Prof. A. Wegener was a German meteorologist who proposed a hypothesis to explain the climate of the past. Prominent evidence shows that tropical regions of India, Brazil (South America), South Africa, and Australia were glaciated during the coal epoch.
This is only possible if we assume that in the past, the distribution of climate belts on the continents was different. Geologists proposed the existence of a vast continent and Wegener determined the idea of horizontal movement within the continental sim.
- Explain the meaning of Physical Geography. Explain its Scope and Importance.
- Explain the composition of the Earth’s Womb.
- Write the Main Hypotheses Related to the Origin of the Earth.
During the coal cycle, all continents were joined together. The name given to this combined land area was Pangea, while the rest of the earth was covered by a vast ocean called Panthalassa. Pangea was a small continental ocean horizontally. In the Proto-Great Age, Australia, Antarctica, the Indian peninsula, Africa, and South America were called the Gondwanaland of the southern group, while North America, Europe, and Asia were the land parts of the northern group, Laurasia. The Tethys sea was situated between the land parts of these two groups.
Wegener made it clear that the present continents were interconnected as one wide part. Additionally, he assumed that the South Pole was located near the southern coast of Africa, but the current distribution of continents is due to the breakup and displacement of Pangea. Wegener said that the continents were shifted in two directions due to displacement force, one due to the effect of the difference in gravity, the continental displacement towards the equator, and the other due west due to tidal force.
Thus, it is observed that the land part of Africa and the European group was displaced by the influence of the first power, resulting in the distribution of land and water parts seen on the earth’s surface in the present era. Furthermore, Wegener tried to show which part of Pangea broke apart under his continental displacement hypothesis, with the first form being the Coal Age, the second form being the Adi New Age, and the third form being the fourth Mahakalpa.
Fundamentals of the Hypothesis
- Despite the difficulties in explaining westward and equatorial continental displacement under this hypothesis, F.V. Taylor estimated this type of continental displacement before Wegener. Taylor accepted Wegener’s idea of displacement from the two poles to the outward and radial motion, which led to the formation of many mountains and islands in the Northern Hemisphere. The French scholar Snyder also made the same suggestion.
- In the years following Wegener’s proposal, many supporters have presented evidence in favor of continental displacement, proving the horizontal movement of the Earth’s crust. According to current ideas, the formation of mountains requires a movement of hundreds of kilometers. Thus, the formation of mountains may have contributed to continental displacement, making Wegener’s idea of displacement seem plausible.
- Although Wegener was an astronomer, he presented much evidence regarding continental displacement from geophysics, geology, etc., which is based on the following:
- There is a resemblance between the coasts of the North and South Atlantic Oceans. According to the “Jigsaw fit” principle, North America and Greenland are linked to Europe and the east of South America. The eastern coast is well connected with the western coast of Africa.
- The surface structure of both coasts of the Atlantic Ocean is similar. The mountains of Western Europe and the Appalachian Mountains of North America are known to have formed at the same time. The Arabian plateau, the southern Indian plateau, and the western Australian plateau are known to be composed of hard rocks of the same age.
- Fossils of ancient flora and fauna found on either side of the Atlantic Ocean are similar to each other. Coal rocks found in both parts are similar, with coal mines present. The same type of coal is found in Western Europe, the British Isles, and the Appalachian regions of North America. The vegetation sequence from the northern rocks also shows similarities. Dutoit explained these similarities.
Criticisms by Scholars
Opponents of the hypothesis have presented the following points:
- The hypothesis does not explain any force that could cause displacement in continents. Wegener argued that tidal forces cause the westward displacement of continents. However, it would require a force that is 10,000,000,000 times stronger than the current power to move continents, and this force would have completely stopped the Earth’s rotation within a year.
- The equatorial force cited by Wegener is also incapable of continent displacement. If such a force existed, the continents would have gathered near the equator. However, Holmes explained that another force was acting opposite to the displacement force, preventing the continents from converging at the equator.
- Another issue with Wegener’s hypothesis is that the continental part he considered to be made of Siel cannot flow on Simai. According to Willis, Simai is more rigid than Siel. Bobby also argued that Siel is more powerful than Sim, so it cannot make a turn by swimming on it.
- Geologists who oppose Wegener’s hypothesis argue that according to the “Jigsaw Fit” theory, Africa and South America fit together, and Australia and New Zealand fit in the Arabian Sea. However, the oceanic parts of West Greenland and Bayfinland do not fit anywhere between them.
Views of Four Scientists on the Origin of Continents and Ocean Floor
Lapworth, Jeans, Daly, Jolie, Wegener, and Arthur Holmes have different views regarding the process of the origin of continents and oceans.
According to Lapworth, the compression and folding of the earth’s surface caused large-scale compression and folding. As a result, continents and oceans were formed.
Jaffray proposed the thermal contraction hypothesis and suggested that the contraction of the Earth and the decrease in its rotational speed helped in the origin of the continents and oceans.
According to Daly, there was a continent on Earth, Pangea, and the ocean Panthalassa. But due to the excess of gravity, the continents got fragmented, and the oceans formed between the broken fragments. He named this theory the continental drift hypothesis.
In Wegener’s hypothesis, the current arrangement of different continents and oceans is due to the dislocation and break-up of the old Pangea continent.
Holmes’s convection current hypothesis is based on radioactivity. This is a more established hypothesis. According to this, where the currents rising above and below the continent separate from each other, the continent becomes thin and breaks up. The long Sacred Sea is born. In this, the depressions of the continents accumulate and then become concave and give birth to mountains. During the formation of mountains, the terrains move away from each other and then come closer. In this way, the continents keep shifting, and this is possible by the convection current.