Alluvium (from the
Latin,
alluvius, from
alluere, "to wash against") is loose, unconsolidated (not cemented together into a solid
rock)
soil or
sediments, which has been
eroded, reshaped by water in some form, and redeposited in a non-
marine setting. Alluvium is typically made up of a variety of materials, including fine particles of
silt and
clay and larger particles of
sand and
gravel. When this loose alluvial material is deposited or cemented into a
lithological unit, or
lithified, it is called an
alluvial deposit.