What causes volcanism at a subduction zone, and how does Bowen's reaction series explain the
composition of the magmas there? What will be an ideal response?
At subduction zones, the magmas are intermediate or felsic. The suducting plate reaches a depth where
the temperature is high enough to begin partial melting, and the oceanic crust on top of the plate loses
its water, which rises into the overlying mantle and enhances melting. The melting of the oceanic crust
yields more silica-rich magmas than at the spreading ridges, and subducted sediments also contribute
silica to the magma. Finally, as the magma rises through the continental crust (if it's an ocean,
continent subduction zone), the magma picks up silica-rich minerals.
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What transfers heat upward into the atmosphere?
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Which of the following are examples of fault-block mountains?
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