Genesis of Neogene Formation Waters in the Central Qaidam Basin:Clues from Hydrochemistry and Stable D-O-S-Sr Isotopes  

作　　者：HAN Guang PAN Tong LI Qingkuan FAN Qishun HU Yan LIU Jiubo ZHANG Xiying 

机构地区：[1]Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining 810008,China [2]Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes,Xining 810008,China [3]Qinghai Provincial Key Laboratory of Exploration Research of Salt Lake Resources in Qaidam Basin,Qinghai Qaidam Integrated Institute of Geology and Mineral Resource Exploration,Golmud,Qinghai 816099,China [4]University of Chinese Academy of Sciences,Beijing 100049,China [5]Bureau of Geological Exploration&Development of Qinghai Province,Xining 810008,China

出　　处：《Acta Geologica Sinica(English Edition)》2023年第6期1801-1813,共13页地质学报（英文版）

基　　金：supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,Grant No.2019QZKK0805);the Special Project of Qinghai Scholars(Grant No.QHS201802);National Natural Science Foundation of China(NSFC,Grant Nos.41872093,U21A2018);Foundation of Qinghai Science&Technology Department(Grant No.2021-ZJ-932)。

摘　　要：Geological explorations have revealed plentiful Neogene formation waters in anticlines in the central Qaidam Basin(QB).However,the hydrochemistry and origin of these waters are obscure.In this study,the hydrochemistry and DO-S-Sr isotopes of these formation waters were determined to study their origin and evolution.The formation waters are enriched in Na-Ca-Cl,and depleted in Mg-K-SO4-HCO3ions with elevated Li-B-Br-Sr elements.The D-O isotopes prove that the formation waters originated from weak-evaporated meteoric waters,and experienced water-rock interactions.Ion comparisons and Caexcess-Nadeficitdiagrams suggest that solute sources of these waters include evaporite dissolution,waterrock interaction,and minor residual lake brines.Bacterial sulfate reduction and water-rock interactions are supported by the high S-Sr isotopes.The enriched Li-B-Br-Sr concentrations of these waters are in accord with the high geochemical background values of the QB.Regarding the genesis of the formation waters,it can be concluded that meteoric waters from the southern Kunlun Mountains were discharged into the basin,weakly evaporated,and then infiltrated into the Neogene strata through faults leaching the soluble ions and mixing with residual lake brines,and all experienced water-rock interactions and a sulphate reduction process.

关 键 词：HYDROCHEMISTRY brine resources lake/meteoric waters D-O-S-Sr isotopes Miocene-Pliocene Qaidam Basin 

分 类 号：P619.211[天文地球—矿床学]