PHYSICS 20E Lecture Notes - Lecture 9: Shocked Quartz, Kinetic Energy, Earth Mass
Document Summary
Where plates move toward each other, one can slip under the other (subduction) Tsunamis can form in areas where plates can subduct: sea-floor abruptly deforms, shocking the water. Divergent boundaries are where two plates are moving away from each other. New crustal rock is created at the junction. Hot spots can form in the middle of a plate, building chains of shield volcanoes as the plate slides over it. The earth is a dynamic, evolving planet. The earth"s surface has been reshaped by tectonic and weather forces acting over billions of years. Most of the surface is relatively young (few 10s to 100s of myr) It is still active today because its interior is still hot, most (80%) of the heat coming from radioactive decay. Earth"s tectonic activity may be an important factor in its habitability. The four eons are the major divisions of geological time. Before life, coincides with late heavy bombardment .
