GEO 210 Lecture Notes - Lecture 14: Francis Bacon, Seafloor Spreading, Oceanic Trench
13 Apr 2020
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Document Summary
Rigid earth to plate tectonics: unifying theory of earth development and change, consistent with all observations, explains both present processes and existing features. Plate tectonics theory: plate boundaries: main location for earth"s volcanic and earthquake activity. This is the main place where mountains are created: type of plate boundary determines activity, 3 types, diverging (spreading, converging (colliding, transform (sliding past each other) What is a plate: lithospheric plate: crust + upper mantle, asthenosphere: plastic mantle. Isolated columns of hot magma rising slowly within the asthenosphere: melts overlying crust, can be underneath continents or ocean plates. The geography of volcanism: volcanism primarily submarine, several thousand volcanoes are continental, over 50,000 in the pacific ocean alone. Volcanism: volcanism, distribution of active volcanoes, types of volcano cones, shield volcano, composite volcano, lava dome, cinder cone, volcanic hazards. Layers of lava flows, pyroclastics, and hardened mudflow deposits.
