Fluxgate, Overhouser And Caesium-Magnetometry For Archaeological Prospection At Roselle-Aiali (Italy)

The place name Aiali is sited on lowland between the medieval town of Grosseto and the Roman town of Roselle in central Italy. The site discussed in this paper was detected from the air during the Aerial Archaeology Research School organized by the University of Siena in 2001 (Campana et al. 2006). Aerial survey allowed us to recognize an area within which the growth of the wheat varied in such a way as to reveal an articulated group of traces that made up the plan of a complex of structures interpreted as a Roman villa, 4 hectares in extent. In the following years Aiali has become the most important test site for the Laboratory of Landscape Archaeology and Remote Sensing at Grosseto. Since 2001 we have collected, processed and interpreted many different kinds of data: Quickbird-2 satellite imagery, historical and recent vertical coverage (from 1954 to 2001), oblique air photographs in various years, seasons and lighting condition; field-walking survey, and in the course of the XV International Summer School in Archaeology at Grosseto several geophysical methods were tested for archaeological prospection at the Roman site at Roselle-Aiali for demonstration to the students. For the purpose of magnetic prospecting a highly automated system consisting of a 4-Foerster-probes (Ferex DLG) on a chart with GPS and a Overhauser magnetometer (GSM-19) were applied in the same grid. At the time of the summer school there was no caesium-magnetometer system available. Therefore the whole area had been remeasured some weeks later with a Scintrex Smartmag SM4G-special in various sensor configurations again in the same grid and under the same surface conditions for comparison (the magnetometer was made available for the test by Schweitzer-GPI company).