ADAPTING LEGACY MAGNETOMETRY DATA FOR ARCHAEOLOGICAL SITE ANALYSIS: AN EXAMPLE FROM THE GREVENA PROJECT SURVEY, GREECE

Reanalysis of magnetometry legacy data at Itea Panaghia/Profitis Ilias, a multi-period archaeological site in the Grevena prefecture, western Macedonia, Greece, reveals the magnetic signature of a possible buried structure. The site is a prominent landmark on a ridge end near the confluence of several streams. Field surveying of the site, including magnetometry, took place from 1987-89 as part of the Grevena Project, a multidisciplinary archaeological survey of the 2500 km² prefecture. Magnetometry results were re-analyzed in 2014-2016 with the goal of determining whether the uniform upper surface of the site conceals any now-buried structures.

Field-based evidence supports a complex history at this location, suggesting its function as a settlement, convent and church across time. The Itea Panaghia/Profitis Ilias site was occupied in the Bronze Age (Late?), Iron Age, Geometric, Archaic, Classical, Hellenistic, Late Roman, Early Medieval and post-Byzantine periods, judging from pottery fragments found at the ground surface. A road cut at the site exposes a pebble floor consistent with an Archaic building of some kind, as suggested by a radiocarbon date and associated potsherds. A rich oral history revolves around an 18^th-century church (destroyed by a 1995 earthquake) and a convent (demolished 1912).

Magnetometry surveys, collected on a four meter grid with a single proton-precession magnetometer, cover 8500 m². When compiled and interpreted, the two legacy datasets reveal a linear anomaly of two parallel magnetic lows 12 m apart stretching E-W for at least 100 meters, possibly representing a building foundation, as well as several discrete dipolar anomalies. The geophysical data do not seem to show an extension of the pebble floor, perhaps because there is little magnetic contrast between the pebble layer and the enclosing material.

Despite advances in the technology and methods of remote sensing in archaeological contexts over the last three decades, revisiting legacy data with modern processing techniques and the subsequent interpretation of these results proved feasible at numerous sites around the Grevena nomos. As illustrated at Itea Panaghis/Profitis Ilias, newly interpreted geophysical legacy data successfully augment the overall understanding of a site’s human history.