Earthen mounds in the Glubczyce Forest (SW Poland) - are they prehistoric long-barrows? Geoarchaeology of the Silesian soil record and human-environment interplay in the Holocene

Two earthen mounds, trapezoid in shape, oriented along the W-E/NW-SE axis and located in prominent landscape positions, were recently discovered in the Glubczyce Forest in the loess area of the Glubczyce Plateau (SW Poland). Their resemblance to long-barrows of the Funnel Beaker culture, as yet unknown in this part of Silesia prompted low-invasive research, involving ALS data analysis, magnetic prospection and a study of soil properties. The objective was to determine if these are indeed anthropogenic structures and if so, how and when were they built. The results indicate: 1) a transformation from chernozemic (Phaeozem) to clay-illuvial soil (Luvisol/Retisol) in the Glubczyce Forest area. Similar processes were identified in neighbouring Central European loess regions and linked with prehistoric climate/vegetation changes (the spread of dense, beech-dominant forests). Human management of the landscape (involving sustained deforestation), enabled the patchy preservation of chernozemic soils until the present-day, 2) both mounds are anthropogenic features, built on a Phaeozem using chernozemic soil. Their construction occurred before the soil transformation, i.e. most likely in prehistory. The development of the Glubczyce Forest may have taken place during the Migration period - a time of settlement decline in Silesia, and 3) the Glubczyce Forest bears further traces of anthropogenic activity: ancient agriculture (field systems), funerary practices, forest management and WWII combat.