从自贡盐矿地球化学特征成盐模式看其找矿方向及含钾性

GEOCHEMICAL CHARACTERISTICS AND SALT-FORMING PROCESSES OF ZIGONG SALT MINE: CONSTRAINTS ON ORE-HUNTING DIRECTION AND POTASH-FORMING PROPECTS

自贡自流井构造盐矿规模小,呈透镜状,厚度薄,变化大。但盐矿咸化程度高,盐溶水K+、Mg2+含量高;K·103/Cl、K/Br、Br·103/Cl地球化学特征优异。盐矿为潮上蒸发坪上预为浓缩的古卤水聚集于相对低凹的盐沼,再经蒸发而形成,具有成钾条件。盐矿受蒸发坪古地貌控制。在古地貌低洼处及“X”棋盘格式构造交叉处、TM遥感图象上环形影象的点,部署钻探验证,可望找到新的盐矿体。这为进一步开展自流井构造探盐找钾工作可具有重要现实指导意义,对其它地区也有一定启示意义。

Salt mines with brine channeled up by artisian wells in Zigong district are generally typical of small-sized, lense-like, thickness varying, salt bodies. Nevertheless, the bodies are known for a high salinity, high contents of K+ and Mg2+', and desired geochemical ratios of K· 103/C1, K/Br, and Br· 103/Cl, after water solving, and for good potash-forming conditions, as they are as a result of evaporation of previouly densed brine restricted to relatively low-lying pools on suprotidal zones. Intensity of evaporation is strongly controlled by suprotidal land forms, such as old depressions, intersections of checkerboard topographies, and circular forms reflected by TM remote-sensing images, where if conducting drill hole validation, there will be chance to localize new bodies. These arguments will direct the further development of prospecting for salt ore suitable to artisian well mining not only in Zigong district but elsewhere in the country.,