +/- 1.2 Ma
PzZi
Paleozoic? and Proterozoic
Granite, granodiorite, diorite, and gabbro that have  a slight to moderate gneissic fabric.  The northwesternmost of the two bodies is Proterozoic  and has yielded a U/Pb zircon crystallization  age of 705 Ma.   The southeasternmost body is of uncertain
mca
In eastern part of quad, metamorphic complex mapped as two units, mca and mcb.   The older unit, mca is composed of crystalline limestone and greenstone with some schist and phyllite. (Assigned to Ruby terrane.)
PzpCs/TrMc
Map shows questionable identification of unit. (Assigned to Ruby terrane.)
PzpCsq
Schist, quartzite, phyllite, and slate
early Paleozoic(?) and preCambrian(?)
Light- to medium-gray and silvery gray quartz-mica schist, light- to medium-gray quartzite, light- to dark-gray slate and phyllite.  Not on OFR98-133
Pelitic Schist
Precambrian and/or Paleozoic
Fine- to medium-grained graphitic quartz-muscovite +/- chlorite schist.  Minerology consistent with greenschist facies metamorphism. (Assigned to Ruby terrane.)
mcb
The younger unit, mcb, contains schist and quatzite with some crystalline limestone, slate, and greenstone.  Part of unit recorrelated (D.N. Bradley, USGS, pers commun., 1998)
Greenschist and quartz mica schist
Medium-gray to medium-green, medium- to coarse-grained, schistose, foliated, actinolite-chlorite-epidote greenschist and biotite-chlorite-albite-quartz schist. (Assigned to Ruby terrane.)
Sandstone, grit, and argillite -- some polygons in northeast part of map reassigned to unit PzpCph, per Bundtzen and others (1997). (Assigned to Ruby terrane.)
Pzqs-s
Schist
Stipple pattern added to Pzqs on Dovers map; nature of unit to be determined.  Low to  moderately high-grade, blastomylonitic, polymetamorphic assemblage of pelitic to quartzitic schist containing subordinate layers of quartzo-feldspathic schist, calc-sc
PzPs
Paleozoic and Proterozoic
Phyllite and subordinate fine-grained metagraywacke cut by abundant vein quartz.  The phyllite and metagraywacke are overprinted by a low-grade penetrative metamorphic fabric, but turbidite features, such as sole marks and graded bedding, are locally dis
Pzq
Gray massive quartzite with subordinate quartz-mica schist
PzpCku
Mixed schists of the Kallarichuk Hills, undivided
Silvery green and gray quartz-mica schist, brown calcareous schist, gray marble, and black quartzite.  Carbonaceous rocks compose 20 percent of unit, marble less than 1 percent.  Indicate blueschist metamorphism followed by retrograde greenschist facies
Mississippian to Silurian conodonts
Proterozoic U-Pb age on zircon from granodiorite intruding marble, and K-Ar cooling ages of 114 Ma on muscovite and 91.6 Ma on biotite.
PzZmc
PzZsa
Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albiteñglaucophane   assemblages. A
K/Ar isotopic analyses of the schist yielded Early Cretaceous metamorphic mineral cooling ages.
Schist and quartzite
K/Ar isotopic analyses of the schist yielded Early Cretaceous metamorphic mineral cooling ages
Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albite ñ glaucophane assemblages. A
Samples of the schist yielded a metamorphic mineral K/Ar isotopic cooling age of 124 Ma.
PzZs
Quartz-mica schist and lesser amounts of calc schist, quartzite, graphitic  schist, chlorite schist, and quarto-feldspathic schist. Polydeformed greenschist-blueschist-facies characterized by quartz-muscovite-chlorite-albiteñglaucophane assemblages. A re
Pelitic schist
Paleozoic and Precambrian (?)
Pelitic schist including quartz-mica schist, chlorite schist, quartzo-feldspathic schist, and subordinate quartzite; metamorphic grade range of lower greenschist to almandine-amphibolite facies; local hornfels
PzZsr
Dark phyllite and fine-grained quartz-mica schist
late Paleozoic and early Mesozoic or pre-Devonian
Chiefly dark phyllite and fine-grained quartz-mica schist.  Unit underlies, overlies and interfingers with limestone and dolomite (unit Pzl).  Upper part may be late Paleozoic and early Mesozoic and lowest part may be pre-Devonian in age
Chiefly light- to dark-gray fine-grained quartz-mica schist and grayish-black phyllite.  Subordinate calcareous schist, limestone, chlorite schist, and amphibolite schist.  May locally include metasedimentary rocks of middle Cretaceous age.
