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LIST OF MAP UNITS

[Some unit exposures on the printed or plotted map are too small to distinguish the color for unit identification. These units
are labeled where possible, and unlabeled units are attributed in the database, available at_http:/pubs.usgs.gov/sim/2909/|

OVERLAP ASSEMBLAGES LITHOTECTONIC TERRANES

SEDIMENTARY ROCKS KOYUKUK TERRANE

Shoshonitic tuffs and lava flows (Early Cretaceous)

Surficial Deposits

Qf Floodplain and tidal flat deposits (Holocene)

>

SEDIMENTARY ROCKS

Granite and granodiorite (Early Cretaceous)
Granitic gneiss (Devonian)

Syenite, monzonite, and nepheline syenite (Early Cretaceous)
Phyllite and subordinate metagraywacke (Paleozoic?)

Nepheline syenite (Early Cretaceous)
Metagraywacke and subordinate phyllite (Paleozoic?)

[| Dettaic deposits—units Ks, Kms, and Kes
[____] Submarine fan deposits—Units Keg, Kevg, and Kvg
[GG] Marginal shelf and slope deposits—Units Kec,

Kve, Kqc, and Kme

~<. Margin of Yukon-Koyukuk Basin

OVERLAP ASSEMBLAGES

[> VOLCANIC AND HYPABYSSAL ROCKS_-§- ——————_

CORRELATION OF MAP UNITS

[See DESCRIPTION OF MAP UNITS in accompanying pamphlet for specific age assignments]

[—— _ PLUTONIC ROCKS. ——

Scientific Investigations Map 2909

Christmas Mtn.
(Ksm)
8

Late Cretaceous and early Tertiary—
Units TKg and TKm

| Late Cretaceous—Units Kgd and Ksm

| Early Cretaceous—Units Kgr, Ksy, and Knsy

| | Cretaceous?—Unit Kgu

Sheet 2 of 2

Pamphlet accompanies map

Kobuk-!

