柴达木盆地东陵湖水化学特征与钾盐分布研究  

Study on water chemical characteristics and potash distribution of Dongling Lake in Qaidam basin

作　　者：石海岩 樊启顺[1,2] 王利文 王明祥 刘万平[6] 李泽仁 李庆宽 陈天源 SHI Haiyan;FAN Qishun;WANG Liwen;WANG Mingxiang;LIU Wanping;LI Zeren;LI Qingkuan;CHEN Tianyuan(Key Laboratory of Green and High-end Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining,Qinghai 810008,China;Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes,Xining,Qinghai 810008,China;University of Chinese Academy of Sciences,Beijing 101408,China;Qinghai Provincial Geological Survey Bureau,Technology Innovation Center for Exploration and Exploitation of Strategic Mineral Resources in Plateau Desert Region,Ministry of Natural Resources,Xining,Qinghai 810001,China;Qinghai Institute of Nuclear Industrial Radioactive Geological Exploration,Xining,Qinghai 810001,China;Qinghai Salt Lake Industry Corporation,Golmud,Qinghai 816099,China)

机构地区：[1]中国科学院青海盐湖研究所,盐湖资源绿色高值利用重点实验室,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,北京101408 [4]青海省地质调查局,自然资源部高原荒漠区战略性矿产勘查开发技术创新中心,青海西宁810001 [5]青海省核工业放射性地质勘查院,青海西宁810001 [6]青海省盐湖工业股份公司,青海格尔木816099

出　　处：《地质学报》2024年第10期2902-2915,共14页Acta Geologica Sinica

基　　金：国家自然科学联合基金重点项目(编号U21A2018)资助的成果。

摘　　要：东陵湖位于柴达木盆地大型钾盐富集基地察尔汗盐湖北部,其浅部石盐层中伴生有光卤石沉积,地勘工作揭示东陵湖浅部边缘地带有寻找低品位固体钾矿的潜力。本文以东陵湖湖表卤水、钻孔晶间卤水、承压卤水、浅层钻孔(0~8 m)盐类沉积物为研究对象,分析研究了东陵湖卤水水化学特征、钻孔沉积物特征及钾盐分布规律,在对比分析察尔汗盐湖钾矿分布特征的基础上,对研究区钾盐成矿作用进行了探讨,主要得出以下结论:①东陵湖周边凹地钻孔的晶间卤水K^(+)平均含量最高(3.19 g/L),其次为凹地钻孔承压卤水(1.46 g/L),湖表卤水(0.74 g/L)和湖区钻孔晶间卤水(0.79 g/L)K^(+)含量较低;东陵湖卤水样品矿化度(TDS)变化范围较大,介于80.63~547.11 g/L之间,不同卤水样品的TDS与K^(+)含量无明显正相关性。②东陵湖钻孔揭露含盐地层厚4.2~6.4 m,岩性以石盐为主,局部含有光卤石沉积,偶见钾石盐;光卤石呈层状和浸染状分布,与石盐呈韵律结构。③东陵湖液体钾矿主要分布于湖区西南侧,卤水K^(+)含量为4.33~6.29 g/L,KCl品位介于0.21%~0.47%之间;固体钾矿主要分布于湖区南侧,沉积物钾含量为2.05%~4.86%,KCl含量介于3.92%~9.29%之间。④东陵湖光卤石沉积区与察尔汗盐湖层状光卤石均沿北缘深大断裂带分布,且后者主要分布于北缘氯化物型水和南缘硫酸镁亚型水混合区域,即达布逊和别勒滩两个洼地北缘,结合Na^(+)、K^(+)、Mg^(2+)、Ca^(2+)//Cl-H_(2)O体系相图和K^(+)-Ca^(2+)相关性分析,认为沿东陵湖南侧深大断裂带补给的Ca-Cl水促进了东陵湖光卤石的沉积。Dongling Lake,located north of the Qarhan Salt Lake,a large potash enrichment zone in the Qaidam basin,exhibits carnallite deposits associated with shallow rock salt layers.Geological exploration indicates the potential for low-grade solid potassium deposits along the lakes shallow periphery.This study investigates the water chemistry,sedimentary features of borehole sediments,and distribution of potassium resources in various brine types(lake surface brines,borehole intercrystalline brines,confined brines)and shallow borehole(0~8 m)salt sediments in Dongling Lake.Additionally,a comparative analysis of potassium deposit distribution in Qarhan Salt Lake is conducted to elucidate the mineralization processes and significance of potassium resources in the study area.Key findings include:①Intercrystalline brines from the sunken borehole area around Dongling Lake exhibit the highest average K^(+)concentrations(3.19 g/L),followed by confined brines in the sunken borehole(1.46 g/L).Lake surface brines and intercrystalline brines from the lake borehole show relatively lower K^(+)concentrations of 0.74 g/L and 0.79 g/L,respectively.Salinity(TDS)in Dongling Lake brine samples varies widely,ranging from 80.63 to 547.11 g/L,with no significant positive correlation observed between TDS and K^(+)concentrations across different brine types.②Borehole analysis reveals salt-bearing strata with thicknesses ranging from 4.2 to 6.4 m,predominantly composed of stone salt with intermittent carnallite deposits and occasional occurrences of potassium salt.Carnallite exhibits a stratified and rhythmic structure alongside the stone salt.③Liquid potassium deposits in Dongling Lake are primarily concentrated in the southwestern region,with K^(+)concentrations in brines ranging from 4.33 to 6.29 g/L and KCl grades from 0.21%to 0.47%.Solid potassium deposits are predominantly found in the southern part of the lake,exhibiting sedimentary potassium contents ranging from 2.05%to 4.86%and KCl contents between 3.92%and 9.29%.④Both the Dongl

关 键 词：钾盐 水文地球化学 分布特征 成矿作用 东陵湖 柴达木盆地 

分 类 号：P619.211[天文地球—矿床学]