1961 cont.

The Geological History of Atlantis, By N. Th. Zhirov (Doctor of Chemical Sciences, Moscow, USSR) (Trans. by Mrs. E. Cordasco)

"How can the origin and the geological history of Atlantis be regarded as that of an extensive land area which existed not very long ago somewhere in the North Atlantic? It must be agreed first, that our discussion will not make use of the paleo-geographic schemes elaborated not long since (for example, by T. Ardt or H. Ihering) because they are all extremely hypothetical as to the oceans, and insufficiently supported by data on oceanology and oceanic geology, data not available when these works were written. Therefore, building one's own hypothesis on the basis of another hypothesis does not make sense.

First of all, we postulate two basic premises, namely, that a more or less extensive area of dry land could have been connected only with the North Atlantic submarine ridge, and secondly, that it could not be earlier than the pre-Cambrian plateau. The first premise is borne out by the study of the topographic peculiarities of the North Atlantic ocean bottom, and the second by all the geological and seismic data now available concerning this part of the globe. In general, there are two basic variances for locating Atlantis in the North Atlantic, of which the first might be called the Azorian, because in this version the basic massif is related to the continent of Europe, and is orientated in the region of the Azores and the North Atlantic Ridge. In the second version, the Canarian, Atlantis is located near the coast of Africa, on the basis of the Canary Islands. This version is very popular, especially among the French Atlantologists. Its popularity is founded on the fact that of all the islands of Macronesia, only the Canaries had an autochthonous population of unknown origin. Among Soviet atlantologists, an ardent supporter of this version was B. L. Bogaevsky. The Azorian version, however, would appear to be sounder, geologically and bathymetrically. A whole series of weighty arguments in its favour was put forward on 30 November 1955, by the Late E. F. Hagemeister at the meeting of the natural history research association of the Estonian Academy of Sciences. It indicated a series of details from Plato's account, which tallied with the Azorian version, and did not agree with the Canarian one. The present writer supports the Azorian version, and will consider the history of Atlantis from this point of view.

