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Wang W, Walter MJ, Brodholt JP, Huang S, Petaev MI. Chalcogen isotopes reveal limited volatile contribution from late veneer to Earth. SCIENCE ADVANCES 2023; 9:eadh0670. [PMID: 38055829 DOI: 10.1126/sciadv.adh0670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 11/07/2023] [Indexed: 12/08/2023]
Abstract
The origin of Earth's volatile elements is highly debated. Comparing the chalcogen isotope ratios in the bulk silicate Earth (BSE) to those of its possible building blocks, chondritic meteorites, allows constraints on the origin of Earth's volatiles; however, these comparisons are complicated by potential isotopic fractionation during protoplanetary differentiation, which largely remains poorly understood. Using first-principles calculations, we find that core-mantle differentiation does not notably fractionate selenium and tellurium isotopes, while equilibrium evaporation from early planetesimals would enrich selenium and tellurium in heavy isotopes in the BSE. The sulfur, selenium, and tellurium isotopic signatures of the BSE reveal that protoplanetary differentiation plays a key role in establishing most of Earth's volatile elements, and a late veneer does not substantially contribute to the BSE's volatile inventory.
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Affiliation(s)
- Wenzhong Wang
- Deep Space Exploration Lab/School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence in Comparative Planetology, University of Science and Technology of China, Hefei, Anhui 230026, China
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
- Department of Earth Sciences, University College London, London WC1E 6BT, UK
| | - Michael J Walter
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
| | - John P Brodholt
- Department of Earth Sciences, University College London, London WC1E 6BT, UK
- Centre of Planetary Habitability, University of Oslo, Oslo, Norway
| | - Shichun Huang
- Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN 37996, USA
| | - Michail I Petaev
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
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Liu Y, Chou IM, Chen J, Wu N, Li W, Bagas L, Ren M, Liu Z, Mei S, Wang L. Oldhamite: a new link in upper mantle for C-O-S-Ca cycles and an indicator for planetary habitability. Natl Sci Rev 2023; 10:nwad159. [PMID: 37671325 PMCID: PMC10476894 DOI: 10.1093/nsr/nwad159] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 05/17/2023] [Accepted: 05/24/2023] [Indexed: 09/07/2023] Open
Abstract
In the solar system, oldhamite (CaS) is generally considered to be formed by the condensation of solar nebula gas. Enstatite chondrites, one of the most important repositories of oldhamite, are believed to be representative of the material that formed Earth. Thus, the formation mechanism and the evolution process of oldhamite are of great significance to the deep understanding of the solar nebula, meteorites, the origin of Earth, and the C-O-S-Ca cycles of Earth. Until now, oldhamite has not been reported to occur in mantle rock. However, here we show the formation of oldhamite through the reaction between sulfide-bearing orthopyroxenite and molten CaCO3 at 1.5 GPa/1510 K, 0.5 GPa/1320 K, and 0.3 GPa/1273 K. Importantly, this reaction occurs at oxygen fugacities within the range of upper-mantle conditions, six orders of magnitude higher than that of the solar nebula mechanism. Oldhamite is easily oxidized to CaSO4 or hydrolysed to produce calcium hydroxide. Low oxygen fugacity of magma, extremely low oxygen content of the atmosphere, and the lack of a large amount of liquid water on the celestial body's surface are necessary for the widespread existence of oldhamite on the surface of a celestial body otherwise, anhydrite or gypsum will exist in large quantities. Oldhamites may exist in the upper mantle beneath mid-ocean ridges. Additionally, oldhamites may have been a contributing factor to the early Earth's atmospheric hypoxia environment, and the transient existence of oldhamites during the interaction between reducing sulfur-bearing magma and carbonate could have had an impact on the changes in atmospheric composition during the Permian-Triassic Boundary.
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Affiliation(s)
- Yuegao Liu
- CAS Key Laboratory for Experimental Study under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
- Hainan Deep-Sea Technology Innovation Center, Sanya 572000, China
| | - I-Ming Chou
- CAS Key Laboratory for Experimental Study under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
| | - Jiangzhi Chen
- CAS Key Laboratory for Experimental Study under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
- Hainan Deep-Sea Technology Innovation Center, Sanya 572000, China
| | - Nanping Wu
- CAS Key Laboratory for Experimental Study under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
| | - Wenyuan Li
- Xi’an Center of Geological Survey, China Geological Survey, Xi’an 710054, China
| | - Leon Bagas
- Xi’an Center of Geological Survey, China Geological Survey, Xi’an 710054, China
| | - Minghua Ren
- Department of Geoscience, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA
| | - Zairong Liu
- CAS Key Laboratory for Experimental Study under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
| | - Shenghua Mei
- CAS Key Laboratory for Experimental Study under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China
- Hainan Deep-Sea Technology Innovation Center, Sanya 572000, China
| | - Liping Wang
- Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China
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