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Range, Alaska--report of 1998 field season: U.9. Geological Survey Open-File Report 80-888, 40 P a Porter, S. C., 1966, Stratigraphy and deformaum of Paleozoic section at Anaktuvuk Paas, central Brmks Range, Alaska: American Association of Petroleum Geologtsts Bulletin, v. 50, no. 5, p. 952-980. Tailleur, I. L., 1965, Low-volatile bituminous coal of Mississippian age on the Lisburne Peninsula, northwestern Alaska, in Geological Survey research 1965: U.S: Geological Survey Professional Paper 5254, p. 834-B38. Tailleur, I. L., Brosg6,W. P., and Reiser, H. N., 1987, Palinspostic analysis of Devonian rocks in northwestern Alaska, & Oswald, I). H., ed., Interna- tional Symposium on the Devonian System: Cal- gary, Alberta, Canada, Alberta Society of Petroleum Geologists, v. 2, p. 1345-1361. KIvivk Creek: A pad*lfble ZinN-er axwrence in the Kuna Formatian, westexn 8aird Mmtah, Alaska By Inyo Bled&, 13svld C. Wmhard, Steven M. cm&, Charles P. Mnyfield, and mill L. Tamem Zinc-lead-silver deposits h carbonaceous black shale and chert of the Mississippian and Pemsylva~lian Kuna Formation (MuU and others, 1982) sre currently attracting mining+ompany interest in the Red Dog district in the western De Long Mountains. The Red Dog deposit was recently reported to contain 85 million t of ore containing 17.1 weight percent Zn, 5.0 weight percent Pb, and 2.4 troy oz Aglt, and the nearby Lik deposit 25 million t of ore containing 12 weight percent combined Pb-Zn and 1.3 troy oz Ag/t (Jones, 1982). Reconnaissance geologic mapping in the northwestern Baird Mountains (area 2 of fig. 5) hes revealed an extension of the strata known to contain the Red Dog and Lik deposits, and stream-sediment geochemical sampling has identified an area with lead, zinc, and silver anomalies similar to those in the Red Dog district. The northwestern part of the Baird Mounttiins is made up of a stack of thrust sheets that have been warped into a northeast-striking anti form, the Agashashok anticlinorium (fig. 8). Facies contrasts occur between coeval rocks in different thrust sheets. Thrust sheets containing a similar lithostrati- graphic sequence are grouped into tectonostratigraphic units called allochthons; these dlochthons are exten- sions of the allochthons (previously called thrust sequences) in the De Long Mountains (Ellersieck end others, 1979). me structurally lowest allochthon in the Agashashok anticlinorium is the Brooks Range allochthon, which is ma9 up of at least five thrust sheets larger than 50 krn and numerous smaller ones. Each of these thrust sheets contains part or all of a single lithostrotigraphic sequence that is distinct from coeval sequences in the structurally higher allochthons. This stratigraphic sequence, called the Key Creek sequence after Key Creek in the De Long Moun- tains (Mull and others, 19821, is easily recognizable bccnuse it is the only sequence in the anticlinorium EXPLANATION 0 Ouaternary 5 Copter Peak allochlhon 4 Nuka Ridge allochthon 3 lpnavik River allochthon 2 Kelly River allochthon 1 Brooks RanQe allochlhon Contact- Approximately located I r Thrust fault-Sawteeth on upper plate A -T- Axis of the Agashashok anticlinorium Dralnage which contalns multlple samples wlth anomalous concentration of silver (Ag), copper (Cu), lead (WI, or zinc (Zn). Mlnimum anomalous levels in parts per mllllon (ppm) are: ~g: I ppm Cu: 60ppm Pb: 60pPm Zn: 400p~m Pigure 8.--Sketch map of northwest corner of Baird Mountains quadrangle, showing tectoncstrat igaphic units and location of anomalous streamsediment samples.
