“Dogged” Search of Fresh Nakhla Surfaces Reveals New Alteration Textures

Special Issue: 74th Annual Meeting of the Meteoritical Society, August 8-12, 2011, London, U.K.International audienceCarbonaceous chondrites are considered as amongst the most primitive Solar System samples available. One of their primitive characteristics is their enrichment in volatile elements.This includes hydrogen, which is present in hydrated and hydroxylated minerals. More precisely, the mineralogy is expected to be dominated by phyllosilicates in the case of CM chondrites, and by Montmorillonite type clays in the case of CI. Here, in order to characterize and quantify the abundance of lowtemperature minerals in carbonaceous chondrites, we performed thermogravimetric analysis of matrix fragments of Tagish Lake, Murchison and Orgueil

Stardust interstellar preliminary examination - First results

Comet 26P/Grigg-Skjellerup was identified as a source of an Earth-crossing dust stream with low Earth-encounter velocities, with peak anticipated fluxes during April 2003 and 2004. In response to this prediction, NASA performed dedicated stratospheric dust collections using high altitude aircraft to target potential interplanetary dust particles (IDPs) from this comet stream. Low noble gas abundances, high abundances of large deuterium enrichments and presolar grains in IDPs from this collection are consistent with an origin from the comet Grigg-Skjellerup. Here we report a mineralogical study of 6 IDPs from 4 different clusters from the Grigg-Skjellerup collections, L2054 and L2055, using a JEOL 2500SE field-emission scanning TEM (FE-STEM). Presented at the 71st Annual Meeting of the Meteoritical Society, abstract number 5247