13.19 Uranium Ore Deposits

Tre13.19UraniumOreDepositsKKyser,Queen’sUniversity,Kingston,ON,Canadaã2014ElsevierLtd.Allrightsreserved.13.19.1Introduction48913.19.2TheNeedforUranium49013.19.3GeochemistryofUranium49013.19.4UraniumDepositsThroughTime49213.19.5DepositTypes49313.19.5.1Unconformity-RelatedDeposits49313.19.5.1.1TheAthabascaBasin49413.19.5.1.2TheKombolgieBasin49713.19.5.1.3Karku,Russia49813.19.5.1.4OtishBasin,Quebec49813.19.5.2SandstoneUraniumDeposits49913.19.5.2.1UnitedStates50013.19.5.2.2Africa50113.19.5.2.3Asia50113.19.5.3VeinDeposits50213.19.5.3.1Beaverlodge,Canada50213.19.5.4MetasomaticDeposits50213.19.5.4.1Nametasomatism-relateddepositsofUkraine50313.19.5.4.2Valhalla,Australia50313.19.5.5BrecciaComplexDeposits50313.19.5.6IntrusiveDeposits50413.19.5.6.1Alaskites50413.19.5.6.2Peralkalinesystems50513.19.5.6.3Peraluminousgranites50513.19.5.7Volcanic-AssociatedDeposits50613.19.5.7.1Streltsovkoyecaldera(Transbaikalia,Russia)50613.19.5.7.2Macusani,Peru50713.19.5.8Quartz-PebbleConglomerateDeposits50713.19.5.8.1BlindRiver–ElliotLakedistrict50713.19.5.8.2TheWitwatersrandBasin50813.19.5.9SurficialUraniumDeposits50813.19.5.10CollapseBrecciaPipeDeposits50913.19.5.11PhosphoriteDeposits50913.19.5.12BlackShaleandSeawater51013.19.6Synopsis510Acknowledgments510References51013.19.1IntroductionThediscoveryofuraniumisattributedtoKlaproth,aGermanchemistwho,in1789,precipitatedayellowcompoundbydissolvingpitchblendeinnitricacid,neutralizingitwithso-diumhydroxide,andheatingitwithcharcoaltoobtainablackpowderthatwasuraniumoxide.Henamedthenewlydiscov-eredelementaftertheplanetUranus.In1841,Péligot,aFrenchchemistworkingattheBaccaratcrystalfactoryinLorraine,isolatedthefirstsampleofuraniummetalbyheatinguraniumtetrachloridewithpotassium.Uraniumwasusedduringthenineteenthcenturytocolorpotteryandglassuntilthediscov-eryofradioactivitybyBecquerelin1896(Becquerel,1896),whenheaccidentallyexposedaphotographicplatetoura-nium.AteamledbyEnricoFermiin1934observedthatatiseonGeochemistry2ndEditionhttp://dx.doi.org/10.1016/B978-0-08-095975bombardinguraniumwithneutronsproducestheemissionofbetarays,andthisledtothediscoveryoffissionofuraniumbytheFermigroupon2December1942–theeraofthepoweroftheatombegan.Uraniumisoneofthemostimportantenergy-relatedma-terials,withcurrentusealmostentirelyforgeneratingelectric-ityandasmallproportionforproducingmedicalisotopes.About17%oftheworld’selectricityisgeneratedfromreactorsspreadacross30countries(EIA,2007;OECD/NEA-IAEA,2010),andenergygeneratedfromuraniumhasaminimal‘carbonfootprint’(PacalaandSocolow,2004).AlthoughtheeffectsofthenaturaldisasteratFukushimain2011onnuclearenergyhavecausedmanynationstoreevaluatetheirnuclearenergyprograms,meetingthecurrent,letalonetheprojected,needsoftheuraniumindustryrequiresdiscoveryofnew-7.01122-0489490UraniumOreDepositsdepositsanddevelopmentofnewtechnologiesforbothexplo-rationandprocessing.Thischapterreviewscurrentknowledgeofmajoruraniumdeposits,alongwithsomecriticalgapsintheunderstandingofthemthatalsoexist.Itdescribesthemostsignificantdeposits,discussestheirgenesis,andplacestheminaregionalcontexttoaidfutureexploration.Anadditionalfocusistheuniquenessofuraniumasacommodityandanore-formingelement.Ura-niumasacommoditydiffersfrommostothersinthatmuchofourknowledgehasbeenerodedorhasgoneundergroundsincethelate1970swhentheperceivedneedfornewdepositsdiminished.However,thedemiseoftheformerSovietUnionin1991madenewdataavailable,andtherecentdebateabouturaniumhasstimulatedtheneedtoknowmoreabouthowuraniumbehavesintheenvironment.13.19.2TheNeedforUraniumThecurrentmajoruseofuraniumisforthegenerationofelectricity.The438nuclearpowerreactorsand270researchreactorsrequirenearly60000tU(155millionlbsU3O8)ofuraniumannually(OECD/NEA-IAEA,2008,2010).About25%ofthesereactorsareinNorthAmericaand37%areinEurope.Givenalloftheexistingreactors,the40reactorscur-rentlyunderconstruction,andthoseanticipated,theneedforuraniumisanticipatedtoincreasebyabout30%to82000–100000tU(212–259millionlbsU3O8)bytheyear2025(EIA,2007;OECD/NEA-IAEA,2010).Theuseofuraniumasafuelfornuclearreactorsisnotwithoutitscaveats.Theoperational,maintenance,andfuelcostsfornuclearpowerareonlyhalfofthatforfossilfuels,butnuclearpowerplantscostfourtimesasmuchandrequiremuchlongertimestobuildthanplantsthatusefossilfuels(Ansolabehereetal.,2003).Securinglicensesfornuclearpowerplantsisanarduousandexpensivetask,asisgettingacceptancebythelocalcommunity.Theleadtimeforbuildinganuclearpowerplantislengthy,atleast10years.Theamountofspentfuelproducedeachyearisabout12000t(Vance,2008),butmostofthepotentialenergyinthefuelisnotused.Itcontainsfissionproductssuchasbioactive131I,90Sr,and137Cswithrelativelyshorthalf-livesandmanylonger-China3%Uzbek2%Ukraine2%Niger2%Brazil5%India0.6%Other2%Australia32%Kazakhs17%Russia9%Canada9%(a)S.Africa6%USA4%Namibia5%Figure1Percentageofglobalidentifiedresourcesat<US$130kg
1(a)byclived,intenselyradioactiveisotopessuchas99Tc,140Ce,and239Puthatrenderitdangerous.TheUraniumGroupoftheInternationalAtomicEnergyAgency(IAEA)andOrganizationforEconomicCo-operationandDevelopment(OECD)/NuclearEnergyAgency(NEA)clas-sifiesidentifiedresourcesasthoserecoverablefor<US$130kg
1U(US$50/poundU3O8),whichisneartheaverage‘price’ofuraniumforthepastfewyears.Estimatedglobalresourcesin2009werenear5.4milliontUat<US$130kg
1,withadistinctlackofgeographicdiversitybecause73%oftheseresourcesarelocatedinjustfivecountries(Figure1(a))andthemajororedeposittypesineachisdifferent.Overhalfoftheuraniumresourcesintheworldareassociatedwithsedi-mentarybasins(Figure1(b)).Forexample,in2009,about55%ofuraniumproductionwasfromdepositsinbasins.Butthereisgeographicdisparityinthedistributionofuraniumresourcesrelativetothenationsthatrelyheavilyonnuclearpower.13.19.3GeochemistryofUraniumUraniumisanactinideelementlikethoriumandhasanatomicnumberof92andthreemainnaturallyoccurringiso-topes(234U,235U,and238U),ofwhich238Uisthemostabun-dantat99.3%.LikeTh,itisaradioactiveelement,anditsmoststableisotope,238U,hasaverylonghalf-lifeof4.46109years.Uraniumoccursinnaturalsystemsinthreeoxidationstates,U4þ,U5þ,andU6þ,incontrasttoTh,whichoccursexclusivelyasTh4þ.Inmagmas,thehighlychargedU4þionbehavesincompatibly,becomingconcentratedinlate-stagedifferentiatesandinavarietyofaccessoryminerals.Thus,gran-itesandpegmatitesproducedfromevolvedmagmasarericherinuraniumthanmaficigneousrocks(Table1).Uraniumisgen-erallyhighestinfelsicrocksandinperalkalinerocksovercalc-alkalicandperaluminousequivalents,butsecondarycon-centrationofuraniummayoccurasaresultofhydrothermalactivityassociatedwiththeemplacementofanyfelsicvolcanicandintrusives.Inigneousrocks,uraniumisassociatedwithTh,Zr,Ti,Nb,andrareearthelements(REE),particularlyforperalkalinerocks,butlesssoformetaluminousrocksandnotatallforperaluminousrocks.Metasom11%QPC4%Surficial,brecciaphos14%Unconf13%Sandst25%Brecciacomplex23%Vein2%Intrusive4%Volcanic4%(b)ountryand(b)bydeposittypein2009.DatafromOECD/NEA-IAEA(2010).Table1UraniumconcentrationsingeologicmaterialsReservoirppmAveragecrust1.7Oceaniccrust0.5Uppercontinentalcrust2.7Peridotites0.003–0.05Eclogites0.013–0.8Averagebasalt0.3Mid-oceanridgebasalt(MORB)0.07–0.1Continentalandesites0.5–1.0Islandarcandesites0.2–0.4Averagegranodiorite2.0Averagegranite3.8Nephelinesyenites200–600Alkaligranites20–200Commonshale3.7Blackshale3–1250Sandstones0.45–3.2Averagecarbonaterock2.2Marinephosphates50–300Evaporites0.01–0.43Seawater0.003UraniumOreDeposits491Inotherlithologicenvironments,uraniumismostcloselyassociatedwithredoxactiveelementssuchasMo,V,Se,As,andCu.Levelsofuraniuminsedimentaryrocksarecloselyrelatedtotheirredoxconditions,withthehighestconcentrationsfoundinorganic-richfaciesassociatedwithanoxicenviron-mentsandphosphaticsediments(Table1).Uraniumoccursinrocksasitsownminerals,asasubstituteelementinrock-formingandaccessoryminerals,inexchange-ablepositionsinzeolitesandclays,adsorbedoncrystalfaces,anddissolvedinintergranularfluidsandfluidinclusions.Themineralogyofuraniumiscontrolledbyitshighchargedensity,andthetwoprincipalmineralsareuraninite(writtenasUO2butchemicallyUO2þx;JaneczekandEwing,1992)andcoffinite(USiO4).Pitchblendeisageneraltermgiventothefine-grained,massivecolloformvarietyofuraninite.Additionalcommonmineralsincludebrannerite(U,Ca,Ce)(Ti,Fe)2O6andura-nothorite(Th,U)SiO4.UraniumalsooccursashighlycoloredhexavalentUmineralsasprimaryoreminerals,suchascarnotiteK2(UO2)2(VO4)23H2O,tyuyamuniteCa(UO2)2(VO4)23H2O,orafterthealterationofuraninitesuchasautuniteCa(UO2)2(PO4)210H2OoruranophaneCa(UO2)2SiO3(OH)25H2O(Burns,1999;FinchandMurakami,1999).Inreducingenviron-ments,uraniumoccursasuraninite,coffinite,andphosphates,andinorganiccompounds,asthucholite.Approximately5%ofallknownmineralscontainuraniumasanessentialstructuralconstituent(Burns,1999).Thedegreeofsubstitutionofuraniumintoaccessorymin-eralsiscontrolledbyitseffectiveionicradiusintheoctahedralcoordinationof1.00ÅforU4þ.CompletesubstitutionoccurswithTh4þ,limitedsubstitutionoccursforCa2þinrock-formingmineralsandforZr4þ,Nb5þ,andTa5þinaccessoryminerals,andextensivesubstitutionofuranousionoccursforREEinrareearthfluorocarbonatesandphosphates.Theaqueousgeochemistryofuraniumisunusualinthaturaniumisgenerallymoresolubleinoxidizing,alkalinewaterthaninreducing,acidicwaterdueprimarilytothetendencyofU6þtoformstrongcomplexesinoxidizingfluids,regardlessofthetemperature(Figure2).Uraniumisreadilysolubleinthestronglyacid,oxidizingwateroftenassociatedwithacidminedrainagebecausethehydratedcationUO22þandfluorocom-plexesofuraniumarestablebelowpH4(Figure2).InoxidizedfluidsbetweenpH4and7.5,uranylphosphatecomplexesaretheimportantspeciesandathigherpH,uranylcarbonatecomplexesaredominant.Ingroundwaterwithnormalsulfateconcentrationsof100ppm,uranylsulfatecomplexescanbeasignificantspeciesatpH<7.However,theuranylphosphatecomplexissostablethatforoxidizinggroundwaterswithtypicalconcentrationsof0.1ppmPO4,thiscomplexpredominatesoverallothersfrompH4to10(Figure2).Inreducedground-waters,onlyfluoridecomplexesofU4þaresignificantandonlyatverylowpH(Langmuir,1978).TheextrapolatedsolubilityofUO2inbrinesappearstobeindependentofpHintherange4to10andhasminimaltem-peraturedependencefrom100to300C(ParksandPohl,1988).Uranylcarbonatecomplexesaredominantunderrelativelyoxidizingandnear-neutralpHconditions,andchlorideandsulfatecomplexesaredominantinoxidizingfluidsunderacidicconditionsattemperaturesupto200C.Phosphatecom-plexesremaindominantatneutralpHdespitetheemergenceofimportanthydroxylcomplexesathighpH(Figure2).Evenmoderatetemperaturechangesinthefluidwillnotresultinprecipitationofuraninite,andonlyanincreaseinpHoradecreaseintheactivityofoxygenfacilitatestheprecipita-tionofuraninite(Rombergeretal.,1984).At200Candhighoxygenactivities,hematite,amineralcommonlyassociatedwithhydrothermaluraniumdeposits,wouldalsoform,whereasatlowactivities,pyritewouldbecoevalwithuraninite.Inaddition,U6þreductionbyreactionwithFe2þorreducedcarbonspecies(graphitedoesnotseemtobereactivebelow400Candmustfirstbeconvertedtohydrocarboncom-pounds)isthemostlikelymechanismbywhichuraniniteprecipitatesfromfluids.Experimentsonthesolubilityoflarge,highlychargedionslikeuraniuminsilicatemeltsindicatethatsolubilityincreaseswiththedegreeofdepolymerizationofthemelts(Fargesetal.,1992),whichdependsgrosslyonthemolarexcessofNaþKþCarelativetoAlandthetemperature.Increasingei-theroneresultsinbreakingoftheSi–Altetrahedronchainsinthesilicatemelt,therebyenhancingdepolymerizationandthesolubilityoflarge,highlychargedions.Uraniumsolubilityinmeltsincreasessignificantlywhen(NaþK)/Alratiosincreasefrom0.7(peraluminous)to1.6(peralkaline)(Peiffertetal.,1996).Increasingtheoxygenfugacityorthepresenceofcarbondioxideorchlorineinanaqueousfluidinequilibriumwiththesilicatemelthasaminimaleffectonthesolubilityofuraniuminthemelt.However,fluorinereactswithAltoformAIF63
,therebydepolymerizingthetetrahedralaluminosilicateframe-work(Manning,1981;Schalleretal.,1992)andenhancingtheuraniumsolubilityinthemeltby10–100times.Thesolubilityofuraniuminanaqueousfluidinequilib-riumwithasilicatemeltincreaseswithincreasingoxygenfugacityandchlorideconcentration(Peiffertetal.,1994,1996).Underoxidizingconditions,highsolubilitiesofura-niuminthefluidofupto170ppmresultfromtheformationofU6þchlorideorhydroxyl–chloridecomplexes.Chlorideinthefluidsismuchmoreeffectivethancarbonateorfluoridein020%DissolvedU6+40608010025C100C200C300C2345678910pHUO2HPO40UO2(HPO4)22−UO2(HPO4)22−UO2(HPO4)22−UO2(HPO4)22−UO2SO40UO2ClUO2Cl+UO22−UO22−UO2F3−UO2CO30UO2(CO3)22−UO2(CO3)34−UO2F20UO2F+UO2F42−UO2F20NeutpHNeut.pHNeut.pHNeut.pHCarbonatecomplexesCarbonatecomplexesUO2SO40UO22+UO22+UO2F3−UO2F+UO2F30UO2OH20UO2OH3−UO2OH+UO2OH+UO2Cl−Figure2RelativeconcentrationofuranylcomplexesversuspHat25CforafluidwithSU6þ¼10
8m,SF¼0.3ppm,SCI¼10ppm,SSO4¼100ppm,SPO4¼0.1ppm,SSiO2¼30ppm,andPCO2¼10
