PLATE BOUNDARIES
Instructional Goals
Explain how each of the three plate boundaries are formed
Predict the resulting landforms from each boundary
Identify examples of plate boundaries
What do you know?
What do you know about earthquakes, mountains, etc?
Plate Boundaries
The place where two plates meet is called a plate boundary
Types of Plate Boundaries
Divergent Convergent Transform
Divergent Boundaries
Plates moving away from each other When do divergent boundaries occur?
Examples of Divergent Boundaries Mid-Atlantic Ridges Iceland (rift area) Red Sea Lake Baikal East African Rift
Convergent Boundaries
Plates are moving towards one another (colliding)
Destroys crust What happens at a convergent boundary
depends on the plates
Oceanic-Continental
- oceanic plate subducts because it is more dense
- examples: Andes Mountains Mount St. Helens (Juan de Fuca subducts
beneath the North American plate)
Oceanic-Oceanic
- oldest crust subducts - volcanic island chains - examples: Philippines Japan Aleutian Islands
Continental-Continental
- neither plate subducts - forms mountains - Examples Himalayas Appalachians Rockies Alps
Transform Boundary
- forms everywhere ridge is not a straight line
- two plates slide past each other - crust is conserved
Examples
San Andreas Fault Pacific Plate is moving faster than
North American plate at a rate of about 2 cm per year
http://www.learner.org/interactives/dynamicearth/plate.html
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0804/es0804page01.cfm?chapter_no=visualization
How does it all connect?
Earth layers Moving Plates
Continental Drift Plate Boundaries
Divergent, convergent, transform fault Earthquakes, volcanoes and mountains
and things
Journal
“Tectonic” comes from the Greek word tektonikos, which means “of a builder”. Why is this word appropriate for tectonic plates? In what ways are tectonic plates responsible for building/destroying features of the Earth’s surface?