The tempo-spatial characteristics and forming mechanism of Lithium-rich brines in China

With the technological development of exploitation and separation,the primary source of lithium has gradually changed from ore to brine,which has become the main raw material,accounting for more than 80% of the total production.Resources of lithium-bearing brine are abundant in China.This paper has summarized the spatial and temporal distribution,characteristics,and formation mechanism of the lithium-rich brine in China,aiming to provide a comprehensive set of guidelines for future lithium exploitation from brines.Lithium brines usually exist in modem saline lakes and deep underground sedimentary rocks as subsurface brines.The metallogenic epoch of China's lithium-rich brine spans from the Triassic to the Quaternary,and these brines exhibit obvious regional distribution characteristics.Modem lithium-rich saline lakes are predominately located in the Qinghai-Tibet Plateau.In comparison,the subsurface lithium-rich brines are mainly distributed in the sedimentary basins of Sichuan,Hubei,Jiangxi,and the western part of the Qaidam Basin.Lithium-rich saline lakes are chloride-enriched,sulfate-enriched,and carbonateenriched,while the deep lithium-rich brines are mainly chloride-enriched.On the whole,the value of Mg/Li in deep brine is generally lower than that of brine in saline lakes.The genesis of lithium-rich brines in China is not uniform,generally there are two processes,which are respectively suitable for salt lakes and deep brine.

Palynology and stratigraphy of the thick evaporate-bearing Shashi Formation in Jiangling Depression,Jianghan Basin of South China,and its paleoclimate change

In the greater inland Jianghan Basin of South China,three salt depressions are lacking accurate geological times,of which Jiangling Depression is the largest.Evaporites are important records of paleoclimate,however,the geological ages of evaporates are very difficult to be determined because often evaporates have scare macrofossils and microfossils.Nonmarine Cretaceous to Tertiary halite deposits interbedded with mudstones are widely distributed in China.Paleocene-Eocene Thermal Maximum had very high temperatures and attracted strong interests of geologists because these times can be compared with future climate change because of global warming.However,previous studies focused on marine sediments found that during the Paleocene-Early Eocene,massive evaporate deposits formed in Jiangling depression of the Jianghan Basin.In this paper,the authors show that the Shashi Formation halite deposits formed in the Paleocene according to palynology.Most of these palynology fossils are arid types,so the massive evaporites in the Jiangling depression could be closely related to the hot Paleocene climate.High temperatures during the Paleocene contributed to the formation of the massive evaporates in the Jiangling Depression,until sylvite was the result.