Geological Features Of The Waxi Formation,Fanjingshan Group,East Guizhou,China And Their Tectono-Paleogeographic Implications

The Fanjingshan Group, outcropped in the northeastern part of Guizhou province,is over 10,000 m thick succession of strongly-deformed,low-grade metamorphic volcanic rocks and terrigenous clastic rock, overlaid Angular unconformably by the Xiajiang Group. This paper uses tectonic stratigraphy and sedimentary geology theory,method, studied the stratigraphic sequence, sedimentary geology characteristics of fanjingshan group, And on the basis of comprehensive analysis of the predecessors’ research results, discusses the prototype basin and tectonic paleogeographic pattern of waxi 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,which belongs to Neo-Proterozoic.The main body for thick metamorphic sandstone in light grey, metamorphic siltstone,sandstone sericite SLATE, silty SLATE. Oblique bedding, parallel bedding development in sandstone; Powder sandstone, SLATE, silty SLATE have horizontal bedding, parallel bedding. In the metamorphic- fine sand structure, metamorphic silt structure, etc.2. Through surveying small oblique bedding in Medium and coarse grained turbidite sandstone of 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, sediment diffusion direction from south to north, show that provenance located in the south area of the Fanjing.3. The skeleton sandstone particles statistical results show that the fanjing mountains group of sandstone provenance tectonic attribute is magmatic arc.4. Comprehensive above research results, combined with contemporary four fort group of tectonic environment, speculate fanjing mountains of clastic rock series tectonic environment shall be the back-arc basin(epicontinental sea).5. The jiangnan orogenic belt western general type is in the western Pacific active continental margin, the development of the western margin of theneoproterozoic magmatic arc volcanic series constituted at the time, the development in the south of clastic rock series is back-arc extension and edge into the sea. Such as Xia Jiang group and Fanjingshan group.