Scientific Investigations Map 3131 U.S. Department of the Interior Sheet 2 of 2 U.S. Geological Survey Pamphlet accompanies map

167°20' 167°10' 167°00' LIST OF METAMORPHIC-TECTONIC ELEMENTS eclogite-facies assemblage; blueschist-facies assemblages are small metagabbro bodies are variable; some show weak Aluminous rock with assemblage that contains relicts Ot Qs Ol variably overprinted by facies assemblages greenschist-facies overprint, others show pervasive static of the reaction orthoamphibole + kyanite = cordierite + Ol Ol Ol Ol Ol Ols Ols York Terrane—Late Proterozoic (?) and Paleozoic sedimentary Nome Complex, west-central—Weakly foliated metasedimen- overgrowth of greenschist-facies over igneous garnet or staurolite (decrease in pressure) and metasedimentary rocks and minor Late Cretaceous tary and unfoliated metaigneous rocks that retain relict minerals; one contains pseudomorphs after blue amphibole Pelitic rock crystallized at temperatures above the second Qs Oal tin-bearing granites; dominantly carbonate and siliciclastic primary features; mineral assemblages in mafic rocks formed High grade metamorphic and associated igneous rocks— sillimanite isograd and aluminous rock with mineral Oal Ol 165°00' lithologies, in which primary features are generally retained; at pumpellyite-actinolite, greenschist, and blueschist facies Amphibolite and granulite-facies metamorphic rocks and assemblage that contains relicts of the reaction alumino- 17 Ol E Ol Ols fine-grained metasedimentary rocks are weakly foliated. (one locality) associated Cretaceous plutons; penetratively deformed silicate + orthoamphibole = cordierite + garnet or stauro- Op Ols Oal Qs Metamorphic and thermal history variable from unit to unit, Nome Complex, eastern—Penetratively deformed and metasedimentary and metaigneous and with lite (decrease in pressure) Ktg Ols Ol Cape Espenberg and generally lower grade than Nome Complex. Tin granites recrystallized with ductile fabrics; protolith packages complex metamorphic histories; aluminum-rich lithologies Pelitic rock crystallized at temperatures above the second Ol intruded in shallow crustal settings. The generally brittle and metamorphic fabrics identical to Nome Complex in show early development of kyanite-stable mineral assem- sillimanite isograd Ol Ol Oal Ol shallow and steeply-dipping structures in the area may have central ; mineral assemblages in most of the blages succeeded by sillimanite-stable, lower-pressure 65°30' Ol Kyanite Ol Ols Qs formed in shallow contractional settings, extensional settings, area are characteristic of greenschist facies, but slightly assemblages. Lithologies rich in iron and aluminum retain Ols higher grade assemblages occur in the vicinity of Kiwalik early, relatively high pressure aluminosilicate plus orthoam- SOul or both Andalusite Nome Complex—Late Proterozoic and Paleozoic metasedimen- Mountain. Lack of high pressure metamorphic minerals may phibole assemblages (>5kb) that are overprinted by relatively SOdl tary and metaigneous rocks, metamorphosed during the be significant or a product of poor exposure and limited lower pressure cordierite plus staurolite or garnet assem- Approximate position of second sillimanite isograd; teeth Ol