沐川太平砂岩型铼钼(锇)矿点的地质特征和矿化时代

Geological Characteristics and Mineralization Age of the Sandstone Type Re-Mo(-Os) Mineral Occurrence in Muchuan, Sichuan

四川沐川县民主—太平—带含钼砂岩为一新矿化类型——沉积砂岩型铼钼(锇)矿点。X-射线粉晶衍射分析结果表明其中微—细晶鳞片状含钼矿物为晶质辉钼矿;高精度质谱分析发现辉钼矿中分散元素Re和铂族元素Os含量很高,具有重要的综合利用价值;高精度Re-Os同位素测年证明辉钼矿形成年龄与含矿的中生代红层盆地砂岩同期,未发现任何热液活动迹象或构造活动影响,认为辉钼矿属同生沉积产物。这一发现和研究对于矿物学和矿床学均具有重要的理论意义和应用价值。

Mo-bearing sandstone discovered in the Minzhu-Taiping area, Muchuan County, Sichuan Province, is a new type of mineral deposit-sedimentary sandstone type Re-Mo (-Os) deposit. X-ray powder diffractionanalysis shows that the finely crystalline-microcrystalline scaly Mo-bearing mineral in the ore is crystalline molybdenite. High-precision mass spectrbmetry indicates that the contents of the dispersed element Re and plat-inum-group element Os are high in molybdenite. So the two elements can be recovered for industrial uses. High-precision Re-Os isotope dating suggests that the Muchuan Re-Mo (Os) deposit form in 202~206 Ma, synchroneously with the ore-bearing Mesozoic red bed basin sandstone. No sign of hydrothermal activity or tec-tonic setting has been found. The authors think that the molybdenite is the product of the syngenetic sedimenta-ry period. This discovery and research are of great theoretical significance and practical value for the study of mineralogy and the geology of mineral deposits.