"S.Singletary" wrote: > Have a look at:
> Hsu, W., et al., 2000, High Time resolution by use of the 26Al chronometer > in the multistage formation of a CAI (Earth and Planetary Science Letters, > 182, p.15-29). > They are indeed complicated little beasties. I agree re: those "little beasties" :-) Krot et al. describe accretionary rims around several CAIs in the Allende CV3 chondrite. The accretionary rims in Allende are multi- layered and these layers differ from one another in - texture, - mineralogy and - mineral chemistry. The different layers (innermost to outermost) consist of: 1) Either pyroxene needles + olivine + clumps of hedenbergite and andradite (IA) or 2) Olivine "doughnuts" (IB) (i.e., crystals with central cavities). 3) II and III contain olivine plates and laths. 4) The final layer (IV) separating accretionary rims from the Allende matrix occurs as clumps of andradite + hedenbergite surrounded by salitic pyroxene needles. => Nepheline and Fe,Ni-sulfides are common constituents in all layers. Reference: KROT A.N. et al. (2001) Forsterite-rich accretionary rims around calcium-aluminum-rich inclusions from the reduced CV3 chondrite Efremovka (MAPS 36-5, 2001, pp. 611-628). Cheers, Bernd ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list