Chemical Weathering

Abstract

Chemical weathering of rocks is the most important geological process for soil formation and consists of an adjustment of rock-forming minerals to the prevailing conditions near the Earth’s surface by several chemical processes (solution, hydration, hydrolysis, carbonation, oxidation, reduction, and chelation) that are ruled by the chemical action of water with dissolved substances. Chemical reactions can become more effective when the water is slightly acidic or/and when the surface area of the rock increases, leading to mineral transformation and chemical decomposition of rock, thereby contributing to the decay of rock. The products resulting from the various phases of weathering are essentially composed of secondary minerals and more resistant primary minerals, the residual soils. Chemical weathering and physical weathering work together; however, the predominance of each one depends on the climatic conditions, geomorphology, lithol-ogy, and the presence of vegetation.