中扬子南缘油苗点油源对比与逆冲推覆作用

江南雪峰山隆起带是在中三叠世末印支运动形成的由东南向北西、由南向北基底拆离的推覆体,它使中扬子区南缘中古生界盆地发生了由强及弱的递进(衰减)变形改造.在江南-雪峰山的推覆体前缘,中扬子区南缘古生界形成了慈利县苗市、赤壁市北门岔、京山雁门口等一系列断展背斜型的油苗.通过油源对比分析表明,这些油苗点接受了来自于围岩和邻近烃源层的混合物,指示了在逆冲断层下盘存在可能被逆掩的烃源区.

The correlation of oil seepages and oil sources and the thrusting nappe structure in the south margin of the middle Yangtze region

The Jiangnan-Xuefengshan mole track is a southeast to northwest and south to north basement detachable nappe.It formed during the Indosinian movement at the end of the Middle Triassic and compelled the Middle Paleozoic basin in south margin of the middle Yangtze region to produce a strong to weak deformation.In the front edge of the Xuefengshan nappe,a series of fault propagation anticlinal oil seepages developed from the Middle Paleozoic basin in the south margin of middle Yangtze region such as Cili Miaoshi,Chibi Beimencha,Jingshan Yanmenkou,and so on.The oil-source correlation indicates that these reservoirs accepted the mixed matters composed of surrounding rocks and hydrocarbon source rocks.This implicates that there may exist hydrocarbon source regions under the footwall of the thrust fault.