泰国沙空那空盆地哇伦钾盐矿区控矿构造条件分析

Study on Ore Controlling Structural Conditions of Walun Potash Deposits in Nakhon Basin,Thailand

为查明哇伦钾盐矿区的控矿条件及矿体特征,进一步布置勘查工作,对矿区开展了重力测量、钻探验证及物探测井等工作。矿区布格重力异常值均为负值,在矿区中部存在一北西向展布的相对高重力异常带,其西南及东北侧则为相对低重力异常区。经钻探验证及地层对比认为该相对高重力异常带为一北西向隆起带,分割出西南和东北两个次级凹陷,东北凹陷较浅且较宽缓,沉积了中下膏盐层,上膏盐层只沉积了薄层的石膏;西南凹陷较深,上中下三个膏盐层发育齐全,同时该隆起对钾盐矿层沉积具有明显的控制作用,钾盐矿仅分布于两个次级凹陷内,在隆起部位只发育两个膏盐层,且未沉积钾盐矿层。综合研究认为,矿区基底构造为北东、南西两个向斜和中部的一个背斜组成的褶皱,控制了区内的地层沉积及钾盐矿的形成,后期的构造运动对矿体的影响轻微。以上工作基本查明了矿区构造特征,深化了对矿区钾盐成矿规律的认识,为勘查工作的布置提供了重要依据。

In order to find out the ore-controlling conditions and ore-body characteristics of the potash deposit and arrange further exploration work,gravity survey,drilling verification and geophysical well logging have been carried out.The Bouguer gravity anomaly is negative in mining area.There is a relatively high gravity anomaly zone spreading north-west in the middle of the mining area,and its southwest and northeast sides are relatively low gravity anomaly areas.Through drilling verification and stratigraphic correlation,it is concluded that the relative high gravity anomaly zone is a north-west basement uplift,dividing two secondary depressions in southwest and northeast,the Northeast Depression is shallow and wide,where the middle and lower gypsum salt layers are deposited,while the upper gypsum salt layer only deposits a thin layer of gypsum;The southwest depression is relatively deep,and the three gypsum(The upper,middle and lower)salt layers are well developed.At the same time,the uplift has obvious control over the deposition of potash deposit.Potash deposit is only distributed in two secondary depressions,and only two gypsum salt layers are developed in the uplift,and no potash deposit is deposited.The comprehensive study shows that the basement structure of the mining area is a fold composed of two synclines in northeast and southwest area and one anticline in the middle,which controls the formation of strata deposition and potash deposit in the area,and the later tectonic movement has little influence on the ore body.The above work has basically found out the structural characteristics of the mining area,deepened the understanding of the law of potassium salt mineralization in the mining area,and provided an important basis for the arrangement of the exploration work.