PHYC 2451 Chapter Notes - Chapter 9: Van Allen Radiation Belt, Plate Tectonics, Oceanic Crust
19 Dec 2015
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Document Summary
Earth"s energy sources: all activity in earth"s atmosphere, oceans, and surface is powered by three sources of energy: solar energy is the energy source for the atmosphere. Earth"s interior: studies of seismic waves (vibrations produced by earthquakes) show that earth has a small, solid inner core surrounded by a liquid outer core. The mantle is composed of iron-rich minerals: both temperature and pressure steadily increase with depth inside earth. Plate tectonics: earth"s crust and a small part of its upper mantle form a rigid layer called the lithosphere. The lithosphere is divided into huge plates that move about over the plastic layer called the asthenosphere in the upper mantle: plate tectonics, or movement of the plates, is driven by convection within the asthenosphere. Molten material wells up at oceanic rifts, producing seafloor spreading, and is returned to the asthenosphere in subduction zones. Earth"s magnetic field and magnetosphere: electric currents in the liquid outer core generate a magnetic field.
