南太平洋富稀土海区海水中的溶解态稀土元素空间分布特征研究

深海富稀土沉积物因其资源潜力巨大,近年来备受关注。一般认为,沉积物中稀土元素和钇（总称REY）的主要来源为上覆海水,但针对富稀土海区上覆海水中REY的研究较少。本研究针对南太平洋富稀土海区采集的3个站位的全水深海水样品,测试出了15种溶解态REY,并对比了邻近海域已发表的数据,分析了该海区REY的空间分布特征。研究区表层水中溶解态REY浓度主要受风尘输入影响,而中层和深层水体中溶解态REY浓度主要受水团控制。经过澳大利亚后太古代页岩（PAAS）和北太平洋深层水（NPDW）归一化后的配分模式可确定REY间的分馏特征,分辨出不同水团。与其他大洋中报道的REY数据比较发现,表层水中REY浓度受风尘和河流输入影响导致差别较大,中层水中REY浓度与印度洋较为接近,深层水中REY浓度与不同大洋的水团年龄表现为正相关趋势,即REY浓度由小到大依次为大西洋、印度洋、南太平洋、北太平洋。

The spatial distribution characteristics of dissolved rare earth elements in seawater of REY-enriched region in South Pacific Ocean

As potential mineral resources, rare earth elements and yttrium (REY)-rich sediments in deep-sea, have attracted a lot of attention in recent years. It is generally believed that the main source of REY should come from overlying seawater, but studies are in general lacking on the REY in overlying seawater in REY-enriched areas. In this paper, the dissolved concentrations and vertical distributions of 15 REY were studied in three stations located in the South Pacific Ocean, where enriched REY concentrations were found in sediments. Data obtained from this study were compared with data reported in adjacent waters and other ocean basins. The REY concentration in surface water of the study area was mainly controlled by wind-driven dust input, while the middle and deep waters were controlled by water masses. After the normalization of Post Achaean Australian Shale (PAAS) and North Pacific deep water (NPDW), the fractionation characteristics of REY can be clearly identified, and different water mass characteristics can be distinguished. When compared to data reported in other ocean basins and adjacent waters, more differences are found in surface waters due to dust and terrestrial inputs, while the REY concentrations in Indian Ocean are similar to the study region; the REY concentrations in deep water show a positive correlation with the age of water mass, i.e. the concentrations of REY from small to large are Atlantic, Indian Ocean, South Pacific, North Pacific.