I that contains the Upper Devonian Rant Pork Shale and Kanayut Comlomerate, end the l'dis-ppim and Pennsylvanian Kuna Formatlan. Recognition of the Brooks Ranga allochthon in the Baird Mountains is important because all the known significant mineral occurrences in the De Long Mountains are in this allochthon (Mayfield and others, 1979). The Klvivik Creek drainage is in the northwest comer of the Balrd Mountains quadrangle and lles within the Noatak National Wilderness and Preserve. Attention was fnitldly drawn to this area because It contains several red3tained creeks slmilar to those in the Bed Dcg area. lnvestigatiohs in 1078 revealed a few high geochemical values, and gamma-ray intensi- ties as high as 24 times the average value (Curtis and others, 1979). Pollowup strearnsedlment geochemical sampling in 1979 and 1981 showed that several draln- ages in one area have anomaIously high elemental con- centrations (stippling, fig. 8). Copper, lead, and zinc were measured by both atomic absorption and semi- quantitative ernissjonspectrographic methods, end silver by emission gectrography only. Copper values range as high as 320 parts per mllllon @prn), lead values as high L% 360 pprn, zinc values as high as 1,200 ppm, and silver values as high as 20 ppm. 'be absolute abundance3 of, and the ratios between, copper, lead, and zinc are nearly identical to those in samples from streams draining the Lik and Red Dog deposits (Net- aieck and others, 1980). Nearly all the samples with the higher values are from streams that drain the Kuna Formation. No sulfides were found in pLace during reconnaissance mapping, other than some flnely dis- I seminated pyrite. On the basis of its geologic and I I geochemical similarities to rocks h the Red Dog district, the Brooks Range allochthon in the Agashashok anticlinorlum should be considered highly prospective for zlnc-Iead-sllver deposits of the Red Dog type. REFERENCES CITED Curtis, S. M., ROssiter, Richard, Ellersieck, I. P., May- field, C. P., and Tailleur, I. L, 1979, Gamma-ray values h the Misheguk Mountain region and h parts of Barrow, Teshekpuk, and Harrison 8ay quadrangles, Alaska, Johnson, K. Ra, and Williams, J. R., eds., The United States Oeologi- cal Survey in Alaska! Accomplishments during 1978: U.S. Geological Survey Circular 804-8, p. B14. Ellersieck, Inyo, Mayfield, C. P., Tailleu, I. L., and Curtls, S. M., 1979, Thrust sequences in the M isheguk Mountain quadrangle, Brooks Range, Alaska, 5 Johnson, K. M., and WUams, J. R, eds., The United State GeoIogicd Survey in Alaska! Accornpllshments during 1978: U.S. Geological Survey Circular 804-B, p. B&B9. Ellersieck, Inyo, Curtis, S. Ma, Gruzensky, A. L., May- field, C. F., and MUeur, I. L., 1980, Copper, lead, and zinc in stream-sediment samples from the De Long Mountains quadragle, Alaska: U.S. Geological Survey Open-File Report 80-795, scale 1:63,360, 3 sheets. Jones, A h , 1982, Red Dog ore deposit said spectaau- lar: Northern Miner, v. 67, no. 51, p. 1. Mayfield, C. F., Curtis, S. M., Ellersieck, hyo., and Tallleur, I. L., 1979, Reconnaissance geology of the Ginny Creek Zn-Pb-Ag and Nirniuktuk barite deposits, northwestern Brooks Range, Alaska: U.S. GeologlcJ h e y Open-Pile Report 79- 1092, 20 p. Mull, C. G., Taillwr, I. L., Mayfield, C. F., EUewieck, Inyo, and Cur&, S. M., 1982, New late Paleozoic and early Mesozoic stratigraphic unlts, central and western Brooks Range, Alaska: American Association of Petroleum Geologists Wetin, v. 66, no. 3, p. 348-362. By J. 