Meinschein et al. : Evidence in Meteorites of Former Life 569 



in the sediments on earth are the most acceptable standards for the identifica- 

 tion of former life in meteorites. 



Numerous soils and marine sediments have been analyzed by methods 

 analogous to those used in this investigation of the Murray and Orgueil carbona- 

 ceous chondrites. Additional analyses have been run on saturated hydro- 

 carbons from sediments, plants, and animals. A review of these investigations 

 of terrestrial samples will serve as a basis for evaluating the analyses of the 

 meteoritic hydrocarbons. 



Smith^" found that geologically young hydrocarbons (C* ages 9000 to 14000 

 years) isolated from recent sediments have optical activities, infrared spectra, 

 elemental and type compositions, and chromatographic properties equivalent 

 to hydrocarbons in ancient crude oils. Oakwood^' plotted optical activities 

 versus distillation temperatures for hydrocarbons from kelp (a seaweed) and 

 crude oil, and he observed that these similar plots peaked in the same tempera- 

 ture region.*-' Saturated hydrocarbons in mixtures of plant and animal lipids, 

 recent and ancient sediments, and crude oils seem to have equivalent chromato- 

 graphic properties and infrared spectra, and similar mass spectrometric cracking 

 patterns.^'* C^^ ages^"'*'* and //-paraffin distributions^^ •^**-''^'^^-*^-"^ provide the 

 only reported means of distinguishing between the Cu and larger saturated 

 hydrocarbons in recent sediments and those in crude oils. 



Wax-esters, closely re.sembling beeswax, have been found in a variety of 

 types of soils from arid and humid areas of tropical and temperate regions of 

 the world.^^ Blumer^*^ has identified in soils the same aromatic hydrocarbons 

 that have been identified in marine sediments.^^ Hunf*^"*^ and Brenneman^" 

 have reported similarities between hydrocarbons dispersed in ancient sediments 

 and concentrated in crude oils. Bray^' has observed that the aromatic frac- 

 tions of all crude oils absorb near 12.35 and lvS.45 m in the infrared.*^ He has 

 referred to these absorptions as "oil bands." 



2,6,10,14-Tetramethylpentadecane, pristane, is a norisoprenoid hydro- 

 carbon constituent of fish oils.^-'^'' Pristane forms 0.2 and 0.5 per cent, respec- 

 tively, of the two crude oils in which it was measured. ^^ 2,6,10,14-Tetra- 

 methylhexadecane, phytane, is a diterpenoid or isoprenoid which is, also, a 

 common component of fish and crude oils.^^ The concentrations of phytane 

 in 10 Iranian oils is to be reported. ^^ It is of interest that the first Cu, or 

 larger, branched paraffins, pristane and phytane, isolated from crude oils are 

 of an isoprenoid type.'^^ 



When the possible complexity of petroleum is considered, the relatively 

 high concentrations of pristane and the measurable quantities of phytane in 

 crude oils is noteworthy. There are in excess of 100,000 possible isomers of 

 Ci9 and 366,319 possible isomers of Con paraffins.^'' Because crude oils contain 

 hydrocarbons composed of more than 50 carbon atoms, the number of paraffins, 

 cycloalkanes, and aromatic compounds that might form petroleum is astronomi- 

 cally large and of the order of 10'** different hydrocarbons. Because of the 

 diversity of compound types and the large range of carbon atom contents of 

 the hydrocarbons in petroleum, the abundances of pristane and phytane in 

 crude oils suggest a highly selective synthesis of these compounds. The com- 

 mon presence of the precisely structured pristane and phytane in fish and 

 crude oils may be more than fortuitous. Possibly certain of the stable saturated 



