Rare earth element distribution in Caribbean seawater: Continental inputs versus lateral transport of distinct REE compositions in subsurface water masses
Rare earth element distribution in Caribbean seawater: Continental inputs versus lateral transport of distinct REE compositions in subsurface water masses
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DOI：
10.1016/j.marchem.2015.03.013
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发表时间：
2015-12
期刊：
影响因子：
3
通讯作者：
Anne H. Osborne;B. Haley;E. Hathorne;Y. Plancherel;M. Frank
中科院分区：
文献类型：
--
作者：
Anne H. Osborne;B. Haley;E. Hathorne;Y. Plancherel;M. Frank
本文分析了加勒比海、墨西哥湾、佛罗里达海峡和靠近奥里诺科河河口的地表水10个站点的全水柱剖面的稀土元素（REE）浓度。结果表明，在靠近奥里诺科河河口的地表水中稀土元素浓度较高，研究区南部和东部富集程度最高，表明河流输入是稀土元素的主要来源，而不是撒哈拉沙尘提供的稀土元素。与潜在的河流源相比，靠近奥里诺科河的地表水富集重稀土元素，强调了河口和表层海洋优先去除轻、中稀土元素的作用。奥里诺科河河口近底水样中相对较小的重稀土富集可能是河流输送沉积物优先释放轻稀土的结果。加勒比盆地不同地下水团块的稀土元素模式基本一致，表明预成型成分的横向输送不受垂直清除和释放过程的显著影响。特别是，低的Dy/Er摩尔比与南极中间水有关，并且很可能是从南大洋平流到加勒比海的。相比之下，与北大西洋上游深水相比，加勒比海深水富含轻稀土和中稀土，这表明下沉颗粒或沉积物的释放是深海中这些稀土的重要来源，特别是当深水停留时间较长时。
The rare earth element (REE) concentrations of full water column profiles from ten stations in the Caribbean, the Gulf of Mexico, and the Florida Straits, as well as of surface waters close to the mouth of the Orinoco River have been analyzed. The results show a high concentration of REEs in surface waters, in particular close to the mouth of the Orinoco, and a middle-REE-enrichment that is strongest in the south and east of the study area suggesting that fluvial inputs are the main sources rather than REEs supplied by Saharan dust. The surface waters close to the Orinoco are heavy REE enriched compared to the potential fluvial sources, emphasizing the importance of processes in the estuaries and the surface ocean that preferentially remove light- and middle-REEs. Relatively small heavy-REE enrichments in near-bottom water samples at the mouth of the Orinoco may be the result of preferential release of light REEs from river-transported sediments. The REE patterns of distinct subsurface water masses are largely coherent across the Caribbean basin, suggesting that the lateral transport of preformed compositions is not significantly influenced by vertical processes of scavenging and release. In particular, low Dy/Er molar ratios are associated with Antarctic Intermediate Water and have most likely been advected into the Caribbean from the Southern Ocean. In contrast, deep waters in the Caribbean are enriched in light and middle REEs compared to incoming Upper North Atlantic Deep Water suggesting that release from sinking particles or from sediments is an important source of these REEs in the deep ocean, in particular when deep water residence times are long.