The theory of continental drift posits that Earth’s continents were once joined together as a single supercontinent, Pangaea, and have since drifted apart over geological time due to the movement of tectonic plates. This revolutionary idea, proposed by Alfred Wegener in the early 20th century, was initially met with skepticism but has since become widely accepted. Evidence supporting continental drift includes the fitting together of continents like puzzle pieces, matching geological formations and fossil evidence across continents separated by vast oceans, similarities in rock formations and mountain ranges, and the distribution of ancient climates and species. These lines of evidence provide compelling support for the theory of continental drift, revolutionizing our understanding of Earth’s geological history.
Tags: Salient Features of World’s physical geography – Geomorphology.
Decoding the Question:
- In Introduction, try to start the answer with the background of continental drift theory.
- In Body,
- Discuss postulations of continental drift theory.
- Discuss the prominent evidence in the support of the theory.
- Conclude with mentioning its importance in leading to geomorphology.
Answer:
Continental drift theory deals with the distribution of the oceans and the continents. It was first suggested by a German meteorologist, Alfred Wegener in 1912.
Theory of ‘Continental Drift’:
- According to Wegener, all the continents formed a single continental mass, and the mega ocean surrounded the same. The supercontinent was named Pangaea, the mega-ocean was called Panthalassa.
- He argued that the supercontinent, Pangaea, began to split around 200 million years ago. Pangaea firstly broke into two large continental masses as Laurasia and Gondwanaland creating the northern and southern components, respectively.
- Eventually, Laurasia and Gondwanaland continued to break into various smaller continents as it can be seen today. The Tethys Ocean existed between the continents of Gondwanaland and Laurasia.
Evidence that supports the theory:
- The Matching of Continents (Jig-Saw-Fit): The shorelines of Africa and South America facing each other match remarkably.
- Rocks of Same Age Across the Oceans: radiometric dating methods have correlated the rock formation in different continents.
- Tillite: The glacial tillite found in the Gondwana system of sediments has its resemblance to six different landmasses of the Southern Hemisphere. Counterparts of this succession are found in Africa, Falkland Island, Madagascar, Antarctica and Australia besides India.
- Placer Deposits: The placer deposits of gold in the Ghana coast do not have source rock in the region. The gold deposits of Ghana have been derived from the Brazil plateau when the two continents lay side by side
- Distribution of Fossils: identical species of plants and animals adapted to living on land or in freshwater are found on either side of the marine barriers. For example, remains of Mesosaurus, a freshwater crocodile-like reptile that lived during the early Permian (between 286 and 258 million years ago), are found solely in Southern Africa and Eastern South America.
Continental drift theory may be outdated and was not approved by recent geological scientists. But it is true that continental drift theory is the pillar stone of geomorphology.
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