Metal accumulation rates in northwest Atlantic pelagic sediments
Metal accumulation rates in northwest Atlantic pelagic sediments
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DOI：
10.1016/0016-7037(84)90376-4
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发表时间：
1984-10
影响因子：
5
通讯作者：
J. Thomson;M. Carpenter;S. Colley;T. Wilson;H. Elderfield;H. Kennedy
中科院分区：
文献类型：
--
作者：
J. Thomson;M. Carpenter;S. Colley;T. Wilson;H. Elderfield;H. Kennedy
对纳尔斯深海平原的岩心进行了230 Th、87 Sr、86 Sr和24种金属的测量。沉积物的特征是缓慢沉积（0.3 ~ 0.7 g/cm 210.3年）的远洋红粘土和快速沉积的灰色粘土，由浊度流运输。尽管红粘土的颜色不同，Mn、Fe、Cu、Co、Ni、Zn、V富集，稀土富集程度较低，但Sr同位素证据表明，红粘土具有相同的陆源成因。红粘土中的金属过量归因于水柱中金属的去除，与灰粘土的比较使金属的自生通量得以估计。Mn、Fe的通量为20 ~ 50 μmol/cm 2103yr， Cu、Co、Ni、Zn、V、Sr、Ce的通量为0.1 ~ 0.4 μmol/cm 2103yr， La、Nd的通量为10 ~ 20 μmol/cm 2103yr， Sm、Eu、Gd、Dy、Er、Yb的通量为0.5 ~ 3 nmol/cm 2103yr。Y、Nb、Cr、Zr、Rb、U和Th的自生通量不可分辨。平原上的通量似乎几乎是恒定的，但与其他地区的比较表明，它们在海洋盆地之间和在海洋盆地内部变化很大。控制自生通量的主要因素是元素的地球化学丰度，但过渡元素和稀土系列内部的分异可以从元素间比较和大西洋和太平洋红粘土之间与元素海洋反应性相对应的通量差异中识别出来。
Abstract Measurements of 230 Th, 87 Sr 86 Sr and twenty-four metals were made on cores from the Nares Abyssal Plain. The sediment is characterized by slowly-accumulating (0.3–0.7 g/cm 2 10 3 yr) pelagic red clays and rapidly deposited grey clays transported by turbidity currents. Despite their colour differences and the enrichment of Mn, Fe, Cu, Co, Ni, Zn, V and, to a lesser degree, the rare earths in the red clays, Sr isotope evidence demonstrates that the clays have the same terrigenous origin. The excesses of metals in the red clays have been attributed to metal removal from the water column and a comparison with the grey clays has enabled the authigenic fluxes of metals to be estimated. The fluxes obtained are in the ranges 20–50 μmol/cm 2 10 3 yr for Mn and Fe, 0.1–0.4 μmol/cm 2 10 3 yr for Cu, Co, Ni, Zn, V, Sr and Ce, 10–20 nmol/cm 2 10 3 yr for La and Nd, and 0.5-3 nmol/cm 2 10 3 yr for Sm, Eu, Gd, Dy, Er and Yb. Authigenic fluxes of Y, Nb, Cr, Zr, Rb, U and Th were not resolvable. Fluxes appear to be near constant on the Plain but comparison with other areas shows that they are quite variable both between and within ocean basins. The chief factor controlling authigenic fluxes is the geochemical abundances of the elements but fractionation within both the transition element and rare earth series can be recognized from inter-element comparisons and from differences in fluxes between Atlantic and Pacific red clays corresponding to the oceanic reactivities of the elements.