The geochemical behavior and isotopic composition of Hg in a mid-Pleistocene western Mediterranean sapropel
The geochemical behavior and isotopic composition of Hg in a mid-Pleistocene western Mediterranean sapropel
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DOI：
10.1016/j.gca.2008.12.012
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发表时间：
2009-03-15
影响因子：
5
通讯作者：
Meyers, Philip A.
中科院分区：
文献类型：
--
作者：
Gehrke, Gretchen E.;Blum, Joel D.;Meyers, Philip A.
在中更新世地中海腐泥层序中，对汞 (Hg) 和其他痕量金属（Ni、Cu、Zn、Mo、Ba、Re、U）的浓度以及 Hg 同位素组成进行了显着的氧化还原和生产力转变。在富含有机物层中观察到了特征性痕量金属富集，富含有机物腐泥层的汞浓度范围为 314 至 488 ng/g（平均值 = 385），与贫有机物背景沉积物（范围为 39 至 94 ng/g Hg（平均值 = 66））相比，汞的平均富集度为 5.9 倍。海水浓度和腐泥中痕量金属积累的比较表明，有机物定量地将汞输送到海底。从水柱中几乎完全清除汞使得腐泥汞同位素组成代表了中更新世地中海海水。腐泥的平均 delta(202)Hg 值为 -0.91 ppm +/- 0.15 ppm。 (n = 5, 1 SD) 和 Delta(199)Hg 值为 0.11 千分之 +/- 0.03 千分之一 (n = 5, 1 SD)。背景沉积物的平均 8202 Hg 为 -0.76 ppm +/- 0.16 ppm (n = 5, 1 SD)，Delta(199)Hg 为 0.05 ppm +/- 0.01 ppm。 (n = 5, 1 SD)，与腐泥值无法区分。我们认为腐泥同位素组成最能代表中更新世第勒尼安海。 (C) 2008 Elsevier Ltd. 保留所有权利。
The concentrations of mercury (Hg) and other trace metals (Ni, Cu, Zn, Mo, Ba, Re, U) and the Hg isotopic composition were examined across a dramatic redox and productivity transition in a mid-Pleistocene Mediterranean Sea sapropel sequence. Characteristic trace metal enrichment in organic-rich layers was observed, with organic-rich sapropel layers ranging in Hg concentration from 314 to 488 ng/g (avg = 385), with an average enrichment in Hg by a factor of 5.9 compared to organic-poor background sediments, which range from 39 to 94 ng/g Hg (avg = 66). Comparison of seawater concentrations and sapropel accumulations of trace metals suggests that organic matter quantitatively delivers Hg to the seafloor. Near complete scavenging of Hg from the water column renders the sapropel Hg isotopic composition representative of mid-Pleistocene Mediterranean seawater. Sapropels have an average delta(202)Hg value of -0.91 parts per thousand +/- 0.15 parts per thousand. (n = 5, 1 SD) and Delta(199)Hg value of 0.11 parts per thousand +/- 0.03 parts per thousand (n = 5, 1 SD). Background sediments have an average 8202 Hg of -0.76 parts per thousand +/- 0.16 parts per thousand (n = 5, 1 SD) and Delta(199)Hg of 0.05 parts per thousand +/- 0.01 parts per thousand. (n = 5, 1 SD), which is indistinguishable from the sapropel values. We suggest that the sapropel isotopic composition is most representative of the mid-Pleistocene Tyrrhenian Sea. (C) 2008 Elsevier Ltd. All rights reserved.