GEOLOGYGEOLOGY OOFP THETHE WESTWEST TINTICTINTIC MININGMINING DISTRICTDISTRICT ANDAND VICINITYVICINITY

JUABJUAB COUNTY,COUNTY, UTAHUTAH

BByy

WestonWeston CliveClive GardnerGardner

A thesisthesis submittedsubmitted toto ththee facultyfaculty ofof thethe UniversityUniversity ofof utahUtah inin partiapartiall fulfillmentfulfillment ofof thethe requirementsrequirements forfor thethe degreedegree ofof

MASTERMASTER OFOP SCIENCESCIENCE

DepartmentDepartment ofof GeologyGeology UniversitUniversityy ofof UtahUtah June,June, 19541954

Approved:Approved:

355 Chairman, Supervisory Committee-7

Reader,Reader, Supervisorvisoryy CommitteeCommitt ACKNOWLEDGMENTSACKNOWLEDGMENTS

TheThe authorauthor isis deeplydeeply indebtedindebted toto Dr.Dr. NormaNormann C.C.

Williams,Williams, whowho suggestedsuggested thethe thesithesiss problemproblem andand guidedguided itit ttoo conclusion.conclusion. HisHis adviceadvice onon specialspecial problemproblemss en­en­ counteredcountered inin thethe fieldfield andand inIn preparatiopreparationn ofof thethe manu­manu­ scriptscript waswas anan importantimportant factorfactor inin ththee completioncompletion ofof thethe reportreport.•

TheThe writewriterr wouldwould alsoalso likelike ttoo expresexpresss hishis gratitudegratitude toto Dr.Dr. WW.. L.L. StokesStokes foforr hihiss identificationsidentifications ofof fossilfossil collectionscollections andand stratigraphicstratigraphic advice;advice; andand toto DrDr.. F.F. W.W.

ChristiansenChristiansen andand ProfessorProfessor MaMaxx EricksonErickson ofof thethe thesisthesis committee.committee.

ManyMany thankthankss araree alsoalso duduee HalHal MorriMorriss ofof thethe EurekaEureka branchbranch ofof ththee UU.. S.S. GeologicalGeological Survey,Survey, whwhoo contributedcontributed valuablvaluablee stratigraphicstratigraphic assistancassistancee onon a tritripp throughthrough thethe area,area, andand whowho wawass a constantconstant sourcesource ofof information.information.

FinancialFinancial aidaid wawass receivedreceived fromfrom a UnionUnion PacificPacific

RailroadRailroad assistanceshipassistanceship grant.grant.

335646 i TABLTABLEE OOFP CO}~ENTSCONTENTS

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INTRODUCTIOI NTRO DU CTI 0N N • • • • • • • • • • • • · . • • • 11 PurposPurposee anandd ScopScopee • • • • • ...... • • • • • •. • 11 GeneraGenerall StatementStatement • • • • • • • • • • 11 LocatioLoce. t ionn anandd AccessibilitAccess i bil i tyy ...... • •• • • • •. • 2 FielFieldd WorWork.k • • • •• • • • • ••• • • • • • 33 GeographGeographyy • • • • • • • • • • • • • • • • 33

ClimatClimatee anandd vegetatiovegetationn ••••• :33 TopographTopographyy anandd drainagdrainagee ••••• · . 4 PreviouPreviouss GeologiGeologicc WorWork.k • • • • • • • • • 55 EconomiEconomicc Geology .•••••••• ... · . . . . 55 STRATIGRAPHSTRATIGRAPHYY . . . . . • • • · . . . • • . . . 99 GeneraGenerall Statemenstatementt • ...... 9 PrecambriaPrecambriann System.System · ...... 9 OrdovicianOrdovician SystemSystem • • • • • • • • • • • • 1111

PogoniPogonipp formation.formation • • • • • • • •• 1111 EurekEurekaa quartzitquartzitee • • • • • • • • • • 11II FishFish HavenHaven dolomite .•••• ...... ~ • • •. • 1313 SilurianSilurian SystemSystem •. • • • • • • • • • • · . 1414 LaketownLaketown dolomitedolomite •• • • • • • • • • 1414 DevonianDevonian SystemSystem • • • • · . . . · . . . . 1414 SevySevy dolomite.dolomite. • • • • • • • • • • • 1515 SimonsonSimonson dolomite.dolomite • • • • • • • • • 1515 GuilmetteGuilmette formatformatio ion.n • • • • • • •• 1616

CarboniferousCarboniferous System.System • • • • • • • • • • 1919 GeneralGeneral statement..statement •• • • • • 1919 GreatGreat BlueBlue formationformation • • • • • • • • 2020 MississippianMississippian undifferentiatedundifferentiated •.. ••. 2323 OquirrhOquirrh formation.formation • • • • • • • • • 2323 CretaceousCretaceous SystemSystem · . . · . . . · . . • • 2525 Devil'sDevil !s GatGatee ConglomeratConglomerate.e · . . . . 2525

iiii Il111l

PagPage©

QuaternarQ.uaternoryy SysteSystemm • .. • .. • ...... • • • • .. .. • 2525 QuaternarQuaternaryy colluviucolluviumm •..... » * • • • • 2525 QuaternarQuaternaryy pedimenpedlffientt gravelsfravels...... " . .. 2626 Quaternar{~uQternQryy alluviualluvIum.m • ...... · . . .. 2626 IGNEOUIGNEOUSS ROOKHOCKS.S • · .. • • .. .. • .. . .. • • .. .. •• 2727 IntrusivIntrusivee rockrookss • • • .. .. •• .. .. · .. • 272? T!!xtrns i VEl rocks • • • • • • • ...... • 28 Extrusive rocks ...... 28 STRUCTURE. • • .. .. • ...... • • .. • ...... 30 STRUCTURE. . 30 Regionr:l Structure. .. " .. · .. . RegionaFolds • l .. Structure...... • . .. • • • • • ...... 30 Folds · 30 Brown'Brown'ss RidgRidgee horaocllnehomocllne...... 3030 MaplMaplee PeaPeal.::k onticlSntmticl!ne© • • to • • .• 3131 MclntyrMclntvree foldfoldss • ...... • ...... • 3232 FoldFolds·s Iinn southernsouthern ViestWest ^intlminttec area.area . 3333

FaultsFeults.. . .. • • • • • • ...... • •. •. •.. 3333 WesVlestt '!'intlcTlntic thrusthrustt ...... • • • • .. • •. .. 3333 VernonVernon Creel{Creek feulfault t •...... • • • • • • •. .. 3535 SouthernSouthern VV;eat est 'f'1ntioTlntio fault ..... 3636 fAult • " • • .. MinorMinor raulfault tss • • .. • • • • ...... • • . • 3636 GEOMORGE0M0RPH0L0G PHOLOGYY • • • .. · .. • • • · .. • • .. • • • 3737 GEOLOGICGEOLOGIC In:,TCHYHISTORY • .. • • • • • • • • • .. • • • 39 GeneralGeneral statementStatement • .. • • • • •..... · ...... 3939 Prec~mbrlsnPreCambrian EistoryHistory ...... • .. • ...... • 3939 PsleozoicPaleozoic HIstoryHistory •...... • .. .. · .. · .. . .. 4040 Mesozoic•;:es©zoie History.History. .. • .. • .. • .. • • ...... 4040 CenozoioGenozolo Historv..History ...... • • .. . • • .. 4141 BIBLIOGRABIBLIOGRAPH PRYY • • .. .. . • .. .. • • ...... • 4343 tIST OF ILLUSTRATIOnS

followinfollowingg pagpapoe PlatPlatee I IndeIndexx mamapp oof'f ththee Wes':~e8tt TintiTlnttcc d1.str1.ctdistrict anandd vicinityvioinity,. UtaUtahh ...... • • • • • • • • •. • a2

PlatPlate© IIII AA. * Ital,rallsiy sites tea,, spSpa. founfoundd neanearr ohertchert F.onzonee oonn Brown'f3rown'ss RidgRtd!!oe ....••••••. • 1111

Sv VieVieww lookinlooklnrg northnorth slonaalong strikestrike ofof OrdoviciaOrdovlo1nnn anendd SiluriaS11urlflnn dolomt.+:esdolomites whicWhichh forfermm Brown'Brown'ss RidgeHtdge .•••• ... *~

PlatPlatoe IIIIII CorrelatioCorrelationn ooff West.Vest *Tintto intic IMinln~ inlng districtdistrict sectioseotionn witwithh nearbnearbyy areoresa sections~eotions.. ••• • 1618

PlatePlate IIVf Aft.• . VieVieww lookinlooldn,Q'g nortnorthh aatt thethe l)vvtl'Devil' ss GatGatee conglomeratconglOttera tee restinrest inf"g unccn­uncon­ formabl.formablye upouponn shaleahaless anandd qUArtzttosquartzttes ooff Uppetipperr M.isslssippia iss is s 1ppienn ageaga., •« •. .., 2525

I.B. VieVieww showingshowing larglargoe 1l!1t!,t1l8r'angular fr9g­frag­ mentmentas ooff PaleozoiPaleozoicc ltmestoneslimestones inin ththee Devil*Devil' as Gat(;atee oonglomerntoconglomerate •. * •

PlatoPlato V PhotomicrograpPhotomicrog'I'aphh ofof rhyolitrhyolitee flofloww fromfro© WestWest Cherr(~her:ryy Cree\Jreekk ValleyValley., showingshowing fracturefI'80turedd pnenocrystphemocI'ystss ofof quartquartzs andand orthoelasorthoole se© ...... • • • • • • • • • • • .... 2929

PlatePlate VIVI PhotomicrographPhotomicrograph ofof flndosandosit itoo f1.ow.flow inin southarnsouthern Westwest TlntioTintic Valley,Valley, showingshowing lsrgelarge euhedraleuhedral phenocrystsphenocrysts ofof hornhlendedhornblendad inIn a fino-grainedfine-grained groundmllf.\Sgroundraass •...... • .... 2929

PlatePlate VIrVII A.A. ViewView lookin,vlooking southsouth aloop:along thethe axisaxis ofof thethe MapleMaple PeRMPeak ~mtle11neanticline •. •. • 3131 B.B, 'JiewView showingshowing quartzitequartzite bedsbeds ovor­over­ turnedturned InIn 4::hethe corecor© ofof thethe : ¥\~apleaole PeakPeak ontte1ineanticline. •••••••••• ......

PlatePlato \1'1VII I II 1\A .•. \fiewView showin-rshowing minorminor fJ,ntanticlina lel '1.n91l foldfold inIn quartzitesquartsitea inIn thethe Vapl"SIplee PeakPeak ant.anticlin 101 ince •...... • • • • • • • • • •. • :3131

P. ViewView lookinglooking northnorth atat f08S1.1'1-fossilI- ferousforous 1limestone imestoness ofof LowerLower PennsylvanianPennsylvanlan ageage expoexpose oedd beneathbeneath EoceneEocene extrus1vesextrusivea •...... • • • • • . • ® •

I.iv PlatPlatee IIXX VieVieww lookinglooking northnorth atat basbasee ofof WesWestt TinticTintic thrustJ:;~ustt inIn ScotiaScotia sree.area • •. • •. « • • • • • • 3535

PlatePlate X AA., VieVieww showingshowing quartzitequartz ite klippeklippe restingresting oonn GreatGreat BlueBlue limestonelimestone withwith VernonVernon CreekGreek faultfault atat ththee basebase ofof tbethe escarpmentescarpment • • • • • • • • • • • • • 3636

B.B. VievTView shoW"!showin ngg verticaverticall ridlleridge formingforming limestoneslimestones oo~f LowerLower Pennsylv8nianPennsylvanlan ageage offsetoffset byby minorminor faultinfaultingg • ... • • •.

PlatePlate XXII Stratif':raphicStratigraphic columncolumn ofof thethe WestWest TinticTintic districrHstrictt andand vicinivicinity t~,, JuabJuab County,County, Utah.Utah. Follow­Follow** inging p.p. 4343

PlatePlate XIIXII GeologicGeologic mamapp andand crosscross sectionssections ofof thethe WesWestt TtntiGTintic districtdistrict •••••••••••...... • InIn pocketpocket • * •

v INTRODUCTIONINTRODUCTION

PurposPurposee andand ScopeScope

GeologistsGeologists havehave beebeenn concernedconcerned forfor manymany yearyearss withwith thethe signiricancesignificance ofof thethe zonezone ofof upliftuplift,, intrusion,intrusion, andand minerali­minerali­ zatiozationn whichwhich extendsextends westwarwestwardd frol"lfrom thethe UintaUinta ArcArchh throughthrough thethe ParkPark City,City, Alta,Alta, andand BiBigg CottonwooCottonwoodd stocksstocks toto ththee Bing­Bing­ hamham stock,stock, andand thencethence viavia a sharpsharp turnturn toto ththee southsouth intointo thethe

TinticTintic andand WesWestt TinticTintic districts.districts. IItt isIs thethe intentIntent ofof thethe presenpresentt investigationinvestigation ttoo contributecontribute toto ththee knowledgeknowledge ofof thethe

WestWest TinticTintic portionportion ofof thisthis mineralizemineralizedd belt.belt.

ThisThis studystudy iiss oneone ofof severalseveral beinbeingg undertakenundertaken inin thethe

SheeprockSheeprock MountainsMountains andand adjoiningadjoining areasareas underunder thethe directiondirection ofof Dr.Dr. HN.. C.C Williams.Williams. VeryVery littlelittle previousprevious detaileddetailed geologicgeologic worworkk hahass beebeenn donedone inin thithiss area,area, andand thisthis studystudy constitutesconstitutes ththee firstfirst detaileddetailed mappingmapping programprogram.. InterpretationsInterpretations ofof geologicgeologic historyhistory areare offered,offered, butbut maymay bbee subjectsubject toto modifi­modifi­ cationcation asas moremore date.data accumulatesaccumulates fromfrom ththee studiesstudies beingbeing con­con­ ductedducted inin adjoiningadjoining areas.areas.

GeneralGeneral StatementStatement

TheThe WestWest Tlnt1cTintic andand SheeprockSheeprock MountainMountainss areare moremore oror lessless northnorth trendingtrending rang,ssranges whichwhich convergeconverge atat theirtheir southernsouthern ends.ends. TheTheyy ereare topographicalltopographicallyy separatedseparated bbyy a lowlow saddlesaddle

1 2 frofromm whicwhichh ththee heaheadd waterwaterss ooff southwarsouthwardd flowinflowingg CherrCherryy CreekCreek anandd northwarnorthwardd flowinflowingg VernoVernonn CreeCreekk originateoriginate.. ThesThesee rangesranges araree typicatypicall iinn generagenerall appearancappearancee ooff ththee nortnorthh trendingtrending rangerangess ooff ththee BasiBasinn anandd RangRangee provinceprovince.. ThThee normanormall faultingfaulting whicwhichh mamayy havhavee elevateelevatedd anandd tiltetiltedd thesthesee rangeranress isis,, exceptexcept foforr ththee VernoVernonn CreeCreekk faultfault,, obscureobscuredd bbyy a thicthickk covecoverr ofof alluviumalluvium,, anandd onlonlyy theitheirr relierelieff suggestssuggests theirtheir fault-blockfault-block naturenature..

