The Iron, Magnesium and Calcium Distribution in Coexisting Olivines and Rhombic Pyroxenes of Chondrites

摘要

Iron, magnesium, and calcium analyzed in olivines and pyroxenes of 95 chonditic meteorites with an electron microprobe. Of these, 86 were ‘ordinary’ chondrites, each of which has constant iron magnesium ratios in olivine and problems. Nor is the ferrous iron strictly related to the amount of metallic nickel-iron. Thus Prior’s rule is not valid in its original sense, although it can be applied qualitatively when comparing the different groups of chondrites. It is demonstrated that coexisting olivines and pyroxenes are not in equilibuium in spite of their constant composition and the constant ratio between their iron contents. Furthermore, the metallic nickel-iron seems to have originated in the same melt as did the silicates