个旧含锡花岗岩的幔源成因证据

关于个旧含锡花岗岩的成因,过去多数人持“花岗岩内热液充填交代成矿”观点。作者根据该类型矿体的形态、产状和硫同位素特征等,将其归属为印支期海底基性火山—沉积成矿作用后遭受燕山期花岗岩作用后的残余产物。研究结果表明,矿体的形态和产状与外围玄武岩的形态和产状基本一致;黄铁矿样品的σ34S为2.1‰～4.4‰,平均值为3.1‰,数据分布范围狭窄,集中于幔源硫附近,反映了硫的幔源特征。

Genesis Evidengces on Source-of-the-Mantle of Tinny Granite in Gejiu Tin Ore Deposits

Most of researchers for a long time past belived that the genesis of tinny granite in Gejiu tin ore deposits was hydrothermal mineralization in the granite of Yanshanian epoch. However, based on the characteristics of these orebodies such as the form,occurrence and sulphur isotope, authors belive that the genesis of the tin ore deposits is relict body resulted from granitic superimposed ore - forming of Yanshanian epoch after basic volcano ore - forming of Indo - Chinese epoch. The research result has proved that the form and occurrence of these orebodies are basically consistent with that of the basalt of Indo - Chinese epoch. Sulphur isotope contained in pyrite samples is from 2.1 to 4.4 per mille with a mean of 3.1 per mille and narrow range of data distribution, and concentrated near source - of - the - mantle sulphur. These reflect the features of source - of - the - mantle sulphur isotope.