The Late Neoproterozoic sedimentary sequences in the Yutang section southwest Tarim Basin and their tectonic implications and hydrocarbon perspective: Insight from basinology

摘要

The Late Neoproterozoic sedimentary sequences in the Tarim Basin are pivotal for understanding basin evolution and related tectonic setting, and evaluating the hydrocarbon perspective. In this study, tectonostratigraphic investigation has been conducted on the Late Neoproterozoic succession in the Yutang area, including strata of the Kexili, Yutang, Kuerkake and Kezisuhumu formations, along the Xinjiang-Tibet Highway similar to 90 km southwest of the Yecheng at the southwest Tarim Basin. The results indicate that the sediments represent a fluvial/alluvial-lacustrine-shallow marine tectonostratigraphic sequence complex upward the section, which is comparable with the deposition of sedimentary basin obeying evolution path from syn-rifting, late-rifting, transitional to post-rifting stage. These results lead to an interpretation of evolution from rift basin to passive margin or cratonic basin for the southwest Tarim Basin during the Late Neoproterozoic. Of these strata, the lacustrine dark shales of the late-rifting stage and the dolomites of the post-rifting stage can server as high-quality source rocks and reservoirs, respectively.