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@inproceedings{Genge:2017,
author = {Genge, MJ and Russell, SS},
title = {A MICROCHONDRULE-BEARING MICROMETEORITE.},
url = {https://www.hou.usra.edu/meetings/metsoc2017/eposter/6107.pdf},
year = {2017}
}
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TY - CPAPER
AB - Introduction: The Earth receives a continuous flux of cosmic dust derived from young disrupted asteroids andsublimating short period comets [1,2]. Occasionally unique micrometeorites with distinct petrographies are reported[3]. These samples expand the inventory of asteroid parent bodies and provide further clues to the formation andevolution of the solar system. In this study we report the discovery of an unusual dehydroxylated fine-grained micrometeoritecontaining a devitrified microchondrule droplet. This spherule contains a volatile-rich composition indicatingformation in an energetic high density plume.Methods: A single micrometeorite, recovered from the Cap Prudhomme blue-ice micrometeorite collection [4]was analysed by SEM-EMPA, BSE, X-ray element mapping and mid-IR spectroscopy.Results: Particle CP94-050-182 (78x108μm) is a fine-grained micrometeorite, surrounded by a partial magnetiterim. A single spherical object (<10μm diameter) composed of devitrified glass is located near the micrometeorite’sperimeter and contains a non-chondritic volatile-rich composition. Relative to Ivuna, Na, K and Cl concentrations areelevated an order of magnitude above chondritic values at 7.8, 19.8 and 9.4 times, while refractory Al and Ca showapproximately chondritic abundances. The internal mineralogy is a heterogeneous mix of anhydrous silicates suspendedin a fine-grained, porous, nanocrystalline groundmass. Anhydrous silicates are present either as low-Fe(<3wt%), Ca-rich (12-15wt%) pyroxene or high-Fe (~18wt%), Ca-poor (<0.5wt%) olivine. Pyroxene grains containmoderate Mn (0.8-1.7wt%), Cr (~1.4wt%) and Al (~2.0wt%) concentrations, while olivines contain minimal traceelement contamination (Mn,Cr,Al<0.8wt%). Both anhydrous phases appear as anhedral clusters or isolated grains,intergrown with, or mantled by, a coarse non-stoichiometric Fe-rich phase. The surrounding groundmass containsrandomly orientated dehydration cracks and rounded submicron vesicles.
AU - Genge,MJ
AU - Russell,SS
PY - 2017///
TI - A MICROCHONDRULE-BEARING MICROMETEORITE.
UR - https://www.hou.usra.edu/meetings/metsoc2017/eposter/6107.pdf
ER -