What do you understand by the theory of continental drift? Discuss the prominent evidences in its support.

Introduction

The theory of continental drift, proposed by Alfred Wegener in 1912, suggests that the Earth's continents were once joined together in a supercontinent called Pangaea and have since drifted apart to their current positions. This theory laid the foundation for modern plate tectonics.

Key Evidences Supporting Continental Drift

1. Fit of the Continents

• The coastlines of continents like South America and Africa fit together like pieces of a jigsaw puzzle.
• This suggests they were once part of a single landmass.

2. Fossil Evidence

• Identical fossils of species like Mesosaurus (a freshwater reptile) and Glossopteris (a plant) are found on continents now separated by oceans, such as South America, Africa, and Antarctica.
• This indicates these continents were once connected.

3. Geological Similarities

• Mountain ranges and rock formations of similar age and composition, such as the Appalachians in North America and the Caledonian mountains in Europe, align when continents are placed together.
• This points to a shared geological history.

4. Paleoclimatic Evidence

• Evidence of glacial deposits in tropical regions like India and Africa suggests these areas were once closer to the poles.
• Similarly, coal deposits in Antarctica indicate it was once located in a warmer, tropical zone.

5. Distribution of Living Species

• Certain species, such as flightless birds like ostriches in Africa and emus in Australia, are found on continents that are now widely separated, supporting the idea of a shared landmass in the past.

Value Addition Block — Key Evidences at a Glance

Conclusion

The theory of continental drift, supported by diverse evidences from geography, geology, and paleontology, revolutionized our understanding of Earth's dynamic nature. It paved the way for the development of the plate tectonics theory, which provides a more comprehensive explanation of continental movement.