Mesozoic sampling. Metamorphic history of this block may not be blages (<5kb). Timing of peak metamorphism and exhuma- towards higher-grade rocks E14 QTv Oal Oal Nome Complex, central—Penetratively deformed and recrys- consistent throughout and the block may be cut by unrecog- tion may not be the same in Kigluaik, Bendeleben, and Darby Ol Ol tallized schists with ductile fabrics; mineral assemblages nized faults mountain ranges. Kigluaik and Bendeleben ranges formed in CONODONT COLOR ALTERATION INDEX (CAI) VALUES Ol record a blueschist-facies event that traversed lawsonite- Nome Complex, northern—Weakly foliated metasedimentary the Tertiary and are bounded by active faults Ktg QTv Devil [See appendix, including tables A-1 and A-2 in pamphlet, for more informa- stable conditions and peaked at -stable conditions; one and unfoliated metaigneous rocks; mineral assemblages in Grantley Harbor fault zone—Weakly metamorphosed metasedi- Mountain tion] Ol Whitefish Lakes mentary rocks with stronger deformational fabrics than those Ols QTv Ol QTv Lake in the western Seward Peninsula, but weaker deformational Not determined Killeak Ol fabrics than the Nome Complex. Primary sedimentary Ols QTv Lakes 1.5–2.5 Oal features locally preserved QTv 162°00' Angayucham terrane—Mafic, ultramafic, and tonalitic rocks QTv Minimum 1.5–2.5 and maximum 3.0–3.5 65°25' juxtaposed along a series of vertical faults with minor slivers DOx Kv of Nome Complex carbonate rocks; mafic rocks are 3.0–3.5 volumetrically dominant, contain blueschist and albite- Ol uk R Nu gnugalukt iver Qs epidote-amphibolite facies metamorphic assemblages, and Minimum 1.5–2.5 and maximum 4.0–4.5 DOx exhibit weakly foliated to mylonitic fabrics Oal E S O U N D Conglomerate and sandstone—Unmetamorphosed Cretaceous Minimum 3.0–3.5 and maximum 4.0–4.5 S E B U erp T Z Ocs (?) carbonate-clast conglomerate and sandstone, likely related e iver O nti R K Kv 4.0–4.5 ne Kv to marine sedimentary rocks of the Yukon-Koyukuk basin; Kv Tertiary (?) sandstone and coal Cape Deceit Yukon-Koyukuk basin—Folded and faulted Mesozoic volcanic 5.0–5.5 d DObm *# and marine sedimentary rocks and associated plutons. QTv Oim Ksy Minimum 5.0–5.5 and maximum 6.0–6.5 66°00' Qs r Dks GF m Cenozoic volcanic rocks—Basalt cinder cones, flows, and large 168°00' ve i DObm Dks m DOx Kv R DObm maar volcanoes with associated pyroclastic rocks 6.0–6.5 pe m 66°00' ho m od d Kugruk fault zone Go DOx m Minimum 5.0–5.5 and maximum 7.0–8.0 m Kv QTv METAMORPHIC MINERAL KEY g Ocs Minimum 6.0–6.5 and maximum 7.0–8.0 Ol QTv Ksy # Lawsonite Ktg QTv QTv E DOx Oim Ddm 7.0–8.0 20,21 DOx Oim TKs Ksy TKv Pseudomorph after lawsonite Oim m DOx DOx E Od d QTv MAP SYMBOLS +$ QTv DOx Ocs 78 1 40 39 m QTv DOx Glaucophane K-Ar, Ar/ Ar, and Rb-Sr sample location; see table 2 for 80 m Oim l E Ktg DOx Oim TKs DOx age data Little Ddm E79 Glaucophane and pseudomorph after lawsonite 1 Kgu Diomede *# Ocs Kgu DOx " U-Pb zircon sample location; see table 3 for age data Ocs Island DOx Kv Ks Ddm m E GF Ksy Pseudomorph after glaucophane Qs GF DOx Mountain m 77 Od m Op Ol m Od Kv Pseudomorph after glaucophane and pseudomorph after Ds KsKEs 1:250,000-scale quadrangle boundary Op Ol DOx Jt lawsonite 75 DOx Ksy l Ds 15,16 QTv EE