Physical and Mineralogical Properties of Anhydrous Interplanetary Dust Particles in the Analytical Electron Microscope

Abstract

AbstractThe fine grained mineralogy and petrography of anhydrous “pyroxene” and “olivine” classes of chondritic interplanetary dust have been investigated by numerous electron microscopic studies. The “pyroxene” interplanetary dust particles (IDPs) are porous, unequilibrated assemblages of mineral grains, metal, glass, and carbonaceous material. They contain enstatite whiskers, FeNi carbides, and high-Mn olivines and pyroxenes, all of which are likely to be well preserved products of nebular gas reactions. Solar flare tracks are prominent in most “pyroxene” IDPs, indicating that they were not strongly heated during atmospheric entry. The “olivine” IDPs are coarse grained, equilibrated mineral assemblages that have probably experienced strong heating. Since most “olivine” IDPs do not contain tracks, it is possible that this heating occurred during atmospheric entry.