Plate Tectonics Flashcards
When was the continental drift idea proposed?
1915
Who proposed the continental drift idea?
Alfred Wegener
Wegener’s first proof
Similarity of Coastlines
Weneger’s second proof
Mountain Ranges on separate coasts
examples of mountain ranges on separate coasts 1
Appalachians and mountain ranges in Ireland and New Britain are the same
examples of mountain ranges on separate coasts 2
The Cape of Good Hope and the southern tip of Africa contain the same rock type, same foundations, minerals, and structures
Wegener’s third proof
Fossils of similar animals on separate coasts
Dinosaur fossils are
found on every continent
Mammal fossils are
not found on every continent
would mammals or dinsoaurs migrate?
mammals
how did dinosaurs end up on every continent if they don’t migrate?
the continents had to be together in order for them to migrate from place to place
Wegener’s fourth proof
Paleoclimates
what do coal deposits in antarctica indicate?
a warm, swampy environment
Wegener’s fifth proof
Modern animals
what does the strange evolutionary pattern of marsupials indicate?
it indicates an isolation from other land masses after a certain point in evolution
Wegener’s sixth proof
Glaciation
Why did Wegener’s theory fail?
There was no way to prove how the continents moved
Why did Wegener’s theory fail?
There was no way to prove how the continents moved
What are other ideas opposing Wegener’s?
Rafting, Island stepping stones, Isthmian links
Wegener’s ideas went cold until-
World War 2 submarines
While searching for submarines, what happened?
the sea floor was inadvertently mapped by sonar
what fueled the idea of continental drift?
the discovery of the mid atlantic ridge
what are the dimensions of the mid atlantic ridge?
40,000 miles long, 1,500 miles wide, 2 miles high
why is the mid-Atlantic ridge so intriguing?
it lies in between the continents, almost equidistant from each shoreline
