贵州西部晚二叠世晚期煤系沉积相和沉积体系

SEDIMENTARY FACIES AND DEPOSITIONAL SYSTEMS OF LATE LATE PERMIAN COAL MEASURES IN WESTERN GUIZHOU

一、概述贵州西部是华南晚二叠世主要聚煤区之一。上二叠统煤系厚100至500余米,沉积类型多样,以细碎屑岩和泥岩为主,东部夹碳酸盐岩。各地含煤10—80层。晚二叠世时,研究区西边有康滇古陆,东部过渡为碳酸盐台地(图1)。

The sedimentary facies of the late Late Permian coal measures in western Guizhou were once interpreted by the previous workers as delta facies or tidal-flat facies, both of which graded westwards into fluvial facies, and eastwards into a carbonate platform. Unlike previous studies, the author contends in this paper that the above-mentioned two sedimentary facies occurred simultaneously in western Guizhou at least during the late Late Permian. They may be ascribed to the delta system and barrier-lagoon system, respectively. The coexistence of the two depositional systems in places is interpreted by the author as the delta-barrier complex which is similar, to a certain extent, to that of the Upper Cretaceous coal measures in Utah and to that of the Carboniferous coal measures in eastern America. The late Late Permian coal measures in the study area are believed to be composed of delta system, barrier-lagoon system and their complexes.