The first discovery of a shocked, metasomatised CV3 chondrule‐fragment in a (Al,Cu)‐bearing micrometeorite

Abstract We report the discovery of the second (Al,Cu)‐alloy–bearing micrometeorite, FB‐A2, recovered from Mount Gariglione (southern Italy), representing the sixth such occurrence worldwide. Although chondritic in nature, FB‐A2 differs markedly from previously described microspherules. It is a scoriaceous micrometeorite dominated by silicates and contains a relict clast composed of Mg‐rich olivine and pyroxene phenocrysts set in a Fe‐rich silicate matrix. The particle rim hosts fine aggregates of phosphates, magnetite, Ni‐bearing magnetite, and sulfides, whereas the interior contains nepheline crystals. A 120 μm (Al,Cu)‐alloy grain occurs at one corner of the particle. The porphyritic texture of the clast indicates a chondrule fragment—the first identified in an (Al,Cu)‐bearing micrometeorite—while polyhedral sub‐grain boundaries and metal–sulfide veins record shock metamorphism. Iron‐rich alteration of relict silicates is consistent with high‐temperature (<560 °C) metasomatism typical of CV3 chondrites and is supported by oxygen isotope compositions close to the Carbonaceous Chondrite Anhydrous Mineral Line. Brecciation of chondrule olivine suggests impact‐induced fluid pressure excursions during early Solar System metasomatism, whereas impact melt enveloping elongate olivines indicates a later impact that introduced the (Al,Cu)‐alloys. Overall, the texture, mineralogy, and isotopic composition of FB‐A2 provide the most detailed constraints yet on the origin of (Al,Cu)‐bearing micrometeorites and confirm a genetic link to the Khatyrka meteorite.