Nature of the Clinoenstatite Rim in Refractory Forsterite-Rich Objects from Carbonaceous Chondrites: First Results of Study by the Method of Electron Backscatter Diffraction (EBSD)

A clinoenstatite rim occurs in many refractory forsterite-rich objects; however, specialized studies of it have not been carried out. The first data from the study of refractory forsterite-rich objects by electron backscatter diffraction (EBSD) are reported. It is shown that the clinoenstatite rim in refractory forsterite-rich inclusions has a reactionary nature and was formed as a result of nebular processes. The rim is almost entirely composed of clinoenstatite. Forsterite grains have a block internal structure with a maximum misorientation angle of 10° within a single crystal.