Infrared imaging spectroscopy with micron resolution of Sutter's Mill meteorite grains     

Mehmet Yesiltas  Yoko Kebukawa  Robert E. Peale  Eric Mattson  Carol J. Hirschmugl  Peter Jenniskens 《Meteoritics & planetary science》2014,49(11):2027-2037

Synchrotron‐based Fourier transform infrared spectroscopy and Raman spectroscopy are applied with submicrometer spatial resolution to multiple grains of Sutter's Mill meteorite, a regolith breccia with CM1 and CM2 lithologies. The Raman and infrared active functional groups reveal the nature and distribution of organic and mineral components and confirm that SM12 reached higher metamorphism temperatures than SM2. The spatial distributions of carbonates and organic matter are negatively correlated. The spatial distributions of aliphatic organic matter and OH relative to the distributions of silicates in SM2 differ from those in SM12, supporting a hypothesis that the parent body of Sutter's Mill is a combination of multiple bodies with different origins. The high aliphatic CH₂/CH₃ ratios determined from band intensities for SM2 and SM12 grains are similar to those of IDPs and less altered carbonaceous chondrites, and they are significantly higher than those in other CM chondrites and diffuse ISM objects.  相似文献   

Organic and inorganic correlations for Northwest Africa 852 by synchrotron‐based Fourier transform infrared microspectroscopy          下载免费PDF全文

Mehmet Yesiltas  Robert E. Peale  Miriam Unger  Julia Sedlmair  Carol J. Hirschmugl 《Meteoritics & planetary science》2015,50(10):1684-1696

Relationships between organic molecules and inorganic minerals are investigated in a single 34 μm diameter grain of the CR2 chondrite Northwest Africa 852 (NWA) 852 with submicron spatial resolution using synchrotron‐based imaging micro‐FTIR spectroscopy. Correlations based on absorption strength for the various constituents are determined using statistical correlation analysis. The silicate band is found to be correlated with the hydration band, and the latter is highly correlated with stretching modes of aliphatic hydrocarbons. Spatial distribution maps show that water+organic combination, silicate, OH, and C‐H distributions overlap, suggesting a possible catalytic role of phyllosilicates in the formation of organics. In contrast, the carbonate band is anticorrelated with water+organic combination, however uncorrelated with any other spectral feature. The average ratio of asymmetric CH₂ and CH₃ band strengths (CH₂/CH₃ = 2.53) for NWA 852 is similar to the average ratio of interplanetary dust particles (~2.40) and Wild 2 cometary dust particles (2.50), but it significantly exceeds that of interstellar medium objects (~1.00) and several aqueously altered carbonaceous chondrites (~1.40). This suggests organics of similar length/branching, and perhaps similar formation regions, for NWA 852, Wild 2 dust particles, and interplanetary dust particles. The heterogeneous spatial distribution of ratio values indicates the presence of a mixture of aliphatic organic material with different length/branching, and thus a wide range of parent body processes, which occurred before the considered grain was formed.  相似文献