| Abstract | This study analyzed three eucrites (LEW 88010, Bouvante, and NWA 483), reassessed major element data from Mayne et al. (2009), and conducted a literature review of metasomatic features to determine if there were any trends among metasomatized eucrites that could further the understanding of metasomatism on Vesta. Twenty-one eucrites were identified as having one or more of the following features that could be attributed to metasomatism: Fe-enrichments in pyroxene near cracks, fayalite veins in the cracks of pyroxene, Fe-enriched and Al-depleted pyroxene grains, pyroxene that has been broken down into silica and troilite, and accessory minerals associated with metasomatism. There are trends in the features, both with respect to type of eucrite and geochemical grouping. There were none of the above-mentioned features of metasomatism in cumulate eucrites, indicating that crustal depth is a strong control on metasomatism. Fayalite veins are found most commonly in polymict eucrites and eucrite clasts of howardites and the breakdown of pyroxene to silica and troilite is more common in Stannern-trend eucrites. The diversity of features suggests multiple mechanisms for metasomatism, such as multiple metasomatizing fluids, because one single process could not cause all of the features and associated trends. |
