Answer» Correct Answer - Option 4 : A-II, B-III, C-IV, D-I
Theories | Proponents | Thermal Contraction Theory | - Jeffrey’s theory is based essentially on the history of the contraction of the earth.
- According to Jeffreys, the earth began to shrink because of contraction caused by gradual cooling of the earth due to loss of heat through radiation from the very beginning of its origin. He has mathematically calculated the extent of contraction on cooling.
| Theory of Geosyncline | - Geosyncline, a linear trough of subsidence of the Earth’s crust within which vast amounts of sediment accumulate.
- The filling of a geosyncline with thousands or tens of thousands of feet of sediment is accompanied in the late stages of deposition by folding, crumpling, and faulting of the deposits.
- It is given by Hall and Dana
| Theory of Seafloor spreading | - Seafloor spreading, the theory that oceanic crust forms along submarine mountain zones, known collectively as the mid-ocean ridge system, and spreads out laterally away from them.
- It was proposed by the American geophysicist Harry H. Hess in 1960.
| Doctrine of Uniformatarianism | - The principle of uniformitarianism is essential to understanding Earth’s history.
- However, prior to 1830, uniformitarianism was not the prevailing theory. Until that time, scientists subscribed to the idea of catastrophism.
- Catastrophism suggested the features seen on the surface of Earth, such as mountains, were formed by large, abrupt changes—or catastrophes. When discussing past climates, opponents to uniformitarianism may speak of no-analog changes. This idea suggests by James Hutton.
|
|