LocationLocation anandd AccessibilityAccessibility

ThThee regioregionn describedescribedd iiss locatelocatedd iinn ththee southersouthernn Sheep­Sheep­ rocrockk anandd WesWestt TintiTinticc MountainMountainss ooff northeasternortheasternn JuaJuabb County,County,

DtahUtah (Plate(Plate I).I). A portionportion ofof TooeleTooele CountyCounty isis includedincluded inin ththee northwesnorthwestt portioportionn ofof thethe area.area. TheThe regionregion embracesembraces anan areaarea ofof approximatelyapproximately 6565 squaresquare miles,miles, andand includesIncludes allall oror portionportionss ofof T.9T.9 anandd lOS,10S, R.4R.4 B.ndand 5W,5W, S.LoB.S.L.B. andand MM.. TheThe areaarea cancan bebe reachereachedd bbyy variousvarious dirtdirt andand gravelgravel roadroadss duringduring mostmost ofof thethe year;year; however,however, traveltravel becomesbecomes hazardoushazardous toto impossibleimpossible afterafter rainstorms,rainstorms, andand duringduring pe.rtpart ofof -thethe winterwinter thethe roadsroads areare completelycompletely drifteddrifted inIn byby snow.snow. A gravelgravel roadroad trendingtrending west­west­ wardward fromfrom EurekaEureka throughthrough thethe smallsmall railroadrailroad stationstation atat TinticTintic

isis thethe mostmost convenientconvenient meansmeans ofof access,access, butbut a roadroad extendingextending northwardnorthward fromfrom JericoJerico onon U.U. S.S. HighwayHighway 6,6, althoughalthough a somewhatsomewhat longerlonger route,route, isIs usuallyusually keptkept freefree ofof snowsnow duringduring thethe winterwinter ! 'u' c '

, \ I ( I ... ( ------, I L _"1- 1- l s cole m mi les \ 10 0 10 I ~ I J

INDEXINDEX MAP-SHOWINGMAP-SHOWING LOCATIONLOCATION OFOF WESTWEST TINTICTINTIC DISTRICT,DISTRICT, JUABJUAB COCO..,, UTAHUTAH 3 monthsmonths andand isis betterbetter maintainedmaintained thanthan ththee others.others. AccesAccesss maymay alsoalso bebe gainegainedd overover a dirtdirt roaroadd whichwhich followsfollows VernonVernon CreekGreek southwardsouthward throughthrough BenmoreBenmore fromfrom Vernon.Vernon.

WithiWithinn ththee areaarea describeddescribed inin thisthis report,report, traveltravel byby passengepassengerr carcar cancan bbee accomplishedaccomplished overover manmanyy dirtdirt roadsroads whichwhich interlaceinterlace thethe countryside.countryside. TravelTravel hyby jeepjeep,, oror horseback,horseback, andand byby footfoot isis necessarynecessary toto seesee manymany ofof ththee geologicgeologic features.features.

FielFteldd WorkWork

FieldField workwork wawass begunbegun inin AugustAugust,, 19531953 andand waswas completedcompleted duringduring ththee SpringSpring ofof 1954.1954. MappingMapping waswas donedone .onon UU.. S.S. Dept.Dept. ofof AgriculturAgriculturee aerialaerial photophotoss atat se scalescale ofof 1:20,000.1:20,000. SinceSince nono detailedetailedd planimetriplanimetricc basebase mapsmaps existed,existed, thethe radiaradiall lineline methomethodd asas describeddescribed bbyy AA., J.J, EardleyEardley (1941,(1941, pppp.. 55-69)55-69) waswas useusedd ttoo preparpreparee ththee basbasee mapmap.. BasBasee ofof operationsoperations waswas a cabincabin nearnear thethe WarWar EagleEagle workingsworkings,, whicwhichh waswas useusedd withwith thethe permissionpermission ofof thethe presentpresent leasorsleasors ofof thethe property.property.

GeographyGeography

ClimateClimate andand VegetationVegetation

TheThe areaarea isis oneone ofof sparsesparse rainfalrainfalll andand accordinglyaccordingly veryvery littlelittle vegetativevegetative covercover,, withwith sagebrush, andand cedarcedar treestrees

(junipers)(junipers) predominating.predominating. A fewfew sprucespruce andand pines,pines, althoughalthough quitequite rarerare,, areare foundfound atat highehigherr elevationselevations inIn somesome localities.localities. 4

Me.nyMany smallsmall springssprings andand grassesgrasses inin ththee 'ralleysvalleys supportsupport grazinggrazing inIn thethe summersummer months.months. AlfalfaAlfalfa andand ryryee areare reisedraised inin WestWest

CherryCherry CreekCreek Valley_Valley.

TopographyTopography andand DrainageDrainage

TheThe WestWest TinticTintic andand SheeprockSheeprock MountainsMountains areare maturelymaturely dissecteddissected faultfault blocblockk mountainsmountains witwithh thethe highehigh~rr moremore ruggedrugged topographytopography inin thethe southernsouthern WestWest TinticTintic RangeRange andand inin thethe north­north­ ernern SheeprockSheeprock Range.Range.

DrainageDrainage ofof ththee areaarea isis accomplishedaccomplished hyby CherryCherry Creek,Creek, whichwhich drainsdrains southwardsouthward toto t.hethe SevierSevier DesertDesert.;; VernoVernonn Creek,Creek, whichwhich drainsdrains northwardnorthward intointo RushRush ValleyValley,, anCl.and bbyy numerousnumerous streamsstreams flowingflowing westwardwestward intointo TinticTintic ValleyValley andand thenthen south­south­ wardward toto thethe SevierSevier DesertDesert.. DendrlticDendritic drainaredrainage formedformed overover thethe thickthick homogeneouhomogeneouss sequencesequence ofof limestoneslimestones Bndand inin thethe igneousIgneous rockrockss isis ththee typicaltypical drainagedrainage patternpattern.. ParallelParallel drainagedrainage isis wellwell shownshown inin thethe PrecambrianPrecambrian sequencesequence wherewhere longlong consequentconsequent streamsstreams areare joinejoinedd atat righrightt anglesangles byby subsequentsubsequent streamsstreams cucutt intointo softersofter argillitesargillites betweebetweenn resistanresistantt quartzites.quartzites.

CherryCherry CreekCreek isis thethe pr!ncipalprincipal perenniaperenniall streamstream drainingdraining thethe region,region, andand isis fedfed byby a springspring three-quarterthree-quarterss ofof Ba milemile aboveabove thethe reservoir.reservoir. ManManyy otherother smallsmall springssprings intermittentlyintermittently contributecontribute toto ththee waterwater supply.supply. 5

PreviouPreviouss GeologiGeologicc WorkWork

ThThee onlonlyy publishepublishedd researcresearchh consistconsistss ooff a generagenerall studystudy

bbyy GG.. PF.. LoughliLoughlinn ooff ththee UU.• SS.. GeologiGeologicc SurveySurvey iinn 19201920,, andand

a studstudyy ooff ththee WestWest TintiTinticc districdistrictt bbyy BronsoBronsonn PF.. StringhamStrIngham

iinn 1942.1942, ThThee worworkk bbyy LoughliLoughlinn wawass ononee ooff a serieseriess ooff recon­recon­

naissancnaissancee studiestudiess madmadee bbyy hihimm ooff ththee mininminingg districtdistrictss betweenbetween

ththee TintiTinticc anandd ThomaThomass RangesRanges.. StrIngham'Stringham'ss worworkk wawass essentiallyessentially

a mineralogicalmineralogical studystudy ofof thethe WesWestt TinticTintic MiningMining District,District, withwith

a briebrieff resume'resume' ofof thethe geologicgeologic structurestructure andand stratigraphy.stratigraphy.

Stringham'sStringham's papepaperr includeincludedd a geologigeologicc anandd topographitopographicc mamapp ofof

ththee district.district.

EconomicEconomic GeologyGeology

ThThee areaarea considereconsideredd inin thithiss reporreportt andand surroundingsurrounding

localitieslocalities havehave longlong beebeenn ofof greagreatt interestinterest toto thethe £eologistgeologist

andand prospectorprospector inin thethe searchsearch forfor lead,lead, zinc,zinc, coppercopper,, silversilver

andand gold.gold. MostMost importantimportant byby farfar isis thethe TinticTintic district,district, 2525 milesmiles toto thethe east,east, whichwhich hashas beenbeen a leadingleading producerproducer ofof thesethese

metalmetalss inin UtahUtah sincesince 1865,1865, andand hahass a totaltotal productionproduction ofof

approximatelyapproximately ~4l5,000,000$415,000,000 (Hal(Hal Morris,Morris, personalpersonal communication).communication).

TheThe WestWest TinticTintic DistricDistrictt hashas alsoalso shownshown significantsignificant pro­pro­

ductionduction sincesince 1870.1870. ThisThis areaarea hashas beenbeen intenselyintensely prospectedprospected

asas evidencedevidenced byby thethe manymany smallsmall prospectprospect pitspits andand minemine shafts.shafts. 6

OOff thesthesee ththee ScotiaScotia,, IroIronn KingKing,, anandd TintiTinticc WesterWesternn (no(noww DesertDesert

TungstenTungsten)) werweree ththee leadinleadingg producersproducers.. ThThee ververyy unsatisfactoryunsatisfactory recorrecordd ooff productioproductionn iiss duduee ttoo ththee inclusioinclusionn ooff earlieearlierr pro­pro­ fitfitss witwithh ththee productioproductionn ooff ththee TintiTinticc districtdistrict.. LoughlinLoughlin

(1920(1920,, pp.. 439439)) estimateestimatess productioproductionn frofromm ththee ScotiScotiaa minminee sincesince

18801880 ttoo bbee abouaboutt 3,003,0000 tontonss ooff ororee valuevaluedd aatt approximatelyapproximately

$150,000.$150,000.

TheThe EricksonErickson,, ColumbiColumbiaa anandd BluBluee BellBellss Districts,Districts, whichwhich liliee farthefartherr nortnorthh iinn ththee SheeprockSheeprock MountainsMountains,, havhavee leadlead,, sil­sil­ veverr anandd zinzincc productioproductionn recordrecordss frofromm abouaboutt 18901890 toto 1910.1910. TheThe inabilityinability ttoo continucontinuee operationoperationss herehere,, asas iinn ththee WestWest TinticTintic district,district, beinbeingg duedue toto unsatisfactoryunsatisfactory meansmeans ofof transportingtransporting thethe oresores toto thethe mills.mills.

InIn moremore recenrecentt yearyearss ththee regioregionn hashas onceonce agaiagainn becomebecome oneone ofof economiceconomic interestinterest witwithh thethe discoverydiscovery inin ththee northernnorthern

SheeprockSheeprock MountainMountain ofof beryberyll disseminateddisseminated througthroughh a granitegranite intrusive.intrusive. BrushBrush BerylliumBeryllium Corp.Corp. initiatedinitiated anan extensiveextensive diamonddiamond drilldrill programprogram therethere duringduring 19531953 toto ascertainascertain thethe valuevalue ofof thisthis deposit.deposit.

TheThe discoverydiscovery ofof scheelitescheelite withwith ultra-violetultra-violet lightlight inin thethe WestWest TinticTintic DistrictDistrict inin 19401940 stimulatedstimulated explorationexploration ofof thethe oldold minemine shaftsshafts andand prospectprospect pits.pits. DuringDuring WorldWorld WarWar IIII thethe U.U. S.S. BureauBureau ofof MinesMines establishedestablished a developmentdevelopment projectproject '77 oonn somsomee propertpropertyy controllecontrolledd bbyy DeserDesertt TungsteTungstenn GoCo., ThisThis prograprogramm includeincludedd removaremovall ooff alluviualluviumm anandd trenchintrenchingg withwith bulldozerbulldozerss ttoo facilitatfacilitatee mappinmappingg bbyy membermemberss ooff ththee UU.. S.S.

GeologicaGeologicall SurveySurvey.. ThiThiss worworkk wawass followefollowedd bbyy a diamonddiamond drillindrillingg programprogram.. ThThee ororee wawass founfoundd ttoo bbee scheelitscheelitee dis-dis­ seminateseminatedd alonalongg ththee limestone-monzonitlimestone-monzonitee contaccontactt aatt aann averageaverage tenotenorr ooff .5%..5%, ThThee resultresultss ooff thithiss projecprojectt havhavee beebeenn publishedpublished iinn "Report"Report ooff InvestigationInvestigationss 4640."4640."

OrOree wawass firstfirst mineminedd anandd shippeshippedd iinn MayMay,, 19421942 ttoo a chemi­chemi­ calcal treatmentreatmentt planplantt westwest ofof SalSaltt LakLakee CityCity.. ThesThesee operationsoperations onlonlyy continuecontinuedd durinduringg WorlWorldd WaWarr IIII,, anandd DeserDesertt TungsteTungstenn Co.Co. isn'tisn!t mininminingg inin thethe areaarea atat thsthe presentpresent time;time; howeverhowever,, oneone smallsmall operationoperation isis stillstill beinbein~g carriedcarried on.on. TheThe oreore mineminedd isis a tactitetactite whichwhich isis sentsent toto Barstow,Barstow, CaliforniaCalifornia toto bebe milled,milled, andand laterlater sentsent toto Bishop,Bishop, CaliforniaCalifornia forfor furtherfurther refining.refining.

SomeSome ororee hahass beenbeen shippedshipped toto thethe plantplant westwest ooff SaltSalt LakeLake City,City, whichwhich separatesseparates thethe scheelitescheelite byby flotationflotation processes.processes. TheThe mainmain advantageadvantage ofof thisthis flotationflotation processprocess isis inin itsits highhigh raterate ofof recovery,recovery, whichwhich amountsamounts toto betterbetter thanthan 80%. ProfitsProfits fromfrom thisthis project,project, asas fromfrom earlierearlier operations,operations, areare reducedreduced byby thethe " greatgreat distancedistance thethe areore isis transported.transported.

ThisThis areaarea ofof study,study, then,then, isis oneone ofof variedvaried andand somewhatsomewhat complexcomplex mineralization.mineralization. TheThe depositsdeposits soso farfar havehave beenbeen ofof tootoo 8 llooww gradegrade toto offsetoffset thethe costscosts ofof transportation,, butbut withwith aa greatergreater demanddemand forfor thethe metalsmetals andand improvedimproved meansmeans ofof shippinshippingg andand treatingg thethe ores,, thisthis areaarea coucoull dd becomebecome ofof sisignificangnificantt eeconomiconomi c importanceImportance toto UtUtahah .. STRATIGRASTRATIGRAPH PHYY

GeneralGeneral StatementStatement

A thickthick seriesseries ofof PrecambrianPrecambrian metasedimentsmetasediments isis wellwell exposedexposed inIn thethe westerwesternn portionportion ofof thethe area.area. ExcellentExcellent expo-expo­ suressures ooff formatioformationn rangingranging iinn ageage fromfrom OrdovicianOrdovician throughthrough

DenoviaDenoviann cropcrop outout acrossacross thethe WestWest TintiTinticc MiningMining District.District.

FossilsFossils andand primaryprimary structuresstructures inin thisthis areaarea havhavee beebeenn ttoo aa greatgreat extentextent destroyeddestroyed bbyy hydothermalhydothermal solutionssolutions fromfrom t.hethe intrusiveintrusive toto thethe west.west.

InIn thethe scope'scope ofof ththee presenpresentt study,study, thethe ~iWrite t err waswas unableunable toto determinedetermine ththee sequencesequence ofof anyany greatgreat thicknessthickness ofof bedsbeds inIn ththee WestWest TinticTintic RangRangee duduee toto poopoorr exposuresexposures andand complicationscomplications / inin structure.structure. HoweverHowever,, somesome fossilsfossils indicatindicatee a CarboniferousCarboniferous ageage forfor most,most, ifif nonott all,all, ofof ththee sedimentssediments composingcomposing thethe

WesWestt TintiTinticc RangeRange inin thethe areaarea studied.studied.

PrecambriaPrecambriann SystemSystem

UndifferentiatedUndifferentiated quartzitesquartzites and, shalesshales

LoughlinLoughlin (1920,(1920, pp.pp. 432)432) firstfirst recognizedrecognized andand describeddescribed

"The"The thickthick formatioformationn ooff quartzites,quartzites, shalesshales andand shalyshaly conglom­conglom­ erateserates whicwhichh formsforms ththee bulkbulk ofof thethe SheeprockSheeprock RangeRange..." ••• ".. HeHe attributesattributes a PrecambrianPrecambrian ageage toto thisthis sequence,sequence, andand describesdescribes a formationformation whichwhich bearsbears a strongstrong resemblanceresemblance toto a glacialglacial tilltill

9 /I 10 whichwhich,, accordinacoordingg ttoo EardleEardleyy (1940(1940,, pp.. 823)..."i823) ••• "iss iinn alalll re-re­ spectsspects,, excepexceptt foforr compositiooompositionn ooff pebblepebbless anandd bouldersboulders,, thethe samsamee aass ththee tillitetillitess ooff ththee centracentrall anandd northernorthernn Wasatoh.Wasatch.11"

ThiThiss PrecambriaPreoambriann tillittillitee wawass nonott observeobservedd iinn ththee areareaa ofof thithiss reportreport;; howeverhowever,, ititss mentiomentionn herheree iiss Interestininterestingg andand importanimportantt ttoo ththee PrecambriaPrecambriann historhistoryy ooff ththee region.region.

