Meteoroid atmospheric entry investigated with plasma flow experiments: Petrography and geochemistry of the recovered material

Autor(en)
Lidia Pittarello, Steven Goderis, Bastien Soens, Seann McKibbin, Gabriele Giuli, Federico Bariselli, Bruno Dias, Bernd Helber, Giovanni Lepore, Frank Vanhaecke, Christian Koeberl, Thierry Magin, Philippe Claeys
Abstrakt

Melting experiments attempting to reproduce some of the processes affecting asteroidal and cometary material during atmospheric entry have been performed in a high enthalpy facility. For the first time with the specific experimental setup, the resulting material has been recovered, studied, and compared with natural analogues, focusing on the thermal and redox reactions triggered by interaction between the melt and the atmospheric gases under high temperature and low pressure conditions. Experimental conditions were tested across a range of parameters, such as heat flux, experiment duration, and pressure, using two types of sample holders materials, namely cork and graphite. A basalt served as asteroidal analog and to calibrate the experiments, before melting a H5 ordinary chondrite meteorite. The quenched melt recovered after the experiments has been analyzed by mu-XRF, EDS-SEM, EMPA, LA-ICP-MS, and XANES spectroscopy.

The glass formed from the basalt is fairly homogeneous, depleted in highly volatile elements (e.g., Na, K), relatively enriched in moderately siderophile elements (e.g., Co, Ni), and has reached an equilibrium redox state with a lower Fe3+/Fe-tot ratio than that in the starting material. Spherical objects, enriched in SiO2, Na2O and K2O, were observed, inferring condensation from the vaporized material. Despite instantaneous quenching, the melt formed from the ordinary chondrite shows extensive crystallization of mostly olivine and magnetite, the latter indicative of oxygen fugacity compatible with presence of both Fe2+ and Fe3+. Similar features have been observed in natural meteorite fusion crusts and in micrometeorites, implying that, at least in terms of maximum temperature reached and chemical reactions, the experiments have successfully reproduced the conditions likely encountered by extraterrestrial material following atmospheric entry.

Organisation(en)
Department für Lithosphärenforschung
Externe Organisation(en)
Georg-August-Universität Göttingen, Institut Von Karman de Dynamique des Fluides, European Synchrotron Radiation Facility ESRF, Naturhistorisches Museum Wien (NHM), Vrije Universiteit Brussel, Università degli Studi di Camerino, Ghent University
Journal
Icarus
Band
331
Seiten
170-178
Anzahl der Seiten
9
ISSN
0019-1035
DOI
https://doi.org/10.1016/j.icarus.2019.04.033
Publikationsdatum
2019
Peer-reviewed
Ja
ÖFOS 2012
105105 Geochemie, 105119 Petrographie
Schlagwörter
ASJC Scopus Sachgebiete
Astronomy and Astrophysics, Space and Planetary Science
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/meteoroid-atmospheric-entry-investigated-with-plasma-flow-experiments-petrography-and-geochemistry-of-the-recovered-material(22c125f9-22d7-40b7-90dc-137e33ad05f9).html