On the Cenozoic tectonics and basin dynamics of the South China Sea
Zhang Gongcheng1 Wang Liangshu2 Tang Xianchun2,3 Zhang Kaijun2 Liu Shaowen4 Zhao Zhigang1 Wang Peng1 Zhong Kai1
1.CNOOC Institute, Beijing 100027;2.School of Earth Science and Engineering, Nanjing University, Nanjing 210093;3.Guangzzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640;4.Key Laboratory of Coast and Island Development, MOE,Nanjing University, Nanjing 210093
The South China Sea is located at the conjunction of the Eurasia，IndiaAustralia and Philippine plates，and is the largest marginal sea in the western Pacific area.The mechanism and tectonic evolution of the South China Sea，which will shed great insights into the interaction between the Tethyan and Pacific tectonic realms and the assessment of the oil and gas potential，are still open to intense debate.Based on the existing srtructural and tectonic information of the South China Sea and its adjacent areas，we tentatively dicussed the tectonic evolution of regions around the South China Sea during the Early and Late Tertiary through the Quaternary.The origin and evolution of the South China Sea were largely restrained by the IndiaAsian collision and the rotation of continental blocks along the Red River fault during the Cenozoic. South China Sea developed under the riftstrike tectonic background with the levorotaroty of Red River fault transfer to dextrorotation accompanying the convergency of IndiaAsian plate.Cenozoic subduction of the Pacific plate beneath to the Erasian continent result the disintegration of accumulated East Asian terranes during the Mesozoic.Continous continental subduction of South China Sea casused the underplate of basalt and uplifted the continental curst，and initite the broad magmatisms during the MidMiocene，and formed the miniature of modern South China Seas deformation and tectonic framework.Generally，the South China Sea experienced initial marginal rifting in early and Middle of the Early Tertiary，strikeslipping pullapart and oceanic extension during the later Early Tertiary to the early Late Tertiary，and Neotectonism from later Late Titary to Quaternary，respectively.Meanwhile，sedimentary sequences correspongding to the relevant tectonic setting.Cenozoic basins within the South China Sea have undergone different formation times，continental marginal deformation and basin characteristics because of the multiple plate tectonic dynamics around it.The northern South China Sea is a typical extensional continental margin result from the extension of oceanic crust，while its southeast is a compressional margin and its west is a transfer extensional continental margin.