Ore genesis of the lithium-rich brine deposit from Yiliping Salt Lake, Qaidam Basin under dry-cold climate: Evidence from fluid inclusions

The Yiliping Salt Lake in the central part of the Qaidam Basin contains a large amount of lithium-rich brine, and its lithium grade is the highest among the salt lakes in the Qaidam Basin. The ore-forming mechanism of lithium-rich brine in the Qaidam Basin, especially the control of paleoclimate on the evolution of salt lake brine is a hot issue. In this paper, the halite samples from the HC2105 drill hole in Yiliping Salt Lake were selected as the research object, and the halite uranium series dating and halite fluid inclusion homogeneity temperature test were carried out to determine the temperature of the salt lake brine when the halite was precipitated, and to study the relationship between the formation of lithium-rich brine and the ancient Couplings of climate change. Through halite-uranium dating, it is estimated that the upper layer of halite in the HC2105 borehole was deposited at about 40 ka, and the lower layer of halite was deposited at about 120 similar to 100 ka. Through the test of the homogeneous temperature of halite fluid inclusions, the brine temperature of Yiliping Salt Lake during halite precipitation was 8.8-30.1 degrees C, the average temperature was 20.4 degrees C, and the maximum value of all samples was between 21.4-30.1 degrees C, indicating that The brine temperature of the salt lake fluctuates frequently when the halite is precipitated. Combined with the results of halite-uranium dating, it shows that the two obvious cooling processes in Yiliping Salt Lake correspond to the precipitation of halite, indicating that under the overall arid climate environment of the Qaidam Basin, the brine of the salt lake continued to evaporate and concentrate. The occurrence of cooling not only reduces the supply of material sources, but also reduces the solubility of halite, causing a large amount of halite to precipitate, further intensifying the degree of evaporation and concentration of brine, and contributing to the mineralization of lithium-rich brine.

Automated summary

This paper investigates the ore-forming mechanism of lithium-rich brine in the Yiliping Salt Lake in the central part of the Qaidam Basin, China, with a focus on the control of paleoclimate on the evolution of salt lake brine. By conducting halite uranium series dating and halite fluid inclusion homogeneity temperature test, the temperature of the salt lake brine during halite precipitation is determined, and the relationship between the formation of lithium-rich brine and ancient climate change is studied.