Alluvium is soil land deposited by a river or other running water. The structure formed is called an alluvial deposit. Glaciers may also deposit alluvium, see glacial till. For the heavy metal band see Soil (band) Soil is a general term for the material that lies on the surface of the earth, supporting the growth of plants and serving as a habitat for animal life from microrganisms to small animals. ... An alluvial deposit is an accumulation of alluvium (sediment), sometimes containing valuable ore and gemstones, or simply consisting of gravel, sand, or clay, in the bed or former bed of a river. ... Categories: Geology stubs | Glaciology | Sedimentary rocks ...

A river is continually picking up and dropping solid particles of rock and dirt 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. Flood Plain along Lynches River Johnsonville, South Carolina Showing high water mark on tupelo and cypress trees In geography, a flood plain is a plain formed of sediment, typically dropped by a river. ...

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. Flood Plain along Lynches River Johnsonville, South Carolina Showing high water mark on tupelo and cypress trees In geography, a flood plain is a plain formed of sediment, typically dropped by a river. ... Nile River delta, as seen from Earth orbit. ...

Alluvium is typically made up of a variety of materials. The finer material, or silt, consists of sand and mud. Larger particles, or gravel, are also typically present in a wide range of sizes. Silt refers to soil or rock particles of a certain very small size range (see grain size). ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... In computer gaming, a MUD (multi-user dungeon, dimension, or sometimes domain) is a multi-player computer game that combines elements of role-playing games, hack and slash style computer games, and social Internet Relay Chat channels. ... Gravel Gravel is rock that is of a certain size range. ...

The amount of solid 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 Missouri 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, the Huang He 796 million tons, and the Po River in Italy 67 million tons. For other Yellow Rivers, see Yellow River (disambiguation). ... The Missouri River and its tributaries N.P. Dodge Park, Omaha, Nebraska High silt content makes the Missouri (left) noticably lighter than the Mississipi here at their confluence above St. ... Length 6,270 km Elevation of the source 450 m Average discharge Saint Louis¹: 5,500 m³/s Vicksburg²: 16,800 m³/s Baton Rouge³: 12,800 m³/s Area watershed 2,980,000 km² Origin Lake Itasca Mouth Gulf of Mexico Basin countries United States (98. ... For other Yellow Rivers, see Yellow River (disambiguation). ... The Po river The Po River (Padus in ancient times) flows 652 kilometers from west to east across northern Italy, from Mount Monviso (in the Cottian Alps) to the Adriatic Sea near Venice. ...

Alluvial deposits often contain valuable ores such as gold and platinum and a wide variety of gemstones. An alluvial deposit is an accumulation of alluvium (sediment), sometimes containing valuable ore and gemstones, or simply consisting of gravel, sand, or clay, in the bed or former bed of a river. ... General Name, Symbol, Number gold, Au, 79 Chemical series transition metals Group, Period, Block 11, 6, d Appearance metallic yellow Atomic mass 196. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Atomic mass 195. ... A gemstone is a mineral, rock (as in lapis lazuli) or petrified material that when cut or faceted and polished is collectible or can be used in jewellery. ...

Throughout history many shallow lakes have been filled in with alluvium, leaving fertile plains. Alluvial soils are almost always 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. The Nile in Egypt Length 6 695 km Elevation of the source 1 134 m Average discharge 2 830 m³/s Area watershed 3 400 000 km² Origin Africa Mouth the Mediterranean Basin countries Uganda - Sudan - Egypt The Nile (Arabic: النيل an-nÄ«l), in Africa, is one of the two... (5th millennium BC – 4th millennium BC – 3rd millennium BC - other millennia) // Events City of Ur in Mesopotamia (40th century BC). ...

See also

• Alluvial plain
• Alluvial fan