1. Class 2a: Landforms or What 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)

7. Plate tectonics Divergent boundaries Convergent 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

10. 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

11. Bam, Iran 12/26/2003

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

13. Volcanism Pressure on molten rock Composite volcanoes Shield 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

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

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

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

17. Krakatoa, Indonesia 8/26/1883

18. Krakatoa, Indonesia 8/26/1883

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

20. 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

21. Frost action

23. 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

24. Oxidation

25. Carbonation

26. Carbonation: Karst

27. Carbonation: Sinkholes

28. Carbonation: Sinkholes

29. 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

30. Floodplain
Levee
Delta

31. IL MO

32. Alluvial fan

33. Arroyo (TX)
Wadi (Oman)

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

35. Glacial landforms
Kyrgyzstan
Tajikistan

36. Glacial landforms: California

37. Glacial landforms: Iowa

38. 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

39. Longshore current
Pacific Palisades

40. Erosion vs. deposition
Cancún
Acapulco

41. Great Barrier Reef

42. Great Barrier Reef