Chapter 9 Section 3

Shaeed MarshallPer. 1

Key Concept 1.What Is Seafloor Spreading?

-Seafloor Spreading is the process by which plate tectonics produces new oceanic lithosphere.

Key Concept 2.What Is A Subduction Zone?-A Subduction Zone occurs when one oceanic plate is forced down into the mantle beneath a second plate.

Oceanic RidgeA continuous elevated zone on the floor of all major oceans basins and varying at the crests of ridges represent divergent plate boundaries

Rift ValleyA Rift Valley is a deep faulted structure found along the axes of divergent plate boundaries; Rift valleys can develop on the seafloor or on land.

TrenchA Trench is a surface feature in the seafloor produced by the descending plate during subduction.

Continental Volcanic ArcContinental Volcanic Arcs are mountains formed in part by volcanic activity caused by the subduction of oceanic lithosphere beneath a continent.

Volcanic Island ArcA Volcanic Island Arc is a chain of volcanic islands generally located a few hundred kilometers from a trench where subduction of one oceanic slab beneath another is occurring.

The End.

The End