Everyday we experience the results of weathering erosion and deposition. When sediment washes from rivers into other locations, for instance when sand or boulders wash out of rivers they end up somewhere else in nature.
Weathering refers to the process of breaking down rocks and minerals through erosion and deposition. Weathered material moves across land masses as erosion takes place while deposition involves its final deposit into one location.
Physical
Physical weathering refers to the gradual dissolution and degradation of rocks and minerals on Earth’s surface through various means such as water, ice, salts, plants/animals/temperature changes etc. Once rocks have been broken down into smaller particles by physical weathering processes they become subject to erosion which transports them away into our planet’s soils.
Mechanical erosion is the most frequently-seen form of physical weathering. This happens when rocks are worn away by physical forces such as flowing water or wind erosion, eventually breaking down into smaller and smaller pieces that form sediments.
Physical weathering assists chemical weathering by exposing more of the surface area of rocks to the environment; for instance, sugar lumps dissolve faster due to their larger surface area. Physical weathering also accelerates chemical weathering by loosening bonds that bind rocks together – especially important when dealing with harder-to-break apart types such as igneous and metamorphic rocks that can be more challenging to break apart chemically.
Chemical
Weathering is the process by which rocks and minerals are broken down through interaction between water, salts, acids and ice, animals and plants as well as changes in atmospheric pressure and temperature.
Chemical weathering can also contribute to erosion by disrupting the physical structure of rocks and minerals. Iron found within rocks may combine with oxygen in the air to form rust that then flakes away nearby rocks, while carbonic acid produced from burning coal, oil or natural gas can produce acid rain that weakens and dissolves rock formations.
Mechanical and chemical weathering combine to form detrital sedimentary rocks such as limestone or sandstone. Their formation involves three steps: lithification, compaction and deposition. When loose particles of bedrock, called clasts, are broken down by mechanical weathering they are carried via erosion to new locations where they are deposited before gravity, wind or ice remove enough energy from it for it to move downhill again.
Biological
Weathering by biological means is of vital importance because living organisms play an integral role in its acceleration through organic compounds like acids and humic substances produced by living organisms that contribute organic acids, humic substances and bioerosion. Lichens on rock surfaces promote cracking by producing chemicals which weaken and dissolve minerals; additionally these lichens form a symbiotic relationship with fungi which aid in breaking down rocks through metabolic processes like acid production and mineral solubilization.
Fungi release siderophores that attach themselves to metals in the soil and exchange cations for hydrogen ions; this chemical process leaves soil more acidic while also enabling certain fungi to chemically weather rocks.
Biologic weathering processes play a key role in shaping landscapes by means of weathering through plants’ growing into cracks in rocks and pushing away flakes of stone as they expand. Furthermore, plant roots cause chemical and physical weathering through their abrasive actions; many new approaches have been utilized over the last decade to incorporate biological processes into weathering rate estimates.
Environmental
Weathering and erosion continuously shape Earth’s surface. The type of rock exposed and its environmental conditions determine how it weathers; rocks along seashores often erode more easily due to wave action and tides; similarly chemical weathering typically takes place when present alongside water as well as bacteria, fungi, plants etc.
Water is the main cause of weathering and erosion on the Earth’s surface and underground, acting upon rocks and minerals in their entirety, including salts, acids, ice cubes and even living organisms.
Gravity forces all particles of weathered rock to move downhill and eventually settle at the base of slopes, where they are then deposited. Wind and snow may transport away smaller fragments. This process has been occurring over billions of years and plays an essential role in supporting ecosystems and wildlife while shaping natural resources available to us humans. Its name: Geologic Cycle