Evolution of organic matter in Orgueil, Murchison and Renazzo during parent body aqueous alteration: in-situ investigations
Le Guillou C, Bernard S, Brearley AJ and Remusat L
Geochimica et Cosmochimica Acta
Volume 131, 15 April 2014, Pages 368–392
In contrast to Renazzo, organic grains in Murchison and Orgueil display strong chemical heterogeneities, likely related to chemical evolution during aqueous alteration. The observations suggest that the altering fluid was a brine with elevated concentrations of both organic and inorganic soluble components. Ultimately, when water was consumed by aqueous alteration reactions or lost from the system, soluble organic compounds accumulated in the immediate vicinity of the precipitated carbonates and phosphates. Additionally, the nanometer scale organic/phyllosilicate relationships provide a petrological environment where some of the initially accreted organic matter could have been modified through clay-mediated reactions.