EKsK Kv Crossite or glaucophane Contact—Depositional, intrusive, or metamorphic, as shown on Oal 74 EKku E Kgu Fairway Op 65 E Ol gb DOx Oim 102 sheet 1 Rock Ol Ol Df Qs 1 Ds m QTv Kv Crossite or glaucophane and lawsonite Fault—Dotted where concealed, as shown on sheet 1 Ot Op Ol Ds 18,19 Oim EE Op Oim Ocs Ol QTv 73 Ds Eclogite Contact—Metamorphic-tectonic elements Ktg DOx E Ol Ol Ocs *# Ml Ot 2 m KsKs gb" Ol Ol Ol Ol Ol DSl Imuruk d Aluminous rock with mineral assemblage that contains relicts Major fault or tectonic subdivision boundary—Dashed where gb Ols Ktg Ols *# Lake 68,69,70 m of the reaction aluminosilicate + orthoamphibole = York DOx EEE QTv QTv concealed or approximately located Op 17 Oal Oim 71,72 Jt Ol Ol E Mountains EEEE Dg QTv cordierite + garnet or staurolite (decrease in pressure) Oal Ol Ol QTv m DOx Road gb Ols DOx Ocs m 66,67 Df Kv Ol SOul Ocs 19 d Ol Ol Ol Op " TKs DgKiwalik Op E*# Ddm Qlj Kbk TKs Jt 18 SOdl Ocs *#" Mountain Oal E Ols Ol 13 Op *# 76 Kgr 14 Ol E Ol r SOul gb Oal e 16 Ocs

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n T o k - Z p DOx e o 165°00' r DOx m m (! lt o a DOx u DOx N g u n t a i n s Ddm QTv u o m a Mm F o h Gran K e n r tley A DOx b Espenberg o H g Kgu l e 56 Devil b *# a i Kds ! E Maars r rb a e ( North a o p Qs d 17 Kbk m Mountain r u h n (! H " Oim GF*#GF Killeak p Ocs k e h (! m Kgu maar R h B Whitefish Devil maar y iv DOx le l e m Kv maarWhitefish Mountain t r «! (! DOx ¨ (! DOx K Lake Lakes Killeak n t «! (! ¨ h TKs oyuk R a iver Lakes r *#*# K g (!(! 14 (! hDeath Valley QTv u 52,53 " (! m *# G GF 4 zi r Kp GF m m 162°00' E e EEE m Kbk South E tr v Kgu Mount «!*# «! (!¨ in Ri h Kwc Ddm Cenozoic Killeak 3 51 Bendeleben «! «! DOx 44 Oim QTv E" Kwc 54h (!(! " volcanic maar np Kgu 50 h v (! 11 rocks E nE «! (! Ocs QTv TZEBUE SOUND Imuruk " «! " DOx GF KO 8 E 15 «! 12,13 DOx TKs Ocs Basin h Ocs GF DOx Kv QTv GF E McCarthys Marsh Kd 66°00' 168°00' 7 h Cenozoic Kg Kg DOx Cenozoic 65°00' DOx (! DOx Od DOx volcanic volcanic King Island h h Kg Ds TKs *# DOx d E E Qs (!(! 10 *# m m Ear Oonatut rocks rocks Cenozoic E o DOx " 6 2 65°00' Granite volcanic Cenozoic 5 Kg 47,48 49E (! E Sd Mountain Alkaline volcanic Kgu h 1 E Dcs Ocs 43 Complex rocks rocks Kg 55 EE 46 h m Oim DOx stock Felsic rocks Kds " o E 45 *# E «! E *# Crossfox volcanic Alkaline h 28 (! (! d DOx Asses hMount Ds DOx Ddm Little Butte rocks rocks o DOx stock Ears Kg Osborn Ocs s Diomede o 8 40 a i n s h 101 98 94 Kougarok Granitic rocks, t E n Dbm stock E"Kdi u n +$ (! DOx DOx E E d Island Qs o 5,6 E i TKs m m Mountain undifferentiated 9 Mh o " "E 39 m " hi k 37 38 n 100 *#Ocs DOx «! a Alkaline a t u 33 EE o Od Dcs Kd Fairway Virginia Kugruk gKgl EEEoEEE DOx«! d GF Butte Cenozoic rocks Kg i E30 Ocs Oim Kdc n m m Rock Cape Cenozoic pluton K 36 34 n 4 DOx Oim «! d stock volcanic h 31,32 35 h " Ds u Mountain Ocs 42 E $ Lake m E h +$ volcanic rocks E Kg E +$+ m +$ o Imuruk o 27 +$ DOx DOx 97 stock Brooks Black rocks 29 h *# *# m Qs Lake Creek Ocs M Mountain DOx Dcs m QTv Mountain Nimrod pluton *# Ds Ddm h Kds DOx Ocs (! Dbm stock stock Lost Jim Hill E 41 #E Kgu¨(!¨ y m Lost River # * 26 Oim 23 Basalt stock h * Oim b Tin Creek Ocs r (!(! GF Mines DOx e E" r N Dcs v *# stock Kuzitrin o Ds i (! 22 96 a m 7 *# *# R Ddm m e " " m pluton - Oim Dcs Ocs h

