Sedimentary Facies And Deposition Enviroment Analysis Of South Tianshan Aierbin Paleozoic Basin In Xinjiang

Aierbin Paleozoic Basin which lies at north edge of Tarim plate is an important part of Tarim plate. It is located in the east of Hula Mountain late Paleozoic taphrogenic trough,southeast of East Alai-Haerke Paleozoic complex trench-arc belt.Its north boundary is the seam of Tarim plate and Junggar plate, and is adjacent to Kuruktag epicontinental block in the south.Because Aierbin Paleozoic Basin is adjacent to the seam of two plates in the north,there is much significance in the research of sedimentary facies and depositional environment.Through the integration of actual wild work , data collection,indoor study and understanding of predecessors, we get some understanding an follows:According to ancient environment and tectonic movement, Aierbin Paleozoic Basinis production of two phases in one deposition period. The first period sedimentary productions are Kerkeztam Formation in Lower Silurian, Arbeshimaiblarke Formation in Lower Devonian,Arlatager Formation and Sarming Formation in Middle Devonian,Hazerblake Formation in Upper Devonian. It is a large set of sedimentary rocks of shallowshelf facies and biohermal facies in shallow water environment. The second sedimentary productions are Gancaohu Formation in Lower Carboniferous. It is still a set of sedimentary rocks of shallow water facies.But it is unconformity with first period for mations because of the variation of tectonic environment.From tectonic environment in late Paleozoic in this area, South Tianshan ocean basin got in the stage of continual expansion from Silurian to late Devonian. The sedimentary environment was stable correspondingly,And the contact relations of the formations are conformities. Ocean basin began to shrink from late Carboniferous and part of strata were denuded because of rising up,which lead to unconformity of Gancaohu Formation in Lower Carboniferous and Hazerblake Formation in Upper Devonian.From the attribute of basin, Aierbin Paleozoic Basin belongs to continent margin sedimentary basin which formed by plate dispersing:Tarim plate Rodinia supercontinentbegan to depart from Sinian Period.After collision and splicing between micro-plates in early Paleozoic, South Tianshan ocean basin began to closure stage from many basins stage and formed Aierbin Paleozoic Basin in the end.From the evolution of Tarim basin, we can see that:the large set of sedimentary rocks in north edge of Tarim plate is a set of passive continent margin sedimentary rocks with great thickness of shallow shelf facies and biohermal facies sedimentary rocks in shallow water environment. So the strata in Aierbin Paleozoic Basin are formed by passive continent margin sedimentation, Aierbin Paleozoic Basin is also passive continent margin sedimentary basin.