Q19A. What do you understand by the theory of continental drift? Discuss the prominent evidence in its support.

Model Answer:

Introduction

The theory of continental drift, proposed by Alfred Wegener in 1912, suggests that continents were once part of a single landmass and have since drifted apart. This concept revolutionized geological sciences by providing a mechanism for understanding Earth's changing landscapes and geological formations.

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Prominent Idea of the Theory

The central idea of continental drift is that the Earth's continents were once joined as a supercontinent called Pangaea, which began breaking apart approximately 200 million years ago. This gradual movement continues today due to tectonic processes. The continents' positions have shifted over time, resulting in the geographical distribution observed today.

Evidence Supporting the Theory

1. Fossil Correlation: Similar fossils of plants and animals are found on different continents, indicating they were once connected, like the Mesosaurus found in South America and Africa.
2. Geological Similarities: Mountain ranges and rock formations, such as the Appalachian Mountains in North America and the Caledonian Mountains in Scotland, share similar geological features and age.
3. Paleoclimate Evidence: Evidence of past climates, such as glacial deposits in present-day warm regions, suggests continents were once located in different climatic zones.
4. Fit of Continents: The jigsaw puzzle-like fit of continents, particularly the edges of South America and Africa, provides visual support for their historical connection.
5. Distribution of Earthquakes and Volcanoes: The patterns of earthquakes and volcanic activity correspond to tectonic plate boundaries, supporting the notion of moving continents over geological time.

Conclusion

The theory of continental drift laid the groundwork for plate tectonics, enhancing our understanding of Earth's dynamic nature. Evidence from fossils, geology, paleoclimate, continent shapes, and tectonic activity supports the idea of moving landmasses. This theory remains fundamental in geology, helping explain the planet's past and its ongoing transformations.

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