Chapter 5: Weathering and Soil Weathering is the process that changes the physical and chemical characteristics of rocks when exposed to the atmosphere and broken down into soil. It is the disintegration and decomposition of rock at or near the surface of the earth. What is unique about this process is that it affects the rocks in place and no transportation of the rocks is involved. This differentiates weathering from erosion. During this process, rocks undergo mechanical and chemical weathering. Mechanical weathering is the disintegration and the breakdown that allows rocks to break into smaller fragments. Mechanical weathering breaks up rocks but does not change its mineral content. Also in mechanical weathering, the rock particles are …show more content…
Rock particles created by mechanical weathering can be further altered and broken down by chemical weathering. Mechanical weathering takes place mostly in regions where there is considerable daily range of temperature. Mechanical weathering occurs mainly by temperature and pressure changes. The process of mechanical weathering involves pressure release, frost action, plant roots, and salt crystal growth. Pressure Release is when pressure is maintained on the formation of the overlying material that may be other rock formations, gravels, clays, or soils. When erosion or plate tectonic shifting removes enough of the overburden, most often by glacial action and then the melting of the glacier itself, the pressure is released. The formation expands and fractures parallel to the outer surface and large sheets of rock can fall away. This is what causes some large round boulders and also dome mountains. Frost action occurs in places with temperatures varying above and below …show more content…
This chemical reaction depends on the climate, minerals, and rocks they interact with. This process takes effect when the inner structure of a mineral is adjusted by the additional or elimination of elements. Change in phase and composition are due to the action of chemical products. Chemical weathering is dependent on unoccupied surface for reaction of temperature and presence of chemically active fluids. Smaller particle sizes means that they were weather by chemical weathering more rapidly than larger particles due to an increase of surface