Filling Sequence and Evolution Model of the Neoproterozoic Rift Basin in Central Yunnan Province, South China: Response to the breakup of Rodinia Supercontinent

Key words: 
• filling sequence /
• basin evolution /
• intracontinental rift basin /
• Neoproterozoic /
• South China /
• Rodinia supercontinent

Abstract: Taking sedimentary filling of the Neoproterozoic rift basin in central Yunnan province as  a research object, sedimentology and basin analysis researches are carried out in this paper. The results show that there are four filling sequences in the Neoproterozoic rift basin in central Yunnan province, representing four basin evolution stages respectively. The Liubatang Formation and lower Luliang Formation, which  were deposited between 820 Ma and 800 Ma   regarded as low density turbidity current   and deep water starved deposits, belonging to the first sequence that represents the rapid subsidence stage of the rift basin;  The Chengjiang Formation, upper Luliang Formation and Niutoushan Formation, which were deposited between 800 Ma and 725 Ma and regarded as fan dalta and lacustrine deposits, belonging to the second sequence that represents the mature development stage of the rift basin;  The Nantuo Formation that might be deposited between 725 Ma and 635 Ma and are interpreted as continental glacial deposits, belonging to the third stage that represents the transition stage from the rift basin to the passive margin basin; The Doushantuo Formation, which were deposited between 635 Ma and 551 Ma and interpreted as tidal flat deposits, belonging to the rift cover. Further study reveals that the Neoproterozoic rift basin in central Yunnan province composed of mini unidirectional half-graben basins during juvenile stage and evolved into a large united half-graben basin during mature stage, which should be attributable to a supradetachment basin. Furthermore, it is demonstrated that the Neoproterozoic rift basin in central Yunnan province should be intracontinental rift basin, which may be related to the breakup of Rodinia Supercontinent.