Mesosaurus fossil, a reptile that lived in freshwater lakes and rivers that lived about 260 million years ago, was found in the South American continent and the African continent.Cynognathus fossil, a reptile that lived about 240 million years ago and was found in the South American continent and the African continent.The discovery of fossils from animals and plants are widespread and separated on several continents Based on the lack of compatibility shape of the coastline was then Wegener tried to match all the continents on earth. Wegener suspected that both continents were originally one. Both this coastline when matched to one another will coincide. The lack of compatibility coastline in the eastern part of the South American continent with a coastline of the western part of the African continent. Proof of the existence of the super-continent Pangaea 200 million years ago supported by the facts as follows: This super-continent Pangaea allegedly formed 200 million years ago which was then fragmented into pieces smaller then migrate or drifted into position as it is today. An effect of this floatation continent hypothesis is a hypothesis which assumes that the continents that exist today united formerly known as the super-continent called Pangaea. Actually, the theory of plate tectonics already emerged when the idea of the Flotation hypothesis Continent ( continental drift) was introduced first time by Alfred Wegener (1915) in his book 'The Origins of Oceans and Continents'. The revolution in the science of earth has been started since the early 19th century, when the emergence of a radical thought at that time to propose a hypothesis about the continents that move on the surface of the earth. Slab pull is thought to be at least twice as important as ridge push in moving an oceanic plate away from aridge crest.

The subduction plate may also increase its density while it sinks, as low-density materials such as water are lost and as plate minerals collapse into denser form during subduction. This density contrast is partly due to the fact that sinking lithosphere is cold.

A subduction plate sinks because it is denser than the surrounding mantle. Cold lithosphere sinking at a steep angle through hot mantle should pull the surface part of the plate away from the ridge crest and then down into mantle as it cools. The oceanic plate is thought to slide down this slope at the base of lithosphere, which may have a relief of 80 to 1000 kilometres. Therefore, the boundary between them is a slope down which the lithosphere slides. The mantle thickens as cooling converts asthenospheric mantle to lithospheric mantle. An even more important slope form on the base of the lithosphere mantle. Cooling sea floor subsides as it moves, and this subsidence forms the broad side slopes of the mid-ocean ridge. When a plate moves away from a divergent boundary, it cools and thickens. Ridge push or sliding plate force is a proposed mechanism for plate motion in plate tectonics. Mid-Atlantic Ridge is one of the most famous examples of divergent, stretching from north to south along the Atlantic Ocean, restricting the Continent of Europe and Africa to the Americas. While on the continental shelf, this process causes the formation of rift valley due to the gap between the two plates which are away from each other. In the ocean plate, this process causes the seafloor spreading. When a broken plate tectonics, lithospheric thinning layer and split, forming divergent boundaries.

Moreover, that will also form various types of deposition of sedimentary basins such as trench, fore arc basin, back arc basin, and basin between the mountains.īased on the direction of its movement, the plate boundary between tectonic plates with the other plate boundaries are divided into three types.ĭivergent plate boundaries occurs on two tectonic plates are break apart. The movement of the earth's crustal plates that collide with each other will form the subduction zone and cause the forces acting both horizontally and vertically, which will form the folds of the mountains, volcanoes track or magmatic, fracturing the rock, and the lines of tectonic earthquakes and the formation of a particular region. The tectonic plates of the earth is not stationary, but moves relative with the speed of 1 to 10 cm per year. Minor Plates (≥ 1 million km 2, ≤ 10 million km 2) These ten plates comprise the bulk of the continents and the Pacific Ocean. The lithosphere is divided into several tectonic plates intersect with each other.

3.3.2 Lithospheric Compression or Shortening and Flexure.

2.3.2 The discovery of fossils from animals and plants are widespread and separated on several continents.

1.2 Minor Plates (≥ 1 million km 2, ≤ 10 million km 2).

Plate boundary