This article is about the scientific phenomenon of sedimentation. For sedimentation in the treatment of water and wastewater, see Sedimentation (water treatment).
Sedimentation is the deposition of sediments.[1] It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration, or electromagnetism. Settling is the falling of suspended particles through the liquid, whereas sedimentation is the final result of the settling process.
In geology, sedimentation is the deposition of sediments which results in the formation of sedimentary rock. The term is broadly applied to the entire range of processes that result in the formation of sedimentary rock, from initial erosion through sediment transport and settling to the lithification of the sediments. However, the strict geological definition of sedimentation is the mechanical deposition of sediment particles from an initial suspension in air or water.
Sedimentation may pertain to objects of various sizes, ranging from large rocks in flowing water, to suspensions of dust and pollen particles, to cellular suspensions, to solutions of single molecules such as proteins and peptides. Even small molecules supply a sufficiently strong force to produce significant sedimentation.
In geology, the term sedimentation is broadly applied to the entire range of processes that result in the formation of sedimentary rock, from initial formation of sediments by erosion of particles from rock outcrops, through sediment transport and settling, to the lithification of the sediments. However, the term is more particularly applied to the deposition of sediments, and in the strictest sense, it applies only to the mechanical deposition of sediment particles from an initial suspension in air or water. Sedimentation results in the formation of depositional landforms and the rocks that constitute the sedimentary record.[2] The building up of land surfaces by sedimentation, particularly in river valleys, is called aggradation.[3]
The rate of sedimentation is the thickness of sediment accumulated per unit time.[4] For suspended load, this can be expressed mathematically by the Exner equation.[5] Rates of sedimentation vary from less than 3 millimeters (0.12 in) for pelagic sediment to several meters per year in portions of major river deltas. However, long-term accumulation of sediments is determined less by rate of sedimentation than by rate of subsidence, which creates accommodation space for sediments to accumulate over geological time scales. Most sedimentation in the geologic record occurred in relative brief depositional episodes separated by long intervals of nondeposition or even erosion.[6]
An undesired increased transport and sedimentation of suspended material is called siltation, and it is a major source of pollution in waterways in some parts of the world.[7][8] High sedimentation rates can be a result of poor land management and a high frequency of flooding events. If not managed properly, it can be detrimental to fragile ecosystems on the receiving end, such as coral reefs.[9]Climate change also affects siltation rates.[10]
In estuarine environments, settling can be influenced by the presence or absence of vegetation. Trees such as mangroves are crucial to the attenuation of waves or currents, promoting the settlement of suspended particles.[11]
Gediz delta, showing a typical natural delta landscape
Sedimentation enhancing strategies are environmental management projects aiming to restore and facilitate land-building processes in deltas.[12]Sediment availability and deposition are important because deltas naturally subside and therefore need sediment accumulation to maintain their elevation, particularly considering increasing rates of sea-level rise.[13][14] Sedimentation enhancing strategies aim to increase sedimentation on the delta plain primarily by restoring the exchange of water and sediments between rivers and low-lying delta plains. Sedimentation enhancing strategies can be applied to encourage land elevation gain to offset sea-level rise.[15] Interest in sedimentation enhancing strategies has recently increased due to their ability to raise land elevation, which is important for the long-term sustainability of deltas.[12]
Chemistry
In chemistry, sedimentation has been used to measure the size of large molecules (macromolecule), where the force of gravity is augmented with centrifugal force in an ultracentrifuge.
When particles settling from a suspension reach a hard boundary, the concentration of particles at the boundary is opposed by the diffusion of the particles. The distribution of sediment near the boundary comes into sedimentation equilibrium. Measurements of the distribution yields information on the nature of the particles.[16][17]
Type 1 sedimentation is characterized by particles that settle discretely at a constant settling velocity, or by the deposition of Iron-Rich minerals to streamlines down to the point source. They settle as individual particles and do not flocculate (stick to each other) during settling. Example: sand and grit material
Type 2 sedimentation is characterized by particles that flocculate during sedimentation and because of this their size is constantly changing and therefore their settling velocity is changing. Example: alum or iron coagulation
Type 3 sedimentation is also known as zone sedimentation. In this process the particles are at a high concentration (greater than 1000 mg/L) such that the particles tend to settle as a mass and a distinct clear zone and sludge zone are present. Zone settling occurs in lime-softening, sedimentation, active sludge sedimentation and sludge thickeners.
