Sedimentary Geological Features Of The Upper Terrigenous Clastic Series Of The Fanjingshan Group,South China And Their Tectonio-paleogeographic Framowork

The Fanjingshan Group,outcropped in the northeastern part of Guizhou province,Stratigraphic distribution centered on Fanjing Mountains,a succession of strongly-deformed,low-grade metamorphic volcanic rocks and terrigenous clastic rock,overlaid angular unconformably by the Xiajiang Group.Tectonic location for the northwest end of the Jiangnan orogenic belt,This paper uses tectonic stratigraphy and sedimentary geology theory,method,studied the stratigraphic sequence,sedimentary geology characteristics of Fanjingshan Group,find out the Fanjing Mountains special group of copper factory set of stratigraphic sequence,the stratigraphic composition,formation environment,the research on basic geologic issues of basin filling sequences.Analysis to determine the Huixiangping Formation of basalt tectonic attribute,and on the basis of comprehensive analysis of the predecessors' research results,discusses the prototype basin and tectonic paleogeographic pattern of Tongchang Formation in Fanjingshan Group.The following main progress:1.A new sense of stratigraphic sequence of Fanjingshan Group in western guizhou neoproterozoic of Jiangnan orogenic belt,The main body for thick metamorphic sandstone in grey,metamorphic siltstone,sandstone sericite phyllite,slate.Central with discontinuous multilayer metamorphic volcanic rock,basalt,spilite.2.Through surveying small oblique bedding in medium and coarse grained turbidite sandstone of Tongchang formation and Waxi Formation,and according to the level of correction and the rose diagram,shows some informations about upper turbidite clastic rock series of Fanjingshan Group in the northeastern part of Guizhou province.Paleocurrent overall points north and northeast,sediment diffusion direction from south to north,They continuously provide detrital material to the north.3.The skeleton sandstone particles statistical results of thick sandstone of Tongchang Formation and Waxi Formation show that the Fanjingshan Group of sandstone provenance tectonic attribute is magmatic arc.4.We collected pillow basalts of Huixiangping Formation in the wild,the samples of typical pillow structure.By analysis of samples of whole rock geochemical results features indicate that the formation of the tectonic environment for active continental margin,formed in the back-arc extension.5.Comprehensive research results,According to the diagrams of tectonic settings for basalt samples of Shaojiwa Formation and Xingzi Complex Group in Lushan and basalt samples of Fanjingshan Group,speculate the tectonic environment of clastic rock series of the Fanjingshan Group shall be the back-arc basin(epicontinental sea).Combining previous research results,we know Fanjingshan Group and Sibao Group which exposed in north Guangxi province constitute d one complete arc-basin system.the Jiangnan orogenic belt is a typical subduction orogenic belt in the western Pacific Ocean or a typical active continental margin in the western Pacific active continental margin.In the period of the upper clastic sedimentary of Fanjingshan Group.