Die Geoelektrische Widerstandstomographie als Methode zur Abbildung archäologischer Strukturen - Eine vergleichende Studie aus Südwestdeutschland

Abstract

Electrical resistivity tomography (ERT) is gaining in importance in the field of archeological site prospecting. This contrasting study examines the results of mapping archeological structures and the resulting archeological excavation results. The study aims to show the boundaries of interpreting ERT scans and possible sources of error in interpreting ERT scan results. To accomplish this, ERT scans were performed at two selected sites in South West Germany. The results were then compared with later archeological excavation findings at these sites. Studies at the quadrangular Celtic enclosure near Sinsheim-Duhren in the Kraichgau have shown that the perimeter of V-shaped ditches can be distinguished well from the surrounding bed rock and back-fill. The resolution of the perimeter is not without uncertainty but the uncertainty is on such a minor scale that it does not affect the planning of an archeological dig at the site in question. Artifacts in ERT measurement interpretations could be linked to computational difficulties in the inversion routines. The impact of such artifacts depend on the chosen calculation configuration though. As a result of the measurements taken at Gewann Steinbock near Sinsheim-Duhren a soil map was created. More importantly though, the unique Celtic tomb was accurately localized within the quadrangular Celtic enclosure with the help of ERT. Research at a celtic ore smelting site in the Grosseltal near Neuenburg (Enzkreis) in the northern Black Forrest showed that the interpretation of data taken near lightly slag-rich heaps in partially rocky terrain is not possible without error. Also, localizing and determining the extent of the bloomeries could not be determined reliably via the ERT method. The ability to successfully localize the extracting traces of the celtic ore smelting site via the ERT method though were proven. After inspecting the sight for visible terraces with advancing upstream heaps, in depth ERT scans could be performed to localize access shafts, binges or other cavities in the perimeter of the terrace. Artifacts in ERT measurement could in turn be linked to computational difficulties in the inversion routines. A current limit to the ERT method lies in interlocked archeological finds in combination with the inversion routine interpretation. The ability to be able to distinguish between misinterpretations and actual archeological finds therefore is important.