Somogyvári Ágnes et al. (szerk.): Településtörténeti kutatások - Archaelogia Cumanica 3. (Kecskemét, 2014)
Castrum Tétel program (Solt–Tételhegy) eredmények és perspektívák - Puszta Sándor: Felszíni mágneses kutatások a Tételhegy területén
ARCHAEOLOGIA CUMANICA 3 Sándor Puszta Geophysical investigations on the Tételhegy site Iron of a different condition and concentration than its environment lying near the surface alters the magnetic environment. Measurements based on high-density surface points can yield important information on archaeological features. This physical phenomenon provided a wealth of information on archaeological structures and other features in the Solt-Tételhegy research area that were identified as ditches, pits, corrals and ovens during the subsequent excavations. We used a GSM-19 (Overhauser) magnetometer by GEM Systems for the survey. We took measurements on the points of the 1 m x 1 m grid and along lines running 0.5-1 m from each other with a point average of 0.5 m. The grids were laid out using a theodolite with an average point distance of 0.5 m, while GPS navigation using a TRIMBLE GPS system was employed in the case of the latter. The co-ordinates of each point were treated as data of sub-meter accuracy. We also measured the magnetic susceptibility of the surveyed area using equipment by Bartington Instruments. The size of the surveyed area was 11.6 ha, accounting for about one-eighth of the 88 ha large area of the Tételhegy site. The study describes the successive steps in the assessment of the magnetic data: measurement noise reduction; base correction; dynamic compression; interpolation of the data; filtering of the magnetic maps; extrapolation of the data; calculation of the two-dimensional Fourier spectrum; calculation of the radial power spectra; low pass filtering of the data; direction dependent filtering of the data; downward continuation of the data; reduction to the pole; optimum (Wiener) smoothing filtering; phase only map; coherence enhancement. The results of the magnetometer survey of the Tételhegy site were visually presented on a combined map that was based on an aerial photo (Fig. 1), while the various details were illustrated independently (Figs 2-4). One important step in the assessment of the data is the so-called downward continuation of the data (Figs 5-6). Two interesting cases based on local susceptibility measurements are highlighted: the susceptibility map of the burnt base of an oven (Figs 7-9) and the susceptibility function measured on the wall of the prehistoric ditch and rampart ringing the Templomdomb in the northern part of the surveyed area, which illustrated the correlation between the function and the optical traits of the section (Fig 10). 58
