Section 1 Definitions

• Continental drift is the theory that the continents are mobile and have moved across the Earth’s surface
• palaeomagnetism is the changes in the alignment of magnetic particles in rocks
• convection currents are movements of semi molten material in the asthenosphere which occur as this material rises and falls as it heat and cools, causing movements in tectonic plates
• subduction is the the process at convergent boundaries where an oceanic plate descends into the mantle and is destroyed
• the Benioff Zone is the boundary between a subduction oceanic plate and an overriding continental plate
• plutons are masses of igneous rock injected into overlying rock created by destroyed oceanic crust
• island arcs are chains of volcanic islands that are formed along a subduction zone