ThThee basbasee ooff ththee PrecambriaPrecambriann stratstrataa iiss iinn thrusthrustt con-con­ tactactt witwithh underlyinunderlyingg PaleozoiPaleozoioc sedimentsedimentss witwithh varyinvaryingg degreesdegrees ooff discordancedisoordance.. ThThee quartzitesquartzites areare generallgenerallyy massivemassive,, 8ray,gray, , whitwhitee anandd brownbrown,, anandd weather^browweather~brownn ttoo purplish-brownpurplish-brown.. TheyThey araree finfinee ttoo mediumediumm grainedgrained witwithh a fefeww bedbedss ranginrangingg fromfrom coarsecoarse sandsand toto gritgrit sizedsized particles.particles. NeaNearr ththee thrusthrustt planeplane thethe quartzitequartzite hahass beebeenn thoroughlythoroughly brecciatebrecciatedd andand recemented.recemented.

TheThe shalesshales areare brown,brown, green,green, andand blaok,black, chloritichloriticc andand sericitio,sericitic, andand araree generallygenerally metamorphosedmetamorphosed toto slates,slates, phyllites,phyllites, andand hornfels.hornfels. ManyMany bedbedss containcontain cobblecobbless andand pebblespebbles ofof wellwell roundedrounded quartzite.quartzite. TheirTheir proximityproximity toto thethe thrustthrust faultfault isis indioatedindicated byby theirtheir extremelyextremely crumpledcrumpled nature.nature.

A PraoambrianPrecambrian ageage assumptionassumption isis justifiedjustified byby thethe faotfact thatthat CambrianCambrian stratastrata areare foundfound inin sedimentarysedimentary oontaotcontact con-con­ formablyformably overlyingoverlying thesethese metasedimentsmetasediments inin thethe northernnorthern Sheep­Sheep­ rookrock MountainsMountains (Walker(Walker Baker,Baker, personalpersonal communication).communication). 1111

OrdovicianOrdovician SystemSystem

PogonipPogonip formationformation

WestwarWestwardd fromfrom ththee OrientOrient minemine,approximately, approximately 10001000 feetfeet ofof bleachebleachedd andand metamorphosedmetamorphosed limestonelimestone andand dolomitesdolomites out­out­ cropcrop betweenbetween ththee monzonitemonzonite intrusiveIntrusive onon ththee southsouth andand thethe

PrecambrianPrecambrian quartzitesquartzites onon ththee northnorth.. BecauseBecause ofof theirtheir proximitproximityy ttoo ththee intrusion,intrusion, thesthesee sedimentssediments havehave beenbeen alteredaltered andand metamorphosedmetamorphosed untiluntil theitheirr primarprimaryy featuresfeatures havehave beenbeen toto a greatgreat extenextentt destroyed.destroyed. Therefore,Therefore, nono detaileddetailed measuredmeasured sectionsection couldcould bbee made.made. However,However, correlationscorrelations ofof overlyingoverlying formationsformations (Plate(Plate III)III) indicateIndicate thathatt thesethese lime­lime­ stonesstones anandd dolomitesdolomites,, includingincluding ththee shaleshale membememberr whicwhichh willwill laterlater bbee described,described, areare equivalenequivalentt toto thethe PogonipPogonip formationformation ooff LoweLowerr OrdovicianOrdovician ageage,with, with thethe lowerlower ~ortiont>or"tion possiblypossibly ex­ex­ tendingtending intointo UpperUpper CambrianCambrian timetime.. NNoo distinctivedistinctive sedimentarysedimentary changechange nonorr diagnosticdiagnostic fossilsfossils werweree foundfound toto determinedetermine thethe

Cambrian-OrdovicianCambrian-Ordovician contact.contact.

EurekaEureka qllartzitequartzite

StringhamStringham (1942,(1942, pp.. 271)271) describeddescribed a bedbed ofof quartzitequartzite andand a uniunitt ooff dense,dense, greenishgreenish browbrownn shaleshale whichwhich hhee referredreferred toto asas ththee OrientOrient quartzitequartzite andand OrientOrient shale,shale, respectively.respectively.

NearNear ththee outcropoutcrop ofof thesthesee unitsunits hhee foundfound fossilsfossils whichwhich werewere identifiedidentified 9.Sas OrdovicianOrdovician inin age.age. PoorlyPoorly preservedpreserved fossilsfossils PlatePlate IIII

),,' ... - I r I

,

A. HalysltesHalysltas 3psp. ~oundfound neanearr ccherh ertt zonezone oonn Brown'Brown' ss RidRidgege ..

--~- - ---

\

B., ViewView llookingooking, nnortorthh alonal ongg strikestrike ofof OrdovicianOrdovician andand SISilurial uriann dolodolomitemi tess whicwhichh forformm Brown'?ss RidgeRidge .. TheThe bedsbeds InIn thethe foregroundforeground araree dippidippinngg ttoo ththee east, , Rndand thethe bedsbeds 1inn thethe distandistanccee areare overturneoverturnedd ttoo dipdip toto thethe wwestest .. 1212 foundfound onon ththee easteast sideside ofof BrowntsBrown's RidgeRidge atat a8 horizohorizonn 12801280 stratigraphicstratigraphic feetfeet aboveabove thethe quartzitequartzite havehave beebeenn identifiedidentified asas UpperUpper Ordov!cian,Ordovician, oror possiblpossiblyy Silurian.Silurian. ThThoe occurrenceoccurrence ofof thesethese fossils,fossils, thethe favorablefavorable correlationscorrelations witwithh nearbnearbyy areasareas

(Plate(Plate III),III), andand lithologicllthologic similaritysimilarity ~oto ththee EurekNlrekaa qu~rt­quart­ zitszite ofof MiddleMiddle OrdovicianOrdovician ageage favorfavor suchsuch a correlationcorrAlatlon,, withwith thethe underlyinsunderlying OrientOrient shaleshale beIngbeing equivalentequivalent ttoo thethe upperupper sl1aleshale membermember ofof thethe PogonipPogonip formationformation ofof thethe HouseBouse Range.Range.

TheThe quartzitequartzite isIs whitewhite toto fray,gray, finefine ttoo mediurr.ediumm ~rained,grained, andand limonitellmonlte stainedstained onon weatheredweathered surface.surface. IItt containscontains a fewfew thinthin shaleshale partingspartings andand isIs notablnotahlyy clean.clean. AAtt oneone verticalvertical outcropoutcrop a veryvery accurateaccurate measure~ent.measurement ofof a 38-foooS-foott thicknessthickness waswas made.made.

TheThe metamorphosedmetamorphosed OrientOrient shaleshale isis dense,dense, blackblack ttoo oliveolive greegreenn Bndand brown,brown, whichwhich onon weatheredweathered surfacessurfaces isIs greenishgreenish brown.brown. TheThe upperupper contactcontac. t againstagainst thethe quartzitequartzite iiss sharp,sharp, butbut thethe lowerlower contactcontact iiss everywhereeverywhere covered,covered, andand itsits measuredmeasured thicknessthickness ofof 200 1t couldcould bebe subjectsubject toto considerableconsiderable error.error.

TheThe absenceabsence ofof fossilsfossils inin thethe quartzitequartzite andand shaleshale isIs ratheratherr unu~ual,unusual, stncesince thesethese formationsformations Inin otheotherr localitieslocalities areare veryvery fossiliferous.foss11 iferous• WalkerWalker BakerBaker (personal(personal co~munlcation)communication) reportsreports findingfinding manymany gra.ptolitesgraptolites inin thisthis shaleshale iinn ththee north-north­ ernern SheeprockSheeprock Mountains.Mountains. TheirTheir absenceabsence herehere mamayy possiblypossibly bebe duedue toto theirtheir destructiondestruction byby hydrothermalhydrothermal alteration.alteration. 1313

FishFish HavenHaven dolomitedolomite

ConformablyConformably overlyingoverlying thethe EurekaEureka quartzitequartzite isis 12801280 feetfeet ofof darkdark graygray dolomitedolomite herheree designateddesignated asas FishFish HaveHavenn dolomite.dolomite.

MuchMuch ofof thisthis formationformation isis bleachedbleached whitewhite,, andand containscontains tremo­tremo- litelite aggregatesaggregates attestingattesting toto contactcontact metamorphism.metamorphism. UnalteredUnaltered outcropsoutcrops areare darkdark graygray andand weatherweather lightlight blueblue graygray.. TheThe dolomitedolomite iiss brecciatebrecciatedd overover a greatgreat parpartt ofof itsits thickness,thickness, chertycherty neanearr itsits basebase,, andand withwith a chertycherty zonzonee andand chertchert bedbed atat itsIts upperupper contact.contact. InIn itsits upperupper portion,portion, bedsbeds ofof blackblack dolomitedolomite withwith thin,thin, graygray,, coarse-grainedcoarse-grained laminationlaminationss becomebecome prominentprominent.. WhereWhere foldingfolding hashas occurred,occurred, thesethese bedbedss resembleresemble thethe regionallyregionally useusedd lithologilithologicc term,term, "curly"curly bed."bed."

TheThe unusuallunusuallyy larglareee thicknesthicknesss ofof 12801280 feetfeet isis undoubt­undoubt­ edlyedly duedue toto inclusioninclusion ooff parpartt ofof thethe overlyingoverlying LaketowLaketownn dolo­dolo­ mitemite inin ththee unitunit.. HalHal MorrisMorris (personal(personal communication)communication) statesstates thathatt thethe uppeupperr contactcontact ofof thethe FishFish HaveRavenn isIs takentaken atat a markedmarked chertchert zonezone inin thethe TinticTintic districtdistrict,, butbut doesdoes notnot feelfeel tbatthat over­over­ lyinglying andand underlyinunderlyingg lithologylithology herheree sufficientlysufficiently resemblesresembles

TinticTintic districtdistrict sequencessequences ttoo justifjustifyy a contaccontactt atat ththee chertchert zone.zone. HoweverHowever,, becausebecause ofof ththee absenceabsence ooff ananyy distinctivedistinctive markermarker bedbedss belobeloww thithiss horizonhorizon,, thethe FisFishh Haven-LaketownHaven-Laketown con­con­ tacttact isis arbitrarilyarbitrarily takentaken atat ththee basbasee ofof thethe chertchert bed.bed.

HalysitesHalysites sp.sp. andand somesome poorlpoorlyy preservedpreserved semi-globosesemi-globose formsforms ofof brachiopodsbrachiopods ofof UpperUpper Ordovician,Ordovician, oror possiblpossiblyy Silurian,Silurian, ageage werewere foundfound nearnear thisthis chertchert zone.zone. 1414

SilurianSilurian SystemSystem

LaketowLaketownn dolomitedolomite

SilurianSilurian timtimee isis representedrepresented byby 945945 feetfeet ofof mediummedium graygray dolomite,dolomite, whichwhich weatherweatherss lightlight gray,gray, andand containscontains somesome chertycherty zoneszones andand a chertchert bebedd atat itsits basebase.. AsAs hahass beebeenn mentioned,mentioned, thisthis thicknesthicknesss mamayy nonott representrepresent ththee ententir iree formatformation lon,, asas partpart ofof ththee dolomitedolomite mappedmapped aass FishFish HaveHavenn isis parpartt ofof thethe Laketown.Laketown.

TheirTheir combinedcombined thicknessthickness ofof 22222200 feetfeet isis alsoalso large,large, asas comparedcompared toto 16051605 feetfeet iinn ththee ThomaThomass RangeRange toto thethe weswestt (Bauer(Bauer

1952),1952), andand inin ththee TinticTintic districdistrictt toto ththee easteast wherewhere thethe com-com­ binedbined FishFish HavenHaven dolomitedolomite anandd BluebelBluebelll dolomite,dolomite, whichwhich in-in­ eludescludes SilurianSilurian andand somesome Devonian,Devonian, totaltotal onlyonly aboutabout 13001300 feet.feet.

DrDr.. StokesStokes (personal(personal communicationcommunication)) suggestssuggests a locallocal thicken-thicken- s inging ofof thethe LaketownLaketown dolomitedolomite herheree asas a possiblpossiblee explanation.explanation.

DevonianDevonian SystemSystem

GeneralGeneral statementstatement

DevonianDevonian terminologyterminology inin thisthis reporreportt isis taketakenn fromfrom GoldGold

Hill,Hill, wherewhere excellentexcellent descriptionsdescriptions ofof lithologylithology byby NolanNolan (1935)(1935) suggestsuggest correlationcorrelation witwithh measuremeasuredd sequencesequence inin thithiss area.area. TheThe authorauthor realizesrealizes thathatt manmanyy formationalformational names,names, includinincludin~g Devon-Devon­ ianian terminology,terminology, areare useusedd onlyonly inIn GoldGold Hill,Hill, andand areare notnot generallygenerally accepteacceptedd inin mostmost surroundingsurrounding areas;areas; butbut,, onon thethe 1515 basibasiss ofof thethe favorablefavorable correlationcorrelation ofof mappablemappable unitunitss possiblepossible withwith thatthat area,area, suchsuch a correlationcorrelation waswas mademade here.here,

SevySevy dolomitedolomite

OverlyingOverlying thethe LaketownLaketown dolomite,dolomite, with, nnoo apparenapparentt dis­dis­ cordance,cordance, isis 700700 feetfeet ofof dolomitAdolomite andand dolomiticdolomitic limestones.limestones.

TheyThey areare lightlight gray,gray, weatherinweatheringg lightlight graygray ttoo creamycreamy white,white, andand areare fine-grained,fine-grained, platy,platy, breakbreak withwith conchoidalconchoidal fracture,fracture, withwith somesome thinthin bedsbeds anandd particlesparticles ofof pinpinkk chert.chert. TheThe upperupper contactcontact isis arbitrarilyarbitrarily takentaken wherewhere blubluee graygray weatherinweRtheringg dolo­dolo­ mitemite becomesbecomes thethe dominantdominant lithology.lithology.

SimonsonSimonson dolomitedolomite

ConformablyGonformably overlyingoverlying thethe SevySevy dolomitedolomite isis 434355 feetfeet ofof dolomitedolomite andand dolomiticdolomitic limestones,limestones, whichwhich areare darkdark gray,gray, weatheringweathering blueblue gragrayy toto darkdark gray,gray, andand bleachebleachedd whitwhitee iinn somesome portionsportions.. BlackBlack laminatedlaminated dolomitedolomite occursoccurs inin bedbedss aboutabout 22 feetfeet thick,thick, becomingbecoming moremore prominentprominent upward.upward. 'fIheThe dolomitedolomite becomesbecomes quitequite sandysandy inin thethe middlemiddle portionportion ooff thethe formation,formation, withwith sandsand decreasingdecreasing upwardupward andand chertchert increasingincreasing upward.upward.

CladoporaCladopora sp.sp. fossilsfossils areare foundfound atat thethe upperupper contactcontact,, wherewhere theythey constituteconstitute a distinctdistinct markermarker bed.bed. TheThe totopp ooff ththee forma­forma­ tiontion isis arbitrarilyarbitrarily takentaken wherewhere ththee dolomitedolomite becomebecomess massivemassive andand containscontains a highehigherr percentagepercentage ofof chert.chert. 1166

GuilmettGuilmettee formationformation

ConformablConformablyy overlyinoverlyingg ththee SimonsoSimonsonn dolomitdolomitee iiss 272700 feetfeet

ooff mediumediumm ttoo dardarkk gragrayy dolomitedolomite,, weatherinweatheringg grsgrayy ttoo blubluee gray,gray, witwithh somsomee bleachinbleachingg anandd witwithh somsomee chertchertyy beds.beds.

ThisThis isis,, iinn turnturn,, overlaioverlainn bbyy a 50-foo50-foott uniunitt ooff whitewhite

ttoo lighlightt gragrayy quartzitequartzite.. IItt iiss finfinee ttoo mediumediumm grainedgrained,, withwith beddinbeddingg prominentprominent,, andand witwithh crossbeddincrossbeddingg iinn somesome beds.beds.

