论文部分内容阅读
四川盆地上三叠统须家河组以超稳定型重矿物为主,不同层段重矿物组成差异不大。重矿物分析不仅有利于沉积体系及古水系的准确恢复和对远景区油气储层的准确预测,而且还可揭示龙门山等物源区的岩石—大地构造属性及其隆升历史。Q型聚类分析和主因子分析表明,须家河组母岩以沉积岩和低级变质岩为主,高级变质岩含量相对较低。由下至上,母岩中高级变质岩含量逐渐增加。ZTR指数分析表明,晚三叠世四川盆地主要发育4个物源,分别位于川西南部、川西北部、川东北部和盆地东南,物源分布位置具有继承性。结合造山带和前人沉积学研究成果认为,晚三叠世,龙门山褶皱带开始逐渐形成。须二期,龙门山北段已露出水面遭受剥蚀,但龙门山南段仍是水下隆起或尚未隆升。须四期,龙门山北段继续隆升遭受剥蚀,龙门山南段开始抬升遭受剥蚀,并向盆地提供物源。须六期,龙门山地区全面抬升遭受剥蚀,并向盆地提供物源。
The Upper Triassic Xujiahe Formation in Sichuan Basin is dominated by ultra-stable heavy minerals, with little difference in the composition of heavy minerals in different layers. Heavy mineral analysis is not only beneficial to the accurate recovery of sedimentary system and paleo-water system and the accurate prediction of oil and gas reservoirs in the vistas, but also reveals the rock-to-tectonic attribute and its uplifting history in provenance areas such as Longmenshan. Q-type cluster analysis and principal factor analysis show that the parent rocks of Xujiahe Formation are mainly sedimentary rocks and low-grade metamorphic rocks, while the contents of high-grade metamorphic rocks are relatively low. From bottom to top, the contents of high-grade metamorphic rocks in parent rocks gradually increase. ZTR index analysis shows that there are mainly four provenances in the Late Triassic Sichuan Basin, which are located in the southwestern part of Sichuan, northern part of Sichuan, northeastern Sichuan and the southeast of the basin, respectively. Based on the study of orogenic belt and predecessor sedimentology, the Late Triassic and Longmen Shan fold belt began to form gradually. To be Phase II, Longmen Shan northern section has been exposed to erosion of the water surface, but the southern section of Longmen is still underwater uplift or not yet uplift. After four periods, the northern part of the Longmenshan Mountains continued to rise and suffered erosion. The southern part of the Longmen Mountains began to rise and be eroded to provide resources for the basin. After six periods, the Longmenshan area was fully uplifted and subjected to erosion, and the provenance was provided to the basin.