The stratigraphic age and detrital provenance evolution of the Donghetang Formation in the western Tarim Basin

The Tarim Basin, situated as a significant oil and gas exploration and development research region within China, has undergone a multifaceted tectonic evolution over time. Nonetheless, the existing studies have not adequately acknowledged the potential reservoirs within the Silurian-Devonian system in the central and western sectors of the basin. In this research paper, our focus is on core samples extracted from the Donghetang Formation, obtained from Batan 6 well, Kangtan 1 well and Yu 2 well. Our objective is to identify the depositional characteristics, material source evolution and age attribution of the Donghetang Formation. This analysis combines various factors, including the clastic fractions of sandstones, heavy minerals, zircon U-Pb ages, and rare earth elements. Our study reveals that the Donghetang Formation belongs to the coastal-shallow sandy coastal phase. The zircon U-Pb ages are distributed into three groups: 485-393 Ma, 995-665 Ma, and 2064-1560 Ma. Heavy minerals and detrital zircon data show that the host rocks are primarily composed of acidic magmatism, with a smaller presence of intermediate-basic magmatism or granitic pegmatites. The sources of the Donghetang Formation are primarily attributed to the West Kunlun Orogenic Belt and the Tabei Uplift. By comprehensively determining the sedimentary features, stratigraphic assignment, and source evolution of the Devonian Donghetang Formation in the western Tarim Basin, we can not only provide information on the evolution of the basin, but also provide crucial data support for future oil and gas exploration endeavors.