高分辨率光谱学揭示东太平洋CC区结核金属赋存状态及富集机制

赤道东太平洋克拉里昂-克利珀顿带（CCZ）是全球最有经济潜力的结核成矿带，存在巨量的Mn，Co，Ni，Cu，Zn和Li金属资源。前人对CCZ结核的研究偏重化学、矿物学分析，对结核显微纹层、金属赋存状态缺少高分辨率光谱学分析，制约了对金属富集机制的理解。采用扫描电镜（SEM）、X射线衍射仪(XRD)、微区X射线荧光面扫(XRF)、激光剥蚀电感耦合多接受质谱仪(LA-ICP-MS)对克拉里昂-克利珀顿带结核的显微纹层展开高分辨率分析，结果表明结核是由水成层韵律和成岩层韵律交替形成的。水成层由水羟锰矿组成，具有低的Mn/Fe，Li，Ni，Cu，Zn和高的Co，Fe，Ti，V含量，推测受铁的羟基氧化物库仑力吸附作用和高价锰氧化物八面体的表面氧化作用，水成层吸纳高含量Co，Ti和V元素。成岩层矿物组分主要是水钠锰矿，吸纳高含量的Li，Ni，Cu和Zn，其吸纳能力随Mn/Fe升高而提高，当Mn/Fe>8达到峰值。笔者认为结核生长环境中的Mn和Fe相对通量控制了结核的矿物类型和化学组分，而金属通量也可能影响了结核的金属成分。

To Reveal the Occurrence States and Enrichment Mechanisms of Metals in Modules From Clarion-Clipperton Zone in Eastern Pacific by High Resolution Spectroscopy

The Clarion-Clipperton Zone (CCZ) in the equatorial eastern Pacific is the most economically potential nodule metallogenic belt globally. There are huge amounts of Mn, Co, Ni, Cu, Zn and Li metal resources in the CCZ. Previous studies focus on chemical and mineralogical analysis, lacking high-resolution spectroscopy analysis of micro-layers and metal distributions, thus resulting in a weak understanding of the enrichment mechanism of metals. In this study, high resolution scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-area X-ray fluorescence surface scan (u-XRF) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were used to analyze the micro-lamina of nodules. The result shows that the nodule consists of hydrogenic and diagenetic alternating rhythms. The hydrogenic layer comprises Fe-vernadite, yields low Mn/Fe ratio, Li, Ni, Cu, Zn contents, and high Co, Fe, Ti contents. The hydrogenation layer adsorbs high Co, Ti and V contents due to the coulomb adsorption of FeOOH and surface oxidation of the high valence phyllomanganate octahedral layer. The diagenetic layer is birnessite, showing a high Mn/Fe ratio, Li, Ni, Cu and Zn contents. Its absorptive capacity of metals increases with Mn/Fe ratio and reaches its peak when Mn/Fe>8.The author proposes that the relative Mn and Fe fluxes during nodule accretion control the nodule’s mineral type and chemical composition, and the metal flux may also affect the metal composition of the nodule.