GEOL 100 Lecture Notes - Lecture 4: Asthenosphere, Seafloor Spreading, Mantle Plume
31 Jan 2017
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Rising mantle plumes: columns of hot rock going through the mantle & creating a hot spot. When the plate moves, the old volcano goes extinct and a new one forms, creating a chain of volcanoes: yellowstone is a mantle plume. Mauna loa largest volcano on earth. Plate velocities: 1-18 cm/year: similar to the rate at which fingernails grow. Convection theory not a valid argument anymore. Slab pull sinking oceanic plate: old oceanic lithosphere becomes too dense and sinks (pull is not a good name since it is actually sinking) Slab suction: oceanic lithosphere sinks, sets up circulation pattern, exerts suction force. Ridge push: high elevation at midocean ridges, gravitational sliding of plate off of elevated edge, hot asthenosphere rises to fill gaps. Plates moving away from each other: convergent. Plates moving opposite directions while next to each other.
