Compound-specific isotopic study of carbonaceous choandrites

Compound-specific isotopic study of carbonaceous choandrites: implications for the origin of meteoritic organic compounds. Compound-specific isotopic ratios provide unique insights into the origin and synthetic pathways of organic compounds in carbonaceous meteorites by allowing both recognition of terrestrial contaminants and an understanding of their synthetic histories and genetic relationships.

Despite recent progress, molecular isotopic data available have been limited to a narrow range of organic compounds and to a few meteorites, Murchison, Tagish Lake and Orgueil. We propose to expand our research to all common classes of organic compounds in Murchison and in a suite of Antarctic carbonaceous meteorites in order to answer following outstanding questions: 1) what are the range and variability of isotopic ratios of individual compounds in carbonaceous chondrites? 2) what are the fundamental mechanisms controlling the variability in isotopic compositions? 3) how can molecular isotopic signatures be used to infer the origins of meteoritic organic compounds?

We will apply compound-specific C and H isotopic analysis to soluble organic compounds and insoluble macromolecules in Murchison and Antarctic carbonaceous meteorites. Large isotopic variations, revealed both within a single class of compounds and between the organic suites of different meteorites such as Murchison and Tagish Lake, have suggested multiple synthetic pathways and alteration mechanisms for meteoritic organic compounds. A systematic isotopic study on Murchison and a broader suite of Antarctic carbonaceous meteorites, coupled with mineralogical characterization, will allow us to:

• Determine the full range of C and H isotopic variability in different compounds and in different meteorites;


• Synthesize results from isotopic, molecular and mineralogical data to better infer the genetic relationship and synthetic mechanisms of organic compounds and the history of aqueous and thermal alteration;


• Continue the development of analytical procedures to characterize meteoritic organic compounds.

Brown faculty collaborators:

None

Other project collaborators: