Temporal variation of prehistoric human settlement recorded in the oxbow lake deposits of San river (Sandomierz Basin, SE Poland)

This study presents the sedimentological and pollen analysis, and radiocarbon dating of the palaeochannel fill deposits situated on the wide alluvial ridge on which 131 archaeological sites were discovered. The analyzed territory covers the right bank of the San river valley (in the area of the Leszno profile) with an area of 72.5 km². Increase of fine-grain sand sediments, and the presence of redeposited fragments of clayey silts (soil aggregates) correlates well with the increase man’s activity in the 2^nd and the 1^st half of the 1 ^st millennia BC (the decline of the Mierzanowice culture, the Trzciniec culture, the Tarnobrzeg Lusatian culture) as well as in the 1^st millennium AD (the Przeworsk culture and the early Medieval settlement) and with transformation of plant communities recorded in the palynological sequence. The layer of sediments at the depth of 85–69 cm with the highest proportion of the finest clay fraction may indicate the reduction of cultivation or abandonment of arable land (the pre-Roman (La Tène) period).