A Study On The Sedimentary Character And Paleogeography Of The Mesoproterozoic Jixianian Period In Western Henan Province

The Mesoproterozoic Jixianian is widely distributed and its complete section was developed in western Henan Province, one of the best areas in the North China Platform where the stratum of the Mesoproterozoic Jixianian is distributed.Based on all kinds of qualitative and quantitative data of the features and associations of sedimentary rocks and sedimentary structures of 129 outcrops, the maps of single factors and sedimentary facies of the Early, Middle and Late Jixianian of Mesoproterozoic in western Henan Province have been compiled, using the single factor analysis and multifactor comprehensive mapping method proposed by professor Feng Zengzhao. Futhermore, the tectonic– paleogeographic characteristic of Mesoproterozoic Jixianian in western Henan Province was discussed.The research of sedimentary and palaeogeographic which Combining quantitative and qualitative has the important guiding sense to the deposition minerals forecast and the exploration.In the Early Jixianian, western Henan Province was characterized by the deposition of beach facie and neritic facies, and in Lushi—Luanchuan areas barrier beach facies was dominant.The facies of the Middle Jixianian came into those of the Early Jixianian, but the Lushi—Luanchuan area was characterized by a restricted carbonate platform. The pattern of facies of the Late Jixianian in study area had changed. Songshan—Jishan area of the Early,and Middle Jixianian changed from an old land to a branching bay. Queshan area in south received deposition of barrier beach facies. There was no significant change in Lushi—Luanchuan area where restricted carbonate platform was developed. In other areas, beach facies and neritic facies were deposited.In brief, The transgression continued from the Early Jixianian to the Late Jixianian, the source area of substance was the north China continent of north and east, the paleocurrent direction was from north to south, the material was from the North China Platform, the tectonic setting of the area was the passive continental margin, and the tectonic-paleogeographic characteristic was that the aulacogen was the subsidence and basin fill stage.