EESA06H3 Lecture Notes - Lecture 4: Subduction, Ophiolite, Hot Press
Document Summary
Supercontinent cycle 1 continent (supercontinent) split up then we form oceans continents form apart oceans die. Cascading earthquakes the position of the earthquake gets closer and closer to the city. Istanbul is threatened by what is going on in east africa. What is happening on the surface is driven by what happens down in the middle. The core does rotate at a slightly different velocity than the mantle. How plates move: by sliding across the asthenosphere. Basalt: is a very important rock type produced at mid-ocean ridges; principle component of oceanic crust; Asthenosphere (is low-velocity zone); the weak sphere; allows these relatively rigid plates to move around the planet. Lithosphere: means rocky sphere; this is on top of the asthenosphere. Start off with cracks those cracks are called rifts. They broke up precisely because there was a plume underneath. You have to have huge plumes feeding this mid ocean ridges otherwise the oceans don"t widen.
