Continental Drift

This theory deals with movement of earth՚s continents relative to each other. This hypothesis stating movement of continents was first given by Abraham Ortelius in 1596. Alfred Wegener in 1912 fully gave this concept. Plate tectonics theory in 1960s gave good geological explanation of continental drift. Wegener postulated that a single “supercontinent” Pangaea existed in past and is in continuous motion to create present face of earth. Wegner elaborated concept in the book “Die Entstehung der Kontin…

… (90 more words, 1 figure) …

Subscribe (by clicking here) to view full notes and track progress.

Continental Drift: Basis of Evidence

Basis of Evidence

Wegener developed his idea based upon four different types of evidence:

• Jigsaw Fit of Continents: This amazing fit of continents gave rise to idea of continental drift. Abraham Ortelius, Theodor Christoph Lilienthal, Alexander von Humboldt, Antonio Snider-Pellegrini, and others pointed to the fact that shapes of continents on opposite sides of the Atlantic Ocean (mainly Africa and South America) fit together. In 1960՚s, it was recognized that continental fit was further improved by f…

… (386 more words, 14 figures) …

Subscribe (by clicking here) to view full notes and track progress.

Continental Drift: Premises and Mechanism of Continental Drift

Premises and Mechanism of Continental Drift

Wegener hypothesized Pangea (All-Earth) as original, gigantic supercontinent 200 million years ago, which was made of all of earth՚s landmasses surrounded by water body called Panthalassa. It existed from Permian through Jurassic periods and was made up of

• Laurasia included North America, Europe and Asia depicting northern part
• Gondwanaland included South America, Africa, Madagascar, Peninsular India, and Australia and Antarctica depicting southern part of Pa…

… (26 more words, 3 figures) …

Subscribe (by clicking here) to view full notes and track progress.

Continental Drift: Process of the Theory

Process of the Theory

• Forces Responsible for Drift: According to Wegner, Pangaea drifted in two directions because of
  • Equatorward Movement: It was caused by gravitational forces and forces of buoyancy. Lighter crust (SIAL) floated on the heavier material below (SIMA).
  • Westward Movement: This was caused by the tidal forces of sun and moon. This was at a maximum, when the moon was nearest to earth.
  • Centrifugal Pseudoforce: Pulling apart of continents by centrifugal pseudoforce of earth՚s rotation.
• Actual D…

… (330 more words, 6 figures) …

Subscribe (by clicking here) to view full notes and track progress.