Pure CaO, MgO (Periclase), TiO2 (Rutile), and Al2O3 (Corundum) in Ca,Al-rich Inclusions from Carbonaceous Chondrites
Transmission electron microscopy (TEM) studies were performed on four Ca,Al-rich inclusions (two Type A, one Type B, and a spinel-perovskite spherule) from the carbonaceous chondrites Allende (CV3), Acfer 082 (CV3), Acfer 086 (CV3), and Acfer 094 (unique). Two Type A and one Type B inclusion contain the pure oxide phases rutile (TiO2) and CaO. Within a spinel-perovskite spherule from Acfer 094 periclase (MgO) and corundum (Al2O3) were found coexisting with rutile and CaO. The oxides were found as tiny single grains (50-200 nm) of rounded morphologies inside and at grain boundaries of constituent minerals of the CAIs. We suggest that these oxides are primary condensation products which did not react during the condensation process with the remaining nebular gas to form other oxides or silicates.
Lunar and Planetary Science Conference
- Pub Date:
- March 1996
- CALCIUM-ALUMINUM-RICH INCLUSIONS;
- TRANSMISSION ELECTRON MICROSCOPY