![]() ![]() ![]() Seismic tomography reveals pieces of lithosphere that have broken off during convergence. It is likely that the plate may break along the boundary of continental and oceanic crust. In some instances, initial convergence with another plate will destroy oceanic lithosphere, leading to convergence of two continental plates. Some lithospheric plates consist of both continental and oceanic lithosphere. It was formed subduction because of the Philippine Plate over the Pacific plate. Both dehydration and partial melting occurs along the 1,000 ☌ (1,830 ☏) isotherm, generally at depths of 65 to 130 km (40 to 81 mi). Marianas Trench is the example of the oceanic-oceanic convergent plate boundary. This releases water into the hotter asthenosphere, which leads to partial melting of asthenosphere and volcanism. As the relatively cool subducting slab sinks deeper into the mantle, it is heated, causing hydrous minerals to break down. The force of gravity helps drive the subducting slab into the mantle. Subduction begins when this dense crust converges with less dense crust. As this new crust is pushed away from the spreading center by the formation of newer crust, it cools, thins, and becomes denser. These convection cells bring hot mantle material to the surface along spreading centers creating new crust. Convection cells are the result of heat generated by the radioactive decay of elements in the mantle escaping to the surface and the return of cool materials from the surface to the mantle. Plate tectonics is driven by convection cells in the mantle. Large earthquakes occur along these boundaries as the plates grind by each other.Region of active deformation between colliding tectonic plates Simplified diagram of a convergent boundary Many transform boundaries are found on the ocean floors, the San Andreas Fault in California is the most recognized transform boundary located on land. These boundaries are usually faults that offset and connect spreading centers. Transform boundaries occur where two plates slide past each other horizontally. The Himalayan mountain range is the most recognized continent-continent collision. Large-scale mountain building results from the intense collision. The continent buckles, squeezes, folds, thrusts, and deforms. When two continental plates converge, collision occurs. A well-noted example of an island arc is the Alleutian Islands.Ĭontinental-continental convergence produces different results. Magma created by the melting crust rises to the surface creating chains of volcanoes, known as island arcs. With the collision of two oceanic plates, subduction still occurs. Oceanic-oceanic convergence involves similar processes. Great amounts of stress are produced along these boundaries and build up over time, producing some of the world's most intense earthquakes. ![]() This process is known as subduction and deep trenches are created by this process. At an estimated depth of 100 km the crust melts and rises as magma, forming strata volcanoes on the surface directly above. Oceanic-continent convergent boundaries occur when the dense oceanic crust approaches the buoyant continent and the ocean crust sinks below the continent. For example, the Mid-Atlantic Ridge is the focus of rifting that seperated North and South America from Europe and Africa and formed the Atlantic ocean. Spreading centers also rift apart continents, allowing oceans to form between them. Which plate undergoes subduction at oceanic - continental convergent plate boundaries Why answer choices. Divergent boundaries are also known as spreading centers and generate an underwater mountain chain which encircles the earth much like the seams of a baseball. Younger rocks are located at the boundary whereas the older rocks move farther and farther away. Examples of continental-continental convergent boundaries include the Himalayas and the Appalachian Mountains. Instead, they crumple and fold, creating large mountain ranges. Divergent and transform plate boundaries are located within the archipelago, while a convergent boundary exists directly off the coast of Ecuador.ĭivergent Boundaries occur where two plates move apart and new crust is formed from magma generated in the mantle below. There are three types of convergent boundaries: where two conti- nental plates meet, where two oceanic plates meet, or where an oceanic plate and a continental. At a continental-continental convergent boundary, neither plate subducts because they are too buoyant. The Galapagos contains three types of plate boundaries. There are three types of motions between the tectonic plates: divergence, convergence, and lateral. Also, the figure annotates Earth's three different tectonic plate boundaries: convergent, divergent and transform. Cross-sectional view of the Earth's lithosphere and lower mantle. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |