Discuss the view that geomorphological processes such as weathering, mass movement and those resulting from volcanic and earthquake activity cannot be managed but merely adapted to.
Discuss the view that geomorphological processes such as weathering, mass movement and those resulting from volcanic and earthquake activity cannot be managed but merely adapted to.
Weathering can be divided into three categories, mechanical, chemical and biological. Each of these involve the decomposition or disintegration of rocks at the Earth’s surface which occur without involving any movement or transport. Mechanical weathering breaks up the rock without any alteration to its existing mineral structure and is usually caused as a result of consistent temperature changes. The freeze-thaw process in the most common, this occurs when rocks containing cracks or fissures allow water to collect in them. The once temperatures drop below freezing, the water expands and places pressure on the rock sides. This is repeated numerous times until the rock breaks into pieces following any lines of weaknesses. While another type of mechanical weathering is “onion peeling”, which is typical in hot arid environments. The heat of the sun during the day causes the outer layers of rocks to expand and they are pulled away from cooler core and then they contract during the cooler night. This leads to the process of exfoliation in which the outer layers of rock are peeled away. Biological weathering operates only at local scale and is when the roots of plants and trees together with the work of burrowing animals help contribute to the disintegration of rock. Chemical weathering is the dominant type of weathering worldwide and is most associated with areas of a hot wet climate such as the tropics. In these areas heavy rainfall can cause the unstable minerals (mainly silica) to be leached from the soil while leaving the stable minerals of aluminum and iron in high concentrations in the soil. These form hard, almost rock like layers deep in the tropical soils up to ten metres thick and cause drainage problems and restricted plant root growth. Although chemical weathering is not only restricted to the tropics and can occur in areas of lower temperatures but not at the same rates as in the tropics. The process of carbonation can create distinctive landscapes and landforms in areas of limestone and these areas usually have poor surface drainage, disappearing surface streams, dry valleys and underground cave systems.