Michel Nuevo^1,2, Scott A. Sandford¹, George J. Flynn³, Susan Wirick⁴

¹NASA Ames Research Center, MS 245-6, Moffett Field, California, USA
²SETI Institute, Mountain View, California, USA
³Department of Physics, SUNY-Plattsburgh, Plattsburgh, New York, USA
⁴Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois, USA

The Sutter’s Mill meteorite fell in northern California on April 22, 2012. Several fragments of the meteorite were recovered, some of them shortly after the fall, others several days later after a heavy rainstorm. In this work, we analyzed several samples of four fragments―SM2, SM12, SM20, and SM30―from the Sutter’s Mill meteorite with two infrared (IR) microscopes operating in the 4000–650 cm⁻¹ (2.5–15.4 μm) range. Spectra show absorption features associated with minerals such as olivines, phyllosilicates, carbonates, and possibly pyroxenes, as well as organics. Spectra of specific minerals vary from one particle to another within a given stone, and even within a single particle, indicating a nonuniform mineral composition. Infrared features associated with aliphatic CH₂ and CH₃ groups associated with organics are also seen in several spectra. However, the presence of organics in the samples studied is not clear because these features overlap with carbonate overtone bands. Finally, other samples collected within days after the rainstorm show evidence for bacterial terrestrial contamination, which indicates how quickly meteorites can be contaminated on such small scales.

Reference
Nuevo M, Sandford SA, Flynn GJ and Wirick S (in press) Mid-infrared study of stones from the Sutter’s Mill meteorite. Meteoritics & Planetary Science
[doi:10.1111/maps.12269]
Published by arrangement with John Wiley & Sons

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