plate tectonics
The theory that explains why and how continents move is called ?
Continental drift
A narrow valley that forms where the plates separate at a divergent boundary is called a ?
Mid-ocean ridge
When is a volcano formed on the edge of a continent?
when oceanic and continental plates converge
What are 3 types of volcanoes ?
shield volcanoes, cinder cone, strato/composite volcanoes
what does geologic features at continental convergent boundaries?
mountains
What is "plastic' rock, and how does it move ?
Asthenosphere it flows very slowly
What are most divergent boundaries located ?
Ocean floor
What is a shield volcano ?
broad, gently sloping volcano built from basaltic lava
what are 2 categories of eruptions ?
explosive & quiet eruptions
why are mountains formed along a contineal convergent boundary ?
the continental plates are not dense enough to subduct
A sudden movement along the boundary of a tectonic plate is a ?
Earthquakes
Describe an example of a rift valley ?
The Red sea
what are 3 places volcanoes form ?
mid-ocean ridges, tectonic plate boundaries and subduction zones.
What is transform fault ?
a boundary where 2 plates slide past each other
What causes convection currents in the mantle ?
uneven heating in the mantle
A zone of active volcanoes that encircles the Pacific Ocean is known as the ?
Pacific Ring of Fire
What deep-ocean feature forms at subduction zones ?
Deep-ocean trenches
What is sea floor spreading evidence ?
studying earthquakes at and around deep ocean trenches
why do trenches form at convergent boundaries ?
subduction of the denser lithospheric plate creates a depression
Where are the edges of most plates ?
beneath the oceans
What happens to magma at divergent boundaries ?
It rises to the surface and cools to form new ocean lithosphere
An example of a feature tat formed when two plates made of oceanic lithosphere collided is ?
Volcanic mountains
What is magma ?
rock temperature rises above its melting point
why are mi-ocean ridges formed along oceanic divergent boundaries ?
as the plates pull apart, magma rises up through the crack creating new crust
what determine the type of plate boundary?
whether the plates are moving toward each other, moving away from each other or sliding past each other