摘要
近几年以来,由于铼-锇同位素体系逐渐应用于基性-超基性岩有关的岩浆型矿床中,对这类矿床的成矿物质来源有了更为深刻的认识。许多过去被认为是由幔源物质形成的岩浆型矿床(例如Bushveld、Sudbury等),其实地壳物质占有相当大的比例。同时,由于铼-锇同位素体系揭示了源于地壳之放射性成因锇的存在,新的成矿观点也就应运而生。例如,一些学者用热液成矿作用来解释Bushveld矿床中地壳成因的锇同位素特征;陨石撞击成因被再次用来解释Sudbury的成因,因为陨石撞击能有效提供形成Sudbury复式岩体所必须的地壳物质(地壳物质所占比例大于60%)。
The application of the Re-Os system into the typical magmatic ore deposits hasindicated the complex ore-forming sources for this type of deposits which used to be con-sidered to have been solelv derived from the mantle, The analvtical results from importantdeposits such as Bushveld,Sudbury,Noril'sk imply that they have a considerable portionof the crustal materials.The crustal materials may be incorporated into these deposits ei-ther by mixing/assimilation or hydrothermal processes.
出处
《地学前缘》
EI
CAS
CSCD
1994年第4期199-203,共5页
Earth Science Frontiers