Plate Theories

Question 1

Continental Drift

Answer 1

Developed by Alfred Wegener in 1912. He suggested that the world’s crust consists of plates that constantly move on the mantle. South America and Africa fit together almost perfectly. All land masses were originally 1 super continent (Pangaea). Proof: continental fit, matching plant and animal fossils

Question 2

Convection Currents

Answer 2

Discovered in 1928 by Arthur Holmes. Convection currents cause plates to move. Magma heats, rises and moves towards the upper mantle. The magma then flows sideways, cools and becomes semi - molten rock before sinking.

Question 3

Mid - Ocean Ridges

Answer 3

Discovered by Maurice Ewing in 1947. He discovered a chain of underwater volcanoes along the middle of the Atlantic Ocean. This is known as the Mid Atlantic Ridge.

Question 4

Sea floor Spreading

Answer 4

Discovered by Harey Hess in 1962. He explained that mid - ocean ridges were points where new sea floor is created. The North American Plate and Eurasian Plate began to separate 60 million years ago creating the Atlantic Ocean