Continental Drift/Plate Techtonic Flashcards
What did Alfred Wagner come up with?
Pangaea, suggested land masses moved slowly
What were Wegner’s 5 pieces of evidence?
- Fit of continents
- Past Glaciations
- Climactic Belts
- Fossil Distribution
- Matching Geological units
Why did Wenger face criticism for this?
Weak explanation, proposed that the Earth’s spin caused the continents to plow through the ocean floor. Could not provide a driving force
Describe the lithosphere (How many plates, movement, ect)
It’s broken into around 20 tectonic plates, moves 1-15 cm/year, plates interact along their boundaries
Describe the divergent boundary
Tectonic plates move apart, lithosphere thickens away from the ridge axis, (also called, spreading boundary and mid ocean ridge)
Describe the convergent boundary
Tectonic plates move together in what is called subduction (also called convergent margin, subduction zone)
Describe the transform boundary
tectonic plates slide sideways, plate material is neither created nor destroyed (also called transform fault)
Where and how do pillow basalts form?
underwater, lava spilling into the ocean, form as meter wide “blobs”
Where can pillow basalts be found?
at the surface of “MOR”
Define hot spots & what are they made of?
plums of deep mantle material that don’t have plates, made of lower mantle mafic magmas
What do hot spots do and what do they add?
burn through plates and add lines of volcanoes to them
Define Continental Rifting
A continent is pulled apart due to tectonic forces
What happens when continental lithosphere/rift breaks apart?
Brittle upper crust faults, ductile lower crust flaws, asthenosphere rises and melts, magma erupts
What can continental rifting cause to form?
A new mid-ocean ridge
What did continental rifting lead to?
The break-up of Pangaea
