alluvial fan

All Sources -
Updated Media sources (1) About encyclopedia.com content Print Topic Share Topic
views updated

alluvial fan Fan-shaped area of alluvium (water-borne sediment) deposited by a river when the stream reaches a plain on lower ground, and the water velocity is abruptly reduced. Organic matter is also transported, making the soil highly fertile. Valuable minerals such as cassiterite (tin ore, SnO2), diamonds, gold, and platinum are often found in alluvial fans.

World Encyclopedia
views updated

alluvial fan(alluvial cone) A mass of sediment deposited at some point along a stream course at which there is a sharp decrease in gradient (e.g. between a mountain range and a plain). Essentially, a fan is the terrestrial equivalent of a river-delta formation.

A Dictionary of Ecology MICHAEL ALLABY
views updated

alluvial fan (alluvial cone) Mass of sediment deposited at some point along a stream course at which there is a sharp decrease in gradient, e.g. between a mountain range and a plain. Essentially, a fan is the terrestrial equivalent of a river-delta formation.

A Dictionary of Earth Sciences AILSA ALLABY and MICHAEL ALLABY
views updated

alluvial fan A mass of sediment deposited at some point at which there is a sharp decrease in gradient, e.g. between a mountain range and a plain. Essentially, a fan is the land-bound equivalent of a river-delta formation.

A Dictionary of Plant Sciences MICHAEL ALLABY