铂族元素矿床热液流体成矿模型探讨

Hydrothermal fluids and ore genesis of PGE

世界上所有的铂族金属矿床都有热液流体活动的迹象。影响铂族元素(PGE)成矿的流体主要有两类:堆晶体后期流体(>500℃)和岩浆后期流体(<500℃)。低温热液(<500℃)中,PGE可能主要以氯络合物及氢硫基络合物的形式运移;高温热液(>500℃)中,PGE可能主要以氯络合物的形式运移。在详细论述不同温度、压力条件下的热液流体中PGE溶解性质的基础上,分析了PGE在流体中的溶解、迁移、富集及可能的沉淀机制,为探寻PGE矿床的成因提供一个突破口。

Abstract： Almost all of the PGE deposits in the world are associated with hydrothermal fluid activity. In low-temperature fluids （〉 500 ℃）, PGEs are mainly transported as chloro-complex and sulfhydryl-com- plex, whereas in high-temperature （〉 500 ℃） fluids, PGEs exist in the form of chloro-complex. Howev- er, how PGEs concentrate and deposit in fluids are still unclear. In this paper, we have a detailed discus- sion of PGE solubility under different temperatures and pressures, and the mechanisms of how PGEs dis- solve, transport, concentrate and deposit in fluids. This will provide important information for the origin of PGE deposits. Two kinds of fluids are proposed to have an influence on PGE deposits. One is post-cu- mulus fluids （~ 500 ＊C） and the other is post-magmatic fluids （~ 500 ℃）. Post-magmatic fluids usually have complex origins and multi-stage activities, which may hamper the understanding of PGE processes in fluids. We try to investigate PGE behavior in different fluid systems and reveal the significance of hydro- thermal fluids in the ore-forming processes of PGE deposits.