Plate Tectonics
Introduction
Plate tectonics is the theory that the lithosphere is divided into separate oceanic and continental plates that are constantly moving, powered by convection currents in the mantle. Volcanic belts are created at plate boundaries because of the rising magma. The Ring of Fire is a major belt of volcanic activity surrounding the Pacific Ocean that includes many of the 600 volcanoes on land.
Divergent Boundaries
A divergent plate boundary is where two edges of an oceanic and oceanic, continental and continental, or oceanic and continental plate pull away from each other. It is here that new land is created and is one of the places where most volcanoes are located. The magma from the mantle flows up through this weak crack and creates new rock on the ocean floor or land. The mid-ocean ridge is a divergent boundary that is mostly underwater except for a few small areas.
Volcanoes develop along divergent boundaries, especially along the mid-ocean ridge, a large rift valley that runs through all Earth's oceans. They are constructed as the lava that gushes from cracks in the ocean floor along divergent boundaries turn to rock, build up, and vent more lava.
Convergent Boundaries
Some examples of convergent boundaries are deep-ocean trenches and subduction zones. A convergent boundary is where two plates, whether they be oceanic and oceanic, continental and continental, or oceanic and continental, come together and create a collision. It is here that land is destroyed and returned to the mantle or mountains are built. When plates converge, the denser of the two (usually the oceanic plate) dives down and into the mantle. If two continental plates collide, neither plate sinks below due to their lightness. Instead, mountain ranges are formed as the two pieces push against each other and build up mountains.
Convergent boundaries assist the forging of volcanoes. After completing the process of subduction, the now melted plate creates new magma that goes into the mantle and rises to the surface again, ready to erupt out of volcanoes. Convergent boundaries are also able create new volcanoes. The magma seeps up through cracks in the crust and erupts. This magma, now lava, hardens into rock and after numerous eruptions, a new volcano is established.
Since countless volcanoes are located on islands, island arcs are created by convergent boundaries. They are strings of islands that mimic the deep-ocean trench it was formed from.
Hot Spots
While most volcanic activity occurs along the Ring of Fire and plate boundaries, it is also able to build up in the middle of an oceanic or continental plate. Hot spots are created when magma from the mantle melts the crust above it and pushes itself up and through to the plate.
Volcanoes and continuous strings of volcanic mountains are created by hot spots when continental plates drift over the hot spots under oceanic plates. They may also form on dry land when hot spots are under continental plates.
Plate tectonics is the theory that the lithosphere is divided into separate oceanic and continental plates that are constantly moving, powered by convection currents in the mantle. Volcanic belts are created at plate boundaries because of the rising magma. The Ring of Fire is a major belt of volcanic activity surrounding the Pacific Ocean that includes many of the 600 volcanoes on land.
Divergent Boundaries
A divergent plate boundary is where two edges of an oceanic and oceanic, continental and continental, or oceanic and continental plate pull away from each other. It is here that new land is created and is one of the places where most volcanoes are located. The magma from the mantle flows up through this weak crack and creates new rock on the ocean floor or land. The mid-ocean ridge is a divergent boundary that is mostly underwater except for a few small areas.
Volcanoes develop along divergent boundaries, especially along the mid-ocean ridge, a large rift valley that runs through all Earth's oceans. They are constructed as the lava that gushes from cracks in the ocean floor along divergent boundaries turn to rock, build up, and vent more lava.
Convergent Boundaries
Some examples of convergent boundaries are deep-ocean trenches and subduction zones. A convergent boundary is where two plates, whether they be oceanic and oceanic, continental and continental, or oceanic and continental, come together and create a collision. It is here that land is destroyed and returned to the mantle or mountains are built. When plates converge, the denser of the two (usually the oceanic plate) dives down and into the mantle. If two continental plates collide, neither plate sinks below due to their lightness. Instead, mountain ranges are formed as the two pieces push against each other and build up mountains.
Convergent boundaries assist the forging of volcanoes. After completing the process of subduction, the now melted plate creates new magma that goes into the mantle and rises to the surface again, ready to erupt out of volcanoes. Convergent boundaries are also able create new volcanoes. The magma seeps up through cracks in the crust and erupts. This magma, now lava, hardens into rock and after numerous eruptions, a new volcano is established.
Since countless volcanoes are located on islands, island arcs are created by convergent boundaries. They are strings of islands that mimic the deep-ocean trench it was formed from.
Hot Spots
While most volcanic activity occurs along the Ring of Fire and plate boundaries, it is also able to build up in the middle of an oceanic or continental plate. Hot spots are created when magma from the mantle melts the crust above it and pushes itself up and through to the plate.
Volcanoes and continuous strings of volcanic mountains are created by hot spots when continental plates drift over the hot spots under oceanic plates. They may also form on dry land when hot spots are under continental plates.