| 老挝东泰钾盐矿床地球化学及其沉积后变化初步研究 |
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| 引用本文：张西营,马海州,谭红兵,高东林,李斌凯,王明祥,唐启亮,袁小龙.2010.Preliminary studies of on geochemistry and post-depositional change of Dong Tai potash deposit in Laos[J].Mineral Deposits,29(4):711~721 |
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| 基金项目:本文得到国家自然科学基金项目（批准号：40903014和40603007）和中国科学院知识创新工程重要方向项目（编号：KZCX2_YW_344）的联合资助 |
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| 中文摘要:呵叻高原是世界上最大的钾盐沉积矿床分布区之一，研究区位于呵叻高原北部的沙空那空盆地东部边缘，钻探资料揭示该地区钾盐资源相当可观。该含盐建造包含上、中、下3个盐段，每个盐段都由一套蒸发岩_碎屑沉积旋回组成，钾盐层主要赋存于下盐段上部。剖面和地层学分析表明，研究区盐构造类型为低结构低成熟度的盐背斜构造，盐体几何形态为一低结构低成熟度的盐背斜，盐背斜轴部矿层厚度较两翼矿层厚得多。岩盐中微量元素Br、K含量及Br×1 000/Cl系数的变化指示成盐卤水经过了阶段性的浓缩和淡化过程，并且成盐作用越来越弱。ZK04孔较低的Br含量w(Br)=18×10-6表明下膏盐层在成盐过程中受到了非海相流体的影响。中膏盐层基底石盐中高K低Br特征表明，下膏盐层残余高浓度卤水影响了其成盐过程，并且该基底石盐很可能又经历了溶解和重结晶过程。 |
| 中文关键词:地质学 盐体几何形态 微量元素Br和K Br×1 000/Cl系数 沉积后变化 老挝东泰钾盐矿床 |
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| Preliminary studies of on geochemistry and post-depositional change of Dong Tai potash deposit in Laos |
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| Abstract:The study area lies in the eastern margin of Sakon Nakhon Basin within Khorat plateau where there exists one of the world'slargest potash deposits. The data from boreholes reveal the existence of abundant potash. The evaporite-bearing formation comprises three members (Lower, Middle and Upper) which are mainly composed of evaporite separated red-colored siliciclastic rocks. The potash layer exists in the uppermost part of the Lower Member. In the light of an analysis of sections and strata, the salt tectonic type in this area is a low-structure and low-maturity anticline which is closely related to differential loading. The existence of salt tectonics influences not only the distribution and thickness of potash but also the geochemical characteristics of rock salts. The content of minor elements Br and K as well as the Br×1 000/Cl ratios indicate that the brine experienced stages of concentration and freshening, with the salification becoming more and more weak. Low Br content (18×10-6) in rock salt of borehole ZK04 shows that the salification in the Lower Member was affected by non-marine fluids. The basal halites of the Middle Member rich in K and depleted in Br show that infiltrating of the remained concentrated brine from the Lower Member and resolving and recrystallizing of the basal halite. |
| keywords:geology, geometric shape of salt body, bromine and potassium of trace elements, Br×1 000/Cl ratios, post-depositional change, Dong Tai potash deposit of Laos |
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