17.3 - Plate Boundaries
Divergent Boundaries
Regions where two tectonic plates are moving apart
What is a famous Oceanic-Oceanic Convergent Boundary?
The Marianas Trench
Where are most divergent boundaries found?
Along the seafloor in rift valleys
Divergent boundaries ... crust
Create
What are transform boundaries responsible for?
Earthquakes
What are divergent boundaries associated with?
High heat flow, volcanism, and earthquakes
Tectonic Plates
Huge pieces of crust and the rigid upper mantle that fit together at their edges to cover Earth's surface
What does the magma that rises from an Oceanic-Continental Convergent Boundary form?
It also produces a trench and volcanic arc but instead of islands, a chain of volcanoes form on the edge of the continental plate >>*Results in a mountain range with many volcanoes*
What does the magma that rises from an Oceanic-Oceanic Convergent Boundary form?
It forms an arc of volcanic islands parallel to the trench
Oceanic-Oceanic Convergent Boundaries creates ... ?
Ocean trenches, the crust is then melted and recycled
... crust is denser than ... crust
Oceanic, continental
What is a famous Oceanic-Continental Convergent Boundary?
The Andes Mountain Ranges
What is a famous Continental-Continental Convergent Boundary?
The Himalayas
What is a famous Transform Boundary?
The San Andreas Fault
What happens to the crust when a transform boundary occurs?
The crust is only deformed or fractured
What happens after a Continental-Continental Convergent Boundary occurs?
The edges of both plates become crumpled, folded, and uplifted
Explain how Continental-Continental Convergent Boundaries occur
The oceanic crust, already below (but towing the continental) the plate descends beneath the continental crust at the subduction zone -The continental plate being towed behind will not sink and will collide with the other contninental plate
What does water do for the subducting plate (in Oceanic-Oceanic Convergent Boundaries)?
Water carried in by the subducting plate lowers the melting temperature of the plate which makes it melt at shallower depths
Rift Valley
When continental crust begins to separate and a long, narrow depression occurs (might lead to a new ocean basin)
Mid-Ocean Ridge
When magma rising through a rift form a continuous mountain chain on the ocean floor
Convergent Boundaries
When two plates move toward each other
Oceanic-Oceanic Convergent Boundaries
Where subduction occurs when a denser oceanic plate descends under another oceanic plate
Oceanic-Continental Convergent Boundaries
Where the denser oceanic plate subducts under the continental plate
Subduction
Where the denser plate descends below the other, less-dense plate
Continental-Continental Convergent Boundaries
Where two continental plates collide
Transform Boundaries
Where two plates slide horizontally past each other
