多参数约束剖析柴达木盆地砂西地区古近系沉积物源

Analysis on the sediment provenance of Paleogene through multi-parameter constraints in Shaxi area, Qaidam Basin

徐良佳 于胜尧 纪文涛 高翔宇

中国海洋大学海洋地球科学学院，山东 青岛 266100 青岛海洋科学与技术国家实验室海洋地质过程与环境功能实验室，山东 青岛 266037

College of Marine Geosciences, Ocean University of China, Qingdao 266100, China Laboratory for Marine Geology and Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266037, China

柴达木盆地新生界多物源体系是沉积学研究的热点问题之一，且一直存有争议。文中运用重矿物、稀土元素、单砂体沉积学等方法，剖析了该盆地砂西地区下干柴沟组下段沉积物源及其与邻区的关系。结果表明：砂西地区与来自阿尔金山物源的红柳泉及七个泉地区在重矿物组合及稀土元素分配模式方面存在明显差异，而与尕斯、跃进地区相似；重矿物稳定系数平面分布及单砂体展布特征显示砂西地区古水流方向为SW至NW。综合分析认为，砂西地区下干柴沟组下段物源来自西南方向的铁木里克凸起。该研究对重新理解古新世柴达木盆地古地理格局及提高储层预测准确率具有重要意义。

The Cenozoic multi-source system in the Qaidam Basin is one of the hot issues in sedimentology research, and it has always been controversial. By means of heavy minerals, rare earth elements, and single sand body sedimentology, this paper tries to find out the sediment provenance of Lower Member of Lower Ganchaigou Formation in Shaxi area and its relationship with neighbouring area. The results show that, in heavy mineral combination and rare earth element distribution patterns, Shaxi area has obvious differences with Hongliuquan and Qigequan area whose sources are from Altun mountains, but similar to Gasi and Yuejin regions. Moreover, distribution of heavy mineral stability coefficients and the distribution characteristics of a single sand body indicate that the paleo-current direction in Shaxi area is from southwest to northeast. Comprehensive analysis shows that provenance of Lower Member of Lower Ganchaigou Formation in Shaxi area comes from Tiemulike uplift in southwest direction. This research is of great significance for re-understanding the paleogeographic pattern of the Paleocene Qaidam Basin and improving the accuracy of reservoir prediction.

10.6056/dkyqt202203008