Application of magnetometry, georadar (GPR) and geoelectrical methods in archaeo-geophysical investigation of a Napoleonic battlefield with fortification at Pressburg (Bratislava, Slovakia)

Abstract

This article presents the successful application of several geophysical methods in archaeological prospection with integration of LiDAR data and examination of historical documents. The locality of interest is situated in an urban area of Bratislava city on the Danube River where no previous archaeological research has been undertaken. It comprises the oldest public park in Central Europe which is surrounded by a fortification system dating to the Napoleonic siege of Pressburg (Bratislava) in 1809. Urban areas are often challenging for conducting archaeo-geophysical investigation due to limited access and existing obstacles of modern origin.For the purposes of this investigation shallow geophysical survey methods were applied including magnetometry, ground penetrating radar (GPR), 2D electrical resistivity tomography (ERT) and electrical resistance survey. Magnetometry was used to obtain a general view of the survey areas and to help to target the following surveys. ERT and GPR were used to explore detected features in more detail and obtain information about their shape and depth. The results of the survey show the importance of the combined approach using multiple geophysical methods while also highlighting their benefits and limitations.The survey was successful in investigating the basic elements of the fortification system which includes a rampart, a ditch and a bastion. The results have revealed information about the current state of the ramparts as well as their original construction. Also, the previously unrecorded remains of a bastion were identified along with previous phases of the fortification. The results obtained reveal the archaeological potential of this historical locality and help to better understand its extension, which is essential for its future protection and development.