Continental Drift Flashcards
What did geologists believe about the Earth in the 1800’s?
The Earth cooled and the crust began to shrink and wrinkle.
How was the shrinking theory used to describe the landscape?
Continent were the high parts of the wrinkles and oceans covered the lower parts. This also explains mountains and valleys.
According to the shrinking theory, how did the Earth begin?
As a molten blob which gradually cooled. Metals adjusted their position in layers of the Earth based on their density and weight. Contraction pressure caused the crust to buckle upwards and downwards forming mountains and ocean basins.
When was evidence discovered that continents were moving?
Late 1800’s and early 1900’s
What did geologists believe about the location of volcanoes, earthquakes and mountains in relation to the shrinking theory?
Their locations are random.
How did the continents exist millions of years ago according to the continental drift theory?
They started as a large supercontinent then broke into smaller parts.
Who proposed the continental drift theory and in what year?
In 1912 Alfred Wegener proposed the continental drift theory.
What relation did Alfred Wegener make between the continents.
They would fit together much like a jigsaw puzzle.
How did Wegener explain the ‘drifting’ of the continents?
They were floating on a denser material underneath them.
What was the name of the super continent and the ocean that surrounded it according tot he continental drift theory?
Continent: Pangea
Ocean: Panthalassa
What did Du Toit name the northern and southern parts of Pangea?
Laurasia and Gondwana
How do fossils prove the continental drift theory?
The same fossils of plants and animals could be found on different continents.
What did Wegener propose about the placement and formation of mountains?
They were formed when the edge of a drifting continent collided with another causing it to crumple and fold.
