![]() ![]() The release of pressure on the rock, alternatively the freezing and thawing of The expansion and contraction of heat, the erosion of overlapping materials, The main sources of physical Weathering are ![]() Involves breaking up the rock into the forming minerals or particles withoutĭisturbing the forming minerals. Of the rock and therefore depends on the application of force. Physical decomposition causes mechanical disintegration Processes that act separately or more often together to cause fragmentation andĭecay of rock material. Weathering involves physical, chemical, and biological It is more likely to be found in warm climates, where mechanical weathering by freezing ice is less likely.) Source: For example plant roots can enlarge cracks in a rock as they grow and expand.Spheroidal Weathering (Spheroidal weathering is most common among coarse-grained igneous rocks, especially granite and similar rock types. Solution occurs because many minerals are soluble and are removed when they come into contact with water.īiological weathering is the breakdown of rock by plants, animals and micro-organisms.This creates carbonic acid which breaks down rock. Carbonation occurs when carbon dioxide from moisture in the air reacts with carbonate minerals found in rock.This reaction makes the rock more susceptible to decomposition. Hydrolysis occurs whenwater reacts with minerals in the rock causing the chemical composition of the rock to change and become more unstable.Hydration occurs when water is absorbed by minerals in the rock, creating crystals which exert pressure on the surrounding rock, eventually causing it to crumble.Iron oxide is reddish brown in colour and causes the decomposition of rock. Oxidation occurs when oxygen reacts with minerals such as calcium and magnesium to form iron oxide.This cycle leads to exfoliation where the top layers of rock peel away.Ĭhemical weathering is the breakdown of rocks because of the interaction of air, water or acid with the chemical composition of the rock. Then at night, when temperatures fall, the rock also cools and contracts. During the day temperatures rise and heat the rock. Thermal expansion or insolation usually occurs in arid regions.Crystallisation leads to a dramatic increase in volume which exerts pressure on the surrounding rock, and can eventually fracture the rock. Salt crystallisation occurs in semi-arid environments, where the evaporation of water from rock surfaces leads to the crystallisation of salts.This cycle will eventually put enough pressure on the rock to causes pieces to fall off. When water freezes it expands, by on average 9%, this puts pressure on the surrounding rock. Water gets into cracks in the rock and at night, when temperatures fall the water can freeze. Frost wedging or freeze-thaw weathering primarily occurs in temperate humid climates.Importantly physical weathering does not change the chemical composition of the rock. This type of weathering occurs when rocks are broken down by physical factors in the environment, such as wind, water, and temperature change. Physical weathering is also known as mechanical weathering. The rate that weathering occurs at will depend on the rock type, the climate and the relief. There are three types of weathering physical, chemical and biological. Weathering is the breakdown of rocks in situ.
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