Sam + Cades SOSE Presentation

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description

Weathering

Transcript of Sam + Cades SOSE Presentation

Page 1: Sam + Cades SOSE Presentation
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Physical/Mechanical: The breakdown of rocks and soils through direct contact with atmospheric

conditions, such as heat, water, ice, and pressure.

Chemical: chemical weathering, involves the direct effect of atmospheric chemicals or biologically produced chemicals (also known as biological weathering) in the breakdown of rocks, soils, and minerals.

Biological: Organisms (trees and vegetation) assistance in breaking down rocks/cliffs.

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Physical weathering, also known as Mechanical Weathering, can occur in many circumstances including:

-Frost Wedging – Frost wedging occurs when water gets stuck in a crack in a rock and is then frozen. When water is frozen it expands which causes pressure on the rock and can crack or break the rock.

-Thermal Expansion – Repeated daily heating of the rock causes expansion and then the cooling of the rock will sometimes cause it to crack

Physical weathering is the disintegration of earth material without undergoing a chemical change. Physical weathering results in increased surface area for chemical reactions to occur on.

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Chemical Weathering is the process by which rocks are decomposed, dissolved or loosened by chemical processes to form residual materials.

Chemical Weathering includes:

-Dissolution – Some common minerals that dissolve in water are Halcite and Calcite. Limestone and marble both contain Calcite and are soluble in acidic water. Caves and caverns form in limestone because of this and how easy it is to break down the rock.

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Form of weathering caused by the activities of living organisms – for example, the growth of roots or the burrowing of animals. Tree roots are probably the most significant agents of biological weathering as they are capable of prising apart rocks by growing into cracks and joints. Plants also give off organic acids that help to break down rocks chemically which is then led into chemical weathering

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