weathering in geography

Physical (Mechanical) Weathering

This type of weathering occurs when rocks break apart without changing their chemical composition. It is mainly caused by temperature changes, pressure, water, ice, and biological activity

Frost Wedging

Water enters cracks in rocks, freezes, expands, and breaks the rock apart.

Thermal Expansion

Repeated heating and cooling cause rocks to expand and contract, leading to cracks and breakage.This physical weathering process occurs when rocks expand during heating and contract during cooling, resulting in stress and fractures.

exfoliation (Unloading)

is a type of physical weathering where layers of rock peel away due to reduced pressure when overlying materials are removed. This process can occur in areas such as mountain ranges after erosion.

Abrasion

is a type of physical weathering caused by the scraping, grinding, or wearing away of rocks and surfaces due to the action of wind, water, or ice. This process often leads to smoother surfaces and can result in the removal of rock material.

Biological Activity

is a type of physical weathering that occurs when plants, animals, or microorganisms interact with rocks. Root growth, burrowing animals, and microbial activity can contribute to the breakdown of rock material.

Chemical Weathering

is the process of breaking down rocks and minerals through chemical reactions, often involving water and atmospheric gases, leading to changes in mineral composition.

Oxidation

is a type of chemical weathering that involves the reaction of minerals with oxygen, often resulting in rusting of iron-rich rocks and an overall change in mineral structure.

Hydrolysis

Water reacts with minerals, forming new minerals and weakening the rock structure (e.g., feldspar turning into clay).

Carbonation

Carbon dioxide dissolves in water to form carbonic acid, which reacts with limestone and other carbonate rocks, dissolving them.

Acid Rain

Pollution causes rainwater to become acidic, which accelerates rock breakdown.

Biological Weathering (Chemical)

Plants and microorganisms produce acids that dissolve minerals in rocks.

Interplay of Physical and Chemical Weathering

Physical weathering increases the surface area of rocks, making them more vulnerable to chemical weathering. For example, frost wedging creates cracks that allow water and acids to penetrate deeper, accelerating chemical breakdown.