钴矿床类型划分初探及其对特提斯钴矿带的指示意义

A new division of genetic types of cobalt deposits:Implications for Tethyan cobalt-rich belt

作为一种战略性关键金属,钴的现有矿床类型划分方案存在标准不统一等问题。文章从矿床成因角度提出新的划分方案,认为钴矿床主要有岩浆型、热液型、风化型和化学沉积型4种基本矿床类型。热液型可细分为岩浆热液矿床和盆地流体有关矿床2个亚类型。这一新划分方案对于理解钴矿床成矿作用和指导找矿勘查等方面具有重要启示意义。研究发现热液过程对钴富集成矿具有重要作用,而高盐度流体是钴迁移富集的关键所在。根据盆地流体有关热液钴矿床时空分布规律分析,提出欧亚大陆南缘存在一条上万公里长的特提斯碰撞钴矿带。该带具有得天独厚的金属源区、流体运移和金属沉淀等成矿条件,成矿潜力巨大。

Cobalt is an important strategic metal.However,there exist many problems concerning the division of genetic types of cobalt deposits,which leads to a confused understanding on genesis of cobalt deposits.Here the authors propose a new division mainly based on ore genesis,with which global cobalt resources can be grouped into four basic deposit types,i.e.,magmatic sulfide deposits,laterite deposits,chemical precipitation deposits,and hydrothermal deposits.The hydrothermal deposits can be further divided into two sub-types:magmatic-hydrothermal deposits and hydrothermal deposits formed from basin brines.The new genetic division of cobalt deposits would shed light on ore genesis and help identify new economically significant deposits.The hydrothermal deposits host 49%cobalt metal reserves,supply 62%of the world’s Co production,and are genetically related to highsalinity fluids.All these data prove that hydrothermal process within the crust is important for cobalt deposits,and the high-salinity fluids are vital for cobalt enrichment.The authors hold that there exists a 10000 km cobalt-rich belt within Tethyan collisional orogenic belt based on analysis of the spatial-temporal distribution of hydrothermal deposits formed from basin brines.The Tethyan belt has great potential for cobalt-rich deposits.