Evolution and mineralization of the Late Paleozoic basin in the West Kunlun,China
In the northern part of the West Kunlun,due to the convergence of the Paleo-Tethys,back-arc extensional tectonic belts and a series of Late Paleozoic sedimentary basins were formed.The following issues have been emphatically reviewed in this paper.1)The Tamu-Kalangu basin belt,in which the Middle Devonian-Late Permian strata were deposited continuously due to the depression,on the southern margin of the Tarim Block is tectonically equivalent to the far-field continental back-arc environmental basin.The Oytag-Kuerliang basin belt,in which the Middle Devonian-Late Permian strata were deposited intermittently due to the rifting,on the northern margin of the West Kunlun Block,is tectonically equivalent to the back-arc basin.Although these two basins are separated by the Tiekelike uplift,they have simultaneous evolutionary processes.2)There are two stages of magmatic rocks in the basin.The first one is the bimodal igneous rocks which coincide with the basin expansion period(339-291 Ma),and the second is the intermediate-acidic magmatic rocks(265-206 Ma)related to the basin closure.3)In the basin evolution process,syngenetic sedimentary deposits,mainly including marine sandstone copper deposits,sedimentary manganese deposits,and VMS type copper deposits,were formed in closed basins locally in the depression under anoxic environment condition during the period of basin expansion from the Middle Devonian to the Early Permian.During the basin closing period from Middle Permian to Early Triassic,the basin-mountain transition resulted in the folding of sedimentary basement,magmatic activities,and tectono-hydrothermal and mgmatic-hydrothermal metallogenesis.In conclusion,the Late Paleozoic extensional tectonic environment of the region was controlled by the Paleo-Tethys convergence.Sedimentary deposits,magmatic-hydrothermal deposits as well as tectono-hydrothermal deposits were formed in these basins in the basinal expansion-closing evolution process.
Late Paleozoic basinback-arc environmentlead-zinc-copper-manganese depositWest Kunlun
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