Chapter 8 Flashcards
Is oceanic crust or continental crust denser?
Oceanic crust (basalt)
Why is density important for subduction process?
Because plates collide and crust is dragged into the mantle, melts and enters convection currents.
Subduction zones
where one plate slides beneath another
Which process destroy oceanic and continental crusts?
subduction zones-convergent
What process happens at divergent boundaries?
constructional process, sea floor spreading, continents pull apart
What process happens at convergent boundaries?
characteristics of collision zones, where areas of continental and oceanic crust collide and crust is lost—destructional process
What process happens at transform boundaries?
plates slide laterally past one another at right angles to a sea-floor spreading center—frictional transformation
How are hotspots formed?
fixed point where magma rises to surface
Do hotspots move?
yes over the years they do move
sea floor spreading
upwelling flows of magma along the world wide system of ocean ridges
what volcanoes are formed convergent boundaries?
Explosive
What type of boundaries form new crust?
divergent—through seafloor spreading
What boundary is the San Andreas Fault? What event often happens here?
Transform boundary, earthquakes
What feature gave rise to the Hawaiian islands?
hotspots
What continent collision formed Appalachian mountains?
continent-continent collision
