EARTHSS 1 Lecture Notes - Lecture 3: Seafloor Spreading, Continental Crust, Oceanic Trench
24 Oct 2018
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Where are we getting earthwuackes and voclanoes - thats where there are plate boundaries. Based on new evidence hess propsed for seafloor spreading hypothesis in 1960. Rising magma erupts at midocean rdges - pushing up like ^ New crust moves away from ridges, gathering sediment - pushes apart, the continents are pushed apart- warmest crust in the middle. At trenches, sea floor dives back into mantles - this is how we destroy crust- one plate is being force down the mantle - takes place of millions of year. How do we know its true and happening- confirmation 1 - the magnetic stripes on the seafloor. Magnetic reversals - we can date how old the crust is - we proved this spreading bby the magnetic striped flooring. Regions where very deep earthquakes occur where crust subducts back into the mantle - earth quackes represent owhen one plante is being subducted.
