Review of illuvial bands origin; what might the presence of dark brown bands in sandy infillings of archaeological features or cultural layers mean?

Abstract

The presence of lamellae (or bands) often promises an interesting sedimentary archive related to the occupation or abandonment history of a site. How exactly might such types of bands be interpreted, and how do their presence change the original primary features preserved within the archaeological structure? For this review, two archaeological sites are introduced, both distinct in many aspects, located in different climatic regions, but with the presence of bands preserved inside of the infill, as well as in the locality’s background. One site is related to the Magdalenian/Epigravettian occupation in south-western Poland, and the second related to the Neolithic occupation in central Bohemia. What connect these two localities are their permeable sandy background, presence of human occupation, and the development of the above-described textural features. Sedimentological observations supported by micromorphology and geochemistry, as well as by magnetic susceptibility, revealed that, in both localities, the presence of dark brown bands was the result of repeated illuviation due to a kind of podsolization process not necessarily related to human presence. The illuvial lamellae/bands at the Kly site probably originated during the Subboreal due to the increased humidity connected with the presence of the disturbed background of the infill in the ditch. The Sowin site displays, at the very least, two phases of origin. One of the phases is pre-dated by glacial conditions, and the second is of late glacial or Holocene origin. The origin of these features in both study sites is due to precipitated water and the movement of clay down the section, but under their different conditions.