The Metallogenetic Mechanism Of The Huize Lead-Zinc Ore Deposit And The Occurrence Of Germanium, Yunnan Province, China

Kuangshanchang and Qilinchang in Huize, Yunnan province, are the large Pb-Zn depositswith extremely enriched Ga, In, Ge and Cd in the carbonate rocks of the lower CarboniferousBaizuo Formation (C₁b) occurring near the Emeishan basalt. Based on the previews researchresults, the author has further done research on the characteristics of geology, petrology,mineralogy, geochemistry and geochronology in the Huize Pb-Zn ore deposit, concluded anddiscussed the metallogenetic mechanism, and also established a preliminary metallogenetic model.The main ideas that the author has are following:.1. Mineralization in Kuangshanchang and Qilinchang Pb-Zn deposits was supposed to bemainly controlled by the tectonic activities, and the fratures were the main structure aspassage-way for ore-forming fluid. Orebody mostly occurred in the fractures among carbonaterocks strata of the lower Carboniferous Baizuo Formation (C₁b); hostrocks of the orebody includethree assemblages: limestone-limestone; dolostone-dolostone; limestone-dolostone.2. Shale in the strata of the lower Carboniferous Baizuo Formation (C₁b) formed the clayminerals in the orebody after the ore-forming fluid alteration.3. The ore-forming fluid with highly concentrated metals, pulsated into the interlayerfractures and formed the extremely rich Pb-Zn orebody.4. The conetent of Fe in sphalerite was banded following the pulsation of the ore-formingfluid, and this caused the phenomena of color bands in sphalerite.5. The characteristics of the trace elements and rare earth elements suggested that theore-forming elements had the same source and this source might relate to the Emeishan basalt. Thevalue of S isotopes in galena, pyrite and sphalerite showed that the source of S was crust; inaccordance with the similar value of C and O isotopes in calcite and the wall rocks, it suggestedthat the wall rocks might be the source of C and O. The characteristics of platinum group elementsshowed that partial ore-forming elements were from the mantle-related Emeishan basalt.6. The isotopic age by Sm-Nd dating of calcite was 220±14Ma, which was close to theepisode of the Emeishan basalt activity.7. Ge occurred in sphalerite as Zn's isomorph.The metallogenetic process that the author proposed was: in the late Permian Period, theactivities of Emei mantle plume changed the tectonic pattern of this region and the mining district,and caused the tensional tectonic environment there; before the effusion of the Emeishan basalt,the Emeishan basaltic magma heated this region, drove the migration of the gas and liquid,impelled a large amount of ore-forming fluid to move and made some ore-elements dissolve in theore-forming fluid; ore-forming fluid followed the fratures and metals deposited in the layeredfractures among the carbonate rocks under the fit conditions. Following the pulsation of Emeishanbasalt, the ore-forming fluid pulsated into the interlayer fractures among the carbonate rocks and formed the pretty rich Pb-Zn ore; Ge entered the ore-forming fluid and then went into sphaleriteoccurring in sphalerite as Zn's isomorph.. Tectonic activities after Permian Period, such asIndosinian and Himalayan orogeny, formed the regional thrust nappe structure and changed thespacial shape of the orebody.