Weathering is the gradual breaking down of rocks into smaller pieces without altering their chemical makeup, due to changes in temperature; when rocks expand when heated up and contract when chilled down again, breaking apart into individual fragments.
Erosion causes rocks to erode away and form new landforms such as canyons, islands and beaches. Furthermore, erosion gives limestone and chalk their distinctive cliffs.
Over time, various physical factors like freezing and thawing, wind, rain, waves and gravity wear away rock surfaces through erosion to form today’s rough rocky landscapes.
Weathering of rocks depends on both temperature and chemical makeup; for instance, limestone is more susceptible to chemical weathering than granite. Rainwater can become acidic as it absorbs carbon dioxide from the air and dissolve minerals found within these rocks – including those present in limestone rocks such as it.
Water that seeps into rocks’ cracks may expand when frozen, pushing apart their cracks through frost wedging or root wedging processes. Frost wedging occurs when water freezes within its pores and expands, pushing apart cracks in a process called frost wedging; plant roots growing into those cracks also contribute to physical weathering by expanding them as part of root wedging; both these processes help create soil composed of round rock fragments and other materials.
Chemical weathering involves chemical reactions between rocks and elements such as water. Water plays an essential part in chemical weathering as it reacts with rocks to form various minerals; water reacting with granite feldspar crystals converts them to clay minerals when exposed to rainwater, while carbon dioxide reacts with rainwater to form carbonic acid; this weak acid dissolves rocks easily as well as dissolving limestone into caves such as Carlsbad Caverns in New Mexico.
Oxygen can react with iron in a process known as oxidation to form rust and change its color and make rocks more fragile. Chemical weathering also occurs when porous substances like clay come into contact with rocks – they absorb rainwater and expand with it, eventually eroding harder rocks around them. Furthermore, bacteria have even been shown to chemically weather rocks; mycorrhizal fungi released from tree roots have shown to impact mineral stability while providing inorganic nutrients to their host plant roots.
Biological weathering refers to the process by which rocks are decomposed by organisms – animals, plants and microorganisms like bacteria – using physical or chemical weathering processes as catalysts. It works hand in hand with both forms of weathering.
Fungal organisms living within lichen (an alliance between algae and fungi) release chemicals which dissolve rock minerals, creating holes and fissures on their surfaces – which may subsequently accelerate physical weathering processes.
Examples of biological weathering include plant roots penetrating the soil or animals burrowing underground; this action creates a humid chemical microenvironment which accelerates chemical and physical weathering processes.
Biological weathering also plays a role in Black and Brown communities, where stressors such as persistent prejudice and economic inequality exacerbate biological aging more quickly than in White communities. This delays healing processes in the body and eventually leads to chronic diseases like high blood pressure, heart disease and diabetes – the only way to stop such biological weathering being addressed are by addressing its source: social and economic disparities among Black and Brown people.
Humans can significantly alter the type and rate of weathering. Burning fossil fuels releases chemicals into the air which eventually turn to acids before eventually falling back down on Earth as acid rain. Deforestation exposes rocks to intense sun light which can cause them to exfoliate or fracture; planting trees provides shelter to these rocks while decreasing sun exposure.
Mycorrhizal fungi that are associated with tree roots also release inorganic nutrients from minerals that help weather them; this process is commonly known as biological weathering.
Psychosocial factors also appear to play an integral role in weathering. A study that explored this relationship found depression symptoms correlated to weathering (the difference between chronological age and biological age), though this relationship became attenuated when adjusted for socioeconomic status – suggesting other forms of psychological stressors could take their toll in other ways.