EARTH121 Lecture 1: EARTH 121 Midterm Notes
16 Sep 2018
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How do we determine the age: relative ages: based upon order of formation, numerical ages: actual number of years since the actual event. Plate tectonics: nicholas steno: relative age (qualitative method, james hutton(quantitative, sir william logan, j. tuzo wilson. Important in plate tectonics due to temperature and pressure: lithosphere: outermost layer; crust and upper mantle. What makes up the tectonic plates: asthenosphere: below the lithosphere, upper mantle below the lithosphere. Changes in past positions of continents and ocean basins. The origins of mountain belts and seamount chains. The origin and ages of ocean basins. Alfred wegner: pangea; land masses slowly move-> continental drift. Evidence of continental drift: fossils, mountain ranges, continent. Sea-floor bathymetry: eco sounding sonar allowed rapid sea floor mapping from ships crossing the oceans. The ocean floor: discoveries: mountain range runs through every ocean, deep ocean trenches occur near volcanic island chains, submarine volcanoes poke up from the ocean floor, huge fracture zones segment the mid-ocean ridge.
