塔里木盆地西南地区前寒武纪基底结构及其演化

Structure and evolution of Precambrian basement in southwestern Tarim Basin

曹自成 蒋华山 张俊程 耿峰 沙旭光 郝建龙 李通 郭小文 陶泽

CAO Zicheng JIANG Huashan ZHANG Juncheng GENG Feng SHA Xuguang HAO Jianlong LI Tong GUO Xiaowen TAO Ze

中国石化 西北油田分公司, 乌鲁木齐 830011 中国地质大学(武汉) 构造与油气资源教育部重点实验室, 武汉 430074 长江大学 油气资源与勘探技术教育部重点实验室, 武汉 430100

Northwest Oilfield Branch Company, SINOPEC, Urumqi, Xinjiang 830011, China Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, China University of Geosciences (Wuhan), Wuhan, Hubei 430074, China Key Laboratory of Exploration Technologies for Oil and Gas Resources, Ministry of Education, Yangtze University, Wuhan, Hubei 430100, China

随着塔里木盆地西南地区深层油气勘探的深入，其前寒武纪基底结构和演化如何影响前寒武纪地层发育及其分布的相关研究具有重要的意义。目前对塔西南前寒武纪基底结构特征缺乏系统全面的认识，制约着该区超深层油气勘探的进一步推进。基于前人的研究成果，采用地质-地球物理综合研究方法，结合前寒武纪基底测年结果，对塔西南地区前寒武纪基底岩性、年龄、结构和演化进行了分析。塔西南前寒武纪基底结构在巴楚隆起区表现为古生界直接上覆在古元古界变质岩/花岗岩之上，在麦盖提斜坡—西南坳陷表现为典型的三层结构，最底部为古元古代变质岩/花岗岩，上覆为南华纪裂陷—震旦纪坳陷演化过程的沉积建造。塔西南前寒武纪基底演化主要经历了5个阶段，即哥伦比亚大陆裂解期(＞1.1 Ga)、塔西南地块与澳大利亚板块聚合期(约1.0 Ga)、南—北塔里木地块聚合期(900~800 Ma)、南华纪裂陷期(760~640 Ma)和震旦纪坳陷期(＜635 Ma)。其中，南华纪裂陷期的隆坳结构控制了震旦系—下寒武统的发育。对塔西南地区前寒武纪基底结构和演化的认识，可为该区深层油气勘探提供重要的理论基础，有助于推动超深层油气勘探的进一步发展。

The intensifying exploration for deep-buried oil and gas reserves in the southwestern Tarim Basin accelerates the necessity to understand how the structure and evolution of the Precambrian basement affect the development and distribution of Precambrian strata. However, the lack of systematic and comprehensive understanding of the structural characteristics of the Precambrian basement in the southwestern Tarim Basin restricts further advancements in the exploration of ultra-deep oil and gas reserves in this area. Based on the previous research results, this study analyzed the lithology, age, structure, and evolution of the Precambrian basement in the southwestern Tarim Basin by utilizing integrated research methods of geology and geophysics and in combination with the U-Pb dating results of the Precambrian basement. The results reveal that the structure of the Precambrian basement in the Bachu uplift region is characterized by Paleozoic strata overlying directly on the Paleo-proterozoic metamorphic rocks/granites. In the Maigaiti slope and southwestern depression, it exhibits a typical three-tier structure: the Paleoproterozoic metamorphic rocks/granites at the bottom, overlain by sedimentary build-ups from the rifting to depression evolution of the Nanhua-Sinian system. Evolution of the Precambrian basement in the southwestern Tarim Basin was primarily transpired in five phases: continental rifting in the Columbia supercontinent (> 1.1 Ga), assembly of the southwestern Tarim block and the Australian plate (about 1.0 Ga), assemblage between the northern and southern Tarim blocks (900-800 Ma), Nanhua rifting period (760-640 Ma), and Sinian depression period (< 635 Ma). The uplift and downwarping structures during the Nanhua rifting period dictated the development of the Sinian-Lower Cambrian sedimentary strata. In-depth research into the structure and evolution of the Precambrian basement in the southwestern Tarim Basin, as presented in this study, provides important theoretical basis for deep oil and gas exploration in the region, and helps to promote further development of ultra-deep oil and gas exploration.

国家自然科学基金联合基金项目 U20B6001

https://doi.org/10.11781/sysydz202305844