Alluvium Alluvium Alluvium (from the Latin "alluvius", from "alluere", "to wash against") is loose, unconsolidated (not cemented together into a solid rock) soil or sediment that 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. The term "alluvium" is not typically used in situations where the formation of the sediment
Eluvium 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. Eluvium 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 or leaching. 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