Continental Drift Flashcards
Who said that the continents were in one landmass and gradually drifted apart?
Alfred Wegener
What were Wegener’s three main pieces of evidence of continental drift?
fossils (Mesosaurus), climate (Greenland), geology (rock layers in S.America and Africa)
What is the supercontinent named?
Pangaea
Why was Wegener’s hypothesis rejected?
Because he couldn’t explain HOW the continents moved
What is the process where new ocean floor is being made and old floor is destroyed?
Sea floor spreading
Where is the youngest ocean floor?
Closest to the mid ocean ridge
Where is the oldest sea floor destroyed?
At a deep ocean trench
What is the reason Arthur Holmes discovered for the movement of continents?
Convection currents
Explain a convection current in the mantle.
Hot, soft rock in the asthenosphere rises, cools, then sinks, then is heated again. This continues over and over.
What are the three main sources of thermal energy transfer in the Earth?
Radiation, Conduction, Convection
What does the theory of Plate Tectonics state?
The Earth’s lithosphere is made up of huge plates that move over the surface of the Earth.
