Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 1982 | public
Journal Article

Carbon, hydrogen and nitrogen isotopes in solvent-extractable organic matter from carbonaceous chondrites

Abstract

Solvent extractions were done on the carbonaceous chondrites Murray, Murchison, Orgueil and Renazzo, using CCl_4 and CH_3OH. Between 2 and 10% of the total carbon in these meteorites is extractable by ordinary techniques, most of it in CH_3OH. After demineralization with HF, perhaps as much as 30% of the total carbon in Murray may be extractable with CH_3OH. The extracts from Renazzo have isotopic ratios which suggest that they are mainly terrestrial organic matter, with lesser contributions from indigenous organics. The CH_3OH-soluble organic matter from Murchison and both untreated and HF-treated Murray has δ^(13)C values of about +5 to +10%. and δ^(15)N values of about +90 to +100%., both of which are significantly higher than the bulk meteorite values. The Orgueil CH_3OH-extract also has a δ^(15)N value well above the value in residual organic matter. Values for δD of +300 to +500%. are found for the CH_3OH-soluble organic matter. The combined data for C, H and N isotopes makes it highly unlikely that the CH_3OH-soluble components are derivable from, or simply related to, the insoluble organic polymer found in the same meteorites. A relationship is suggested between the event that formed hydrous minerals in CI1 and CM2 meteorites and the introduction of water-soluble (methanol-soluble) organic compounds. Organic matter soluble in CCl_4 has essentially no nitrogen, and δ^(13)C and δD values are lower than for CH_3OH-soluble phases. Either there are large isotopic fractionations for carbon and hydrogen between different soluble organic phases, or the less polar components are partially of terrestrial origin.

Additional Information

© 1982 Pergamon Press Ltd. Received October 20, 1980; accepted in revised form September 15, 1981. We thank Dr. P. Pellas, Dr. C. B. Moore and Dr. E. Olsen for samples of the meteorites used in this study. We thank F. Robert for helpful discussions. This paper was improved by helpful reviews from Dr. E. Anders, Dr. J. M. Hayes and Dr. S. Chang. Support was provided by NASA grant number NGL-05-002-190.

Additional details

Created:
August 19, 2023
Modified:
October 25, 2023