HOME	Tectonic Processes: Continental Drift The Island of Newfoundland, along with its surrounding seabed, is the product of the slow collision and separation, over hundreds of millions of years, of massive sections of the Earth's crust and solid outer mantle - known as "tectonic plates" - which "float" upon the denser, fluid, inner mantle below. The movement of tectonic plates - called "continental drift" - is powered by massive, slow-moving, mantle currents produced by the heat of extreme pressure and radioactive decay within the Earth. Where tectonic plates are forced together, the enormous stresses on the Earth's crust and solid outer mantle result in earthquakes, volcanoes, and often, significant vertical crustal movement. Where the edges of the plates are pushed upwards, or simply crumpled, mountain ranges are the normal result. Where the edges of the plates are forced downward, deep ocean trenches are often formed. Where plates are pulled apart, molten volcanic material flows upwards, and cools, to form widening ridges along the fault. In the process of all of this commotion, ancient seabeds were often pushed upwards, coming to rest, at least for a time, above the level of the waves [PAGE UNDER CONSTRUCTION]