Geology 1002 (Section 1) Honors Physical Geology Howe-Russell E131 TTh 9:00-10:30 Instructor: Jeffrey A. Nunn Office:Room E235 Howe-Russell Telephone:578-3353 e-mail: gljeff@lsu.edu Office hours: 4:00 to 5:00 MT or by appointment Resources Class web page http://www.geol.lsu.edu/jnunn/1002.1/ Course outline, exam schedule Outlines of each lecture Chapter Summaries/Review Sheets Post grades Text: Understanding Earth (Fifth Edition) (2006), Grotzinger, Jordan, Press, and Seiver Publisher web page: http://www.whfreeman.com/understandingearth/ Photos, Animations Study Guides Links Quizzes Classroom Conduct Turn off cell phones and other electronic devices Put away newspapers, magazines etc. Arrive on time If you MUST leave early, let me know and leave quietly 1
Evaluation Three in Class Exams (100 points each) questions may be T/F, multiple choice or short answer make up exams are essay graded on a curve Final Exam (150 points) - Comprehensive Seven Projects (40 points each) Nine Quizzes (Top 7 worth 10 points each) Field Trip to Tunica Hills Saturday Nov. 15 Optional Extra Credit Fun!!! No LSU Football Geologic processes range over many spatial scales 2
Some geologic processes are slow, but measurable and important over millions of years Rocks and Minerals Diamond versus Graphite Earth s Interior Earthquake in Northridge, CA in 1994 3
Surface Processes Mineral and Energy Resources are vital to Civilization Man s activities are having an impact on the Earth Indiana Coal Strip Mine 4
Hypothesis -Theory - Law A hypothesis is an explanation initially offered for a set of observations. When a hypothesis withstands many tests it may be called a theory. A theory for which it seems there to be no sensible reasons to challenge is called a law. The Scientific Method Simply put: Always ask yourself, How will I know if I m wrong? Fig. 1.1 A Good Theory is... Parsimonious (is the simplest explanation available) Consilient (explains a wide range of phenomena) 5
Mt. Everest Typical elevation of land surface is 0 1 km Depth (km) Elevation (km) Marianas Islands Sea level Himalayan Mountains Challenger Deep Marianas Trench Typical depth of ocean is 4 5 km The most recent layer is about 250 million years old. The explosive impact of a meteorite created this 1.2-km-wide crater in just a few seconds. The rocks at the bottom of the Grand Canyon are 1.7 2.0 billion years old. Crust Mantle Liquid iron outer core Solid iron inner core 6
Less dense continental crust floats on denser mantle. Continental crust is less dense than oceanic crust. 0 (km) 10 20 Oceanic crust (3.0 g/cm 3 ) Continental crust (2.8 g/cm 3 ) 30 Mantle 40 (3.4 g/cm 3 ) 50 Horizontal distance not to scale Moho discontinuity Density of Earth s Major Layers Aluminum (8%) Iron (6%) Silicon (28%) Magnesium (4%) Calcium (2.4%) Crust CRUST Oxygen Other (5.6%) (46%) Density (g/cm 3 ) Aluminum (2.4%) Iron (6.3%) Silicon (21%) Magnesium (22.8%) Mantle Calcium (2.5%) MANTLE Oxygen Outer core (44%) Inner core Depth (km) OUTER CORE INNER CORE Iron (85%) Iron (94%) Nickel (5%) Sulfur (5%) Oxygen (5%) Nickel (6%) Depth (km) Earth is an open system The Sun drives Earth s external engine. Solar energy is responsible for our climate and weather. Earth s internal engine is powered by trapped heat and radioactivity in its interior. Sun Heat radiating from Earth balances solar input and heat from interior. Meteors move mass from the cosmos to Earth. 7
The Earth system Cryosphere THE CLIMATE SYSTEM Atmosphere Hydrosphere Biosphere Lithosphere THE PLATE TECTONIC SYSTEM Inner core Asthenosphere Outer core Deep mantle THE GEODYNAMO SYSTEM Convection causes hot water to rise...where it cools, moves laterally, sinks, Hot matter from the mantle rises, causing plates to form and diverge. Plate Plate Where plates converge, a cooled plate is dragged under warms, and rises again. sinks, warms, and rises again. 4560 Ma Earth and planets form 4510 Ma Moon forms 4470 Ma Oldest lunar rocks 4000 Ma Oldest continental rocks 3800 Ma Evidence of erosion by water 4000 2700 Ma Start of rise of atmospheric oxygen 3500 Ma Record of magnetic field Fossils of primitive bacteria 3000 2500 Ma Major phase of continent formation completed 2000 1500 542 Ma Evolutionary Big Bang 500 1000 Mass extinctions 359 Ma 251 Ma 200 Ma 65 Ma Present 443 Ma Mass extinction 420 Ma Earliest land animals 125 Ma Earliest flowering plants 5 Ma First hominids 0.2 Ma First appearance of our species, Homo sapiens 8