GEOL 106 Lecture : Geology 106 lecture note
19 Jan 2012
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Earth"s internal heat y complete cycle of mantle = 500 million years y p wave (compression wave) can travel mantle + into outer/inner core y s wave (shear wave) only into mantle. Tectonics: large-scale geologic processes that deform earth"s lithosphere, producing landforms such as ocean basins/ continents/ mountains. Lithosphere is broken into large pieces called lithospheric plates that move relative one another. Plate tectonics: processes associated with the creation/ movement/ destruction of these plates. Patterns of magnetic polarity on the atlantic ocean floor near iceland were found to match on either side of the mid-ocean ridge. Symmetrical magnetic patterns could be explained by the idea of sea-floor spreading (fig 2. 13) Causes movement of pre-existing rocks (older rocks further away) Basic mechanism of plate tectonics (movement of tectonics) Age of ocean floors can be determined by magnetic patterns: youngest near ridges, older away from ridges. Maximum oceanic crust: age of 200 mil yrs (fig 2. 15)
