Branko Music1 / Femke Martens2 / Jeroen Poblome2 / Peter Talloen2 / Marc Waelkens2
(1University of Ljublijana, Slovenia/ 2Catholic University of Leuven, Belgium)
Since 1990, a team directed by Marc Waelkens of the Catholic University of Leuven is conducting interdisciplinary research on the town and territory of ancient Sagalassos in Pisidia. After almost a decade of large-scale excavations in the town centre, however, nearly nothing was known on the spatial and chronological development of the wider urban area. Therefore, as part of a PhD by F. Martens on the urban development of the town, it was decided to initiate a programme of test soundings, excavated throughout the urban area from 1998 onwards, whereas simultaneously a programme of intensive archaeological survey was started in 1999, comprising the systematic collection of all archaeological surface evidence as well as the systematic recording of surface architecture. Important progress was made in the urban research, when from 2002 onwards also geophysical survey was applied at Sagalassos, which was carried out by a team supervised by B. Music from the department of Archaeology from Ljubljana University (Slovenia). The excellent results of this geophysical survey at Sagalassos, which was an all but obvious playground for geophysicists, show that even in such extremely difficult cases an integrated approach combining different research techniques and fields of expertise can lead to a better understanding of ancient urban landscapes. The research at Sagalassos has proven how the results of various prospection techniques can form complementary contributions to the construction of the visualization system framework. With respect to the applied geophysical techniques, magnetic prospection, which is a relatively fast and efficient technique to detect and map architectural remains, proved to provide the best results at Sagalassos. In the region of Sagalassos distinctive bipolarity of magnetic anomalies can be importantly decreased, so that the displacement of magnetic anomalies with regard to the element causing the anomaly can be significantly reduced by applying an OnPole transformation algorithm. Furthermore, 2D and 3D magnetic modelling based on the Earth’s magnetic field model (IGRF), allowed to calculate aspects such as the depth of the anomaly and its geometrical properties, whereas in the case of architectural elements even the type of building material could be determined. By comparing the measured magnetic anomalies and their sources with the excavated archaeological remains, step by step reliable magnetic models were developed. In addition, small-scale resistivity, conductivity and magnetic susceptibility surveys were carried out, so that geophysically independant data sources were derived, which allowed to estimate the parameters required for a reliable visualization of the data. As a next step in the process of the 3D representation of architectural remains at Sagalassos, now also ground penetrating georadar will be used. Archaeologically, the results of the geophysical survey have proven extremely useful to reconstruct the concept and the spatial organization of the urban plan. In a non-destructive and time-efficient manner a wide view upon the town planning outside the excavated monumental centre is obtained. By using this spatial information, expensive and destructive large-scale excavations can be better planned or can be replaced by small test soundings, carried out at well-selected spots, where particular questions concerning chronology of the layout or the functional use of an area can be answered. As such, currently the chronological development of the urban plan of the eastern residential area of Sagalassos is being studied through test soundings upon the network of streets and using the results of the geophysical survey in combination with the mapped surface architecture. In a second stage, georadar will be used to determine which street surfaces were still paved -and thus in use- during the final phases of the occupation of the town. In addition, this technique will also be used to trace water channels underlying the streets, as part of a research on the organization and chronological development of the urban water network.