GEOG 1120 Lecture Notes - Lecture 2: Mafic, Slab Pull, Plat
Document Summary
Lecture 2: plate tectonics: structure of earth, chemical. Mantle => elements: 0, mg, si, fe; located between the core and the crust. Core => elements: fe, ni: physical. Crust = lithosphere (crust and upper mantle). Asthenosphere = (2nd layer) upper mantle; plastic (halfway between solid and liquid layer). => has an ability of magnetic field - protective properties. Most plates have both continental and oceanic crust. Plates in motion can trigger earthquakes and they are very deadly plates. Also called as constructive boundary (new young rocks are being formed; making new rocks). Ex: the great reef in africa (rift valley). Chemistry of rock is similar to mafic crust. Two plates moving away from each other. Can also occur on continents that cause a line of volcanoes to emerge: convergent plate boundary. Continental crust floats, oceanic crust is denser thus, it sinks. Subducting oceanic lithosphere moves (goes down, melts and get recycled.
