Assignment task:
1. Along the Peru-Chile trench, oceanic crust and continent-derived sediments are subducted under South America and melted to magma, which rises to the surface from volcanic deposits. What is the average type of volcanic type of deposits? What kind of volcano?
2. Iceland is an above-water portion of the Mid-Atlantic Ridge consisting of oceanic crust recently derived from the mantle. What is its specific rock type?
3. What plate boundary types are covered at Mendocino Triple Junction?
4. The Cascade Range is one segment of a larger volcanic chain called. It is also part of an active mountain-building segment of North America called?
5. Why do the Cascades terminate in Northern California?
6. Where on the Juan de Fuca plate would the oldest basalts be found?
7. What geographic portions of the Cascades have shown the most recent activity? Why are composite chains like the Cascades located landward of the boundary where the plates converge?
8. Explosive volcanic activity is associated with lava composition and quiet flows with what composition?
9. What two population centers are near enough to threaten Cascade volcanos to consider volcanic hazards in their overall civil defense plan?