The chromium isotopic composition of seawater and marine carbonates
The chromium isotopic composition of seawater and marine carbonates
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DOI：
10.1016/j.epsl.2013.09.001
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发表时间：
2013-11-15
影响因子：
5.3
通讯作者：
Fairchild, I. J.
中科院分区：
文献类型：
--
作者：
Bonnand, P.;James, R. H.;Fairchild, I. J.
铬同位素在氧化还原反应过程中发生分馏，有可能提供地质历史中海洋氧化水平变化的记录。然而，铬是海水中的一种微量金属，其低浓度使同位素测量具有挑战性。在这里，我们报告的第一个确定三角洲Cr-53海水从公海（阿根廷盆地）和沿海（南安普顿水）设置，使用双穗技术。来自南安普顿水的海水中的总铬浓度为1.85 nM，而阿根廷盆地样品的铬含量为5.8-6.6 nM。阿根廷盆地海水的Cr-53三角洲值在中层和深层沃茨中为千分之0.491-0.556，在表层沃茨中为千分之0.412 - 0.664（
Chromium isotopes are fractionated during redox reactions and have the potential to provide a record of changes in the oxygenation levels of the oceans in the geological past. However, Cr is a trace metal in seawater and its low concentrations make isotopic measurements challenging. Here we report the first determinations of delta Cr-53 for seawater from open ocean (Argentine Basin) and coastal (Southampton Water) settings, using a double-spike technique. The total chromium concentration in seawater from Southampton Water is 1.85 nM, whereas the Cr content of Argentine Basin samples is 5.8-6.6 nM. The delta Cr-53 value of seawater from the Argentine Basin is 0.491-0.556 parts per thousand in intermediate and deep waters, and varies between 0.412 and 0.664 parts per thousand in surface waters (