下扬子区中生代前陆盆地

THE MESOZOIC FORELAND BASINS IN THE LOWER YANGTZE AREA

闫吉柱 俞凯 赵曙白 姚柏平 卢华复

YAN Jizhu YU Kai ZHAO Shubai YAO Baiping LU Huafu

中国新星石油公司 华东石油局, 南京 210011 2. 南京大学 地球科学系, 南京 210008

East China Bureau of petroleum Geology, CNSPC, Nanjing 210011, China 2. Department of Earth Science, Nanjing University, Nanjing 210008, China

作者研究了地震剖面、钻井及地表资料后认为,中生代中期(约240～157Ma)下扬子区发育了中部对冲周缘前陆盆地和南部单冲前陆盆地。对冲周缘前陆盆地为约在240～157Ma期间,下扬子板块与华北板块的陆-陆碰撞A型俯冲,下扬子区近同时产生了北部和中南部分别由北西往南东和由南东往北西逆冲的冲断构造而呈对冲结构,并在对冲中心地带沉积了中、上三叠统和中、下侏罗统而成;单冲前陆盆地属于华南前陆盆地的前缘部分,是由于约在240～157Ma期间,华南地区产生了由南东往北西逆冲的推覆构造,在推覆构造前缘沉积了上三叠统和中、下侏罗统而成。其中对冲周缘前陆盆地的对冲中心地带,是寻找海相中、古生界油气藏的最有利地带。

Based on seismic sections,wells and surface surveys,the authors concluded that there exist opposite thrusting peripheral foreland basin in the middle and a single thrusting foreland basin in the south of the Lower Yangtze area in the Middle Mesozoic era(about 240～157Ma).The peripheral foreland basin is the product of A-type subduction resulted from the collision between the Lower Yangtze plate and the North China plate about 240～157Ma.The thrusting structures showed that thrust was from northwest to southeast and from southeast to northwest and the Mid-Upper Triassic and Mid-Lower Jurassic were deposited in the thrusting syncline cores;The south foreland basin is only the front part of South China basins which were resulted from the nappes thrusting from southeast to northwest and the Upper Triassic was depositted in the front of the nappes about 240～157Ma.The thrusting cores of the peripheral foreland basin is the most favourable area for seeking oil and gas traps of marine Meso-Paleozoic group.

https://doi.org/10.11781/sysydz199902095