Effects of Weathering and Erosion on the Geochemistry Of Rocks And Soils

Abstract

This paper seeks to find the effects of weathering on the geochemistry of rocks and soils. Weathering is characterized by physical disintegration and chemical decomposition of rocks. This is associated with structural transformation of the minerals which make up the rocks. Contact of rocks with either or both water and oxygen promote weathering. Weathering and erosion occur in the upper portion of the Earth’s crust and affects igneous, metamorphic and sedimentary rocks. The most common chemical elements in the crust are oxygen, silicon and aluminous and they are all prone to weathering. Also, the most common minerals are feldspars, quartz, pyroxenes and amphiboles and these, also, are prone to weathering. Weathering leads to changes in their chemical composition. After weathering, certain minerals disappear while new ones are created. This depends on the resistance of each mineral to weathering. The chemical processes involved in weathering are hydration, hydrolysis, solution, carbonation, oxidation and reduction. Weathering first destroys any relatively weak bonding agents before the products are further subjected to greater disintegration.Weathering leads to increased pH, leaching of alkaline earth cations and leaching of H4SiO4. In some cases, weathering leads to rust which is a reaction between Fe2+ containing compound, H2O and O2. Solution, carbonation and reduction all involves chemical reaction. With all these changes involving chemical reaction, weathering and erosion therefore has positive impact on the geochemistry of rocks and soils of the Earth’s crust.