What is continental drift?

Answer 1

Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912. However, it was not until the development of the theory of plate tectonics in the 1960s, that a sufficient geological explanation of that movement was found.

Continental drift referred to the concept that the Earth's continents were once part of a large supercontinent and had subsequently split apart and arrived at their present destinations.

Continental drift theory has been replaced by the science of plate tectonics, an all inclusive explanation of the process of continent movements, crust creation, lithologies, subduction, the rock cycle, and so on. The engine behind plate tectonics is heat from the interior of the Earth. This heat is a combination of heat from radioactive decay, remnant heat from Earth's formation process, and crushing pressures from its mass.

Heat rises through the mantle outward toward Earth's surface. In a layer of the upper mantle known as the asthenosphere, the solid rock is plastic-like, enough so that the rock slowly flows in a current. The current rises to reach its maximum height at a weakness in the hard uppermost mantle with attached crust known as the lithosphere. At these points, the hot mantle rocks melt from the lowering of lithostatic pressure and rises to form new crust at the mid-ocean ridges. As new material is added at the ridges, the tectonic plates on either side move apart. Over time this causes the continents located on the plates to "drift' apart.

At the other end of the current, older, denser crust is being pushed under less dense crustal plates and less dense oceanic plates, in a downward trajectory toward the mantle, where it melts and gradually becomes part of the mantle rock once again. The Pacific Ocean is gradually shrinking due to the subduction of its boundaries in an area known as the Ring of Fire. One day it will cease to exist, and once again there will exist a supercontinent.

Answer 2

The movement, formation, or re-formation of continents described by the theory of plate tectonics.