flash cards
plate tectonics
the theory that pieces of earths lithosphere are in constant motion, driven by convection in the mantle.
plate
a section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental oceanic crust.
lithosphere
the solid layer of earths crust and upper mantle
volcano
a weak spot in the crust where magma has come to the surface
ring of fire
a major belt of volcanoes that rims the pacific ocean
where do volcano belts form?
along the boundaries of earths plates
convergent plate boundary
a plate boundary where two plates moved towards each other
subduction
the process by which oceanic crust sinks beneath the deep ocean trench and back into the mantle at a convergent boundary
deep ocean trench
a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle
transform boundary
a plate boundary where two plates move past each other in opposite directions
what occurs at transform boundary?
earthquakes
crust is neither created or destroyed
divergent plate boundary
a plate boundary where two plates move away from each other
mid ocean ridge
an under sea mountain chain where new ocean floor is produced; a divergent plate boundary
rift valley
a deep valley that forms where two plates move apart
sea floor spreading
the seafloor spreads along both sides of a mid ocean ridge as new crust is added. as a result, the ocean floors move like conveyor belts, carrying the continents along with them.
