Stable calcium isotopic compositions of Hawaiian shield lavas: Evidence for recycling of ancient marine carbonates into the mantle
Stable calcium isotopic compositions of Hawaiian shield lavas: Evidence for recycling of ancient marine carbonates into the mantle
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DOI：
10.1016/j.gca.2011.06.010
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发表时间：
2011-09-01
影响因子：
5
通讯作者：
Jacobsen, Stein B.
中科院分区：
文献类型：
--
作者：
Huang, Shichun;Farkas, Juraj;Jacobsen, Stein B.
我们报告了夏威夷地盾阶段拉斑玄武岩的高精度Ca-44/Ca-40测量结果（2 σ m < 0.06 ppm）。我们的数据显示，它们的Ca-44/Ca-40的变化类似于千分之0.3，这相当于在全球碳酸盐中观察到的Ca-44/Ca-40变化的20%。Ca-44/Ca-40的变化与Sr/Nb和Sr-87/Sr-86相关，这一模式最好的解释是在夏威夷地幔柱中加入4%的古碳酸盐。质量平衡计算表明，高达40%的Ca预算和65%的Sr预算在一些夏威夷（Makapuu阶段Koolau）熔岩来自回收的碳酸盐。我们的发现表明，第一次与钙同位素的应用，古老的回收碳酸盐是地幔柱的重要组成部分，饲料一些最大的陆地火山。因此，碳酸盐向地幔的再循环是全球Ca和C循环的重要组成部分。(C)2011爱思唯尔有限公司版权所有。
We report high-precision Ca-44/Ca-40 measurements (2 sigma m < 0.06 parts per thousand) of Hawaiian shield stage tholeiites. Our data reveal similar to 0.3 parts per thousand variation in their Ca-44/Ca-40, which comprises similar to 20% of the Ca-44/Ca-40 variation observed in global carbonates. The Ca-44/Ca-40 variation is correlated with Sr/Nb and Sr-87/Sr-86, and this pattern is best explained by adding up to 4% ancient carbonate into the Hawaiian plume. Mass-balance calculations show that up to 40% of the Ca budget and 65% of the Sr budget in some Hawaiian (Makapuu-stage Koolau) lavas are derived from recycled carbonates. Our finding demonstrates, for the first time with the application of Ca isotopes, that ancient recycled carbonates are important components of mantle plumes which feed some of the largest terrestrial volcanoes. Thus, recycling of carbonates into the mantle is an essential part of the global Ca and C cycles. (C) 2011 Elsevier Ltd. All rights reserved.