Sutter's Mill dicarboxylic acids as possible tracers of parent‐body alteration processes

• Published in: Meteoritics & Planetary Science
• Main Authors: Pizzarello, Sandra, Garvie, Laurence A. J.
• Other Authors: National Aeronautics and Space Administration
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Murchison; Tagish; Tagish Lake
• Online Access: http://dx.doi.org/10.1111/maps.12264; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmaps.12264; https://onlinelibrary.wiley.com/doi/pdf/10.1111/maps.12264; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/maps.12264

Abstract Dicarboxylic acids were searched for in three Sutter's Mill ( SM ) fragments ( SM 2 collected prerain, SM 12, and SM 41) and found to occur almost exclusively as linear species of 3‐ to 14‐carbon long. Between these, concentrations were low, with measured quantities typically less than 10 nmole g −1 of meteorite and a maximum of 6.8 nmole g −1 of meteorite for suberic acid in SM 12. The SM acids' molecular distribution is consistent with a nonbiological origin and differs from those of CM s, such as Murchison or Murray, and of some stones of the C2‐ungrouped Tagish Lake meteorite, where they are abundant and varied. Powder X‐ray diffraction of SM 12 and SM 41 show them to be dominated by clays/amorphous material, with lesser amounts of Fe‐sulfides, magnetite, and calcite. Thermal gravimetric ( TG ) analysis shows mass losses up to 1000 °C of 11.4% ( SM 12) and 9.4% ( SM 41). These losses are low compared with other clay‐rich carbonaceous chondrites, such as Murchison (14.5%) and Orgueil (21.1%). The TG data are indicative of partially dehydrated clays, in accordance with published work on SM 2, for which mineralogical studies suggest asteroidal heating to around 500 °C. In view of these compositional traits and mineralogical features, it is suggested that the dicarboxylic acids observed in the SM fragments we analyzed likely represent a combination of molecular species original to the meteorite as well as secondary products formed during parent‐body alteration processes, such as asteroidal heating.