Earth Structure and Atmosphere Flashcards
What was the old explanation for fossils on opposite sides of the Atlantic Ocean?
Land bridges that have been covered since.
What was the evidence that Alfred Wegener noticed?
- Continental coastlines fit together
- Matching layers of rocks in different continents
- Fossils in the wrong places (e.g tropical plants in Arctic islands)
What was Wegener’s theory called?
Continental Drift.
Why wasn’t Wegener’s theory accepted?
He couldn’t explain why the continents were moving
or
There wasn’t enough/any evidence
Why is the mantle hot?
Radioactive decay.
Why does the mantle flow?
Convection currents, from the heat of radioactive decay.
What is the core of the Earth made of?
Iron and nickel.
What is the top layer of the earth?
The crust.
What often occurs at the boundaries of two plates?
Volcanoes and earthquakes.
What are earthquakes caused by?
Sudden movement of tectonic plates.
Why are earthquakes impossible to predict?
Tectonic plates move suddenly.
Why was there no atmosphere on early Earth?
The Earth’s surface was molten, so any atmosphere boiled away.
Where did the early atmosphere come from?
Volcanoes.
What was the early atmosphere made up of?
Mostly CO2, some water vapour, and small amounts of methane and ammonia.
How were the oceans formed?
Water vapour condensation.
