Conditions for Appearance of Life on Earth 89 



physicists call the granite layer of the Earth's crust. The presence of free hydrogen 

 and methane in volcanic gases, and the discovery of Hquid hydrocarbons and 

 sohd paraffins in the basalt lava of Mt. Etna and in products of volcanic erup- 

 tions on the Island of Java indicate that hydrocarbons are met in the magma of 

 the basic (basaltic) and ultra-basic (peridotitic) composition, forming in still 

 deeper layers of the Earth. Stony meteorites, which are considered as analogues 

 of the Sima layer ultra-basic rocks, contain gases with 4-2% of CH4 and 17-6% 

 of H2. In the carbonaceous varieties of stony meteorites, paraffin matter is found, 

 composed of carbon (80-84-9%) and hydrogen (15-20%). Some meteorites 

 have the specific odour of heavy remains of crude oil [24-27]. 



Thus, various facts indicate that the vertical range of migration of hydro- 

 carbons is very great. Not only methane, but more complex hydrocarbons too 

 can rise to the upper layers of the Earth's crust from the crystalline basement 

 and the deeper subcrustal layers of the sohd mantle of the Earth, formed of 

 ultrabasic material. The peculiar gas deposits of so-called condensate pools, 

 found during the last decades at the deepest levels of oil deposits (2-8 to 4 km 

 deep), may be samples of these deep fluids. A condensation of such fluids at a 

 decreasing pressure produces Uquid methane, oil and combustible gases. 



THE GEOCHEMICAL ASSOCIATES OF PETROLEUM: 

 METHANE, HYDROGEN, NITROGEN, AND HELIUM 



Gaseous hydrocarbons, free hydrogen, nitrogen, and helium, i.e. gases the 

 deep origin of which becomes more and more evident (Fig. 2), are the charac- 

 teristic geochemical associates of petroleimi. The gas pressure at the deep 

 horizons is so great (combustible gases up to 880 atm, nitrogen up to 20 atm and 

 more) that it cannot be explained by biochemical processes or by the capture of 

 atmospheric gases. The high pressure of subterranean gases shows that they 

 come from the depths. V. I. Vernadskii, who long ago considered the Earth as 

 a cold and sohd cosmic body with scatterings of separate nidi of magmatic 

 melts, was the first to note the grandiose scale at which the deep juvenile gases 

 (nitrogen, methane, and others) discharge. Their ascent from the depths of the 

 Earth's crust he figuratively called 'the breathing of the Earth'. V. I. Vernadskii 

 also noted the connection of these gases with faults, stressing that all the large 

 hehum pools (AmartUo, Texas, and others) were connected with the outflows 

 of 'tectonic gas streams : nitrogen, methane-nitrogen gases, and methane' [28]. 

 In some methane-nitrogen gas streams the concentrations of hehum exceed by 

 several thousand times those of helium in the atmosphere. The source of this 

 heUimi is the crystalline basement, where it gradually accumulates, due to the 

 decay of radioactive elements. 'Nitrogen', V. I. Vernadskii pointed out, 'unlike 

 oxygen, constantly enters the Earth's atmosphere from the deep sections of the 

 Earth's crust ... In many places, gas streams are known to consist of almost 

 pure nitrogen, always containing noble gases. Besides these emissions, nitrogen 

 in the shape of urmoticeable emanation, undoubtedly, continuously penetrates 

 everywhere into the Earth's crust, and into the biosphere' ([28] p. 226). He 

 ascribed the same deep origin to free hydrogen, which now, thanks to improved 



