广西九毛锡矿床的成矿物理化学条件和锡的迁移形式

Physicochemical Conditions of Metallogenesis And The Hydrothermal Transport of Tin At Jiumao Tin Deposit, Guangxi

本文根据九毛锡矿产出的地质地球化学环境,定量计算了成矿作用的物理化学参数。首次提出并讨论了锡矿的中低温成矿作用,从而打破了锡矿元素只在高温条件下才能成矿的传统观念。成矿作用主要在中低温(260～160℃)热液阶段,压力500×10~5～340×10~5pa,氧逸度log fo_2=-29.2～-42.5,硫逸度log fo_2=-7.7～-19.25,pH=6.1～4.5。运用络合物化学原理和方法,定量计算了成矿流体中锡主要呈羟基络合物形式迁移。

The writer calculated the physicochemical parameters of metallogenesis, depending on geology and geochemistry of Jiumao tin deposit. The results indicate that the yield temperatures are from 405℃ to 160℃, with the main oreforming stage ranging from 260℃ to 160℃, and the oreforming pressure being about 500—340 par,pH, approximately 6.1 to 4.5, and the fugacity of oxygen logfo_2=-29.2～-42.5, the fugacity of sulphur logfs_2=-7.7～-19.25. The middlelow temperature of metallogenesis is discussed. The hydrothermal transport of tin in oreforming fluid fo Jiumao tin deposit is calculated. Depending on the principle and method of complex chemistry, the results of these calculations indicate that most of the tin in solution is present as hydroxide complexes.