Since the early 20th century, the Continental Drift Theory has been a subject of intense debate among geologists and scientists. Proposed by Alfred Wegener in 1912, this theory suggests that the Earth’s continents were once joined together in a single landmass called Pangaea and have since drifted apart over millions of years. While the theory has gained widespread acceptance today, it was met with skepticism and opposition in its early days. In this article, we will explore the arguments in favor of and against the Continental Drift Theory.
Continental Drift Theory
The continental drift theory was first proposed in Abraham Ortelius in 1596, however it was not fully developed, and therefore, failed to get widespread attention. In early 20th century, specifically said 1912, the famous German meteorologist, geophysicist, and polar researcher, Alfred Wegener proposed the Continental Drift theory. Alfred Wegener’s theory hold prominent grounds in explaining the formation and distribution of oceans and continents.
According to Alfred Wegener’s continental drift theory, around 350 million years ago, in carboniferous period, all the seven continents that we see today were actually only one land. That one land was the super continent called Pangea. Meanwhile in the same period, all the five oceans that we today, were actually only one mega ocean called Panthalassa. However, at the end of the carboniferous age, the super continent began to breakdown.
Around 250 million years ago, in the Jurassic period, the super continent breaks down into two parts called Gondwanaland and Laurasia, moreover the see lies between these two continents is termed as Tethys Sea. Later around 200-150 million years ago, in Paleogene period, the Laurasia continent was divided into three parts called North America, Eurasia and Asia, meanwhile, the Gondwana land divided into four parts called South America, Africa, Indian Peninsular, and Australia/ Antarctica. Later they continue to breakdown and forms several continents and oceans that exists today.
Arguments in Favor of Continental drift Theory
Alfred Wegener supported his hypothesis with multiple evidence such as, fits of continents, rock and mineral composition, flora and fauna and many more. These are discussed below…..
Jig-Saw-Fit (Fits of Continent)
Alfred Wegener supported his theory by the presenting multiple evidence related to the similarities and dissimilarities in the structure of landform and composition of rocks found on different continents. For example, the coastline of South America and Africa, facing each other, possess a unique boundary fit, potentially suggests that they have remarkable and unique boundary match. Another evidence he provides was the similarity between the composition of Patagonia desert and Angola highlands. His evidence was somewhat near to prove that once all the seven continents were the part of one super continent called Pangea.
Rocks approx. of same age
The age of rocks is determined via the radiometric method and carbon dating method. The similarities in the composition of rocks from two different sites, determines the fact that, oceans never existed before that time. Evidence like- The composition of rock belts of West Africa matches with the rock belts in Brazil. Moreover, the composition of rock belts in South America matches with the rock belts of Africa. The similarities in rock formations and mountain ranges on separate continents provide further evidence for continental drift.
The Appalachian Mountains in North America and the Caledonian Mountains in Europe, for example, share similar geological characteristics, suggesting they were once part of the same mountain range that has since been separated by the movement of continents.
Sediments of Gondwana Land
The Gondwana land which is now the Indian-Peninsular, was once the part of continents lies in southern hemisphere. Therefore, the glacial sediments of Gondwana, called tillite, are found in five southern regions. These are Madagascar, Africa, Antarctica, Falkland Island, and Australia. The similarity of the Gondwana sediments suggests that, these islands were once a single landmass and shares common origin.
Fossils of Reptiles
The fossils of lemurs were excavated from the sites of India, Africa and Madagascar. Potentially suggesting that these were once connected. Moreover, the Jurassic period Reptile, Mesoporous, is adapted to only the shallow brackish water, however its fossils are found in Brazil and South America.
Gold Deposits
The presence of gold deposits in the Ghana without any existence of its source rock is somewhat impossible to be true. Without a source rock, the mineral can’t be present. Actually, the source rock or mineral vein is present in Brazil plateau.
Arguments in against of Continental drift Theory
Although Alfred Wegener represented multiple evidence based on similarities and composition, potentially depicting the existence of only one major continent and major ocean. However, lacked on the explanation of one domain. That is, he was not able to explain why the continent breaks down. He present multiple theories to explain the breakdown of continent, nevertheless all were heavily criticized and rejected. His theories are discussed below…..
Gravitational Force by Sun & Moon
He proposed that, when sun, moon and earth, all align in single line, that is, the condition of solar eclipse, the gravitational of both sun and moon, pulled the continent and hence it breaks. Moreover, the moon used to be closer to earth, and therefore exerts more gravitational as compared to present day. However, this theory was heavily criticized, on that fact that, even moon was closer to earth, it will require million times force to lift or break the continental mass of earth.
Earth’s Rotation
Since earth’s shape is geoid, that means it’s bulged out from equatorial pole, the rotation speed of earth is more at equatorial plane than that of polar plane. Due to high rotational force, the continental mass breaks down. Nevertheless, this theory was rejected on the grounds of Coriolis force. The Coriolis force is that force which act opposite direction to the gravitational force, therefore, breakdown of continental landmass is impossible with this reason.
Way Forward
Despite the initial skepticism and opposition, the Continental Drift Theory has emerged as a fundamental concept in the field of geology. The arguments in favor of continental drift, including geological fit, fossil evidence, rock strata, paleoclimate data, and plate tectonics, provide a robust foundation for understanding the movement of Earth’s continents over time. While criticisms such as the lack of mechanism and insufficient time were raised in the past, advancements in scientific knowledge and technology have helped to address these concerns. Today, the overwhelming evidence supports the idea that our continents were once connected and have since drifted apart, shaping the world as we know it.
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