GEOLOGY 1 Lecture Notes - Lecture 13: Continental Crust, Volcanic Arc, Oceanic Crust
Document Summary
New lithospheric plates are produced and move apart. E. g. red sea, mid-atlantic ridge (oceans open!) Destructive- come together o the piece that goes down is always the oceanic crust because it is heavier than continental crust (it gets dense by cooling) o it sinks down and forms a trench. Trenches: where oceanic lithospheric plates are subducted o. Lithospheric plates are destroyed as plates collide o types: Oceanic lithosphere under oceanic lithosphere (creates volcanic island arcs) Oceanic lithosphere under continental lithosphere (creates continental volcanic arc, continental mountain belts, continental crust) Continent-continent collision (close oceans, cause continents to collide, e. g. india collided with europe and created himalayan mountains) Transform- slide past one another o lithospheric plates slide horizontally past each other. 10% at depths between 100 and 700km. Earthquakes that occur away from a plate. Represent only about 1% of all earthquakes. St. lawrence/ ottawa valley rift zone mississippi river rift zone.
