Test Review. The hypothesis that continents slowly move across Earth’s surface.

Plate TectonicsTest Review

What is CONTINENTAL DRIFT?• The hypothesis that continents slowly move

across Earth’s surface

What evidence supports CONTINENTAL DRIFT THEORY?• Landforms – mountain ranges that match up along

different coast lines• Fossils – fossils of the same organism have been

found on different continents• Climate – Climate has not changed over time

Wegener’s supercontinent was called…• Pangaea

Why was CONTINENTAL DRIFT not widely accepted?• Because Wegener could not provide a mechanism

for HOW the continents moved• He could not explain why mountains formed in the

middle of continents

What features occur at DIVERGENT BOUNDARIES?• Rift valleys• Deep-sea trenches

What features occur at OCEAN-OCEAN CONVERGENT BOUNDARIES?

• Deep-sea trenches• Island arcs• Subducting plate

What features occur at OCEAN-CONTINENT CONVERGENT BOUNDARIES?

• Trench• Volcanic mountain range• Oceanic subducting plate

What features occur at CONTINENT-CONTINENT CONVERGENT BOUNDARIES?

• Folded mountain range

What features occur at TRANSFORM (SLIDING) BOUNDARY

• Trenches• Faults• Fracture zones• Earthquakes

Describe what happens to crust (created, destroyed, etc.) at each of the three major boundaries.• Divergent – created• Convergent – destroyed• Transform – neither created nor destroyed

Give an example of each type of boundary.• Transform – • San Andreas Fault

• Continental-Continental Divergent – • East African Rift Valley

• Ocean-Ocean Divergent– • Mid-Atlantic Ridge

• Ocean-Ocean Convergent – • Mariana Trench

• Continental-Continental Convergent – • Andes Mountains

What produces plate movement?• Convection currents in the mantle• Slab pull• Ridge push

Where are the youngest rocks in the ocean floor located? Why?

• The mid-ocean ridge• It’s where sea-floor spreading occurs

What are the four layers of the Earth?• Crust• Mantle• Outer Core• Inner Core

Which layer of the Earth is thinnest? Thickest?• Crust• Mantle

Which plate is the largest?• Antarctic

Which ocean is shrinking? Which is growing? WHY?• The Pacific is shrinking because of the large deep

ocean trenches.• The Atlantic is growing because of the large Mid-

Ocean Ridge.

What area do we find the most volcanoes and earthquakes?

• Ring of Fire

What are the major types of volcanoes?• Shield• Cinder cone• Composite• Hot spots

Along what boundary do volcanos occur?• Convergent boundaries