572 Annals New York Academy of Sciences 



terrestrial marine sediment extracts. Like most marine sediments and unlike 

 most soils, the Murray and Orgueil meteorites have benzene extractable frac- 

 tions which contain complex mixtures of carbonyl compounds (which are 

 not wax-esters) and significant concentrations of aromatic hydrocarbons and 

 free sulfur. 



Further consideration of the spectrometric data provides evidence of addi- 

 tional similarities and some dissimilarities between meteoritic and terrestrial 

 sedimental extracts. In figure 2, the 12.3 and 13.4 m absorption bands of the 

 benzene eluate of 2-()rgueil are similar to the "oil bands''^' found in the in- 

 frared spectra of the aromatic fractions of all crude oils,'*^'^' but the ultraviolet 

 (figure 5) and mass spectra (tables 6 and 8) show that the meteorite aro- 

 matic fractions are unusually simple. Aromatic mixtures in crude oils and 

 ancient sediments^^'"'-^^'^^ greatly exceed in complexity these meteoritic frac- 

 tions. Apparently, certain recent sediments are the only terrestrial samples^^' 

 39,45,46 containing naturally formed aromatic mixtures which even approach 

 in simplicity the aromatic hydrocarbons from these meteorites. 



Structural types of the major aromatic species in the Orgueil and Murray 

 fractions can be deduced from the ultraviolet (figures 3 and 4) and mass 

 (tables 6 and 8) data. The ultraviolet spectra indicate the possible aromatic 

 nuclei, and the mass data permits the elimination of some possible nuclei 

 which do not yield large parent ions in the mass spectra. Based upon the 

 ultraviolet and mass data the principal aromatic nuclei are in order of decreas- 

 ing abundance: (1) Phenanthrenes, pyrenes, and chrysenes in the Orgueil extract. 

 Most abundant aromatic hydrocarbon is phenanthrene. See 178 mass peak 

 in X = —4 column at C^ =13 in table 6. (2) Pyrenes, chrysenes, benz(j)- 

 fluoranthenes (indicated but not completely identified) and phenanthrenes in 

 the Murray extract. Most abundant aromatic hydrocarbon is pyrene. See 

 202 mass peak in x = —8 column at C j^ = 15 in table 8. 



Large "parent" ions appear in the 22 to 29 carbon number range of the even 

 .r columns in table 6. These ions are made from complex aromatic molecules 

 many of which differ in carbon and hydrogen content from aromatics reported 

 in the literature. It has been proposed^'* '^^ that naturally occurring aromatics 

 may be products of transformations of isoprenoids and steroids, and this 

 proposal has recently been supported by the identification of 21 aromatic 

 compounds in petroleum. Mair and Martinez-Pico'^'^ note that "most of the 

 ('21 aromatic') compounds are related to steroids. The results . . . give strong 

 support to the theory that steroids and other natural products related to 

 phenanthrene are petroleum precursors." Conversions of olefinic steroids 

 and terpenes to aromatics necessitate the loss of some alkyl, usually methyl 

 substituents, from the highly substituted isoprenoid ring systems. Conse- 

 (juently, aromatics formed from terpenes and steroids would contain a lower 

 number of carbon atoms than their precursors. The high concentrations of 

 largely unreported C2.S through C28 phenanthrenes, chrysenes, and pyrenes 

 indicated by the large peaks in table 6 suggest that C27 through C^o steroids 

 and triterpenoids may have been a source of the aromatics in the Orgueil 

 meteorite. This suggestion is amplified by the common prevalence of the 

 same types of nonlinear polyring aromatics in meteoritic and sedimental 



