Unique (Al,Cu)-alloys discovered in a micrometeorite from Southern Italy

Abstract We report the discovery of a (Al,Cu)-bearing micrometeorite recovered at the top of Mt. Gariglione (Italy). The micrometeorite exhibits a highly vesicular scoriaceous structure characterized by broadly chondritic silicate-dominated composition (S-type) with relict phenocrystals of forsterit...

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Bibliographic Details
Main Authors: Giovanna Agrosì, Paola Manzari, Daniela Mele, Gioacchino Tempesta, Floriana Rizzo, Tiziano Catelani, Guangming Cheng, Nan Yao, Johan Villeneuve, Luca Bindi
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:Communications Earth & Environment
Online Access:https://doi.org/10.1038/s43247-025-02245-w
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Summary:Abstract We report the discovery of a (Al,Cu)-bearing micrometeorite recovered at the top of Mt. Gariglione (Italy). The micrometeorite exhibits a highly vesicular scoriaceous structure characterized by broadly chondritic silicate-dominated composition (S-type) with relict phenocrystals of forsteritic olivine dispersed in a Ca-rich silicate glass with pyroxene composition, droplets of FeNi metal, oxides and sporadic Ni-rich sulphides embedded in a magnetite rim. The oxygen 3-isotope analyses give values close to the slope ~1 CCAM. A reduced assemblage of (Al,Cu)-alloys partially fills the open voids of the micrometeorite and shows variable compositions: from almost pure Cu up to Al-dominated phases with a predominance of khatyrkite, stolperite and unnamed Cu3Al2. Locally, small grains (about 1-2 µm in size) embedded in stolperite show a Fe-Si enrichment and are characterized by a long-range ordering resembling a quasicrystalline structure. This finding represents a unique natural quasicrystal approximant with composition Al52Cu31Fe10Si7.
ISSN:2662-4435