GEL Week 2- Hotspots and supercontinents (5)

Plate motion

Driving force is gravity, mainly slab pull and ridge push

Slab pull

Subducting plate pulls everything along behind it.

(old oceanic crust is dense, so it sinks)

Ridge push

HIgher elevation of MOR pushes down on new crust

How can we see which way plates are moving?

Hot spots- Volcanic plumes independent of tectonic plates

(volcanoes that are not associated with plate boundaries)

Why are hot spots important?

Hot spots reveal how plates move, the direction they move in, and the speed

Hot spot process:

1- Volcanoes form on the overriding plate.

2- Plate moves, but hot spot is stationary, so volcano goes extinct

3- New volcano forms above hot spot

4- Process repeats, forms a chain of volcanoes

Why do hotspots erode?

Hot spots eventually erode beneath waves and lack of active volcanoes

What are seamounts?

Eroded extinct volcanoes

What is the role of age in plate motion?

Age change marks direction of plate motion.

T/F: Pangea was the first supercontinent

False

Supercontinent cycle

1- Supercontinent breaks apart

2- Starts to spread apart

3- Subduction occurs, it slams together

4- Cycle repeats (every 300 to 500 mil yrs)