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Download Constructive and Destructive Forces
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Constructive and Destructive Forces Processes That Act Upon Earth’s Surface Features What are Constructive and Destructive Forces? • Constructive Force – A constructive force is a process that raises or builds up the surface features of the Earth. • Destructive Force – A destructive force is a process that lowers or tears down the surface features of the Earth. What Are Surface Features? – Surface features are landforms and bodies of water that cover the Earth’s surface such as: • • • • • • • • • • • • • mountains valleys canyons gorges beaches sand dunes barrier Islands flood-plains moraines and drumlins volcanoes oceans lakes rivers How Can a Surface Feature be Changed by a Constructive Force? – Natural forces such as wind, water, ice, through the process of deposition. • Deposition is the process of dumping sediment, dirt, rocks, or particles in one place. – The movement of the Earth’s crust through Plate Tectonics Constructive Force Examples of Deposition Constructive Process Deposition Surface Feature Deltas Floodplains Beaches and Barrier Islands Sand dunes Moraines and drumlins Force/Agent water / river water / river water / ocean long-shore current wind Ice / glacier Other Constructive Forces Constructive Surface Process Feature Folding Mountains Faulting Mountains Earthquake Trench Fault Mountains Islands Volcanic Activity Force Plate tectonics Plate tectonics Plate tectonics Plate tectonics How Can a Surface Feature be Changed by a Destructive Force? – Physical or Chemical Weathering • Weathering is the breaking down of rock into sediment. – Natural forces such as wind, water, ice, through the process of erosion. • Erosion is the movement of sediment from one place to another. Changing the Earth’s Surface by a Destructive Force Examples of Weathering • Mechanical / Physical Weathering – Temperature ChangeFreezing and thawing of Rock – Ice Wedging-Water freezing and expanding in cracks of rock – Impact of organisms • Root Pry • Animals burrowing • Chemical Weathering – Oxidation / rusting – Carbonic Acid / acid rain • Caverns – Impact of organisms • Secretion of acid from Lichen Destructive Force Examples of Erosion Destructive Process Erosion Surface Feature Canyons, Gorges, VShaped Valleys Sea Arches, Sea Stacks Buttes, Desert Force/Agent Water Water Wind U-Shaped Valleys Ice Mudslide, Gravity Sinkholes Other Destructive Forces • Volcanic Activity – Movement of Earths Crust (Plate tectonics) • Reshaping of Mountains • Earthquakes – Movement of Earths Crust (Plate tectonics) • Trenches – cracks in the Earth Curst What Do You Think? Deposition is a process that… A. B. C. D. Dissolves sediment Breaks down rock to form sediment Removes sediment from landforms Drops sediment to form landforms Where do deltas form? A. B. C. D. In desert areas At river mouths On the banks of rivers In valleys formed by glaciers Long shore currents help create… A. B. C. D. Beaches Dunes Rivers Drumlins Volcanoes can create new land when they release… A. B. C. D. Lava Water Faults Mud What forms moraines and drumlins? A. B. C. D. Wind Rivers Glaciers Volcanoes What landform forms from deposition at the mouths of rivers? A. B. C. D. a delta a floodplain a sand dune a moraine What is weathering? A. A type of climate B. The transport of sediment C. The breakdown of rock D. The aging of rock Which of these is caused by chemical weathering? A. B. C. D. desert pavement formation of U-shaped valleys formation of rust ice expanding in cracks in rock at is weathering? How do earthquakes change the land? A. B. C. D. They transport sediment. They form cracks in the surface. They release ash and lava. They cause chemical weathering. A river can form … A. B. C. D. Sea arches. U-shaped valleys. V-shaped valleys. Desert pavement. Deposition forms these features on coasts. A. B. C. D. drumlins floodplains barrier islands U-shaped valleys What causes V-shaped valleys to form? A. B. C. D. deposition at river mouths erosion by rivers weathering by wind erosion by glaciers What does erosion do? A. B. C. D. breaks down rock physically moves broken pieces of rock changes rock chemically change sediment into rock