StringhamStringham (1942(1942,, pp.. 271271)\ referrereferredd ttoo thithiss uniunitt aass ththee AllahAllah quartzitequartzite,, andand iinn thithiss papepaperr iitt wilwilll bbee referrereferredd ttoo aass thethe

AllaAllahh quartzitquartzitee membermember ooff ththee GuilmettGuilmettee formation.formation.

OverlyinOverlyingg ththee quartzitquartzitee iiss a 60-foo60-foott uniunitt ooff platy,platy, lightlight blue-grayblue-gray weatherinweatheringg limestone,limestone, withwith thin,thin, irregularirregular whitewhite calcitecalcite seamsseams parallelparallel toto thethe beddingbedding.. ThisThis limestonelimestone

becomebecomess cherty,andcherty, and gradegradess intoInto 250250 feetfeet ofof dolomitedolomite whichwhich isis

darkdark gray,gray, weatherinweatheringg lightlight gray,gray, andand locallylocally bleachedbleached.. TheThe lowerlower portioportionn containscontains somesome wellwell beddebeddedd limestonelimestone iinn bedbedss aboutabout

1 footfoot thick.thick.

TheThe aboveabove describeddescribed unitsunits willwill bebe tentativelytentatively designateddesignated asas thethe GuilmetteGuilmette formationformation ofof DevonianDevonian ageoage.

BedrockBedrock aboveabove thethe lastlast describeddescribed unitunit is,tois, to a greatgreat

extent,extent, obscuredobscured byby pedimentpediment gravelsgravels andand colluvill.'1l,colluvium, andand thethe upperupper contactcontact ofof thethe GuilmetteGuilmette formationformation hashas notnot beenbeen foundfound here.here. ExposuresExposures showshow thethe bedsbeds aboveabove toto bsbs limestoneslimestones andand r~>~

dolomitesdolomites withwith somesome locallocal bleaching.bleaching. OneOne bedbed ofof chertchert 2020

f PlatPlolee 11III1

CORRELATIOCORRELATIONN CHARTCHART PiloPil ott shashallee

i JJ i, r.nu GuilmettGuilmettee limelimestonst on e ui M3

n Guilmette fm. SevSe vyy dolomitedolomite XX /.V7 7. ZS/ 7 /,/, Z 7,/ . / SimoSirr,ann so<; onr, dolodolomitmitee GuiimettGUi lmette fm.. /, V, /,/, / 7 7, / ^3 SevSevyy dcldclomitomit e Simonson dolomite t. i'JL ------Slmonson dolomite , Mill \' 7 / "7 "7 FFisishh HHaveovenn doldol.. D ! ' I ' i ' r PPogoniogonipp grgrououpp 3n • gj ng£n CChokr,okeche cherrerryy dolodolomitmitee 'V , \ \W> OpoOpohonghongao Imst.Imst.

HouHouse-Confusiose-Confusionn WWesestt TinticTintic GolGo ldd HillHill EEasa ~tt tintic RRegioegionn RRangangee MiniMininngg DiDistricstrictt MiMininningg DDistricistrictt CompCompositioositionn SecSectiotionn (2)(2) 0)(3K , (1) (l) scale: I =-2000' 1 .. GuidebookGuidebook toto GeoloGeologgy ofof Utah,, NNoo .. 6 2 .. ThisThis paperpaper )3.'. UU.S.G.S. S. G. S.. Prof,. ^apeaperr 117777 4 r.1ensuredMeasured SectionSection inin Allen'sAllen's RanchRanch Quadrangluadrang lee ) (U(U.S.G.S. S. G. S. unpublishedunpublished literature)literature) 1717 feetfeet thickthick outcropoutcropss approximatelyapproximately 300500 yardsyards easteast ofof thethe PyramidPyramid workings.workings•

TheThe followingfollowing sectionsection waswas measuremeasuredd eastward,eastward, strattgraphi­stratigraphi callycally upward,upward, fromfrom thethe uppeupperr contactcontact ofof ththee EurekaEureka quartzite,quartzite, andand includesincludes allall formationsformations youngeryounger thathann thethe EurekaEureka quartzitequartz ite inin thethe WestWest TinticTintic MiningMining District.District. feetfeet 1.1• Limestone-bleacheLimestone-bleachedd white,white, granulargranular,, recrystallized,recrystallized, containscontains pinkpink toto orangeorange weatherinweatheringg chertchert •.... • • ••. 5555

/ 22.. Dolomite-darDolomite-darkk gray,gray, weathersweathers lightlight blue-grayblue-2'ray,, somesome bleaching.bleaching • • • • • • • • • • • • • • • • • • ••, . 3030

3.3. Limestone-bleachedLimestone-bleached white,white, granular,granular, recrystallized,recrystallized, witwithh portionsportions ofof darkdark graygray dolomitdolomitee whicwhichh havehave notnot beebeenn thoroughlythoroughly bleachedbleached,, tremolitetremolite inin dolomite,dolomite, somesome dolomitedolomite brecciabreccia bleachingbleaching decreasesdecreases upward.upward, • ••• . 210210

4.4. Dolomite-darDolomite-darkk gray,gray, weatheringweathering lighlightt hlue-gray,withblue-gray, with numerousnumerous breccibrecciaa zones,zones, somesome bleachedbleached zones,zones, bedsbeds ofof blacblackk dolomitedolomite prominenprominentt inin lastlast 8080 feet.feet. •. ••. . 155155

5.5. Dolomite-samDolomite-samee flSas HoHo.. 4,4, withwith dolomttedolomite exb"'ernelyextremely

brecciated,brecciated, andand withwith somesome chert .••• .. 00 o.... 0 • • • ••. 100100

6.6. Dolomite-darDolomite-darkk graygray,, weatherinweatheringg lightlight blueblue gray,gray, muchmuch dolomitedolomite breccia.breccia. • • • • • • • • • • •• . . 130130 7.7. Dolomite-darkDolomite-dark graygray,, weatherinweatheringg blackblack,, medium.­medium- grainedgrained,, laminatedlaminated withwith thinthin streaksstreaks ofof graygray coarse-grainedcoarse-grained dolomitedolomite •••••••••••• • • 4040

8.8. Dolomite-darDolomite-darkk gray,gray, weatheringweathering lightlight gray,gray, m~dium­medium- grained,grained , largelarge portioportionn covered,covered, dolomitedolomite brecciabreccia inin floatfloat • • 0o • • • • • • • • • • • • • • • • •• 160160

9.9. Dolomite-darkDolomite-dark gray,gray, weatherinweatheringg lightlight gray,gray, fine­fine­ grained,grained, laminated,laminated, thithinn chertchert bedsbeds andand somesome dolomitedolomite breccibrecciaa • • • • • • • • • • • • • • • ••• 175175 ..r-, 18

feetfeet 1100.. DoDolomite-alternatinl omite- alternatingg blueblue-gra- grayy weatheweatherinringg andand blacblackk lalaminateminatedd bebedsds,, whichwhich resembresembll ee ncurl"curlyy bed"bed" wherewhere fofoldedl ded,, bedss aboutabout I'1 ' thick,, somesome dolodolomitmitee bbrecciar e ccia,, bbranchinranchingg structuresstructures inin bblacl ackk dolodolomitemite,, ssomome chertchert . . • . . . . • • . . . • . . • • . .. 225225

FishFish Haven-LaketowHaven-Laketownn Contact?Contact? 11282800

1111.. CheCherr t zone-containzone- containss horhornn ccoraloral ss andand chertchert bebed 1100 ' t thickthick . . . • • • • . • • . • • • . • . . .. - 5555

1122.. DDolomite-mediuolomite-me diumm graygray,, weatherinweatheringg llighi ghtt graygray,, wiwitt hh HalysiteHa l y~lte8s spSf". andarid semisemi-globos- gl obosee formformss ooff brachiopodbrachiopodss iInn float.float. (fossifossnl outcrooutcropp nonott llocated.ocated.) ) • • • •• 3030 i 1133.. Dolomite-mediuDol om ite- me diumm gray,, weatherinwe atheringg llighi ghtt gray,, finefine-­ grainegrainedd . . . . • ...... • • • • . . . • . • . 111100

1144.. Dolomite-darDolomite- darkk gray,, weatheringg lighl i ghtt graygray/,, cherty.. 6060 1155.. DolomiteDolomite,, bleachebl eachedd white,, granulargranular, , sofsoftt • · . . . 4040 1616.. DolomiteDo l omite,, dardarkk gray,, weatheringg lighl ightt graygray,, chertchert,, soms omee dolomitdol omitee anandd cherchertt breccibreccia.a • • • • • . • • • 205205

1177.. Dolomite-mediuDol omite- mediumm graygray,, weatherinweatheringg lighlightt graygray,, withwith manmanyy bleachebl eachedd zoneszones.. • • • • • • • • • • • • • • • 235235 1818.. Dolomite-mediuDolomite- me diumm gray,, weatheringg lighlightt gray,, bebe-­ cominc omingg chertycherty. . • • • • • • • • • • • • • • • • • • 2211 0 Laketown-SevLaketown- Sevyy contacc ontactt 994455

1919.. Limestone-mediuLimestone- me diumm graygray,, weatherin"eather ingg lighlightt gragrayy toto creacreamm color, , somsomee platpl atyy bedbedss (4"" ttoo 1010"" thickthick)) smalsmalll amounamountt ooff pinpinkk cherchertt paralleparallell bedding,, veryvery fine-grainefine- grainedd witwithh conchoidaconchoidall fracture...... • • • • •. • 30300

20.. Covered-ScotiCovered- Scotiaa GulcGulchh . • • • • . • • .• • • • • •• 300300

2121.. Limestone-lighLimestone-lightt gragrayy dolomiticdo l omitic, , mostlmostl yy bbleacheleachedd whitewhite, , soms omee blubl uee gragrayy weatheringg dolomitedo l omite, , bbee-­ comingg mor moree prominenprominentt upwardd •••• • • • • . • • • • ••• 110000

Sevy-SimonSevy- Simonsons on ContacContactt 700\ 1919

feetfeet 22.22. Dolo!1'lite-darkDolomite-dark gray,gray, weatherinweatheringg blubluee graygray andand black,black, medium-grained,medium-grained, blacblackk laminatedlaminated bedsbeds 2'21 thickth ick,, becominbecom.ingg Hioremore prominenprominentt upwardupward.. SomeSome limestonelimestone bedsbeds • • • • • • • • • • • • • • • • • • 300300

23.23. SerneSame asas NoNo.. 2222,, witwithh chertchert bedsbeds andand chertycherty dolo­dolo­

mitimiticc limestone,limestone, ';'::;:";;";"';;~;;"";;';;;"';";'--:;:;'i::..f.CladoporCladoporaa spSD . af-at'.J tr,pto.I \,J p of'of...1. "n~tuniI..A..J,. t --:..~"'lI .z...n zonezone abouaboutt 1010 feetfeet thicthickk • • • • • • • • • • • • • 130130

Simonson-GuilmetteSimonson-Guilmette contactcontact 430430

24 .• DOlomite-lightDolomite-light blubluee gray,gray, calcareoucHlc~.reouss cleachedbleached whiwhit t ee inin manmanyy zones,zones, son:esome ververyy chert.ycherty ZOlJ.6S,zones, ClsdoporaCladopora sp.sp. 35'351 fromfrom toptop ofof unit.unit ...... • • • • • ••. 275275

2525.. QuartzQuartz ite-fineIte-fine ttoo coarse.-[re.icoarse-grained ned,, whitwhitee toto veryvery lightlight gray,gray, prominenprominentt beddingbedding,, somesome crossbedding,crossbedding, highlhighlyy fractured.fractured. (Allah(Allah quartzite)quartzite) •. • • • • •• 5050

26.26. Limestone-lir,htLimestone-light gray,gray, weatheringweathering lightlight blueblue gray,gray, platyplaty withwith irr6gul&rirregular triinthin whitwhitee calccalcit ite e bandingbanding parallelparallel beddingbedding,, becominbecomingg chertycherty andand dolomiticdolomitic upwarupvJardd •«..«....o...... • • 0 • • • • 0 • • • • • • • • • • • •. • 6060

27.27. Dolomite-darkDclomite-dark gray,gray, bleached,bleached, witwithh interbeddedinterbedded limestonlimestonee bedbedss 1 footfoot thick,thick, somesome chertycherty beds,beds, Endand poorlpoorlyy preservepreservedd herhornn coralscorals • • • • • • • • • 25025-0

OutcropsOutcrops mostlymostly coveredcovered byby e.lluvit.un.alluvium. 635635

CarboniferousCarboniferous SystemSystem.

Genera.lGeneral statenlEmtStaterne nt

SinceSince manymany ofof thethe outcropsoutcrops inIn thethe WestWest TinticTintic RangeRange failedfailed toto yiele'·yield fossils,fossils, anandd becausbec8.usee outcropsoutcrops I:'l'hichwhich werewere fossiliferousfossiliferous werewere seperatedseparated byby structuralstructural complicationscomplications andand byby extrusiveextrusive covercover,, a completecomplete sequencesequence ofof bedhedss waswas notnot workedworked out.out. DiagnostiDiagnosticc fossilsfossils foundfound indicatin~icAtee anan Upper- MississippianMisslssippian 2020 andand LowerLower PennsylvanlllDPennsylvania^ ageage forfor ;1"..uch,much, ifIf nonott allall,, ofof thethe

PaleozoicPaleozoic o1J.tcrops.outcrops. ':rhaThe G!'eatGreat 81ueBlue forr::8.tformatio ionn ofof UpperUpper

Mississippian¥Ississippian age;age; andand LoweTJowerr PennsylPennsylvanla vani~nn sedimentsedimentss equiv-equiv­ alentalent toto lowelowerr portionsportions ofof thethe Oqull"rhOquirrh formatiorlformation havhaves beenbeen recognized.recognised.

GreaGres t BluBIll.ee formatformat ionion

TheThe GreatGreat BlueBlue formetionformation h.~.shas beenboen identifiedidentified atat variousvarious localitieslocalities inin thethe WestWest 'T'inticTintic Ranp:e.Range. Loug}JlinLoughlin (1920,(1920, p.p. 438)438) foundfound fossilsfossils neanearr thethe rese~voi~reservoir a3tt thethe headhead ofof CherrCherryy Creek,Creek, whichwhich G.G. H.H. GirtyGirty regardedregarded asas UpperUpper HIssissippianMississippian.. NNoo diag-diag­ nosticnostic fossilsfossils werewere founofound byby thethe writerwriter inin thithiss areaarea whichwhich waswas mappedmapped asas undtfferentiated,undifferentiated, butbut possiblpossiblyy thethe GreatGreat BlueBlue formationformation outcropsoutcrops here.here.

TheThe GreatGreat BlueBlue limestonelimestone outcropoutcrop northnorth ofof ththee junctionjunction betweenbetween thethe EurekaEureka ro~droad andand VernonVernon CreekCreek roaroadd (See(See GeologicGeologic

Map)Map) hahass yieldeyieldedd horhor,nn coralscorals andand crlnoidcrlnoid columnalcolumnalss whichwhich serveserve toto identifyidentify itsits age.age.

TheThe followingfollowing sectionsection waswas measuredmeasured westwarwestwardd frofromm thethe

CherryCherry CreekCreek SummitSummit onon thethe EurekaEureka road.road. feetfeet 1.1. Limestone-darkLimestone-dark gray,gray, weatherinweatheringg blueblue gray,gray, 81slightl ightlyy sB.ndysandy Inin somesome bedsbeds • • • • • • • • . . . 150150

2.2. Limestone-likeLimestone-like No.1,No. 1, withwith so~esome smallsmall horhornn co~als,corals, andand witwithh thinthin sandysandy hedsbeds g:tvtne:giving a laminatedlaminated appearanceappearance toto we!theredweathered surfacesurface •...... • • • • • • ••. 150150 2121

feetfeet 3.3. Limestone-likLimestone-likee No.1,No. 1, becomingbecoming moremore sa.ndy,sandy, withwith oneone sandstonesandstone bedbed 8'3T thickthick atat thethe toptop ofof thethe unit ...... • ...... 4545 4.4. AlternatingAlternating sandysandy limestonelimestone andand calcareouscalcareous sand­sand­ stonestone bedsbeds uupp toto 2020 feetfeet thick,thick, sandstonesandstone bedsbeds formform ledges.ledges • • • • • • • • • • • • • • • • •• 150150

5. SameSame asas No.4,No. 4, withwith sandsand decreasing,decreasing, andand withwith fossiliferousfossiliferous limestonlimestonee containing-crinoidcontaining crinoid stemsstems andand hornhorn corals.corals • • • • • • • • • • • • • • •• 8080

6.6. Sandstone,Sandstone, highlyhighly calcareous,calcareous, witwithh sandysandy lime-lime stonestone atat thethe basebase ofof unit.unit • • • • • • • • • •• 8080

TotalTotal 655655 OverlyingOverlying formationsformations bleached,bleached, dolomitizeddolomitized andand jasperoidizedjasperoidized,, indicatingindicating faulting.faulting.

