Petrologic study of SJ101, a new forsterite-bearing CAI from the Allende CV3 chondrite

The Group II REE pattern, slightly negative δ29Si and δ25Mg values, and nearly solar ratios of the major elements in the bulk SJ101 suggest that its precursors, proto-CAIs and Fo-rich rims, could have formed by a non-equilibrium condensation in a closed system of solar composition somewhat depleted in a super-refractory evaporation residue. The proposed formation scenario of SJ101 invokes a non-steady cooling and condensation of the nebular gas interrupted by at least two distinct melting episodes required to account for the igneous textures of the Mel-An-Cpx-rich cores (proto-CAIs) and the Fo-Cpx lithology.