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Weathering, Erosion, Deposition. Mr. Ahearn Earth Science 2010. Weathering. The breakdown do the materials of Earth’s crust into smaller pieces. Physical Weathering. Process by which rocks are broken down into smaller pieces by external conditions. Types of Physical weathering
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Weathering, Erosion, Deposition Mr. Ahearn Earth Science 2010
Weathering • The breakdown do the materials of Earth’s crust into smaller pieces.
Physical Weathering • Process by which rocks are broken down into smaller pieces by external conditions. • Types of Physical weathering • Frost heaving and Frost wedging • Plant roots • Friction and impact • Burrowing of animals • Temperature changes
Frost Wedging Describe how ice causes weathering?
Chemical Weathering • The process that breaks down rock through chemical changes. • The agents of chemical weathering • Water • Oxygen • Carbon dioxide • Living organisms • Acid rain
Water • Water weathers rock by dissolving it What evidence of weathering do you see in this picture?
Oxygen • Iron combines with oxygen in the presence of water in a processes called oxidation • The product of oxidation is rust
Carbon Dioxide • CO2 dissolves in rain water and creates carbonic acid • Carbonic acid easily weathers limestone and marble
Living Organisms • Lichens that grow on rocks produce weak acids that chemically weather rock
Acid Rain • Compounds from burning coal, oil and gas react chemically with water forming acids. • Acid rain causes very rapid chemical weathering
Karst Topography • A type of landscape in rainy regions where there is limestone near the surface, characterized by caves, sinkholes, and disappearing streams. • Created by chemical weathering of limestone
Rates of Weathering will depend on: • Climatic Conditions: • Cold and/or dry climates favor physical weathering. • Warm and wet climates favor chemical weathering. • Frost action works best in areas where the temperature fluctuates wildly.
Erosion • The process by which water, ice, wind or gravity moves fragments of rock and soil.
What is Erosion? • Erosion, is gradually wearing down the surface of the earth. • Erosionis the process by which weathered rock and soil (sediment) are moved from one place to another. • Erosion carves the Earth's surface creating canyons, gorges, and even beaches.
Erosion How much erosion takes place is determined by the: • Sum • Slope • Speed • Surface
Water Erosion • Rivers, streams, and runoff
Water Erosion When rain falls to the Earth it can evaporate, sink into the ground, or flow over the land as Runoff. When it flows over land, erosion occurs. Runoff picks up pieces of rock and "runs" downhill cutting tiny grooves (called rills) into the land.
Ice Erosion • Glaciers
Glaciers Glaciers can pick up and carry sediment that ranges in size from sand grains to boulders bigger than houses. Moving like a conveyor belt and a bulldozer, a single glacier can move millions of tons of material!
Mass Movements • Landslides, mudslides, slump and creep Faster Slower landslide clip.mpeg
Deposition Rock particles that are picked up and transported during erosion will ultimately be deposited somewhere else Deposition is the process by which sediments (small particles of rock) are laid down in new locations. • Together, Erosion and Deposition build new landforms. • Deltas • Canyons • Meanders • Floodplains
Where rivers meet the ocean is called the mouth of the river. Soil and dirt carried by these rivers is deposited at the mouth, and new land is formed. The new, soil-rich land is known as a Delta Delta
Canyons Canyons are large valleys created by a river or stream.
Meander Meandering streams wander side to side as they constantly seek out the lowest elevation. This constant motion creates a series of S-shaped “loops”.
These are low-lying areas along the sides of a river channel that have regular times of heavy waterflow to cause the river to spill over and flood the land. Floodplains
