Continental Drift Theory

Published on 31 Jan 2025

Put forward by Alfred Wegener in 1912. According to Wegener, there existed a super continent called Pangea which is surrounded by Super Ocean called Panthalassa. 200 million years ago Pangea split into Laurasia and Gondwanaland forming northern and southern components respectively and was separated by Tethys Sea. Later, Laurasia and Gondwanaland subsequently broke into smaller continents that exists today.

Evidence in support of continental drift theory 

• Jigsaw fit matching continents: Matching shorelines of continents in jigsaw fit. 

• Example: Shorelines of Africa and South America facing each other showing a remarkable match. 

• Rocks of same age across oceans: Belt of ancient rock from Brazil matches with West Africa.

• Example: Appalachians seems to continue through New Found land into Green Land and Pennines.   

• Marine deposits and tillite of similar age across continents: Tillites are the sedimentary rocks formed out of deposits of glaciers. 

• Example: Gondwana system sediments from India have counter parts from south hemisphere like Africa, Madagascar, and Australia etc.   

• Placer deposits: Placer deposits are concentrations of heavy minerals like gold and diamonds, formed by erosion, transportation, and sedimentation processes. 

• Example: Occurrence of rich placer deposits of gold in Ghana without any source rock and presence of gold bearing veins in Brazil. 

• Distribution of fossils: Fossils of similar species and plants are found on continents that are now separated by oceans.  

• Example: Fossils of shallow brackish water reptile Mesosaurus found in southern Cape Province of South Africa and from Iravar formations of Brazil.

• Paleo climatic evidence: Mismatched past climate evidence, including coal beds and glacial deposits, implies continents had different positions.

• Example: Many of the tropical areas such as Durban in South Africa (glacial till) & Talcher (glacial striations) in India have evidences of glacial processes. 

Limitations of continental drift theory 

• Force for drifting: Polar fleeing force and tidal force suggested by Wegener are too small to move continents.

• Failure in explaining other geomorphic structures: Like mountains, rift valleys etc. 

• Focussed only on surface phenomena: Thus failed to explain the process occurring in the interior of earth.  

Still his theory promoted further study regarding formation of continents and became the basis for present day’s Plate tectonics theory. 

Tags:
Geography

Keywords:
Continental Drift Theory pangea Panthalassa Laurasia Gondwanaland tethys sea Evidence in support of continental drift theory jig saw fit Limitations of continental drift theory

Syllabus:
General Studies Paper 1

Topics:
Physical Geography