Plate Tectonics
seamount
a volcanic mountain rising from the ocean floor that doesn't reach the surface
Where do earthquakes occur?
along all types of plate boundaries
subduction
The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary.
Seafloor Spreading
The process that creates new seafloor as plates move away from each other at the mid-ocean ridges
Asthenosphere
The soft layer of the mantle on which the lithosphere floats.
Oceanic Lithosphere
made out of basalt; denser that's why it sits lower in the asthenosphere
Continental Lithosphere
made out of granite; not as dense as basalt that's why it sits higher up in the asthenosphere
What is created at an oceanic-oceanic divergent boundary?
mid-ocean ridges
What is created at a continental-continental convergent boundary?
mountains
lithosphere
the rigid outer part of the earth, consisting of the crust and upper mantle.
What is created at a transform boundary?
earthquakes
Divergent Boundary
A plate boundary where two plates move away from each other.
transform boundary
A plate boundary where two plates move past each other in opposite directions; earthquakes are common here
Convergent Boundary
A plate boundary where two plates move toward each other.
mid-ocean ridge
An undersea mountain chain where the new ocean floor is produced; a divergent plate boundary.
convection currents
Circular currents in the mantle caused by the magma being heated by the core of the Earth.
tectonic plates
a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle
volcanic island
an island formed when an underwater volcano builds up enough lava and ash to rise above sea level
Trench
extremely deep areas in the ocean that are created by a subducting plate
What is created at an continental-continental divergent boundary?
rift valley
What is created at an oceanic-continental convergent boundary?
trenches, coastal mountains, volcanoes
What is created at an oceanic-oceanic convergent boundary?
trenches, island arcs, volcanoes