Continental Drift
Were the continents always in the same position as today?
No
What 3 new discoveries were made in the Mid-1900s?
Seafloor spreading, magnetic stripping, structure of earth's interior
What are tectonic plates made of?
Continental crust, oceanic crust, uppermost mantle
What is a plate boundary?
Where two tectonic plates meet.
What is the largest unit of geologic time?
Eons
What are the 3 pieces of evidence used to support the theory of Continental Drift?
Fossils, Coastline, Rocks & Mountains
What is seafloor spreading?
Mid-ocean ridges where new crust forms and moves outward.
Describe the Lithosphere.
Rigid, broken into plates.
What are the 3 types of plate boundaries?
Convergent, divergent, transform
What is the smallest unit of geologic time?
Epochs
What did Wegener's evidence suggest?
Continents were once connected & continents have moved overtime.
What is magnetic striping?
Patterns that showed the seafloor was spreading over time.
Define the Theory of Plate Tectonics.
Earth's lithosphere is broken into plates that move over the asthenosphere.
How do plates move at a convergent boundary?
Toward each other.
What is the geologic time scale based on?
The unique characteristics of fossil species.
What was the missing piece of Wegener's theory of Continental Drift?
How did the continents move?
True or False: Continents move alone.
False
What 5 things does plate tectonics exaplain?
Earthquakes, volcanoes, mountains, ocean basins, age of earth's crust.
How do plates move at a divergent boundary?
Away from each other.
What is an index fossil?
Fossils used to determine the relative age of rock layers.
Why did other scientists reject Wegener's theory of Continental Drift?
Because they felt his explanation was incomplete.
How do tectonic plates move?
They move on top of the asthenosphere.
What drives plate tectonics?
Mantle Convection
How do plates move at a transform boundary?
Slide past each other.
What are the 3 key requirements to be an index fossil?
Lived for a short time, had a wide geographic distribution, easy to identify