TECTONIC EVOLUTION AND ITS CONTROL OVER HYDROCARBON IN SOUTHERN CHINA
ZHAO Zong ju 1, YU Guang 1, ZHU Yan 2, ZHOU Jin gao 1, TU Xiao long 1(1. Hangzhou Institute of Petroleum Geology, CNPC, China; 2. Geoscience Department, Zhejiang University, China)
The tectonic evolution of southern China after Sinian was mainly related with the drifting and rift colliding history between Yangtze plate, Cathaysian plate, North China plate, Kula Pacific plate, India plate, Indosinian massif, Northern Viet Nam massif, Songpan massif, Yidun massif, Changdu Simao massif, Baoshan massif, Tengchong massif and Hainan massif, etc. According to the thoughts of plate tectonics and mobilism, the authors divide the tectonic evolution history of southern China as 2 stages, that is, the marine basin stage (Sinian to Middle Triassic) and continental basin stage (Upper Triassic to Quaternary), and further divide it into 12 sub stages, that is, the Yangtze craton peripheral rift basin(Sinian to Lower Cambrian Qiongzhushi Stage), rift craton passive continental margin basin (Lower Cambrian Changlangpu Stage to Lower Ordovician), passive continental margin craton foreland basin(early Upper Ordovician to Silurian), Caledonian movement(the end of Silurian), rift craton basin(Devonian to Lower Triassic), craton residual marine basin back arc turbidite basin(Middle Triassic), Indosinian movement (Middle Triassic to Upper Triassic), collision between North China plate and South China plate, close of paleo Tethys and formation of foreland basins (Upper Triassic to Middle Jurassic), transformation formation of pull apart basins under background of compress shearing (Upper Jurassic to Lower Cretaceous), formation of continental rift basins (Upper Cretaceous to Paleogene), Himalayan movement (at the end of Paleogene to early Neogene) and formation of draping synthem(Neogene to Quaternary ). Especially, the paper makes a systematical research on the tectonic evolution after middle late Triassic and its controlling over the existent hydrocarbon in southern China, and puts forward the new viewpoints that the Yanshanian movement of late Jurassic to early Cretaceous controlled the preservation or destruction of the Mesozoic Paleozoic primary reservoirs and the Yanshanian and Himalayan movements controlled the distribution of the existent primary, secondary and hydrocarbon regeneration (the second hydrocarbon generation) reservoirs in southern China. The tectonic evolution before the Yanshanian stage controlled the formation and distribution of the Mesozoic Paleozoic primary reservoirs in southern China, which are chiefly distributed around paleo uplift and the intensity of Yanshanian movement in late Jurassic to early Cretaceous controlled the preservation or destruction of these primary reservoirs. In Sichuan basin, the primary reservoirs have preserved, but in other areas of southern China, they are mostly destroyed. The tectonic evolution of Himalayan finally controlled the genetic types and distribution of existent commercial reservoirs. The primary Tertiary reservoirs are distributed in Tertiary rift basins, such as northern Jiangsu, Jianghan, Baise basins etc., the secondary Mesozoic Paleozoic reservoirs are chiefly distributed over western areas of southern China, such as Sichuan, Cuxiong basin, and the hydrocarbon regeneration Mesozoic Paleozoic reservoirs are mainly distributed in Tertiary rift basins in the middle lower Yangtze area.