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塔西南坳陷南华纪—震旦纪裂谷分布与烃源岩发育关系密切。综合西昆仑露头资料、钻井信息和地震剖面信息,分析了南华纪—震旦纪裂谷形成的大地构造背景和展布特征,探讨了裂谷发育与下寒武统烃源岩分布的关系。研究认为,塔西南坳陷发育南华纪—震旦纪裂谷,处于塔里木地块南缘,形成于Rodinia超大陆裂解初期,由昆仑山前的莎车、叶城和皮山地区延伸至麦盖提斜坡,呈NE向展布,边界为正断层控制,南华系—震旦系发育断陷转向坳陷、陆相转向海相的构造沉积组合。南华纪—震旦纪裂谷发育控制着上覆寒武系底部烃源岩分布,寒武系烃源岩的沉积与震旦纪末古地貌关系密切。钻井证实有上震旦统白云岩沉积的区域往往有玉尔吐斯组发育,上震旦统白云岩地震反射特征为连续层状中强振幅,地震剖面上较好识别,有助于间接反映玉尔吐斯组烃源岩分布范围。塔西南坳陷寒武系玉尔吐斯组烃源岩主要分布在昆仑山前带和坳陷中部裂谷发育区内。
The distribution of the Nanhua-Sinian rift in the southwestern Tarim Basin is closely related to the source rock development. Based on the information of western Kunlun outcrop, drilling information and seismic profile, the tectonic setting and distribution characteristics of the Nanhua-Sinian rift are analyzed. The relationship between the development of rift and the distribution of the Lower Cambrian source rocks is discussed. The study shows that the South China-Sinian rift developed in the southwestern Tarim basin is located in the southern margin of the Tarim block and formed at the initial stage of the Rodinia supercontinent. It extends from the Shache, Yecheng and Pishan areas in front of the Kunlun Mountains to Maigai The slopes are distributed in a NE direction with normal faults controlled by the boundary, the tectonic sedimentary assemblage of the South China-Sinian faulted-down depression and the continental facies turning to the marine facies. The Sinian-Sinian rift controlled the distribution of the source rocks at the bottom of the overlying Cambrian. The Cambrian source rocks are closely related to the paleomagnetic anomaly at the end of Sinian. Drilling confirmed that most of the Upper Sinian dolomite sediments are developed in the Yü Tu Tuo Formation and that the seismic reflection characteristics of the Upper Sinian dolomite are continuously laminar and medium-strong amplitudes that are better identified on seismic sections and contribute indirectly to the reflection Yurtuite Formation source rock distribution range. The source rocks of the Cambrian Yurbuosi Formation in the southwestern Tarim Basin are mainly distributed in the Kunlun foreland belt and the central rift development zone of the depression.