南黄海盆地是下扬子地块向海洋的延伸,中三叠世以前为统一的海相盆地。目前陆上地区下三叠统沉积相展布已经基本搞清,但是海区研究程度较低。结合陆上下扬子地块的研究成果,通过实际的钻井、地震资料分析,开展了南黄海盆地南部坳陷下三叠统沉积相研究,结果表明:研究区下三叠统沉积体系呈NE向展布,由NW向SE水深逐渐变浅,依次发育台缘斜坡相、开阔台地相和局限台地相;局限台地相暗色泥岩和泥质灰岩发育,为有利的烃源岩。
The South Yellow Sea Basin,as the extension of the Lower Yangtze Block to the sea,is a unified marine basin before Middle Triassic.The distribution pattern of the Triassic sedimentary facies is basically figured out on land,but the marine area remains to be researched.Referring to the researches onland,this paper is devoted to the Lower Triassic sedimentary facies of the Southern Depression of the South Yellow Sea Basin by analysis of drilling and seismic data.The results suggest that the Triassic sedimentary systems are distributed in the north-east direction of the study area where the water depth becomes shallower from northwest to southeast.Facies of platform margin slope,open platform and restricted platform successively occur along this direction.Among these facies,the dark mudstone and shaly limestone deposited in the restricted platform are the favorable source rocks.The results are meaningful to oil and gas exploration in the Triassic.