Weathering describes the breaking down or dissolve of rocks and minerals ~ above the surface ar of the Earth. Water, ice, acids, salts, plants, animals, and changes in temperature are all agents the weathering.
You are watching: Chemical weathering processes are particularly effective on limestone landscapes, forming
Weathering explains the breaking under or dissolve of rocks and minerals on the surface of the Earth. Water, ice, acids, salts, plants, animals, and changes in temperature room all agents the weathering.
Once a rock has been damaged down, a procedure called erosion transports the bits the rock and also mineral away. No absent on planet is hard enough to stand up to the forces of weathering and also erosion. Together, this processes sculpted landmarks such as the grand Canyon, in the U.S. State of Arizona. This substantial canyon is 446 kilometers (277 miles) long, as lot as 29 kilometers (18 miles) wide, and 1,600 meter (1 mile) deep.
Weathering and also erosion constantly adjust the rocky see of Earth. Weathering wears away exposed surfaces over time. The length of exposure frequently contributes come how fragile a rock is come weathering. Rocks, such together lavas, that room quickly hidden beneath various other rocks room less vulnerable to weathering and erosion than rocks that space exposed to agents such together wind and also water.
As that smoothes rough, sharp rock surfaces, weathering is regularly the first step in the production of soils. Small bits of weathered minerals mix v plants, animal remains, fungi, bacteria, and also other organisms. A single kind of weathered rock regularly produces infertile soil, if weathered products from a repertoire of rocks is richer in mineral diversity and also contributes to much more fertile soil. Soils species associated with a mixture of weathering rock incorporate glacial till, loess, and alluvial sediments.
Weathering is often divided into the procedures of mechanically weathering and chemical weathering. Organic weathering, in which life or once-living organisms contribute to weathering, deserve to be a part of both processes.
Water, in either fluid or solid form, is often a vital agent of mechanical weathering. Because that instance, liquid water have the right to seep right into cracks and crevices in rock. If temperatures drop low enough, the water will freeze. When water freezes, that expands. The ice then works as a wedge. It gradually widens the cracks and splits the rock. As soon as ice melts, liquid water performs the act of erosion by transferring away the small rock fragments lost in the split. This specific process (the freeze-thaw cycle) is referred to as frost weathering or cryofracturing.
Temperature alters can also contribute to mechanical weathering in a procedure called thermal stress. Transforms in temperature cause rock to broaden (with heat) and also contract (with cold). Together this wake up over and also over again, the framework of the rock weakens. Over time, the crumbles. Rocky desert landscapes are particularly vulnerable to heat stress. The outer layer of desert rocks undergo repeated stress as the temperature alters from day to night. Eventually, external layers flake off in slim sheets, a process called exfoliation.
Exfoliation contributes to the development ofbornhardts, among the many dramatic functions in landscapes developed by weathering and erosion. Bornhardts are tall, domed, diverted rocks often found in tropical areas. Sugarloaf Mountain, an above landmark in Rio de Janeiro, Brazil, is a bornhardt.
Changes in push can likewise contribute come exfoliation due to weathering. In a procedure called unloading, overlying products are removed. The basic rocks, exit from overlying pressure, have the right to then expand. As the rock surface expands, that becomes fragile to fracturing in a process called sheeting.
Another kind of mechanically weathering occurs once clay or other products near absent absorb water. Clay, an ext porous 보다 rock, deserve to swell v water, weathering the surrounding, harder rock.
Salt also works come weather absent in a procedure called haloclasty. Saltwater occasionally gets into the cracks and pores of rock. If the saltwater evaporates, salt crystals room left behind. Together the crystals grow, they put press on the rock, progressively breaking it apart.
Honeycomb weathering is associated with haloclasty. As its surname implies, honeycomb weathering defines rock formations with hundreds or also thousands the pits created by the expansion of salt crystals. Honeycomb weathering is typical in seaside areas, wherein sea sprays constantly pressure rocks to interact with salts.
Haloclasty is not restricted to seaside landscapes. Salt upwelling, the geologic process in which underground salt domes expand, can add to weathering the the overlying rock. Frameworks in the old city of Petra, Jordan, were made unstable and often fell down due come salt upwelling from the floor below.
Plants and also animals can be agents of mechanical weathering. The seed of a tree might sprout in soil the has built up in a cracked rock. Together the roots grow, lock widen the cracks, ultimately breaking the rock right into pieces. Over time, trees can break personally even big rocks. Even little plants, such as mosses, can enlarge small cracks as they grow.
Animals the tunnel underground, such together moles and prairie dogs, likewise work to rest apart rock and soil. Other pets dig and trample rock aboveground, resulting in rock to gradually crumble.
For instance, carbon dioxide from the air or soil occasionally combines with water in a process called carbonation. This produces a weak acid, referred to as carbonic acid, that have the right to dissolve rock. Carbonic acid is especially efficient at dissolving limestone. As soon as carbonic mountain seeps through limestone underground, it deserve to open up vast cracks or hollow out huge networks of caves.
Carlsbad Caverns nationwide Park, in the U.S. State of brand-new Mexico, includes more than 119 limestone caves produced by weathering and also erosion. The biggest is called the big Room. With an area of about 33,210 square meters (357,469 square feet), the huge Room is the dimension of 6 football fields.
Sometimes, chemical weathering dissolves huge portions that limestone or various other rock ~ above the surface ar of the planet to type a landscape dubbed karst. In these areas, the surface rock is pockmarked through holes, sinkholes, and also caves. Among the world’s most spectacular instances of karst is Shilin, or the stone Forest, near Kunming, China. Numerous slender, spicy towers of weathering limestone rise from the landscape.
