中太平洋海山区尖顶和平顶海山结壳成矿与分布的比对研究

摘要

尖顶海山和平顶海山是洋底海山的两种类型,同时也是富钴结壳资源赖以成长的主要载体,两者在地形上具有显著差别,资源状况和分布也不尽一致.以地形分类为基础,就中太平洋海山区两类海山结壳的成矿特征、宏微观构造、矿物和化学组成以及空间分布等进行了比对研究.研究认为,尖顶海山体积虽小,但地形演化连续,底层流及环境氧化性较强,有利于结壳的长期稳定生长,结壳厚度总体较大,富成矿元素和生物组分,远景成矿区域连续绵长.平顶海山山体巨大,顶部和斜坡陡崖区不利于结壳成长,底流活动只在山顶边缘和山脊地带表现突出,环境氧化性整体较弱,后期构造活动相对频繁,结壳总体厚度较小,铁,碎屑和热液组分含量较高,远景矿区相对狭窄.%Conical and flat-topped seamounts are two kinds of seamounts in the ocean, also the main basis on which cobalt-rich crusts grow, with obvious differences in topography, at the same time in the resources status and distribution of the crusts. Based on the classification of studying seamounts, systematic contrast in mineralization characteristics, macrostructure and microstructure, mineral and chemical composition, and space distribution law of crusts of two kinds of seamounts from the central Pacific seamounts are given. The results show that small volume and continuous slope topography raise the oxidizing degree of environment and strengthen the bottom flow intensity of conical seamounts, lead to a larger crusts thickness, more mineral-forming and biogenic elements, so they develop a long continuous mineralized belt. Flat-topped seamounts have a big volume, their top and the cliff of slope make against to growth of cobalt-rich crusts,an area with strong bottom only distributes in the marginal zone of seamounts top and ridge on the slope,the oxidizing degree is low as a whole, they also have relatively frequent tectonic movements, all these bring forth their thinner crusts thickness,Fe, clastic and hydrothermal material contents are higher and perspective mineralized area is narrower than conical seamounts.