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Jeffrey A. Pontius <br />II <br />m <br />Q <br />L. <br />V <br />C <br />O <br />~, <br />r <br />U <br />• • • f~~T~T4idlD <br />• <br />:aa <br />Ii~Dlmp l <br />r <br />a~ fa a <br />~O <br /> <br /> <br />VY~ ` <br />r 9 <br />~8f ~e <br />I~YIt9 <br />a <br />t+ ~ <br />37 41 45 a9 53 57 61 65 <br />ULTR/1a/L51C as al1SIC 521HTERNmL4TE 63 <br />i i <br />maQM9Um minerals. The late hVtlrOtn Omal icbvrtV ha3 tOrmeo a <br />variety Or self ates alOnp WRh iUCh mmllalf as Plpfite, lpDVtlrlte. Opal <br />antl chalceoonv. <br />GeOChlmiCally, the Cripple Creek svs[!m if ennchetl m Au. Ap, <br />Te. As. ea. La ano Mn witn weakly anomalous Ph. Hp, Sb. V. Whole <br />rOCk tlara for me OiSInCL SNOWS a typllal paOChlmlCil flpnafpre Similar <br />to other alkaline system! wnhm the Rocky Mouniam region. The <br />notapls ekcepuon a me oust lamoroonvre mtruswe avem most main <br />ore pePP$IIIPOI. `.YhOle rOCk tla[i from me Cres50p irea for [hR <br />inlrusrve event DIOt3 as an ultramahc lamoroonvre. <br />LAMPROPHYRE ASSOCIATION <br />Several of the Dikes in the central Donlon of the Cresson <br />Oeposn nave a abca content below 35%. In atltlition. analyses of rare <br />eanhf snow a strong lnrichmint in bOih heavy ano light elements rn <br />These same low sikca tlikes. Whole rock oaW snows elevate0 levels of <br />Cu. Cr antl W for me same Dikes. Birmingham 119901 oescnbei tnese <br />undersaturated lamoropnvras as moncnipuites. <br />Spatially, monchipmte dikes occur near [he center of the <br />C re SfOp Ore ppdV. CpmPpfltlpnallY ano tektpallV Ili! tlikes ar! Slmdar <br />m Omer Idmpropb Vres in the ogIrICI. These mOOChipune oiklS Hive <br />very low gold values ICOmmonly 10 to a0 ppbl antl era preflrantrally <br />not minerahteo even wnhm the or! bOtlv. Or! pgtle mmeOIIL[IOn <br />doe3 OcCUr sloop me iamprpphYre marpin3 and lnt0 tits nP3t fOCk Dut <br />(l.es f3as and others 1986) <br />>~lD <br />69 73 77 <br />nclo s~21e"x FIG.7 <br />rarely mvatles the tlike itself. Thess ulvamahc rocks are mrtrrrorav <br />weakly carOOnata and sentlie alteraA. <br />It is Dalievetl loaf Mesa ultramafic, high rata earth lamprophvraf <br />reorasen[ Primitive magmas whrOn ascanoetl raoitlly from the rrlartM. <br />Thin feCllOn oats fhOwf a varlery of matK phenOtrvtts IampllDOlaa. <br />bioti[e. pvrokenes ano olivine) a1 a floe preload matna of K•faMapar. <br />Ieb50a[Oitl3 antl plapOCliSe. WherOS mOa[IamprOPhYreamlM dlalftC[ <br />Ivopesrtel show tlifferlntuuon antl evWubpn lormmp a praoabpntl <br />saOVence f0 phOnOlltic rocks. these primitive ullramafiC tllket at <br />Cresson are a separate ano OlStinPL pOpUlailOn antl may Oa aaaoeuuo <br />with tleao structural tonouns {3!e !loins 71. <br />ORE CONTROL <br />The brimarv ore control for poitl mineralizanan In Ina CrippM <br />Creek tli5[nCt is N! pre-mmetll SIn1CNfa1 labnL. This tibflC. lief Iwo <br />Oominant trentls. NNW ano NE. which correspontls to tits raptptal <br />structural pa[tern in me Preombnan rocks. Most of loess malOr <br />structural :ones are steeply dipornp won poop Vertical conwum of <br />mmenlisanon. the bulk mmaDle, bvwryraos tlaposns founo to data <br />are pnmanly conunep to slruetwal mtenecuon point! or aldlp Na <br />malPr north Lfentlinp soli! aOnef. These bwefgratle dePOadf OOWr <br />in all rOCk rypef bUi ire best Oevabpatl e1 Ine oNtlamal Draftta antl <br />PraPamDrtart adrift anO Qrwas YMtf. <br />1 <br />1 <br />i 100 RANDOL AT MINEXPO '92 <br />PLOT OF CRIPPLE CREEK DISTRICT LAMPROPHYRES (Mefic Rocks) <br />ON A TAS (Total Alkali-silica) CLASSIFICATION CHART <br />O" _ <br />N <br />Y_ <br />t _ <br />O. <br />N <br />e3 <br />Z _ <br /> <br /> <br />