Thermal Alteration of Labile Elements in Carbonaceous ChondritesOPEN ACCESS 

Alessondra Springmann, Dante S. Lauretta, Bjoern Klaue, Yulia S. Goreva, Joel D. Blum, Alexandre Andronikov, Jordan K. Steckloff

submitted to Icarus

PDF (OPEN ACCESS)

“Carbonaceous chondrite meteorites are some of the oldest Solar System planetary materials available for study. The CI group has bulk abundances of elements similar to that of the solar photosphere. Of particular interest in carbonaceous chondrite compositions are labile elements, which vaporize and mobilize efficiently during post-accretionary parent body heating events. Thus, they can record low-temperature alteration events throughout asteroid evolution. However, the precise nature of labile-element mobilization in planetary materials is unknown. Here we characterize the thermally induced movements of the labile elements S, As, Se, Te, Cd, Sb, and Hg in carbonaceous chondrites by conducting experimental simulations of volatile-element mobilization during thermal metamorphism. This process results in appreciable loss of some elements at temperatures as low as 500 K. This work builds on previous laboratory heating experiments on primitive meteorites and shows the sensitivity of chondrite compositions to excursions in temperature. Elements such as S and Hg have the most active response to temperature across different meteorite groups. Labile element mobilization in primitive meteorites is essential for quantifying elemental fractionation that occurred on asteroids early in Solar System history. This work is relevant to resurfacing processes of near-Earth asteroids, the thermal history of “rock comets,” and the effects of temperature on maintaining a pristine sample to be returned by the OSIRIS-REx mission from asteroid (101955) Bennu. This work is also critical for constraining the concentrations of contaminants in vaporized water extracted from asteroid regolith as part of future in situ resource utilization for sustained human space exploration.”