磷酸盐化对莱恩海山链MP2海山结壳Co富集的影响

摘要

利用电子探针对中太平洋莱恩海山链MP2海山典型富钴结壳样品的剖面分别进行壳层、碎屑矿物和自生矿物主元素原位分析.通过对壳层(主要的成矿金属元素、脉石元素)、碎屑矿物和自生矿物中的Si,Al,Ca和P等元素质量分数的研究,探讨磷酸盐化作用对MP2海山富钴结壳中Co元素富集的影响.发现结壳第Ⅱ层未磷酸盐化壳层存在贫钴壳层,贫钴壳层与磷酸盐化壳层的Co平均质量分数相当,同时发现磷酸盐化壳层(第Ⅲ层)存在Co和P质量分数同步增减的情况,说明富钴结壳磷酸盐化作用不是造成结壳Co质量分数亏损的唯一原因.%A Co-rich Fe-Mn crust was collected in Seamount MP2 of the Line Islands in the Central Pacific and in situ main elements of crustal layers and detrital and authigenic minerals in the crust were analyzed by means of electron microprobe along a section vertical to the layers of the crust. Based on the contents of major ore-forming metal elements, gangue elements and Si,Al,Ca and P in the detrital and authigenic minerals, the effects of phosphatization on enrichment of cobalt in the crust were studied. It has been found that Co is depleted in the non-phosphatized crustal layer (Layer II ), in which the Co content is equivalent to the mean Co content in the phosphatized layers. Furthermore, the Co content at some points in the phosphatized crustal layer (layer Ⅲ ) varies simultaneously with P content. These data indicate that the phosphatization is not the only factor causing the Co depletion in Fe-Mn crusts.