Synchrotron Based Infrared Microspectroscopy of Carbonaceous Chondrites.

Relationships between organic molecules and inorganic minerals are investigated in five carbonaceous chondrites, Northwest Africa 852 (CR2), Tagish Lake (C2-ungroupped), Orgueil (CI1), Sutter's Mill (CM), and Murchison (CM2), with micron spatial resolution using synchrotron-based imaging micro-FTIR spectroscopy. Correlations based on absorption strength for various constituents are determined using statistical correlation analysis. Silicate band is found to be positively correlated with stretching modes of aliphatic hydrocarbons in NWA 852 and Tagish Lake. The former is highly correlated with the hydration band in all meteorites. Negative correlation is observed between water+organics and carbonate bands in all meteorites. Two dimensional infrared maps for NWA 852 and Orgueil show that carbonates are spatially separated from water+organic combination, silicates, OH, and CH distributions. Overlapping of the latter three in NWA 852 and Tagish Lake suggests a possible catalytic role of phyllosilicates in the formation of organics. Additionally, spectroscopic analyses on Sutter's Mill meteorite fragments present multiple distinct mineralogies. Spatial and spectral evidences on this regolith breccia suggest mixing of multiple parent bodies. Ratios of asymmetric CH2 and CH3 band strengths for NWA 852, Tagish Lake, and Sutter's Mill are similar to the average ratio of interplanetary dust particles and Wild 2 cometary dust particles, however significantly exceeds that of interstellar medium objects and several aqueously altered carbonaceous chondrites such as Orgueil. This suggests distinct formation regions and/or parent body processing of organics for these meteorites. Our infrared spectro-microtomography measurements on Murchison meteorite, representing the first such measurement on any kind of meteorite, comprise of three-dimensional reconstructions of specific molecular functional groups for understanding the spatial distributions of these groups.

Author dc:creator

• Yesiltas, Mehmet

Contributors dc:contributor

• Peale, Robert

• Infrared
• raman
• spectroscopy
• microscopy
• meteorites
• carbonaceous chondrites
• Physics
• Dissertations, Academic -- Sciences; Sciences -- Dissertations, Academic

Language dc:language

English

Identifier

CFE0006061

OAI identifier oai:identifier

oai:stars.library.ucf.edu:etd-2496