NEOPROTEROZOIC RIFTING HISTORY OF SOUTH CHINA SIGNIFICANCE TO RODINIA BREAKUP

The Neoproterozoic basins in South China are characteristic of rift basins, and their evolutions are closely related to the breakup of Rodinia. 1. The basins evolution underwent four major development stages. (1)fluvial littoral to deeper water deposition stage; (2)continental to marine volcanic dominated stage, (3)continental ice cap to continental glacial shelf sea dominated stage, (4) carbonate and/or carbonaceous siliceous sediments formed stage. 2.The age determination by sensitive high resolution ion microprobe(SHRIMP) indicates that the evolution of rift basin experienced four stages:(1)the formation of the rift basement; (2)the formation of mantle plume and graben basin; (3)the subsidence of the basement and filling of the rift body, and (4)passive subsidence and formation of the rift cover. 3. The study of South China rift suggests that: (1) the rifting operated during the late Neoproterozoic was worldwide, which brought about a number of rift basins around individual continents after the breakup of Rodinia. This rifting event was responsible for the separation of Australia from Yangtze(600 Ma~550 Ma), and of Laurentia from Cathaysia. (2) The South China block lay between eastern Gondwanaland, Laurentia and Siberia.