Weathering is the chemical alteration and physical disintegration of Earth materials by the action of air, water and organisms. In other words, it is the breakdown of the rocks and their disintegration and decomposition without their movement from their original position to another area. Weathering is only the disintegration of the rocks particles without their distant removal. Weathering does not include the movement of the disintegrated particles. Weathering can be of the following three types:
(1). Mechanical Weathering
(2). Chemical Weathering
(3). Biological Weathering
Mechanical Weathering involves the breaking up of rocks through the effect of certain stresses such as frost and temperature. In chemical weathering, air and water act as the agents of the decomposition of rocks. The process of hydration, oxidation, and carbonation are the main means of chemical weathering The biological weathering is caused by plants, bacteria, and human beings. Read: Different types of weathering
Erosion is the process in which the particles resulting from weathering and mass movement are carried away over long distances. During transportation, further breakdown of the rocks and particles takes place. Major agents of erosion are the running water in the form of rivers and streams, glaciers, wind, coastal waves, and chemical solutions. River-water results in the formation of valleys and several landscapes such as alluvial cones and deltas. Similarly, underground water plays a key role in the formation of several landforms. The glaciers are also major agents of erosion. The work of glaciers completely changes the drainage system of the area through which they move. The landscape formed by the glaciers include cirques, hornes, U-shaped valleys, V-shaped valleys, and comb-ridges.