Plate Tectonics Flashcards
How thick is the crust?
It is thin (5-32 km)
Cool, rigid & brittle
What is the mantle like?
Weak & Plastic in the upper layer
What is the outer core like?
Liquid
What is the inner core like?
Solid
What was the name of the supercontinent?
Pangaea
What evidence is there that indicates that Pangaea existed?
- Matching mountain ranges
- Fossils of extinct animals found on opposite sides of the Atlantic
- Fossil palm trees in Arctic
- Coal deposits in Antarctica
What is the study of earth’s ancient magnetic field called?
Paleomagnetism
What is polarity?
The directional orientation of the magnetic field
What did magnetic anomalies prove regarding the seafloor?
Seafloor spreading
What polarity does new oceanic crust have?
Normal polarity
What happens when the periodic shift of the magnetic field occurs in relation to the crust?
The polarity of new crust will become reverse polarity
What does the theory plate tectonics help account for?
- Volcanoes, faults and earthquakes
- Origin of ocean floor features
- How ocean floor is made
- Biogeography
Describe oceanic crust
Rich in iron and magnesium
More dense
Describe continental crust
Rich in silica and aluminum
Less dense
In what ways have plate tectonics influenced the ocean environment?
- Shaped the topography of the oceans and continental margins
- Influenced the circulation of currents and tides
- Deposited resources that drive productivity
- Resulted in established weather and climate systems