ApproximatelyApproximately 1,0001,000 feetfeet ofof blackblack shalesshales andand gray,gray, browbrownn weatherinweatheringg quartzitesquartzites formform thethe corecore ofof ththee MapleMaple PeakPeak anticline.anticline. NoNo fossilsfossils werewere foundfound iinn thesethese sediments,sediments, but,but, becausbecausee ofof itsIts apparenapparentt ~-.9-~[9I'~lllJ!~conformable __ !'~.l:!iiQ!LJLfJl_Qw_--th~LQFea..:t._relation below the Great ..

BlueBlue limestoneslimestones previouslypreviously described,described, plusplus a veryvery distinctdistinct lithologiclithologic similaritysimilarity toto thethe ChiulosChiulos membermember ofof thethe GreatGreat BlueBlue formationformation inin thethe TinticTintic districtdistrict,, itit isis herehere tentativelytentatively correlatedcorrelated withwith thatthat unitunit untiuntill furtherfurther fossilfossil evidenceevidence sub-sub­ stantiatesstantiates oror disprovesdisproves thethe theory.theory.

HaHall MorrisMorris hahass seenseen thithiss unitunit,, andand hashas shownshown thethe authorauthor thethe ChiulosChiulos membermember inin thethe field,field, andand thethe conclusionconclusion waswas reachedreached thatthat thesethese formationsformations areare equivalent.equivalent. TheThe ChiulosChiulos member,member, asas describeddescribed inin unpublisheunpublishedd literatureliterature byby membersmembers ofof 2222 ththee EurekaEureka brancbranchh ofof ththee GeologicalGeological Survey,Survey, Iiss 837837 feetfeet thickthick,, andand isis equivalentequivalent toto thethe LonLongg TraiTraill shaleshale membermember ofof thethe GreatGreat BlueBlue formationformation inin ththee OquirrOquirrhh mountains.mountains.

TheThe followingfollowing sectionsection inin thethe ChiuloChiuloss membememberr waswas measuredmeasured westwardwestward alongalong ththee EurekaEureka roadroad belobeloww ththee Devil'Devil'ss GateGate Con-Con­ glomerateglomerate outcrop:outcrop: feefeett 1.1. Shale-black,Shale-black, dense,dense, ververyy fissilefissile anandd papery,papery, some­some­ timetimess fracturinfracturingg intointo smoothsmooth conchoidalconchoidal nodules.nodules. •. 280280

2.2. Quartzite-gray,Quartz ite-gray, weatheringweathering graygray ttoo greenishgreenish brown,brown, finefine grained,grained, withwith bedbedss approximatelyapproximately 1 footfoot thickthick,, containscontains somesome interbeddedinterbedded shaleshale andand brownbrown sandysandy bedbedss • • • • • • • • • • • • • • • • • • • • 185185

33.. MucMuchh thethe samesame asas NoNo.2,. 2, witwithh shaleshale anandd sandysandy lithologlithologyy increasingincreasing upwarupward.d • • ••••• • • 340340 4.4. Shale-black,Shale-black, weatherinweatherineg brownbrown,, witwithh mucmuchh blackblack carbonaceouscarbonaceous mattenatterr Iinn somesome bedbedss •...... • • • • • • •. • 100100

5.5. Quartzite-grayQuartzite-gray toto blackblack,, bedbedss aboutabout l'I1 thick,thick, weatherweatherss gray,gray, andand formsforms a sharpsharp verticaverticall ridgeridge betweenbetween ththee softersofter shales.shales • • • • • • • • • • •• 2525

6.6. Shale-blackShale-black,, paperpaperyy samsamee asas NoNo.1,. 1, witwithh inter-inter­ beddebeddedd brownbrown,, graygray andand blacblackk quartzitquartzitee bedbedss de­de­ creasing, upward.upward. •. • • • • • • • • • • • • • • •• 210210

TotalTotal 11401140' '

FossilsFossils havhavee beebeenn foundfound inin thethe smallsmall GreatGreat BluBluee lime-lime­ stonestone outcropoutcrop easteast ofof ththee PrecambrianPrecambrian klippeklippe neanearr McIntyreMclntyre

RanchRanch.. HornHorn coralscorals,, includingincluding FaberophyllumFaberophyllum SP.,sp., araree abundant.abundant.

DrDr.. StokesStokes statesstates thatthat thesethese fossilsfossils indicateindicate thatthat thethe formationformation 23 isis "almost"almost surelysurely GreatGreat BlueBlue inin age-lowerage-lower part?"part?"

MississippianMississippian undifferentiatedundifferentiated

WestWest ofof ththee CherryCherry Creek-VernonCreek-Vernon CreekCreek summitsummit anandd northnorth ofof ththee highighh limestonelimestone ridgeridge therethere,, a thinthin beddedbedded,, platyplaty lime­lime­ stonestone containingcontaining a lightlight yellowishyellowish,, argillaceousargillaceous materialmaterial onon thethe beddingbedding planesplanes marksmarks thethe foldingfolding inin thatthat area.area. TheThe formationformation isis lithologicalllitbologi~allyy similarsimilar ttoo ththee OpohongaCpohonga lime­lime­ stonestone andand PinyonPlnyon PeaPeakk limestonelimestone ooff ththee Tinti.eTintic dist!'ict.district. TheThe onlyonly fossilfossil founfo'~ndd inin thethe formationformation wawass a coiledcoiled gastropodgastropod similarsimilar toto EuomphalusEuomphalus sp.,sp., Whichwhich isis probablprobablyy MississippianMIssissippian. inin age.age. SouthwardSt)uthward,, structuralstructural complicatlonscomplications werewere encountered,encountered whicWhichh terminateterminatedd furtherfurther calculationcalculation ofof sequence.sequence. HornHorn coralscoral ofof MississippianMIssissippian (?)(?) ageage werewere foundfound inin ththee sandsandyy limestonelimestone

0non ththee southsouth sideside ofof thethe highighh ridge~idge.. UntiUntill structuralstructural prob­prob­ lemslems areare solvedsolved inin thisthis area,area, andand mormoree dlagnosticdiagnostic fossilsfossils areare found,found, thithiss outcropoutcrop ofof limestoneslimestones wilwilll bebe tentativelytentatively designateddesignated asas MississippianMississippian undifferentiateundifferentiatedd limestones.limestones.

OquirrhOquirrh formationformation

AnAn isolatedisolated exposureexposure ofof 8haly,shaly, mediummedium gray,gray, blubluee graygray weatheringv/eathering limestonelimestone jusjustt northnorth ofof thethe redred conglomerateconglomerate out­out - cropcrop onon ththee EurekaEureka roaroadd hashas yieldedyielded thethe followingfollowing fossilfossil assemblageassemblage:: 2424

CupCup CoralsCorals

CrinoiCrinoidd dolumnalsdol urn rials

SchizophoriaSchlzophoria texanatexana

LinoproductusLinoproductus cf.of. L.L. prattenianusprattenlanus

ChonetesChonetes sp.sp.

SpiriferSplrlfer rockyrocky montmontanu anuss

SpiriferSpirifer occidentalisoccidentalis

DictyoclostusDictyoclostus cf.cf. D.D. hermosianushermosianus

Buxtonia?Buxtonia?

Composita?Composita?

Dr.Dr. StokesStokes statesstates thatthat thisthis assemblageassemblage indicateindicatess earlyearly

PennsylvanianPennsylvanlan ageage appropriateappropriate toto thethe lowerlower OquirrOquirrhh formation.formation.

UnfortunatelyUnfortunately ~histhis fossiliferousfossil iferous formationformation hahass beenbeen

isolatedisolated bbyy faultingfaulting toto thethe south,south, andand isis coveredcovered bbyy extru­extru-

sivessives toto thethe north,north, andand itsits relationrelation toto overlyingoverlying andand under­under­ lyinglying stratastrata couldcould nonott bebe workedworked out.out.

TheThe largelarge OquirrhOquirrh formationformation outcropoutcrop itnn thethe southern-southern­ mostmost WesWestt TinticTintic containscontains manymany structuralstructural complicationscomplications whichwhich

werewere notnot solvedsolved inin thisthis study.study. OnlyOnly a veryvery fefeww poorlpoorlyy pre-pre­

servedserved fossilsfossils werewere found,found, includingincluding somesome badlybadly distorteddistorted

ProductidProductid brachiopodsbrachiopods ofof LateLate MississippianMIssissippian oror EarlEarlyy PennsylvanianPennsylvanlan

age.age. IfIf thethe structurestructure isis simplesimple foldingfolding asas mappedmapped,, thenthen anan

OquirrhOquirrh ageage isis valid.valid. FaultingFaulting isis suspected,suspected, howeverhowever,, toto

complicatecomplicate thethe structurestructure here.here. 2525

CretaceouCretaceouss SystemSystem

Devil'sDevil's GateGate conglomerateconglomerate

MesozoicMesozoic historyhistory isis representedrepresented onlyonly byby a smallsmall outcropoutcrop ofof reredd conglomerate,conglomerate, madmadee uupp ofof angulaangularr ttoo subangularsubangular frag­frag­ mentmentss ooff graygray PaleozoicPaleozoic limestones,limestones, whichwhich areare anan averageaverage ofof

1"1M toto 33ft" inin diameter,diameter, withwith somesome blocksblocks upup toto 22 feetfeet inin dia-dia­ metemeterr (Plate(Plate IVIV,, B).B). TheyThey araree wellwell cementedcemented inIn a reredd c81-cal­ cereouscareous matrix.matrix.

SinceSince veryvery littlEllittle quartzitequartzite occursoccurs inin ththee formation,formation, andand nonenone resemblingresembling PrecambrianPrecambrian quartzitquartzitee waswas found,found, itIt isis logicallogical toto assumeassume anan agagee olderolder thanthan thethe perioperjodd ofof thrusting,thrusting,

sincesince ththee thrustthrust atat oneone timtimee extendedextended overover thisthis areaarea., Also,Also,

Itit restrestss unconformablunconformablyy uponupon rocksrocks ofof UpperUpper I/;ississlppianMIssissippian ageage anandd !sis overlainoverlain hyby extruRivesextrusives ofof EoceneEocene ageage (Plate(Plate IV,IV, A).A).

ItIt 1sis possiblpossiblee thathatt thisthIs formationformation representsrepresents debrisdebris derivedderived fromfrom ththee foldingfolding Pal,eozoicPal.eozoic sedim.6ntssediments priorprior toto thrustthrusting inc;,, andand

P'l.symay bbee equiva.lentequivalent ttoo ththee IndianolaIndianola (?)(?) sedimentssediments ooff ththee CanyonCanyon

RangeRange describeddescribed byby ChristiansenChristiansen (1952,(1952, p.p. 725).725).

QuaternaryQuaternary SystemSystem

QuaternaryQuaternary colluviumcolluvium

SlopesSlopes ofof manmanyy ofof thethe lowerlower ridgeridgess areare coveredcovered byby aa

thicthickk depositdeposit ofof materialmaterial Whichwhich hashas beebeenn shedshed fromfrom thethe PlatPlate© IV

PI die mA

A. ViewView lookinlooki ngg north atat DeviDevil'l'ss GGatatee conglomerateconglomerate rrestinestingg unconformablunconformablyy upoupon sshalehaless anandd quartzitesquartzites ooff UUppepperr MHississippiaississippiann aagege ..

B. VieVieww sshowinhowingg llargargee angularangular frafragmentgmentss ofof PaPaleozoil eozoicc llimestoneimestoness i n tthhee DDevil'evIl'ss GateGate coconglomeratengl omerato.. 2626 adjoiningadjoining higherhigher peakpeakss andand ridgesridges.. ThisThis isis especiallyespecially promi­promi­ nentnent iinn CherryCherry CreekCreek Cs.nyanCanyon wherewhere debridebriss fromfrom Me.pleMaple PeakPeak andand thethe higherhigher peakspeaks ofof thethe 'NestWest TintiTinticc RangRa.ngee hashas obscuredobscured muchmuch ofof ththee structurestructl~e.. A fewfew recentrecent landslideslandslides werewere alsoalso notednoted inin thisthis area.area.

Quaternar'YQuaternary pedimentpediment gravelsgravels

A conspicuousconspicuous highighh levellevel surface,surface, slopingsloping gentlygently awayaway fromfrom ththee mountaimountainn ranges,ranges, representsrepresents a dissecteddissected pedimentpediment sur-facesurface formedformed atat somesome earlearlie ierr time.time. TheThe sedimenta.rysedimentary depositdeposit consistsconsists ofof poorlypoorly sortedsorted andand poorlpoorlyy roundedrounded pebblepebbless andand cobblecobbless ooff quartzitquartzitee limestonelimestone andand igneousigneous rocksrocks,, withwith finer.finer, clasticselastics fillingfilling ththee interstices,interstices, andand weaklweaklyy heldheld togethetogetherr byby a calcarceouscalcarceous cement.cement. T~eThe depositdeposit isis wedge-shaped,wedge-shaped, andand thickensthickens mountainward.mountainward.

QuaternaryQuaternary alluviumalluvium

QuaternaryQuaternary alluviumalluvium consistsconsists ofof thethe finerfiner sandssands andand siltssilts whicwhichh occupyoccupy thethe extremeextreme bottombottomss ofof thethe smallsmall valleys,valleys, derivedderived iinn a largelarge parpartt fromfrom dissectiondissection ofof thethe previouslpreviouslyy des­des­ cribedcribed pedimenpedimentt surface.surface. BelowBelow ththee reservoir,reservoir, CherryCherry CreekCreek hahass cutcut deeplydeeply intointo thesethese alluvialalluvial deposits,deposits, probablprobablyy duduee toto recenrecentt rejuvenation.rejuvenation. IGNEOUSIGNEOUS ROCKSROCKS

IntrusiveIntrusive RocksRocks

TheThe largelarge intrusionintrusion inin thethe WestWest TinticTintic MininMiningg DistrictDistrict hashas beenbeen describeddescribed byby LoughlinLoughlin (1920,(1920, pp.. 436)436) asas a "stock-"stock­ likelike bodybody ofof monzonite."monzonite." ItsIts arealareal extentextent isis uncertain,·uncertain,' sincesince iitt iiss coveredcovered ttoo thethe southsouth bbyy QuaternaryQuaternary pedimentpediment ( gravels.gravels. ItIt hahass beebeenn suggestedsuggested bbyy StringhamStrIngham (1942,(1942, pape.. 274),274), thatthat ththee intrusionintrusion isis quitequite largelarge andand extendsextends somesome distancedistance southwardsouthward beneathbeneath ththee alluvialalluvial cover.cover.

TheThe abundanceabundance ooff smallsmall intrusivesintrusives andand ththee mineraliza-mineraliza­ tiontion andand bleachingbleaching ooff sedimentarysedimentary rocksrocks atat somesome distancdistancee fromfrom thethe monzonitemonzonite outcropoutcrop givesgives riserise ttoo thethe suspicionsuspicion thatthat thethe mainmain intrusionintrusion underliesunderlies mucmuchh ofof thethe mininminingg districtdistrict atat nono greatgreat depth.depth.

TheThe monzonitemonzonite isis graygray toto gray-green,gray-green, andand weatherweatherss tantan toto lightlight gray.gray. IItt isis even-grained,even-grained, withwith pinkpink orthoclaseorthoclase andand latheslathes ofof plagioclasplagioclasee identifiableidentifiable inin hanhandd specimen.specimen. PlatesPlates ofof biotitbiotitee andand euhedraleuhedral hornblendhornblendee cryetalscrystals uupp ttoo one-eighthone-eighth ofof anan inchinch longlong areare ahundant.abundant.

