Weathering refers to the gradual breakdown of rocks and minerals located near Earth’s surface through chemical, physical and biological means.
Air and water are two primary agents of weathering. Oxygen reacts with carbon dioxide in raindrops to form acid raindrops that break down rock, weakening and disintegrating it over time.
Physical
Weathering, also known as erosion, refers to the process of breaking down and dissolving rocks and minerals on Earth’s surface through agents like water, ice, acids, salts, plants and animals as well as temperature changes. This process forms giant canyons like Grand Canyon.
The Rock Cycle refers to how different kinds of rocks form, disassemble and are transported by wind, rain and glaciers. Weathering plays an integral part in this cycle and includes three categories of weathering: physical, chemical and biological.
Physical weathering gradually breaks rocks apart into smaller and smaller pieces over time, through various processes such as frost wedging. Frost wedging occurs when water seeps into cracks in rock before freezing; expanding its cracks and eventually breaking it apart over time. Plant roots that burrow into rock cracks or animals that dig or tramp belowground can also contribute to physical weathering processes.
Chemical
Chemical weathering occurs when minerals in a rock undergo chemical change that weakens it and makes it more susceptible to erosion. Minerals react with water, oxygen and other substances to form new minerals which alter its composition; this process is often accelerated by warm temperatures and moisture.
Carbonic acid in rainwater, for instance, can slowly dissolve limestone and other types of rocks over time – leading to caves, springs and other features known as “karst topography.”
Chemical weathering occurs when iron in rocks combines with oxygen from the air to form rust, which corrodes away at its stone base. Human activities also play a part in chemical weathering; power plants that use coal as an energy source produce sulfur dioxide that mixes with nitrogen gases in the atmosphere to form acid rain that attacks stone, particularly soft sandstone.
Biological
As plants and animals move over rocks, they can cause weathering to take place. For instance, when their roots penetrate cracks in rocks they can widen. This process may either involve physical or chemical weathering processes.
Fungi are also key components of biological weathering. Encycorrhizal fungi have the power to penetrate cracks and voids in biotite minerals, physically distorting its lattice structure while aiding chemical weathering via dissolution and oxidation processes.
Biological weathering is one process that leads to soil formation, made up of various types of weathered rock particles mixed together. This form of weathering allows plants and other organisms to access vital mineral elements through biomineralization.
Human
Erosion is the gradual wearing away of rocks or materials, exposing underlying layers. Erosion can be caused by weathering factors like rain, wind, ocean waves, glaciers’ movement or gravity; or chemical pollution from burning fossil fuels which releases nitrogen oxide and sulfur dioxide into the atmosphere which interact with sunlight and moisture to form acid rain that quickly weathers limestone, marble and other kinds of stone; even making names and inscriptions on gravestones unreadable.
Black Lives Matter protesters and research have made it abundantly clear that persistent exposure to socioeconomic adversity, political marginalization, racism, and discrimination can lead to health problems, including the shortening of your telomeres that results in early health deterioration and biological ageing that exceeds chronological age. Scientists who study these societal stresses refer to it as weathering; biomarkers such as blood pressure reactivity or waist-to-hip ratio can help illuminate physiological mechanisms behind such disparities.