Alluvium
Alluvium (from
Floodplain alluvium can be highly fertile, and supported some of the earliest human civilizations.[6]
Definitions
The present
By the 19th century, the term had come to mean recent sediments deposited by rivers on top of older
Alluvium and diluvium were grouped together as colluvium in the late 19th century. "Colluvium" is now generally understood to mean sediments produced by gravity-driven transport on steep slopes, while the definition of "alluvium" has switched back to an emphasis on sediments deposited by river action. There continues to be disagreement over what other sediment deposits should be included under the term "alluvium."[8]
Age
Most alluvium is Quaternary in age and is often referred to as "cover" because these sediments obscure the underlying bedrock. Most sedimentary material that fills a basin ("basin fill") that is not lithified is typically lumped together as "alluvial".[9] Alluvium of Pliocene age occurs, for example, in parts of Idaho.[10] Alluvium of late Miocene age occurs, for example, in the valley of the San Joaquin River, California.[11]
See also
- Alluvial plain
- Bay mud
- Braided stream
- Desert pavement
- Eluvium
- Hydraulic action
- Illuvium
References
- ^ ISBN 0922152349.
- ^ Glossary of Geological Terms. Geotech.org. Retrieved on 2012-02-12.
- ^ Geology Dictionary – Alluvial, Aquiclude, Arkose. Geology.Com. Retrieved on 2012-02-12.
- ISBN 0922152349.
- ISBN 9780199653065.
- S2CID 140587757.
- ^ Allaby 2013, "alluvial".
- ^ .
- ^ Chisholm, Hugh, ed. (1911). . Encyclopædia Britannica (11th ed.). Cambridge University Press.
- ^ Ames, Dan (1998), "Formation of the Soils" (PDF), Soil Survey of Jerome County and Part of Twin Falls County, Idaho, Natural Resources Conservation Service, United States Department of Agriculture, p. 238
- USGS. p. 13.
External links
- Media related to Alluvium at Wikimedia Commons