ERTH 1050 - Plate Tectonics

What is “slab pull”?

The crust that is being subducted

What is viscosity?

How much something behaves like a liquid (high = honey, low = water)

What does the Wilson Cycle refer to?

The cycle every plate boundary goes through during continental drift

What is mafic rock made of?

only mantle material

What is felsic rock made of?

Mantle material, silicates, sediment, organic matter, and water

What do divergent boundaries make?

Mid ocean ridges (oceanic crust), rift valleys (cont. crust), fissures

What do convergent boundaries make?

Mountains (cont), volcanoes, subduction zones, and trenches

What do transform boundaries cause?

Earthquakes and fault lines

What drives mantle convection?

Subduction and the emission of mantle plumes

What is the first stage of the Wilson Cycle?

Embryotic

2nd stage of the Wilson Cycle?

Juvenile ocean

3rd stage of the Wilson cycle?

Mature ocean (ex/ Atlantic Ocean: no subduction on any side)

4th stage of the Wilson cycle?

Declining ocean (ex/ Pacific ocean: subducts on all sides)

5th stage of the Wilson cycle?

Terminal ocean (ex/ Mediterranian ocean (continuously shrinks and continents come close together)

6th stage of the Wilson cycle?

Suturing

What happens in the embryotic stage of the Wilson cycle?

Plate gets too heavy; rift begins to happen as the continental plate splits via divergent boundary

What is a juvenile ocean?

An increasing rift due to continental plate divergence. Begins to fill with oceanic crust (birth of new ocean)

What is a mature ocean?

An ocean that has established oceanic crust that is not subducting actively in any direction

What is a declining ocean?

An ocean whose oceanic plate is subducting on one or more sides, causing it to shrink

What is a terminal ocean?

An ocean that continues to shrink and continental plates approach each other. Oceanic plate continues to subduct

What is suturing?

Plate collision that closes an ocean entirely

Why do continental plates not usually subduct?

They are less dense, and thus “float” higher over the mantle

Oceanic crust is ____, ___, and ____ than continental crust

thinner, denser, younger

What creates oceans? What plate boundary is associated with that process?

Rifts, divergent

What is continental drift?

The concept that all of the plates are constantly drifting farther away from each other in cm/yr

Examples of proof for continental drift?

Land dwelling animals and plants being found in locations that are not separated by oceans