The myth of ‘Bohunician soil’: A re-evaluation of the MIS 3 palaeosol record at the Brno-Bohunice site (Czechia)

Abstract

Several important loess sections containing marine isotope stage 3 palaeosols have been discovered in the area of the Bohunice district of the city of Brno. Most of them were previously examined mainly from an archaeological point of view in relation to the Middle/Upper Palaeolithic transition, and their palaeopedological records were not studied in detail. The term ‘Bohunician soil’ was introduced during the initial archaeological research of the Brno-Bohunice site and has since been used to refer to palaeosols containing Bohunician artefacts in the surrounding region without any clear definition of what the term actually means. A newly exposed loess section (Brno-Bohunice 2018) and a preserved section from the last archaeological research (Brno-Bohunice 2002) provide an opportunity to revise the Brno-Bohunice palaeosol record and to assess the reasonability of the term ‘Bohunician soil’. We present a comprehensive multiproxy evaluation of soil development over the period of 60–30 ka BP, based on a combination of soil micromorphology and physical and geochemical proxies. The oldest recorded soil horizon was identified below the originally recognized ‘Lower palaeosol’ in the 2002 section whereas in the 2018 section the oldest horizon is of colluvial origin. We newly classify the ‘Lower palaeosol’ as a Cambisol and Tundra gley and interpret the ‘Upper palaeosol’ as a Regosol. Our new division and reassessment of dating results shows that the majority of the Bohunician artefacts found mostly at the transition between the Cambisol and Tundra gley were not in their original stratigraphic position. They were probably lifted by freezing-thawing processes from an earlier position between the soliflucted soil horizon and the Cambisol. It is likely that even in the first excavated contexts of so-called Bohunician soil, artefacts were not necessarily found in their original position. The term therefore appears to have no relevance.