江南—雪峰山前缘油气聚集及烃源对比——南方构造问题之三

HYDROCARBON ACCUMULATION AND OIL-SOURCE CORRELATION IN THE FRONT OF JIANGNAN-XUEFENG MOUNTAIN——SERIES 3 OF THE SOUTHERN STRUCTURE STUDIES

  • 摘要: 江南—雪峰隆起带是在中三叠世末印支运动形成的由SE向NW、由S向N基底拆离的推覆体,它使扬子海相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—雪峰推覆体前缘的冲断层—断弯褶皱带(B带),下古生界地层中形成如通山县半坑、凤凰县水打田、阿拉营、慈利县南山坪、麻江等一系列裂隙—背斜型(沥青)古油藏。在逆掩断层—断展褶皱带(C带),上古生界地层中形成赤壁市北门岔、慈利县苗市等断展背斜型油藏及油苗。通过油源对比分析,这些古油藏(沥青)的形成是在印支—早燕山期接受了中扬子早古生代克拉通周边坳陷的盆地中,斜坡相下寒武统、下志留统及下二叠统烃源岩生成的油气,在向台地方向运移时,聚集在推覆体前缘的"X"形裂隙带及断展背斜中成藏。

     

    Abstract: The Jiangnan-Xuefeng uplifted belt is a nappe formed by basement decoupling from southeast to northwest and from south to north at the end of Middle Triassic Indosinian movement.It caused the Middle Palaeozoic marine sedimentary basins to be deformed with the intensity decreasing progressively.A series of palaeo-asphalt oil pool of fracture-anticline type,such as Tongjiang Bankeng,Fenghuang Shuidatian,Alaying,Cili Nanshanping,Majiang,etc.,formed in the overthrust-fault curve folding belt(B zone) in the front of Jiangnan-Xuefeng mountain,in the Lower Palaeozoic.In overthrust fault,i.e.faulted unfurl folding belt(C zone),the oil pools of faulted unfurl anticline type and surface oil formed in the Upper Paleozoic strata in Chibi Beimencha,Cili Miaoshi,etc.Oil-source correlation shows that these palaeo-asphalt oil pools accept the oil from the Lower Camberian,Lower Silurian and Lower Permian slope facies source rock in the Early Palaeozoic cratonic marginal subsidence in Indosinian-Early Yanshan period.They migrate to platform and accumulate in the "X" type fracture belt and compressional anticline in the front of nappe.

     

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