贵州水城矿区上二叠统层序地层及控煤作用

Sequence Strata and Coal Control of Upper Permian in Shuicheng Mining Area,Guizhou

贵州西部水城矿区主要的含煤地层晚二叠世龙潭组为典型的海陆过渡相含煤岩系,其沉积环境有下三角洲平原、潮坪和泻湖等。作者对水城矿区上二叠统含煤岩系龙潭组和汪家寨组层序地层进行了分析,共识别出4个层序界面,并根据层序界面将水城矿区上二叠统划分为3个层序地层,层序Ⅰ从峨眉山玄武岩顶界到标七底界;层序Ⅱ从标七底界开始到四号煤层底板;层序Ⅲ从四号煤层底板开始到二叠系与三叠系的不整合面。三个层序地层中层序Ⅱ煤层发育最好,层序Ⅲ次之,层序Ⅰ最差。在层序中又进一步划分出低位体系域、海侵体系域和高位体系域,其中尤以海侵体系域最有利成煤作用,高位体系域次之,低位体系域最差。

The coal-bearing Longtan formation in Shuicheng mining area is a typical transitional facies coal -bearing rock series, there were delta plain, wad and lagoon under this sedimentary environment. In this paper, the coal-bearing Longtan formation and Wangjiazhai formation of upper Permian are studied, 4 sequence boundaries are identified, Permian of Shuicheng mining area are divided into 4 sequence strata, sequence I is from basalt top boundary of Emei mountain to mark 7 bottom boundary, sequence II is from mark 7 bottom boundary to, sequence III is from No. 4 coal floor to unconformity interface of Permian and Triassic, coal in se- quence II developed the best, then sequence III, sequence I is the worst. The sequence are divided into lowstand system tract, transgressive systems tract and highstand system tract, notably the transgressive system tract, the most favourable coal highstand system tract times, lowstand system tract is the worst.