Weathering

Weathering Weathering is the process by which rocks break down and change Mechanical Chemical

Mechanical Weathering Mechanical(Physical) Weathering is the process where rocks break into smaller pieces with no change in their composition Caused by: Cold temperatures Tectonic Processes Biological Activity

Mechanical Weathering Frost Wedging-The repeated thawing and freezing of water in the cracks of rocks Water expands when frozen, chips away parts of the rock

Frost Wedging Expansion of freezing water in cracks and crevices Eventually breaking rocks into pieces Sections of rock that are wedged loose are called talus

Unloading Unloading occurs when igneous rock becomes exposed through uplift and erosion Exfoliation-Occurs when pieces of the uplifted rock are weathered and chipped away

Unloading The uplift and erosion of rocks overlying igneous rocks because pressure on igneous rocks is reduce Exfoliation—slabs of outer rock separate and break loose

Biological Activity Organisms can cause Mechanical Weathering Plant roots growing into cracks in rocks Burrowing animals moving rocks Decayed animals can produce acids (Chemical Weathering)

Chemical Weathering Chemical Weathering- Rocks undergo changes in their composition Caused by: Water Oxygen Carbon Dioxide Acids

Hydrolysis/Oxidation Hydrolysis-The reaction of water with other substances Oxidation-The reaction of oxygen with other substances

Water Water causes Chemical Weathering by absorbing gases from the atmosphere and ground CO2 +Water  Carbonic Acid Dissolves Rocks/Minerals Stalactites/Stalagmites

Statue of liberty The statue of liberty is made of copper which is generally a brownish color Has been affected by chemical weathering Water reacting with the copper Sulfuric acid formed by pollution (debatable)

Differential Weathering Differential weathering is when rocks weather at different rates Caused by different mineral compositions Sedimentary rocks weather more easily than igneous rocks