Remnant echoes of the past Archaeological geophysical prospection in Sweden

Abstract: The aim of this thesis has been to investigate the benefits, pitfalls and possibilities of using geophysical methods in archaeological projects. This is exemplified by surveys carried out at archaeological sites in different geographical and chronological contexts. The thesis also aims at investigating the cause for the under-use of the methods in Swedish archaeology by looking at previously conducted surveys. The methods used during these surveys have been Ground-penetrating radar (GPR), magnetometer, slingram and a kappameter. The surveys in the mountain tundra region of Lapland show that magnetic susceptibility surveys is a valuable aid in discovering heaps of fire-cracked stones and when combined with magnetometry, also hearths. GPR and magnetometer surveys within the Migration Period ringfort Sandbyborg provided the spatial layout of the fort and indicated, along with results from recent excavations and metal detections, many similarities with the ringfort Eketorp II. The non-magnetic character of the sedimentary bedrock on Öland and Gotland is suitable for magnetometer surveys and the method is also highly appropriate for the detection of the remains of high-temperature crafts. GPR surveys at St. Mary’s Dominican convent in Sigtuna produced the spatial layout of the central cloister area. The investigations also show that the geology, pedology, land use and the character of commonly occurring prehistoric remains in Sweden, in certain circumstances and in certain areas, have restricted the possibility of successfully carrying out geophysical surveys. Care must therefore be taken to choose the right instrument for the survey and to tailor the sampling density of each geophysical survey, according to the character and size of the expected archaeological remains, in order to maximize their information return. To increase the use of geophysical methods in Sweden the educational opportunities, both for surveyors and professional archaeologists, need to improve.