Chemical Weathering In Limestone And Granite

Both have been used as key building blocks over the centuries.

Chemical weathering in limestone and granite.

Water causes both mechanical weathering and chemical weathering. They are however very different in their composition appearances and uses. The grand canyon for example was formed to a large degree by the mechanical weathering action of the colorado river. Chemical weathering involves the decomposition of rocks due to chemical reactions between minerals such as calcite with water and gases in the atmosphere e g.

A gravestone made of granite will therefore resist fracturing cracking and chipping longer than a sandstone marker found in the same location. Weathering is the breakdown of rock by physical chemical or biological processes. Limestone also dissolves at relatively shallow depths underground forming limestone. Carbon dioxide from the respiration of animals and ourselves is one cause of increased carbon dioxide in the atmosphere.

Calcite is the major component of limestone typically more than 95 and under surface conditions limestone will dissolve to varying degrees depending on which minerals it contains other than calcite as shown in figure 5 12. Limestone areas are predominantly affected by chemical weathering when rainwater which contains a weak carbonic acid reacts with limestone. Carbon dioxide and sulphur dioxide. Granite is extremely hard and less affected by the freeze thaw cycle the forces of abrasion and the surface exfoliation processes that are all a part of physical weathering.

Mechanical weathering occurs when water drips or flows over rock for prolonged periods. Two important ones are rock salt and limestone. When these rocks dissolve the materials which make them up become ions in solution in the water and are carried away with it. Granite and limestone are two of the most common and widely distributed rocks on earth.

The little chunks of granite are weathering and accumulating in topographic lows. Chemical weathering can produce caves made of limestone some types of rock are not easily weathered by chemicals. 5 2 chemical weathering. For example granite and gabbro are hard rocks that are weathered only slowly.

This causes the limestone to dissolve.