When one plate slides beneath another it carries volatiles such as water with it. These substances get into the mantle rock and lower the temperature needed for it to melt. This molten material then rises as it is less dense and forms volcanoes as it reaches the surface.
Subduction processes often causes the melting of the mantle that produces a volcanic arc
Water and other volatiles carried into the mantle by the subducting plate cause mantle rock to melt. The molten rock then rises through the crust to form volcanoes.
Subduction creates immense pressure and heat, melting the rock just below the surface of a fault line. The building pressure often gives way and causes volcanic events.
Volcanoes tend to form at convergent subduction boundaries and divergent plate boundaries. One good example would be the broad ring of volcanoes that have formed around the boundary of the Pacific plate. This is why this region is known as the ring of fire. There is also a very long chain of undersea volcanoes that occur at the mid ocean ridges. In some places these have formed islands such as Iceland. Where subduction occurs (along the west coast of South America, and the west coast of the USA for example) volcanoes form, e.g. Subduction zones also form volcanic island arcs such as the Aleutian island chain in Alaska.
Mountains, volcanoes, earthquake zones
You could find mountains, valleys, faults, subduction zones, trenches, or experience volcanism or earthquakes.
Scientists usually find the age of volcanoes through radiometric dating of their rocks.
Near subduction zones.
Subduction creates immense pressure and heat, melting the rock just below the surface of a fault line. The building pressure often gives way and causes volcanic events.
usually you find most of the zones of earthquakes and volcanoes at a plate boundary.
Volcanoes tend to form at convergent subduction boundaries and divergent plate boundaries. One good example would be the broad ring of volcanoes that have formed around the boundary of the Pacific plate. This is why this region is known as the ring of fire. There is also a very long chain of undersea volcanoes that occur at the mid ocean ridges. In some places these have formed islands such as Iceland. Where subduction occurs (along the west coast of South America, and the west coast of the USA for example) volcanoes form, e.g. Subduction zones also form volcanic island arcs such as the Aleutian island chain in Alaska.
There are no active volcanoes in Montana. You have to go further west to the Cascade Range to find volcanoes. The volcanoes in the Cascades are caused by the subduction of the oceanic crust under the continental crust.
at the very bottom of the ocean, usally
Mountains, volcanoes, earthquake zones
At Fault lines, or places of crustal activity :) Volcanoes usually form near plate boundaries where subduction is occurring. This causes magma from the mantle to rise up onto Earth's surface and form volcanoes. Most volcanoes are formed in this way. Volcanoes can also be formed by hotspots. Magma from the mantle rises through these hotspots and find their way to Earth's surface, forming volcanoes in a chain like Hawaii. Well, volcanoes are usually the land that creates islands like Hawaii. I'm doing homework right now and i'd say an island? If not that, i'd go with the first two answers. :)
You could find mountains, valleys, faults, subduction zones, trenches, or experience volcanism or earthquakes.
They usually show up in desert zones.
Scientists usually find the age of volcanoes through radiometric dating of their rocks.
There are many explanation to your question. The most abundant type of rocks in collision zones are metamorphic rocks. But if there is a igneous it can as a result of convergence boundaries. In subduction zones where rising magma are penetrate through weaker rocks to form form lava and when solidified forms igneous rocks. You can also find them in accretion zones. Where 2 continental plates are accreted due to plate movement. They are not newly formed igneous. they have been there for years before accretion.