Weathering is a series of disintegration and decomposition of the surface rock in the earth’s crust under the influence of the atmosphere, water and temperature changes and biological activities. Generally divided into three categories: physical weathering, chemical weathering, and biological weathering.

Physical weathering: also known as mechanical weathering, is the most simple of weathering, rock surface and internal in the diurnal and seasonal changes in temperature conditions does not occur simultaneously, thermal expansion and contraction, resulting in a kind of tension, so that the rock crack, on the other hand, the different mineral expansion system different number, different colors, different sizing, destruction of mineral combination of tension, promote rock disaggregation.

Chemical weathering: the mineral composition of rocks, in the role of oxygen, carbon dioxide and water, often a chemical decomposition of the role of the production of new substances. Some of these substances are dissolved in water, with the loss of water, and some are not dissolved substances remain in situ. This effect is chemical weathering.

Biological weathering: the destruction of the rock and mineral in the life activity of the organism. Such as the growth of plant roots, the activity of the cave animals, the decomposition of the decomposition of the decomposition of the formation of the decomposition of the rock after the death of the plant body, can change the state and composition of the rock.