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Weathering. DEFINITIONS. WEATHERING. Weathering= the breaking down of rock into smaller and smaller pieces. Is weathering constructive, destructive, or both? Why? -Weathering is destructive- it “tears down” rocks and landforms. 2 Types of Weathering. MECHANICAL WEATHERING. 1. ANIMALS
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WEATHERING • Weathering= the breaking down of rock into smaller and smaller pieces. Is weathering constructive, destructive, or both? Why? -Weathering is destructive- it “tears down” rocks and landforms.
MECHANICAL WEATHERING 1. ANIMALS Little animals also help weathering by burrowing and digging through the ground.
2. Ice Wedging – when water gets into cracks of a rock, freezes & thaws over & over again & splits the rock MECHANICAL WEATHERING
MECHANICAL WEATHERING 3. PLANT GROWTH • Roots of plants also push into the rocks and break them apart. They act like wedges and push the rocks apart.
MECHANICAL WEATHERING 4. RELEASE OF PRESSURE- as erosion moves sediment from the surface, pressure is reduced. The outside of the rock begins to flake off
5. Abrasion-sediments carried by wind, water, or ice wear away rock by hitting & scraping against other rock MECHANICAL WEATHERING NONLIVING CAUSES
Abrasion Wind • sandstone shapes eroded by coastal winds Sandblasting
WATER - rubs fragments against each other andwears away the surface of the rock by abrasion. The faster the water, the greater the erosion Abrasion
Ice- Glaciers Abrasion • The glacier gouges out chunks of rock and leaves scratches on the rock calledstriations
CHEMICAL WEATHERING the chemical breakdown of rock and minerals into new substances CHEMICAL WEATHERING
Water is considered to be the universal solvent. It dissolves many things – including rock Over time, water can break down even hard rock like granite CHEMICAL WEATHERING
2) Oxygen Oxidation(rust) is a chemical reaction in which an iron combines with oxygen. CHEMICAL WEATHERING
3) Carbon Dioxide (CO2) -CO2 mixing with water creates Carbonic Acid that slowly dissolves limestone. (Acid in groundwater) -Caves CHEMICAL WEATHERING
CHEMICAL WEATHERING 4) Living Organisms Acids from decaying plants or fungi such as lichens breaks down rocks
is rain or snow that contains more acids than normal due to air pollution. The acid “dissolves” and “eats away” the rock CHEMICAL WEATHERING 5. ACID PRECIPITATION
Interactive Weathering • How are materials from the earth broken down?