f Combined Geoelectrical and GPR Investigations of the neolithic archealogical settlement “Plocnik”- Serbia

The archaeological Neolithic settlement “Plocnik” is situated in central Serbia, near the town of Prokuplje, covering a huge area of about 80 hectares and belonging to the well known culture of “Vinca”. Earlier archeological investigations, conducted in the classical manner by making archeological trenches at several sites, relieved the existence of the large settlement and even more important fact of the possible metallurgy activities. The findings of the various copper tools and jewellery together with copper ores and minerals (chalchopyrite, malachite) are related with the clearly exposed conical and cylindrical pits in the open profile at the vertical cliff, with the diameters up to 9 meters and 3.5-4 meters deep. These pits are filled with the layers of the ash probably as a consequence of the copper production. There are also smaller and shallower pits (with diameters up to 3 meters and 1.5-3 meters deep) filled mostly with the animal bones, fragments of pottery and anthropomorphic terracotta. The simple geological structure, consisting of almost homogenous loess-like, four to five meters thick clayey layer, which covers the alluvial pebble of the Toplica river, is evident from the vertical cliff created by the river flow. This fact greatly improves the possibility of successful application of the geophysical methods by reducing the geological interference in delineating anomalies caused by archeological remainders. Considering the dimensions of the possible targets, their depths of burial and possible contrast of their physical properties to surrounding material, it was decided to apply geoelectrical mapping in order to detect relatively large pits filled with the ash. The apparent resistivity map (Fig.1) thus obtained, served to position the profiles of the electrical scanning method for the detailed inspection of the most interesting zones and for the further 2D interpretation of the apparent resistivity pseudosections. It revealed the existence of the two markedly different resistivity zones, separated by the steeply dipping boundary. The contact between the lower resistivity zone (55-65 Ohmm) and higher resistivity material (up to 150 Ohmm) is basically two-dimensional. Inside the high resistivity zone three closed anomalies are indicated suggesting the presence of the 3D structures. In order to further investigate the contact between the two zones, as well as to get the information about depth extent and shape of the structures causing 3D anomalies, the electrical scanning technique with 26 equispaced electrodes (two meters apart) was employed. The surveying along three parallel profiles (Fig.1), set perpendicularly to 2D contact was performed at five depth levels.