Mechanical weathering includes processes that fragment and disintegrate rocks into smaller pieces without changing the rock's mineral composition
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chemical weathering - The process of chemical weathering generally occurs in the soil where water and minerals are in constant contact. Agents of weathering are oxygen, air pollution, water, carbonic acid, and strong acids. They combine with the minerals in rocks to form clays, iron oxides, and salts, which are the endpoints of chemical weathering.


This photograph shows differential weathering of a fractured rock surface. Water has preferentially gained access to the large fractures running from upper left to lower right and has weathered these areas faster than the rock face. The pockmarked surface represents an intensely fractured part of the rock that was later filled with silica. Silica is harder than the original rock, so as the rock weathers away, the silica, marking the fracture lines, stands out in bold relief.
This photograph shows differential weathering of a fractured rock surface. Water has preferentially gained access to the large fractures running from upper left to lower right and has weathered these areas faster than the rock face. The pockmarked surface represents an intensely fractured part of the rock that was later filled with silica. Silica is harder than the original rock, so as the rock weathers away, the silica, marking the fracture lines, stands out in bold relief.

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