The western Romanzof Mountains cover a remote 700-square-mile area in the Brooks Range, northeastern Alaska. The area is topographically rugged and geologically diverse; it contains a gramtlc pluton, low-grade metamorphic rocks, sedimentary rocks and mafic igneous rocks, as well as glacial features.Rocks of sedimentary origin, from o1dest to youngest are: l. Neruokpuk Formation (Precambrian, Cambrian, and pre-Mississippian), more than 4,000 feet thick, consists of units of the greenschist facies, including quartziticand schistose-feldspathic to quartzose graywacke; phyllite, argillite, slate; minor chert; and limestone. The succession of units in parts of the area is uncertain. Correlations of these units with each other and with other units in the eastern Brooks Range are provisional. 2. Katakturuk Dolomite (Devonian or older), silicified carbonate rocks, mostly dolomite, with minor dark shale, carbonate conglomerate and breccia beds, pisolite and oolite beds. Probably more than 1,000 feet thick. 3. Kekiktuk Conglomerate and Kayak(?) Shale (Mississippian), a single map unit, 0(?)-420 feet thick, contains quartzite, interbedded dark shale, and some pebbleto boulder-conglomerate in the locally absent lower part (Kekiktuk), and, in its uppermost part, dark shale (Kayak(?)). The unit overlies the Neruokpuk and Katakturuk with angular unconformity, which may reflect either a pre-Kayak(?) or pre-Kekiktuk hiatus or both. 4. Lisburne Group, almost entirely carbonate rocks, is 600-800 feet thick in the northern part of the area and probably 1,200 feet thick in the southern part. Alapah Limestone (Upper Mississippian) of this group, as much as 560 feet thick, includes gray sandy, crystalline, and cherty limestones; minor dark shale; and, in the upper part, dark cherty carbonate rocks. Dark shaly and cherty carbonate rocks abo constitute the lower part of the group in the southern part of the area. The lower contact is gradational with the Kayak(?) Shale. The Wahoo Limestone (Pennsylvanian) conformably overlies the Alapah, is 0-200+ feet thick, and is characterized by light-gray crinoidal limestones in its upper pan. 5. Sadlerochit Formation, consisting of two members: the Echooka Member (Upper Permian) of iron-stained orthoquartzite and dark slate, 175-240 feet thick, which unconformably overlies the Wahoo and Alapah Limestones; and the Ivishak Member (Lower Triassic), consisting of a shale unit of dark shale, slate, and minor quartzite averaging 400 feet in thickness, and a quartzite unit, 700 feet thick, mostly orthoquartzite with minor shale and conglomerate. The basal clastics were probably shed from the north. 6. Shublik Formation (Middle and Upper Triassic), 60Q-700 feet thick, the thin phosphatic sandstone member is overlain by dark phosphatic limestones and limy shales of the limestone member.

The Romanzof Mountains comprise a high, rugged mountain group in the northeastern Brooks Range. A granite b o w of small batholith size, the "akpilaka granite, occupies the 1 central part of the Romanzofe, and is flanked by sedlmentarp D and metasedimentary rocks which range from pre-~ssisslpplan 1 t to Jurassic in age. Pllaflc dikes and extrusive(?) rocks are of minor occurrence. cretaceous(?) rocks are exposed north of the area. The Neruokpuk formation of pre-Mlssissipplan age l a here mapped to lnclude several sedhentary and low grademetasedlmentary rock units. These lnclude a loner black limestone unit overlain by Interbedded limestones, phyllite, argillite, alate, chert, and quartzite, In turn overlain by a thick section of quartzite and schlstoee quartzite. The total thickness of the Nemokpuk sequence I s believed to be more than 4400 feet, A major angular unconformlty separates these rocks from the overlying Mississippian rocks.. Mlssiaelppian rocks lnclude the Kayak "shalea, a unit of light to dark gray.quartzite, carbonaceous shale, and conglomerate which Is 0 to about 400 feet thick. The Llsburne group, of late ~Mssissippian age, consists of gr& limestone and dolomite, with minor amounts o f chert, black shale, and sandstone, and is as much as 780 feet thick. The .group la overlain at least disconformably by Permian rocks. The Sadlerochlt formation, of ~ermlan-Triassic(?) age Includes a lower Ferruginous sandstone member, about 200 only known granitic body on the northern side of the Brooks Range. In addition, a variety of sedimentary and metamorphic rocks are present, and Pleletocene to Recent valley glaciation features are abundant. Qeologic field Investigatlons were undertaken during the summers of 1957 and 1958 to study the granite and its relationsNpa to addoinlng rocks and to compare the sedimentary and metamorphic rock sequence wlth those in bebter known areas of the Brooke Fbnge. Location,-Size, and Accessibility-of Area The Romanzof Mountains lie within the Mount ?'Kchclson and Demarcation Point Quadrangles, Alaaka, and cover about 600 square miles. They are approximately bounded on the east and west by the Jago and Hulahula Rivera, respectively, and lie between latitudes 6 9 ' 0 5 ' and 6g02j" N (~i g u r e 1). Airline distances to the nearest Alaskan settlements of Barter Island, Bettles, and Barrow are 60, 130, and 320 miles reapectively. No roads or established tralls are present Into or within the area, and access ts most easily accomplished by use of small float-or ski-equipped aircraft. Within the area, travel can beat be accomplished on foot. Although tracked vehlcle travel 1s possible along the Jago, Ckpllak, and Ifulahula Rivera nearly to their headwaters, such travel would be dlificult within the mountains. Shall&

