Ca isotope systematics of carbonatites: Insights into carbonatite source and evolution
Ca isotope systematics of carbonatites: Insights into carbonatite source and evolution
复制标题
碳酸岩的 Ca 同位素系统学：深入了解碳酸岩的来源和演化
DOI：
10.7185/geochemlet.2107
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发表时间：
2021-02-17
影响因子：
4.9
通讯作者：
Henderson, G. M.
中科院分区：
文献类型：
--
作者：
Sun, J.;Zhu, X-K;Henderson, G. M.
土井：10.7185/geochemlet.2107碳酸盐岩是一种罕见的富含碳酸盐的火成岩，已知其来源于地幔，这为地幔至地壳的碳转移提供了见解。为了进一步确定碳酸岩的Ca同位素组成，研究其演化过程中Ca同位素的行为，并确定其源区是否存在再循环碳酸盐岩，我们采用精细分析方法对全球47个碳酸岩和伴生硅酸盐岩的δ44/42 Ca进行了研究。我们的研究结果表明，原生碳酸岩和伴生硅酸盐岩石的Ca同位素组成相当均匀，与玄武岩的δ44/42 Ca值相当，而非原生碳酸岩显示出可检测的δ44/42 Ca变化，与δ 13 C值相关。研究结果表明，Ca同位素在碳酸盐岩演化的晚期阶段具有明显的断裂特征，是研究碳酸盐岩演化的有效工具。这一发现还意味着碳酸盐岩来源于地幔源，而不需要再循环碳酸盐的参与。收到2020年9月8日|2021年1月8日接受|发布17二月2021
doi: 10.7185/geochemlet.2107 Carbonatite, an unusual carbonate-rich igneous rock, is known to be sourced from themantlewhich provides insights intomantle-to-crust carbon transfer. To constrain further the Ca isotopic composition of carbonatites, investigate the behaviour of Ca isotopes during their evolution, and constrain whether recycled carbonates are involved in their source regions, we report δ44/42Ca for 47 worldwide carbonatite and associated silicate rocks using a refined analytical protocol. Our results show that primary carbonatite and associated silicate rocks are rather homogeneous in Ca isotope compositions that are comparable to δ44/42Ca values of basalts, while nonprimary carbonatites show detectable δ44/42Ca variations that are correlated to δ13C values. Our finding suggests that Ca isotopes fractionate during late stages of carbonatite evolution, making it a useful tool in the study of carbonatite evolution. The finding also implies that carbonatite is sourced from a mantle source without requiring the involvement of recycled carbonates. Received 8 September 2020 | Accepted 8 January 2021 | Published 17 February 2021