Eluvium

(redirected from Eluvial deposit)
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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 ?
The second sample was located in the southern part of the eluvial deposit in "bedrock clay" where a BRGM sample of 10 liters had yielded four diamonds between 1 millimeter and a quarter of a millimeter in size.
The sampling program was designed to test eluvial deposits composed of weathered bedrock that have been worked in the past and processed in a simple gravity processing plant located some 3 kilometres from the sample area.
There are also real opportunities for outlining additional eluvial deposits within the southwest extension area.
test for eluvial deposits of rare metals being eroded from a weakly