convergent Boundary
In Plate Tectonics, a Convergent Boundary, also known as a destructive plate boundary because of Subduction. A Convergent Boundary is an actively deforming region where two or more tectonic plates or fragments of the Lithosphere move toward one another and collide. As a result of pressure, friction, and plate material melting in the Mantle, earthquakes and volcanos are common near Convergent Boundaries. When two plates move towards one another, they form either a Subduction zone or a Continental collision, this depends on the nature of the plates involved. In a subduction zone, the subducting plate, which is normally a plate with oceanic crust, moves beneath the other plate, which can be made of either Oceanic or Continental Crust. During collisions between two Continental plates, large mountain ranges, such as the Himalayas are formed.
oceanic-continental convergence
When an Oceanic and a Continental Plate converge the Oceanic Plate sinks underneath the Continental Plate. The area were the plate sinks into the Mantle is called a Subduction zone. Subduction Zones along an Oceanic-Continental boundary create a deep-sea trench. A long, narrow, deep depression in the sea floor. Many trenches occur around the Margin of the Pacific Ocean because of Subduction. High temperatures cause rock to melt around the Oceanic Plate as it sinks underneath the Continental Plate. The newly formed magma is forced upward through the Upper Plate causing volcanoes.
The impact of the plates colliding also causes cracks to form in the crust. The heat and pressure from the mantle forces the acidic magma to rise up these cracks. As the magma continues to rise up the cracks, it escapes onto the surface and solidifies, building up a volcano. Magma on the surface is now known as lava. so, an acid lava volcano is formed. The converging of the oceanic and continental plate also cause deep oceanic trenches and fold mountains to form.
The impact of the plates colliding also causes cracks to form in the crust. The heat and pressure from the mantle forces the acidic magma to rise up these cracks. As the magma continues to rise up the cracks, it escapes onto the surface and solidifies, building up a volcano. Magma on the surface is now known as lava. so, an acid lava volcano is formed. The converging of the oceanic and continental plate also cause deep oceanic trenches and fold mountains to form.
continental-continental convergence
When two Oceanic Plates meet the older, colder, and denser plate bends and sinks into the Mantle. New Crust is then formed as the magma rises to create volcanoes. It also creates deep-sea trenches. Continent-continent convergent zones are tectonic sumo wrestling matches in which neither plate is subducted, because continental rock is too light to be carried very far into the dense mantle about 150 km down at most. Instead the continental crust crumples into thick knots—tectonic mountain ranges—exposing deep-seated granites and gneisses with relatively little volcanism. The continental crust may also be cracked in pieces and shoved aside. Both of these responses are seen to perfection in the great foldbelt that stretches from Turkey to China. There the African, Arabian and Indian plates are moving northward into the Eurasian plate, respectively raising the Anatolian, Irann and Himalayan/Tibetan highlands. A small example occurs in southeastern Alaska as well. These places, especially Tibet, are sites of extreme tectonics.
oceanic-oceanic convergence
When two continental plates collide and crumple up tall mountain ranges may form. Earthquakes are common at these Convergent Boundaries. Volcanoes do not form however because there is little or no subduction when two plates collide. Oceanic-oceanic convergent zones are mostly hidden under the sea. only arches of volcanic islands mark them, made of dark and heavy basaltic lavas. The western Pacific Ocean is full of these—from north to south they include the Aleutian, Kuril, Japanese, Ryukyu, Izu-Bonin, Philippine, Mariana, Solomon and Tonga-Kermadec island arcs. In the Atlantic are the Caribbean and South Sandwich island arcs. In the Indian Ocean is the tangle of arcs that makes up the Indonesian archipelago.