Capri, Italy “Origin of Life” conference November 2005

Provenance of volatile carbon-bearing gases in carbonaceous chondrites

Mark A. Sephton¹, Ann L. Butterworth², Randall S. Perry¹.

1) IARC, Department of Earth Science and Engineering, South Kensington

Campus

Imperial College London, SW7 2AZ

2) University of California, Space Sciences Lab, 7 Gauss Way, Berkeley,

CA 94720-7450

Carbonaceous meteorites contain organic matter and carbonate minerals in

significant amounts (ca. 5 % and 0.2 % respectively). The genetic

relationship between meteoritic organic matter and carbonate is

uncertain. As both organic matter and carbonate both contain carbon, one

appropriate approach is the use of carbon isotopes to explore any common

origin. We have analysed the carbon isotopic composition of carbon

dioxide and methane from two carbonaceous chondrites, Murchison and Cold

Bokkeveld, and have compared these values with published carbonate values

for the same meteorites. The data reveal clues to the origin of the

various carbon-bearing phases and associated meteorite parent body

(asteroid) processes in the early Solar System.