a fan-shaped alluvial deposit formed by a stream where its velocity is abruptly decreased, as at the mouth of a ravine or at the foot of a mountain.
a fan-shaped accumulation of silt, sand, gravel, and boulders deposited by fast-flowing mountain rivers when they reach flatter land
A fan-shaped mass of sediment, especially silt, sand, gravel, and boulders, deposited by a river when its flow is suddenly slowed. Alluvial fans typically form where a river pours out from a steep valley through mountains onto a flat plain. Unlike deltas, they are not deposited into a body of standing water.
- Alluvial fan
a fan-shaped alluvial deposit formed by a stream where its velocity is abruptly decreased, as at the mouth of a ravine or at the foot of a mountain. Historical Examples Steep valleys descend from the higher country to join the main valley and at the mouth of every tributary is an alluvial fan. The Andes […]
- Alluvial mining
noun a method of extracting minerals by dredging alluvial deposits Historical Examples Several of the alluvial mining companies are getting gold in increased quantities. A Boy’s Voyage Round the World The Son of Samuel Smiles
- Alluvial plain
a level or gently sloping surface formed of sediments laid down by streams, generally during flooding. Historical Examples Perhaps it is the nature of that alluvial plain that accounts also for so plentiful a harvest of mosquitoes. The Fortunate Isles Mary Stuart Boyd The stones at Beled had been the first signs that we were […]
Law. a gradual increase of land on a shore or a river bank by the action of water, whether from natural or artificial causes. overflow; flood. Now Rare. . Historical Examples alluvion is the name for an accession of land washed up on the sea-shore or on a river-bank by the waters. International Law. A […]