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This institution reserves the right to refuse to accept a copying order if, in its judgment, fulfillment of the order would involve violation of copyright law. 1 8 5 5 214 Article 122 COMPARISON OF LATE PALEOZOIC DEPOSITIONAL HISTORY OF NORTHERN NEyADA AND CENTRAL IDAHO By RALPH J. ROBERTS and M. RAY THOMASSON: Menlo Park, Calif., and Midland, Tex. Abstract.-Three major sequences of upper Paleozoic rocks CANADA have been mapped in northern Nevada: one deposited east of -·--1--7- the Antler orogenic belt, one within the belt, and one west of ZI I the belt. Recognition of comparable sequences in central 01 \ Idaho suggests similarity in depositional history of the two •.1 \ areas. el. \ 3 In 1960, sections of Paleozoic rocks in the area between Arco, Chal]is, and Hailey, Idaho (fig. 122.1), -»-f1 were visited by Roberts in company with C. P. Ross 1 \:, 2-to.' and other geologists of the U.S. Geological Survey. 1 00 / 41 Thomasson had previously studied sections of upper {) \ HAILEY 30'•- • Paleozoic rocks in central Idaho in 1956, 1957, and 1958 OREGON / OB"se•h ••ANG" •,• during fieldwork on his dissertation for the University 04/HaileF"1· ry// 0 101« of Wisconsin. 2• I DIA HO •01* The authors independently noted similarities between 4, : le upper Paleozoic rocks and tectonics of north-central ---I.-----00 Nevada, and those of central Idaho, which suggest that 1 04 4 4 / EXPLANATION the two areas have related depositional histories. 0 ef:, -***-..........7- Although rock units cannot be traced from one area to 1» 4* S East boundary the other because of the intervening volcanic rocks of 4 AvCarlinO,/ of orogenie belt the Snake River Plain, the stratigraphic succession, i f #/ Dashed where approxi- lithology, and structural histories are comparable. wherematelvconcealed;located; dottedque- Comparison of the sequences in the two areas is shown 1L 4f/'» ried where doubt036ful \/N E V /A D A C in the accompanying table and on figure 122.2. \ 521:Il \\ ROCK SEQUENCES \ In north-central Nevada, three contemporaneous \\ major sequences 2 have been described (Roberts and \\. · Las Vegas others, 1958) (fig. 122.26): (1) the Eureka-Carlin· \\ 0 F sequence, a combination of the Eureka sequence, 1 Shell Oil Co. 0 100 200 MILES \• 2 The term"sequence"is usedherein an informal senseto denoteageographically 1 discrete succession of major rock units that were deposited under related environ- mental conditions (Silber]ing and Roberts, 1962). A single name is applied to 8 FIGURE 122.1.-Index map of report area in Nevada sequence in order to avoid repeating all the formation names. In the same way, and Idaho, showing part of the Antler orogenic belt comparablesequencesinIdahoaregiveflinformalnamesoftheir own. and the Snake River Plain (stippled ·pattern). ART. 122 IN U.S. GEOL. SURVEY PROF. PAPER 475-D, PAGES Dl-D6. 1964. D1 D2 STRATIGRAPHY AND STRUCTURAL GEOLOGY Descriptions of late Pateozoic rocks in northern Nevada and central Idaho Sequence as shown in flg. 122.2 • Name, age, and thickness of formation Lithology Facies Northern Nevada Havallah Formation, Pennsyl- Upper part: Upper part: vanian and Permian, 10,000+ Calcareous sandstone, lime- Offshore 1)ut shoaling toward Havallah sequence ft stone, shale, minor con- the top. ( Roberts and others, glomerate 1958; Silberling and Lower part: Lower part: Roberts, 1962) Sandstone, shale, chert Offshore. Pumpernickel Formation, Penn- Argillite, chert, sandstone, Eugeosynclinal, mostly offshore sylvanian(?), 7,000+ ft greenstone and moderately deep water. Edna Mountain Formation, Sandstone, sliale, slialy lime- Nearshore, shallow water. Permian, 700+ ft stone Antler sequence Antler Peak Limestone, Upper Limestone, shaly and sandy Nearshore, shallow water. ( Roberts and others, Pennsylvanian and Permian, limestone 1958) 625 ft Battle Formation, Middle Penn- Conglomerate, sandstone, shale, Terrestrial to shallow-water ilia- sylvanian, 730+ ft limestone rine. Buckskin Mountain Formation, Sandstone, limestone Nearshore, shallow water. Permian, 1,200+ ft Strathearn Formation, Upper Limestone, fine conglomerate Shallow water. Pennsylvanian and Permian, 1,500+ ft Carlin sequence (AfterDott, 1955; Fails, Moleen and Toniera Formations, Liinestone, fine conglomerate, Shallow water. 