Kelderlaag

Kelderlaag is a Dutch term used in geology and archaeology to describe the lowest deposit or stratigraphic unit encountered at a site, roughly corresponding to the basement layer of the local stratigraphy. The word literally means "cellar layer" and reflects its position beneath younger sediments or fills.

In excavation reports and field descriptions, the kelderlaag is recorded as the base context for a trench or site. It may be composed of compact clay, silt, or bedrock, and can be a paleosol, a basal alluvial layer, or weathered parent material. Because it is beneath the more recent accumulations, it often contains older artifacts, fauna, or environmental indicators that help interpret the site's chronology and past environments. Preservation varies with burial conditions; it may be relatively well-preserved or heavily altered by water, roots, or human activity.

In stratigraphic terms, the kelderlaag is not an official international unit but a practical label used by Dutch researchers to denote the bottom-most identifiable layer. It is typically distinguished from overlying layers by color, texture, inclusions, or stratigraphic contacts; dating methods such as radiocarbon or optically stimulated luminescence may be applied to materials found within or above it.

Regional usage centers on the Netherlands and Flanders, where many archaeological and geomorphological records discuss a kelderlaag as the basal context of a trench. See also terms: stratigraphy, bedrock, paleolandscape, archaeological layer.