Tectonic Paleogeographic Pattern And Evolution Of The Eastern Part Of The Jiangnan Orogenic Belt

In the southeast of Yangze block, there are "Pingshui Group" in Pujiang, Mengshan region and Shuangqiaoshan Group in the northeast of Jiangxi province, which are the important part of Jiangnan Orogenic Belt. In order to find out the relationship between these two stratums, including spatial-temporal characteristics and Structural properties, we use tectonic stratigraphy, sedimentology, chronology and rock geochemical methods, study stratigraphic sequence, sedimentary characteristics, detrital zircon age spectrum characteristics, rock geochemical characteristics of the mengshan region "Pingshui Group" and Shuangqiaoshan Group in the northeast of Jiangxi province in depth, and then combine with these characteristics, determine the Prototype basin and tectonic paleogeographic pattern. Based on these works, we have five following understandings:1. Obtain rhyolite zircon U-Pb age in Kaihua, Suzhuang Shuangxiwu Group. The age is777.1±3.6Ma, indicates that there are lots of late neoproterozoic volcanic rock in the northwest of Zhejiang, and the age is the same as Shangshu Group and Jingtan Group.2."Pingshui Group’s" maximum depositional age of about828Ma. Not only should"Pingshui Group"not belong to Shuangxiwu group, but also should not belong to the original definition of Pingshui Group."Pingshui Group" and Shuangqiaoshan Group is the same age’s product, and they are both belong to the the neoproterozoic. Jiangnan orogenic belt was not the same period of Grenville orogenic belt.3. Shuangqiaoshan Group in the northeast of Jiangxi province is flysch deposits, and its paleocurrent direction Pointing to the north, show that the provenance from the south.4. Statistical results of skeleton particles show that the tectonic feature of the provenance of "Pingshui Group" is Magmatic Arc, and maybe different from Shuangxiwu Group’s; the tectonic feature of the provenance of Shuangqiaoshan Group in the northeast of Jiangxi province is Cyclic Orogenic Belt. 5. Through the study of the geochemical characteristics of clastic rock and volcanic rock in Pujiang "Pingshui Group", determine its geotectonic attributes, and reclassify the arc basin structure and the evolution sequencein of the eastern part of the jiangnan orogenic belt.