EESC BC 1001x Lecture Notes - Lecture 11: San Andreas Fault, Vulcanian Eruption, Stratovolcano
Document Summary
Plate tectonics: the grand unifying theory of geology. Theory that lithosphere (earth"s rigid outer layer) is divided into a number of crustal plates, which move over the plastic asthenosphere, these plates collide with, move away from or move past each other. Convection currents in magma cause the movement of the plates. Alfred wegener first proposed continental drift hypothesis, 1915. No mechanism to explain how this happened. Suggested everything was together 20 million years ago. Fossil evidence same kind of fossil found on two different continents. Trends that connected the two- lined up. When put continents together seems that they were together at one point. Rock evidence same rock on different continents. Since no mechanism to explain this, theory was dismissed. 1928, arthur holmes proposed that convection currents dragged two halves of original continent apart. Heat coming from interior of earth with radioactive decay from chemicals under earth. Ww2 a lot of new technology was created.