THE CHARACTERISTICS OF CARBONIFEROUS SEDIMENTARY FACIES AND PALEOGEOGRAPHY IN SOUTHERN ANHUI

Carboniferous sediments in southern Anhui were mainly deposited in continental-marine transitional and marine environments. The sediments in the tran sitional environment are mainly represented by near-sea lacustrine facies and littoral paludal facies. The sediments in the marine environment can be divided into tidal flat, lagoonal, inshore platform, infralittoral platform and beach facies, and in addition, sedimentary facies composed of a mixture of clastic rocks and carbonate rocks is also well developed. According to the characteristics and associations of sedimentary facies, sedimentary models for Carboniferous carbonate facies and mixed facies dominated by terrigenous clastic rocks in southern Auhui have been constructed respectively. From an analysis of the paleogeography and paleostructure in the early and late Yangttan stage, early and late Datang stage, early and late Weining stage and Maping stage in the Carboniferous, the authors have further ascertained the early Carboniferous paleogeograpical framework of "three uplifts and two depressions", i. e. a framework of alternate arrangement of the Chaohu depression, Xuanjing depression, Zhangbaling oldland, Tongling peninsula and Jiangnan oldland. On that basis the Conditions and basis for the existence of the above-mentioned oldlands in the Early Carboniferous have been determined. The features of changes of Carboniferous paleogeography and paleoclimates are also dealt with in the paper.