GEOL 1340 Lecture Notes - Lecture 19: Basalt, Peridotite, Asthenosphere
14 Oct 2016
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Document Summary
Chemical separation est. basic division of earth"s interior and structure. Short lived radioactive isotypes had half-lives of few million years and decayed. Long-lived radioactive isotopes keep planet warm today: earth 4. 5 billion years ago. As magma ocean cooled: interior of solid earth. Seismic reflection data: investigating deep processes. Use computers to model earth"s interior based on seismic refraction data. Tectonic forces can cause rigid crust of earth to deform and break along front. Travel through solid rock average v of 5 km/s. Can travel through solid, liquid and gas. Push/pull particles in direction of their travel path. Push material at right angles to their path of travel. Do most of destruction during earthquake: crust. Less dense (more buoyant) than oceanic crust. Lithosphere: crust and rigid portion of the upper mantle. 100-250 km beneath older portions of continents. Weak zone of partially melted peridotite that slows down seismic waves. Lower asthenosphere includes 2 transition zones with increase in seismic wave v.
