1.4 Hot Spots

Plates move, not the hot spot. 

• When land is dragged off hot spot because the plate moved, the land sinks. As the rocks get colder, the less buoyant they are leading them to sink. 

Hot spot hypothesis 

• Volcanically active regions located from plate boundaries 

  • Examples include Hawaiian islands, Yellowstone 

• Fixed plumes of magma rising from the mantle; a blow torch underneath the plates 

Measure the plate tectonics' motion 

• Geomagnetic reversal, GPS, and transform faults 

Accretion: how continents grow 

• At a subduction zone, continental fragments can collide and stick to continents 

• Forms mountains 

• India was accreted into asia, formed himalayas 

• 70% of western North America formed by accretion