Undiscovered Recoverable Oil 36-81 Billion Barrels Undiscovered Recoverable Gas l §~ .. 5)~~ Trillion Cu Ft * Marginal Probability Applied * * For regional distribution of inferred reserves. see tables 4 and 15. FIGURE !.-Undiscovered recoverable resources of crude oil and natural gas for the United States. Report~ as a range of values at 95-5 percent probability in billions of barrels for oil and trillions of cubic feet for gas.

Features related to climate.______________________ Permafrost. ________________________________ Ground ice_______________________________ Microrelief features-________________________ Stratigraphy_______________________________________ Jurassic (?) and Cretaceous systems ______________ Siltstone and shale unit______________________ Torok formation and Nanushuk group un-differentiated____ _ ___-_-__-_-___________ Stratigraphic relations...____________________ Cretaceous system ______________________________ Lower Cretaceous series_____________________ Fortress Mountain formation.____________ Torok formation..._____________________ Lower and Upper Cretaceous series Nanushuk group ___________________________________ Kukpowruk formation..___-_________ Corwin formation______________________ Upper Cretaceous series Colville group______ Prince Creek formation__________________ Quaternary system..____________________________ Pleistocene and Recent._____________________ Arctic foothills province _________________ High-level terrace deposits_____-_-___ Low-level deposits-_____-_-_____-___ Arctic coastal plain province. ____________ Gubik formation.- .-_____-_____-__-Recent deposits..___________________ Coastal area west of Cape Beaufort.______ Petrography _______________________________________ Thin sections-__________________________________ PLATE 7. Index map of northwestern Alaska showing location of Utukok-Corwin region, physiographic provinces, and areas mapped from 1947 to 1953. 8. Geologic map of the Utukok-Corwin region, Alaska. 9. Generalized geologic map of the Utukok-Corwin region, Alaska. 10. Representative sections of the Kukpowruk and Torok formations. PLATE 11. Correlated generalized sections of Nanushuk group along the Kukpowruk River. 12. Correlated generalized sections of Nanushuk group along the Kokolik River. 13. Correlated generalized sections of Nanushuk group along the Utukok River. 14. Correlated generalized sections of Nanushuk group along approximate lat. 68°55' N. in 48 EXPLORATION OF NAVAL PETROLEUM RESERVE NO. 4, ALASKA, 1944-53 tive and 2 negative elements which strike east-northeast. Structural salients in 2 parts of the region may represent northeast-striking structural highs. The western structural province is characterized by northwest-striking thrust faults which alternate with southwestward-dipping sections or partial limbs of synclines. This structural pattern is the result of eastward-directed forces from the Tigara uplift, west of the area. Reflection seismic work has been done north of the Utukok River at the headwaters of the Kaolak River, and southward along the Utukok River into the southern foothills. Two areas that are structurally distinct are delineated within this region. They are separated by the major south-dipping and west-trending Carbon Creek thrust fault, which is believed to come to the surface within the Carbon Creek anticline. The northern or upper Kaolak River area includes the Torok, Kukpowruk, and Corwin formations. This shallow Cretaceous rock sequence is gently ...

on June 12, From this place the ?arty moved cevgp by back-packing, f~U & n g the r*aute indicated by camp locations, until they reached the eastern end of Lake Schrad.er on July 50 The vzious c a p sites were selected at or near caches that had previously been set out, so that it was not necessary to transport aryr food rqhi3,e marring cmp, canvas boat w i t h a s i d l o~t b w c. l motor, wk,ichs had becn cached previousu, was used for trsulsr>ol-tetiun on Zdce 2etsrs a d Lake Schrader, On J&J 7 George Cmyc a i d I;leyd Spetzimn jsined tb pWQat Lake Scbzader, & r , ifryc ~erscLneci with e~e party-m.i;U 2X~y 17, making nztsrid. contribations to the i:eolo[;ic s5udi.c~ i n t>.e 16cdnjiy of Lake Schra.des, G r , Spete~:~aiz, a b o t z s i s t working f o? t h e Arctic b 3 .