Olivine and pyroxene compositions of chondritic interplanetary dust particles

We report here analyses of olivines and pyroxenes, and petrofabrics of 27 chondritic IDPs, comparing those from anhydrous and hydrous types. Based on mineralogical evidence, principally the occurrence in some of diopside, we find that hydrous and anhydrous IDPs are, in general, not directly related. The particles containing diopside must have come from parent bodies which experienced extensive low‐temperature thermal metamorphism.