Chapter 3 Landforms 2014 Pearson Education Inc Geomorphology Study of landforms and processes that create them Lithosphere Rocks and soil Surface landforms Plains Mountains and hills Valleys 2014 Pearson Education Inc Landform Processes Endogenic internal forces beneath or at Earth s surface Mountain building Earthquakes Volcanoes Exogenic external forces Chemical Erosion water wind Transport 2014 Pearson Education Inc Plate Tectonics Pangaea hypothesis Supercontinent Plate tectonics theory accepted from 1960s 2014 Pearson Education Inc Past Plate Movements 2014 Pearson Education Inc Earth s Moving Crust Earth s crust is thin and rigid Mantle beneath the crust very thick fluid Tectonic plates Pieces of Earth s rigid crust Plate movement Earthquakes Volcanoes Mountain building 2014 Pearson Education Inc Earthquakes Sudden movements of the Earth s crust Happen daily most too small to feel 2014 Pearson Education Inc Locations of Earthquakes 2014 Pearson Education Inc Earthquakes Epicenter surface directly above focus Seismograph recording device for seismic waves 2014 Pearson Education Inc Earthquake Focus and Epicenter 2014 Pearson Education Inc Volcanoes Magma molten rock Lava molten rock reaching Earth s surface Volcano surface vent for lava Magma may flow over the surface forming a plain of volcanic rock or it may build up to form a mountain 2014 Pearson Education Inc Slopes and Streams Exogenic processes originate in atmosphere affect lithosphere reshape the Earth s crust into new landforms in two steps Weathering Rocks are broken down into smaller pieces Transport Rock pieces are transported by gravity water wind or ice 2014 Pearson Education Inc Weathering Process of breaking rock into pieces First step in formation of soil 2014 Pearson Education Inc Two Types of Weathering Chemical weathering process of breaking down rock by interacting with elements Exposure to air and water Acids released by decaying vegetation Leaching Oxidation Decomposition of calcium carbonate Mechanical weathering process of breaking down rocks by physical forces expansion and contraction 2014 Pearson Education Inc Examples of Weathering 2014 Pearson Education Inc Moving Weathered Material Once rocks are weathered they are transported Mass movements movement of material under the pull of gravity Surface erosion occurs when material is moved by water or wind 2014 Pearson Education Inc Mass Movement of Weathered Material Slow gradual movement near the surface soil creep Dramatic movements such as rock slides landslides and mudflows 2014 Pearson Education Inc Surface Erosion Due to Rainfall The most common form of surface erosion is caused by rainfall Water that does not infiltrate runs off the surface Picks up particles as it travels 2014 Pearson Education Inc Rills and Sediment Transport 2014 Pearson Education Inc Floodplain Nearly level surface at the valley bottom through which a river flows 2014 Pearson Education Inc Floodplain Shaped by meanders changes in direction Erosion from side where current is swifter Deposition on side where current is slower 2014 Pearson Education Inc Features of a Meandering Channel 2014 Pearson Education Inc Meandering Channel Oxbow Lakes 2014 Pearson Education Inc Human Activity and Erosion Sharply increases amount of sediment in streams Major contributors Deforestation Agricultural development Urban development 2014 Pearson Education Inc Ice Wind and Waves In some parts of the world running water is a less powerful erosional agent Other erosional agents Ice Wind Waves 2014 Pearson Education Inc Glacial Retreat 2014 Pearson Education Inc Impact of Past Continental Glaciations Soils thin with bedrock readily visible Transported large amounts of material to new locations 2014 Pearson Education Inc Extent of Continental Glaciation in Last Ice Age 2014 Pearson Education Inc Wind Erosion Significant shaper of landforms in Deserts Farmland Coastal zones Carries great quantity of fine grained sediment Sand Silt Loess deposits of windblown material 2014 Pearson Education Inc Waves Winds blow across the water surface transferring energy and generating waves 2014 Pearson Education Inc Tsunami Waves Tsunami long wave caused by underwater earthquake At coast the speed slows Wave height increases Breaking wave releases erosive energy on beach 2014 Pearson Education Inc Tsunami Waves 2014 Pearson Education Inc Sea Level Change and Erosion Continuing to rise as seawater volume increases from glacial melting Causes increased erosion as waves break closer to shore 2014 Pearson Education Inc Human Impact on Coastal Erosion 2014 Pearson Education Inc Environmental Hazards Can be rapid Volcanic eruption hurricanes landslides Can be gradual Continual erosion deterioration of humanmade structures Human activity can destabilize landforms increasing risk to those living near them 2014 Pearson Education Inc Environmental Hazards 2014 Pearson Education Inc End of Chapter 3 2014 Pearson Education Inc