^Jackson, Julia A., ed. (1997). "sedimentation". Glossary of geology (Fourth ed.). Alexandria, Virginia: American Geological Institute. ISBN0922152349.
^Paola, C.; Voller, V. R. (2005). "A generalized Exner equation for sediment mass balance". Journal of Geophysical Research. 110: F04014. Bibcode:2005JGRF..11004014P. doi:10.1029/2004JF000274.
^Blatt, Harvey; Middleton, Gerard; Murray, Raymond (1980). Origin of sedimentary rocks (2d ed.). Englewood Cliffs, N.J.: Prentice-Hall. pp. 30–31, 122–123. ISBN0136427103.
^ . blackwarriorriver.org. Archived from the original on 2009-12-21. Retrieved 2009-11-16.
^ "Siltation killed fish at Batang Rajang - Digest on Malaysian News". malaysiadigest.blogspot.com. Retrieved 2009-11-16.
^Victor, Steven; Neth, Leinson; Golbuu, Yimnang; Wolanski, Eric; Richmond, Robert H. (2006-02-01). "Sedimentation in mangroves and coral reefs in a wet tropical island, Pohnpei, Micronesia". Estuarine, Coastal and Shelf Science. 66 (3–4): 409–416. Bibcode:2006ECSS...66..409V. doi:10.1016/j.ecss.2005.07.025.
^ U.D. Kulkarni; et al. "The International Journal of Climate Change: Impacts and Responses » Rate of Siltation in Wular Lake, (Jammu and Kashmir, India) with Special Emphasis on its Climate & Tectonics". The International Journal of Climate Change: Impacts and Responses. Retrieved 2009-11-16.
^Van Santen, P.; Augustinus, P. G. E. F.; Janssen-Stelder, B. M.; Quartel, S.; Tri, N. H. (2007-02-15). "Sedimentation in an estuarine mangrove system". Journal of Asian Earth Sciences. Morphodynamics of the Red River Delta, Vietnam. 29 (4): 566–575. Bibcode:2007JAESc..29..566V. doi:10.1016/j.jseaes.2006.05.011.
^ abNicholls, R. J.; Hutton, C. W.; Adger, W. N.; Hanson, S. E.; Rahman, Md. M.; Salehin, M., eds. (2018). Ecosystem Services for Well-Being in Deltas: Integrated Assessment for Policy Analysis. Cham: Springer International Publishing. doi:10.1007/978-3-319-71093-8. ISBN978-3-319-71092-1. S2CID 135458360.
^Syvitski, J. P. (2008). "Deltas at risk". Sustainability Science. 3 (1): 23–32. doi:10.1007/s11625-008-0043-3. ISSN 1862-4065. S2CID 128976925.
^Giosan, L.; Constantinescu, S.; Filip, F.; Deng, B. (2013). "Maintenance of large deltas through channelization: Nature vs. humans in the Danube delta". Anthropocene. 1: 35–45. doi:10.1016/j.ancene.2013.09.001.
^Paola, C.; Twilley, R. R.; Edmonds, D. A.; Kim, W.; Mohrig, D.; Parker, G.; Viparelli, E.; Voller, V. R. (2011). "Natural Processes in Delta Restoration: Application to the Mississippi Delta". Annual Review of Marine Science. 3 (1): 67–91. Bibcode:2011ARMS....3...67P. doi:10.1146/annurev-marine-120709-142856. ISSN 1941-1405. PMID 21329199.
^"The Nobel Prize in Physics 1926". NobelPrize.org. 27 Nov 2021. Retrieved 27 November 2021.
^Piazza, Roberto; Buzzaccaro, Stefano; Secchi, Eleonora (2012-06-27). "The unbearable heaviness of colloids: facts, surprises, and puzzles in sedimentation". Journal of Physics: Condensed Matter. 24 (28): 284109. Bibcode:2012JPCM...24B4109P. doi:10.1088/0953-8984/24/28/284109. ISSN 0953-8984. PMID 22738878. S2CID 23309333.
^Coe, H.S.; Clevenger, G.H. (1916). "Methods for determining the capacities of slime-settling tanks". Transactions of the American Institute of Mining and Metallurgical Engineers. 55: 356.
