Definitions
Where two plates meet each other
Boundary
Who came up with the theory of Pangea?
Wegener
Why was Pangea's idea only a theory at the time?
Technology limited his ability to find evidence
Which type of mapping was used when mapping the seafloor?
Topographic
How many plates are there in the world?
20
The part of the Mantle broken up into plates
Lithosphere
Who came up with the theory of Seafloor Spreading?
Hess
Anchor weights and ropes
Which type AND subtype of rock comes from divergent boundaries?
Extrusive Igneous Rock
What are the two types of tectonic plates?
Oceanic and Continental
The part of the Mantle responsible for Convection and plate movement
Asthenosphere
Which technology was responsible for accurate seafloor mapping, and which war created a need for that technology?
Sonar, WWII
What are the 3 types of boundaries?
Transform, Divergent, Convergent
Which part of the rock cycle is most closely related to seafloor spreading?
Melting of rock material into igneous rocks
Which boundaries destroy plate material?
Convergent
When two plates separate and form a trench
Divergent Boundary
The ocean floor is growing/spreading by about _____ per year?
2 cm
What are the 3 pieces of evidence that seafloor spreading is correct?
Temperature of water is higher
Age of Igneous Rocks is younger than those around it
Sea landscape is changing
If the sea floor can move, so can the continents
Which boundaries create plate material?
Divergent
When _________ plates crash into __________ plates and the __________ plate dives into the mantle, melting away
Continental, Oceanic, Oceanic
SUBDUCTION
About what temperature is the Mantle and the Magma leaving it?
2,000 F
True/False: New plates are added/taken away to the Mantle all the time
False
New PIECES of plate
Explain Seafloor Spreading
Divergent boundaries create trenches where the Mantle leaks Magma. That Magma cools into Igneous Rock, creating new parts of plate and expanding the ocean floor
What is the name of the ocean that originally surrounded Pangea?
Panthalassa