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Eluvium. In geology, eluvium or eluvial deposits are geological deposits and soils that are derived by in situ weathering or weathering plus gravitational movement or accumulation. The process of removal of materials from geological or soil horizons is called eluviation or leaching. There is a difference in the usage of this term in geology and ...
An alluvial plain is a plain (an essentially flat landform) created by the deposition of sediment over a long period by one or more rivers coming from highland regions, from which alluvial soil forms. A floodplain is part of the process, being the smaller area over which the rivers flood at a particular time. In contrast, the alluvial plain is ...
Alluvium (from Latin alluvius, from alluere 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. [1][2][3] Alluvium is also sometimes called alluvial deposit. [4][5] Alluvium is typically geologically young and is ...
Placer deposit. Heavy minerals (black) forming placers along ripple marks. In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. [1] The name is from the Spanish word placer, meaning " alluvial sand".
Placer mining. 19th-century miner pouring water into a rocker box which, when rocked back and forth, will help separate gold dust from the alluvium. Placer mining (/ ˈplæsər /) [1] is the mining of stream bed deposits for minerals. [2] This may be done by open-pit mining or by various surface excavating equipment or tunneling equipment.
Fluvial sediment processes. Deep, eroding glaciofluvial deposits alongside the Matanuska River, Alaska. In geography and geology, fluvial sediment processes or fluvial sediment transport are associated with rivers and streams and the deposits and landforms created by sediments. It can result in the formation of ripples and dunes, in fractal ...
An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but are also found in more humid environments subject to intense rainfall and in areas of modern glaciation.
An alluvial river is one in which the bed and banks are made up of mobile sediment and/or soil. Alluvial rivers are self-formed, meaning that their channels are shaped by the magnitude and frequency of the floods that they experience, and the ability of these floods to erode, deposit, and transport sediment. For this reason, alluvial rivers can ...