GEOL107 Lecture Notes - Lecture 7: Alfisol, Ultisol, Mollisol
18 Sep 2018
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Document Summary
Weathering - physical disintegration (breaking up into smaller pieces) and/or chemical decay (change by chemical reactions) of rocks and minerals at/near the surface of earth. Importance of all forms of mechanical weathering is they cause rock to break into smaller pieces. Mechanical weathering causes rock to break into smaller pieces. Smaller pieces of rock, greater amount of surface area of rock exposed to chemical weathering. One of the unique properties of water is that it expands (rather than contracts) when it freezes - volume increases by about 9% When rock has cracks with water and when water freezes, expansion due to ice exerts pressure on rock over long periods of time of repeated freeze/thaw. Organic activity - effect of plants and animals. Will react with exposed surface area of rocks and minerals to cause chemical weathering. Carbon dioxide and water react in atmosphere to form carbonic acid and this reacts with calcite, causing calcite to dissolve (solid to liquid)
