Abstract
CaAl2O4-phases in an unusual Ca-Al-Fe-rich inclusion in the Vigarano CV3 chondrite have been investigated by SEM-EBSD and TEM. The grains of CaAl2O4 phase are smaller than 400 micron in size and chemically homogeneous. In EBSD analyses, the CaAl2O4 phase showed Kikuchi patterns of the high-pressure phase with space group P21/c. On the other hand, SAED patterns of a CaAl2O4 grain could be indexed only by low-pressure phase with space group P21/n. The CaAl2O4 phase would have been crystallized from Ca-Al-Fe-rich melt as the P21/n phase together with grossite and hercynite in the solar nebula. Subsequently, the P21/n phase would have been mostly transformed into the P21/c by shock metamorphism in the Vigarano parent body.