Let us examine only the geological history of Atlantis from the moment of its formation, which a combination of all the data places in the Cainozoic period. Earlier stages belong to the history of the Atlantic Ocean as a whole, and are obscure and still insufficiently known. The difficulty of study is aggravated by the circumstances of subsequent fusion's occurring in the ocean bottom, the flow of enormous masses of basalt, the complex tectonic movements, all combining to obscure the picture. Nevertheless, it is evident that there are many reasons for assuming that before the Cainozoic, there could have been no question of an ocean, i.e. of the existence of basins of great depth in the region covered by the Atlantic at the present time. Although the areas covered then by the sea could have been very great and might have extended beyond the limits of the present Atlantic, these were shallow waters. The formation of the deep ocean basins, as the writer noted in his preceding article, is characteristic of the later stages in the geological history of the earth. It began, evidently, only in the Cainozoic, in connection with the general increase of contrast between land and sea, and is probably in definite connection with alpine orogenesis. If Atlantis is considered as a small continent and not as an island, and there are reasons for this belief, then it must be recognized as one of the youngest continents on this earth, and of a formation entirely different from that of the "Old" continents. The practical absence of sialytic (granite) materials and the obviously basalt nature of the North Atlantic ridge indicate that the formation of this mountain range and of its adjacent land areas was caused by early tectonic processes which occurred at a time when these regions no longer contained sufficient quantities of granite, and were being subjected to assimilation and basalt fusion. Thus all the processes of mountain formation were carried out almost exclusively with materials derived from the deeper layers, the basalts. Let us not discuss the question of the thickness of the original sialytic layer in the region of the present Atlantic Ocean prior to its re-fusion and assimilation, and before the formation of the Central Atlantic ridge, nor of what was the nature of this layer, whether it was purely of granite or of anything else. Unfortunately, for this purpose, necessary data is lacking. Only on the basis of the most general considerations can it be assumed that this thickness was not great and that, except for the most northerly parts of the Atlantic, it was much less than that of the sialytic layer of neighboring continents. Simultaneously with the formation of the Central Atlantic ridge and ocean deeps, this layer was fused and assimilated by basaltic magma, which replaced it completely in very many places. Moreover, there are important reasons for presuming that there is an essential difference between the North and South Atlantic, i.e. in the history of its two ridges. If such an expression is permissible, then the North Atlantic ridge is the basic "core" of Atlantis. What then, after all, can be said about the nature and origin of this ridge on the basis of the meager facts at our disposal? There have been hypotheses concerning the origin of the Central Atlantic ridge. In 1900, E. Haug considered that it was the central anticlinal. In 1910, F. B. Taylor regarded it as a fold. In 1924, A. Wegener thought it was the bottom of a crack which widened before the separation and drift of adjacent continents. In 1928, G.A.F. Molengraaff was really of the same opinion. In 1930, H.S. Washington deduced from the data on the ultra basic nature of the rocks of St.Paul and the unmistakable evidence of great pressures occurring at the metamorphosis of the peridotite of these rocks, that the ridge was subjected to powerful lateral pressures during its formation. From this conclusion, he favored the hypothesis of different torsion in the two hemispheres, and considered that this hypothesis would help to explain not only the predominate direction of the ridge, but also its equatorial bend. In 1940, W.H. Bucher drew attention to the essential similarity in form of the continental and oceanic structures of the North Atlantic and its surrounding regions. He considered that the forms of the ocean bottom appeared to be comparable with the basins and heights of continental regions beyond the limits of the orogenetic belt, although the scale for oceanic surfaces was greater, both horizontally and vertically. In 1947, J.H.F. Umbgrove laid emphasis on the symmetrical distribution of deeps and ridges in the south Atlantic and on the African continent, and thought that the predominant directions here are undoubtedly similar to linear types of the earth's crust (North-South, West-East). In 1939, H. Cloos on the basis of experiments with a clay model, demonstrated that the topography characteristic of the Azores plateau can be explained by cracks in the earth's crust producing a series of fractures parallel with the longer global section (N-W, S-E), resulting in the extrusion of magma through these cracks corresponding with the NW-SE direction of the ridges discovered by the "Altair" expedition. Consequently, some force directed upwards from below caused a swelling of the earth's crust in the region of the Azores Islands, which resulted in the formation of cracks and extrusion of magma. Therefore, the Azores are not product of crease formations connected, as generally believed, with lateral pressure and kneading together of upper and lower strata into folds. Somewhat earlier, J. Agostinho, in 1936, also believed that the main topographical peculiarities of the Azores plateau were caused by volcanic eruption through clefts, chiefly in the NW-SE direction. He connected the formation of this large protuberance with the fact that it is located at the intersection of the two main submarine tectonic trends: that nearly N. to S. for the North Atlantic ridge, and that nearly W. to E. formed in succession to the heights and banks, beginning with the Grand Banks of Newfoundland through the Milne Bank, the Azores Islands, and the banks West of Gibraltar. I. Tolstoy writes that if the structure of the Azores plateau is due to the superimposition of two separate structural processes, then the mechanics of the formation of several ridges on this plateau, suggested by H. Cloos, must be re-examined. The structure of a series of the Azores Islands is not analogous to that of the North Atlantic ridge and, probably, is really due to the combined effect of superimposition of at least two great structural occurrences. Therefore, all that is said about this region cannot also be applied to the North Atlantic ridge. This would include Iceland, whose structure is the product of a split block, accompanied by a huge flow of lava. Iceland is also located at the intersection of the North Atlantic ridge with a traverse bend, frequently regarded as the Caledonian fold. The great cleft, connected with the central Icelandic trench, also nearly corresponds with the NE-SW direction, parallel to the direction of the North Atlantic ridge to the southwest of Iceland.

The Geological History of Atlantis, By Dr. N. Th. Zhirov (continues) 1961 cont.

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