Transcript aka Subduction

Plate Tectonics
- theory stating that the Earth’s crust is made up of large, moving plates
- the major force in geomorphology.
Continental Drift
- Idea developed by Alfred Wegener in 1915.
- Proposed that the light continental crust “floated” on the dense oceanic crust.
- Proposed the idea of “Pangea”
- His theories were altered to create the modern view of plate tectonics.
Boundaries
-Three types of boundaries:
- Convergent
- Divergent
- Transform
Convergent Boundaries
-Boundary where plates push together.
- Three types:
- Continent/Continent - creates non-volcanic mountains (Himalayas)
Convergent Boundaries
Convergent Boundaries
-Boundary where plates push together.
- Three types:
- Continent/Continent - creates non-volcanic mountains (Himalayas)
- Ocean/Continent - aka Subduction - creates volcanic mountains
(Andes, Cascades)
- Ocean/Ocean - creates volcanic islands (Indonesia)
Divergent Boundaries
-Boundary where plates pull away from each other.
- Examples:
- Mid-Atlantic Ridge (Iceland)
- Great Rift Valley in Africa
Divergent Boundaries
Transform Boundaries
-Boundary where plates slide parallel to each other.
- Example: San Andreas Fault - major earthquakes
Plate Tectonics
Ring of Fire
- Area of subduction around the Pacific Ocean known for volcanoes.