PlatePlateTectonicsTectonics

• Wilson- combined Continental Drift, Sea-Floor Spreading.

• A geologic theory that states that pieces of Earth’s lithosphere are in constant, slow motion driven by convection currents in the mantle.

Plate Tectonics

CD RiftEvidence

Earth’s Plates

CD RiftEvidence

ClimateConvergent Boundaries

• Definition: Two plates move towards each other. (Collision Boundary)

• Other Info: – Density plays a role.– Effect on Crust:

• Cont/Cont Collision creates mountains• Subduction- destroys ocean crust.

• Geologic Features:– Cont/Cont- Forms Mountains- • Himalayas

Convergent Boundaries

• Geologic Features:– Ocean/Ocean (Subduction boundary)• Denser Ocean plate subducts.

– Deep sea-trenches, Volcanic Island Arc

– Cont/Ocean (Subduction boundary)• Denser Ocean plate subducts.

– Deep sea-trenches, Volcanoes (Mt. St. Helens)

Convergent Boundaries

• Definition- Two plates pull apart.• Motion:

• Geologic Features- Forms a rift valley.• Other Info- – Great Rift Valley– Mid-Ocean Ridge

ClimateDivergent Boundaries

• Geologic Features- – Forms a rift valley.• Chain of volcanoes

– Creates new ocean floor.

• Other Info- – Great Rift Valley– Mid-Ocean Ridge

Divergent Boundaries

• Two plates slide past each other in opposite directions.

• Motion of Plates:

• Geologic Features: – Faults- break in crust

• Other Info: – San Andreas Fault– Causes Earthquakes

ClimateTransform Boundaries

Pacific Plate

North American

Plate

ClimateBoundary Diagrams

• Boundary: – Transform

• Examples: – San Andres Fault

• Motion: – slide past each other.

• Features formed: – Fault

• Boundary: – Divergent

• Example: – Mid-Atlantic Ridge

• Motion: – Pull apart, move away

• Features formed: – Mid-Ocean Ridge

• Underwater Volcanoes

Boundary DiagramsBoundary Diagrams

ClimateBoundary Diagrams

• Boundary: Divergent

• Example: Great Rift Valley

• Motion: Pull apart, move away

• Features formed: Rift Valley

Divergent Boundary

ClimateBoundary Diagrams

• Boundary: Convergent

• Examples: Himalaya, Mts.

• Motion: Towards each other

• Features formed: Mt. Ranges

ClimateBoundary Diagrams

• Boundary: Convergent

• Examples: – Japan.– Aleutian Islands

• Motion: – Towards each other

• Features formed: – Subduction, Trench, Volcanic island arc

ClimateBoundary Diagrams

• Boundary: Convergent

• Examples: – Mt. St. Helens

• Motion: – Towards each other

• Features formed: – Subduction, Trench, Volcanoes