| 摘要: |
| 为了解不同类型含金属沉积物在物质组成和元素赋存状态的差异, 对东太平洋海隆13°N洋中脊两侧表层含金属沉积物(站号: E271和E53)进行了矿物学、地球化学分析, 顺序提取实验, 并与前人对轴部表层沉积物(站号: 17A-EPR-TVG1)的研究结果作了对比分析。研究结果表明, E271和E53是远端含金属沉积物, 由非浮力热液羽状流中颗粒物沉降所形成的; 17A-EPR-TVG1沉积物是近喷口含金属沉积物, 由黑烟囱或者热液硫化物丘状体崩塌、堆积, 或者由热液羽状流中Fe-Mn氧化物和硫化物快速沉淀而形成的, 近喷口沉积物比远端沉积物更富集Fe、Cu和Zn等元素。元素在两种含金属沉积物中的赋存状态基本相同, 除了Fe, Cu, Zn, Mo和稀土元素(REE)等元素在远端沉积物中主要存在于Fe-Mn氧化物相, 在近喷口沉积物中主要在残留相中。远端沉积物中REE页岩标准化配分模式与海水相似, 表明REE 主要来自海水, 而近喷口沉积物中REE配分模式与热液流体相似, 说明REE以高温热液流体来源为主。相关研究结果加深了对热液沉积作用研究的认识。 |
| 关键词: 东太平洋海隆 含金属沉积物 顺序提取 元素赋存状态 |
| DOI：10.11759/hykx20170925002 |
| 分类号: |
| 基金项目:国家自然科学基金(41325021); 国家重点基础研究发展计划(973 计划)(2013CB429700); 国家大洋重大专项课题(DY125-12-R-02);山东省泰山学者专项基金(ts201511061); 青岛海洋国家实验室鳌山卓越科学家人才专项(2015ASTP-0S17) |
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| Composition and element occurrence states of recent metalliferous sediments from the East Pacific Rise at 13°N |
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RONG Kun-bo,ZENG Zhi-gang,WU Li,LI Kang
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| Abstract: |
| This study was conducted to better understand differences in compositions and element occurrence states between near-vent and distal metalliferous sediments on the East Pacific Rise (EPR) at 13°N, using mineralogical, geochemical analysis sequential leaching experiments and comparison with the previous study on the axial surface sediment (site 17A-EPR-TVG1). Sediment samples collected from two sites, E271 and E53, along the ridge flank on both sides of the EPR are distal metalliferous sediments that result from hydrothermal non-buoyant plume fallout. However, samples (site 17A-EPR-TVG1) from the slope of a hydrothermal mound on the EPR axis are near-vent metalliferous sediments that are formed by mass-wasting and erosion of sulfide edifices, and hydrothermal plume fallout of sulfides. In terms of sequential leaching, while Fe, Cu, Zn, Mo, Y, and Rare Earth Element (REE) are mainly present in the residual fraction of near-vent sediments, they mainly occur in the Fe-Mn oxide fraction of distal sediments. Although a large part of pyrite is oxidized in near-vent sediments, the shale-normalized REE distribution pattern of the sediments shows a peculiar positive Eu anomaly similar to those of hydrothermal fluids, suggesting a hydrothermal origin, but those of distal sediments show Ce depletion, characteristic of seawater. The conclusion can deepen the understanding of hydrothermal sedimentation. |
| Key words: the East Pacific Rise metalliferous sediments sequential leaching element occurrence states |
