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Landforms or What goes up must come down

Landforms or What goes up must come down. Today’s class. "The summit of Mt. Everest is marine limestone." Tectonic forces Earthquakes, volcanoes Diastrophism Gradational processes Weathering, mass wasting Erosion/deposition: water, waves, wind Examples from CA, SW Asia, Oceania.

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Landforms or What goes up must come down

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  1. LandformsorWhat goes up must come down

  2. Today’s class • "The summit of Mt. Everest is marine limestone." • Tectonic forces • Earthquakes, volcanoes • Diastrophism • Gradational processes • Weathering, mass wasting • Erosion/deposition: water, waves, wind • Examples from CA, SW Asia, Oceania

  3. Rock cycle • Your responsibility! • Differences between igneous, sedimentary, metamorphic • Examples of each

  4. Plate tectonics • Theorized in 1912; proven after WWII • 12 large plates (lithosphere) float on liquid rock (asthenosphere) • 200 million years ago, all one continent (Pangaea)

  5. Plate tectonics • Divergent boundaries • Generally mid-ocean • Underwater volcanoes, few quakes • Convergent boundaries • Usually near continental edges • Violent volcanoes near ocean, strong quakes • Transform boundaries • No volcanoes, mild to strong quakes

  6. Earthquakes • Stress relief via crust movement • 500,000 per year; 800 felt • Seismic waves of energy • P-waves or primary waves (Slinky) • S-waves or secondary waves (up and down) • Earthquakes don't kill people, buildings (and gas mains) do

  7. Bam, Iran 12/26/2003

  8. Diastrophism • Your responsibility! • Folding vs. faulting • Escarpment, rift valley, fault-block mountain (Sierra Nevada)

  9. Volcanism • Pressure on molten rock • Composite volcanoes • Violent and explosive • Along subduction zones • Relatively hard to predict • Shield volcanoes • More calm and constant • Along divergent boundaries or at hot spots • Relatively less dangerous

  10. Mt. St. Helens 5/18/1980

  11. Mt. St. Helens 5/18/1980

  12. Mt. St. Helens 5/18/1980

  13. Krakatoa, Indonesia 8/26/1883

  14. Krakatoa, Indonesia 8/26/1883

  15. Gradational processes • Weathering • Chemical vs. physical • Mass movement • Erosion/deposition • Water (rivers, oceans) • Ice (glaciers) • Wind

  16. Weathering • Most mountains are going down faster than they’re going up • Mechanical weathering breaks rocks into smaller pieces • Frost action • Salt crystals • Roots • Exfoliation • Rock chemistry does not change

  17. Frost action

  18. Weathering • Chemical weathering changes the chemistry of rocks • Oxidation (exposure to oxygen) • Hydrolysis (exposure to water) • Carbonation (exposure to carbon dioxide) • Warmth and water encourage chemical reactions • Weathering loosens rock particles, creates soil

  19. Oxidation

  20. Carbonation

  21. Carbonation: Karst

  22. Carbonation: Sinkholes

  23. Carbonation: Sinkholes

  24. Erosion and deposition • Erosion carries particles away • Deposition deposits them • Running water • Constant water, floods • Most important landform agent in deserts • Floodplains, levees, and deltas • Arroyos and alluvial fans

  25. Floodplain Levee Delta

  26. IL MO

  27. Alluvial fan

  28. Arroyo (TX) Wadi (Oman)

  29. Glaciers • Rivers of ice • Carve out landforms from mountains • Glacial troughs • Fjords • Cirques • And deposit material when they leave • Outwash plain • Moraines

  30. Glacial landforms Kyrgyzstan Tajikistan

  31. Glacial landforms: California

  32. Glacial landforms: Iowa

  33. Waves and coastlines • Waves transfer energy, don’t move water • Energy moves particles down the coast (longshore current) • Newer coastline=erosion • Older coastline=deposition • Barrier reef: only organically formed landform

  34. Longshore current Pacific Palisades

  35. Erosion vs. deposition Cancún Acapulco

  36. Great Barrier Reef

  37. Great Barrier Reef

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