January 20, 2023
sedimentation, this, article, about, scientific, phenomenon, sedimentation, sedimentation, treatment, water, wastewater, water, treatment, deposition, sediments, takes, place, when, particles, suspension, settle, fluid, which, they, entrained, come, rest, agai. This article is about the scientific phenomenon of sedimentation For sedimentation in the treatment of water and wastewater see Sedimentation water treatment Sedimentation is the deposition of sediments 1 It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier This is due to their motion through the fluid in response to the forces acting on them these forces can be due to gravity centrifugal acceleration or electromagnetism Settling is the falling of suspended particles through the liquid whereas sedimentation is the final result of the settling process In geology sedimentation is the deposition of sediments which results in the formation of sedimentary rock The term is broadly applied to the entire range of processes that result in the formation of sedimentary rock from initial erosion through sediment transport and settling to the lithification of the sediments However the strict geological definition of sedimentation is the mechanical deposition of sediment particles from an initial suspension in air or water Sedimentation may pertain to objects of various sizes ranging from large rocks in flowing water to suspensions of dust and pollen particles to cellular suspensions to solutions of single molecules such as proteins and peptides Even small molecules supply a sufficiently strong force to produce significant sedimentation Contents 1 Geology 1 1 Human enhanced sedimentation 2 Chemistry 3 Sedimentation equilibrium 4 Classification 5 See also 6 NotesGeology EditSee also Deposition geology Siltation In geology the term sedimentation is broadly applied to the entire range of processes that result in the formation of sedimentary rock from initial formation of sediments by erosion of particles from rock outcrops through sediment transport and settling to the lithification of the sediments However the term is more particularly applied to the deposition of sediments and in the strictest sense it applies only to the mechanical deposition of sediment particles from an initial suspension in air or water Sedimentation results in the formation of depositional landforms and the rocks that constitute the sedimentary record 2 The building up of land surfaces by sedimentation particularly in river valleys is called aggradation 3 The rate of sedimentation is the thickness of sediment accumulated per unit time 4 For suspended load this can be expressed mathematically by the Exner equation 5 Rates of sedimentation vary from less than 3 millimeters 0 12 in for pelagic sediment to several meters per year in portions of major river deltas However long term accumulation of sediments is determined less by rate of sedimentation than by rate of subsidence which creates accommodation space for sediments to accumulate over geological time scales Most sedimentation in the geologic record occurred in relative brief depositional episodes separated by long intervals of nondeposition or even erosion 6 An undesired increased transport and sedimentation of suspended material is called siltation and it is a major source of pollution in waterways in some parts of the world 7 8 High sedimentation rates can be a result of poor land management and a high frequency of flooding events If not managed properly it can be detrimental to fragile ecosystems on the receiving end such as coral reefs 9 Climate change also affects siltation rates 10 In estuarine environments settling can be influenced by the presence or absence of vegetation Trees such as mangroves are crucial to the attenuation of waves or currents promoting the settlement of suspended particles 11 Human enhanced sedimentation Edit This section is an excerpt from Sedimentation enhancing strategy edit Gediz delta showing a typical natural delta landscape Sedimentation enhancing strategies are environmental management projects aiming to restore and facilitate land building processes in deltas 12 Sediment availability and deposition are important because deltas naturally subside and therefore need sediment accumulation to maintain their elevation particularly considering increasing rates of sea level rise 13 14 Sedimentation enhancing strategies aim to increase sedimentation on the delta plain primarily by restoring the exchange of water and sediments between rivers and low lying delta plains Sedimentation enhancing strategies can be applied to encourage land elevation gain to offset sea level rise 15 Interest in sedimentation enhancing strategies has recently increased due to their ability to raise land elevation which is important for the long term sustainability of deltas 12 