Alluvial Fan

(redirected from Alluvial fans)
Also found in: Dictionary, Thesaurus.

alluvial fan

[ə′lüv·ē·əl ′fan]
A fan-shaped deposit formed by a stream either where it issues from a narrow moutain valley onto a plain or broad valley, or where a tributary stream joins a main stream.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Alluvial Fan


a type of relief in the form of a slightly convex fan, formed through the accumulation of loose detrital material in the estuarine part of temporary streams and small rivers where they emerge from mountains onto piedmont plains or from gorges onto broader valleys. It forms as the result of the deposition of material suspended in water when the speed of the current of water decreases owing to a change in gradient. Populated areas are frequently situated on alluvial fans.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The cross section begins at the top of the Nuomuhong alluvial fan in the south and extends to the Amunike Mountain piedmont in the north.
Within the walls of Acopios 1 and Acopios 2 a high angle (subvertical), south-dipping fault zone affecting alluvial fan deposits can be seen (Figs.
Low scores for this factor were also found on alluvial fans that have drainages confined to the metamorphic portions of the Sierra Foothills such as the Calaveras River fan, which tend to have fine textured sediments compared to fans sourced in granitic terrain in the high Sierra Nevada.
The Santa Lucia Highlands AVA has a great reputation for Pinot Noir, and growers there continue to fine tune clones, rootstocks and trellis systems to improve wine quality and a sense of the unique terroir on alluvial fans and escarpments located on the west side of the Salinas Valley.
If we look more broadly in Gale Crater, we can see that there is a prominent feature that geologists call an alluvial fan.
Three alluvial fans within the plain; namely: the Zarub fan in the north, the Moundassah fan in the middle and the Ajran fan in the south (Al-Shamsei, 1993).
Accumulation processes have a lower manifestation, especially, in creeks confluence area with the Valsan river mouth and its tributaries valleys as alluvial fan. Slope processes are the following: gullying, torrentiality and run-off.
The alluvial sediments and the alluvial fans rainfall water enters the aquifer have a considerable spread.
indicate the existence of complex processes of change in the landscape of the Pantanal, resulting from the sedimentary dynamic in alluvial fans. In these fan regions the landscape changes continuously because of sedimentation and by avulsion processes.