—_
SS

Koyukuk subbasin

Lower Yukon subbasin

Koyukuk voleanie are terrane

Kig | Tuff, volcanic graywacke, and mudstone (Early Cretaceous) ;
[——— Surficiat Deposits. ——
Actively drifting and recently stabilized dune fields (Holocene) REGEN) Spititic basalt and diabase (Early Cretaceous?) = 1 4 _
Qf | ois | Holocene
Qs | Eolian and water-laid sand and silt sheets and stabilized dune fields (Holocene and Pleistocene) Kv _ | Andesite and basalt lava flows and volcaniclastie rocks (Early Cretaceous) cua , 4
. Qs Gab F Pleistocene L QUATERNARY
Alluvial, colluvial, glacial, and windblown terrace and slope deposits, undivided (Holocene and Pleistocene) ‘Trondhjemite and tonalite (Late and Middle Jurassic) QTol
at
Glacial and glaciolacustrine deposits (Pleistocene and Pliocene?) [ MePaum | Mafic-ultramfic complexes (Mesozoic and Paleozoic?) 2 ° L Pliocene
1Tgr |
Quartz gravel deposits (Quaternary or Tertiary) JDv. MELANGE
[- Miocene
Mélange (Early Cretaceous? and i
Small deposits of nonmarine conglomerate, sandstone, shale, and coal (Tertiary) sea i lange (Early Cretaceous? and Jurassic) | L cenozorc
Pecr
- TERTIARY
YUKON-KOYUKUK BASIN ANGAYUCHAM-TOZITNA TERRANE =s L Oligocene
JDv | Altered basalt, gabbro, chert, argillaceous rocks, tuff, graywacke, and carbonate rocks (Jurassic to Devonian)
Deltaic deposits UNCONFORMITY ROCKS OF UNCERTAIN
Ks Fluvial and shallow marine sandstone and shale, undivided (Cretaceous MzP:q | Quartzite (metachert), carbonate rocks, and phyllite (Mesozoic? and Paleozoic) AFFINITIY L Eocene
[[]kins |] hatlow marin sandstone and shat (Cretaceous) INNOKO TERRANE |
[koe ] Volcanic graywacke and conglomerate (Early Cretaceous?) UNCONFORMITY Tad
Kes | Offshore calcareous sandstone, siltstone, and shale (Cretaceous) L Paleocene
submarine fn deposits JMc | Chert, cherty tuff, argillite, crystal-lithic tuff, volcanic breccia, and conglomerate (Jurassic? to Mississippian) ——_ wrow-koyukvk Basin. ———,__- KUSkoKWIM BASIN
Carbonate-clast graywacke and mudstone (Cretaceous) [ERMBEY) Pitow basalt, chert, and minor agglomerate (Lriassic? to Mississippian?) Submarine fan Marginal shelf and Kg) TKm
Deltaic deposits deposits slope deposits Late
Carbonate- and volcanic-clast graywacke and mudstone (Cretaceous) [iu | Graywacke, grit, and argillite (Triassic? to Mississippian?) [ 1 | 1 | [Cretaceous
K Ksu
Voleanic-clast graywacke and mudstone (Cretaceous) Chert, argillite, and limestone (Triassic? to Devonian) ks “s Keo | Kae J
Kes k~ Kss 2
Marginal shelf and slope deposits NIXON FORK TERRANE Kowa ‘vo Ke] Kmo | a.
Kee | Carbonate-clast conglomerate, sandstone, and shale (Cretaceous) [kas] Quartz-carbonate sandstone (Early Cretaceous) Kins UNCONFORMITY 0 L Early CRETACEOUS
LITHOTECTONIC TERRANES Cretaceous
Volcanic-clast conglomerate, sandstone, and shale (Cretaceous) [ts | Spiculite and sandy limestone (Late Triassic) KOYUKUK TERRANE MELANGE ANGAYUCHAM- INNOKO TERRANE NIXON FORK MINCHUMINA TERRANE 2 RUBY TERRANE SEWARD TERRANE ARCTIC ALASKA TERRANE |: MESOZOIC
Kig [_ koa_| TOZITNA TERRANE TERRANE
Quartz- and metagraywacke-clast conglomerate, sandstone, and shale (Cretaceous) [Ps | Sandstone, sandy limestone, and conglomerate (Permian)
kv
Kme | Mafic igneous-clast conglomerate, sandstone, and mudstone (Cretaceous) Whirlwind Creek Formation (Devonian and Late Silurian)
UNCONFORMITY J ate ana |
ate an
KUSKOKWIM BASIN Paradise Fork Formation (Early Devonian and Silurian) Jgt IDV [- Middle JURASSIC
[Ks] Fluvial and shallow-marine sandstone and conglomerate (Late Cretaceous) 2 2 _ .
Novi Mountain and Telsitna Formations, undivided (Ordovician) Peca 4
[ss ] Shallow-marine sandstone, siltstone, and shale (Late Cretaceous) Pecr is] L rrassic
[EIA] Metavotcanic rocks (Late Proterozoic) 2
