Wereport 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 closetotheslope~1CCAM.Areducedassemblageof(Al,Cu)-alloyspartiallyfillstheopenvoidsofthe micrometeorite and shows variable compositions: from almost pure Cu up to Al-dominated phases withapredominanceofkhatyrkite,stolperiteandunnamedCu3Al2.Locally,smallgrains(about1-2 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.
Unique (Al,Cu)-alloys discovered in a micrometeorite from Southern Italy
Agrosi, Giovanna
Writing – Original Draft Preparation
;Mele, DanielaMembro del Collaboration Group
;Tempesta, GioacchinoMembro del Collaboration Group
;Rizzo, FlorianaMembro del Collaboration Group
;
2025-01-01
Abstract
Wereport 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 closetotheslope~1CCAM.Areducedassemblageof(Al,Cu)-alloyspartiallyfillstheopenvoidsofthe micrometeorite and shows variable compositions: from almost pure Cu up to Al-dominated phases withapredominanceofkhatyrkite,stolperiteandunnamedCu3Al2.Locally,smallgrains(about1-2 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
