Answer
A continental volcanic arc and a volcanic island arc are both types of volcanic arcs that form in subduction zones. However, they differ in their location and composition.
A continental volcanic arc is formed when an oceanic tectonic plate subducts beneath a continental plate. As the oceanic plate sinks into the mantle, it undergoes partial melting due to the increase in temperature and pressure. The molten rock, or magma, rises to the surface and forms a volcanic arc on the continental crust. This volcanic arc is characterized by a chain of volcanoes that are located on the continental landmass. Examples of continental volcanic arcs include the Andes in South America and the Cascade Range in North America.
On the other hand, a volcanic island arc is formed when two oceanic tectonic plates converge and one plate subducts beneath the other. As the subducting plate sinks into the mantle, it undergoes melting, leading to the formation of magma. The magma rises to the surface and forms a chain of volcanic islands that are located in the ocean. These volcanic islands are often curved in shape and parallel to the subduction zone. The Aleutian Islands in Alaska and the Japanese archipelago are examples of volcanic island arcs.
In summary, the main distinction between a continental volcanic arc and a volcanic island arc lies in their location. Continental volcanic arcs are formed on a continental landmass above a subducting oceanic plate, while volcanic island arcs are formed in the ocean where two subducting oceanic plates converge.
Work Step by Step
A continental volcanic arc and a volcanic island arc are both types of volcanic arcs that form in subduction zones. However, they differ in their location and composition.
A continental volcanic arc is formed when an oceanic tectonic plate subducts beneath a continental plate. As the oceanic plate sinks into the mantle, it undergoes partial melting due to the increase in temperature and pressure. The molten rock, or magma, rises to the surface and forms a volcanic arc on the continental crust. This volcanic arc is characterized by a chain of volcanoes that are located on the continental landmass. Examples of continental volcanic arcs include the Andes in South America and the Cascade Range in North America.
On the other hand, a volcanic island arc is formed when two oceanic tectonic plates converge and one plate subducts beneath the other. As the subducting plate sinks into the mantle, it undergoes melting, leading to the formation of magma. The magma rises to the surface and forms a chain of volcanic islands that are located in the ocean. These volcanic islands are often curved in shape and parallel to the subduction zone. The Aleutian Islands in Alaska and the Japanese archipelago are examples of volcanic island arcs.
In summary, the main distinction between a continental volcanic arc and a volcanic island arc lies in their location. Continental volcanic arcs are formed on a continental landmass above a subducting oceanic plate, while volcanic island arcs are formed in the ocean where two subducting oceanic plates converge.
