GEOL 106 Lecture Notes - Lecture 20: Asthenosphere, Lithosphere, Upwelling

• School: Queen's University
• Department: Geological Sciences and Geological Engineering
• Course: GEOL 106
• Professor: John Hanes

Document Summary

Plate tectonic: outer 100 km of earth is like a cracked egg-shell: the earthquake zones are where the cracks are, the ridged egg-shell pieces (plates) can slide around over the convecting mantle beneath. How thick is the plate: lithosphere (brittle sphere): is the plate that slides around on the asthenosphere. It consists of crust and mantle, and is 100 km thick: asthenosphere (plastic sphere): slides at rates of several centimeters per year (rate of fingernail growth) There are three movements of plates: diverge: move apart constructive plate merging, upwelling part of the convective cycle, new lithosphere plates are produced and move apart, new ocean crust is produced. It creates continental mountain belts (fold and faults: it creates continental mountain belts (fold and faults, it creates continental crust, continental lithosphere under continental lithosphere, close oceans, can cause the continents to collide (eventually)