Geochemical Diversity in the Mantle
Geochemical Diversity in the Mantle
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DOI：
10.1002/9781119528609.ch5
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发表时间：
2021-07
期刊：
影响因子：
--
通讯作者：
T. Hanyu;Li‐Hui Chen
中科院分区：
文献类型：
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作者：
T. Hanyu;Li‐Hui Chen
洋中脊玄武岩（MORB）和洋岛玄武岩（OIB）的研究已经分别揭示了浅地幔和深地幔的异质性。在OIB中观察到的放射性同位素和微量元素组成的巨大变化被认为是来自古老的回收俯冲物质，这些物质曾经存在于地球表面附近，现在储存在地幔深处。玄武岩中的主要元素，橄榄石斑晶中的次要元素，以及传统和非传统的稳定同位素的最新应用提供了机会，不仅确定俯冲的材料，但也促进了更好地理解的过程中发生的岩石圈板片俯冲和地幔上涌的分化和反应。碳酸盐岩在不同地幔组分的形成中起着重要作用，这一点最近得到了人们的认可。这些碳酸盐熔体，来自俯冲碳酸盐物质，交代周围的橄榄岩地幔，形成化学富集的辉石岩和肥沃的橄榄岩。最近的研究表明，其他挥发性元素，如水和卤素以及碳，在地球表面和地幔深处之间进行交换。此外，物质的交换似乎影响了地球表面和地幔中化学成分和氧化还原状态的相互变化。
Studies of mid‐ocean ridge basalts (MORBs) and ocean island basalts (OIBs) have unraveled the heterogeneous nature of the shallow and deep mantle, respectively. Large variations in radiogenic isotopes and trace element compositions observed in OIBs are thought to originate from ancient recycled subducted materials that once existed near the Earth's surface and that are now stored in the deep mantle. Recent applications of major elements in basalts, minor elements in olivine phenocrysts, and traditional and nontraditional stable isotopes provide opportunities to not only identify subducted materials but also promote an improved understanding of the processes of differentiation and reaction that occur during lithospheric slab subduction and mantle upwelling. Recycled carbonates have recently gained recognition as playing a role in the formation of distinct mantle components. These carbonatitic melts, originating from subducted carbonated materials, metasomatize the surrounding peridotitic mantle and form chemically enriched pyroxenite and fertile peridotite. Recent studies have shown that other volatile elements, such as water and halogens together with carbon, exchange between the Earth's surface and the deep mantle. Moreover, the exchange of materials appears to have influenced mutual changes in chemical compositions and the redox state at the Earth's surface and in the mantle.