1. November 14, 2011

2.  I will return your exams tomorrow. (Grades Look Good)  Pick up a textbook from the library  We will start Unit 3 today( Tectonic Processes)  This unit has a lot of vocabulary words. Please download the vocabulary pdf from my website.

3.  Let's look at Tectonic Processes. These are the forces that are trying to build the earth. Physical evidence of this happening includes volcanoes, earthquakes, folds, and faults.

4.  Knowledge has come from studying seismic waves which are generated by earthquakes and are registered on seismographs

5.  1) Body Waves: travel through the interior of the earth  a) primary (P) or compression waves: travel fastest through any material  b) secondary (S) or shearing-deformation waves: travel only through solid materials

6.  Surface Waves: travel only through the crust (i.e. L or long waves)

8.  Crust or Lithosphere  5 to 64 km thick  brittle shell of solid rock that cracks, warps, and bends  thinnest on the ocean floors  Sial (i.e. light granitic rock): major component of the continents  Sima (i.e. dense basaltic rock): major component of the ocean basins

9.  approx. 2900 km thick  upper part is known as the asthenosphere very hot, approx. 1650 deg. C in upper part  driving force for volcanoes, mountain building, and continental drift

10.  approx. 2900 km thick  Outer core: likely made of liquid iron  Inner core: believed to be solid iron, 4000 to 6000 deg. C, inner heat believed to be caused by the decay of radioactive rock

11.  located in the upper mantle - partially molten (i.e. approx. 10%) - lithosphere "floats" on top of the asthenosphere - zones that have become molten, or partially molten, can develop convection currents - convection currents in the asthenosphere are responsible for plate movement

12.  Convection currents in the outer core are partially responsible for the earth's magnetic field but do not drive the tectonic plates  convection: transmission of heat within a liquid or gas by movement of heated particles.  molten: liquefied by heat