Ksu | Shale, siltstone, and sandstone, undivided (Cretaceous) JMc 2 4 4
. a ore : UDv | MePeq 2 ?
Pc Cale schist, quartz-mica schist, and greenstone (Proterozoic) [-PERMIAN
VOLCANIC AND HYPABYSSAL ROCKS RDo MePkc [PENNSYLVANIAN
fee . Pelitic schist, quartzite, quartzo-feldspathic gneiss, and greenstone (Proterozoic) East Fork Telida Pry 2 7
[ato | Tholeiitic basalt cones and flows (Holocene? and Pleistocene) hd “4 pathie g s UNCONEORMITY Eat Fork we 2 pa , | snississipPLan
2 2
MINCHUMINA TERRANE ? a
Alkalic basalt cones and flows (Pleistocene) ‘CHU! 2 ? bsw : Lpevonran | paLEozoic
East Fork subterrane DSp ? 4
i i }-SILURIAN
Basalt flows (Pleistocene and Pliocene) East Fork Hills Formation (Devonian to Cambrian) Bee PePsr 4
Req
Ont PR L
Tb | Basalt flows (Oligocene) Telida subterrane m up PeBsa | PeBua _FORDovIcIAN
}-CAMBRIAN
h ili ici UNCONFORMITY
[7a ] Andesite and basalt lava flows and volcaniclastic rocks (Eocene and Paleocene) [GET rert and arztive (Ordovician J 4
2
ite, grit, argillite, -mica schist (early Paleozoic and P' ic? Le] ? ?
[14 ] Dacite and rhyolite lava flows, domes, and volcaniclastic rocks (Eocene and Paleocene) Quartzite, grit, argillite, and quartz-mica schist (early Paleozoic and Proterozoic?) 2
2 2 ? ?
RUBY TERRANE Pc ;
Tad | Andesite and basalt lava flows and volcaniclastic rocks (Ta) and dacite and rhyolite lava flows, domes, and a , > ; |_proreRozoic
yolcaniclastic rocks (Td), undivided (Eocene and Paleocene) MzEke | Complex of Kokrines Hills (Mesozoic to Proterozoic?) I<]
[thr | Rhyolite hypabyssal bodies (Eocene or Paleocene)
[Meer | Metabasite (Mesozoic? to Proterozoic?) Ps
Tt | Tuff and tuff breccia (Eocene or Paleocene)
[ Dane | Granitic gneiss (Devonian)
[tka | Andesite and basalt lava flows and volcaniclastic rocks (early Tertiary and Late Cretaceous) J
Pepr | Phyllite (Paleozoic?)
Dacite and rhyolite lava flows, domes, and volcaniclastic and hypabyssal rocks (early Tertiary and Late
Cretaceous) [Per | Carbonate rocks (Paleozoic)
[_Tkad | Andesite and basalt lava flows and volcaniclastic rocks (TKa) and dacite and rhyolite lava flows, domes, and oo ; ; ; >
volcaniclastic and hypabyssal rocks (TKd), undivided (early Tertiary and Late Cretaceous) Pelitic schist, cale schist, and quartzite (Paleozoic and Proterozoic?)
[Ki | Shallow intrusive rocks of silicic and intermediate composition (Tertiary and Late Cretaceous) SEWARD TERRANE
[ Tkve | Volcano-plutonic complexes (early Tertiary and Late Cretaceous) [ mere | Complex of the Reindeer Hills (Mesozoic to Proterozoic?) 159° _ 459° so:
. > - 162° 162°
[tic | Complexes of shallow intrusive rocks and altered Cretaceous sedimentary rocks of the Yukon-Koyukuk Basin, Metabasite (Mesozoic? to Proterozoic?) =
undivided (early Tertiary and Cretaceous) 67° 67° 67° w-boo
Krd Rhyolite, dacite, and trachyte lava flows and volcaniclastic rocks (Late Cretaceous) [ Pcs | Carbonate rocks (Paleozoic) az ~y Ss
Hotham Inlet yi Hotham Inlet Hotham Inlet d 7 — 7 - Y -~-4
PLUTONIC ROCKS PPss | Pelitic schist, calc schist, and quartzite (Paleozoic and Proterozoic?) Q \ 0 Se US ey oe
TON] Granite (Eocene or Paleocene) Q ‘ NII I
P.Pus | Pelitic schist, calc schist, and quartzite (P:2ss) and carbonate rocks (P:cs), undivided (Paleozoic and schscholts Bay NS Poy uehchotte Bay ‘bschacholte Bay ‘
TKg | Granite and granodiorite (early Tertiary and Late Cretaceous) Proterozoic?) 66° of 66°
TKm | Monzonite (early Tertiary and Late Cretaceous) ARCTIC ALASKA TERRANE “
Metabasite (Mesozoic? to Proterozoic?)
[kod _| Granodiorite and granite (Late Cretaceous)
Felsic schist (Devonian) EXPLANATION
[_ksm_| Syenite and monzonite (Late Cretaceous) Early Tertiary—Unit Tg ; ,
Metabasite (Mz2ma) and felsic schist (Df), undivided (Mesozoic? to Proterozoic?) EXPLANATION 65° || . EXPLANATION

