^1,2Matthew J. Genge, ³Matthias Van Ginneken, ⁴Chi Ma, ⁵Martin D. Suttle, ^1,2Natasha Almeida, ⁶Noriko T. Kita, ⁶Mingming Zhang, ⁷Luca Bindi
Earth and Planetary Science Letters 656, 119276 Open Access Link to Articel [https://doi.org/10.1016/j.epsl.2025.119276]
¹Department of Earth Science and Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
²Planetary Materials Group, Natural History Museum, London, SW7 5BD, UK
³Department of Physics and Astronomy, Centre for Astrophysics and Planetary Science, University of Kent, Canterbury, Kent, CT2 7NH, UK
⁴Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
⁵School of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
⁶Department of Geoscience, University of Wisconsin-Madison, 1215W. Dayton St., Madison, WI, 53706, USA
⁷Dipartimento di Scienze della Terra, Università di Firenze, Via La Pira 4, I, 50121, Florence, Italy
Copyright Elsevier

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.