Continental Drift and Plate Tectonic

What is the Theory of Continental Drift?

• New continents are continually being created

  and destroyed.

• The layout of the continents is the same today

  as it has always been

• The continents have always been separate but

  may one day drift together to form a single

  continent

• All the continents were once one continent that

  broke up and drifted apart over hundreds of

  millions of years

Alfred Wegener proposed the Theory of Continental Drift. Which one of these does NOT support the theory Wegener proposed?

• Fossils that were similar were found on different continents.

• Bacteria was found all over the world.

• Shape of continents fit together to form a supercontinent called Pangea

• Climate seen as glacial or ice sharring are found all over the world.

Why was Alfred Wegener unable to explain his theory?

• He couldn't explain how the continents drifted.

• He couldn't explain why similar fossils on different continents were separated

• He couldn't explain why similar geological structures found were found on different continents.

• He couldn't explain why the continents fit together like a puzzle.

If you took rock samples from the Mid-Atlantic Ridge, the youngest rock would be

• located where the plates collide

• located at the place where rocks are furthest from the rift valley

• Located at the center of the ridge (rift valley), where oceanic crust is formed

• none of the above; all the rocks would be the same age

Tectonic plates float on top of the

• crust

• asthenosphere

• lower mantle

• outer core

What process is responsible for moving Earth's plates?

• convection currents in the outer core
• ^{convection currents in the inner core}
• convection currents in the mantle
• conduction currents in the lithosphere

Earth's lithospheric plates move at a rate of a few _____________ every year.

• centimeters

• miles

• kilometers

• yards

What are the two types of crust?

• continental and oceanic
• ocean and basin
• lower and upper
• thick and thin

The geological theory that states that pieces of Earth's lithosphere are in constant, slow motion is the theory of

• subduction
• plate tectonics
• evolution
• seafloor spreading

What evidence helped Harry Hess prove that sea-floor spreading was occuring

• Ocean crust gets older as you move away from mid ocean ridges

• Underwater mountains

• Fossils of plants and animals

• Puzzle fit of the continents