Plate Tectonics Flashcards
What is divergent plate boundary?
Plates move apart as magma pushes upward from the mantle.
It cools and crystallizes to form a new crust.
What are divergent plates called?
Spreading centres
Rifts
Ridges
What are examples of divergent plate boundaries?
Mid-Atlantic Ridge
East African rift
What are divergent plates known as? And why?
Constructive because new crusts are formed
What is convergent plate boundary?
Plates move toward each other
(Associate with collision)
What are convergent boundaries called? And why?
Destructive margins because plates are destroyed.
What are the three classes of collisions for convergent plate boundaries?
- Oceanic plate- Continent plate
- Oceanic plate- Oceanic plate
- Continent plate- Continent plate (collision zones)
What is orogenesis? Where does it occur?
Processes of mountain building - occurs at
convergent boundaries.
What does ocean - continent plates mean?
Oceanic and continental plates move toward each other.
Oceanic plate is dense so it sinks under the continental plate (subduction)
What is an example of ocean - continent plates?
The Andes Mountains in Peru
What does oceanic- oceanic convergence mean?
The older oceanic plate subducts (sinks) leading to the formation of a deep offshore trench and seafloor volcanoes that can eventually form an island arc
What are examples of oceanic- oceanic convergence?
Marianas Trench
Aleutian Islands
Japanese Island Arc
What is continent-continent convergence mean?
- When two continents meet neither subducts because of the continental crust’s low density (neither is more dense)
(leads to thickening of the crust) - Crust buckles/crumbles and gets pushed up to form mountain ranges
What are examples of continent-continent convergence?
Himalayas Mountain
Tibetan Plateau
How are mountain belts formed?
What is the architecture of continent? Explain.
- Craton: oldest part of continent.
- (formed, evolved, and altered over years) - Orogens: bands of mountains.
- Continental Shield: assemblage of ancient cratons and orogens.
What is transform plate boundary?
Plates slide laterally past one another.
Effect is conservative as the lithosphere is neither created or destroyed.
What are examples of transform plate boundaries?
San Andreas Fault
- Pacific Plate slides past the North American Plate.
What is a hotspot?
