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Wang H, Liu L, Gao Z, Yang L, Naren G, Mao S. Structure and elasticity of CaC 2O 5 suggests carbonate contribution to the seismic anomalies of Earth's mantle. Nat Commun 2024; 15:755. [PMID: 38272879 PMCID: PMC10811330 DOI: 10.1038/s41467-024-44925-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 01/05/2024] [Indexed: 01/27/2024] Open
Abstract
Knowledge of carbonate compounds under high pressure inside Earth is key to understanding the internal structure of the Earth, the deep carbon cycle and major geological events. Here we use first-principles simulations to calculate the structure and elasticity of CaC2O5-minerals with different symmetries under high pressure. Our calculations show that CaC2O5-minerals represent a group of low-density low-seismic-wave velocity mantle minerals. Changes in seismic wave velocity caused by the phase transformation of CaC2O5-Cc to CaC2O5-I[Formula: see text]2d (CaC2O5-C2-l) agree with wave velocity discontinuity at a depth of 660 km in the mantle transition zone. Moreover, when CaC2O5-Fdd2 transforms into CaC2O5-C2 under 70 GPa, its shear wave velocity decreases by 7.4%, and its density increases by 5.8%, which is consistent with the characteristics of large low-shear-velocity provinces (LLSVPs). Furthermore, the shear wave velocity of CaC2O5-I[Formula: see text]2d is very similar to that of cubic Ca-perovskite, which is one of the main constituents of the previously detected LLSVPs. Therefore, we propose that CaC2O5 and its high-pressure polymorphs may be a main component of LLSVPs.
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Affiliation(s)
- Hanyu Wang
- State Key Laboratory of Geological Processes and Mineral Resources, and School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, China
- United Laboratory of High-Pressure Physics and Earthquake Science, Institute of Earthquake Forecasting, China Earthquake Administration, 100036, Beijing, China
| | - Lei Liu
- United Laboratory of High-Pressure Physics and Earthquake Science, Institute of Earthquake Forecasting, China Earthquake Administration, 100036, Beijing, China.
| | - Zihan Gao
- United Laboratory of High-Pressure Physics and Earthquake Science, Institute of Earthquake Forecasting, China Earthquake Administration, 100036, Beijing, China
| | - Longxing Yang
- State Key Laboratory of Geological Processes and Mineral Resources, and School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, China
- United Laboratory of High-Pressure Physics and Earthquake Science, Institute of Earthquake Forecasting, China Earthquake Administration, 100036, Beijing, China
| | - Gerile Naren
- United Laboratory of High-Pressure Physics and Earthquake Science, Institute of Earthquake Forecasting, China Earthquake Administration, 100036, Beijing, China
| | - Shide Mao
- State Key Laboratory of Geological Processes and Mineral Resources, and School of Earth Sciences and Resources, China University of Geosciences, 100083, Beijing, China.
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