174 ABIOGENIC ORGANIC-CHEMICAL EVOLUTION 



of the crust of the Earth but it would seem not to be these 

 which play the decisive part in the formation of petroleum, 

 but rather the catalytic activity of the mineral formations. 

 In particular, A. V. Frost*^ has shown that those reactions 

 which, in the laboratory, are catalysed by anhydrous alu- 

 minium chloride can also take place in the presence of various 

 natural clays (kaolins, bauxites and other aluminosilicates) 

 without any preliminary treatment or activation/^ 



Similarly, the transformations of the primary hydrocarbons 

 which have already been described may take place in the 

 crust of the Earth, being catalysed by oxides of aluminium, 

 iron, chromium and manganese and by other substances 

 which are widely distributed in the lithosphere. 



The multiplicity of possible chemical transformations is 

 further considerably increased in the crust of the Earth 

 by the influence of the decay of the radioactive elements 

 which are present there. Under these conditions reactions 

 can occur which would be prohibited by thermodynamic 

 considerations from occurring on their own. Among these 

 we may mention the formation of acetaldehyde by the 

 reaction between methane and carbon monoxide and the 

 dehydrogenation of methane and its polymerisation, which 

 have already been discussed in relation to the work of V. 

 Sokolov, as well as other reactions. 



One of the first to point out the possible significance of 

 radioactive substances in the formation of petroleum was 

 N. Zelinskii.'' As early as 1925 V. Sokolov*' produced evi- 

 dence for the occurrence of natural radioactivity in clays and 

 other geological formations. I. A. Breger and W. L. White- 

 head,** A. Kozlov,** M. Karasev,*^ and many other workers 

 have also studied the significance of radioactivity in the 

 formation of petroleum. 



One can, however, hardly regard (as some authors do) the 

 radioactivity of geological formations as being solely respons- 

 ible for the origin of the hydrocarbons which were first 

 formed in the crust of the Earth. Direct catalytic transforma- 

 tions must certainly have been more important quantita- 

 tively. Radioactive radiations may, however, have been 

 responsible for the occurrence of reactions which would 

 otherwise have been impossible on thermodynamic grounds. 



