SEDIMENTARY FACIES AND PALAEOGEOGRAPHY IN SOUTHERN ANHUI DURING THE LONGTANIAN (LATE PERMIAN)

The early Longtanian(Late Permian)sedimentary strata are obviously governed by bedrock relief in southern Anhui.The sedimentary strata were laid down initially in the to-pographic lows,and then progressively overlapped upon the topographic highs.This dis-trict was an epeiric sea basin during the late Longtanian,and at the latest of the stage,ex-hibited a shallowing trend of sea water.Therefore there are large discrepancies in lithology and lithofacies of the sedimentary strata and ecological environments of the organisms in the study area.The present paper discusses the characteristics of the early Late Permian sedimentary strata and delineates the top and bottom boundaries of the Longtanian strata. Moreover the sedimentary facies and palaeogeographic maps during three substages of the early Longtanian have been compiled in the light of monofactor charts and diagrams in combination with relevant genetic indicators.The results of research in this paper may im-prove our knowledge of understanding in the evolution of the early Late Permian sedimen-tary facies and palaeogeography,and the initiation and development of coal-forming pro-cesses in southern Anhui.