Oxygen isotope identity of the Earth and Moon with implications for the formation of the Moon and source of volatiles

• 成果类型: Article
• 署名作者: Fischer, Meike; Peters, Stefan T. M.; Herwartz, Daniel; Hartogh, Paul; Di Rocco, Tommaso; Pack, Andreas
• 署名单位: University of Gottingen; Max Planck Society; Thermo Fisher Scientific; University of Cologne; Ruhr University Bochum
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12748
• DOI: 10.1073/pnas.2321070121
• 发表日期: 2024-12-24
• 关键词: tungsten isotopes; giant impact; origin; water; terrestrial; homogeneity; accretion; basalts; ratios; SYSTEM

摘要

The Moon formed 4.5 Ga ago through a collision between proto-Earth and a planetesimal known as Theia. The compositional similarity of Earth and Moon puts tight limits on the isotopic contrast between Theia and proto- Earth, or it requires intense homogenization of Theia and proto-Earth material during and in the aftermath of the Moon- forming impact, or a combination of both. We conducted precise measurements of oxygen isotope ratios of lunar and terrestrial rocks. The absence of an isotopic difference between the Moon and Earth on the sub-ppm level, as well as the absence of isotope heterogeneity in Earth's upper mantle and the Moon, is discussed in relation to published Moon formation scenarios and the collisional erosion of Theia's silicate mantles prior to colliding with proto- Earth. The data provide valuable insights into the origin of volatiles in the Earth and Moon as they suggest that the water on the Earth may not have been delivered by the late veneer. The study also highlights the scientific value of samples returned by space missions, when compared to analyses of meteorite material, which may have interacted with terrestrial water.