InIn additionaddition ttoo thethe monzonite,monzonite, severalseveral smallersmaller intrusivesintrusives cutcut bothboth PaleozoicPaleozoic anandd PrecambrianPrecambrian strata,strata, thethe largestlargest ooff thesethese beinbeingg thethe largelarge oval-shapedoval-shaped granitegranite porphrporphryy bodbodyy northeasnortheastt ofof thethe OrienOrientt minemine andand thethe granitegranite porphrporpbryy atat thethe OroOro PlataPlata mine.mine.

2727 2288

OtheOtherr smallsmall dikedtkess anandd apophysesapophyses ofof dioritediorite andand apliteaplite inin composition,composition, araree alsoalso present.present.

Stringhastringhamm (1942(1942,, pp.. 290290)) presentpresentss evidenceevidence ttoo supportsupport a theorytheory ofof a slowlyslowly coolingcooling f:lag-rnamagma ofof mO!lzoniticmonzonitic composition.composition.

AAtt intervalintervalss duringduring ththee coolincoolingg process,process, successivesuccessive differen-differen­ tiatetiatess ofof increasinincreasin.gg silicasilica contencontentt werweree intrudedintruded intointo thethe

/ countrcountryy rockrock.. ThThee finafinall stagesstages ofof thithiss processprocess occurredoccurred withwith z ththee injectioinjectionn ofof aplitaplitee anandd quart-baritequart-barite dikesdikes followefollowedd byby .\ metamorphismmetamorphism anandd mineralization.mineralization.

A descriptiondescription ofof petrographpetrographyy a.ndand mineralizatiomineralizationn inin thethe

WesWestt TinticTintic MininMiningg DistricDistrictt hahass beebeenn madmadee byby StringhamStringham (1942).(1942)•

ExtrusivExtrusivee RocksRocks

ExtrusiveExtrusive rockrockss covercover approximatelyapproximately 1818 squarsquaree milesmiles ofof ththee areareaa ooff studystudy.. RhyoliteRhyolitess covercover ththee largeslargestt portionportion,, withwith significantsignificant amountamountss ooff latiteslatites anandd andesiteandesitess inin ththee southernsouthern partpart.. AlAlll s6mplessamples shoshoww extensiveextensive weatheringweathering,, witwithh ththee feld-feld­ sparsspars especiallyespecially disintegrated.disintegrated.

ThThee rhyolitrhyolitee inin generalgeneral lSis weathereweatheredd whitewhite,, ana.ndd contalnscontains largelarge amountsamounts ofof quartzquartz whicwhichh cacann bbee easileasilyy identifieidentifiedd inin handhand sample.sample. A rhyolitrhyolitee samplesample takentaken fromfrom WesWestt CherryCherry CreekCreek ValleyValley consistedconsisted ofof approximatelapproximatelyy 25%25$ quartquartzz andand 4040%$ pinplnkk orthoclase.orthoclase.

ThinThin sectionsectionss showshow thethe phenocrystphenocrystss ttoo bbee badlbadlyy fractured,fractured, indicatinindicatingg movemenmovementt ofof thethe partiallpartiallyy crystallizedcrystallized flowflow 2929

(Plate(Plate V).V). NearNear thethe contactcontact fragmentsfragments ofof shaleshale andand ququartzitartzitee areare commoncommon asas inclusionsinclusions inin thethe flows.flows.

AnotherAnother typetype ofof rhyoliterhyolite 1nin WestWest CherCherrr y CreekCreek ValleyValley isis thethe purplpurplee flowflow whichwhich formsforms thethe "chicken"chicken rock"rock" westwest ofof HasselHassel's1

Ranch.Ranch, ThisThis flowflow isis characteristicallycharacteristically platyplaty witwithh alternatinalternatingg purplepurple and whitewhite plates.plates. ItIt 1sis ggenerallenerallyy veryvery fine-grainedfine-grained toto gglassylassy,, withwith smallsmall intenselyintensely weatheredweathered phenocrystsphenocrysts ofof fefeldspaldsparr .

A larlarggee partpart ofof thethe southernsouthern areaarea 1sis coveredcovered byby a graygray andesitee flow.flow. TheThe plagioclasplagioclasee 1sis andesine,andandesine, and ggenerallenerallyy occursoccurs inin wewell-formell-formedd llathesathes.. EElongatel ongate,, auhedraleuhedral phenocrystsphenocrysts ofof hornbhornblendlendee showshow a preferrepreferredd orientationorientation..

ExceptExcept forfor fieldfield relationships,relationships, nono detaileddetailed studystudy ofof extrusivesextruslves 1nin thethe EastEast TlntlcTintic MMountainountainss wawass made , butbut a veryvery noticeablenoticeable resemblanceresemblance toto thethe extrusivesextruslves ofof thethe WWesestt TinticTintic

DistrictDistrict exists.exists.

ItIt 1sis probable"e thatthat thethe extrusivesextruslves inin thethe twotwo areasareas werewere extrudedextruded durinduringg" thethe samesame periodperiod ofof vuvulcanismlcanism.. HalHal MMorriorr iss

(personal(personal communication)communication) statesstates thatthat thethe extrusivesextrusives inIn thethe J , EastEast TinticTintic MMountainountainss havehave beenbeen veryvery accuratelyaccurately dateddated asas rIll^ -

"late"late middmiddllee toto earlyearly upperupper Eocene"Eocene" 1nin aagege.. PlatePlate V

PhotomicrographPhotomicrograph ofof rhyoliterhyolite flowflow fromfrom WestWest CherryCherry CreekGreek Valley,Valley, showingshowing fracturedfractured phenocrystsphenocrysts ofof quartzquartz andand orthoclase.orthoclase.

X 100100 • • Platnatee VIVI

PhotomicrograpPhotomicrographh ooff andesitandesitee flot loww inin southersouthernn WesWestt TintiTlntlcc ValleyValley,, showInshowingg largl argee euhedraeubedrall phenocrystphenocrystss ofof hohornr n­­ blendblendee 1nin a finefine-graine- grainedd ggroundmassroundmass ..

X 100100

STRUCTURESTRUCTURE

RegionalRegional StructureStructure

InIn generalgeneral thethe structurestructure ofof thethe regionregion consistsconsists ofof foldedfolded PaleozoicPaleozoic formationsformations exposedexposed beneathbeneath ProterozoicProterozoic quartzitesquartzites andand argillitesargillites whichwhich composecompose ththee allochthonallochthon ofof thethe WestWest TinticTintic thrust.thrust. SomeSome shearshear faultingfaulting occurreoccurredd alongalong withwith thethe foldingfolding andand thrusting.thrusting. TheseThese structuresstructures havhavee beenbeen cutcut byby intruslves,intrusives, coveredcovered byby extrusives,extruslves, anandd havhavee beenbeen furtherfurther modifiedmodified byby BasinBasin andand RangeRange faultsfaults ttoo producproducee thethe presenpresentt northnorth trendingtrending ranges.ranges.

FoldsFolds

Brown'sBrown's RidgeRidge homoclinehomocline

DifferentDifferent interpretationsinterpretations ofof thethe structurestructure inin ththee WestWest

TinticTintic MiningMining DistrictDistrict havhavee beenbeen made.made. LoughlinLoughlin (1920,(1920, pp.. 437)437) inin hishis investigatio~investigation ofof thethe PaleozoicPaleozoic limestoneslimestones andand dolomitesdolomites ofof thethe WestWest TinticTintic MiningMining DistrictDistrict postulatedpostulated tightightt folding.folding.

HeHe states:states;

TheThe availableavailable datadata suggestsuggest a majormajor anticlineanticline withwith nearlynearly verticalvertical limbs,limbs, whosewhose axiaxiss isis aboutabout halfwahalfwayy betweenbetween thethe middlemiddle ooff thethe limestonelimestone areaarea andand itsits easterneastern contaccontactt withwith ththee quartzitequartzite series.series.

StringhamStringham (1942,(1942, p.p. 272)272) interpretedinterpreted ththee structurestructure toto bebe a steeplysteeply dippingdipping homoclinehomocline withwith overturningoverturning evident.evident.

3030 3131

However,However, nnoo evidenceevidence wawass foundfound toto indicatindicatee whicwhichh parpartt waswas

overturned.overturned.

EvidencEvidencee discovereddiscovered durinduringg thithiss studstudyy indicateindicatess thethe

northernorthernn parpartt iiss overturnedoverturned.. ThThee dipdip ooff ththee dolomitedolomitess form­form­

iningg Brown'sBrown's RidgRidgee increasesincreases fromfrom 6060 degreedegreess ttoo ththee easteast atat

ththee southersouthernn endend,, ttoo verticaverticall iinn ththee centracentrall portionportion,, anandd thenthen

ttoo aann overturneoverturnedd positiopositionn ooff 6060 degreedegreess ttoo ththee weswestt aatt thethe

northernnorthern enendd ooff ththee ridgeridge.. (Plat(Platee IIII,, B.B.,, anandd SectionSection BBEB'' ofof

GeologiGeologicc Map,Map.)) SinceSince ththee EurekEurekaa quartzitequartzite ooff 1IiddleMiddle OrdovicianOrdovician

ageage cropscrops ououtt ttoo ththee weswestt ofof Brown'Brown'ss RidgeRidge,, andand UppeUpperr Ordovician,Ordovician,

SiluriaSiluriann anandd DevoniaDevoniann rockrockss havhavee beebeenn founfoundd easeastt ooff ththee ridge,ridge,

iitt iiss apparenapparentt thathatt youngeyoungerr bedbedss araree crossecrossedd iinn anan easterlyeasterly

directiodirectionn andand thethe northernorthernn portioportionn ofof ththee exposedexposed structurestructure hashas beebeenn overturned.overturned.

ThThee westerlwesterlyy continuatiocontinuationn ooff ththee foldfold isis terminateterminatedd atat

thethe monzonitmonzonitee contact,contact, andand onon ththee easeastt ththee PaleozoiPaleozoicc sedimentssediments

araree hiddehiddenn bbyy quartzitquartzitee anandd argillitesargillites ooff ththee WesWestt TinticTintic

allochthon.allochthon.

MaplMaplee PeakPeak anticlineanticline

TheThe structuresstructures ofof ththee WesWestt TinticTintic MountainMountainss araree mostlymostly

coveredcovered bbyy debrisdebris shedshed frofromm PrecambrianPrecambrian quartzitequartzitess oonn thethe

higherhigher partpartss ooff ththee WesWestt TintiTinticc MountainsMountains.. HoweverHowever,, hogbackhogback

ridgeridge forminformingg quartzitequartzitess alternatinalternatingg witwithh blacblackk shaleshaless westwest

ofof Devil'sDevil's GateGate,, tractracee outout ththee nosnosee ofof ththee northward-plungingnorthward-plunging PlatePlate VIIVI--I.- ,

A. View l ooking south along the axia of the l!aple Peak Anticline. Maple Peak i8 in the background.

B.. VieVieww showingg quartzitquartzitee bedbedss overturneoverturnedd iinn corcoree oorf ththe i'-aplMapl ee PeaPeakk AAnticlinenticline.. PlatPlate e VIIVIIII

-~-- --

A.. VieVieww showinahowingg minominorr anticlinaanticlinall folfoldd iinn quartzitess inIn ththee ?M<;aplapl ee PeaPe~~k antianticlinecline..

"

I

-- BB.. ViewView llookinookingg northnorth atat f08s1fossiliferou11ferotlss llimestoneimestones ofof LowerLower PennsylvanianPennsylvanlan aaggee exexposeposedd bElDeathbeneath EoEocencenee extrusivextruslveses.. 3232 • anticline,anticline, andand indicateindicate thethe proprobablbabl ee structurestructure ofof thethe WestWest

TlntlcTintic MoMountainsuntains.. OneOne espeespeciallciallyy proprominenminentt ridridgge forminformingg quartzitequartzite 1nin thethe corecore ofof thisthis structurestructure oancan bebe identifiedidentified onon bothboth lilimbmbes ofof thethe anticline,anticline, andand showsshows itit toto bebe essentialessentialll yy anan overturnedoverturned isoclinalIsoclinal fofoldl d,, withwith bbotothh limbslimbs dippingg approximatelyapproximately 4545 degreesdegrees toto thethe easteast (Plate(Plate VII,VII, A.)A.).. CrossCross beddin,gg andand gradedgraded beddingbedding showshow thatthat thethe westernwestern 11limmbb isis thethe overturnedoverturned 11mb.limb. Minorr dragdrag foldsfolds andand fracturingg areare commoncommon 1nin thethe in­In­ competentcompetent blackblack shales.shales. Wes.t;wWestwarardd fromm thethe ·anticlinalanticlinal axisaxis thethe overturnedoverturned 11limmbb gradugraduallallyy steepens,steepens, andand f1nallyfinally assumesassumes aa normalnormal position,position, dippingg 3030 degreesdegrees ttoo thethe west.. TheThe westernwestern

11mblimb 1eis cutcut byby thethe VernonVernon CreekCreek fault,fault, andand thethe easteeasterrnn 11mblimb 1sis coveredcovered byby 8xtruslv8sextruslves (see(see crosscross sBctionsection AAAAt1 PlatPlatee XII).XII).

MclntyrMcIntyree ValleValleyy foldsfolds

WestWest ofof ththee VernoVernonn CreeCreekk fault,fault, aatt ththee CherrCherryy CreekCreek­-

VernonVernon CCreer eekk divide,, .-ththee Ilimeston imestonee bedbedss araree foldedfolded intintoo aa synclinesyncline andand adjoiningg anticlineanticline. . TheThe synclinesyncline plunplungegess approximatelyapproximately 3030 degreesdegrees ttoo ththee nortnorthh undeunderr ththee alluvium.alluvium.

TheThe synclinsynclinee ' formformss a topographictopographic,, canoe-shapedcanoe-shaped,, synclinasynclinall valleyvalley, , ththee corecore ooff whicwhichh hahass beebeenn erodeerodedd ououtt ooff a shashall yy limestonl imestonee ofof MississippianMIssissippian agea ge.. ThThee anticlinanticlinee iiss onlonlyy partlypartly exposeexposedd jusjustt easeAstt ooff ththee WesWestt CherrCherryy CreeCreekk summit;; howeverhowever,, herheree ththee shalshalyy limestonlimestonee bedbedss araree seeseenn ttoo ,wrawrapp arounaroundd thethe northward-plunginnorthward-plungingg nosnosee ooff ththee anticline.anticline.

~. • 33

Determininf~Determining thethe naturnaturae ooff thesethese structuresstructures cacann hestbest bebe accomplishedaccomplished inin ththee shelyshaly limestone.limestone. ThThee highighh easteast trendingtrending ridgeridge whicwbiohh isis parpartt ooff ththee foldedfolded beltbelt isis cappedcapped byby a dolomitedolomite

thrustthrust breccia,breccia, whicwhichh obscuresobscures thethe folds.folds.

FoldsFolds inIn thethe southernsouthern Wes~estt TlnticTintic areaarea

AsAs hashas beenbeen mentioned,mentioned, structurestructuress inin ththee Oqui~bOquirrh forma-forma­ tiontion atat thethe southernsouthern end. ooff ththee WesWestt TlnticTintic MountatnsMountains areare

somewhatsomewhat uncertair,uncertain, dUedue ttoo possiblpossiblee faultingfaulting inin thethe shaleshale beds.beds. AsAs determineddetermined byby dipsdips andand strIkes,strikes, thethe structurestructure seemsseems toto bebe simileI'similar toto thathatt ofof thethe MclntyrMcIntyree ValleyValley foldsfolds anandd r,]apleMaple

PeakPeak anticlineanticline ttoo ththee northnorth,, witwithh anan anticlineanticline andand adjoiningadjoining synclinesyncline containingcontaining ~inorminor warpswarps andand flexures.flexures.

