Aluskihiga

Aluskihiga is a term used in Estonian geology and soil science to describe a deposit or material that contains a basal sublayer. The word derives from alus, meaning base or foundation, and kiht, meaning layer, with the suffix -iga forming a modifier that conveys “with a sublayer” or “having a base layer.” In stratigraphic descriptions, aluskihiga indicates that beneath the principal stratigraphy there is a clearly identifiable sublayer of different lithology or grain size, such as a clay-rich base beneath sands or a compact horizon under loess.

In practice, the term helps distinguish materials with a notable basal interval from more uniform layers. It is used across geology, pedology (soil science), archaeology, and hydrogeology to denote how the sublayer affects interpretation of the sequence, soil properties, or groundwater flow. Descriptions often pair aluskihiga with the host material, for example in notes like “aluskihigaga savi” to indicate a clay that contains a basal sublayer, or “aluskihigiga kihid” to refer to horizons with a basal basal layer.

See also: stratigraphy, soil horizons, subsoil, sedimentology.

Note: The term is primarily found in Estonian-language sources and may be less common in English-language literature. As a linguistic formation, it illustrates how Estonian substrate-layer terminology is used to specify basal stratigraphic features.