Weathering erosion deposition sculpt the Earth’s rock into ever-evolving works of art – an example being the Grand Canyon and ice wedging (whereby expanding ice splits rocks).
Erosion is a physical process that uses water, wind, ice or gravity to move sediment away from its point of origin. Water is by far the strongest agent of erosion.
Soil Formation
Soils are formed through the weathering and deposition of bedrock. Their characteristics and fertility depend on factors like their parent materials, environment and duration of weathering processes which transform them into soil.
Soil formation depends on many different factors, including physical weathering (disintegration of rocks without chemical changes) and chemical weathering (fractional dissolution of minerals). Both processes depend heavily on local environmental factors like climate, landscape position, and vegetation.
Soils can also be altered by the different species that occupy it. Plant roots spread into cracks and crevices while microorganisms break apart rock fragments. Organic material increases soil’s capacity to hold onto water and nutrients and slow erosion while permitting plants to absorb more sunlight while speeding up deeper weathering processes faster than mechanical weathering – this amount of organic matter in soil is known as its “humus content.”
Landforms
Landforms found near us result from erosion, weathering and deposition altering Earth’s surface. Landforms form through interactions among various processes including physical, chemical and biological weathering as well as gravitational forces.
Resistance of rocks and minerals to erosion differs widely, creating distinctive landscape features. Sandstone is much more easily eroded than granite, leading to unique formations like sea arches and hoodoos.
Mechanical weathering processes include wind erosion, the freezing-thawing action of water, and, in extreme cases, disintegration by chemicals like acid rain or carbonic acid from decaying plants and fungi. Chemical weathering can alter rock composition by producing clay minerals.
Erosion may seem to occur slowly, but gravity has the power to create drastic change quickly. Gravity could quickly cause bits of soil to quickly move downhill over time creating sand dunes or cause large sections of land to suddenly collapse creating a landslide.
Sediment Deposition
Sediment transport refers to the movement of rock fragments, soil particles, organic material, and dissolved minerals across geologic terrain. The physical composition of sediment depends on geology; for instance glacial streams often carry large gravel particles while low-flow rivers collect more soil-based sediment 14. Sediment particles take shape from their environment: sharp corners on very angular particles can be worn away with abrasion during transportation; while their degree of rounding indicates both distance and time traveled 15.
River sediment deposits occur along its course in bars, floodplain deposits, deltas and alluvial fans. When storm activity increases significantly resuspension/erosion may take over; otherwise deposition may prevail 16.
Longer-term, sediment deposits eventually undergo lithification to create clastic sedimentary rocks through pressure-induced cementation of loose mineral grains into one large stone clump through pressure 17, essentially “gluing” them together under pressure 17. Mineral cementation also contributes to some sedimentary rocks like sandstone and limestone 18.
Pollution
Sediment pollution has the ability to disrupt multiple ecosystem services, including flood control, water filtration and biodiversity. The source of sediment pollution may be natural or human-induced; construction sites often contribute significantly to this issue with erosion from construction sites increasing the amount of sediment flowing off into rivers and lakes; leading to cloudy waters, algal blooms which deplete oxygen levels quickly depriving aquatic life of oxygen they need for survival and eventually killing off all life forms in its wake.
Gravity is the primary force responsible for transporting sediment downhill from slopes. It does so via creep, rock or debris falls and landslides as well as wind-blown sedimentation and, most significantly, flowing water.
Weathering occurs when water, ice, acids, salts, plants and animals interact to break down rocks and minerals into smaller parts. Chemical weathering alters molecular structures within rocks and soils – for instance when carbon dioxide from the air combines with water to form carbonic acid that quickly weathers limestone; or when oxygen reacts with metals such as iron to oxidize and form rust forming rust.