Section 10.2 Types of Plate Boundaries Plate boundaries can be located anywhere such as in the ocean, along the edge of a continent or in a continent. Three Types of Plate Boundaries Divergent Convergent Transform

Divergent Boundary Divergent boundary two plates move away from each other. As the ocean moves apart, magma comes up and forms new ocean mountains called mid-ocean ridges

Convergent Boundaries These are plate boundaries that form when 2 plates collide (3 different types) When an ocean plate collides with a land plate it sinks under the land Subduction zone – when one plate moves under another. This causes deep ocean trenches. Land-land plate collision – mountains are formed. Example – Himalaya mountains Ocean-ocean plates collide – form an island arc which is a chain of volcanic islands. Ex. Japan

Transform Boundaries Two plates slide past each other horizontally and they cause earthquakes.

Causes of Plate Motion Convection – is the movement of heated material due to differences in density which are caused by differences in temperature.

Mantle Convection Energy is generated by the Earth’s core and radioactivity within the mantle heat the material. The heated material rises and the cooler material sinks This causes the plates to move.

Ridge Push Newly formed rocks at a mid-ocean ridge is warmer and less dense than older rocks nearby. As the less dense rock is elevated, the older rock is pushed down. The warmer rock cools down, becomes more dense and pushes against the old rock in a process called ridge push.

Slab Pull As plates pull away from each other at mid-ocean ridges, magma from the athenosphere rises and forms a new lithosphere. The new lithosphere will become dense and pull the rest of the plate behind it in a process called slab pull