Weathering, erosion and deposition are natural processes that reshape rocks into ever-shifting landscapes. Water is one of the main agents of erosion as it reshapes terrain while carrying sediments along floodplains.
Steep slopes can erode quickly, leading to landslides. Rain, ice and wind also play a part in erosion; when it forms in cracks it acts like a wedge to split rock away.
Physical Weathering
Natural forces continually shape and smooth rocks to produce ever-evolving landscapes, from water erosion and weathering agents such as raindrops to temperature swings and plant life causing its leaves to change, to plant roots moving underfoot or changes in temperature causing temperature fluctuation and temperature variations to erosion processes that transport bits of rock away. No rock is strong enough to withstand these forces which slowly carve landmarks like Arizona’s Grand Canyon.
Physical weathering fragments rocks into smaller chunks, creating more surface area exposed to chemical weathering processes – similar to how sugar lumps dissolve more rapidly in water than their granular counterparts.
Frost wedging is one form of physical weathering. When water seeps into cracks in rocks and freezes, expanding as it freezes it exerts pressure from within to eventually break apart the rock. Plant roots also contribute to physical weathering by growing into cracks to enlarge them – known as root wedging. Animal burrowing under ground may also have an impactful physical weathering impact as they break up rocks and stir sediments around.
Chemical Weathering
Chemical weathering refers to many different forms of rock weathering processes that alter its composition by breaking it down chemically or physically, with limestone dissolving into sand and water by way of dissolution; some rocks containing iron become vulnerable due to oxygen’s interaction with their surroundings, weakening them further and speeding up rates of erosion.
Chemical weathering also occurs in environments with reduced temperatures and frozen rocks, known as cryofracturing or frost weathering. Water seeps into cracks in rocks before freezing and expanding when frozen; eventually this expands and splits them, which then disintegrates by erosion into fragments carried away by rivers or storms.
Mechanical and chemical weathering processes combine to sculpt Earth’s landscape into ever-evolving works of art. These natural forces are responsible for creations such as the Grand Canyon; but they also shape hillslope forms, influence sediment transport patterns, and regulate landscape morphology on a much smaller scale.
Physical Erosion
Physical weathering (or mechanical weathering), commonly referred to as mechanical weathering, involves dissolving rocks, minerals and soil without chemical changes occurring in them. It can occur due to heating and cooling cycles, frost or crystal wedging processes, plant roots contacting with soil surface in burrowing animals’ dens or collision of rock pieces during movement.
Erosion occurs when weathering causes tiny pieces to dislodge from their original spots and be carried off elsewhere by natural forces like erosion. Erosion can occur slowly over time such as when rocks shift due to expansion of ice or quickly like with mudslides.
Erosion occurs over an extended period, creating landforms. Water, wind, glaciers and gravity are the main forces behind erosion; gravity helps sediment like boulders or sand move downward and be deposited; over time these deposits build up into mountains or rivers. Erosion also serves to remove materials such as soil, chemicals fertilizers and pesticides from sites that could otherwise harm the environment – leading to environmental disasters like oil spills.
Chemical Erosion
Physical processes used to break down rocks and minerals can result in chemical weathering on their surfaces. Water plays an essential role in this process by seeping through cracks in rocks or deposits of mineral deposits; when combined with acids produced by lichens, bacteria or decaying plants, this water can interact with materials within rocks to cause reactions that alter them permanently.
Weathering effects can be quite dramatic. In areas with carbonate rocks like limestone that dissolves in acidic groundwater, such as those located along a coastal region, an area known as karst may form, filled with caves, sinkholes and other features.
Physical and chemical weathering combine to form sediments, which are then carried away by erosion. They may deposit near their source of weathering or many miles away depending on how quickly they travel. Human activities can accelerate these natural processes: air pollution increases the rate at which rocks break down while the burning of fossil fuels speeds up weathering and erosion processes.