alluvial-fan
/ˌæljʊˈviː.əl fæn/ IELTSAcademic
noun
A fan-shaped area of sand, gravel, and soil spread by water where a fast river slows down and drops its load. It often forms at the foot of mountains or hills.
- The village sits on an alluvial fan.
- Floodwater spread across the alluvial fan.
- Farmers use the alluvial fan for grazing.
Adinary Nuance
An alluvial fan is not the same as a delta or an avalanche deposit. A delta forms where a river meets a lake or sea; an alluvial fan forms on land, usually at a mountain front. It is also broader than a simple sediment pile, because the shape spreads out like a fan.
In other languages
- Vietnamese
- quạt phù sa
- Spanish
- abanico aluvial
- Chinese
- 冲积扇
- Japanese
- 扇状地
- Korean
- 선상지
Etymology
Alluvial comes from Latin alluvius, from alluere meaning “to wash against.” Fan describes the broad, spreading shape. The term has been used in geology since the 19th century.
Common phrases
alluvial fan depositactive alluvial fanformed on an alluvial fan
Synonyms
Related words
Frequently asked questions
- Is an alluvial fan the same as a delta?
- No. A delta forms where a river enters standing water. An alluvial fan forms on dry land at the base of a slope.
- Is alluvial fan used in geology?
- Yes. It is a common geology term, especially in river and landform studies.
- How do I use alluvial fan in a sentence?
- You can say, “The town is built on an alluvial fan.”
- Is alluvial fan a common everyday word?
- No. It is mostly used in geography, geology, and academic writing.