Główne etapy zasiedlenia i rozbudowy grodziska w Bonikowie (Wielkopolska) w świetle badań litologicznych i geochemicznych

The early medieval fortified settlement in Bonikowo was located within the wetland, in very marshy backwaters of the middle Obra river (the Obra Marshy Meadows). The Bonikowo stronghold belonged to a system of numerous small castles of southern Great Poland which had been formed in the period before the rise of the centralized state. This was a concave fortified settlement, consisting of many parts, with three ramparts, originating in different phases of the Middle Ages, as was confirmed by dating of archaeological pottery findings and by absolute dating. The castle was built with material from the sandy sediment of the Obra river backwaters. Geochemical analysis shows the length and intensity of the settlement and economic use of internal zones of the ramparts, especially of the internal zones within the rampart II, considered the oldest.