Wegener supposed that several continental masses were assembled more closely in the late Paleozoic era. This super continent was called by him as ‘Pangaea’ (meaning all earth). The southern block consisting of Antarctica, Australia, Peninsular India, Africa and South America is known as Gondwanaland.
The northern block of Pangaea comprised North America, Greenland, Europe, north of the Indian subcontinent, and the remaining part of Asia, and it was known as ‘Laurasia’. These two major blocks were separated by a long shallow belt of sea called the ‘Tethys’.
Pangaea was surrounded on all sides by the mega-ocean called ‘Panthalassa’ (meaning all water). The Panthalassa may be considered the primeval Pacific Ocean. Wegener presumed that in the Carboniferous period the South Pole was near Natal, South African coast, and the North Pole was in the Pacific Ocean.
In the theory of continental drift, Wegener was convinced about the polar wandering. In other words, there was a considerable shift in the position of the geographical poles.
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However, it is not known whether the continental drift and the polar wandering occurred in succession or simultaneously. So far palaeomagnetic evidence is not so definite as to answer this question.
Soon after the close of the Palaeozoic period Gondwanaland began to break up into huge crystal blocks which glided slowly over the substratum of sima, and changed their positions and relative locations with reference to the North and South poles.
The forces involved to cause the drift, according to Wegener, were differential gravitational forces as well as the tidal force exerted by the sun and the moon.
One of these forces caused a drift towards the equator, while another force caused the general westward drift. The gravitational and rotational forces were responsible for the northward drift, while the westward drift was caused by the tidal forces.
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It was presumed that the African and European land blocks moved together under the influence of the gravitational force; while North and South America drifted westward in response to the tidal force of the sun and the moon.
As North and South America moved towards the west against the resistance of the Pacific floor, their front edge would be crumpled up into great mountain ranges. Between these two continental land masses, certain parts of the sial lagged and formed the islands of the West Indies.
The supposed effects of the Westerly drift of Asia resulted in the formation of gaping fissures on the Pacific floor. The island festoons are supposed to have been strips of sial that remained attached to the main land at their ends.
However, the flights from the two poles and westerly drift by the tidal force have been disproved by the scientists as completely impossible.
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“The present distribution of the continents was regarded as a result of fragmentation by rifting followed by a drifting apart of the individual land masses.
The southern continents began to unfold during the Mesozoic era by being dragged away from wherever the South Pole happened to be at any given time during the progress of the outward movements”. Arthur Holmes.
The Atlantic Ocean is probably the immense gap left behind. By the time the continents had reached their present positions Antarctica found itself alone over the South Pole.
Even though the concept of polar wandering could not get the approval of the geologists and geophysicist, with the promulgation of the concept of plate tectonics and ocean floor spreading the geophysicists have been won over by the testimony of palaeomagnetism.