Plate Tectonics

Theory of Plate Tectonics Earth’s top layers (Lithosphere) is broken into 7 plates, which move around

The Lithosphere Crust and Upper part of the Mantle

What Causes the Plates to Move? Convection- hot magma rises, cool magma sinks (like a lava lamp)

Two Types of crust Continental Crust- made of granite (light) Oceanic Crust- made of basalt (heavy)

Plate Boundaries Cracks in the plates are called faults

Types of Boundaries (Faults) Convergent Boundary Divergent Boundary Transform Boundary

Divergent Fault Plates move away from each other Forms volcanoes and new crust Ex) Iceland, mid-Atlantic ridge

Transform Fault Plates slide past each other Creates earthquakes Ex) San Andreas Fault in California

Convergent Fault Plates move toward each other Earthquakes, forms mountain ranges Ex) Himalayan Mountains

Continental-Continental Boundary Plates fold, create mountains

Oceanic-Oceanic Boundary Creates trenches (deep valleys) Forms volcanoes Ex) Aleutian Islands (Alaska)

Oceanic-Continental Boundary Oceanic plate pushes down because it is more dense Creates mountain ranges Ex) Andes mountains