The characteristics of Precambrian sedimentary basin and the distribution of deep source rock: A case study of Tarim Basin in Neoproterozoic and source rocks in Early Cambrian, Western China

摘要

Based on outcrops of the whole basin, drilling and seismic data, this paper makes a systematic analysis of Neoproterozoic basin stratigraphic distribution and tectonic evolution characteristics in Tarim. Under the control of the aggregation and breakup of Rodinia supercontinent, the extensional sedimentary basin formed with North-South differences in the Neoproterozoic, separated by the middle ancient land. There is a sedimentary basin in the north, east-west banded, with two thickness centers, Aksu region in northwest and Manjiaer-Kuruketage region in northeast and maximum thickness about 2 500?3 500 m. There are two sedimentary basins in the south, north-east banded, with two thickness centers, Yecheng and Hetian with maximum thickness about 1 500?2 000 m. The evolution of the basin can be divided into two stages, rift in Nanhuan (Cryogenian) and depression in Sinian (Ediacaran), the latter stage deposits larger range but with thinner thickness of strata. Its main rock types contain volcanic rock, clastic rock, moraine rock and carbonate rock. The distribution of source rock during Early Cambrian period is mainly controlled by the development characteristics of the Neoproterozoic sedimentary basin.