¹Valentine Megevand, ¹Sylvain Bernard, ²Corentin Le Guillou, ²Roberto Conconi, ¹François Guyot
Meteoritics & Planetary Science (in Press) Open Source Link to Article [DOI: 10.1111/maps.70214]
¹Institut de Minéralogie, Physique des Matériaux et Cosmochimie, Muséum National d’Histoire Naturelle, Centre National de la Recherche Scientifique UMR 7590, Sorbonne Université, Paris, France
²Université de Lille, CNRS, INRA, Centrale Lille, UMR 8207 – UMET – Unité Matériaux et Transformations, Villeneuve d’Ascq, France
Published by arrangement with John Wiley & Sons

Carbonaceous chondrites contain phosphorus, whose speciation and thus history remain to be investigated. Phosphorus/sulfur-bearing assemblages have been reported in carbonaceous CM chondrites, but there is no consensus about their exact compositions and origins. Here, we present submicrometer-scale investigations by analytical transmission electron microscopy of phosphorus/sulfur-bearing assemblages from the CM chondrites Murray and Murchison. Results indicate that, in CM chondrites, phosphorus associated with sulfides occurs under distinct oxidation states. In Murray, we identified a pyrrhotite–schreibersite nanocrystalline assemblage associated with carlsbergite and chromite. Its reduced nature and petrographic context are indicative of a nebular formation mechanism, possibly through kamacite sulfidation. In contrast, Murchison contains nanocrystalline pentlandite assemblages associated with carlsbergite and likely with phosphate phases that we interpret as being produced via interactions with an oxidizing fluid under asteroidal conditions. Thermodynamic modeling suggests that such complex assemblages hosting reactive forms of both phosphorus and nitrogen could promote the synthesis of activated phosphate species such as diamidophosphate, an efficient phosphorylation reagent, thereby underscoring their potential prebiotic significance.