Another kind of chemistry weathering functions on rocks that contain iron. This rocks revolve to rust in a process called oxidation. Rust is a compound produced by the communication of oxygen and iron in the presence of water. Together rust expands, that weakens rock and helps rest it apart.
Hydration is a form of chemical weathering in i m sorry the chemical bonds the the mineral are readjusted as it interacts with water. One circumstances of hydration occurs together the mineral anhydrite reacts through groundwater. The water transforms anhydrite into gypsum, among the most usual minerals on Earth.
Another familiar form of chemical weathering is hydrolysis. In the process of hydrolysis, a brand-new solution (a mixture of 2 or much more substances) is formed as chemistry in rock connect with water. In numerous rocks, for example, salt minerals communicate with water to form a saltwater solution.
Hydration and also hydrolysis add to flared slopes, one more dramatic instance of a landscape created by weathering and erosion. Flared slopes room concave rock formations periodically nicknamed “wave rocks.” their c-shape is greatly a an outcome of subsurface weathering, in i m sorry hydration and hydrolysis wear far rocks beneath the landscape’s surface.
Living or once-living biology can likewise be agents of chemistry weathering. The decaying remains of plants and also some fungi kind carbonic acid, which have the right to weaken and dissolve rock. Some bacteria can weather rock in bespeak to access nutrients such together magnesium or potassium.
Clay minerals, including quartz, are among the most usual byproducts of chemical weathering. Clays make up about 40% that the chemicals in all sedimentary rocks ~ above Earth.
For example, specific kinds of wait pollution boost the rate of weathering. Burning coal, natural gas, and petroleum releases chemicals such as nitrogen oxide and also sulfur dioxide right into the atmosphere. As soon as these chemicals incorporate with sunlight and moisture, they change into acids. They then fall earlier to earth as mountain rain.
Acid rain swiftly weathers limestone, marble, and also other type of stone. The impacts of mountain rain can frequently be checked out on gravestones, make names and other inscriptions impossible to read.
Acid rain has additionally damaged plenty of historic buildings and also monuments. Because that example, in ~ 71 meter (233 feet) tall, the Leshan giant Buddha at mountain Emei, China is the world’s largest statue of the Buddha. The was sculpted 1,300 years ago and sat unharmed for centuries. Creative drainage mechanism mitigates the natural procedure of erosion. However in recent years, acid rain has turned the statue’s sleep black and made several of its hair crumble and fall.
Weathering by water"s freeze-thaw cycle has separation this absent in two.
Photograph by George F. Mobley, nationwide Geographic
Spheroidal weathering is a type of chemistry weathering that occurs as soon as a rectangular block is weathered from three sides in ~ the corners and from 2 sides follow me its edges. It is likewise called “onion skin” weathering.
Weathered MountainsThe Appalachian mountains in east North America when towered much more than 9,000 meter (30,000 feet) high—taller 보다 Mount Everest! Over countless years, weathering and erosion have worn them down. Today, the highest possible Appalachian top reaches simply 2,037 meters (6,684 feet) high.
chemical compound the reacts through a base to type a salt. Acids have the right to corrode some natural materials. Acids have pH levels lower than 7.
precipitation through high levels of nitric and sulfuric acids. Mountain rain can be manmade or take place naturally.
process in which living or once-living organisms contribute to the fragmentation of rocks and also minerals (weathering).
(c. 563-483 BCE) Indian prince, spiritual leader, and founder the the buddhist religion. Likewise called Prince Siddhartha and also Gautama Buddha.
process changes the composition of rocks, frequently transforming them when water interacts with minerals to create various chemistry reactions.
chemical weathering procedure in which the freeze-thaw bicycle of ice cracks and disintegrates rock. Also called frost weathering.
type the mineral that is clear and, once viewed under a microscope, has a repeating pattern of atoms and molecules.
process that rocks crumbling as result of rain, wind, or other atmospheric conditions. Also called mechanical weathering and physical weathering.
C-shaped landform consist of of a concave rock wall formed by weathering and erosion the subsurface rocks. Likewise called a “wave rock.”
chemical weathering procedure in i beg your pardon the freeze-thaw bicycle of ice cracks and also disintegrates rock. Also called cryofracturing.
stone noting a person"s funeral place, frequently engraved with the person"s name and also dates that birth and also death.
type that sedimentary rock mostly made that calcium carbonate from shells and also skeletons of maritime organisms.
process of rocks crumbling as result of rain, wind, or various other atmospheric conditions. Also called physical weathering.
chemical procedure of a problem combining with oxygen to readjust the substance"s physical and molecular structure.
process that rocks crumbling as result of rain, wind, or various other atmospheric conditions. Also called mechanically weathering.
part of a plant the secures that in the soil, obtains water and nutrients, and often shop food make by leaves.
structure formed as water evaporates indigenous a braided lake or sea. The staying salt is hidden by sediments, but eventually pierces v the rock, forming a hill.
type of physical weathering in which a solitary layer of absent is broken off. Also called contour weathering.
See more: Which Jovian Planet Does Not Have Rings And Jovian Moons, Rings And Jovian Moons
existing in the tropics, the latitudes between the Tropic the Cancer in the north and the Tropic that Capricorn in the south.
join our ar of educators and receive the latest information on national Geographic"s sources for you and also your students.