摘要
锂作为新能源的关键金属,其富集机制与沉积环境研究对资源勘探至关重要。本文以鄂尔多斯盆地东南缘本溪组富锂黏土岩为研究对象,通过X射线衍射(XRD)、扫描电镜(SEM)及地球化学分析,以期系统揭示该黏土岩的矿物组成及沉积环境对锂元素富集的影响。结果表明,岩样以伊利石、高岭石和硬水铝石为主,锂含量超常富集(850×10^(-6)~5860×10^(-6)),Sc、Th、Ga及轻稀土元素富集,Ba、Rb、Zn亏损。沉积环境经历海陆过渡相动态演变,强化学风化(CIA=84.64~99.82)与湿热气候(古水温30℃)促进了含Li母岩的分解并释放Li^(+);多期海侵-海退旋回形成了氧化-还原界面交替的沉积环境,海退期(氧化)黏土矿物吸附主导Li富集,海侵期(还原)黄铁矿生成抑制吸附,过渡阶段脱硅富铝作用调控Li^(+)再分配。物源主要来自后太古宙长英质岩石(阴山古陆)与沉积岩(北秦岭)。
Lithium is a critical metal for new energy.To study its enrichment mechanism and sedimentary environment is vital for its resource exploration.This study investigates lithium-rich claystones in the Benxi Formation in the southeastern margin of the Ordos Basin by using the XRD,SEM,and geochemical analytical methods,in order to elucidate the influence of mineral compositions and sedimentary environment of the claystone on the Li enrichment.The results indicate that the claystones,mainly consist of illite,kaolinite,and diaspore,have ultrahigh Li concentrations(850×10^(-6)~5860×10^(-6)),enriched Sc,Th,Ga,and light rare earth elements(LREE),and depleted Ba,Rb,and Zn.The sedimentary environment of the claystone underwent dynamic evolution of the transition from marine to land facies.The intensive chemical weathering(CIA=84.64~99.82)and hot-humid climate(paleo-water temperature of 30°C)facilitated the decomposition of Li-bearing parent rocks and the release of Li^(+).The multi-stage marine transgression-regression cycles resulted in the sedimentary environment with alternating oxidation-reduction interfaces.The Li enrichment was facilitated dominantly by the adorption of clay minerals during the marine regression stage(oxidizing),but it was inhibited by the pyrite formation under reducing condition during the marine transgression stage,and the Li redistribution was controlled by the desilication-aluminization process during the transitional stage.It is believed that materials of the claystones could be mainly sourced from the post-Archean felsic rocks in the Yinshan Paleocontinent and sedimentary rocks in the North Qinling.
作者
邸思佳
张贵山
温汉捷
王亮
常旺
李雨蒙
张磊
DI Si-jia;ZHANG Gui-shan;WEN Han-jie;WANG Liang;CHANG Wang;LI Yu-meng;ZHANG Lei(School of Earth Science and Resources,Chang’an University,Xi’an 710064,China;Engineering Technology Innovation Center of New Energy Minerals and Resource Information,Ministry of Natural Resources,Xi’an 710064,China)
出处
《矿物岩石地球化学通报》
北大核心
2025年第5期1081-1095,共15页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
云南省重点研发计划(202103AQI00003)
贵州省科技计划项目(黔科合战略找矿[2022]ZD002)。
关键词
鄂尔多斯盆地
本溪组
富锂黏土岩
地球化学
沉积环境
Ordos Basin
Benxi Formation
lithium-rich claystone
geochemistry
sedimentary environment
