Study On The Late Paleozoic Sedimentary Facies And Sedimentary Environment Of Shanxi Province

Shanxi is the most important coal base of our country, the coal-bearing strata in Shanxi Province has been studied by Geologists of several generations, and a great deal of achievements have been made. The question of this selected works relies on the scientific research project that my tutor undertakes. Based on four field measured sections including Laojingou section in Lingchuan county, Guanjiayu and Dayaotou sections in the east mountain of Taiyuan and Shuiquangou section in Yangquan in Shanxi Province, and materials including 36 collected sections measured by forefathers, the type of the sedimentary rocks, the sedimentary facies and depositional environment has been studied in the paper, and the following understandings can be concluded as follows:1 The main rock type of the Upper Plaleozoic Benxi and Taiyuan Formations have been systematically summarized, and 3 types including clastic rock of terrigenous origin, carbonate rock and coal are recognized. The clastic rock of terrigenous origin includes sandstone, siltstone and mudstone or shale, carbonate rock contains cryptite limestone,7grain (bearing) cryptite limestone,and grainstone or clastic (bearing) limestone.2 The facies of four field measured sections of the Plaoezoic Benxi and Taiyuan Formations of Shanxi have been studied, and three depositional systems and seven types of sedimentary facies have been recognized. The three depositional systems include the bartier island-lagoon-tidal flat, the carbonate platform and the delta systems, in which, the first is made up of the delta plain and the delta front facies, the second is consist of the bartier island, lagoon and taidal flat facies, and the third includes the restricted and open carbonate platform facies.3 Based on the analysis of facies sequence of the section, the sedimentary cycles of these sections have been studied and the horizontal correlations with other sections in Shanxi Province have been made. As a result, nine sedimentary cycles have been divided; the distributional laws of these cycles in the whole Shanxi Province have been analyzed.4 The isopleths plane figures, including sandstone, mudstone, limestone and coal, of the so called Benxi and Taiyuan Formations is made separately. From which, it is demonstrated that the topography of Shanxi Province was higher in the north than in the sounth during the early stage of the late Carboniferous ", but it was reversed after the end of the late Carboniferous. It also demonstrates that the direction of MARINE TRANSGRESSION in north China was first came from the northeast of Shanxi, and then from the southeast.