呵叻高原农波盆地龙湖钾盐矿床特征及其形成的古环境条件

Characteristics of the Longhu potash deposit and its paleoenvironment conditions for mineralization

位于藏滇印支地槽褶皱系南段印支中间地块呵叻高原北部沙空那空盆地东南缘的农波盆地在古新世发生3次沉积旋回,钾盐矿体主要产于第一沉积旋回形成的下岩段膏盐岩层上部,第二、第三沉积旋回沉积成盐时期较短、盐类矿产沉积厚度较薄,未形成工业意义的钾盐矿体,只在局部地段形成了钾盐矿化。龙湖矿区钾盐矿矿石类型主要为钾石盐矿、光卤石矿,钾盐矿矿体剖面结构为下部原生钾石盐,中部为厚层的光卤石矿层,上部为次生淋滤形成的钾石盐。下部原生钾石盐矿,呈薄层状出现,连续性差;光卤石矿矿层厚而连续,KCl含量高,KCl(分子总量)>MgCl(分子总量),存在独立的钾石盐矿物;上部钾石盐矿受后期地质作用改造厚度变化较大,盐背斜轴部较厚,两翼较薄。

In the Paleocene, sedimentary cycles happened three times in the Nongbo basin, which lies in the southeastern margin of the Sakhon Nakhon Basin, the northern part of Korat Plateau, the middle part of the southern Indo-China area of the Indo-Tibetan geosynclinal fold. Potash ore was mainly formed in the upper part of the Gypsum rock under the rock section which are formed in the first sedimentary cycle, the salt for- mation period of the second and the third sedimentary cycle is shorter, and the sediment thickness of salt mineral resources is thinner, it didn＇t form a meaningful industrial sylvite solid ore, only formed sylvite min- eralization locally. The main ore types of potash salt ore in the Longhu orefield is sylvite ore and carnallite, the lower part of the section structure of potash salt ore body is original sylvite, the central part is thick-bed- ded and continuous carnallite ore deposits, the upper part is secondary leached sylvite. The original sylvite in lower part occur in thin layer, with poor continuity~ the carnallite ore deposits is thick and continuous, and the KC1 content is high, KCI （molecular volume）〉 MgC1 （molecular volume）, there are independent sylvite minerals; the thickness of sylvite ore in upper is relatively large by reformation during late geological proces- ses, the axis of salt anticline is thick, and two wings are thin.