Calcium isotopic variability in hotspot lavas controlled by partial melting and source lithological heterogeneity

Wang, Xiao-Jun; Chen, Li-Hui; Hanyu, Takeshi; Zhou, Zhong-Biao; Liu, Jian-Qiang; Zeng, Gang; Zou, Zong-Qi; Bai, Jiang-Hao

doi:10.1016/j.chemgeo.2023.121857

Cited by 6 publications

(1 citation statement)

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“…The geochemical variabilities in metasomatized mantle induced by incorporation of metasomatic agents and/or isotopic fractionation due to specific minerals thus contain a wealth of information about the evolution of the Earth. For example, stable Ca‐Fe isotopes are effective tools for identifying the lithological heterogeneities that arise from the operation of plate tectonics (e.g., Eriksen & Jacobsen, 2022; Nebel et al., 2019; Soderman et al., 2022; Wang et al., 2024; Williams & Bizimis, 2014; Zou, Wang, Wang, et al., 2024). Therefore, understanding the behavior of chemical proxies during mantle metasomatism is essential for using them to decipher the evolution and modification of the Earth's interior.…”

Section: Introductionmentioning

confidence: 99%

Stable Zirconium Isotopic Compositions of the Metasomatized Mantle

Zou,

Xu,

Wang

et al. 2024

JGR Solid Earth

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Mantle metasomatism, which affects the geochemical and lithological properties of the Earth, is crucial to the evolution and modification of the Earth's interior. Variations in chemical proxy of metasomatism, including high‐field strength elements (HFSE, e.g., Zr‐Ti isotopes and isovalent Zr‐Hf), have been commonly utilized as a tool to unravel the processes associated with the evolution of the Earth. However, the impact of mantle metasomatism by diverse agents on the Zr isotopic compositions of metasomatized mantle remains poorly understood. Here we carried out high‐precision double‐spike δ94/90Zr measurements for a suite of basalts, which were derived from the mantle sources metasomatized by typical metasomatic agents of fluid, silicate melt and carbonate melt originating from the deep mantle or recycled crustal materials. Mantle metasomatism results in lithological diversities within the mantle, ranging from hybridized peridotites to pyroxenite/eclogite and carbonated eclogite, which can significantly fractionate the isovalent HFSEs. However, our data show that these basalts have primitive mantle‐like δ94ZrNIST values (−0.033–0.043 ‰), regardless of their superchondritic Zr/Hf. The primitive mantle‐like δ94ZrNIST, irrelevant to any proxy of metasomatism (e.g., Sr‐Nd isotopes, Zr/Hf and La/Sm), indicate that mantle metasomatism and subsequence melting produce no measurable Zr isotopic variations in metasomatized mantle‐derived basalts. The δ94ZrNIST of basalts thus can be representative of the mean metasomatized mantle compositions. Combined with previously reported komatiites and oceanic basalts, we show that the Earth's mantle displays consistent δ94ZrNIST (−0.013 ± 0.053 ‰), even if it has a secular dynamic evolution with the interaction between Earth's exterior and interior.

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