In-situ analysis and genetic investigation of Li-bearing minerals in McDermitt clay-type lithium deposit,Nevada,USA  

作　　者：Yi Cui Hanjie Wen Zhengbing Zhou Kunyue Ling Lin Xu Shirong Liu Fei Xu 

机构地区：[1]School of Earth Sciences,East China University of Technology,Nanchang 330013,China [2]State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China [3]School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China [4]College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China [5]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China [6]State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China

出　　处：《Acta Geochimica》2024年第3期478-488,共11页地球化学学报（英文）

基　　金：This work was financially supported by the National Natural Science Foundation of China(Grant Nos.92162214,41773015,and U1812402);the Key Research and Development Program of Yunnan Province(202103AQ100003).

摘　　要：Clay-type Li deposits are poised to play a pivotal role in addressing the surging global demand for Li.The McDermitt clay-type Li deposit,located in Nevada,is the largest Li deposit in the United States,with Li hosted by a clay-rich sequence of smectite-dominated intervals and illite-dominated intervals,respectively.However,the occurrence of Li and the genesis of Li-bearing minerals within smectite-dominated intervals have not been thoroughly investigated in previous research.Here,we studied the mineralogy,the in-situ Li distribution,and the bonding environments of Li within the smectite intervals using a combination of instru-mental techniques including scanning electron microscope,transmission electron microscope,time-of-flight secondary ion mass spectrometry,and nuclear magnetic resonance.Our results indicate that the smectite exhibits low crystallinity characteristics of lacustrine clay authigenesis and is com-monly found tofill the interstices among volcanic minerals or envelop them;Li is mainly hosted by Mg-smectite rather than the volcanic minerals.Within the tuffaceous sediment samples,the volcanic glass has undergone a transformation,resulting in its complete disappearance and alteration into clay minerals.Owing to the octahedral sites of Mg-smectite bounded in Li,it is referred to be hectorite.We interpret that the hectorite’s precipitation occurs in a high saline-alkaline water environment,a result of McDermitt tuffdissolution.This conclusion can be supported by the coexistence of spherulitic calcite and hectorite.Overall,this study confirms hectorite as the main Li-bearing mineral and increases the understanding of the genetic model of hectorite formation in intracontinental caldera basins.

关 键 词：McDermitt caldera Lithium occurrence Tuffaceous sediments MINERALOGY Hectorite neoformation 

分 类 号：P618.71[天文地球—矿床学]