'lbomss I)utro, Jr, All3son R PaLme, John K Jr., and William P. Roe& The recalcitrant rocks of Doonerak (cover photograph~ area I, fig. 5) yield thek secrets grudghgly. For many years, we have probed and sampled this anctent antlclinorium, part of the autochthonous basement of the central Brwks Range, Alaska (Dutro and others, 19761, in whlch folded and faulted volcdc rocks, metarnorphased fine-grained clastic rocks, and marble are intruded by dikes and sUls of two ages (470 m.y. and 350 rn.y.1. Upper Devonian (Prasnfan) strata Ue unconformably on parts of the mtlclinortum, and Lower CarbonLferous beds truncate all older structures with angular unconformlty (Orosgd and Reiser, 1971). During the Late Jurasslc and Cretaceous building of the ancient Brooks Range, all these rocks were intruded, folded, faulted, thrust northward, and uplifted to initlate Barly Cretaceous coarse clastic sedl m entation on the Arctic slope. What Is the age of the old metamorphic terrane of Doonerak? Because it is intruded by dikes as old as 470 m.y., we opined ln 1976 that .the sedimentary rocks might be Cambrian or Ordovician. This was not anuninformed guess because similar an ticlinoria in the northeastern autochthonous Brooks Range contain Pussiltferous Lower and Upper Cambrlan and Middle Ordovlaian rocks In analogous terranes that also include volcanlc rocks (Reiser and others, 1971, 1980). Of course, It may be pospible that only Precambrian strata are present near Doonerak. In previous summers, we spent many hours lo&ing for graptoUtes in the fine-grained mks, but to no avail. Several samples were processed for possible microfa~sils, again with no results. At last, during the 1981 summer field seesan, we found megafossils in sandy Limestone that ia intimately associated with the black fine-gralned elastic sequence. h the hills south of Wolf Creek, nem the north margin of the anticlinorlum (fig. 9), several fsohted gray marble bodies are surrounded by black siltstone and 8rgilllte and intruded by greenstone dikes. Just above one of these marble bodies, in brownweathering sandy limestone, we found many trilobite fragments and a iew brachiopads. According to A. R. Palmer, these trilobites include Kootenia cf. 5 anabarensls Lermontova, "Parehmania" &L& Chernysheva, and Pagetla sp. and are most Ukely earw Middle Cambrian, corrdative with the Arngan Stage of Siberia. The brachlopods are Niswla sp., a common Middle Cambrian genus. A samplefrom the same beds was prcreeSed for microfossils by J. & Repetski, Jr.,
Page 1 and 2: n Alas Accompli: ' I.S. GE OLOGI CA
Page 3 and 4: I CONTENTS Page A bst raet ........
Page 5 and 6: -- --A I ALASEU i nued rral expluru
Page 7 and 8: ........ igure .JB. ;5~ercn map ox
Page 9 and 10: . , ".,k a. ,.e ,\a 1 y U11 IIIUUII
Page 11: THE UNITED STATES GEOLOGICAL SURVEY
Page 15 and 16: ~ t I r n t S i m ~ ~ Alarr a ~ man
Page 17 and 18: I -1977, RelImlnary documentat!on l
Page 19 and 20: I I MaCenn, W. R., Perez, 0. J., an
Page 21 and 22: were deslgned to impMve the accurac
Page 23 and 24: Noatak Sandstom and is overlaln con
Page 25: I (Nilsen and others, 1981a); (2) f
Page 29 and 30: who found Westeqaardodina sp., posb
Page 31 and 32: Table 2 lists the means rtnd for th
Page 33 and 34: ' Noatak Vdley (fig. 129. This ice
Page 35 and 36: 3 EUMN OF MAP UNITS WAmWARY OUAERNA
Page 37 and 38: -om displacement of the cc tween th
Page 39 and 40: I US I Surlicial dcnrrua,ts [~dater
Page 41 and 42: I Plafker, George, Hudson, Travis,
Page 43 and 44: !omlensed iring vapors generated by
Page 45 and 46: and the thinning. -upward cycles .,
Page 47 and 48: Kellum, L. B., Devless, S. N., and
Page 49 and 50: 1912 sample (a mediumwey pumice blo
Page 51 and 52: various Utholagic units present Thu
Page 53 and 54: fault, and Its depositional basemen
Page 55 and 56: suggested by coplanar foUaticm and
Page 57 and 58: 1 slgnlficarrtly more umnlum (73&1,
Page 59 and 60: ecrSigtallized catadastic matrix of
Page 61 and 62: analyzed to determine whether Immob
Page 63 and 64: are tgplcd of both ocean-floor basa
Page 65 and 66: & Fclsic in~rutirt rucks 0 Eio~ite
Page 67 and 68: are Lrdlcated by coexisting @&ite+q
Page 69 and 70: (Mg3.09 pe2+ 0.69 pe 0.~1~0.01~~0.9
Page 71 and 72: westward into a narrow band that ex
Page 73 and 74: EXF'lANATIOW 66600' Contan-Apprnimn
Page 75 and 76: ! few fold closures are preserved.
