RARE EARTH ELEMENT GEOCHEMISTRY OF Co-RICH CRUST IN THE MID -PACIFIC AND SOUTH CHINA SEA
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摘要: 对中太平洋海山和中国南沙海盆富钴结壳中稀土元素的含量、分布特征、配分模式分析结果表明:富钴结壳中稀土元素含量非常高,总量为1 380×10-6~2 360×10-6,约为正常深海沉积物和海水中稀土元素含量的10~100倍,与大陆地壳丰度相比Ce最为富集;中太平洋海山区和中国南沙海盆富钴结壳中的稀土元素配分模式与其他海域基本相同,属轻稀土元素富集、重稀土元素亏损型;Ce元素含量和轻重稀土元素的比值沿生长方向逐渐降低,底层比顶层高出近一倍;不同海域富钴结壳中稀土元素的含量变化较大,夏威夷群岛富钴结壳中的稀土元素总量最高,中太平洋海山区中等,中国南沙海盆偏低。Abstract: The rare-earth element (REE) concentrations of Co-rich crust from the Central Pacific Ocean and South China Sea were determined using chemical-digest ICP-MS method. This paper discusses the REE abundance, distribution features in different layers,and REE participation patterns of Co-rich crust. Our research results indicate that:(1) The REE concentrations in Co-rich crusts of the Central Pacific and South China Sea are distinctively high, and REE content varies between 1380×10-6~2360×10-6, 10~100 times higher than the REE concentration of crusts from water sediment and seawater. (2) The REE participation patterns of research area and other sea area are similar. The TREE is relatively enriched and the HREE is in relative depletion. (3) Content of Ce and ∑Ce/∑Y is decreasing along the growth layer of the Co-rich crust (from bottom to top). (4) Different sea areas have great differences in REE concentrations of Co-rich crusts. REEs in Co-rich crust are the highest in the Hawaiian Islands, and the lowest in the South China Sea, with those of the Mid-Pacific seamounts in between.The rare earth element distribution characters indicate that ocean environment for Co-rich crust growth is different from each other in different seamounts.
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Key words:
- Co-rich crust /
- rare earth element /
- Central Pacific /
- South China Sea
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