Which of the following are the evidences of the phenomenon of continental drift?

1. The belt of ancient rocks from Brazil coast matches with those from Western Africa.
2. The gold deposits of Ghana are derived from the Brazil plateau when the two continents lay side by side.
3. The Gondwana system of sediments from India is known to have its counterparts in six different landmasses of the Southern Hemisphere.

Select the correct answer using the code given below:

1. I and III only
2. I and II only
3. I, II and III
4. II and III only

Explanation

All are correct

• A German geophysicist named Alfred Wegener suggested Continental Drift Theory (CDT) in 1912. According to CDT, there existed one big landmass called Pangaea, which was covered by one big ocean called Panthalassa. A sea called Tethys divided Pangaea into two huge landmasses: Laurentia (Laurasia) to the north and Gondwanaland to the south of Tethys. Drift started around 200 million years ago (Mesozoic Era →Triassic Period → Late Triassic Epoch), and the continents began to break up and drift away from one another.
• Evidence in Support of the Continental Drift:
  • Rocks of Same Age Across the Oceans: The belt of ancient rocks of 2,000 million years from the Brazilian coast matches those from western Africa. The earliest marine deposits along the coasts of South America and Africa are Jurassic in age. This suggests that the ocean did not exist prior to that time.
  • Tillite: It is the sedimentary rock formed out of deposits of glaciers. The Gondwana sediment system from India is known to have counterparts in six different landmasses of the Southern Hemisphere. At the base, the system has thick tillite, indicating extensive and prolonged glaciation. Counterparts of this succession are found in Africa, the Falkland Islands, Madagascar, Antarctica and Australia. The overall resemblance of the Gondwana-type sediments clearly demonstrates that these landmasses had remarkably similar histories. The glacial tillite provides unambiguous evidence of palaeoclimates and also of the drifting of continents.
  • The Matching of Continents (Jig-Saw-Fit): The shorelines of Africa and South America facing each other have a remarkable and unmistakable match.
  • Placer Deposits: The occurrence of rich placer deposits of gold on the Ghana coast and the absolute absence of source rock in the region is an amazing fact. The gold-bearing veins are in Brazil, and it is obvious that Ghana’s gold deposits derive from the Brazilian plateau when the two continents lay side by side.
  • Distribution of Fossils: The presence of identical land or freshwater species across marine barriers, like lemurs in India, Madagascar, and Africa, led to theories such as the lost landmass ‘Lemuria.’ Similarly, Mesosaurus fossils found only in South Africa and Brazil—now 4,800 km apart—pose questions about past continental connections.

Answer: (c) I, II and III; Difficulty Level: Easy