Plate Tectonics

Inner core: Super-hot but solid Outer core: Melted iron and nickel (liquid) Mantle: Silicon, aluminum, iron, magnesium, oxygen, and other elements (liquid) Crust: Rocky shell (from between 2-75 miles thick)

Continental Drift Theory The theory that the continents were once joined as a supercontinent (Pangea) and have drifted apart over millions of years. What is the evidence? *The plates only move about 1 inch per year.

Help For Gondwanaland assignment Prince Harald Wilhelm II Oates

Types of colliding & spreading 1. The Himalayas are forming from two continental plates colliding and pushing up.

Types of colliding & spreading 1. The Himalayas are forming from two continental plates colliding and pushing up. 2. The Andes are being formed by subduction where an oceanic plate slides under a continental plate causing volcanoes that create mountains.

Types of colliding & spreading 1. The Himalayas are forming from two continental plates colliding and pushing up. 2. The Andes are being formed by subduction where an oceanic plate slides under a continental plate causing volcanoes that create mountains. 3. Accretion is where an oceanic plate comes together with a continental plate and levels off seamounts (underwater mountains) piling up debris in the trench. This causes a slow expansion of a continent outward – U.S. west of the Rockies.

Tsunamis (massive waves triggered by earthquakes) can be caused by subduction. Banda Ache, Indonesia- around 250,000 killed from waves 100 feet tall.

Divergent Plate Boundaries Spreading (divergent plate boundaries) is where two plates pull apart resulting in a “rift.” This allows magma to rise creating new land. Ex: Mid-Atlantic Ridge (longest mountain range)

Faults Where two plates slide past each other, often getting stuck and then slipping causing an earthquake.