86 p. N. KROPOTKIN 



petroleum- and gas-bearing district have shown, first of all, that the petroleum- 

 and gas-bearing sources descend vertically to great depths, down to the folded 

 basement, consisting of metamorphic or igneous rocks, and, secondly, that in 

 an overwhelming number of cases, the distribution of petroleum is not connected 

 with the distribution (in area) of sedimentary formations rich in organic matter 

 (such, for instance, as coal and bituminous shales). 



That the problem is of great importance is shown by the fact that in 1954 

 it was discussed at the Lvov conference dedicated to the problems of the origin 

 and migration of oil where two reports in favour of the inorganic origin hypo- 

 thesis were submitted [7-9, 11, 15]. Earlier still, in 1951, N. A. Kudryavtsev 

 had criticized the organic theory and put forward serious arguments in favour 

 of the inorganic origin of petroleum [10, 11]. In the United States, the inorganic 

 (cosmic) hypothesis was supported by Macdermott [12]. Moreover, such well 

 known specialists as Van Tuyl & Parker and Van Orstrand [13, 14] also pointed 

 out some facts confirming this theory. 



At the same time, the ideas connected with the organic hypothesis were de- 

 veloping in such a way, that they began to contradict one another (the hypo- 

 theses of V. A. Sokolov, V. A. Uspenskii, and others), none of them being 

 universally accepted. In our mind, these contradictions are not accidental and 

 reveal a profound crisis, or an impasse, into which the organic theor}' has come. 



SPACE DISTRIBUTION OF OIL AND GAS DEPOSITS 

 AND THEIR RELATION TO THE TECTONIC STRUCTURE 



Oil fields are usually found in the regions which possess natural gas deposits 

 (methane, with a certain amount of ethane and heavier hydrocarbons), some- 

 times in mixed oil and gas deposits, forming together definite oil and gas pro- 

 vinces (petroUferous provinces). Geological investigation of these districts shows 

 that both their general outline and the location of separate deposits of petroleum 

 and gas occurring in the above-mentioned provinces, are determined not by the 

 presence or absence of sedimentary rocks rich in biogenic organic substances 

 (for instance, coal, carbonaceous and bituminous shales), but by purely tectonic 

 factors, i.e. by dislocations of the strata in the Earth's crust. Frequently, the 

 localization of oil is determined by deep faults, cutting both the sedimentary 

 cover and the crystalline basement under it, consisting of granite and gneiss. 

 Such are the petroleum fields of Egypt along the faults of the Earth's crust 

 bordering the Red Sea graben, the large gas fields of eastern Brazil, and the 

 oil appearing in the Lake Baikal graben in Siberia and in the Lake Albert graben 

 in Africa. The connection with the deep faults and flexures of the crystalline 

 basement is manifested, although in a somewhat masked form, in the location 

 of many oil and gas fields on tectonic platforms, for instance, the Volga River 

 fields, connected with the flexure of the Zhiguly Hills, in Eldorado field (Kansas, 

 U.S.A.) and others. (See Fig. i); [15-17]. This connection with the tectonic 

 disturbances indicates the compliance of the oil and gas deposits to the zones 

 where, owing to faults, flexures and tension of Earth's crust, the basement 

 becomes more penetrable to fluids rising from the depths of the Earth. 



