Earth Sciences 2240F/G Lecture 3: Earth science 3
20 Jan 2018
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Document Summary
Accretion: the growth of a body as smaller objects stick to it, how the growth of a body became the planet earth, was once cold now hotter than the sun, following 3 sections is how the heat originated. Theia: mars-sized planet that side-swiped earth in the early days of the solar system, debris from it formed the moon. 2. 4 heat from radioactivity: virtually all of earth s current internal energy is derived from the energy of radioactivity. Short-lived radioactive isotopes: (now virtually gone, heat provided by radioactive decay processes was likely high b/c the abundance of short lived. Long-lived radioactive isotopes: have been producing heat energy all through earth s early history and will continue to do so for a long, long time yet. 3. 0 paleomagnetism and earth"s magnetic field: all skeptics of plate tectonics were convinced after the theory of paleomagnetism- study of earth"s magnetic field through the analysis of rock magnetism.
