PRELIMINARY RESULTS OF THE GEOPHYSICAL SURVEYS OF THE NETWORK OF DEFENCE SETTLEMENTS FROM THE BRONZE AGE BETWEEN THE BIEBRZA AND NAREW (NE POLAND)

This paper presents the results of geophysical research (geomagnetic and GPR) and preliminary hypotheses concerning "Valley Forts" type settlements in the cultural landscape of the Biebrza-Narew river valleys, in the Bronze Age, which were developed on the base of the results of geophysical research of selected sites. Non-invasive identification of this type of sites was carried out using the magnetometric prospecting method. Two sites in the Biebrza river valley (Jatwieź Duża) and Narew river valleys were selected. The map of distribution of magnetic anomalies allowed to outline the organization and structure of sediments in the horizontal dimension. Magnetometric images of the sites show a complicated arrangement of objects. A number of types of anomalies have been registered, out of which those describing the defensive character of fortified settlements point to stone and earth structures. At least two lines of fortifications have been registered for all the stands, manifesting themselves as linear groupings of anomalies, thus contradicting any possible cavities in the type of ditch or moat. In addition, the distribution of the anomalies indicates the existence of clear gaps in the fortification lines, which can be interpreted as entrances to the settlement or gateways. These objects clearly indicate the anthropogenic character or adaptation of this place for defensive purposes in the form of terracing and strengthening of slopes. This is indicated by multiple anomalies, which form concentric assumptions of the palisade/wooden and stone embankment type or their combinations.