广西百色地区中上二叠统沉积体系研究

RESEARCH ON DEPOSITIONAL SYSTEM OF MIDDLE AND UPPER PERMIAN IN BAISE AREA, GUANGXI ZHUANG AUTONOMOUS REGION

以沉积学为研究手段,通过对大量的地表露头剖面的宏观岩石学特征、沉积构造的详细研究,结合室内薄片的微观岩石学特征,揭示出广西百色地区中上二叠统主要由台间盆地、开阔台地、台地边缘等三种沉积体系构成。其中台间盆地主要分布在右江断裂以南、德保—田东以西的地区;开阔碳酸盐台地主要分布在盆地北部的巴马和盆地东部及南部的大片区域。台地前缘斜坡、台地边缘浅滩和点礁等台缘相区主要分布在右江断裂沿线和田东县的作登圩、江州等地。由东向西,由开阔碳酸盐台地→台缘沉积体系→台间盆地沉积体系的演化次序反应了沉积环境由浅变深的过程。最后,从生、储、盖相互匹配的角度,提出了百色地区古生界油气藏可能发育在被上覆中新生代厚层碎屑岩所覆盖的古生界台缘相碳酸盐沉积区。

Taking sedimentology as the study means, through overall study on surface macroscopic outcropping characteristic and sedimentary structure, including micropetrological structure character of laboratorial slice, it is pointed out that the Middle and Upper Permian consists of carbonate platform, platform margin, and basins among platforms in Baise area. Basins among platforms lie to the south of Youjiang fault and the west of Debao & Tiandong country; the open platform lies in the Bama country and the eastern & southern Baise Basin; the platform frontier slope, marginal platform shoal and patch reef are distributed along Youjiang Fault and Zuodengxu, Jiangzhou of eastern Tiandong County. From eastern to western, the evolutional sequence, from open carbonate platform to platform margin and then to basins among platforms, which reflects the shallow-to-deep process of sedimentary environment. From the standpoint of 'source-reservoir-caprock' assemblages, it was suggested that the Paleozoic oil and gas pools in Baise area may be preserved in carbonate rock area of the Paleozoic marginal platform facies, which were covered with Meso-cenozoic clastic.