Ca-Al-Fe-rich inclusion in the Vigarano CV3 chondrite

Abstract

An anomalous Ca-Al-Fe-rich spherical inclusion (CAFI) was found in the Vigarano CV3 chondrite. The CAFI has an igneous texture and contains large amounts of almost pure and coarse-grained hercynite grains (approximately 56vol%) as well as refractory phases such as grossite and perovskite. However, melilite and Mg-spinel, which are common in ordinary Ca-Al-rich inclusions, are very rare (<1vol%). Another unique characteristic of the CAFI is the presence in its core of dmitryivanovite (CaAl2O4), which was formed by shock metamorphism of a low-pressure form of CaAl2O4 that was originally crystallized from a molten droplet. The fine-grained hercynite and unidentified aluminous phase in the rim of the CAFI may have been produced from grossite during aqueous alteration in the Vigarano parent body. © The Meteoritical Society, 2011.