Granitic rocks of uncertain affinity (Cretaceous?)
Carbonate rocks (Paleozoic)

Pelitic schist, cale schist, and quartzite (Paleozoic and Proterozoic)

Pelitic schist, cale schist, and quartzite (P:2sa) and carbonate rocks (P:ca), undivided (Paleozoic and
Proterozoic)
Granitic gneiss (Paleozoic? and Proterozoic)
ROCKS OF UNCERTAIN AFFINITY

Gabbro and diabase (Tertiary? to Devonian?)

2
Fy

159°

Baird Mountains (BM)] Ambler River (AR) 158°

Selawik (SL)

150° 159°

150°

162° 162°

Survey Pass (SP)

67° 67°

Hotham Inlet Hotham Inlet

Shungnak (SH) Hughes (HU)
Eschscholtz Bay

66°

Eschscholtz Bay

Tanana (TA)

Kateel River (KR)
Candle (CD) Melozitna (ML)

65°

EXPLANATION

| Koyukuk terrane

forton Bay (NB)

63°

67°

Hotham Inlet

Eschscholtz Bay

Nulato (NU) Ruby (RB) Margin of Yukon-Koyukuk Basin
— = — = Strike-slip fault—Half arrows indicate
64° direction of relative movement; dashed
where approximately located or uncertain
Unalakleet (UN) i *
inalakleet -
Ophir (OP) Medfra (MD)

63°

Index to 1:250,000-scale quadrangles and quadrangle abbreviations

63°

0 50

Figure 54. Map showing distribution of lithotectonic terranes: Koyukuk terrane.

100 KILOMETERS

64°

0 50

100 MILES

100 KILOMETERS

— — Strike-slip fault—Half arrows indicate
direction of relative movement; dashed
where approximately located or uncertain

Figure 2. Map showing distribution of middle and Late Cretaceous sedimentary rocks in and near the Yukon-Koyukuk Basin.

Figure 5B. Map showing distribution of lithotectonic terranes: Angayucham-Tozitna terrane.

oO 25 50

EXPLANATION

| Angayucham-Tozitna terrane

<7 "==. Margin of Yukon-Koyukuk Basin

— SS — — Strike-slip fault—Half arrows indicate

direction of relative movement; dashed
where approximately located or uncertain

100 MILES

50 100 KILOMETERS

Hotham Inlet

Eschscholtz Bay

100 MILES

0 50 100 KILOMETERS

Figure 3. Map showing distribution of plutonic rocks by age groups.

67°

66°

Margin of Yukon-Koyukuk Basin

Strike-slip fault—Half arrows indicate
direction of relative movement; dashed
where approximately located or uncertain

Innoko terrane

Nixon Fork terrane

Minchumina terrane

— = — — Strike-slip fault—Half arrows indicate

Margin of Yukon-Koyukuk Basin
direction of relative movement; dashed
where approximately located or uncertain

25 50 100 MILES

°

50 100 KILOMETERS

Figure SC. Map showing distribution of lithotectonic terranes: Innoko, Nixon Fork, and Minchumina terranes.

Geologic Map of the Yukon-Koyukuk Basin, Alaska

By

William W. Patton, Jr., Fredric H. Wilson, Keith A. Labay, and Nora Shew

2009

Hotham Inlet

Eschscholtz Bay

<7 =S. Margin

direct

100 MILES
100 KILOMETERS
Figure 4. Diagrammatic sketch of Yukon-Koyukuk Basin showing Kobuk-Koyukuk and lower

Yukon subbasins and Koyukuk volcanic arc terrane. The subbasins and the volcanic arc
terrane are dextrally offset 105 to 130 kilometers along the Kaltag Fault.

159°

Aretic Al

where

50

50

Figure 5D. Map showing distribution of ithotectonic terranes: Seward, Arctic Alaska, and Ruby terranes.

Any use of trade, firm, or

— SS — — Strike-slij

of Yukon-Koyukuk Basin

fault—Half arrows indicate
ion of relative movement; dashed

where approximately located or uncertain

EXPLANATION

Seward terrane

Jaska terrane

Ruby terrane

Margin of Yukon-Koyukuk Basin

Strike-slip fault—Half arrows indicate
direction of relative movement; dashed

approximately located or uncertain

100 MILES

100 KILOMETERS

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