Late Proterozoic Colisional Orogen and Geosuture in Southeastern China:Petrological Evidence

The Jiangshan-Shaoxing fracture belt(JSFB)is a Late Proterozoic geosuture due to islandarc-continent collision in South China.The Cathaysian Block(CT),lying on the southeast side ofJSFB,is composed of green schist-amphibolite complexes in the form of a series of tectonic flakes.On the northwest side of JSFB,which is located in the border area of Zhejiang,Jiangxi and Anhhiprovinces(abbreviated as ZJP-JXP-AHP),are distributed an ophiolite suite and other rocks,constituting the Jiangnan ancient island arc(JN)on the southeast margin of the Yangtze Block(YZ).The collision between JN and CT at～0.9Ga ago led to the folding of JN,followed by theintrusion(～0.9-0.8Ga ago)of many dioritic and ultramafic stitching plutons along the fracturebelt.As a result,the basic Precambrian tectonic framework of southeastern China was shaped.