Distinction between weathering and mass movement (wasting)

Distinction between weathering and mass movement (wasting)

Weathering and mass movement (wasting) are two different processes that affect the surface rocks of the landscape. A clear distinction between the processes that lead to each of the two terms is very necessary. This helps to wipe off any confusion that may arise when discussing them.

Weathering refers to the mechanical (physical) disintegration and the chemical decomposition of the rocks without removing the broken pieces from their positions. It is only after a certain amount of fragmentation has taken place that the removal of the particles commences by the agents of erosion. This marks the first step in shaping of the earth’s surface by external processes. It is the exposed rocks that are mostly affected by these processes.

The weathering agents which are completely different from those of erosion are few in number but complex in their interactions. These agents include those that are atmospheric in nature whose components are oxygen, carbon dioxide and water vapour which play a vital role in rock decomposition. Other atmospheric components are temperature changes and precipitation which greatly influence the physical disintegration of the rocks. The biotic agents play a dual role of causing the chemical decomposition and the physical disintegration of rocks.
The total effect of the weathering agents is influenced by a variety of other factors. These include the nature and the structure of the rock, the size of the rock openings and how abundance they are in the rock and the surface configuration of the rock.

Mass movement (wasting) on the other hand refers to processes that cause the movement of earth’s materials from a high elevation downslope under the influence of gravity. The materials which are involved in mass movement are variable. The size of such material cause a significant influenced because, the larger the materials, the more immediate and pronounced the effect of their movement downslope.
The facilitators of mass movement include water, clay, tectonic instability and undermining due to local erosion. Water serves as a lubricant. Clay provides a slippery surface while tectonic instability such as earthquake and earth tremor set up vibrations that destabilize cohesion of materials.
Undermining due to local erosion attacks the base of materials and forces the materials at the upper slope to trip down. Mass movement is categorized.

While some of the movements are termed as rapid and conspicuous others are slow and gradual. Listing these types of mass movements from the most rapids down to the slowest, the major types of mass movements are: