Answer the following questions in about 30 words.
(i) What were the forces suggested by Wegener for the movement of the continents?
(ii) How are the convectional currents in the mantle initiated and maintained?
(iii) What is the major difference between the transform boundary and the convergent or divergent boundaries of plates?
(iv) What was the location of the Indian landmass during the formation of the Deccan Traps?
(i) There were two types of forces as suggested by Wegener for the movements of the continents.
• Polar feeling force- It relates to the rotation of the earth. The Earth has a bulge at the equator due to his rotation of the Earth.
• Tidal force- It is the force developed due to the attractive pull by the Sun and the Moon which develop tides in ocean water.
Wegener believed that these two forces would continue for millions of years.
(ii) The conventional currents are generated due to presence of a radioactive element causing thermal differences in the mantle portion. That is the hot material rises up and the cold thing sinks down. Holmes said that these forces were present throughout the mantle.
(iii) Transform Boundary- When the crust is neither destroyed nor produced as the plates slide horizontally past each other. Then it is called transform boundary.
Convergent Boundary- When the crust is destroyed as one plate dived under another, then it is called convergent boundary
Divergent Boundary- When new crust is generated as the plates pull away from each other, then it is called divergent boundary.
(iv) When the Indian plate moved towards the Eurasian plate, the outpouring of lava and the formation of Deccan Traps took place. This started 60 million of years ago and continued for a long time and the subcontinent was still close towards the equator.