Continental drift theory

If you look at the outlines of the continents in the Atlantic and Indian Oceans, you can see that the protrusions of some quite accurately correspond to the concave sections of others. It is not difficult to find, for example, overlapping sections of the Somali-Kenyan mainland with the protruding northwestern part of Australia. This was also noticed by the German geophysicist A. Wegener (1880-1930). He developed the so-called continental drift theory. Its essence was as follows: the continents that define the face of our planet were once a single whole, and then, under the influence of centrifugal forces, they parted to the sides. A. Wegener called it continental drift.

This was also noticed by the German geophysicist A. Wegener (1880-1930). He developed the so-called сontinental drift theory

Indeed, if you first cut out the continents from a geographical map and then bring them closer to each other, then it is not difficult to find their position in which a comparison with a broken plate arises.

A more thorough analysis, if you combine the contours along the modern coastline, reveals a lot of overlays, gaps and mismatches. After all, the coast does not mean the edge of the continent, but only the border of land and sea, moving in time. But, if we combine the contours of the continents along the edge of the shelf, as A. Wegener did, then we can achieve their more complete coincidence.

At the beginning of the century, research in the seas and oceans was just unfolding, therefore, A. Wegener's constructions were generally perceived as speculative. In those years, it was impossible to prove the legality of such combinations. Only today has the problem been satisfactorily solved. It turned out that the best coincidence of the contours of the continents located in the Atlantic and Indian Ocean can be achieved using their outlines along the isobath - 2000 m, i.e., already at depths corresponding to the middle part of the continental slope.

To prove the continental drift after the split of the giant supercontinent named Pangea by A. Wegener (Pangea consisted of two large continental conglomerates - Laurasia and Gondwana), he drew attention to the closeness of the age and composition of sedimentary and magmatic formations that compose the peripheral regions of Africa and South America from the side Atlantic Ocean. Another convincing argument in favor of the existence at the end of the Paleozoic - the beginning of the Mesozoic of a single continent in the southern hemisphere - Gondwana - was the traces of extensive continental glaciation found in southern Africa, South America, and the Indian subcontinent in Australia.

According to A. Wegener himself, the idea of a possible continental drift was prompted by data on the similar composition of paleontological remains. Especially striking were the finds on these continents of skeletons of Listosaurs - representatives of a rare group of dinosaurs. All this testified to the existence of a land bridge between the continents.

A. Wegener's intuition outstripped the development of science by almost half a century. The boldness and internal logic of the continental drift theory initially captured the minds of many of his contemporaries. But several years later, calculations were made, which showed that the mechanism of a possible continental drift in the form in which it was presented to A. Wegener is unrealistic. To move, boulders of enormous thickness and size had to overcome the resistance of the heavy and viscous oceanic crust, as well as the hard mantle, which at that time was difficult to explain.

After several years of excitement around A. Wegener's theory of continental drift, its popularity quickly declined. Various fantastic ideas, inspired by the theory of continental drift, also played a negative role. We find their echoes, for example, in A.N. Tolstoy's "The Hyperboloid of Engineer Garin".

In reality, the ocean remained almost as inaccessible to researchers as before. Little new facts emerged, and interest in the theory of continental drift gradually faded away. However, she managed to induce geologists to study the seas and oceans and gave impetus to the development of remote sensing methods.