Types of Convergent Plate Boundaries Essay Example | Topics and Well Written Essays - 750 words

Types of Convergent Plate Boundaries - Essay Example In a continental collision, the subducting plate is usually a plate with the oceanic crust that moves beneath the other plate with oceanic crust, therefore, moving beneath the other plate which can be made of either oceanic or continental crust. It is evident that during collisions between two continental plates large mountains ranges such as the Himalayas Mountains are made in the process. There are three types of convergent boundaries that can be subdivided into subduction and non-subduction. During the subduction types, there are two plates that the meet, the denser, cooler and heavier plate will dive below the lighter. The most floating plate one as it gets deeper into the mantle it then melts and creates a new magma (Ernst, 325-330). In this convergent boundary, two plates meet with the oceanic crust colliding, the one plate will be denser and heavier than the other, therefore, making it subduct. After the creation of the new magma, it then rises to the surface and pokes through the ocean surface as a submarine volcano. Connectively continuing eruptions will form a larger seamount where more and more eruptions will then eventually create a dry volcanic island in the ocean floor that will continue to erupt and build as long as it has a continued magma source. There is the presence of water in the rocks of the oceanic plate since they are made under the water in the oceanic floor. As the plate moves further down into the subduction zone more water contained in the plate is then squeezed out from the rocks when the plate begins to subduct. Nevertheless, the recrystallization of ocean floor rocks such as the serpentine that is unstable in the upper mantle recrystallizes forming olivine, causing dehydration through a loss of hydroxyl groups. In this case of oceanic-oceanic collision, the made magma will be mafic in nature with high iron and magnesium low silica making it very viscous. This result to shield volcanoes, due to this activity along an entire plane many volcanoes are made hence having a volcanic island and an arc of the chain of volcanoes.