PzPku
Silvery green and gray quartz-mica schists, brown calcareous schists, gray marble and black quartzite.
conodonts
Zircon U-Pb age, K-Ar age of 91.6 +/- 1.5 Ma from biotite
PzPkc
Calcareous schist and marble of the Kallarichuk Hills
Tan to brown calcareous quartz-mica schist, gray quartz-albite-mica schist, black carbonaceous schist, and lenses of massive gray marble tens of meters thick.
Zircon U-Pb of 705 +/- 35 Ma
PzPcb
Carbonate rocks and metabasite
Orange- to light-gray-weathering, dark-to light-gray, fine- to medium-grained crystalline dolostone, metalimestone and marble, with subordinate intercalated calcareous quartzite, quartz-mica schist, green and silver phyllite, carbonate cobble metaconglom
Schist and carbonate rocks, undifferentiated
Pelitic schist, calc schist, and quartzite (PzZsa) and carbonate rocks (Pzca), undivided
PzZua
PzPks
Siliceous schist of the Kallarichuk Hills
Light silvery gray to silvery grayish green to dark green garnet-mica-quartz schists.
Muscovite  K-Ar of 116 +/- 2.5 Ma, glaucophane K-Ar of 767 Ma, actinolite K-Ar of 660 Ma and 632 Ma
Precambrian or Paleozoic ( may contain Ordovician and Devonian)
Crystalline limestone, may  include rocks of Ordovican or Devonian but generally is more recystallized than Ordovican or Devonian rocks and is associated with schists.
In the eastern part of quadrangle, the metamorphic complex mapped as two units, mca and mcb.   The younger unit, mcb, contains schist and quartzite with some crystalline limestone, slate, and greenstone.
YZnm
PzpCc
Calc-schist
Light to medium-gray calc-schist and thin-bedded schistose impure marble  White to light-gray, fine-grained massive sandy marble.  Subordinate quartz-mica schist.
YZnc
Pztbl
Tamarack Bluff Limestone
Marble and recrystallized limestone, dominantly fine- to coarse-grained calcitic marble, with some sedimentary structures preserved.  Probably correlative with Ruby Marble
In the eastern part of quadrangle, the metamorphic complex mapped as two units, mca and mcb.   The older unit, mca is composed of crystalline limestone and greenstone with some schist and phyllite.
Zc
Calc-schist, quartz-mica schist, and greenstone
Proterozoic
Calc-schist, thin bedded schistose impure marble, and fine-grained massive sandy marble.  Contains subordinate quartz-mica schist and small bodies of greenstone.  Unit underlies unit Ont and gradationally overlies unit Zs
mc
Schist, crystalline limestone, quartzite, greenstone, slate, and phyllite.  Areas of crystalline limestone mapped separately when possible as mcl.
Late Precambrian or  Early Paleozoic
Quartz-mica schist, quatzite-schist, mica schist, albite-chlorite schist, albite-mica schist, ottrelite-mica schist, glaucophane-mica schist, some phyllite, slate, sheared chert, and quartzite.  Unit superceded.
Consists cheifly of quartzite, quartz-mica schist, chlorite schist, and micaceous and graphitic quartzite.  also include unknown thicknesses of or poorly exposed fine-grained pelitic schist and phyllite.
Quartz-mica schist, chlorite schist, quartzofeldspathic schist, quartzite, and micaeous and graphitic schist.  Regionally metamorphosed to greenschist-facies, but also locally includes high-pressure greenschist-blueschist-facies (distinguished by the pre
Metamorphic minerals in this unit in the Nulato quadrangle yielded  K/Ar isotopic cooling ages of 134 and 136 Ma.
PzpCp
Chiefly pelitic and quartzose metasedimentary rocks of greenschist facies.  Light-gray micaceous quartzite and greenish quartz-chlorite-muscovite schist grading into dark-gray quartz-muscovite-biotite-garnet schist.  Subordinate calc schist and marble.