Mount D T *# DOx is Cenozoic d e (! TKs a Oim l Ds # # F o Granite Qs l DOx *# Ocs * DOx Arathlatuluk Ddm volcanic Alkaline e R Granitic rocks, 168°00' r Oim *# Ds 95 r Mountain rocks Moon R n Oim rocks l o undifferentiated o E y Ocs a Kds EE a pluton d DOx Grantl T Shaded relief from National Elevation Dataset (NED) 42.7-meter Digital Elevation Mountains DOx 99 Kds ey H - Dikes and ar e mm E 92,93 m bo Granitic rocks, E DOx E Ocs Ddm r m stocks Bendeleben Models (DEMs) o undifferentiated 25 91 Ddm E N pluton Universal Transverse Mercator Zone 3N; 1927 North American Datum Ocs r e Kds E DOx Oim 82 Windy iv 90 DsE Dcs Kkms m Creek Base layer for water from 1:250,000 quadrangles (1950–1955) R Ocs 89 Granitic rocks, k Imuruk u *# EE m undifferentiated pluton Cenozoic Cenozoic n Dcs Ocs Ocs Basin Si n Oim 87,88 Pargon volcanic " DOx Ocs m Y King volcanic DOx 3 DOx pluton rocks rocks *# Ddm Ddm A 65°00' Island Kigluaik B Darby DOx Ocs h pluton Dcs *#*# DOx Mount pluton DOx DOx E Kkms m N EE23,24 Ds 86 O Dry Arathlatuluk DOx Dcs Dbm T DOx Kkg R Dikes and Canyon Ocs DOx Ddm O stocks Salmon stock m N N Dikes and Darby DOxE ^_ Ddm o Lake Qs d DOx Qs Ocs 81 Kd m Granitic rocks, a E E stocks pluton o Dks e 22 Ds EE - Cenozoic undifferentiated R 85 T Dcs Ocs e Oim Ocs 83,84 h l l Kkgm e volcanic

r Ds R rocks o a Kkms cil d un Ds Dikes and Co e- NATIONAL GEODETIC VERTICAL DATUM OF 1929 Kgu ! m m stocks No Y BA Sledge Island Nome N Kachauik TO R n Kkd pluton O m h N d a " Ro Cape Nome 20,21 Ds cil Sledge un Co 162°00' Nome e- 159° Island om 168° 162° 67° N 165°

NORTON SOUND 10 0 10 20 30 40 Miles SHISHMAREF KOTZEBUE SELAWIK 162° 161° 160° 159° Geology compiled by Alison B. Till (2008) 66° GIS database and digital cartography by Keith A. Labay 10 0 10 20 30 40 50 Kilometers D-6 D-5 D-4 D-3 D-2 D-1 and Heather A. Bleick 66° Edited by Theresa Iki Figure 2. Map of the Seward Peninsula, , showing locations and names of Quaternary, Tertiary, and C-6 C-5 C-4 C-3 C-2 C-1 Cartography by Darlene A. Ryan Cretaceous igneous rocks. Cenozoic volcanic rocks, pale yellow; Late Cretaceous tin-bearing granites, dark CANDLE 65°30’ Manuscript approved for publication July 14, 2010 yellow; compositionally diverse Early and Late Cretaceous rocks, brownish red; Early Cretaceous alkalic rocks, TELLER BENDELEBEN 165°00' B-6 B-5 B-4 B-3 B-2 B-1 pale pink; dikes and stocks, magenta.

65° A-6 A-5 A-4 A-3 A-2 A-1 65° Tectonic, Metamorphic, and Geographic Data for the Seward Peninsula, Alaska NOME SOLOMON By 64° Any use of trade, product, or firm names in this publication is for descriptive 1 1 2 1 purposes only and does not imply endorsement by the U.S. Government. Alison B. Till , Julie A. Dumoulin , Melanie B. Werdon , and Heather A. Bleick For sale by U.S. Geological Survey, Information Services, Box 25286, INDEX MAP SHOWING 1:250,000-SCALE QUADRANGLE NAMES AND LABELS FOR Federal Center, Denver, CO, 80225, 1–888–ASK–USGS 1 2 1:63,360-SCALE QUADRANGLES WITHIN EACH 1:250,000-SCALE QUADRANGLE 2011 U.S. Geological Survey, Anchorage, Alaska, Alaska Division of Geological and Geophysical Surveys, Fairbanks, Alaska Digital files available at http://pubs.usgs.gov/sim/3131