Chemistry EditIn chemistry sedimentation has been used to measure the size of large molecules macromolecule where the force of gravity is augmented with centrifugal force in an ultracentrifuge Sedimentation equilibrium EditMain article Sedimentation equilibrium When particles settling from a suspension reach a hard boundary the concentration of particles at the boundary is opposed by the diffusion of the particles The distribution of sediment near the boundary comes into sedimentation equilibrium Measurements of the distribution yields information on the nature of the particles 16 17 Classification EditClassification of sedimentation 18 Type 1 sedimentation is characterized by particles that settle discretely at a constant settling velocity or by the deposition of Iron Rich minerals to streamlines down to the point source They settle as individual particles and do not flocculate stick to each other during settling Example sand and grit material Type 2 sedimentation is characterized by particles that flocculate during sedimentation and because of this their size is constantly changing and therefore their settling velocity is changing Example alum or iron coagulation Type 3 sedimentation is also known as zone sedimentation In this process the particles are at a high concentration greater than 1000 mg L such that the particles tend to settle as a mass and a distinct clear zone and sludge zone are present Zone settling occurs in lime softening sedimentation active sludge sedimentation and sludge thickeners See also EditCoagulation disambiguation Notes Edit sedimentation Oxford English Dictionary Online ed Oxford University Press Subscription or participating institution membership required Jackson Julia A ed 1997 sedimentation Glossary of geology Fourth ed Alexandria Virginia American Geological Institute ISBN 0922152349 Jackson 1997 aggradation Jackson 1997 rate of sedimentation Paola C Voller V R 2005 A generalized Exner equation for sediment mass balance Journal of Geophysical Research 110 F04014 Bibcode 2005JGRF 11004014P doi 10 1029 2004JF000274 Blatt Harvey Middleton Gerard Murray Raymond 1980 Origin of sedimentary rocks 2d ed Englewood Cliffs N J Prentice Hall pp 30 31 122 123 ISBN 0136427103 Siltation amp Sedimentation blackwarriorriver org Archived from the original on 2009 12 21 Retrieved 2009 11 16 Siltation killed fish at Batang Rajang Digest on Malaysian News malaysiadigest blogspot com Retrieved 2009 11 16 Victor Steven Neth Leinson Golbuu Yimnang Wolanski Eric Richmond Robert H 2006 02 01 Sedimentation in mangroves and coral reefs in a wet tropical island Pohnpei Micronesia Estuarine Coastal and Shelf Science 66 3 4 409 416 Bibcode 2006ECSS 66 409V doi 10 1016 j ecss 2005 07 025 U D Kulkarni et al The International Journal of Climate Change Impacts and Responses Rate of Siltation in Wular Lake Jammu and Kashmir India with Special Emphasis on its Climate amp Tectonics The International Journal of Climate Change Impacts and Responses Retrieved 2009 11 16 Van Santen P Augustinus P G E F Janssen Stelder B M Quartel S Tri N H 2007 02 15 Sedimentation in an estuarine mangrove system Journal of Asian Earth Sciences Morphodynamics of the Red River Delta Vietnam 29 4 566 575 Bibcode 2007JAESc 29 566V doi 10 1016 j jseaes 2006 05 011 a b Nicholls R J Hutton C W Adger W N Hanson S E Rahman Md M Salehin M eds 2018 Ecosystem Services for Well Being in Deltas Integrated Assessment for Policy Analysis Cham Springer International Publishing doi 10 1007 978 3 319 71093 8 ISBN 978 3 319 71092 1 S2CID 135458360 Syvitski J P 2008 Deltas at risk Sustainability Science 3 1 23 32 doi 10 1007 s11625 008 0043 3 ISSN 1862 4065 S2CID 128976925 Giosan L Constantinescu S Filip F Deng B 2013 Maintenance of large deltas through channelization Nature vs humans in the Danube delta Anthropocene 1 35 45 doi 10 1016 j ancene 2013 09 001 Paola C Twilley R R Edmonds D A Kim W Mohrig D Parker G Viparelli E Voller V R 2011 Natural Processes in Delta Restoration Application to the Mississippi Delta Annual Review of Marine Science 3 1 67 91 Bibcode 2011ARMS 3 67P doi 10 1146 annurev marine 120709 142856 ISSN 1941 1405 PMID 21329199 The Nobel Prize in Physics 1926 NobelPrize org 27 Nov 2021 Retrieved 27 November 2021 Piazza Roberto Buzzaccaro Stefano Secchi Eleonora 2012 06 27 The unbearable heaviness of colloids facts surprises and puzzles in sedimentation Journal of Physics Condensed Matter 24 28 284109 Bibcode 2012JPCM 24B4109P doi 10 1088 0953 8984 24 28 284109 ISSN 0953 8984 PMID 22738878 S2CID 23309333 Coe H S Clevenger G H 1916 Methods for determining the capacities of slime settling tanks Transactions of the American Institute of Mining and Metallurgical Engineers 55 356 Retrieved from https en wikipedia org w index php title Sedimentation amp oldid 1131215440, wikipedia, wiki, book, books, library,
