Lecture 3 Flashcards
What is the lithosphere?
The lithosphere is th router part of the Earth
What does the lithosphere consist of?
Consists of the crust and upper mantle
What is the asthenosphere?
upper part of mantle
Describe the asthenosphere in terms of flow.
Thought to be able to flow vertically and horizontally.
What acts like a conveyor belt? Why?
- the asthenosphere
- because of plate tectonics
What is the outer core thought to be composed of?
mostly nickel and iron
What is thought to be slightly viscous, creating turbulence?
the outer core
What is the outer core responsible for?
Responsible for earth’s magnetic field, which deflects solar radiation.
Who first propose the theory of continental drift?
Alfred Wegener (1915)
What is continental drift? What was it based on?
- idea that continents moved about the face of the planet
- primarily was based indirect evidence
What was the evidence for continental drift?
Early scientists recognized relationship between fossils on continents separated by sea.
- Proposed land bridges
What is Pangaea?
The supercontinent proposed by Wegener, which broke apart around 200 million years ago.
What are 2 points of evidence for continental drift across the Atlantic Ocean?
1) Fit of continents
2) Fossil evidence
What is ‘fit of continents’?
In particular, recognized South America and Africa, as well as India and Antarctica could be reconstructed as fitting together.
What are 4 points about fossil evidence?
1) Glossopteris flora present only in southern hemisphere continents
2) Cynognathus, a predatory mammal-like reptile, has been recovered from deposits in Africa and South America
3) Lystosaurus, a herbivore recovered from Triassic aged rocks in Africa, India, and Antarctica
5) Mesosaurus, a crocodile-like reptile, had been found in both Brazil and Africa
