Weathering, or wear and tear, refers to the wearing down of rocks and minerals by physical, chemical or biological means.
Physical weathering occurs when rocks deteriorate due to rainwater and other atmospheric factors. Liquid water may enter cracks in rocks, where temperatures drop and it freezes into solid ice formation that expands and widens cracks further.
Physical
Physical weathering refers to the breakup of rocks and minerals into smaller pieces without altering their chemical makeup, through either mechanical or chemical means. Water seeping into cracks and crevices of rock may cause it to split apart – an example of mechanical weathering; repeateing this action over time can result in large chunks breaking off or crumbling away entirely. Water can also freeze-thaw repeatedly weakening it even more each time – this type of weathering is known as frost weathering, spheroidal weathering or exfoliation.
Chemical weathering refers to the process of breaking down rocks by chemical changes in rainwater. Chemical changes in rainwater can accelerate erosion more rapidly than otherwise – for instance carbon dioxide in rainwater forms weak acids which facilitate faster erosion than would normally happen, acid rain produced from burning fossil fuels contains sulfuric and nitric acids which further accelerate chemical weathering processes, while plant roots, animal burrows, or bacterial decay all can have an effect.
Chemical
Chemical weathering, the process by which rocks and other materials break down chemically over time, occurs when exposed minerals in rocks come in contact with air and water, changing its chemical composition to become more fragile and susceptible to erosion.
Chemical weathering occurs through hydrolysis, oxidation and carbonation processes. For instance, when acidic rainwater comes in contact with granite, its feldspar crystals react with it and form clay minerals, weakening and eventually cracking it more likely than otherwise. This form of weathering tends to occur more in warm and wet climates.
Chemical weathering occurs when rocks containing iron are exposed to oxygen and begin to rust or corrode, an example of chemical weathering. Meanwhile, other minerals, like silicates, tend to be less vulnerable due to being more stable – they’re found in both igneous and metamorphic rocks, creating what’s known as karst landscapes with caves and sinkholes as a result.
Biological
Biological weathering refers to the breakdown and alteration of rocks by plants, animals and microorganisms – including plants roots – over time, helping shape Earth’s landforms. Plant roots penetrate cracks in rocks exerting pressure which breaks apart pieces while lichens which grow on rock surfaces produce acids which chemically change minerals within them; acid rain produced from burning coal, natural gas or petroleum can further corrode limestone, marble and other types of rock leaving names and inscriptions unreadable on gravestones.
Burrowing animals such as shrews, moles and earthworms contribute to biological weathering by creating holes in the ground that expose rock fragments to the elements. Birds foraging for seeds also play a part in weathering rocks by scratching and pecking at their surfaces – all this helps create soil for plants and animals to live on.
Human
Flexi Says: Human activities such as construction and mining can cause mechanical weathering, while chemical weathering occurs through activities like burning fossil fuels which release chemicals that break down into acids in the atmosphere and fall back down to Earth as raindrops, hastening chemical weathering faster and causing rocks to break apart more rapidly than normally would happen; this form of precipitation is known as acid rain which can damage buildings, statues and gravestones alike.
Arline Geronimus first proposed the concept of weathering in 1992 as part of her public health research. Weathering is defined as prolonged exposure to social adversity and marginalization leading to early biological aging in disadvantaged groups due to chronic stress response – such as elevated cortisol levels leading to hypertension and heart disease; weathering also results in shortened telomeres and inflammation within bodies – both processes common among racial minorities or people living in low socioeconomic status communities.