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Geo-morphology: Plate Tectonics, continental drift theory, features, details

 Theories on the formation of continents, and Plate Tectonics 

Plate tectonics has proved as a convincing explanation than continental drift theory over the formation of the landmass to its present form today. Continental drift theory was introduced by Alfred Wegener in the year 1912 while plate tectonics was independently worked on by Mckenzie, Parker, and Morgan in 1967.

Continental Drift Theory
The Continental drift theory is based on the matching of the coastline of landmass(jigsaw fit) and states that the whole landmass was initially a single landmass named Pangaea and later on separated out to its present form.
Reason for this inference:
1.Matching of continents
2.Distribution of fossil
3.Tillite Deposit
4.Placer Deposit
5.Rock of same age across Ocean

Rejection of Continental drift Theory
The cause of the movement of continents was attributed to 2 forces namely 
1.Pole Fleeing Force
2.Tidal force.

Plate Tectonics
The theory of plate tectonics divides the earth into 7 major and minor plates and states that all geophysical process are the result of plate interaction and the plates are in constant motion while the continents are stationary

Evidence in support of the theory
1.continental drift theory
2.Sea floor mapping
These two theories focused on the ocean than on land as done by Wegener. This observation gave stronghold to the theory on ocean floor spreading.
The theory stated that plates move due to a weak asthenosphere that is below the lithosphere and can cause the plates to move. Also, the paleomagnetic data proved the ocean floor is less mature pointing out that ocean floor has been subject to volcanic eruptions leading to the formation of mid-ocean ridges etc. which can lead to an expansion of the ocean bed


 

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