Knowledge Management System Of Guangzhou Institute of Geochemistry，CAS
Zou, Zongqi1; Wang, Zaicong2; Wang, Xiao-Jun3; Xu, Yi-Gang1,4 ; Chen, Li -Hui3; Wang, Meiling2; Feng, Lanping2; Li, Ming2; Liu, Yongsheng2
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| Calcium isotopic compositions of eclogite melts and negligible modification during reaction with lithospheric mantle | |
| Source Publication | GEOCHIMICA ET COSMOCHIMICA ACTA
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| ISSN | 0016-7037 |
| 2024-02-15 | |
| Volume | 367Pages:58-71 |
| DOI | 10.1016/j.gca.2023.12.031 |
| Language | 英语 |
| WOS Research Area | Geochemistry & Geophysics |
| Abstract | Subduction-driven recycling of crustal materials plays a substantial role in the generation of geochemical and lithological heterogeneities in the Earth's mantle. Because the distinct compositions and/or mineral-specific equilibrium isotopic fractionation effects are present in eclogitized crustal materials, stable isotopes of major elements that exert significant impacts on geochemical and petrologic properties of the mantle may serve as powerful tracers for linking the geochemical anomaly to lithological heterogeneity within the Earth's interior. Here we present high-precision Ca isotope data, combined with previously reported Mg-Fe isotopes, for a suite of intraplate basalts with a large contribution from recycled crustal material in their mantle sources. The delta Ca-44/40 in these potassic basalts are consistently lower (0.66-0.78 parts per thousand) than those of mid-ocean ridge basalt (MORBs; 0.85 +/- 0.09 parts per thousand), with an average of 0.72 +/- 0.09 parts per thousand. The co-variations of major elements with radiogenic isotopes (e.g., MgO-epsilon(Nd)) reflect the mixing of two distinct endmembers, one of which is the low-MgO primitive melts and the other is the lithospheric mantle. The low-MgO, SiO2-rich primitive melts are characterized by low CaO/Al2O3 (<0.4) and high Dy/Yb (>5). Remarkably, the primitive melts exhibit low delta Ca-44/40 (ca. 0.70 parts per thousand)-delta Mg-26 (ca. -0.60 parts per thousand), and elevated delta Fe-57 (ca. 0.30 parts per thousand) relative to MORBs. These features are consistent with their origin as partial melts of eclogitic crustal materials. During ascending to the surface, these melts reacted with the surrounding lithospheric peridotite. This process resulted in a noticeable shift of the Mg-Fe isotopes towards the typical mantle values but very limited delta Ca-44/40 modification. These results suggest that Ca isotopes largely hold the signature of primary melts and are a promising tracer of eclogite in the mantle source of basalts. We further show that the combined isotopes of Ca-Mg-Fe, which are stoichiometrically incorporated into mantle minerals, offer substantial potential to establish the links between lithological and geochemical heterogeneity in the mantle. |
| Keyword | Ca isotopes Eclogite Melt-lithosphere interaction Lithological heterogeneity |
| WOS ID | WOS:001155847300001 |
| Indexed By | SCI |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.gig.ac.cn/handle/344008/76204 |
| Collection | 同位素地球化学国家重点实验室 |
| Corresponding Author | Wang, Zaicong; Wang, Xiao-Jun |
| Affiliation | 1.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 2.China Univ Geosci, Sch Earth Sci, State Key Lab Geol Proc & Mineral Resources, 388 Lumo Rd, Wuhan 430074, Peoples R China 3.Northwest Univ, Dept Geol, State Key Lab Continental Dynam, Xian 710069, Peoples R China 4.Southern Marine Sci & Engn Guangdong Lab Guangzhou, Guangzhou 511458, Peoples R China |
| Recommended Citation GB/T 7714 | Zou, Zongqi,Wang, Zaicong,Wang, Xiao-Jun,et al. Calcium isotopic compositions of eclogite melts and negligible modification during reaction with lithospheric mantle[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2024,367:58-71. |
| APA | Zou, Zongqi.,Wang, Zaicong.,Wang, Xiao-Jun.,Xu, Yi-Gang.,Chen, Li -Hui.,...&Liu, Yongsheng.(2024).Calcium isotopic compositions of eclogite melts and negligible modification during reaction with lithospheric mantle.GEOCHIMICA ET COSMOCHIMICA ACTA,367,58-71. |
| MLA | Zou, Zongqi,et al."Calcium isotopic compositions of eclogite melts and negligible modification during reaction with lithospheric mantle".GEOCHIMICA ET COSMOCHIMICA ACTA 367(2024):58-71. |
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