应用露头层序研究合山煤田合山组煤层的成因

THE ORIGIN OF COAL IN HESHAN FORMATION STUDIED BY OUTCROP SEQUENCE METHOD IN HESHAN COALFIELD

合山煤田煤层的成因问题一直存有争议。通过露头层序地层分析将该区煤层分为两种类型，一种产在台地低水位楔状体内，另一种产在海进体系域中。前者厚度大，结构较简单，煤质较好，为近海湖泊淤浅成煤；后者厚度小，结构复杂，煤质差，为滨海潮上带成煤。其独特的碳酸盐岩型含煤是由于缺乏陆源碎屑供应等所致。

The origin of coal beds in the Upper Permian Heshan Formation in the Heshan coalfield has been disputed for long time.The authors divide the coals in the Heshan coalfield into two types based on the outcrop sequences study in the study area.One type is developed in lowwater wedges formed in a carbonate platform.This type of coal has a larger thickness,simpler structure and higher quality,and was formed in the swamps resulted from the fillingup of paralic lakes,Another type of coal is developed in transgressive depositional system tracts.This type of coal is small in thickness,complex in structure and poor in quality,and was accumulated in littoral supertidal environment.The unique carbonate rock type coal measures in the Heshan coalfield was caused by the specific paleogeological setting in which the terrigenous supply is lack.