Variety of silica minerals in Yamato-75011 eucrite

Abstract

We analyzed silica polymorphs in two basaltic clasts and matrix of Y-75011 (polymict eucrite). Many kinds of silica combinations have been found such as monoclinic and orthorhombic tridymites. We consider that such variety of silica minerals indicates different cooling processes before brecciation. We also found monoclinic tridymite in the matrix with a corona-like texture, which is nearly identical to ones in Pasamonte (polymict eucrite). This suggests that they came from the same parent body.