Palaeogeographic characteristics of the Middle Permian Shanxi Age in Henan Province
Hu Bin1,2, Zhang Lu1, Liu Shunxi1, Song Huibo1, Shi Lailiang3, Hu Lei1
1 Institute of Resource and Environment，Henan Polytechnic University，Jiaozuo 454003，Henan 2 Key Laboratory of Biogenic Traces & Sedimentary Minerals of Henan Province，Jiaozuo 454003，Henan 3 School of Resource and Earth Science，China University of Mining and Technology，Xuzhou 221116，Jiangsu
Abstract：The Middle Permian Shanxi Formation of Henan Province developed a set of deposits of littoral facies and delta facies characterized by the clastic coal measures，which is the important coal-bearing strata during the Late Paleozoic in Henan Province.Based on the isoline trend analysis of thickness of the formation and the sand-mud ratio，as well as distribution features of facies fossils and sedimentary assemblage types，four sedimentary facies including lagoon（bay） facies,tidal-flat facies,barrier island facies and delta facies can be distinguished and three types of lithofacies areas can be divided，including the delta sandstone and mudstone lithofacies，bay（lagoon）-tidal flat siltstone and mudstone lithofacies，and barrier island-tidal flat-lagoon（bay）sandstone and mudstone lithofacies.The Middle Permian palaeotopography of Henan Province displays a higher terrain in the north and west，and a lower terrain in the south and east，and there exists a palaeo-uplift area under water in central section，therefore， the regression occurred from northwest to southeast within this province；Old land are situated along the Funiu Mountain in southwestern Henan and Zhongtiao Mountain in western Henan，thereout，there are two sedimentary areas of the largest thickness of this formation that lie in the northeastern and eastern of Henan Province.It is possible to infer that provenance is from the western old land（Zhongtiao Mountain） which is shown evidently in the lithofacies palaeogeographic map.
