The process of physical fragmentation and chemical dissolution of solid rock, on the surface of the earth, is termed as weathering. In physical weathering the exterior of the rock gets decayed and disintegrates into smaller parts without destroying the characteristics or composition of the rock. In contrast to this, chemical decomposition alters the composition of the rock by altering the properties of its components. These two weathering processes work in a tandem and consistent manner to form debris. The removal of this debris by natural mechanisms such as rivers, glaciers, waves, and winds is termed as erosion.
The process of weathering makes rocky material into smaller pieces and the process of erosion changes their location (What’s the difference between weathering and erosion? , 1999). The process of weathering causes alterations to the surface layers. The outer layers of a rock expand due to the heat of the sun and this causes them to separate from the inner layers of the rock. There may be various minerals present in rocks and the differential expansion of these minerals results in the collapse of the rock. When the weather is very cold, the water in the pores of the rock expand on freezing due to the frost.
Rain also contributes to the process of weathering of rocks. Rain water absorbs carbon dioxide in the atmosphere and then forms carbonic acid, which disintegrates some minerals. Granite contains Feldspar, a mineral that is changed into clay due to rain water. Basalt has minerals that unite with oxygen and water to form iron oxide. Plants also contribute to weathering as their roots can create fissures in rocks (WEATHERING AND EROSION ). Erosion is often considered to be an action that breaks down rocks into smaller pieces. It involves the transportation of small pieces of rocks from their point of origin.
The process of erosion starts after the rocks have been broken into small pieces by the process of weathering, or rocks disintegrate due to abrasion caused by other small pieces of rock driven by water, wind or mechanical means (Wood, 2004 ). Chemical reactions cause the minerals present in rocks to disintegrate. This results in the formation of smaller pieces of rock, which is termed as chemical weathering. Normally chemical weathering deteriorates the bonding of elements in a rock and this action accelerates the process of mechanical weathering. Pieces of rock further break down into smaller pieces as they collide with other pieces of rock.
The effect of these two processes is that vital components of a local environment could be destroyed. Quite some effort has to be expended in order to counter the harmful effects of these processes, for instance in coastal areas, seawalls have to be constructed to protect the beach from depletion due to the continuous battering received from the sea waves. Moreover, in rivers, sedimentation could clog the free flow of the river and such an eventuality could be countenanced by restoring native vegetation, which mitigates the deleterious effects of erosion.
References
WEATHERING AND EROSION . (n. d. ). Retrieved May 23, 2007, from http://www. scarborough. k12. me. us/high/projects/geoscience4/sbergg/erosion. htm What’s the difference between weathering and erosion? . (1999, November 22). Retrieved May 23, 2007, from http://www2. nature. nps. gov/GEOLOGY/usgsnps/misc/gweaero. html Wood, D. (2004 ). The New Wider World Coursemate for Standard Grade Geography. Nelson Thornes. ISBN: 0748790829. P. 92.