CH 25 and CH 26 Flashcards
a system of mountain ranges on the seafloor separated by valleys
mid-range ridge
a long narrow depression forms in between peaks along mid-range ocean ridge
rift valley
the boundary where two plates collide
convergent plate boundary
when a thick and boundary continental plate meets a thin and dense oceanic plate the denser plate dives beneath the continent in a process
subduction
the boundary between two plates that are moving apart
divergent plate boundary
this type of boundary where plates slide horizontally past each other in opposite directions
transform plate boundary
a sudden movement or vibration of the ground that occurs when rocks slip and slide along enormous cracks in Earths crust called faults
earthquake
a crack in Earths crust along which rock has moved
fault
this sudden release of strain energy as rock moves along a faults
elastic rebound
the point of origin of an earthquake
focus
the point on Earths surface directly above the focus
epicenter
who came up the Continental drift hypothesis
Alfredo Wegener
what are some evidence for the Continental drift hypothesis
- the continents matched up like a puzzle piece
- Mountain ranges with the same rock type
- found large animals fossils
what was the name of the super Continental
Pangaea pangaea
who came up with the seafloor spreading hypothesis
Harry Hess
how did Harry Hess discover the seafloor spreading
He used sonar
who discovered the MOR
Harry Hess
on the ocean floor where is the newer rock formed
closer to the MOR
what are the 3 plate boundaries
- Divergent plate boundary
- Convergent plate boundary
- Transform plate boundary
how do convergent plates move`
they collide together
subduction only happens with what type of plate boundary
convergent plate boundary
what types of crust do we have?
Continental crust and Oceanic crust
what type of crust has to be present for volcanic activity to occur
oceanic crust
if two Continental crust collide what will happen
a mountain will be made
if oceanic and continental crusts converge what two land forms will be created
deep sea trench and volcanoes
what can be created when two oceanic crusts converge
a oceanic island and maybe deep sea trench
what do hot spots create
volcanic islands
how do divergent boundaries move
they move away from each other