K-Ar mica ages from 274-514 Ma, correlatives as old as 921 Ma
YZns
Zs
Pelitic schist, quartzite, quartzo-feldspathic gneiss, and greenstone
Chiefly pelitic and quartzose metasedimentary rocks of greenschist metamorphic facies.  Micaeous quartzite and quartz-chlorite schist grade into quartz-muscovite-biotite-garnet     schist.  Subordinate calc schist and marble.  Unit locally includes small
Zircon fractions from two samples of metamorphosed quartz porphyry indicate a crystallization age of 1,265ñ50 Ma.  Metamorphic minerals from the schist yield K/Ar isotopic cooling ages that range from 921 to 296 Ma
Chiefly pelitic and quartzose metasedimentary rocks of greenschist metamorphic facies.  Micaeous quartzite and quartz-chlorite schist grade into quartz-muscovite-biotite-garnet schist.  Subordinate calc schist and marble.  Unit locally includes small bod
Zircon fractions from two samples of metamorphosed quartz porphyry indicate a crystallization age of 1,265ñ50 Ma.  Metamorphic minerals from the schist yield K/Ar isotopic cooling ages that range from 921 to 296 Ma.
PzpCv
Metavolcanic rocks
Tan, light-gray, pink, and green banded fine-grained felsic volcanic rocks having well-developed foliation.  Chiefly porphyry composed of large phenocrysts of embayed quartz and plagioclase in a very fine grained quartzo-feldspathic groundmass which has
YZnv
ira
Pre-Cretaceous
Granite, monzonite and diorite altered to augen gniess and mica schist.  Locally contains younger granitic dikes.
pCm
Meta-quartz diorite
middle Proterozoic?
Sheared metamorphosed porphyritic quartz diorite
K-Ar on biotite 921 +/- 25 Ma, mouscovite in border zone 663+/- 20 Ma
Ynqd
PzpCn
Gneiss and quartzite
Quartz-feldspar-biotite gneiss commonly garnetiferous and locally contains sillimanite.  Almandine-amphibolite facies metamorphism.  Some augen gneiss.  Gray coarse-grained quartzite with thin layers of biotite.  Subordinate quartz-mica schist, marble, a
PzpCqg?
Quartzofeldspathic orthogneiss
Late Proterozoic? and or Paleozoic?
Quartzofeldspathic orthogneiss, located only on west side of Ray Mountains pluton.
Zg
PzpCg
Gneissic rocks
Garnetiferous quartz-feldspar-biotite gneiss of almandine-amphibolite facies.  Also includes some quartzitic gneiss, amphibolitic gneiss, migmatite, small bodies of marble, and a few small bodies of granitic rock.
PzpCsg
Pelitic Schist and Gneiss
Medium- to coarse-grained quartz +/- muscovite +/- chlorite +/- biotite +/- grapphite +/- garnet +/- staurolite schist, quartzofeldspathic orthogneiss, and foliated greenstone.  Minerology consistent with amphibolite facies metamorphism
MzPkc
Gametiferous quartz-feldspar-biotite gneiss of almandine-amphibolite facies.  Also includes some quartzitic gneiss, amphibolitic gneiss, migmatite, small bodies of marble, and a few small bodies of granitic rock.
MzZkc
Pelitic schist and gneiss
Paleozoic and preCambrian
Medium- to coarse-grained quartz+/- muscovite +/- chlorite +/- biotite +/- graphite +/- garnet +/- staurolite schist, quartzofeldspathic orthogneiss, and foliated greenstone.  Probably amphibolite facies metamorphism.
Quartz-chlorite-muscovite schist and micaceous quartzite.  Greenschist facies metamorphism.  Subordinate micaceous quartzite and glaucophane-chlorite-muscovite schist.  Unit includes many small bodies of marble, greenstone and greenschist (believed to be
PzpCm
Metamorphic rocks
Paleozoic and preCambrian?
Low to  moderately high-grade, blastomylonitic, polymetamorphic assemblage of pelitic to quartzitic schist containing subordinate layers of quartzo-feldspathic schist, calc-schist, calc-sliciate gneiss, amphibolitic schist, quartzite, marble, and metacon
PzZtqs
Relatively pure quartzite units locally mappable and typically associated with mafic rocks (unit Pzm) and metalimestone and marble (unit Pzl).  (Shown on source map compilation as uncolored Pzqs)
Metamorphic rocks (Pelitic schist)
Pelitic schist, quartzite, and calcareous to dolomitic marble, generally of greenschist facies.