Nanhua-Sinian tectono-sedimentary framework of Tarim Basin,NW China

The systematic study on the Nanhua-Sinian tectono-sedimentary framework in Tarim Basin is the key to understanding its tectonic attributes,formation and evolution of continental rifts,and sedimentary filling processes.Based on the comprehensive analysis of outcrops in the periphery of Tarim Basin,drilling and seismic data,and previous studies relevant,we discussed the Nanhua-Sinian tectono-sedimentary framework of Tarim Basin.Research shows that there were two individual massifs of the north and south of Tarim in the Pre-Nanhua.The convergence of the north and south massifs led to the final formation of the unified Tarim plate during the Late Pre-Nanhua.During the Nanhua to Sinian,the Tarim Basin was in an extensional tectonic setting as a result of breakup of the Rodinia supercontinent,and underwent the formation and evolution of continental rifts.The evolution of the basin may be divided into three stages: (1) the rifting stage during the Early Nanhua (760-700 Ma), (2) the rifting to depression transitional stage during the Late Nanhua-Early Sinian (660-600 Ma), and (3) the post-rift depression evolution stage during the Late Sinian (580-540 Ma).During the rifting stage,the Awati rift in the west,north and south Manjiar rifts in the east and the NW-and SE-trending rifts in Maigaiti area in the south of the Tarim Basin formed.The tectonic framework of the basin controlled the paleogeographic characteristics and sedimentary assemblages.In the Nanhua,rifting predominated,resulting in clastic-volcanic rock assemblage under intensive extension.In the Sinian,depression predominated in Tarim Basin which showed the paleogeographic characteristics of uplift in the south and depression in the north,resulting in three types of sedimentary assem-blages,i.e.clastic rock,mixed clastic-carbonate,and carbonate assemblages. © 2018, OIL & GAS GEOLOGY Editorial Board. All right reserved.