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Jeffrey A. Pontius • • • The Cripple Creek volcanic edmplsa was likely formatl by an alternsnnp sebuente of volwNC and dutnma deposrtwn wren conpnued subsidence. The volcanic seduente pnmerdv conaiatad Of mrruawe acuviry Idomaa, tlikef and sdlsl wren ex[ruawe events occurnno as azn has and mmpr flown. mnw diavemu ecnvnv cramd me steep walled, downward hpennp, Cone shaped peometrv. Subaioence reCYUed maenal m a natural mdlmp atppn and In conjunction with ongoing fluidization. Following the active diatramal penoos. some sedimentation occurred wn¢n rediatnbutep matenal m sneer warn antl alluvial•rype features. this type of [vcljC pumping acbon is common in tliatrema tlawbpment and is evident In many parts of the CripDN Creek comDlaa iaee Fpun 61. The IaOat stage of ' igneous aebviry was a aeries of aatellnic domes and flow tlorrtaa Mira - amolaeed around [he main volcanic complex and the errlptepdMR of -~ late ultnmanc dikes. Current litnolopies show only minor evidenn of eatrtaiw maar.: Or tuff nnp type dapOttis. The wssem part of the ditUipt Obathtva s areas of IaNSwn type sedimenu afthouph mev an rtlabeetyehin ano" occur between aanauw piteous taro. Thaw senirtrrtta =a pata110tr- being nnrpnno ee subsidence bean bll. The CriDOM Gaak,oorr(pttfz a has no eManfm not ip[tnp typo features and eMf trietaabrpataev material wnieh suggest limned s1Y1ap wave durirq die 171aYYaa'alda mmwakzkq evems. .T~;`• _., . _'~ Foeowirq the end df wIG1[1C and diatnttlel at:9vilr K GloDla Crank the aru was eapoMO to erdaron antl mina alpifaylaeMbtr Wom regional eroaionat aurtaaa n appun that • tool d abatd.500# feet of erosion Na Olen OIatY aiM 1M and M vol~eiwra_ r"f- . . MINEAALRATION _-'~~~'.'~='? ; -~ The males piteous ano diatferrnl acpvity evflflkl'IM ~Cdgsla+ . Creek t:omPlea may haw 4ated approasmRely 4-5 m.y. baaeaatt4tea r eoverkip DnnriDb reek and altera[IDri types. The main mkteraYOibrt-~ event probably closely followed the diatnmal phase. TM~rttYq~of minMliranon can be bn(iuted betwaerl Ina latest phonbYtieinbbeiYas- Ipoat msm crape diatnma devebpmaMl ano the Mtest-Wpamafie- intrusivo (post mmarau. FDlbwmp the msm rtunerakzkq event, then was a naedvalion cf [M hvdrolhennal svenm whiefl formed sewrM 'hydrotherrnal pipes'. This late event formed tYPtoa1 eoitMtmal vein bract:it type - featlaea. althoupn tnaw features ue minmalizeo, some of the ppld_ appaen to M radutributed hom an artier mmxaliakq event lSelbel. 19911. The ape oaring of this later system is currentW M Prapreas. Golo mmeralizahon within the Cripple Creek oistnet wee prsciplOtad In at least two principle arylea. Tha first is narrow, nipn- prade. Ooltl tellunde-beannp veins with consistent minerNODY antl pntle over ^ wrtlcal extent m axpess of 3000 feat Tha eeeona opl:un as broad zonec of low.pratle. near sunace. disseminated gold which appearf td be most prOOUClive in the upper 1000 flat Of me volcanic complex. Thompson 119851 often a detailed deacnpdon of Me telluride system and tree latest stage epitharmal tlaDOana. fiacent work has Dloupnl to Ilph[ the fipnlficanCe of tree previously untldCUmented tlisseminated, low-prade Oold even[ and how exteneive it is throuphaut the district. Gold IBllurltles primarily occur in narrow veins with a quartz. pyrite. ruble. and fluorlta gangue IThampson. 19841. Thsae high-grape paid telluntla vmn deposits are commonly asaOOOted with me mgor s[fucluhl Mlndf antl Often OGCUr In sheeted atNCNraI adnN a alOpp tree margins of tlikaa. The bulk of the gold mined in the Oistnet came from these nigh-prad0 DOId telluride reins. Lowyraoe. near surface mmml¢auon is commonly miero• crvsnlune native gold and pyrite deposited m oermebWe noat rocks adlicent to malOr atNC[UfBa or withid hwfOlhefinel vent bfecClaf. These low•pratle d6aeminata aepOfns dCCtif ai nanye tWld and pvrKe with K-faltlSpar IpfimarilV i0ulariel OinQue Orpbably fOrnied ae uDpef level ano/or lateral eaorassidn of lha nghgrada awteme lPonbua and ButO. 19911. To tlata tree maldiry of tree Oold Drbduced from Lne tlistnct has been from the polo telluntla phase although. naarh er df Inc new Dulk minable feserves efe flOm th! native QOId'Dyrde Dhafe. This neW W definltl naOVe g01tl•Owde ataOCiahOn naS Mfr1 tM fpNa Of. rlcen[ exPlOOtiOp within me dRtrlpt. RANDOL AT MINEXPO '92 97~ show svmpatnenc low-enple structures or 'flats' occurnn0 between me major mpn-anpa tenures.