Chapter 25 Flashcards
a system of mountain ranges on the seafloor separated by valleys
Mid- Ocean Ridge
forms in between peaks along the mid-ocean ridge
Rift Valley
where two plates collide
convergent plate boundary
a thick and buoyant continental plate meets a tin and dense oceanic plate, the denser plate dives beneath the continent in a process
subduction
boundary between two plates that are moving apart
divergent plate boundary
type of boundary where plates slide horizontally past each other in opposite directions
transform plate boundary
is the sudden movement or vibration of the ground occurs when rocks slip/slide along enormous cracks in Earths crust called faults
earthquake
is a crack in Earths crust along which rock has moved
fault
the sudden release of strain energy as rocks moves along a fault
elastic rebound
the point of origin for an earthquake
focus
the point on on Earths surface directly above the focus
epicenter
Who came up with the continental drift hypothesis?
Alfred Wegener
What where some of the evidence that backed up his hypothesis?
- large land animal fossils
- cost lines matched up like puzzle pieces
- mountain ranges matched up with the same rock type and ages
What was the name of the super continent?
Pangaea
Who came up with the seafloor spreading hypothesis?
Harry Hess
How did he discover the seafloor spreading?
Sonar
Who discovered the mid- ocean ridge? (MOR)
Harry Hess
What are the 3 types of plate boundaries?
- convergent plate boundary
- divergent plate boundary
- transform plate boundary
How do convergent plate boundaries move?
together
Subduction zones only happen with which type of plate boundary?
Convergent plate boundary
What two types of crust are used for plate
boundaries?
- Oceanic Crust
2. Continental Crust
what two types of of land forces can be created from oceanic crust and continental crust?
- Volcanoes
2. deep- sea trench
What land forms can form when two oceanic crusts converge?
- deep-see trench
2. hot spots
What is created when two Continental crusts converge?
mountains
How do divergent plate boundaries move?
divide from each other
What are some examples of divergent plate boundaries?
- mid- ocean ridge (MOR) (both oceanic)
2. East African rift (two continental crusts)
How do transform plate boundaries move?
slide past each other
What is a specific example of a transform plate boundary?
San Andrea Fault (continental crust)
What is a convection current?
- magma heats up, becomes less dense, and rises
2. magma cools, becomes more dense, and sinks
What are three forces to contribute to plate motion?
- slab pull
- ridge push
- friction
