云南镇沅地区盐泉水成因与找钾研究

Genesis of Saline Springs and Potassium-prospecting in Zhenyuan Area, Yunnan

中文关键词:  补给源  溶质源  循环演化  找钾异常  热储温度

英文关键词:Recharge source  Solute source  Circulation and evolution  Potassium-prospecting reservoir temperature

中文摘要:

      云南思茅盆地是我国重要的含盐盆地，其南部分布着我国目前发现的唯一具有工业开采价值的勐野井固体钾盐矿床。镇沅地区位于思茅盆地整董含盐带，广泛发育白垩纪蒸发岩、碎屑沉积物及盐泉水。本文通过元素及同位素(δ2H，δ18O，δ37Cl)地球化学指标，系统分析了镇沅含盐带盐泉水水源、溶质来源、热储温度及循环演化模式，探讨了区域成钾潜力。氢氧同位素特征显示，盐泉水源于周边山脉(哀牢山和无量山)雨水和 /或冰雪融水的补给；元素特征显示，盐泉水溶质主要源于卤化物矿物(岩盐)溶滤，部分源于硫酸盐矿物(石膏、硬石膏)及含 Ca碳酸盐矿物(霰石、方解石、白云石)溶滤；稳定氯同位素特征显示，岩盐溶滤是盐泉水的主要 Cl源，大气降水补给及水—岩(火山岩、泥岩和砂岩)相互作用是盐泉水的次要 Cl源；盐泉水热储温度估测范围为 44.3～72.4℃，循环深度估测范围为 914～1 884 m。水化学特征系数显示，盐泉水为岩盐溶滤成因水，含盐地层封闭性较好，变质程度较高。直接及间接找钾指标均显示镇沅地区郭河村及大河边村是找钾异常集中区，可能具有找钾远景。

英文摘要:

      Simao Basin in Yunnan province is an important salt-bearing basin in China. The Mengyejing solid potash deposit is located in the south of Simao Basin，which has uniqe industrial mining value. Zhenyuan area is located in the ZhengDong salt belt of Simao Basin，and cretaceous evaporites，clastic sediments and saline spring water are widely developed in this place. Based on the hydrochemistry and isotopes (δ2H，δ18O，δ37Cl)， this paper systematically analyzed the recharge source，solute source，reservoir temperatures，circulation evo. lution model of saline spring water in Zhenyuan area，and it also discussed the potash exploration prospect instudy area. The hydrogen and oxygen isotope characteristics indicate that the saline springs in this study aremainly derived from meteoric water and/or ice and snow melt from the surrounding mountains (Ailao Mountainand Wuliang mountain).The element characteristics show that the solute source of saline springs is mainly de.rived from the leaching of halide minerals (rock salt)，and partly from the leaching of sulfate minerals (gyp. sum，anhydrite) and Ca-carbonate minerals (aragonite，calcite，dolomite). The stable chlorine isotope charac.teristics show that rock salt leaching is the main Cl source of saline springs，while atmospheric precipitation recharge and water-rock interaction (volcanic rock，mudstone and sandstone) are the secondary Cl sources ofsaline springs. The estimated reservoir temperatures for the saline springs range from 44.3～72.4℃ and its es. timated circulation depths range from 914 m to 1 884 m. The hydrochemical characteristic coefficient showsthat saline springs in this study are of rock salt solution filtrates genetic water，and the salt bearing strata havegood sealing and high metamorphism degree. Both direct and indirect potassium exploration indexes show thatGuohe village and Dahebian Village in Zhenyuan area are abnormal concentration areas for potassium explora.tion，which can be considered to be the most promising areas in search for potash ore.