Subduction Plate Boundaries

When one plate-either an oceanic plate or a continental plate slides over another oceanic plate they form a SUBDUCTION ZONE and a deep trench forms.

What happens at these SUBDUCTION ZONES?

Volcanoes form as the molten rock breaks through the surface of the earth.
Example: Mt. Saint Helens

Mountain Ranges form over time when the layers of molten rock at the surface harden and then encloses the chambers beneath.
Example: Sierra Nevada Mountains

Volcanic Mountain Chain Island Arcs form where oceanic convergent plates at the subduction zone meet and a curved volcanic mountain chain forms above the subducting plate.
Example: Aleutian Peninsula of Alaska.

Aleutian Peninsula of Alaska

1. Why do volcanoes form at convergent boundaries with subduction zones? As one plate slides over another plate a deep trench forms and when the molten rock breaks through a volcano is formed The plates join together and form a volcano. 2. Which is an example of a volcanic mountain chain island arc? Aleutian Peninsula of Alaska Mt. Saint Helens 3. What causes the subduction zone? The two plates moving away from each other One plate sliding over another plate 4. How are mountain ranges formed? Over time the lava that comes to the surface cools and solidifies forming mountains Over time the lava gets hot and soft forming mountains