An Investigation of Carbon Isotope Abundances in ALH84001

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This award in the Mars-Rock Special Research Opportunity activity supports study of carbon-14 abundances in martian meteorites by Dr. Greg H. Rau of the Institute of Marine Sciences, University of California, Santa Cruz. The project is funded by the Office of Polar Programs, the Chemistry Division, and the MPS Office of Multidisciplinary Activities. Carbon isotopic measurements (C-13/C-12 ratio and C-14 concentration) will be conducted on carbon collected from the ALH84001 meteorite using discrete inorganic and organic carbon extraction techniques. The goal of the project is to gain a better understanding of the sources and possible martian biogenicity of carbon contained in the meteorite. The work will be conducted as part of a collaborative research project based at NASA-Ames Research Center where individual acid, UV-laser ablation, and stepped heating extractions will be performed on AHL84001 samples and terrestrial analogs. Isotopic analysis will be performed on the carbon dioxide released from these extraction fractions. The mass and isotopic abundances within the organic and inorganic fractions will be determined, as well as the degree of terrestrial contamination of each fraction, and the isotopic carbon ratio of both the meteorite organic and inorganic carbon. The results will be interpreted in the context of Martian geology and climate. It is likely that terrestrial carbon contamination may have influenced the meteorite's organic carbon concentration, and this will be considered in order to accurately infer Martian organic/inorganic carbon isotope abundances, fractionations, and organic carbon formation process. Carbon in planetary samples may be present in inorganic forms or may have been modified by biological activity. As a result of either physical or biological forces, the isotopic composition of carbon in the sample may have been altered to provide a distinctive `signature.` This research brings together a unique combination of carbon isotope extertise from NASA-Ames, the University of California, and the Lawrence Livermore National Laboratory to investigate both terrestrial and meteorite samples. The results will aid in determining whether or not the evidence from martian meteorite ALH84001 is consistent with biological activity.