老挝万象通芒矿区成盐期元素地球化学特征研究  

Study of Geochemical Characteristics of Salt Deposits during Halogeneses in Tongmang Mining Area,Vientiane,Laos

作　　者：唐启亮[1] 张西营[1] 苗卫良[1,2] 李永寿[1,2] 

机构地区：[1]中国科学院青海盐湖研究所,青海西宁810008 [2]中国科学院大学,北京100049

出　　处：《盐湖研究》2013年第3期10-16,共7页Journal of Salt Lake Research

基　　金：国家重点基础研究发展计划项目(2011CB403004);国家自然科学基金项目(40903014)

摘　　要：呵叻高原是世界上最大的钾盐矿床之一,老挝万象盆地是呵叻高原北部沙空那空盆地的一个次级盆地,通芒矿区则是万象盆地钾盐矿床的重要组成部分。近期,大量钾盐地质勘探工作的实施为该地区钾盐沉积的研究提供了良好条件和物质基础。研究表明,含盐地层包括上、中、下3个盐段,巨厚钾镁盐主要富集在塔贡组下盐段。盐类矿物主要包括石盐、光卤石、钾石盐、水氯镁石、溢晶石、硬石膏等,还包括一些碳酸盐和硼酸盐矿物。矿石类型以光卤石矿为主。含盐层位的Br含量、Br×103/Cl比值在剖面上的变化指示了成盐期卤水不断蒸发浓缩,最终形成了具有重要经济价值的钾镁盐矿床。与世界其它海相及陆相钾盐矿床对比表明,通芒矿区钾盐沉积具有明显的海相特征,成盐成钾物质应该来自海水。The potash deposit on Khorat Plateau is among the largest ones in the world. The Vienfiane Ba- sin is one of suhhasins of Sakon Nakhon Basin which is in the north of Khorat Plateau. Whereas the Tong- mang mining area is an important part of Vienfiane potash deposits. A large of geological explorations con- ducted in study area recently provided good conditions and substantial bases to study potash deposit in study area. Study results show that the salt-containing strattim comprises of three sections of upper, middle and lower unit. The voluminous K-Mg salts mainly are enriched in the lower unit. The main salt minerals include halite, carnallite, sylvite, bischofite, tachyhydrite, anhydrite, etc. Additionally minor carbonates and borates were found in these salts. The dominant ore type is the carnallifite type. The variations of bro- mine contents and Br × 103/Cl ratios in profile indicate that the brines have continuously been evaporated and concentrated during halogeneses and eventually formed K-Mg salt deposits with significantly economic values. Comparing with other marine or nonmarine potash deposits, the Tongmang potash deposit has an obvious marine signature. Therefore,it is concluded that these salts in study area should be derived from seawater.

关 键 词：万象盆地 通芒矿区 钾盐沉积 元素地球化学 海相成因 

分 类 号：P596[天文地球—地球化学]