Weathering erosion and deposition play an essential part in shaping Earth’s landscape. Harder rocks erode more slowly while soft rock erosion occurs at an exponentially faster rate.
Water can erode rocks and form incredible landforms like the Grand Canyon, while also causing problems like potholes in sidewalks.
Erosion can be caused by wind, gravity, ice and chemical reactions; wind and water then carry this sediment to its new locations.
Water
Water is one of the primary forces sculpting Earth’s landscape. Water flowing across land erodes away small pieces from it and deposits them somewhere else, such as in rivers or beaches.
Water can contribute to both physical and chemical weathering. Physical weathering occurs through heating and cooling cycles, freezing/thawing cycles, crystal growth in rocks, etc. Chemical weathering alters minerals within rocks by changing their chemical structures; acid rain causes limestone dissolution while iron rusts over time.
Plant roots can also play an active part in physically weathering rocks; their roots penetrate even the most minute cracks to widen them over time. Ice also acts as a physical weathering agent, melting and refreezeing to create unique rock shapes seen at Scotts Bluff National Monument.
Wind
Water, wind, glaciers (glaciers), and gravity are the major forces that shape Earth’s surface and landforms. Each of these forces can lead to weathering or erosion of rocks or materials which then stop moving resulting in deposition or depositional.
Wind erosion forms rocks in some environments such as deserts and coastal beaches by blowing sand into them from windstorms and scratching their surfaces with its presence, wearing down their surfaces over time through a process known as abrasion – creating features such as dunes.
Wind and ice can also transport eroded sediment from one location to the next, depositing it and creating features like river beds. The speed at which this happens depends on how erodible the soil is; hard aggregates made up of particles resistant to erosion such as clods can help slow the rate at which soil moves.
Gravity
Gravity is the force that pulls down on rock particles, loosening and transporting them through weathering, erosion processes like wind, water or ice erosion. When this material lands it becomes sediment.
Sediment can be transported long distances by water or ice currents and deposited much closer to its source, or it could travel miles away by moving along rivers and glaciers. Geologists use roundness measurements of sediment grains as an indication of its deposition mechanism; more rounded grains indicate transport over greater distances or energetic erosion processes.
Erosion is a gradual process; most weathering and erosion happens over a span of many decades or millions of years. But sometimes erosion happens much quicker; road crews are familiar with mechanical weathering which produces splits in roads or sidewalks due to rainwater runoff, expansion of ice sheets or tunneling plant roots.
Chemical Reactions
Weathering is an ongoing process that helps shape Earth’s rocky landscape. It happens when rocks and minerals are broken down by elements such as water, ice, acids, salts, plants, gravity changes and temperature shifts, leading to their breakdown and eventual displacement through erosion and deposition elsewhere – whether nearby as in valleys or thousands of miles away such as through rivers.
Chemical weathering is the predominant form of weathering in warm and humid environments. It occurs when water, reactants and soil dissolve ions from bedrock which then disassemble it further. Minerals with higher crystallization rankings on Bowen Reaction Series tend to be more resistant than those lower down on this list to chemical weathering.
Sediment
Sediments are loose rocks and other materials that can be transported by wind, water, or ice and can eventually settle to form sedimentary rocks. When transported over long distances and deposited they may form sand or silt deposits which then compact under certain circumstances to form rock layers known as sedimentary rock strata; this process is known as lithification.
Natural processes (mechanical weathering) and human activities, including agriculture, logging and construction activities contribute to increased sediment entry into river systems 10.
Excessive sediment levels in a stream can block sunlight and damage native water plants while producing unappetizing drinking water. Furthermore, sediment is known to contain numerous pollutants including metals in solution or adsorbed onto organic matter (e.g. dissolved iron) as well as persistent bioaccumulative toxics (PBTs).