FaultsFaults

WestWest Tinti~intioc thrustthrust

Lougr:linLoughlin (ln2(1920n , p.p. 438408)) firstfirst notednoted andand describeddescribed thethe discordantdiscordant relationrelation betweebetweenn thth3e u';)tu.rned,upturned, northward-strlktngnorthward-striking limestonelimestone ant"rldd dolomitedolomitess andand tbothe overlyingoverlyin[~,, relativelrel~itlyelyy gently-gently- dippinedipping shalesshales andand quartzquartzite ito.. HF'3e mentionsmentions,, inIn additadditio i0nn toto manymany examplesexamples ofof discordanoe,discordance, that,that,

ToTo regardregard thethe contaci:;contact asas aRnn unconformitunconformityy wouldwould :16cessarilynecessarily implyimply anan immenseimmense thicknessthickness ofof PrecambrianPrecambrian limestonelimestone tnin thothe ';,'estWest TlnticTintic districtdistrict andand nowherenowhere elseelse iinn ththee GreatGreat BasiRasinn region.region.

TheThe basbasee ofof thethe thrustthrust isIs welwelll exposedexposed inin ththee WestWest TlntlcTintic 3344 districtdistrict.. FurtheFurtherr nortnorthh anandd easeastt ththee actuaactuall thrusthrustt contactcontact iiss obscureobscuredd bbyy alluviualluvi1.L.'11m anandd extrusives.extruslves.

ThThee thrusthrustt planplanee iinn ththee WesWestt TintiTinticc districdistrictt dipdipss north-north­ warwardd aatt varyinvaryingg loloww anglesangles.. HoweverHowever,, furthefurtherr nortnorthh ththee dipdip iiss generallgenerallyy abouaboutt 2255 degreedegreess ttoo ththee westwest.. ThThee chaotichaoticc dips,dips, togethetogetherr witwithh ththee pre-thruspre-thrustt relierelieff aass indicateindicatedd bbyy ththee ex­ex- \ poseposedd limestonlimestonee ridgesridges,, supporsupportt Stringham'Stringham'ss explanationexplanation

(1942,(1942, pp.. 273)273),, thathatt ththee surfacsurfacee oveoverr whicwhichh ththee PrecambrianPrecambrian bedbedss werweree thrusthrustt wawass a ververyy irregulairregularr oneone,, anandd ththee intenseIntense brecciatiobrecciationn anandd slickensidinslickensidingg ooff ththee quartzitquartzitee Ilss duduee toto theitheirr constanconstantt adjustmenadjustmentt ttoo ththee underlyinunderlyingg topography.topography.

EvidenceEvidence thatthat ththee thrusthrustt sheetsheet originalloriginallyy extendedextended overover thethe entireentire regioregionn isis abundant.abundant. PrecambrianPrecambrian quartzitequartzite capscaps

MapleMaple MountaiMountainn andand alsoalso thethe lowerlower hillhillss toto ththee south.south. TheThe highhigh limestonelimestone ridgesridges atat thethe CherryCherry CreekCreek summitsummit areare cappedcapped byby dolomitedolomite andand jasperoijasperoidd brecciabreccia,, whicwhichh HalHal MorriMorriss (personal(personal communication)communication) identifiesidentifies asas a "sole"sole breccia.breccia."" TheThe hiFherhigher ridgeridge actuallyactually hashas a smallsmall remnantremnant ofof quartzitequartzite restingresting onon thethe breccia.breccia. GreatGreat hlocksblocks ofof thoroughlythoroughly brecciatedbrecciated andand recementedrecemented quartzitequartzite scatteredscattered overover thethe regionregion attestattest toto thethe formerformer presencepresence ofof thethe thrustthrust sheet.sheet. TheThe PaleozoicPaleozoic sediments,sediments, too,too, areare inIn manymany areasareas badlybadly brecciated,brecciated, indicatinrindicating thatthat thethe thrustthrust planeplane waswas formerlyformerly notnot tootoo farfar aboveabove thethe presentpresent exposedexposed erosionerosion surface.surface.

\ 35

ThThee agagee of th t hee thrustingg iiss somewhatsomewhat unceuncertainrtain..

ChristianseChr i stiansenn (1952(1952,, p.. 732732)) assignass i gnss ththee CanyonCanyon RangRangee thrustthrust­­

ing t oo EarEarllyy CretaceousCretaceous.. EardEardlel eyy ((19511951,, pp.. 272733 anandd 325325)) hhaass useusedd thothe term,, "Ceda "Cedar HillHillss orogenyorogeny"" for thithiss Cretaceouss dis­dis­ turbance,, bubutt placeplacess itit iinn MiddlMiddlee CretaceouCretaceouss time,, ththee datingdating ooff thethe orogenyorogeny beinbei ngg dependendependentt upouponn ththee agagee ooff ththee IndiIndlanol, anolaa group.. TentativeTentative ddatinatingg ooff ththee 'NWesestt TTinti1nttoc thrustthrust,, iinn thisthis paperpaper,, wilwilll bbee MiddlMiddlee CrCretaceousetaceous ..

ActuaActuall ffaulaultt movementmovement cannotcannot bbee accuratelaccuratelyy ccalculatedalculated,, butbut a cconsiderablonsiderablee horizontahorizontall movemovemenmentt iIss showshownn bbyy ththee presencepresence ofof PrecPrecambriaambriann remnantremna ntss IInn ththee WesWestt TintiT1nttoc RangeRange..

VernoVernonn CCreer eekk faultfault

ThThee strstraigha i ghtt escarpescarpmenmentt formingg ththee easteasterernn edgedgee ofof

MMclntyrcIntyree ValleVa lleyy markmarkss ththee tracee ooff a8 larglargee nortnorthh ttrendinrendingg ffaulaultt ooff ththee BasiBasinn aanndd RangRangee type.. ThisThis faulfaul tt iiss aann especiaespeciallllyy prominenprominentt featurfeaturee onon,aeria. aeriall photographsphotographs,, wherwher ee itt caCBnn bee tracedtraced northward. . Itss existencexistencee southwardsouthward inIn CherrCherryy CreeCreekk ValleValleyy isis obscureobscuredd bbyy thicthickk alluviaalluviall covercover..

SinceSince ththee GreatGreat BluBl uee foformatior mationn iiss inin faulfaul tt contaccontaott withwith olderolder MIssissippiaMississippiann bebeddss aatt ththee CherrCherryy CCreek-Vernoreek- Vernonn CrCreeeekk dividedivide,, ththee westernwestern blocb l ockk witwithh ththee oldeolderr fformationor mationss mmusust bebe thethe up-throwupthrownn blocbl ockk ttoo eexplaixplainn tthhee sequesequencncee ooff beds.. TheThe sscarcarpp formingg ththee westerwesternn edgeedge ofof MclntyrMcIntyree ValleValleyy wouldwoul d,, thethereforerefore,, bbee anan obsoquenobsequentt faultt scarpscarp.. PlatPlatee IXIX

VieVieww lookinlookingg northnorth aatt ththee basbasee ofof ththee WesWestt TintiTinticc thrusthx'ustt iinn thethe

ScotiScotiaa areaarea.. ThThee LaketowLaketownn dolomitdolomitee (SI(Sl)) anandd oevSevry dolomitdolomitee (Ds)(Ds) strikstrikee nortnorthh anandd araree overturneoverturnedd aatt thithiss localitlocalityy ttoo didipp steeplysteeply ttoo ththee west. . ThThee overlyinoverlyingg quartzitequartzitess anandd shaleshaless (PCu(peu)) araree dip­dip­ pinpingg northwarnorthwardd aatt varyinvaryingg loloww anganglesles . 3366

SoutheSoutherrnn WesWe stt TintiTinticc faufaull tt

A ssuddeuddenn terminatioterminationn 1nin thethe bedbedss ana ndd aann alignmenal i gnmentt ofof

partiapartiallllyy preservepreservedd faultfault facetfacetss 1sis apparenappar entt onon aeriaaeriall photophoto­­

ggraphsraphs,and, and aatt oonnee locatlocatioionn ththee actuaactuall faufaulltt surfacsurfacee 1sis exex-­

pposeo sedd dippindippingg 45 degreedegreess ttoo tthhee southsouth.. ThThee agagee ooff thit hiss faufaultl t -­

inlngg hass not beebeenn deterdeterminedmined.. v

M inorinor ffaulaul tint ingg

SSmalmalll faultsfaults araree seenn ttoo offsetoffset tht hee stratstrataa wherwher ee dis-dis­

tinctivetinctive mmarkearker bedss can bebe fofollowellowedd fof orr ananyy greagr eatt distancedistance..

TheThe AllaAllahh quaquartzitr tzitee especiallespeciallyy showsshows thisthis.. ThiThiss formationformation

outoutcropcropss welwelll,, anandd 1sis offsett bbyy numerounumer ouss faufaultsl ts. . rlthoutWithout doudoubtbt ,, manmany faufaultl tss exexisistt iinn tthhee thicthickk dolomitdol omitee sequencsequencee iinn ththee WesWestt

TlntlcTintic MMinini ningg DistrictDistrict,, asas evidenceevidencedd bbyy ththee mineralizatiomineraliza tionn andand

altalteratioerationn ofof thest hesee rocks.rocks. MinoMinorr faultsfaults oocuroccur over most ofof

ththee area.area. / ThesThesee minominorr faufaultl tss seemm ttoo bbee ofof a shearinshearingg typetype,,

whiwhicch occurreoccurredd atat ththee timetime ooff ththee fofoldinl dingg anandd thrustinthrustingg .. PlaPlattee XX

•

A. ViewView sho~lngshowing quat'tz1tequartzite klippeklippe restingg on. GreaGr8~tt BBluluee limest2.1M8toneone,, ';litwith VeVernornonn CGreel'eek faultfault aatt ththee basbasoe orof thethe auscarpmontenscarpraent .•

,

r

B.. VieVieww showinshowingg verticaverticall ridgridgee forminfor mingg limestonel imestoness ofof LoweLower PennsylvanlaPe nnsylvaniann aga gee offsett bbyy minoln lnorr faultlnfaultingg ~. GEOMORPHOLGEOMORPHOLOGYO GY

ThThee SheeprockSheeprock andand WesWestt TintlcTintic RangeRangess areare maturelmaturelyy erodederoded faulfaultt blocblockk typtypee mountains,mountains, typicaltypical ooff ththee BasiBasinn anandd RanRanggee physiographiphysiographicc province.province.

Faultingg 1sis evidencedevidenced byby ththee lonlongg,, conspicuouslconspicuouslyy straistraighghtt escarpmentescarpment aatt ththee basbasee ooff whicwhichh VernoVernonn CreekCreek flows.flows. TThih iss es­es­ carpmentcarpment 1sis anan obsequenobse.quentt faulf8.ultt linee scarpscarp sincsincee thethe downdown-throw- thrownn sideside formformss thethe escarpment.escarpment. TheThe PaleozoiPaleozoicc outcrooutcropp iinn thethe ex­ex­ tremetreme southersouthernn endend ooff ththee WesWestt TlntlcTintic RangRange 1sis shownshown ttoo bebe abruptlyy terminateterminatedd byby a faultfeult,es, as shownshown byby alialignmengnmentt ooff par­par­ tiallytially preservedpreserved facets.facets.

ManManyy streamm coursecoursess ·areare subsequentsubsequent,, ttoo a greatgreat extentextent governegovernedd byby structure.structure. 6herry6herry CreekCreek ana ndd VernoVernonn CreekCreek flowflow alongg thethe VernonVernon CreekCreek faultfault.. ScotiaScotia GulcGulch andand BateBatess GuGulclchh follofolloww ththee strikestrike ofof PaleozoicPaleozoic formationsformations iinn ththee WesWestt TinticTintic districtdistrict..

DrainagDrainagee patternspatterns areare alsoalso determineddetermined bbyy typetype ofof rockrock beingg dissected.dissected. DendDendritiriticc drainadrainaggee iiss commoncommon inin ththee extru-extru­ sivsivee anandd intrusivintrusivee rocks.rocks. InIn thethe westerwesternn portioportionn ooff ththee area,area, ththee lonlongg,, straightstraight maima inn canyoncanyonss sucsuchh asas ththee GreaGreatt EaEasternstern,,

IndianIndian HoHollolloww andand BucBuckk HoHollow,flollow,floww inin thethe ggeneraenerall didirectior ectionn - ofof thethe didipp ooff ththee PrecambrianPrecambrian formationsformations andand areare thereforetherefore consequentconsequent.. TheTheyy areare joinejoinedd aatt righrightt angleangless byby manmanyy subsequentsubsequent

3737 3388 streamstream coursescourses whicwhichh havhavee cutcut intintoo thethe lessless resistantresistant argilliteargillitess ooff ththee PrecambrianPrecambrian sequencesequence,,forml forminngg a modifiedmodified paralleparallell drainadrainaggee pattern.pattern.

ThThee topographtopographyy 1sis a directdirect resultresult ofof ththee typtypee ooff rockrock exposedexposed ttoo erosionerosion.. IgneousIgneous rockr ockss weatherweather rapidlrapidlyy and,wlthand,with fewfew exceptionsexceptions,, forformm loloww rollingg hillhillss andand broabroadd valleys.valleys.

ThisThis 1sis probablprobablyy duedue ttoo ththee effeceffectt ofof widelwidelyy varyingg tetemperamp era­­ tureturess ooff thisthis desertdesert climateclimate oonn ththee heterogeneouheterogeneouss minermineraall assemblaassemblaggee inin ththee igneousigneous rocksrocks.. LimestonesLimestones areare relativelyrelatively resistant,resistant, andand forformm hihigghh smootsmoothh ridgesridges.. TheThe PrPrecambriaecambriann quartzites,quartzites, althoualthougghh badl badlyy brecciatebrecciatedd byby thrustingthrusting,, havhavee beenbeen thoroughlthoroughlyy recementedrecemented,, andand areare extremelextremelyy resistanresistantt toto erosion.erosion.

TheTheyy forformm ththee highighh ruruggeggedd mountainmountainss ofof ththee reregiongion.. ManManyy greatgreat I blockblockss ofof thithiss quartzitequartzite areare strewnstrewn overover ththee area,area, whichwhich possi-possi­ blblyy represenrepr~sentt residuaresiduall remnantremnantss whicwhichh havhavee reremainem aine~d whilwhilee lessless resistanresistantt rockrockss werweree removedremoved.. (N.(N. C.C. WilliamsWilliams ,, personalpersonal communication.communication.) )

A fefeww evidenceevidencess ofof massmass wastagewastage werweree noted.noted. TheThe larlarggee quartzitquartzitee massmass downdown ththee westwest slopeslope fromfrom MaplMaplee PeaPeakk hahass slumpedslumped downdown frofromm aboveabove,, asas shownshown byby ththee ggullullyy andand hollowhollow aboveabove it.it•

OnOn ththee westwest lilimmbb ooff thethe WesWestt TinticTintic AnticlineAnticline,, a mmuudd flowflow ofof ververyy recenrecentt occurrenceoccurrence wawass oobservedbserved..

ThThee pedimentpediment surfacsurfacee slopingg ggentlentlyy awayaway fromm thethe highhigh mmountainountainss hahass previouslpreviouslyy beenbeen descridescribebedd (p.(p. 2323 ofof thithiss paper).paper). GEOLOGICGEOLOGIC HISTORYHISTORY

General StateStatemenmentt

ThTh~e sequencesequence ofof eventsevents 1nin thethe areaarea isis well defineddefined byby structuralstructural rerelationsl ations;; however,, itit wawass founfoundd necessaryy toto ccorrelatorrelatee witwithh eventeventss ofof adjoininadjoiningg areasareas foforr tentativtentativee datindatingg ooff ththee oroorogenigenicc periods.. ThiThi ss 1sis duduee ttoo thethe factfact thathatt nono sisignificangnificantt amountamount Ooff MesozoiMesozoicc strstratataa isis presenpresentt bbyy whichwhich structural, , sedimentarysedimentary,, oror stratistratigraphigraphicc rerelationshipl ationshipss mighmightt datdatee thethe events.events.

