The first Al-Cu-alloy-bearing unmelted micrometeorite suggests contributions from the disrupted ureilite protoplanet
Abstract
We report the discovery of Al-Cu-alloys within a coarse-grained micrometeorite from the Congo. Oxygen isotope ratios of the sample are consistent with a CV3 source, similar to the Khatyrka meteorite. The petrology of the micrometeorite is also similar to Khatyrka and testifies to the disequilibrium impact mixing between the CV3 parent body and a differentiated body, which was the source of the Al-Cu-alloys. The oxygen isotope composition, however, suggests either limited mixing with projectile silicates or a differentiated projectile with oxygen isotopes close to the CCAM. The most plausible origin of the Al-Cu-alloys is the desilication of an aluminous igneous protolith by hydrothermal activity under highly reduced conditions. We argue that the ureilite parent body is the most likely source for the projectile owing to its silicic magmatism, late-stage reduction and similar oxygen isotope ratios. Al-Cu-alloys can, thus, be found on the disrupted remnants of such protoplanets.
Copyright and License
© 2025 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Acknowledgement
WiscSIMS is partly supported by NSF (EAR2004618). This study was conducted within the Space It Up project funded by the Italian Space Agency, ASI, and the Ministry of University and Research, MUR, under contract n. 2024–5-E.0-CUP n. I53D24000060005.
Contributions
Matthew J. Genge: Writing – review & editing, Writing – original draft, Investigation, Conceptualization. Matthias Van Ginneken: Writing – review & editing. Chi Ma: Writing – review & editing, Methodology, Formal analysis. Martin D. Suttle: Writing – review & editing. Natasha Almeida: Writing – review & editing, Formal analysis. Noriko T. Kita: Writing – review & editing, Methodology, Investigation, Formal analysis. Mingming Zhang: Writing – review & editing. Luca Bindi: Writing – review & editing, Project administration, Methodology, Investigation, Funding acquisition, Conceptualization.
Conflict of Interest
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Luca Bindi reports financial support was provided by Italian Space Agency. Noriko Kita reports financial support was provided by National Science Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Data Availability
No data was used for the research described in the article.
Supplemental Material
Supplementary materials (DOCX)
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Additional details
- National Science Foundation
- EAR-2004618
- Agenzia Spaziale Italiana
- Ministero dell'Istruzione, dell'Università e della Ricerca
- I53D24000060005
- Accepted
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2025-02-17Accepted
- Available
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2025-02-22Available online
- Available
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2025-02-22Version of Record
- Caltech groups
- Division of Geological and Planetary Sciences (GPS)
- Publication Status
- Published