Sedimentary Response Of Emeishan Mantle Plume In Eastern Yunnan

The Emeishan Basalt is the only Large Igneous Provinces that approved by the thehe international academic community,as might lead to the Permian changes in global climate and environment and bio-mass extinction event, it gets the estensive attention by scholars at home and abroad。Over the years,many geologists have done a lot of study work at some different fields, regional structural geology, rock geochemistry, magma dynamics included.But,all the Previous work has focused on large regional scale,without any analysis and investigation to the local area, and faults activities.In this paper, a combination of sedimentary and tectonic research method is used,with stratigraphic correlation, paleontological contrast, conglomerate origin and provenance analysis,a lot of work was done to the Ganluo-Xiaojiang fault,Puxiong-Pudu River fault,and the fracture areas, also the plume tectonics and sedimentary response in this area are discussed, and obtained some preliminary understandings that followed:1. According to the stratigraphic correlation,we found that the Qixia and Maokou stratigraphic thickness on both sides of Ganluo-Xiaojiang fault and Xichang-Qiaojia fault are different to the other, the east side is much thicker. And, the Qixia Formation thickness difference is small, the differences in Maokou significantly increases. Combined with fusulinid fossils identification,it was the normal faulting of Ganluo-Xiaojiang fault and Xichang-Qiaojia fault from the end of the Liangshan period,that got the synsedimentary phenomenon. Only in the upper Maokou exist denudation differences.2. The fusulinid fossils of Daqiao section are completely identificated,according to the fossil contrast,the Qixia and Maokou formation are divided,the thickness of Qixia formation is 59.5m,and the thickness of Maokou formation is23.7m.In the sample of the top of the section,two fusulinid fossils were found that belong to the Yabeina-Neomisellina zone. The existence of these two fossils descripts that this section reserves a larger part of Maokou formation,only the top part that develops Yabeina-Neomisellina zone was eroded.This also be verified in the Baiguowanzi section in Huili, some fusulinid fossils belong to the Yabeina-Neomisellina zone were also found.3. According to the stratigraphy, paleontology contrast and conglomerate analysis, four nearly EW sections of this region arrange from the time before magmatic activity to the end of the Permian. These profiles descript that due to plume activity,three important faults were activated,and normal faulting occurred one after another,and controlled the distribution of the related stratum.