Dynamic Earth Lecture 1 Flashcards
Who proposed the theory of continental drift?
Alfred Wegener
What is the continental drift theory?
The theory that the continents are in constant motion on the surface of the Earth.
What is Pangaea?
A supercontinent that incorporated almost all the landmasses on Earth.
What is the evidence for the continental drift theory?
Rock formations, glacial grooves, coal deposits, and fossils.
Describe the evidence from rock formations.
Rock formations and mountain ranges in Australia, South America, Africa, India, and Antarctica were formed at the same time and same way.
Ex. The Caledonian mountain range in Northern Europe and the Appalachian Mountains in Eastern North America
Describe the evidence from glacial grooves.
Wegener found glacial grooves on many continents in the direction that the ice sheet moved across Pangaea.
Describe the evidence from coal deposits.
Antarctica has coal deposits, which means it was close to the equator in the past and had a warm and wet climate.
Describe the evidence from fossils.
The fossils of the plant Glossopteris have been discovered from South America, Africa, India, Antarctica, and Australia.
Why was Wegener’s theory not accepted?
He was not able to explain why continents move and how fast they were moving.
When was the ocean floor studied in detail?
In the 1940s
What did scientists use to study the underwater topography?
Sound echo (sonar - sound navigation ranging)
What are mid ocean ridges?
Undersea mountain chains that are part of a long system of mountains
Ex. Mid Atlantic Ridge, East Pacific Rise
What are deep ocean trenches?
Deep underwater troughs on the ocean floor.
Ex. Marianas Trench
