plate tectonics - exam 1 Flashcards
the outermost layer of crust and uppermost mantle
lithosphere
the weak sphere
asthenosphere
base of asthenosphere to the core mantle boundary and more rigid than asthenosphere
mesophere
continental crust
comprises continents
oceanic crust
underlies most ocean basins
divergent plate boundaries
move apart
convergent plate boundaries
move together
transform plate boundaries
plates grind past each other without the production or destruction of lithosphere
new ocean floor is generated as two plates move apart
seafloor spreading
most divergent plate boundaries are located along the crests of
oceanic ridges
-young crust
-oceanic ridge
-ocean floor eruptions
-few volcanoes
-shallow earthquakes
divergent boundary characteristics
plates move toward one another and collide. lithosphere is often destroyed in the subduction zone
convergent plate boundaries
ocean - ocean
ocean - continent
continent - continent
types of convergent plate boundaries
-older ocean crust subducts
-volcanoes abundant above subducting plate
-volcanic island arcs
-mountains on overriding plate
convergent boundary characteristics
-continental and oceanic
-shallow earthquakes
-no volcanoes
-offsets similar aged rocks
transform boundary characteristics
a supercontinent consisting of all of earths landmasses once existed
referring to pangea
continental drift hypothesis
driving forces of plate tectonics and plate motion
slab pull
ridge push
mantle convection
subducting plates are pulled down into the mantle due to their higher density
slab pull
oceanic plates move from higher to lower elevation pulling plates apart
ridge push
mantle motion drags plates along
mantle convection
who outlined the continental drift hypothesis and supercontinent (pangea) theory?
alfred weggener
what does lithos mean in lithosphere
stone
continental crust is composed of
granitic rock
what does asthenos mean in asthenosphere
weak
what idea did the continental drift challenge?
that the earth’s continents and ocean basins had fixed geographic positions
oceanic crust is composed of
basaltic rock
the plates of the earth are apart of the
lithosphere
the longest topographic feature on earth is
the global oceanic ridge system
convergent boundaries are also called
subduction zones
deep ocean trenches are produced from
convergent boundaries/subduction zones
what is a mantle plume
a cylindrical upwelling of hot rock originating from the mantle
how did we confirm the ocean floor’s youngest at the ridge axis?
deep sea drilling
what are hot spots general position
relatively fixed within the mantle
if a plate moves over a hot spot, what is created?
a hot spot track
an example of a hot spot track
hawaii
the threshold temperature for magnetism
curie point
what is slab pull?
subduction of slabs of oceanic lithosphere
What is the process that occurs along oceanic ridges where newly formed oceanic lithosphere is being pushed away from the ridge axis?
ridge push