Page 77 and 78:
even thickness and conform to irreg
Page 79 and 80:
(Alnus ap.), heaths (Ericaceae, + E
Page 81 and 82:
terrane extends at least 300 krn to
Page 83 and 84:
Table 19.--6tneral petrography of M
Page 85 and 86:
were measured on 8 12-in. mass spec
Page 87 and 88:
Thin lenses of cabonate packtone to
Page 89 and 90:
The cantwell(?) Pormation south of
Page 91 and 92:
in the 18 lava flows b thermoremane
Page 93 and 94:
Upper Cretaceous shale in contact w
Page 95 and 96:
Gran tz, Arthur, 1960, Generalized
Page 97 and 98:
at 15 to 20 percent. Primary Inolus
Page 99 and 100:
addition, this factor generally def
Page 101 and 102:
Joreskog, K. G., Klovan, J. E., and
Page 103 and 104:
Mineral qItWation end r ~ k t k W e
Page 105 and 106:
1 "~_liO-/ 200 1000 B roo C E % A B
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Smaller placer mines ere active on
Page 109 and 110:
Figme 62.-Plant fassils from the co
Page 111 and 112:
Hallam, Anthony, 1975, Alfred Wegen
Page 113 and 114:
u ALASKA Figure 65.--Sketch map of
Page 115 and 116:
F ' i a?.-Intertidal bluffs compose
Page 117 and 118:
C-s - - Figure 70.-Products of eros
Page 119 and 120:
curve is based indicates that 6.1 c
Page 121 and 122:
sampled is related to widespread ma
Page 123 and 124:
marble is alsa locally present In t
Page 125 and 126:
Bedding in the conglomerate ranges
Page 127 and 128:
1 purpose of this study wes to dete
Page 129 and 130:
The secona k~~-~ri?tation mmes that
Page 131 and 132:
epizonb'l granitic Miss, mixed with
Page 133 and 134:
40 40 Forbes, R. B., and Engels, J.
Page 135 and 136:
foliated and inequigranular end con
Page 137 and 138:
I I thy euheclra. Sphene anhedra an
Page 139 and 140:
Quartz Alkali feldspar Plagioclase
Page 141 and 142:
F'@m 85.--Sketch map of Juneau area
Page 143 and 144:
HoUister, L. 8, 1966, Garnet zoning
Page 145 and 146:
! ~ bI8oO, (IN PERMIL) ~lqp~e 87.-8
Page 147 and 148:
Figure 90.-Offshore ereas discussed
Page 149 and 150:
Preliminerg analpsis of miemfauna f
Page 151 and 152:
Survey tn Alaekai AccompUshments hh
Page 153 and 154:
Gecllogical Survey Open-File Report
Page 155 and 156:
I provenance, and tectonia sIgnific
Page 157 and 158:
Keith, T. E. C, Barnes, Ivan, afrd
Page 159 and 160:
Open-Flle Report 8P811C, 19 p. + 2
Page 161 and 162:
United States Qeological Survey in
Page 163 and 164:
, ,. nldslra poblisbe!d by Prior, D
Page 165 and 166:
60, Alaska: Offshore Technology Con
Page 167:
Author Index [Page number underscor
Page 170 and 171:
Parks. Bruce ......................
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