What is a divergent plate boundary? Explain what happens there.
A boundary where two plates move apart. The plates move apart. Magma rises to the surface, cools, and makes new crust.
100
What happens at a fault?
The rocks slide past one another and cause earthquakes.
100
How does a volcano affect the atmosphere?
It pollutes it!
100
Who came up with the hypothesis "continental drift"?
Alfred Wegener
100
Where did they gather evidence for plate tectonics?
The seafloor: mid-ocean ridges, trenches, sea-floor spreading, the age of the seafloor, etc.
200
What is a convergent plate boundary? Explain what happens there.
A plate boundary where two plates move together.
Collision - two plates with the same density run into each other and form mountains
Subduction - two plates move together, the denser one dives under the other, and melts
200
What could happen if the earthquake happens under water?
Tsunami!
200
True or False: A volcano creates crust.
True.
200
What are the three pieces of evidence for continental drift?
Fossils, geology, and climate
200
What is subduction?
It is a convergent boundary where two plates move together. The denser one goes below the less dense plate. The one that goes under melts and is destroyed.
300
What is a transform boundary? Describe what happens there
Where two plates move past one another. No crust is created or destroyed.
300
What causes an earthquake?
Rocks slip past one another in the crust and release seismic waves (energy)
300
What causes most volcanoes?
Subduction (convergent boundaries)
300
What did Wegener call his super continent?
Pangea
300
Describe the lithosphere and asthenosphere.
Lithoshere is solid, on top, and broken into plates
Asthenosphere is liquid, on bottom, and has convection currents
400
How fast do plates move?
They continuously move very slowly
400
Where do most earthquakes occur?
Transform boundaries/Faults
400
What is a hot spot?
A spot in the mantle that is very hot. It melts a hole in the crust and forms a volcano.
400
True or False: People believed Alfred Wegener.
False!
400
What is happening to the Atlantic Ocean? Why?
It is getting bigger because it has a mid-ocean ridge in it (a divergent boundary).
500
What causes plate tectonics?
Convection currents in the asthenosphere
500
True or False: Earthquakes can occur at any plate boundary.
True!
500
What made the Hawaiian Islands?
A hot spot
500
How did Wegener's fossils support continental drift?
Animals: Land animals cannot swim across an ocean. The continents had to be together at one point
Plants: Tropical plants cannot grow in areas like Antarctica or Greenland; therefore, these places had to have been next to the equator at one point
500
What is the ring of fire and what causes it?
It is an area surrounding the pacific ocean where 80% of all active volcanoes occur. These volcanoes are caused by subduction.