2Weathering and Its Effects Surface processes that break down rock.Rock breaks down into sediment.Sediment breaks down into soil.2 TypesMechanical WeatheringChemical Weathering
3Mechanical Weathering Occurs when rocks are broken apart by physical processes.Mechanical weathering increases the exposed surface area of the rock.
4Mechanical Weathering Examples of mechanical weathering:PlantsBurrowing animalsIce WedgingWater enter cracks in rock.Water freezes and expands.Force of expansion breaks the rock apart.
5Chemical Weathering Chemical Weathering Occurs when chemical reactions dissolve or change the minerals in the rock.May weaken the rock.
6Chemical Weathering Examples of Chemical Weathering Natural Acids Water mixes with carbon dioxide in the air or soil to form carbonic acid.Carbonic acid reacts with calcite and dissolves limestone.Over time, caves are formed.
7Chemical Weathering Examples of Chemical Weathering: Natural Acids Over time acids can react with feldspar (found in granite and sandstone) to form the clay kaolinite.
8Chemical Weathering Examples of Chemical Weathering: Plant Acids Acids in roots or acids formed by decaying plants can dissolve the mineral in the rock.
9Chemical Weathering Examples of Chemical Weathering Oxidation Exposure of metallic minerals to air and water causes them to “rust”.Ex: Magnetite into limonite.
10Effects of Climate Mechanical weathering Chemical weathering Increases in areas with frequent freezing and thawing.Is most rapid in warm, humid areas.
11Effects of Weathering Effect of Rock Type: Marble weathers more rapidly than granite in humid climates.