| Origin of Halite in the Lanping–Simao Basin, Southeastern Tibetan Plateau, China: Evidence from Sr and Cl Isotopes |
| |
| 引用本文： | DU Shaorong,ZHENG Mianping,Lü Yuanyuan,ZHANG Yongsheng,ZHANG Xuefei,MIAO Zhongying,LI Mingming.Origin of Halite in the Lanping–Simao Basin, Southeastern Tibetan Plateau, China: Evidence from Sr and Cl Isotopes[J].Acta Geologica Sinica,2022,96(6):2028-2039. |
| |
| 作者姓名： | DU Shaorong ZHENG Mianping Lü Yuanyuan ZHANG Yongsheng ZHANG Xuefei MIAO Zhongying LI Mingming |
| |
| 摘 要： | The Lanping?Simao Basin is located on the southeastern Tibetan Plateau, China, and contains massive evaporites. The origin of evaporites in the basin has been hotly debated because of the strong transformation by tectonic movement. Forty halite samples from borehole MK-3 in the Mengyejing area of the basin were collected and analyzed using XRD, Cl-Sr isotopes and chemical compositions to trace the origin of the evaporites in the basin. The Br × 103/Cl ratios of the halite samples are between 0 and 0.55, most of which are synchronized with the law of seawater evaporation and at the stage of halite precipitation from seawater, indicating that the evaporites are mainly of marine origin. The 87Sr/86Sr ratios range from 0.707489 to 0.711279; after correction, the 87Sr/86Sr 145 Ma ratios range from 0.704721 to 0.707611, equivalent with the 87Sr/86Sr ratios of seawater at 145 Ma, indicating a marine origin. The decay of 87Rb in the evaporite during deposition, change of the depositional environment and the unsealed environment at a later period resulted in the present 87Sr/86Sr ratios of some samples being high. The δ37Cl value compositions range from ?0.38‰ to 0.83‰, which is consistent with the δ37Cl value composition of the world marine halite (?0.6‰ to 0.4‰), further confirming that seawater is the main origin. In addition, the high δ37Cl value of some samples at the boundary of the upper and lower evaporite layers might be related to the influence of δ37Cl-rich brine and the incomplete dissolution of the halite.
|
| 关 键 词： | evaporites halite potash Cl-Sr isotopes Lanping–Simao Basin |
| 收稿时间： | 2021/12/20 0:00:00 |
| 修稿时间： | 2022/5/30 0:00:00 |
|
| 点击此处可从《Acta Geologica Sinica》浏览原始摘要信息 |
| 点击此处可从《Acta Geologica Sinica》下载免费的PDF全文 |
|
