Hydrocarbons in terrestrial samples and the Orgueil meteorite

Abstract

Meteorites contain extraterrestrial carbonaceous materials. The Alais, Orgueil, Tonk, and Ivuna meteorites resemble in their carbon, free sulfur, and non-metamorphosed mineral contents, densities, and general appearances certain organic-rich terrestrial sediments. Structural and isotopic determinations of carbon compounds in the Orgueil chondrite indicate that these compounds are primarily indigenous. Physically and chemically the benzene extractable carbonaceous materials from the Orgueil and certain near-surface terrestrial sediments are similar. Mass spectrometric type analyses of the alkanes from an Orgueil fragment, terrestrial sediments and organisms are statistically indistinguishable at the 95 per cent confidence level. Theoretical considerations and experimental data are presented, and these permit an assessment of the potential and reliability of hydrocarbons as biological indicators. Based on the production and preservation or organic substances in terrestrial environments, alkanes in the Alais, Orgueil, Tonk, and Ivuna (Type I) carbonaceous chondrites could retain the best evidence of organisms that may have lived on a parent body of meteorites.

Organic compounds in carbonaceous meteorites

“…As a result, alkanes were also detected in Alais (CI1), Tonk (CI1), Ivuna (CI1) and Murray (CM2). [45][46][47] The interpretations of these findings followed a similar format to those for Orgueil (CI1), as the n-alkanes in these carbonaceous chondrites were proposed as "evidence of organisms that may have lived on a parent body of meteorites". 46 The distribution of n-alkanes in Orgueil (CI1) was investigated by Oró et al, 85 who used a similar experimental scheme to Meinschein et al, [45][46][47] to isolate and identify these compounds.…”

“…[45][46][47] The interpretations of these findings followed a similar format to those for Orgueil (CI1), as the n-alkanes in these carbonaceous chondrites were proposed as "evidence of organisms that may have lived on a parent body of meteorites". 46 The distribution of n-alkanes in Orgueil (CI1) was investigated by Oró et al, 85 who used a similar experimental scheme to Meinschein et al, [45][46][47] to isolate and identify these compounds. By analysing both interior and exterior portions of Orgueil (CI1), it was established that these hydrocarbons decreased in abundance away from the surface of the meteorite.…”

The Origin and Evolution of Organic Matter in Carbonaceous Chondrites and Links to Their Parent Bodies

“…These studies led to many reports of aliphatic hydrocarbons in meteorites, as well as to debate over the origin (terrestrial or extraterrestrial) of these compounds. Aliphatic hydrocarbons were reported from the Orgueil meteorite and were controversially claimed to be potential evidence of biological activity (Meinschein, 1963a;Nagy et al, 1961); similar claims were made for alkanes detected in other carbonaceous chondrites, including Alais, Ivuna, and Murray (Meinschein, 1963a;Meinschein, 1963b;Meinschein et al, 1963). Kvenvolden et al (1970b) reported a complex mixture of alkanes, including cycloalkanes, in the Murchison meteorite.…”

Gas-Chromatographic Mass-Spectrometric Studies on the Isoprenoids and Other Isomeric Alkanes in Meteorites

“…The presence of cyclohexylalkanes or olefins in carbonaceous chondrites had been previously suggested [16,17]. The presence of cyclohexylalkanes or olefins in carbonaceous chondrites had been previously suggested [16,17].…”