Chapter 01


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intro chapter to the course

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Chapter 01

  1. 1. SC1150 need a science ENVIRONMENTAL GEOLOGY need to know other: told I had to; needed elective; important for career interesting sounds easy Where should we spend our money in MN? Ranked answers QUIZ 0 RESULTS This group: - Needs a science course (27%) - Finds geo interesting  (33%) - Feels the info is necessary (27%) - Does not expect EnvGeo to be easy  …
  2. 2. SC1150 ENVIRONMENTAL GEOLOGY QUIZ 0 RESULTS: most people already know some geology T F water = over half Earth’s surface 93% 7% water = over half the Earth’s volume 75% 25% rocks are made of minerals 100% there’s more oil than coal 25% 75% drought is a MN concern 81% 19% glaciers were important in MN landscape 88% 13% Just one sticking point ! Jeff Bartlett
  3. 3. Your news items: ripped from the headlines
  4. 4. The Basic Idea This course includes the examination of Earth processes that influence human activities. Topics include Earth development, rocks and minerals, internal Earth processes, surface Earth processes, Earth resources, pollution, and waste disposal. Environmental Geology
  5. 5. Connects the lithosphere to the hydrosphere, atmos phere, biosphere & human sphere Environmental Geology
  6. 6. Hypothesis is formed to explain observations or data Makes predictions to test repeatedly and systematically Conclusion includes direction for further questions - actually continues a cycle But really – is this how our investigations work? Chaos – accidents and dead ends are very very common Mysteries drive curiosity Practical issues drive projects Economics is important for stakeholders Environmental Geology
  7. 7. Examples of traditional experimental science Actual hypothesis – experiment – result type process Environmental Geology
  8. 8. Geology has unique issues A pressing environmental issue: Tuvalu and sea level change Geology is an environmental science Rocks record how earth has changed Control of erosion and sedimentation Extraction of resources Recognition and mitigation of hazards Issues with scale A river is not easily fit within a laboratory Plate tectonics involves the whole Earth Problems with time Geologic processes take millions of years Geologists are limited by human time Problems with resolution of data New technology and procedures We can see more details now Environmental Geology “Sinking feeling in Tuvalu” BBC, 2002 “Tuvalu is growing” USGS, 2010
  9. 9. What it really takes : Observation– either natural or controlled circumstances Reasoning drive curiosity Evidence to collect and assess  important step! Progress includes both conclusions and new questions Environmental Geology
  10. 10. Formation of the solar system Formation of the earth Composition of the earth Interaction with humanity Geologic hazards Population Environmental Geology looks at interactions between humans and geologic environments Environmental Geology
  11. 11. The Big Bang Theory is the dominant scientific theory about the origin of the universe. widely accepted, but hard to prove The universe was created 10 - 20 billion years ago from a cosmic explosion that hurled matter and in all directions. [latest estimate = 13.8ish] Very smallest particles were forced into larger particles, then basic atoms of lightest elements: 1H, 2He, 3Li, and so on up to 16O Environmental Geology
  12. 12. Bigger elements had to be fused in stars themselves … that gets up to iron , 56Fe What about very heavy elements like gold, 197Au? Elements have to form during solar collapse, and resulting supernova explosions The only known process with energy that can form these elements… Environmental Geology
  13. 13. Planet #3: g/cc 1.4 • >4 billion years old • 15 o C, not really too hot or cold • Tilted >20º • Rocky with gases Environmental Geology 5.6  Formed ~5 billion years ago, out of swirling mass of gas and dust - the „solar nebula‟ Planet compositions depended on distance from the hot sun near = rocky / metallic   far = gaseous Nearest planets: metallic iron, few very high temp minerals, little water or gas. Farther from the sun: lots of low temp minerals, water, & condensed gases.
  14. 14. Early Earth – a barren world with a cratered surface Earth was target of many impacts Asteroids Comets Meteors Dust Particles One impact made our moon As cooling progressed, dense materials [Fe] sank lighter, low-density minerals [Si] floated out toward the surface = Environmental Geology =
  15. 15. Differentiation  Core: dense, hot Ni + Fe Mantle: thick zone that surrounds the core Mushy, hot ultramafic rocks Crust: Zone of interaction Oceanic (mafic)continental (felsic) Heat from core escapes by convection, keeping the planet constantly changing Environmental Geology
  16. 16. Heating and differentiation of the early earth formed crust, atmosphere and oceans. Minerals released gases Impacts brought extraterrestrial elements! Crust has loads of Si, O, and Al Atmosphere lacked free oxygen (O2) Dominated by N, CO2 & SO2 A Environmental Geology
  17. 17. Very early in the world, life began and interacted with the earth Earliest fossils show that bacteria used ancient atmosphere and „polluted‟ the seas with O2 Iron rained out of seas Result – oxygen in the atmosphere, and iron in the rocks! This is a great example of a feedback between biosphere, lithosphere and atmosphere Ecological interactions were responsible for changing the world: We would not exist if they hadn‟t Environmental Geology
  18. 18. A dangerous place! Fig 1.6-1.9 Partly because of us: - Choosing to live near hazards - Poor understanding - Contributing to risk Environmental Geology
  19. 19. Exponential growth: • Possibly 9 billion people by 2050 • Life span & birthrate up, mortality down • Mass mobility Inflection [change] point: • Acceleration is slowing to zero • Population decline in many countries Environmental Geology
  20. 20. Density is highly variable and depends on resources, space, culture, economics etc Figure 1.15 Figure 1.18 Environmental Geology
  21. 21. The Earth has some time left before the sun gets too hot. Based on their models, the scientists calculate that the planet will fall out of the habitable zone some time in the next 1.75bn to 3.25bn years. Then, the habitable zone will start beyond Earth's orbit, and make Mars more earth-like Environmental Geology