Shangzhuang gold deposit located in the Wangershan fault zone of northwestern Jiaodong is of meso- hypogenic altered rock type. The ore bodies occur at the hanging wall and footwall of Wangershan fault in vein or irre...Shangzhuang gold deposit located in the Wangershan fault zone of northwestern Jiaodong is of meso- hypogenic altered rock type. The ore bodies occur at the hanging wall and footwall of Wangershan fault in vein or irregular shapes with the NE strike, NW trend, 30° -60°~ in dip and the lateral trending of SW. The ores are composed of pyrite, quartz, sericite, bismuthinite, native gold, bismuth sulfosah minerals, chalcopyrite, etc. , shown as brecciated structure and vein structure with metasomatic dissolution textures. The wall rock altera- tion is mainly described as phyllic alteration and silicification. The mineralization of this deposit is controlled by structure and altered rocks. The ore-controlling fault structures of this deposit is Wangershan fault, of which the intersection of major fault and secondary fault is the main ore-bearing position of this gold deposit, and the lar- ger arc curved position is a favorable part for ore body occurrence. On the plane, the ore body is shown as equi- distant pinch-out reproduction.展开更多
The Yidun Island Arc in the Three Rivers (Jinsha River, Lancang River, Nujiang River) region of southwestern China is one of the most important Kuroko-type volcanogenic massive sulfide deposits (VMS) in China. Intra-a...The Yidun Island Arc in the Three Rivers (Jinsha River, Lancang River, Nujiang River) region of southwestern China is one of the most important Kuroko-type volcanogenic massive sulfide deposits (VMS) in China. Intra-arc rifting of Yidun Island occurred during the Late Carnian-Norian when VMS deposits such as the Gacun Pb-Zn-Cu deposit were formed. A bivalve fauna was found in fine-grained tuffaceous slate and in mineralized tuffaceous siltstone containing very high contents of Pb (45.01-103.37 ppm) and Zn (135.78-300.03 ppm) of the upper Tumugou Formation in the Changtai-Gacun volcanic-sedimentary rift basin. Stratigraphically, the bivalve-bearing beds are equivalents of the Gacun Pb-Zn-Cu deposits. The diversity of this bivalve fauna is very low. It consists mainly of the thin-shelled, epibyssate suspension-feeding bivalves Pergamidia eumenea and Parapergamidia changtaiensis, the burrowing large, elongated, suspension-feeding Trigonodus keuperinus and Unionites? sp., and occasional specimens of the endobyssate suspension-feeding Trigonodus? sp. and the deep burrowing suspension-feeding Pleuromya markiamensis. Individuals of the first four taxa are so abundant that the specimens are sometimes concentrated in shell beds, probably indicating a gregarious habit. This bivalve fauna is associated with internal moulds of cylindrical, slightly conical tubes most likely produced by a worm-shaped organism. Composition, morphology, diversity, and high abundance of this fauna, chemical features of the surrounding sediment, and the tectonic setting all suggest that this bivalve fauna lived in a deep-water environment in or around a hydrothermal vent system.展开更多
文摘Shangzhuang gold deposit located in the Wangershan fault zone of northwestern Jiaodong is of meso- hypogenic altered rock type. The ore bodies occur at the hanging wall and footwall of Wangershan fault in vein or irregular shapes with the NE strike, NW trend, 30° -60°~ in dip and the lateral trending of SW. The ores are composed of pyrite, quartz, sericite, bismuthinite, native gold, bismuth sulfosah minerals, chalcopyrite, etc. , shown as brecciated structure and vein structure with metasomatic dissolution textures. The wall rock altera- tion is mainly described as phyllic alteration and silicification. The mineralization of this deposit is controlled by structure and altered rocks. The ore-controlling fault structures of this deposit is Wangershan fault, of which the intersection of major fault and secondary fault is the main ore-bearing position of this gold deposit, and the lar- ger arc curved position is a favorable part for ore body occurrence. On the plane, the ore body is shown as equi- distant pinch-out reproduction.
基金supported by National Science Foundation of China (Grant Nos. 40372014, 40172011, 40472013, 40743016 and 41173058)the fund of Cross Century Talent of Ministry of Education of China, the Distinguished Young Scholar grant of Sichuan Province and China Scholarship Council
文摘The Yidun Island Arc in the Three Rivers (Jinsha River, Lancang River, Nujiang River) region of southwestern China is one of the most important Kuroko-type volcanogenic massive sulfide deposits (VMS) in China. Intra-arc rifting of Yidun Island occurred during the Late Carnian-Norian when VMS deposits such as the Gacun Pb-Zn-Cu deposit were formed. A bivalve fauna was found in fine-grained tuffaceous slate and in mineralized tuffaceous siltstone containing very high contents of Pb (45.01-103.37 ppm) and Zn (135.78-300.03 ppm) of the upper Tumugou Formation in the Changtai-Gacun volcanic-sedimentary rift basin. Stratigraphically, the bivalve-bearing beds are equivalents of the Gacun Pb-Zn-Cu deposits. The diversity of this bivalve fauna is very low. It consists mainly of the thin-shelled, epibyssate suspension-feeding bivalves Pergamidia eumenea and Parapergamidia changtaiensis, the burrowing large, elongated, suspension-feeding Trigonodus keuperinus and Unionites? sp., and occasional specimens of the endobyssate suspension-feeding Trigonodus? sp. and the deep burrowing suspension-feeding Pleuromya markiamensis. Individuals of the first four taxa are so abundant that the specimens are sometimes concentrated in shell beds, probably indicating a gregarious habit. This bivalve fauna is associated with internal moulds of cylindrical, slightly conical tubes most likely produced by a worm-shaped organism. Composition, morphology, diversity, and high abundance of this fauna, chemical features of the surrounding sediment, and the tectonic setting all suggest that this bivalve fauna lived in a deep-water environment in or around a hydrothermal vent system.
