Class 2a: Landforms or What goes up must come downToday’s classRock cyclePlate tectonicsSlide 5Slide 6Slide 7Slide 8Slide 9EarthquakesSlide 11DiastrophismVolcanismSlide 14Slide 15Slide 16Slide 17Slide 18Gradational processesWeatheringSlide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Erosion and depositionSlide 30Slide 31Slide 32Slide 33GlaciersSlide 35Slide 36Slide 37Waves and coastlinesSlide 39Slide 40Slide 41Slide 42Class 2a: LandformsorWhat goes up must come downToday’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, OceaniaRock cycle•Your responsibility!•Differences between igneous, sedimentary, metamorphic•Examples of eachPlate tectonics•Theorized in 1912; proven after WWII•12 large plates (lithosphere) float on liquid rock (asthenosphere)•200 million years ago, all one continent (Pangaea)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 quakesEarthquakes•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) doBam, Iran 12/26/2003Diastrophism•Your responsibility!•Folding vs. faulting•Escarpment, rift valley, fault-block mountain (Sierra Nevada)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 dangerousMt. St. Helens 5/18/1980Mt. St. Helens 5/18/1980Mt. St. Helens 5/18/1980Krakatoa, Indonesia 8/26/1883Krakatoa, Indonesia 8/26/1883Gradational processes•Weathering –Chemical vs. physical•Mass movement•Erosion/deposition–Water (rivers, oceans)–Ice (glaciers)–WindWeathering•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 changeFrost actionWeathering•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 soilOxidationCarbonationCarbonation: KarstCarbonation: SinkholesCarbonation: SinkholesErosion 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 fansFloodplainDeltaLeveeILMOAlluvial fanArroyo (TX)Wadi (Oman)Glaciers•Rivers of ice•Carve out landforms from mountains–Glacial troughs–Fjords–Cirques•And deposit material when they leave–Outwash plain–MorainesGlacial landformsTajikistanKyrgyzstanGlacial landforms: CaliforniaGlacial landforms: IowaWaves 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 landformLongshore currentPacific PalisadesErosion vs. depositionAcapulcoCancúnGreat Barrier ReefGreat Barrier
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