Aqueous alteration of enstatite chondrite clasts in Kaidun meteorite

Abstract

We studied aqueously altered EH and EL in Kaidun. Two clasts show alteration of Fe-Ni metal and plagioclase and elongated Ca carbonate is often present at the boundary between altered E chondrite and surrounding C chondrite. These features are similar to the E chondrite clast in Kaidun #40.7.1, suggesting they experienced same alteration. We have carried out hydrothermal experiments with EL5 in HCl, H₂O, NaCl and NaOH. In HCl, Fe-Ni metal and troilite disappeared, and therefore the aqueously altered conditions of E chondrites in Kaidun was not under an acidic condition.