1	Physical Geology What is Geology?
2	What is Geology? The study of the earth, including Materials that make up the Earth Changes in the surface and interior of the earth Forces that cause the changes History of the planet History of life on Earth
3	A ‘Few’ Sub disciplines of Geology Mineralogy Petrology Geomorphology Structural Geology Stratigraphy Economic & Petroleum Geology Paleontology Paleoclimatology Seismology Geophysics Hydrogeology Geochemistry Environmental Geology Geotechnical Engineering Glaciology Planetary Geology Geothermal Energy Volcanology
4	Why is geology important? Energy related resources Oil and natural gas Geothermal Coal Hydropower Nuclear power Solar power Wind
5	Why is geology important? Protecting the environment Mining Non-renewable resources Predicting geologic hazards
6	History of Geology Uniformitarianism (late 1700’s) Physical processes operating in the present that modify the earth’s surface also operated in the past Proposed by James Hutton in his book Theory of the Earth Advanced by Charles Lyell
7	The Big Picture: Earth’s Internal Layers
8	Formation of Earth 4.6 billion years old Big Bang Theory Nebular hypothesis Our solar system formed from a cloud composed of hydrogen and helium, some heavy elements
9	The Layered Earth Earth’s layers developed over time Gravity and heat the main energy source Internal External Heat and Gravity are the driving forces of ALL Geologic processes! Earth layers can be described in two ways: Composition-what is it made of? Rheology-how strong is it?
10	Compositional Layers of the Earth Three main compositional layers Core Mantle Crust OCEANIC CONTINENTAL
11	Rheological Layers of the Earth Lithosphere Outermost rigid layer – cool crust and uppermost mantle Broken up into plates (i.e. plate tectonics) On average - 100 km thick
12	Rheological Layers of the Earth Asthenosphere Upper mantle Soft, weak layer beneath lithosphere Goes to depth of about 660 km
13	Rheological Layers of the Earth Mesosphere Lower mantle Depths of 660 km to 2,900 km More rigid than asthenosphere Core Outer core Molten metallic layer (2270 km thick) Behaves like a liquid Generates Earth’s magnetic field Inner core Fe rich sphere (r=1216 km) Behaves like a solid
14	Rheological Layers of the Earth Diagram courtesy of Eric Hiatt, University of WI, Oshcosh