四川盆地自贡地区下-中三叠统卤水富锂成因初探

Preliminary Study on the Origin of Lithium Enrichment in Lower Middle Triassic Brine in Zigong Area,Sichuan Basin

本研究主要利用锂元素含量和锶同位素组成特征对四川盆地自贡地区下-中三叠统地下卤水的富锂成因进行分析,查明富锂卤水具有异常高的锶同位素组成特征。在此基础上,结合富锂卤水产出地层层位及岩性特征,认为富锂卤水是卤水与绿豆岩发生水岩反应的产物,卤水的高锂特征源于本身富集锂元素的水云母粘土岩(即绿豆岩)。基于自贡地区卤水的富锂成因,进一步建议富锂卤水的有利勘探层段。

Based on the characteristics of lithium content and strontium isotope composition,this study analyzed the origin of lithium abundance in the Lower-Middle Triassic underground brines in Zigong area,Sichuan Basin.It was found that lithium-rich brines have unusually high strontium isotope composition.On this basis,combined with the lithologic characteristics and stratigraphic sequence of lithium-rich brine,it is concluded that the lithium-rich brines are the product of the water-rock reaction between the brines and mung bean rock,and the high lithium characteristic of the brines is derived from the hydromica clay rock(i.e.mung bean rock)which is rich in lithium element.Based on the origin of lithium-rich brines in Zigong area,the favorable exploration strata of lithium-rich brines are further suggested.