Earth SC-202 Physical Geology Instructor • • • • • • Prof. Steven Dutch Office: LS 402 Phone: 465-2246 Email: [email protected] Home Page: www.uwgb.edu/dutchs Office Hours MWF 10:30-11:30, TR 9:30-10:50 What is Physical Geology? Erosion Soils Weathering Fossils Wind Water Oceans Glaciers Underground Surface Sedimentary Earth History Rocks Volcanoes Metamorphic Earth’s Interior Igneous Plate Tectonics Earthquakes Mountains Mineral Resources Other Planets Intrusions Syllabus • Introduction to the course • Minerals • Igneous Rocks and Volcanoes • Weathering and Erosion • Evolution of Landscapes • Sedimentary Rocks • Evolution, Fossils, Geologic Time • Glaciers • Wind and Wave Erosion • Metamorphism and Deformation • Earthquakes and Earth's Interior • Continental Drift and Plate Tectonics • Resources from the Earth • Geology of other Worlds Exams and Grading Midterm I Midterm II Lab Final Field Trip Attendance 50 points 50 points 100 points 80 points 20 points 10 points Total 300 points A AB B BC C CD D 270+ 255-269 240-254 225-239 210-224 205-210 200-204 Field Trip • • • • • • • Dates Mandatory – Absence Excuse Required 8:00 LS Parking Lot, Return 4:15 Casual Clothing – No strenuous hiking Bring a lunch and fluids Rest stops provided Put on your calendar! No excuses! Lab • Instructor: Jennifer Wessel • Enroll in one section • 100 points total Expectations • Commitment – Focus in class • Professional Conduct – No talking, texting – Stay whole period – Stay vertical and awake • Use Syllabus • Know your ID number or bring ID to exams Sample exam question • Which is the most desirable property in a gemstone? a. b. c. d. High hardness Low hardness Excellent cleavage Density Signs of Trouble • Not making connections – Lecture, lab, text, on-line, exams • Not knowing your grade • Not knowing what to study for • Not knowing what’s on syllabus Geology and Other Sciences Physics Chemistry Biology •Geophysics •Mineralogy •Paleontology •Seismology •Petrology •Paleo????ology •Geochemistry Astronomy Geology •Historical Geology •Planetary Geology •Economic Geology •Geomorphology •Helioseismology •Hydrology •Oceanography •Engineering Geology •Structural Geology •Volcanology Who Geoscientists Are: • About 30,000 in the U.S. • Globally, in rich and poor countries, about one per $50 million GNP. • Mostly male but changing rapidly (now about 25% female in U.S.) • Still less than 10% minority in U.S. (moving up slowly) Where Geologists Work • 40 % Private Sector • 30 % Academic • 30 % Government What Geologists Do: • Locate Geologic Resources • Geologic Hazard Mitigation – Geological and Mining Engineering – Site Study – Land-Use Planning • Environmental Protection – Environmental Impact – Ground Water and Waste Management • Basic Research (Furnishes fundamental knowledge for the applications) Some Unique Aspects of Geology Importance of Relationships • Sequential • Spatial Importance of Time Distinctive Problems of Evidence • Slow Rates • Rare Events • Destruction of Evidence • Inaccessibility Some Geologic Rates Cutting of Grand Canyon • 2 km/3 m.y. = 1 cm/15 yr Uplift of Alps • 5 km/10 m.y. = 1 cm/20 yr. Opening of Atlantic • 5000 km/180 m.y. = 2.8 cm/yr. Uplift of White Mtns. (N.H.) Granites • 8 km/150 m.y. = 1 cm/190 yr. Some Geologic Rates Movement of San Andreas Fault • 5 cm/yr = 7 m/140 yr. Growth of Mt. St. Helens • 3 km/30,000 yr = 10 cm/yr. Deposition of Niagara Dolomite • 100 m/ 1 m.y.? = 1 cm/100 yr. 1 Second = 1 Year • • • • • • • 35 minutes to birth of Christ 1 hour+ to pyramids 3 hours to retreat of glaciers from Wisconsin 12 days = 1 million years 2 years to extinction of dinosaurs 14 years to age of Niagara Escarpment 31 years = 1 billion years Some Unique Aspects of Geology (Continued) Reliance on Inference and Deduction Intrinsically "Unsolvable" Problems • Ancient Landscapes • Mass Extinctions • Ancient Ocean Basins Scientific Principles in Geology • Parsimony (K.I.S.S.) • Superposition • Uniformitarianism Using these, plus observation, we establish facts about Earth Processes Parsimony • The simplest explanation that fits all the data is preferred • Doesn’t guarantee that things must be simple! • Theories with lots of ad hoc or unsupported ideas are probably wrong. Parsimony: What is the best interpretation of this well data? Parsimony • This? • Or This? Parsimony • Rock layers throughout NE Wisconsin are nearly flat and little disturbed • Glacial deposits are always on top of bedrock • Therefore this is the most likely interpretation One Implication of Parsimony How do we know the laws of nature are the same everywhere? • Out to the farthest stars, everything seems to obey the same laws of nature • We find nothing in the rocks to suggest the laws of nature were different in the past Either: • The laws of nature change but just happen to produce effects that look like the presentlyknown laws of nature – or – • The laws of nature really are the same everywhere Another Implication of Parsimony • We live in a universe of patterns • If someone claims there is an exception to a known pattern, the simplest explanation is that he/she is wrong • Therefore the burden of proof in science is on the challenger Superposition Whodunit? • Last night, one of Green Bay’s premier beer can collections was stolen • The only clue is footprints in the snow • The thief was the last person to leave the premises The Suspects • • • • • The Nephew The Maid The Cook The Handyman The Butler Has a seeing-eye dog Drives a car Rides a motorcycle Rides a bike Walks to work The Crime Scene • The Nephew has a seeing-eye dog • The Maid Drives a car • The Cook Rides a motorcycle • The Handyman Rides a bike • The Butler Walks to work Contacts A Contact: Mindoro Cut, Wisconsin Uniformitarianism Continuity of Cause and Effect • Apply Cause and Effect to Future - Prediction • Apply Cause and Effect to Present Technology • Apply Cause and Effect to Past Uniformitarianism Uniformitarianism does not mean: • • • • Catastrophes never occur Physical Conditions on Earth never Change Earth has always been the same Physical processes always occur at the same rate or intensity • Laws of Physics have always been the same Uniformitarianism does mean: Using our knowledge of physical laws, we can test: • Whether catastrophes have occurred • Whether physical conditions on earth have changed, and if so, how (ice ages, warm periods, high or low sea level, etc.) • Whether physical laws themselves have changed in time, or elsewhere in the universe.