ABSTRACT
The paper is an attempt to reconcile two apparently contradictory theories regarding the distribution of oceans and continents on the earth’s surface, namely, the Tetrahedral theory and Wegener’s hypothesis. Each of these theories accounts eminently satisfactorily for a large series of important objective facts; but, by itself, fails to explain another series of equally important facts inherent in the other.
The Tetrahedral theory has a sound mathematical and physical basis. The antipodal distribution of lands and oceans on the earth at present is in such close agreement with the positions demanded by theory that the “fit” can not be disregarded and looked upon as entirely fortuitous. Yet there are outstanding anomalies such as the overlap of Patagonia and China in an antipodal map, and the position of the northern continents with an average latitude of 45° N. Such discrepancies must be explained if possible.
Wegener’s hypothesis accounts for so many undisputed facts in connection with geology, paleontology, and climate, otherwise absolutely incredible, that its main thesis of continental drift must be accepted, at least as far as the southern continents and India are concerned. The glacial features of Gondwana land, the distribution of the Glossopteris-Gangamopteris flora, and of the associated marine and land faunas of all the southern continents and of Peninsular India fit into the framework of a southern continent, with a center of ice distribution near Madagascar. No other suggestion can account for the objective facts involved. For South America, South Africa, India, Australia, and Antarctica to present the evidences of former close association which they unquestionably do, nothing but continental drift on a major scale can be visualized.
Reasons are given for suggesting that the outstanding anomalies may be eliminated, and the apparent paradoxes brought into complete harmony by assuming that, while the tetrahedroid tendency of a contracting and solidifying globe has played a very important part in earth history, its initial stages of development were interfered with and distorted by the early asymmetrical development of the Pacific Ocean basin, which is still a geographical element of abnormal character and dimensions. Whatever may be the ultimate cause of this gigantism of the Pacific Ocean, the fact is an objective one.
It is suggested that the theory put forward by G. H. Darwin, that the Pacific Ocean represents the scar left on the earth mass by tidal separation of the moon, be reexamined from a new angle. The bulk of the paper is devoted to an analysis of the results of such a phenomenon, which may, by analogy with physiological nomenclature, be termed a traumatic lesion of the earth body.
Reasons are given for supposing that such an injury, taking place some time after the earth had developed a permanent solid crust, could have caused “congenital deformity” of the embryonic tetrahedron, the development of which can be visualized as commencing some time after the initial formation of a solid crust. It is thought that the presence of the Pacific scar was responsible for the displacement of the Antarctic quoin of the tetrahedron toward South Africa, which is antipodal to the Pacific depression. The dihedral edges of the tetrahedron connected with this quoin were similarly twisted, leading to the development of the Gondwana continent.
Incidentally, it is suggested that there is no need to assume, as is done in Wegener’s hypothesis, that the center of ice distribution in Permo-Carboniferous time was the South Pole of the earth of that period. This assumption involves a number of serious paradoxes, and is not acceptable to astronomers and geophysicists.
It is thought that the traumatic lesion of the earth was more severe in the South Pacific than was the case in the North Pacific, and that the development of the northern continental masses in such high northern latitudes may be a consequence of this.
As cooling of the earth proceeded, and ever deeper zones of the earth’s interior ceased to alter their surface areas, the tetrahedroid tendency asserted itself in them. Such deeper zones were not controlled by the Pacific scar. As the tetrahedroid stresses accumulated they attained critical dimensions and carried the roots of the continental masses imbedded in the contracting zones nearer to the positions of ideal tetrahedroid symmetry. This gives a motive power for Wegenerian drift which is lacking in the original presentation.
Since accumulation and relief of stress are both gradual, a reason is provided for the periodicity of eras of orogeny. At the same time adequate amounts of kinetic energy, always a problem in dealing with the phenomena of diastrophism, are made available. Such effects are in no way exclusive of the results of radioactivity, sedimentation of geosynclines, internal flow of earth temperatures, and so on, but are complementary to them.
Reasons are adduced for believing that it was not until the initiation of Hercynian diastrophism that “dehiscence” of the Gondwana land knot occurred, initiating the rapid and extensive continental drift which has been shared by all the southern continents and Peninsular India.
The immediate effects of this drift are examined. It is shown that India has not yet reached its normal tetrahedral position between the Sino-Siberian shield and the Western Australian one, having been delayed by having had to plow through the enormously thick sediments of the great geosyncline of southwestern Asia, which geosyncline must be interpreted as the functional northerly extension of the Indian Ocean. In its later movements India has caused the crumpling of the greatest mass of fold mountains in the world.
South America, also, has not yet reached its allotted place in the tetrahedral symmetry, south of the Canadian shield. Had it done so, it would have become exactly antipodal to the Turkestan-Caspian region, which, as just mentioned, is functionally the northern end of the Indian Ocean.
A further suggestion is that when the Pacific was produced the ragged edges of the scar were left, and have persisted ever since as a circum-Pacific ring of earth structure. The possible effects of such a highly hypothetical structure are analyzed, and the suggestion is advanced that it may assist in explaining certain tectonic features such as the distribution and limitations of Laramide folding, and the remarkable loops and tectonic complexities encountered in the Caribbean, Moluccan, and Falkland Island regions.