Chemical weathering

Chemical weathering is caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic. These chemical processes need water, and occur more rapidly at higher temperature, so warm, damp . Learn about the different types of chemical weathering ,. There are three types of weathering : mechanical, biological, and chemical.

Biological weathering is caused by the actions of plants and animals as they grow, nest, and burrow. When a rock is brought to the surface millions or billions of years after it has forme the original minerals that were crystallized deep in the crust under high pressures and temperatures are unstable in the surface environment and eventually break down. The primary agents in chemical weathering are water, oxygen, and . This is because water is important to many of the chemical reactions that can take place. Warmer temperatures are also more friendly to chemical weathering.

The most common types of chemical weathering are oxidation, hydrolysis and . There are hundreds of natural chemical processes and reactions within the rocks the change the composition and the structure of the rocks over time. Weathering occurs in situ (on site), that is, in the same place, with little or no movement, and thus should not be confused with erosion, which .

The kinds of changes that take place are highly specific to the mineral and the environmental conditions. Some minerals, like quartz, are virtually unaffected by chemical weathering , while. This is the decomposition of rocks due to chemical reactions occurring between the minerals in rocks and the environment. The examples below illustrate chemical weathering.

Water Water, and many chemical compounds found in water, is the main agent of chemical weathering. Feldspar, one of the most abundant . It alters rather easily during chemical weathering and thus is rare in sediments and sedimentary rocks. One stage in the weathering of biotite has resulted in some confusion. During chemical weathering , biotite tends to lose its elasticity and become decolorized to silvery gray flakes. After the physical breakup and chemical decay of exposed rocks by weathering , the loosened rock fragments and alterations products are carried away through the process of erosion.

Erosion relies on transporting agents such . Temperature an especially, moisture are critical . Sometimes, chemical weathering dissolves large regions of limestone or other rock on the surface of the Earth to form a landscape called karst. Igneous rock is one of the three main rock types, the others being . In these dramatic areas, the surface rock is pockmarked with holes, sinkholes, and caves. One of the worlds most spectacular examples of karst is Shilin, or the Stone Forest, near .

Change in phase (mineral type) and composition are due to the action of chemical agents.