GEOL 1010 Lecture Notes - Lecture 2: Seafloor Spreading, Continental Crust, Bathymetry
29 Aug 2016
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Continental drift hypothesis: observed by wegener in 1915. He proposed that a supercontinent, pangaea, began breaking apart about 200 million years ago and that the continents that we know today drifted" into their current positions: evidence for this theory: 1) continents fit together like puzzle pieces. He observed that the seafloor had mountain ranges and deep trenches that were previously unknown. The seafloor spreading hypothesis provided an explanation for how the continents move: volcanic eruptions at mid-ocean ridges created new oceanic crust which would push continents apart, further evidence of seafloor spreading: seafloor composition and magnetic properties. The seafloor consists almost exclusively of the iron-rich igneous rock called basalt. Two types of crust: continental crust and oceanic crust. Seafloor magnetic stripes: these stripes are symmetric on either side of the mid-ocean ridges. Earth"s magnetic field is due to the flow of material in the liquid outer core.
