青海大风山天青石矿床地质特征及成因分析

Characteristics and Genetic Analysis of Celestite Deposits in Dafeng Mountain Area,Qinghai

大风山天青石矿床位于柴达木盆地西北部,由Ⅰ、Ⅱ、Ⅲ、Ⅳ四个矿区组成,赋矿地层为第三系上新统狮子沟组,含矿层位不稳定,矿体多呈薄层状、扁豆状或透镜状产于含碳钙质泥岩中,矿石主要为天青石、菱Sr矿等;矿区内东西、北东东向次级断裂及舒缓短轴复式背斜构造严格控制着天青石矿体的产出形态;成矿物源具有多源性,一方面周边山系含Sr水为主要补给源,其次为富Sr的油田水。另外,深部含Sr卤水的补给也具有重要作用;矿床成因具有陆相湖泊化学沉积-热水沉积叠加改造型矿床特征。

Celestine deposit of Dafeng mountain is located in northwestern of Qaidam Basin, it is composed of I , II , III, IV four deposits, and ore-formation is Shizigou group of the Pliocene in Tertiary strata, with seam-bit of unstable ore, ore body mostly by thin-bedded, lens-shaped or lenticular produced in carbon-bearing calcareous mudstone, and ore mainly for celestite, strontianite, etc. The EW, NEE sec- ondary faults and the compound anticline with relieve minor axis strictly controlled the celestite ore output patterns in the Dafeng mountain ore area. Strontium-containing material source of mineralization is with multi-source in the area. On the one hand, water with strontium of the surrounding mountains is the main supplying source; on the other hand, water with oil fields of strontium-rich is supplying source too. In ad- dition, brine with strontium in the deep crust plays an important role as supplying source; Genesis have the characteristics by continental lake chemical deposition-hydrothermal sedimentary superimposed trans- formation type in the Dafeng mountain area.