Magnetic Gradient Surveys Applied for Investigating the Archaeological Site Orgame/ Argamum, Romania

The present paper studies how successfully magnetic gradient surveys can be used in order to investigate archaeological sites. Orgame/Argamum site dated to V. Century B.C., is located in Tulcea County, Romania, and it has proved to be one of the biggest sites in Romania; this required a number of additional investigations before excavations could start. The Faculty of Geology and Geophysics conducted a number of geophysical investigations on this site in the summer of 2011, including magnetic gradient and GPR surveys and resistivity profiling. The image maps obtained through these methods revealed many circular buried structures, described by the archaeologists as antique tombs. After sharing the results with the archaeologists, they decided to start excavating. The image maps obtained through the use of different geophysical methods proved to be very accurate. Magnetic gradient surveys revealed great results for investigating this archaeological site. The image map obtained through this method shows that the walls determine an increase of the magnetic gradient, whereas the central part of the circular walls, filled with soil, have a weaker magnetic response. This allows a approximative determination of the form of the walls and can be extrapolated for structures whose shape is not known.