中国中西部晚古生代—中三叠世沉积盆地原型

中国中西部晚古生代—中三叠世沉积盆地的形成演化受控于4大重要地质事件:一是从晚泥盆世到早石炭世古亚洲陆块的形成,由于古亚洲洋壳的俯冲消减,西伯利亚陆块与古中国陆块由天山—阴山造山系缝合成巨型古亚洲陆块;二是石炭纪—早二叠世巨型古亚洲陆块受地幔柱的作用,发育天山大火成岩省与多条裂谷;三是早石炭世一直延续到中三叠世古特提斯洋扩张和古亚洲陆块南东南边缘离散;四是晚二叠世—中三叠世峨眉地幔柱与多条裂谷。晚古生代—中三叠世,中国中西部地区存在4类盆地原型:(1)离散板块边缘盆地,形成于古特提斯洋拉张期,主要分布于华南陆块北西缘、南缘以及塔里木陆块的南缘;(2)会聚板块边缘盆地,于晚二叠世—三叠纪形成于华南陆块南缘、中晚泥盆世—石炭纪形成于华北陆块北缘以及泥盆纪—石炭纪发育于中央造山系的一侧或两侧;(3)克拉通内盆地,包括台内坳陷和台内断陷及残余海盆;(4)裂谷和拗拉槽,即与天山大火成岩省和峨眉地幔柱相关的裂谷和拗拉槽。

Prototypes of sedimentary basins in central and western China from Late Paleozoic to Middle Triassic

The formation and evolution of sedimentary basins were controlled by 4 important geologic events in central and western China from the Late Paleozoic to the Middle Triassic.1)From the Late Devonian to the Early Carboniferous,the Pal-Asia Ocean subducted.The giant Pal-Asian Landmass came into being when the Siberian Landmass had been connected with the Pal-China Landmass through the Tianshan-Yinshan Orogenic Belt.2)From Carboniferous to the Early Permian,influenced by mantle plumes,Tianshan(central Asia) large igneous rock province and several rift valleys generated in the giant Pal-Asian Landmass.3) From the Early Carboniferous to the Late Permian and the Middle Triassic,the Paleotethys Ocean expanded and the SES margin of the Pal-Asian Landmass detached.4) From the Late Permian to the Middle Triassic,the Emei Mantle Plume and several rift valleys generated.4 basin prototypes existed in central and western China from the Late Paleozoic to the Middle Triassic.1)Basins in the detaching margins of plates.They generated when the Paleotethys Ocean was expanding and mainly located in the northwestern and southern margins of South China Landmass as well as the southern margin of the Tarim Landmass.2)Basins in the convergent margins of plates.From the Late Permian to Triassic,they generated in the southern margin of the the South China Landmass.From the Middle and Late Devonian to Carboniferous,they developed in the northern margin of the North China Landmass.From Devonian to Carboniferous,they developed in one or both sides of the Central Orogenic Belt.3)Intracratonic basins,including intra-platform depressions,inter-platform faults and remaining marine basins.4)Rift valleys and aulacogens related to the Tianshan large igneous rock province and the Emei Mantle Plume.