Pangaea (“all land”) What proof did Wegener have to support his theory?

Alfred Wegener and his Theory

This theory of Plate Tectonics was first introduced by German scientist, Alfred Wegener in 1915.

Name the supercontinent that existed 300 million years ago believed to have been the connection of all of Earth’s current continents: Pangaea (“all land”)

What proof did Wegener have to support his theory?

1. He saw the jigsaw fit between South America and Africa.

2. He found fossils of the same plants and animals on both continents (South American & Africa) – he believed that these fossils could exist in both places only if the continents were once joined together.

3. There are mountains similar in age and structure on both sides of the Atlantic Ocean (the Appalachians in the eastern US and Canada & the Caledonian Mountains in the northern British Isles and Europe).

These mountains formed when North America collided with Europe and northern Africa (about 300 million years ago)

4. Ice sheets covered parts of southern Africa, India, Australia, and South America about 250 million years ago. This means that at one time, the continents were located closer to the South Pole because today, these places are so warm.

Why did scientists not accept this theory at the time?

Most scientists at the time (1915) did not accept Wegener’s theory about continental drifting because Wegener could not explain what force was powerful enough to move continents.

When did the theory of plate tectonics as we understand it today get developed? 1968

Who reignited interest in the theory of continental drift? A Canadian – J. Tuzo Wilson helped spark new interest in the theory of continental drift.

The plates of the earth float on a layer of hot rock called magma. The plates are constantly moving. What is likely the cause of this movement? It is likely that convection currents caused by the unequal distribution of heat within Earth’s core cause the plates to move, but no one fully understands what exactly causes plates to move.

Convection occurs when a heated fluid or gas rises and is replaced by a cool fluid or gas (which also heats up and eventually rises)

List 2 ways the movement of plates has helped shape Canada:

1. The mountain chains on the east and west coasts were formed as a result of plates bumping together.

2. The movement of plates has also played a role in forming Canada’s fossil fuels – oil, gas, and coal formed when Canada’s land mass was located in a warmer, tropical climate.