Eluvium

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Related to Eluvial deposit: Eluvial horizon

eluvium

[ē′lü·vē·əm]
(geology)
Disintegrated rock material formed and accumulated in situ or moved by the wind alone.

Eluvium

 

loose deposits that occur when the original (parent) rock weathers at its place of origin. The eluvium comprises weathering crusts and soils.

A distinction is made between the orthoeluvium of crystalline (magmatic and metamorphic) rocks, the metaeluvium of consolidated sedimentary rocks, and the neoeluvium of young, unconsolidated deposits (in the last two cases, the parent rocks consist largely of redeposited and slightly altered products of weathering). The most characteristic type is orthoeluvium, which ranges in composition from pebbles and boulders in cold climates to clays in hot, humid climates. On the basis of degree of decomposition, a distinction is made between siallitic eluvium, in which the original aluminosilicates are preserved; acidic siallitic eluvium, which is composed chiefly of newly formed hydrous aluminosilicates of the group of clay minerals; and allitic, or ferralitic, eluvium, in which a significant share of the silicates have decomposed and are represented by free hydroxides of aluminum and iron.

E. V. SHANTSER

References in periodicals archive ?
In other words, any potential feed for the plant is likely to be from eluvial deposits located within strong geochemical anomalies.
The project provided a stimulating challenge for 'genetic' and 'exploration target' modelling of an unusual group of alluvial and eluvial deposits.
3) Eluvium or eluvial deposits are those geological deposits and soils that are derived by in situ weathering or weathering plus gravitational movement or accumulation.
In March 2001 Lees began mining the eluvial deposits downhill from the veined blue schist body, and approximately 2,000 cubic yards were processed through a jig system.
In late 2003, Lees began stripping off overburden in an attempt to uncover the in situ source of the eluvial deposits.
Gold has been obtained from alluvial and eluvial deposits in the YaourC region for centuries; the region had attracted European prospectors from the early part of the 20th century until the outbreak of the Second World War in 1939.
Now that it has gained its formal independence after something like thirty years of struggle, the numerous primary gold showings there may also hide some economic eluvial deposits.
These are best described as those having really dry deserts with rainfall of less than 250 mm/y within which there are either known alluvial or eluvial deposits of precious metals, or geological provinces having the appropriate potential for finding such deposits.
This adds to the existing production from Adola Gold Mines which is working alluvial, colluvial, and eluvial deposits.