GE CLST 70A Lecture Notes - Lecture 18: Runaway Greenhouse Effect, Hydrosphere, Deuterium
23 Jan 2017
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Seafloor is being made today @ mid-ocean ridges and gets older in a symmetrical fashion with distance away from the ridge. Evidence for plate tectonics: trans-oceanic plants and fossils. Identical rock formations on different continents: paleomagnetism, ocean island chains showing the motion of the oceanic plate over a hot spot in the mantle, location of earthquakes and volcanoes along plate boundaries. In many places in the oceans, long chains of volcanoes appear. Many of these are large enough to emerge as islands (hawaii, for example) The hawaiian islands get older from west to east. Can also be rift valleys on land, which will become mid-ocean ridges after the plates have spread apart enough: e. g. Juan de fuca plate, cascades, coast of japan, sumatra-java: ocean-ocean subduction crease arcs of volcanic islands, e. g. Continent-continent convergent boundaries: raises very high mountains, e. g. Generally doesn"t create topography because the slip vector is side-to-side, not up-and-down.
