Compositional variations of olivines and pyroxenes in chondritic interplanetary dust particles

It is commonly held that hydrated interplanetary dust particles (IDP's) experienced aqueous alteration on hydrous asteroids, while the anhydrous IDP's could be derived from the more primitive asteroids and comets. We wish to discover whether the anhydrous IDPs are actually from the same parent body, being related by aqueous alteration of one to produce the other. We report here analyses of olivines and pyroxenes, and petrofabrics of 27 chondritic IDP's, comparing those from anhydrous and hydrous types. Based on mineralogical evidence, we find that hydrous and anhydrous IDP's are, in general, not directly related.