U3L2

Question 1

state the theory of plate tectonics

Answer 1

the theory that describes large scale movements of parts of earth’s crust called tectonic plates

Question 2

how was the theory of plate tectonics developed? what were the three pieces of evidence for it?

Answer 2

Alfred Wegener proposed the theory in the late 1800’s. evidence:
- rocks & fossils: same species found on separate sides of the Atlantic
- shape of continents: locations of mountains & rock formations suggest previous connection
- climatic evidence: evidence of ancient climatic conditions from things like coal deposits and past glacial activity

Question 3

list & describe three mechanisms of plate movement.

Answer 3

• mantle convection: convection currents in mantle magma move the plates
• slab pull: oceanic lithosphere builds on coastline and deserve plate sinks into the mantle pulling the rest of the slab down with it (convergent boundary)
• ridge push: rock from rift slides down ridge and pushes old rock in front of it (divergent boundary)

Question 4

define subduction

Answer 4

the process by which one tectonic plate is pulled beneath another plate