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地球学报 2012
Minerogenetic Series of Ore Deposits in the East Part of the Gangdise Metallogenic Belt
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Abstract:
The Gangdese metallogenic belt is one of the most important continual basements for mineral resources in China.The Lhasa Terrane(Gangdise magmatic arc,III43) is one of the most significant third-level(Ⅲ) metallogenic belts.There is a region from Lhaze County to Gongbo’gyamda County which is 600 km long and 90 km wide and has been studied in detail.There are five ore concentrated areas with the superlarge size Cu polymetallic deposits based on exploration and evaluation:Xiongcun Cu-Au ore concentrated area,Tinggong-Chongjiang Cu polymetallic ore concentrated area,Jiama-Qulong-Bangpu Cu polymetallic ore concentrated area,Mengyaa-Dongzhongla-Yaguila polymetallic ore concentrated area,and Chengba-Nuri W-Mo-Cu ore concentrated area.The research in recent years shows that there are five groups of minerogenetic series composed of Pb-Zn-Ag minerogenetic series group related to Hercynian volcanism and rift valley,Cu-Au-Fe-Pb-Zn-Ag-Mo minerogenetic series group related to Indo-Chinese and Yanshanian sedimentation-tectonic magmatism,Cu-Au-Fe-Pb-Zn-Ag-Mo-W-U-salt deposits minerogenetic series group related to Himalayan tectonic magmatism and sedimentation in the Gangdise metallogenic belt,which are composed of six minerogenetic series and ten subseries of ore deposits.The major subserieses include Cu-Au-Ag-Pb-Zn subseries related to Early Jurassic-Late Jurassic arc-type intermediate-felsic volcanic-supergene rock formation between 173 Ma and 160 Ma in the Yaba Formation in the periphery of Xiongcun and east of Lhasa with a promising potential;Pb-Zn-Ag-Mo-W-Fe subseries(Sharang style,Yaguila style and Dongzhongla style) related to Paleocene-Eocene intermediate-felsic volcanic rock and intermediate-supergene rock formation between 65 Ma and 38 Ma in the Linzhou Basin-Nanmulin Basin and Longger dislocated upwarping belt in the north with a promising potential;Cu-Mo-Pb-Zn-W-Au-Ag subseries(Qulong style,Jiama style,Chongjiang-Tinggong style,Zhunuo style and Bangpu style) related to Miocene intermediate-felsic supergene rock formation between 17 Ma and 13 Ma in the central zone of the east Gangdise metallogenic belt with a promising potential,especially the skarn-type Cu polymetallic deposits in the contact zone of ore-bearing porphyry.The distribution of metals from south to north are Cu-Au(porphyry type)→Mo-W(Cu)(porphyry-skarn type)→Cu-Mo-Pb-Zn(Au-Ag)(porphyry-skarn type)→Mo(Cu)(porphyry type)→Pb-Zn-Mo-W-Fe(porphyry-skarn type) →Pb-Zn(Ag)(hydrothermal vein type).The metallogenic ages from south to north are 173-154 Ma(Xiongcun)→40-20 Ma(Chongmuda etc.)→17-13 Ma(Qulong,Jiama etc.)→65-38 Ma(Sharang,Yaguila etc.).Biotite granite(granite porphyry,quartz porphyry) magmatic activities of Late Yanshanian and Late Himalayanian periods in Gangdise controls the distribution of skarn type Cu-Pb-Zn-Fe-Mo ore deposits.Most skarn type ore deposits occur in the intrusion or the surrounding area within 0-4 km from the intrusion with Cu,Mo,W mineralizations.There are Mo-W-Cu-Zn