Alluvium


Alluvium

Alluvium (from the Latin, "alluvius", from "alluere", "to wash against") is soil or sediments deposited by a river or other running water. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel.

Flowing water associated with glaciers may also deposit alluvium, but deposits directly from ice are not alluvium (see glacial till).

A river is continually picking up and dropping solid particles of rock and soil from its bed throughout its length. Where the river flow is fast, more particles are picked up than dropped. Where the river flow is slow, more particles are dropped than picked up. Areas where more particles are dropped are called alluvial or flood plains, and the dropped particles are called alluvium.

Even small streams make alluvial deposits, but it is in the flood plains and deltas of large rivers that large, geologically-significant alluvial deposits are found.

The amount of matter carried by a large river is enormous. The names of many rivers derive from the color that the transported matter gives the water. For example, the Huang He in China is literally translated "Yellow River", and the Mississippi River in the United States is also called Big Muddy. It has been estimated that the Mississippi River annually carries 406 million tons of sediment to the sea [cite book | last = Mathur | first = Anuradha | coauthors = Dilip da Cunha | title = Mississippi Floods: Designing a Shifting Landscape | publisher = Yale University Press | date = 2001 | location = New Haven, CT | isbn = 0-300-08430-7] , the Huang He 796 million tons, and the Po River in Italy 67 million tons [cite book | last = Dill | first = William A. | title = Inland fisheries of Europe | url = http://www.fao.org/docrep/009/t0377e/t0377e00.htm | publisher = UN Food and Agriculture Organization | date = 1990 | location = Rome, Italy | isbn = 92-5-102999-7] .

Alluvium often contains valuable ores such as gold and platinum and a wide variety of gemstones. Such concentrations of valuable ores is termed a placer deposit.

Throughout history, many shallow lakes have been filled in with alluvium to leave fertile plains (alluvial soils are often very fertile). The alluvial mud annually deposited by the Nile has enabled the Egyptians to grow crops since at least the 4th millennium BC without artificial fertilization.

Since the construction of the Aswan Dam on The Nile in Egypt, 95% of the alluvium deposits at the mouth of the Nubia-Nasser Lake are gone, thus depriving the Nile delta of its fertility. Since 1964, 3.8 billion cubic meters of sediments have deposited in this man-made lake. Proposals have been made to dredge this alluvium and pump it in slurry pipelines to shore where it can be used to fertilize the desert. [ABULNAGA Baha - EL-SAMMANY Moustafa " Mine Over Water" International water power & dam construction (Int. water power dam constr.) ISSN 0306-400X CODEN IWPCDM International water power and dam construction - 2003, vol. 55, no11, pp. 22-26 ]

References

*"Dennis Garrett", [http://www.alaskafreegold.com Blue Ribbon Mine, Alaska]

ee also

*Alluvial desert
*Alluvial fan
*Alluvial plain
*Alluvion
*Colluvium
*Eluvium
*Fluvial
*Illuvium


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  • Alluvium — oder Alluvion bedeutet wörtlich Anschwemmung. Da sich die geologische Tätigkeit der Gegenwart im Binnenland meist als Anschwemmung äußert, wurde der Begriff »Alluvium« als ein Zeitbegriff in die Geologie eingeführt und mit ihm die in… …   Lexikon der gesamten Technik

  • alluvium — (n.) matter deposited by flowing water, 1660s, from M.L. alluvium, neuter of alluvius washed against, from L. alluere wash against, from ad to, against (see AD (Cf. ad )) + luere, comb. form of lavere to wash (see LAVE (Cf …   Etymology dictionary

  • Alluvium — Al*lu vi*um, n.; pl. E. {Alluviums}, L. {Alluvia}. [L., neut. of alluvius. See {Alluvious}.] (Geol.) Deposits of earth, sand, gravel, and other transported matter, made by rivers, floods, or other causes, upon land not permanently submerged… …   The Collaborative International Dictionary of English

  • Alluvĭum — (Alluvialgebilde, Recente Formation), alle Gesteinsbildungen, welche unter Mitwirkung von Wasser erst in historischer Zeit, also seit etwa 6000 Jahren erfolgt sind, u. die noch jetzt an der Erdoberfläche entstehen. Am besten wird diese Periode… …   Pierer's Universal-Lexikon

  • Allūvium — (lat., »angeschwemmtes Land«, Alluvionen, Alluvialbildungen, rezente Bildungen), der Inbegriff aller Produkte der geologischen Gegenwart, der Alluvialperiode. Neben den Quellabsätzen, den an Bäche, Flüsse, Seen und Meere gebundenen Absätzen, den… …   Meyers Großes Konversations-Lexikon

  • Alluvium — Alluvĭum (lat.), Alluviālbildungen, Alluviōnen, durch Wasser oder Wind abgelagerte Gesteinsgebilde der Gegenwart (rezente Ablagerungen), so Flußanschwemmungen, Deltabildungen, Dünen, Sandbänke, Ablagerungen im Meere bis zum Tiefseeschlamm, Torf,… …   Kleines Konversations-Lexikon

  • Alluvium — oder postdiluvianisches Gebilde, ist die jüngste Formation der Erdrinde, wie sie sich täglich noch vor unsern Augen bildet. Es gehört hieher die Verwitterung der Felsen und Gesteine, wodurch die Ackererde gebildet wird, die Torfbildung,… …   Herders Conversations-Lexikon

  • alluvium — n. The land created by alluvion. Webster s New World Law Dictionary. Susan Ellis Wild. 2000 …   Law dictionary

  • Alluvium — Alluvium, Holozän, Nacheiszeit ⇒ Quartär …   Deutsch wörterbuch der biologie

  • alluvium — ► NOUN ▪ a fertile deposit of clay, silt, and sand left by river flood water. DERIVATIVES alluvial adjective. ORIGIN Latin, from luere to wash …   English terms dictionary


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