Lecture 4// Plate Tectonics Part II

Question 1

Hot spots (5)

Answer 1

• Develops above a mantle plume.
• Magma generated by the hot spot rises through the rigid plates of lithosphere and produces active volcanoes at the surface.
• Volcanism punches through the overriding plate producing a chain of volcanoes that will increase in age with distance from the active hot spot.

Example at plate boundaries:

• Iceland Hot Spot
• Galapagos Hot Spot

Example at mid-plate:

• Hawaiian Hot Spot
• Yellowstone Hot Spot

Question 2

3 Convergent plate margins

where plates come together) (3

Answer 2

Oceanic-oceanic:
The older, denser oceanic plate subducts.

Oceanic-continental:
-The oceanic plate subducts as it is denser and thinner.

Continental-continental:
-Neither subducts and thus buckling occurs.

Question 3

Oceanic-oceanic plate convergence (3)

Answer 3

• An island arc of volcanoes form.
• Water in the subducted oceanic lithosphere is heated and turned into water vapor.
• The rises into the overlying asthenosphere and lowers the melting temperature of the rock resulting in partial melting.

Question 4

Oceanic-continental plate convergence (1)

Answer 4

-Water also results in partial melting, but the chain of volcanoes is on land and not as islands - called volcanic arc.

Question 5

Continent-continent collision (1)

Answer 5

-Extreme deformation (faults & folds) and crustal thickening occurs in the sutured area.

Question 6

Pacific Ring of Fire (1)

Answer 6

-The Pacific Ocean sees seafloor spreading along the East Pacific Rise, but loses seafloor to subduction to PRF

Question 7

Transform Plate Margins (1)

Answer 7

-Locations where tectonic plates slide past each other along one or more transform faults. (Can involve o-o, o-c, or c-c)