柴达木盆地中部高Mg/Li盐湖卤水富镁物源探讨  

Discussion on Magnesium-rich Sources of Salt Lake with High Mg/Li Ratio in the Middle Qaidam Basin

作　　者：陈帅 樊启顺[1,2] 钟晓勇 秦占杰 张湘如[1,2,3] 山俊杰 李庆宽 CHEN Shuai;FAN Qi-shun;ZHONG Xiao-yong;QIN Zhan-jie;ZHANG Xiang-ru;SHAN Jun-jie;LI Qing-kuan(Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining,810008,China;Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes,Xining,810008,China;University of Chinese Academy of Sciences,Beijing,100049,China;Hulun Buir Jin-xin Chemical Co.,Ltd,Hulun Buir,021000,China)

机构地区：[1]中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海西宁810008 [2]青海省盐湖地质与环境重点实验室,青海西宁810008 [3]中国科学院大学,北京100049 [4]呼伦贝尔金新化工有限公司,内蒙古呼伦贝尔021000

出　　处：《盐湖研究》2020年第1期52-59,共8页Journal of Salt Lake Research

基　　金：国家自然科学基金(41872093);青海省创新平台建设专项(2020-ZJ-T06)。

摘　　要：为了查清那棱格勒河尾闾盐湖-一里坪、西台、东台和察尔汗盐湖别勒滩区段高Mg/Li卤水富镁的主控因素及成因,系统采集了柴达木盆地那棱格勒河水、流域围岩和尾闾盐湖卤水样品,进行水样、岩样元素含量及矿物组合分析。结果表明,河水阴阳离子含量特征为Na^+>Ca^2+>Mg^2+和Cl^->HCO3^->SO 4^2-;与河水相比,卤水Ca^2+和HCO3^-含量降低,Na^+、K^+、Cl^-和SO4^2-明显富集,二者具有相似的Mg^2+离子含量所占阳离子总量的百分比(~25%);与南海海水和青海湖湖水蒸发曲线对比,卤水的镁含量落在曲线上,说明卤水富镁是由河水输入、蒸发浓缩控制的,而非盆地古湖自西向东浓缩迁移的结果;通过那陵格勒河流域围岩矿物和镁含量分析,发现河水流经的围岩中沉积有含镁矿物(白云石、含镁方解石和阳起石),且镁含量高达0.6%~11.5%,说明高镁的岩石风化溶滤是引起尾闾盐湖卤水富镁的主因。In order to find out the main controlling factors of magnesium-rich in the terminal salt lakes(Yiliping,Xitaijinar,Dongtaijinar,Bieletan section in Qarhan Salt Lake)of Nalenggele River with high Mg/Li ratios,the authors systematically collected river water,brine and surrounding rock samples from Nalenggele River in the middle Qaidam Basin,and analyzed element content of water and rock samples,and mineral assemblages of rock samples.The results showed that the contents of anion and cation in river water were characterized by Na^+>Ca^2+>Mg^2+and Cl^->HCO3^->SO4^2-.Compared with river water,Ca^2+and HCO3^-concentrations in brine decreased,and Na^+,K^+,Cl^-and SO4^2-concentrations were obviously enriched,both of river water and brine had similar percentage of Mg 2+in total cations(~25%).Compared with the evaporation curves of waters from South China Sea and Qinghai Lake,the magnesium contents in brine were plotted around both of two curves and the lithium contents were far away from both of two curves,which indicate that magnesium and lithium in brine have different origins and the enriched magnesium is formed by river water input and evaporation concentration.This conclusion is inconsistent with that the high magnesium content in salt lakes in the middle part of the basin being the long-term evolution of ancient lakes in the basin from west to east.Magnesium-bearing minerals(dolomite,magnesia-bearing calcite and actinolite)are present in the surrounding rocks,and the contents of magnesium ranged from 0.6%-11.5%.The weathering and leaching of high-magnesium minerals may account for magnesium-rich brine in terminal salt lakes of Nalenggele River.

关 键 词：物源 卤水富镁 柴达木盆地中部盐湖 水化学特征 含镁矿物 

分 类 号：P619.2[天文地球—矿床学]