Everything about Eluvium totally explained
» For the musician, see Eluvium (musician)In
geology,
eluvium or
eluvial deposits are those geological deposits and
soils that are derived by
in situ weathering or weathering plus gravitational movement or accumulation.
The process of removal of materials from geological or soil horizons is called
eluviation. There is a difference in the usage of this term in geology and
soil science. In soil science, eluviation is the transport of soil material from upper layers of soil to lower levels by downward precipitation of water across
soil horizons, and accumulation of this material (
illuvial deposit) in lower levels is called
illuviation. In geology, the removed material is irrelevant, and the deposit (eluvial deposit) is the remaining material.
Eluvial
ore deposits are those such as
tungsten and
gold placer deposits formed by settling and enriched by the winnowing or removal of lower density materials.
Diamonds within
yellow ground (weathered portions of
kimberlites) may be considered to be eluvial deposits.
Cassiterite and
columbite-tantalite deposits also occur as residual or eluvial concentrations. The Pitinga tin deposit in
Brazil, an eluvial deposit, is one of the largest tin mines in the world. Weathering
supergene enrichment of an
apatite rich
carbonatite in
Ontario has produced a significant eluvial
phosphate ore deposit.
