The kaidum meteorite: an enstatite aggregate with sulfide-oxide inclusions

摘要

An aggregate (approximately 0.5 mm across) examined in the kaidum meteorite is dominated by prismatic crystals of enstatite (Fs_(0.3-2.4), FeO/MnO = 1.9 - 13.6, up to 50 mum long) and contains rare grains of forsterite (Fa_(0.5-0.6, FeO/MnO = 2.4-5.7), which are usually included in enstatie crystals. The interstitial space is filled with calcite a hydrated phase of variable composition. The hydrated phase contains small (< 7 mum) inclusions of sulfide-oxide composition, whose cores consist mostly of Ti and Cr oxides and the rims of Mn and Fe sulfides. The composition and morphology of the enstatite and forsterite suggest that this aggregate is an agglomerate of nebular condensates that was not remelted. The oxide cores of the sulfide-oxide objects are early condensates of the nebula. The sulfide rims were produced during aqueous alterations in the parent body.