^1,2E.S. Steenstra, ^1,3C.J. Renggli, ¹J. Berndt, ¹S. Klemme
Geochimica et Cosmochimica Acta (in Press) Open Access Link to Article [https://doi.org/10.1016/j.gca.2024.08.021]
¹Institute of Mineralogy, University of Münster, Germany
²Faculty of Aerospace Engineering, Technische Universiteit Delft, the Netherlands
³Max Planck Institute for Solar System Research, Göttingen, Germany
Copyright Elsevier

The processes responsible for the isotopic compositions and abundances of volatile elements in the early solar system remain highly debated. Orders of magnitude variation of (highly) volatile elements exist between different magmatic iron meteorite groups, but it is unclear to what extent their depletions can be explained by evaporation from metal melts during parent body accretion and/or subsequent break up. To this end, we present 86 new evaporation experiments with the aim of constraining the volatility of most volatile metals from metallic melts. The results confirm the previously proposed important effects of S in metal melt on the volatility of the elements of interest governed by their S-loving or S-phobic behavior. Nominally S-loving elements In, Sn, Te, Pb and Bi are significantly more volatile in Fe melt relative to FeS liquid, whereas nominally S-avoiding elements Ga and Sb are more volatile in FeS liquid relative to Fe melt, at a given pressure and temperature. The newly derived volatility sequences for S-free/poor and S-rich metallic melts were also compared with commonly used volatility models based on condensation temperatures. The results indicate significant differences between the latter, including the much more volatile behavior of Te, relative to Se, in both explored bulk compositions, which are traditionally assumed to be equally volatile. The (minimum) degree of volatile element depletion due to evaporation was quantified using the new experimental results and models. A comparison between the volatile element depletions in magmatic iron meteorites and the predicted depletions appropriate for evaporation from Fe melts shows that the latter depletions can be easily reconciled with (an) evaporation event(s). Altogether, the new data and models will provide an important framework when more accurate and precise estimates of magmatic iron meteorite bulk volatile element contents are available.

^1,2A. Musolino,^1,3M. D. Suttle,^1,4L. Folco,⁵A. J. King,^6,7G. Poggiali,⁵H. C. Bates,⁶J. R. Brucato,⁸A. Brearley
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14261]
¹Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy
²Aix-Marseille Université, CEREGE, CNRS, IRD, Aix-en-Provence, France
³School of Physical Sciences, The Open University, Walton Hall, Milton Keynes, UK
⁴CISUP, Centro per l’Integrazione della Strumentazione dell’Università di Pisa, Pisa, Italy
⁵Planetary Materials Group, Natural History Museum, London, UK
⁶INAF-Astrophysical Observatory of Arcetri, Florence, Italy
⁷LESIA-Observatoire de Paris, PSL University, Paris, France
⁸UNM, Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico, USA
Published by arrangement with John Wiley & Sons

Reckling Peak (RKP) 17085 is a newly classified Antarctic CM chondrite that preserves a complex alteration history characterized by mild aqueous alteration (CM2.7), overprinted by a short-lived thermal metamorphic event (heating stage III [<750°C]), and affected by low-grade terrestrial weathering. This meteorite contains abundant Fe-rich bands within the fine-grained matrix, composed of micron-scale Fe-oxyhydroxide minerals. They are interpreted as “alteration fronts” arising due to the dissolution and transport of Fe (typically <500 μm) before being abruptly deposited. This alteration texture is relatively rare among hydrated carbonaceous chondrites, with only five reported instances to date (Murchison, Murray, Allan Hills 81002, Miller Range 07687, and Northwest Africa 5958). Evidence from RKP 17085 suggests that early aqueous alteration operated as multiple geochemically isolated microenvironments, which moved outwards from local point sources within the matrix. Low permeability fine-grained rims on chondrules appear to have acted as barriers to fluid flow, controlling the migration of fluid across the parent body. Furthermore, the higher porosity regions within the altered fine-grained matrix represent either void space generated by the dehydration of hydrated minerals during post-hydration metamorphism and/or sites of ice accretion (water-ice or C-bearing ices) preserved within a mildly altered primitive matrix.