1960) Lower and Middle Pennsyl- sandstone vanian, 3,200+ ft Tonka Formation, Lower Mis- Conglomerate, sandstone, shale, Offshore, foredeep, moderately sissippian to Pennsylvanian, graywacke deep water. 2,500+ ft Central Idaho Ketchum sequence Wood River Formation, Penn- Sandstone, calcareous sandstone, Mostly offshore, moderately deep (Unipleby and others, sylvanian and Permian, 8,000+ liIiiestone, cliert to shallow water. 1930; Bostwick, 1955; ft Basal conglomerate, 40-260 ft Thoniasson 1) Milligen Formation, Mississip- Argillite, siliceous argillite, cheri, Eugeosynclinal, 01Tshore, mod- pian(?), 7,000+ ft limestone, quartzite erately deep water. Congbmerate on Summit Creek, Conglomerate, sandstone, shala Sliallow water. Summit Creek sequence Upper Pennsylvanian, 1,910 ( Modified after ft Thomasson 1) Unnamed unit Shale Shallow water. Conglomerate in Muldoon area, Conglomerate, shale, sandstone, Shallow water. Lower Pennsylvaniati, 1,324 ft liniestone Muldoon Formation: Foredeep, offshore: Wildhorse Member, Upper Shale, minor conglomerate, lime- Aioderately deep water. Mississippian or Lower stone Star Hope sequence Pennsylvanian, 2,586 ft ( Modified after Thomas- Iron Mine Member, Upper Conglomerate, sandstone, silt- Do. sol) ; 1 Ross, 1960; Skipp, Mississippian, 3,650 ft stone, mudstone 1961 M Garfield Member, Upper Sandstone, siltstone, mildstone Do. Mississippian, 2,587 ft Copper Creek Member, Lower Graded graywacke, black sliale Do. Mississippian, 861 ft Unnamed shale member, Siliceous argillite, 111inor chert, Moderately deep to deep Lower Mississippian, 4,000 ft sandstone, limestone water. 1 See footnote 3, p. D#. ROBERTS AND THOMASSON D3 ANTLER OROGENIC •BELT Havallah sequence r---.r--\-Antler sequence • Carlin sequence c-7..5-1.•05353•Rplilry,epulae:les.3' /aoess THFUST• Pre-Mississippian%- ».<--1*carbonate'' ••ZE•Z•1_Z__2'assemblage - . -4 A. Northern Nevada, Mississippian through Early Pe•rmian. 1 Following the Antler orogeny, sediments of the Antler sequence were deposited near the orogenic belt and those of the Havallah and Carlin sequence farther offshore 7-FRIZ:22...&- •.:Ifi34-14/GOLCONDA THRUST )0-44/•u•,, I ......11 -• - /1 ItlitC L L---/ kr-- -,31 /n \\L,i l.v4,,4J /./'A.-.U...3::•/(9377-129/ \\i/"Ir \S•1 1 w#4- 4-,23...://li-l-':'-:• : ','. Z, - ' ' ' ' ' ' ' ..1.L.1-_r_ 1 ) < ••••S•I•OUNTAINS THRUST ..tri-•.,1..•DE.••••,6.50----,-,-'-----I--------r---<-1-,1, B. GolcondaNorthern Nevada,thrust, andLateclasticPermian.rocks wereDuringshedtheintoSo•omaeasternorogeny,Nevadathe Havallah sequence moved eastward on the Summit Creek Ketchum sequence , csequence, Star Hope sequence •,03602t»1,0•«,•i•••••1 1 1.· 1.- I. .1.· i./-- >'.r '1 .2//1,:T:.7.2::.• ...E036=E-- '.'«4•9'/7•/// , ».©g®3 - -- --=-1.., t .«'15:/f..=tc33-7<p•(*f/, 7,»,e'*' F Pre-Mississippia, / r &4.-r----r onaterocks C Central Idaho, Mississippian through Early Permian. Following the Mississippian orogeny, sediments of the quencesSummit Creekfarthersequenceoffshore were deposted near the orogeAic belt and those of the Ketchum and Star Hope se- 1««=»»»,»=1•<«111-iI•t.< L HA»«»•R«3•/7,•5•/*Flir••'••f•'6'=*-)-47:LJI•,L#-mi•** -1--1.«1- '1 '1 .1 f '1 .1' 1' 1' '' " '1•12\<2523=7 / 1 1-LS.-4,--•A-256«eR.i»i3»•»-;• ,•t .•5.'.'. '1'..1'' ' '' '.''.' :...'' \»--Ss/-»*/- D. Central Idaho, post-Early Permian. eastward on the Hailey thrust During the post-Ea•rly Permian orogeny, the Ketchum sequence moved EXPLANATION 1 ---*-LL. 5%8 1 '-- Conglomerate Shale and graywacke Limestone A-/-4 Sandstone Bedded chert Shaly limestone Shale or argillite Vol«•rlock Dolomite FIGU RE 1222.-Diagrammatic sections showing a comparisonin *ntralof lateIdaho.Paleozoic depositional history in northern Nevada with that D4 STRATIGRAPHY' AND STRUCTURAL GEOLOGY (composed of the Chainman Shale, Diamond Peak recognized only at one place, on the ridge at the head Formation, Ely Limestone, and the Carbon Ridge and of Summit Creek. They are here called the Sunimit Garclen Valley Formations, exposed in the Eureka area) Creek sequence (figs. 122.2 C and 122.3) . This sequence (fig. 122.1 ), and tile Carlin sequence exposed farther consists of about 1,900 feet of conglomerate, sandstone, north (composed of the Tonka, Moleen and Tomera, and shale of Pennsylvanian age (Thomasson 3). The Strathearn, and Buckskin Mountain Formations of basal unit,