Forsterite-Bearing Type B CAI with a Relict Eringaite-Bearing Ultra-Refractory CAI

摘要

Forsterite-bearing Type B (FoB) Ca,Al-richudinclusions (CAIs) are a rare type of coarse-grained igneous CAIsudfound almost exclusively in CV3 chondrites [1–5]. Here weuddescribe the mineralogy, petrography, and oxygen-isotopeudcompositions of a FoB CAI Al-2 from Allende containing a relictuderingaite-bearing ultra-refractory (UR) inclusion. Eringaite is audSc-rich garnet [Ca_3(Sc,Y,Ti)_2Si_3O_(12)] that has been recentlyudidentified in a cluster of UR inclusion fragments within anudamoeboid olivine aggregate in Vigarano [6].