Sandschicht

A sandschicht is a sedimentary layer dominated by sand, a granular material whose grain size typically ranges from about 0.06 to 2 millimeters. In sedimentary geology and soil science, sandschichten are common units that can occur alone or interlayered with finer or coarser sediments. They can be clean or interbedded with silt or clay and often display sorting and sedimentary structures such as cross-bedding or ripple marks.

Formation and properties: Sandschichten form through deposition in wind-blown (aeolian) dunes, river and shoreline environments, deltas, beaches, or shallow marine settings, as well as glaciofluvial outwash. They tend to be moderately to well sorted, have relatively high porosity and permeability, and can range from unconsolidated to cemented or lithified sandstones. Their thickness can vary from a few centimeters to several meters.

Significance: Because of high permeability, sandschichten commonly serve as aquifers or aquitards in groundwater systems. In civil engineering, their presence influences foundation design, settlement, and potential liquefaction during earthquakes. In archaeology and paleoenvironment studies, sand layers can act as stratigraphic markers and help constrain the timing of past events.

Investigation: Investigation combines drilling and coring, grain-size analysis, sedimentary structures interpretation, and geophysical methods such as seismic refraction or electrical resistivity. Dating methods include luminescence dating for sand deposits, or radiocarbon dating in associated organic layers.

See also: sandstone, sedimentology, stratigraphy, aquifer.