Unit 8: Plate Tectonics Review

Which types of evidence supported continental drift?

• Land features - mountain ranges, coal deposits

• Fossils - fern like plant (Glossopteris) found on 5 continents, Mesosaurus fossils found in same type of rock in both South America & Africa

• Climate - continents have evidence of having climates that cannot be supported now

• All of the above

Which of the following is NOT a plate boundary?

• Divergent boundary - plates move apart, creates mid-ocean ridges & rift valleys, can release molten material to form volcanic islands

• Convergent boundary - plates come together, create mountains or volcanoes, oceanic crust always goes under continental crust

• Transform boundary - plates slip past each other, fault ruptures and an earthquake occurs

• Plate Tectonics - plates stay together to make up Earth's Crust

Which of the following are NOT types of stress?

• Tension - pulls or stretches on Earth’s crust

• Compression - squeezes rock until it bends or breaks

• Shearing - occurs when rock is being pushed in 2 opposite directions

• Stretching - pulling on Earth's layers

How do mountains and valleys form from a series of normal faults?

• A foot wall slips down to form a valley at a convergent plate boundary. Rock on either side of the valley becomes the mountains.

• Walls of rock grind past each other in opposite directions. This pushes one side up above the other to form the mountains.

• Compression causes rock to fold and bend, but not break, in the middle of a plate. The rock that folds upward becomes a series of mountains.

• A hanging wall slips down at a divergent plate boundary. The slab of crust that falls forms a valley, and the slabs on each side form mountains.

Compare & contrast normal, reverse, and strike-slip faults.

• Normal - footwall slides down the hanging wall, Reverse - hanging wall slides up over the footwall, Strike-slip - rock walls grind past each other in opposite directions.

• Normal - hanging wall slides down the footwall, Reverse - footwall slides up over the hanging wall, Strike-slip - rock walls grind past each other in the same direction.

• Normal - rock walls grind past each other in opposite directions, Reverse - footwall slides down the hanging wall, Strike-slip - hanging wall slides up over the footwall.

• Normal - hanging wall slides up over the footwall, Reverse - rock walls grind past each other in opposite directions, Strike-slip - footwall slides down the hanging wall.

What does the magnitude of an earthquake measure?

• The size of the earthquake’s seismic waves

• The energy released by the earthquake

• The damage done by the earthquake

• The length of the earthquake

Earthquakes or landslides can create tsunamis by:

• displacing large volumes of water

• increasing water temperature

• changing water salinity

• altering ocean currents

What might happen to the activity of an active volcano if the subducting plate stops moving?

• It would grow more intense

• It would slow down, and the volcano might become dormant.

• The lava would have more silica, leading to more violent eruptions

• It would remain the same.

If plates were moving around because of convection currents, don’t some of them crash into each other? Which of the following is a partial explanation that can answer the question and is supported by an Earth model.

• Yes, they do get stuck for a long period of time

• Plates that collide wear down at their edges becoming rubble and sediment.

• The plates that collide get compressed

• Some plate edges subduct, or dive under other plate edges.

How do active, dormant, and extinct volcanoes differ?

• Active volcanoes erupt often, dormant volcanoes could erupt in the future, and extinct volcanoes are not expected to erupt again.

• Active volcanoes never erupt, dormant volcanoes erupt often, and extinct volcanoes erupt occasionally.

• Active volcanoes are always erupting, dormant volcanoes are extinct, and extinct volcanoes are dormant.