PrecambriaPrecambriann HistoryHistory

VerVeryy littlelittle timetime wawass spenspentt bbyy ththee writewriterr inIn attemptinattemptingg ,i ttoo interpretinterpret PrecambrianPrecambrian historyhistory,, asas iitt woulwouldd addadd littll ittl ee toto ththee purpospurposee ofof thisthis report. . FroterozoiProterozoicc historhist oryy of'of thethe reregiog ionn hahass beebeenn well summarizesummar izedd bbyy EardleEardleyy (1940,, pp.. 840840-841)- 841) •. . IItt 1sis concconcludel udedd thatthat sedimentssediments accumulatedaccumulated 1nin subsidingg troughtroughss toto thicknessesthicknesses ofof mormoree thathann 1212,00, 0000 feet. . ThThee troughtroughss werweree inn parpar tt narronar roww anandd llongong.. OneOne troutrougghh cacallelledd ththee Sheeprock-Cottonv/ooSheeprock- Cottonwoodd apparentapparentll yy exex­­ tendetendedd northeastwarnor theastwardd fromfrom thethe SheeprockSheeprock RangRange ttoo thethe CottonwoodCottonwood uplifupl iftt anandd hencehence eastwareastwardd aalonl ongg thethe sitsitee ofof thethe UintahUintah MountainsMountains.. IItt wawass borderedbordered onon thethe northwestnorthwest bbyy ththee northernnorthern UtahUtah highlanhighlandd andand onon ththee southwessouthwestt andand southsouth bbyy a highlanhighl andd aalonl ongg ththee margimarginn ofof thethe CoColoradl oradoo PlateauPl ateau..

TheThe crystacrystallinllinee highlandhighlandss werweree vigorouslvigorousl yy erodederoded bbyy glaciergl aCier ss anandd runningg waterw~ter.. MMechanicaechanicall weatheweatherinr ingg dominated.. TheThe sedimentsedimentss accumuaccumulatel atedd thickestthickest inin thethe centercenter ss ofof ththee ttroughr oughss andand iinn overlappingg fasfashiohionn onon thethe hihighlandsghlands ..

3939 4400

PaleozoiPaleozoicc HistoryHistory

LoweLowerr PaPaleozoil eozoicc historh istoryy asas indicatei ndicatedd bbyy sedlm~ntssediments presenpresentt 1nin ththee areareaa wawass a timtimee ofof littlelittle tectonitectonicc actiactivityv ity ,, excepexceptt forr ththee gengentltlee subsidencsubsidencee ooff ththee CordilleranCordilleran mmiogeoiogeo­- synclinesyncline.. DepositionDeposition oveoverr mosmoatt ofof earlearl yy PaleozoiPaleozoicc timt i mee concon­­ sistedsisted essentialleS3entiallyy ooff ththee chemicachemicall typtypee withwith approxiapproximatelmatelyy

60060000 feetfeet ofof dolomitedolomitess andand lilimestonemestoness beinbei ngg depositeddeposited,, withwith ononll yy tht hee EurekaEureka quartzitequartzite,, OrienOrientt shalshal ee ana ndd AllaAllahh ququartzitartzitee representinrepresentingg a nearnear shoreshore environment.environment.

Inn UpperUpper MIssissippiaMississippiann timtimee ththee regior egionn becambecamee one ofof slislightlghtl yy lesl esss stablstablee tectonitect onicc environmentenvironment,, witwithh ththee llimestoneimestoness becominbecom i ngg sandysandy,, aanndd witwith tht hee dedepositiopos itionn ooff lilimestoneme s tone,, sshalehaless andd sandstonessandstones continuingg intoInto PennsylvaniaPennsylvaniann time.time.

MMesoo so zoizoicc HistoryHistory

SincSincee ththee only.only*Mesozoi Me sozoicc stratastrata representerepresentedd iiss a mminoinorr outcrooutcropp ooff conglomerateconglomerate,, sedimentarsedimentaryy historhistoryy durinduri ngg thithiss eraera isis obscureo bscure.. IItt 1sis probablprobablyy thathatt MesozoiMe sozoicc sedimentsedimentss wewerree depositedepositedd Iinn tht hee regioregionn whiwhicch werweree latelaterr removeremo vedd bbyy eerosionar osionall forcesforces fofollowinllowingg ththee periodsperiods ofof upliftuplift.. ChChristianseristiansenn (1(1952952 J, p.. 725)725) describedescribess 112,502,5000 feefeett ofof CretaceousCretaceous clasticclastic sedisedimentmentss inin ththee CanyonCanyon RangeRangeJs, anndd iitt sseemeems logicalogicall ttoo assassumumee thathatt dede­­ positiopositionn wawass occurringg atat ththee sitesite ooff ththee presenpresentt WeWesstt TiTintinticc 4411 andand SheeprockSheeprock rangesranges,, possiblpossiblyy onon a similasimilarr scalescale.. AAnn alterna-alterna­ tivtivee interpretationinterpretation cacann bbee mademade,, howeverhowever,, witwithh thithiss regionregion beinbeingg ononee ooff uplifupliftt frofromm whichwhich sedimentssediments werewere derived.derived.

EardleyEardley (1951,(1951, pp.. 274)274) hahass useusedd thethe tertermm CedaCedarr HillsHills orogenorogenyy foforr ththee Mid-CretaceousMid-Cretaceous phasphasee ooff deformatiodeformationn whichwhich immediatelyImmediately precedeprecededd depositiondeposition ofof ththee thicthickk coarscoarsee clasticselastics ofof ththee IndianolaIndianola groupgroup andand KelviKelvinn formationformation ofof centralcentral andand nortnorthh centralcentral UtahUtah.. TheThe uplift,uplift, foldinfoldingg anandd thrustinthrustingg inin thethe

WesWestt TintiTinticc areareaa isis likelylikely parpartt ooff thithiss phasphBsee ofof deformation,deformation, andand occurredoccurred atat ththee samesame timtimee aass ththee CanyonCanyon RangRf.lngee thrust,thrust, althoughalthough ChristianseGhristianse.ln (1952(1952,, pp.. 732732)) assignsassigns anan earlieearlierr LowerLower

CretaceousCretaceous ageage ttoo ththee thrusting.thrusting.

CenozoiCenozoicc HistoryHistory

AAss interpreteinterpretedd fromfrom structuralstructural relationsrelations inin thethe area,area, aa widwidee rangrangee iinn timetime iiss possiblpossiblee forfor ththee emplacemenemplacewentt ooff thethe , intrusions.Intrusions. LoughliLoughlinn (1920(1920,, pp.. 434)454) placeplacedd ththee timtimee ooff thethe monzonitmonzonitee intrusionintrusion inin ththee TertiaryTertiary.. SinceSince ththee intrusivesintrusives cutcut PrecambriaPrecambriann strata,strata, thetheyy areare certainlcertainlyy youngeyoungerr thathann thethe tr...rustingthrusting (Middle(Middle Cretaceous)Cretaceous),, andand thetheyy areare olderolder thathann thethe overlyingoverlying extrusivesextruslves whicwhichh areare EocenEocenee inin age.age. A logicalogicall timetime forfor intrusion,intrusion, thereforetherefore,, woulwouldd bbee during, ththee LaramideLaramide orogeny.orogeny.

IInn thithiss papepaperr a pre-extrusivpre-extl'usivee TertiarTertiaryy ageage wilwilll bbee assignedassigned ttoo ththee intrusions.intrusions• 4422

IInn middlmiddlee ttoo uppeupperr EocenEocenee ththee areareaa wawass coverecoveredd bbyy thickthick flow~l owss ofof rhyolitrhyolitee anandd aandesitendesite.. , BasiBasinn anandd RangRangee faufaultl tss havhavee differentialldifferentiallyy tiltetil tedd andand uplifteupliftedd ththee SheeprockSheeprock anandd WesWe stt TlntlcTintic RangeRengess ttoo producproducee thethe presenpresentt topography._ RejuvenatioRejuvenationn hahass continuecontinuedd intointo fairlyfairly recenrecentt time,, asas shownshown bbyy ththee dissectiodissectionn ooff ththee QQuaternaruaternaryy pedimenpedimentt surfacesurface.. BIBLIOGRAPHBIBLI OGRAPHYY

BauerBauer,, H. LL.. (1952(1952)) FluorspaFluorsparr depositde po sitss aatt ththee NortNo rthh EEnnd ooff SporSporlsfs MountainMountain, , JuaJuabb County,, UtahUtah, , M.SM. S . ThesisThesis, UniversitUniversityy ooff Utah.Utah.

CampbellCampbell , G. S. (1951) Stratigraphy of the House and Confusion Ranges, Millard County, Utah, Guidebook to Geology of Utah, No. 6, pp. 19-25.

Christiansen, , F. W. (1952(1952)) Structurstructuree anandd StratigraphStrati~aph~y ofof thee CanyoCanyon RangeRange,, CentraCentrall Utah^ , G.S.A. . BullBu 1.. Vol01.. 63,63, pppp.. 71717-7407-740..

EardleyEa rdley,, AA.. JJ.. anandd HatchHatch,, RR.. AA.. (1940(1940)) ProterozoiProterozo icc RocksRocks inin Utah,, GG.S.A.• S. A.. Bull.Bull.,, VolVol.. 5151,, pp. 8823-84323- 843..

Eardley,, AA.. J.J. (1(1942942)) Aerial Photographs Photographs:: T'heiTheirr UsUsee andand InterpretationInterpretation,, HarpeHarperr Bros.Bros.,, pp.. 5555-69- 69 .

EEardleyardley,, A. J.J. (1(1951951)) StrStructuraucturall GeologGeologyy ooff NortNorthh America,America, HarpeHarper BBros.r o s.,, pp . 272733 anandd 325325..

GGillulyill ul y,, J.J. (1(1932 932) ) ~GGeolog'iie;;;O~:L:;i0~:;;'.;a:i'y ann:;d~O-"rl1eT.iD:i:e:""d Ore Deposito",s:ni"tiisi-i0rf~T",h'le~S:'it~os of The Stockto",c"k"t",o",nn andand Falr.fleldFairfield Quadranglesus an es,, Utaha,, U.S.G.S..... Profo .. Paper 173, pp. 6-40•. LindLindgrengren,, WW..,, andand LoughlihLoughlih,, G. F. (1(1919919)) GeologGeologyy anandd OOrree DeDepositpositss ofof tthhee TlntTintiicc MininMiningg DistrictDistrict,, UtahUtah,, UU.S.G.S..S.G.S.,, PrProfof.. PaPapeperr 110707 ..

Loughlin,Loughlin, G.. F.F. (1(1920920)) ThThee OOrree DepositDe~ositss ooff UtahUtah,, UU.S.G.S.. S. G.S.,, Prof.Prof. PaperPaper 111,111, pppp.. 423423-439-43 •.

NNolanolan,, T. B. (1(1935935)) TheThe GoGolldd HilHilll MininMiningg District, , UtahUtah,, UU.S.G.S.. S. G. S.,, Prof.Prof. PaperPaper 177,177, pppp.. 112-432- 43 ..

Proctor,Proctor, P.P. D.D. &h otheothersrs,, GenerGeneralizealizedd SectionSection ofof PaleozoicPaleozoic FormationsFormations ExExpose aeedd in the Allen'en ss Rancanch Quadrangleus ran e ,, UtUtahah,, (unpublishedunpublished) ~" " "~"

StStringhamr ingham,, B.. F. ((19421 942)) MineralizatioMi neralizationn inin TheThe WesWestt TinticTintic MMinininingg District,District, GG.S.A.S.A.. BuBull.ll.,, Vol. 53 ,, pppp.. 26267-2907-290 ..

WiWilsonlson,, S. R. (1(1950950)) InInvestigatiovestigationn ofof ththee WestWest TinticTintic TungstenTungsten DDepositeposit , JJuauab CoCountyunty,, UtahUtah,, BuBurr., ofof MMineiness RepoReporrtt ofof InvestfInvestigationgationss 46404640..

4343 Pl at e XI THICK­ ERA PER 100 £Pro FORMATION SECTION NESS DESCRI PTION (FEET) g r: Conql'lmcrate, red, angul ar t o subangular f r agments of PaleozoIc ~ a:: 130 Ii rTl est on e well cem ented in red ca lcereous matrix ~ l>

Z I $ !, Limestone , dar k gray, weath eri no blue-gray ...... ! " ,, ~" '. '.: , - '. , ... .-: : . ~.... '. ' . '. . . /.- z ! - ----== Shale, bl oc k to brown, colcere ous, contains Productid bra chi opods c:{ Oqulrr h =------=: 2 5 0 0 -+ , 0:: ==- - Quartzite, gray, limonite stai .... ing on weathered surface. calc ite ~ , I.J r , i formation (,f) ~ , in fractures, medium gra inp.d, commonly quite porous Z 0 Z -l f ----,-r=.=d._- W 0... ! I r---t-t------~~I ~10"" I Limestone, dark gray,weothering light blue - groi, abundant horn G re at Blue \ \ -1 coral. and cri'noid ste'ms, sandy, cherty z 16. 1 16 « limestone I SO 0 + CL I \ \ a. ond 1 I 1 en undifterenti at- I I I en ~ . ~ ~ ed limestone. I ~ I I ~ 11//11 1---+----4 _?_ ?_ ?_?- ~ / ~ / I / I I I I II I I I I I Dolomite, dark gray, weathering light gray, fine to coorse grained, II/I / I / with Interbedded platy blue-gray limestone I I I r II I I I I I I I I \ I I 7l c .! Allah quar t zi te member, fine to medi um grolned,whlte to li ght gray , Guilmette .~·~ ·it ·~.'~< /(~j .~·.~ \ ~i(' · / I I / / piomlnent be od i ng, som e crossb ed ding formation /Lj /6/ I (61' /6 / /''', Do lomi te , cherty , co ntuins Cladopora sP. / / / / W / / / / -l o / / / -; o / / / / I \6 \ 16 \ 6/ /L::.. / 43 0 Dolomite,dark gray, weathering blue-gray and bl ack, san dy, so me Simonson I I I I / / /' / chert, CIQ do poro sp. ot top of uni t, bl ock l aminat ed beds ch aract - dolomite I . I I rl er istic il l f ormation z I I I I / c:t \ \ I I I I Z- / / / / I 0 / / / / / ! I / Do lomite, medi um gray. weathering Light gray to cream color, > / / / / / w / I I I / 0 ver y fir,,. grained ,conchoi d :.11 fr o ctu r et platy bl eached wni t e U /6/ /.:6./ / - / / I / / locoll y, some thin chert seoms on be ddi ng planes , grades upward 0 I Suy I / / I 700 I I I / I N into overlying lithology dolomite / I / / / 0 I / I / I I w / / / / I I I / .J L:>./ / /A/ I >J / / / ~ / / / / / / / / 7 I Dolomite, medium gray , wEa t heri ng light gray and blue gray, chert y, /6/ /.6/ / 10 fool thick chert bE.'d at bose / / / / 9 4 5 z Lair.etawn 7 I Ii c:t dolomite I I 171 a:: / / / / / :J / / / I .....J 1.6.1 767 / / / / / / /,6/ /6/ Holysites sp. 66.6.6 1------4----1--.? - .? - .? - .? - / / / / J I I I / / / / / I I / / / / Dolomite, dark gray ,weathering b lu e- gray , cherty at bose , block / ~ '/ ' / ! '" / / / / 1.280 ? laminated dolomit e at top, bre ccloted, bleached, with tremol ite nea r Fish Hoven / L:./ / 6/ base dolomite I / / I / / / I /';' . , /~ 1/7 IIII Z I I I I Eureka at~!!~ on weathe red surface, few thin shale partings o 2 00 o Ori ent sha le member I green, to br own, we at heri ng br'l wn , a:: ~Iock.o"ve o I I I I I . den se,metamo rphosed t o hornfels L'>I I \6. \ PogoniP Li.neslonc , cherty, granular bleached and extensively metamorphosed I 1 I I I 1000 formation I \ I T IAI ·ld I I \ I I

. . ;\\:.;:<'-;< : :~.: Quartzite,whlte to gray, brown to buff to PlJrplishbrown on w1!othered --c:.-. -""-::=:: Undlfferent - surface, tint' to medium grained, mass ive, brecci ated and recemented

iattd near thrust plane '. -- :- , .~< ~ ...;. ".. ,~. ':-.., .. «Z 700 0+

ex: Shale, bro wn to green, metamorphosed sl ates and phyll ites I sondy , Z en «- ~ with pebbles to cobbles of well rounded q U ortziTe i n some beds 0:: 5 (J) UJ ex: ~ CL ------' . :" « ex: u UJ W C) 0::: z 0- ::> 0 >

J----l_~L-----1------~- . -- - -. ------1 STRATI GRAPH IC COLUMN OF THE WEST . TI NTIC 01 STRICT AND VICINITY, JUAB CO., UTAH VERTICAL SCALE: I"· '00 FEET