2.5atm;at100CforafluidwithSF¼10ppm,NaCl¼1m,SSO4¼1000ppm,SPO4¼0.1ppm,andPCO2¼1atm;at200CforafluidwithSF¼100ppm,NaCl¼1m,SSO4¼1000ppm,SPO4¼1ppm,andPCO2¼1atm;andat300CforafluidwithSF¼10ppm,NaCl¼1m,SSO4¼1000ppm,SPO4¼10ppm,andPCO2¼10atm.ReproducedfromKyserKandCuneyM(2009)Unconformity-relateduraniumdeposits.In:CuneyMandKyserK(eds.)RecentandNot-So-RecentDevelopmentsinUraniumDepositsandImplicationsforExploration,MineralogicalAssociationofCanadaShortCourseSeries,vol.39,pp.161–220.Quebec:MineralogicalAssociationofCanada.492UraniumOreDepositsincreasingthesolubilityofuraniuminthefluid,exceptinreducing,acidicfluidswherefluorideenhancesthesolubilityofuraniuminthefluid.13.19.4UraniumDepositsThroughTimeTheultimateoriginofalluraniumisfromthemantle,butthemostimportantconcentrationsinvolverelativelylow-temperatureprocesses,transportofoxidizeduraniuminfluids,andreductionreactionsorchangesinsolubility.Asaconse-quence,importantdepositsofuraniumdidnotoccuruntiltheoxygencontentoftheatmospherewashighenoughinsurficialfluidstomobilizeuraniumasU6þandthebiospherehadevolvedtobecomeasignificantquantityofreductant.DuringtheArchean,uraniumcouldnotbeconcentratedinsignificantquantitiesuntilelementalcyclingfromtectonicsallowedtheproductionoffractionatedperalkalinemelts(Cuney,2010),whichdidnotoccuruntilafter3200Ma.TheArcheanandearlyPaleoproterozoicsawuraniumdepositedinplacerdeposits,butthesebecomerareinthePaleoproterozoicbecauseofincreasesintheoxygenlevelsintheatmosphereafter2200Ma.ThePaleoproterozoicera(2500–1600Ma)isaperiodofEarthhistorycharacterizedbysubstantialorogensassociatedwiththeassemblageofthemegacontinentsofArctica(Canada,Siberia,andpartsofGreenland)andAtlantica(AfricaandSouthAmerica).GrowthofArcticaoccurredduringthePaleo-proterozoicandthroughthebeginningoftheMesoproterozoicwiththeaccretionofBaltica,NorthAmerica,andEastAntarc-ticaintothelargercontinentofNena(Cawoodetal.,2007;RogersandSantosh,2002;Zhaoetal.,2002).Theseorogensgaverisetoenhanceduraniumconcentrationsinhigh-heat-flowgranites,whoseeventualerosionwouldsupplyU-richmineralstosedimentarybasinsthatwouldforminresponsetodown-warpingduetoplateloadingandrifting.Metamor-phismoflargeareasofthecrustalsooccurred,resultinginsignificanthigh-temperaturesodicfluidsthatcarrieduraniumandproducedmetasomatic-typedeposits(Cuney,2010).TheendofthePaleoproterozoicandbeginningoftheMesoproterozoicismarkedbythegeneralterminationoforogensandaperiodofcontinentalreadjustmentandrelativetectonicquietforabout500My,duringwhichseverallargeintracratonicbasinsformedandevolved.Duringthisperiod,thebasinsandthefluidstheycontainedwouldbeaffectedbyfar-fieldtectoniceventsassociatedwiththereadjustment,whichresultedinchangingthehydraulicgradientswithinthebasinsandcausedbasinalbrinestoflow.AtlanticaandothercontinentalblockswouldbeaccretedtoNenaduringtheGren-villeeventatc.1.0GatoformthesupercontinentRodinia.NeartheterminationoftheProterozoic,theEarthbecomesagitatedonceagainasthemegacontinentRodiniaisUraniumOreDeposits493tectonicallydissectedintoseveralfragments,mainlyalongsu-turezonesformedpreviously(RogersandSantosh,2002).Asaconsequence,manyofthebasinsremainedintactandwouldremainsounlessdeformedbylatertectonicevents.Formationofeconomicuraniumdepositsshiftedtothesubsurfaceofintracratonicandriftbasinsasoxidizedbasinalbrinesmobi-lizedandtransportedU6þthatcouldbeconcentratedbyeffec-tivereductants(Hazenetal.,2008,2009).WhenlandplantsevolvedintheearlyPhanerozoic,theEarthwitnessedforthefirsttimelargedepositsofterrestrialorganicmatteralongwithstabilizedsoilsthatpromotedcohe-siveriverbanksandmeanderingstreamsystems.Asaresult,mudisfoundinmanyPhanerozoicsedimentarysuccessionsdepositedinfluvialenvironments,andtheseservetoconfineaquifersforlaterfocusedfluideventsrelatedtothedepositsthatformedinsandstoneaquifershavingabundantterrestrialorganicmatterortheirdiageneticproducts(Hiattetal.,2007).13.19.5DepositTypesTherearemanydifferentwaysofclassifyinguraniumdepositsdependingonthetendencyoftheclassifiertoputdepositsintomoregenericclassesordividedepositsaccordingtotheirstyleofoccurrence.Noclassificationisperfect,asmanytypesofdepositsfallbetweentheboundariesorarecompositesofdeposittypes.ThemostwidelyusedclassificationbymosturaniumminingcompaniesandresearchersisthatfromtheOECD/IAEA(OECD,2001;OECD/NEA-IAEA,2008,2010),whichdividesdepositsinto15categoriesbasedonthegeologicenvironmentandcharacteroftheuraniummineralizationasshowninFigure3.Oneoftheproblemswithsubdividingdepositsisthatageneticconnotationcanbeimplied,butoneoftheadvantagesisthatthemodelofformationorlocationthatisimpliedcanbeusedtorefineexplorationstrategies.MarineAncientconvergentmarginIntracBlackshalesPhosphatesLignitesMetasomaticdepositsSurficialIOAlbititesSkarnsPegmatitesAnatecticmeltsUncrelaMineralizationPhanerozoicgrProterozoicgraCenozoicsedsFaultsVeinsFigure3SchematicrepresentationofthelocationofvarioustypesofuraniUnconformity-relateduraniumdeposits.In:CuneyMandKyserK(eds.)RecenforExploration,MineralogicalAssociationofCanadaShortCourseSeries,voTwelvedeposittypesaredescribedhere,buttheyencompassnearlyallthosedefinedbytheOECD/IAEA.Gradeandtonnagesindicatethat,exceptforironoxide–copper–gold–ore(IOCG)deposits,namely,OlympicDam,unconformity-relateddepositshavethehighestgradeandtonnage(Figure4).Asagroup,depositsassociatedwithsedimentarybasinsarethemostsignif-icant(Figure1(b)).13.19.5.1Unconformity-RelatedDepositsUnconformity-relateddepositsoccurclosetomajorunconfor-mitiesbetweenArchean–PaleoproterozoicmetasedimentaryrocksandoverlyingPaleo–Mesoproterozoicsandstoneunitsinlargemarginalorintracratonicbasins(Figure5).Thede-positsoccurwithinthebasementorsandstone,butwithinafewhundredmetersoftheunconformity.Thedepositsarehostedbyfaultsandarecommonlyassociatedwithbreccia-tion.TheformationofthesedepositsisrelatedtoareductionfrontneartheunconformitybetweenPaleoproterozoicsand-stonesandunderlyingmetamorphosedbasementlithologies.Theyinvolveformationfrombasinalbrinesat200–250C,sofararerestrictedtotheProterozoic,andformedwithin150Myafterthebasinsformed(KyserandCuney,2009).Unconformity-relateddepositsincludesomeofthelargestandrichesturaniumdeposits(Figure4).Currentmodelsfortheformationofthedepositscanbedividedintotwogeneralend-members.Oneinvolvesthebase-mentasthesourceoftheuraniumandthebasinsasthesourceofthefluids(Cuneyetal.,2003),andtheotherinvolvestheoverlyingbasinasasourceforboththeuraniumandfluid(HoeveandSibbald,1978;Kyseretal.,2000).Thebasementmodelsourcesuraniumfromthebreakdownofmonazitealongfaultzonesasbasinalbrinesinteractwiththebasement.Inthebasinmodel,uraniumisprecipitatedwhentheoxidizedratonicExtensionalbasinConvergentmargindepositsCG/brecciasSandstonedepositsFelsicvolcanicsVeinonformitytedCollapsebrecciapipesCalderaanitoidsPhanerozoicsedimentsProterozoicsedimentarybasinsArchean/Proterozoicbasementschistsandgneissesnitoi