Carbonation is the mixing of water with carbon dioxide to make carbonic acid. This type of weathering is important in the formation of caves. Dissolved carbon dioxide in rainwater or in moist air forms carbonic acid, and this acid reacts with minerals in rocks.
Chemical weathering. Chemical weathering occurs when there are changes in the chemical compositions of the rock or minerals from exposure to the environment. Chemical weathering includes chemical changes that may decompose, dissolve or break down various parts of the rock or other landform.
Physical weathering is caused by the effects of changing temperature on rocks, causing the rock to break apart. The process is sometimes assisted by water. There are two main types of physical weathering: Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.
Frost wedging is a type of mechanical weathering caused by frost and ice. Water expands when it freezes, and repeated cycles of freezing and thawing slowly weaken the structural integrity of porous and cracked rocks. Over time, frost wedging enlarges tiny cracks into huge fissures. The fissures ...
Chemical weathering is the process by which rocks are broken down by chemical reactions. There are different types of chemical weathering. Hydrolysis is the chemical breakdown of a substance when combined with water. The most common example of hydrolysis is feldspar in granite rocks changing to clay. Oxidation is the reaction of a substance with oxygen.
Oxidation is the reaction of a substance with oxygen. This is the process that causes rust. When iron in rocks reacts with oxygen, it forms iron oxide, which weakens the rock. Carbonation is the mixing of water with carbon dioxide to make carbonic acid. This type of weathering is important in the formation of caves.
However, abrasion is only one type of physical weathering that can break rocks into smaller fragments. Other types of physical weathering are ice wedging, exfoliation and thermal expansion. Similarly, the decomposition of rocks also can occur through chemical weathering.
Mechanical weathering pushes apart all joints in the exposed rock and breaks it into smaller pieces. Ice is a major weathering agent. Water expands 9 percent as it freezes and creates large forces that push apart joints on a rock’s surfaces. Root and vegetation growth exert the same pressure.