Past Ecosystems Flashcards
What causses the continents to collide, join together, or move around?
Tectonic plate movement.
When is it estimated that Gondwana split up?
The Jurassic period, around 182 million years ago.
Which continents formed the supercontinent Gondwana?
South America, Africa, India, Antarctica, and Australia.
How long ago was Pangaea around?
250 million years ago.
What radioisotopes are used to help date ice cores?
Uranium-238 and Uranium-234
Where does the most ice drilling occur?
Antarctica and Greenland
How many years of data can ice drilling provide?
Over 800,000 years ago.
How are precipitation rates determined from ice core samples?
Thickness of annual layers.
What isotopes help determine historic temperatures?
Deuterium and Oxygen-18
What technology is used to measure isotopes in water molecules?
Mass spectometry.
Why are gas bubbles so important in ice core drilling?
They are samples of the atmosphere at the time the ice layer formed. They can be used to determine past temperatures and greenhouse gas concerntration.
What is the relationship between temperature and atmospheric carbon dioxide concerntration?
As temperature increases, so does atmospheric carbon dioxide concerntration.
When did Australia and Antarctica separate?
40-50 million years ago
