GEO 1111 Lecture Notes - Lecture 6: Asthenosphere, Seafloor Spreading, Subduction

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: Robert Jack Cornett

Document Summary

Driving force for plate tectonic is sea floor spreading and subduction. Plate goes under the continent cycles back to the mantle then volcanism goes back up. Earthquake all occur in and above upper mantle. New crust is created but the earth is not getting larger. Mantle convection may be the cause or an effect for circulation set up by. Slab push pushing of crust resulting from elevated position of oceanic ride system causing crust to gravitationally slide down flanks of ridges. Slab pull pulling of crust into mantle by down-going slab during subduction. Continental crust thicken as theres movement: tuzo wilsons plate model. Tectonic plate are composed of the relatively rigid brittle lithosphere. Plates interacts at their boundaries which are classified by relative plate motion. Type 1 margin divergent margin: plates move away from each other, can occur within continent always leads to creation of ocean basin. Normal faults mark rift zones, decompression causes melting.