Tectonic Features and Evolution of the Proterozoic Orogenic Belt between Northeastern Jiangxi and Southern Anhui
赣东北-皖南元古代造山带构造格架及演化

The Proterozoic erogenic belt between northeastern Jiangxi and southern Anhui is located in the east part of Jiangnan oro-genic belt on the southern margin of Yangtze plate. The belt has undergone two orogenic stages, namely subduction of early Jingning period and collision of late Jingning period. From north to south it can be divided into Jiuling folded deformation area, Zhanggongshan tectonic melange zone and Jiangshan-Shaoxing end-to-end joint zone. Spaced by regional tectonic zones, these units have been deformed in turn in an increasingly stronger trend. The Middle Proterozoic metamorphic strata belong to Smith Strata, limited Smith Strata and Non-Smith Strata respectively, and hence it is difficult to set up a complete stratigraphic sequence to distinguish them from the traditional "Smith" Strata. Moreover, this set of stratawas formed under the united geotectonic background during the opening and closing of the Yangtze plate and the Cathaysian plate, and therefore some certain connections exist between them. All this distinguishes them from the "geological body tectonics" and "tectonic melange". According to stratigraphic compositionand lithochemistry, a"trench-arc-basin system" model for the dual-arrangedisland arc is established on the basis of the "tectonic melange".