塔里木盆地南华纪—震旦纪构造-沉积格局

塔里木盆地南华纪—震旦纪构造-沉积格局的深入研究是认识该期盆地构造属性、大陆裂谷形成演化及沉积充填过程的关键。通过对塔里木盆地周缘南华系-震旦系露头、盆地内部钻井及地震资料综合分析，结合前人发表的相关研究成果，对塔里木盆地南华纪—震旦纪构造-沉积格局进行探讨。研究表明，塔里木盆地经历了前南华纪南、北地块的拼合，形成统一的塔里木板块。南华纪—震旦纪，伴随着Rodinia超大陆的解体，塔里木盆地处于拉张构造背景，为大陆裂谷发育时期，并经历了3个演化阶段：①南华纪早期裂陷发育阶段（760~700 Ma），在盆地西部形成阿瓦提裂陷，东部形成满加尔南、北两支裂陷，南部在麦盖提地区形成NW-SE向裂陷；②南华纪晚期—震旦纪早期“裂-拗”体系的转变阶段（660~600 Ma）；③震旦纪晚期拗陷演化阶段（580~540 Ma）。盆地构造格局控制了古地理特征及沉积组合，南华纪以裂陷沉积为主，在强烈拉张作用下形成了碎屑岩-火山岩沉积组合。震旦纪以拗陷沉积为主，塔里木盆地具有“南隆北坳”的古地理特征，发育碎屑岩沉积、碎屑岩-碳酸盐岩混合沉积和碳酸盐岩沉积3种类型沉积组合。

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.