GGR100H1 Final: GGR100 Study Notes.docx
Document Summary
Week 7: the dynamic planet; tectonics, earthquakes and volcanoes. Principle of superposition: younger layers are at the top, older layers are at the bottom. Uniformitarianism: physical processes that occurred throughout time are still occurring today. Seismic tomography allows us to study earth"s layers; seismic waves flow quicker through hard crust than hotter interior. The inner core is comprised of solid iron, which is hotter than the melting temperature of surface iron. The outer core has a lighter density; liquid molten magnetic iron, generates 90% of the earth"s magnetic energy, and circulation converts thermal/gravitational energy into magnetic energy. About 80% of earth"s volume, rich in oxides of iron, magnesium and silicates. Increased depth = increase in density, temperature and stiffness (due to pressure). From deepest to shallowest: upper mantle, asthenosphere, uppermost mantle, continental crust. About 10% of the asthenosphere is molten, which causes plate tectonics. Endogenic (internal, constructionalist) processes: tectonics, internal movement of heat/materials; builds landforms.
