Large-Scale High-Resolution GPR Prospection in the Viking Age Landscapes of Southern Norway

Abstract

The development of motorized high-resolution GPR devices and corresponding processing and visualization tools is one of the main tasks within the 2010 in Vienna established Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology. Various case study areas have been selected in central and northern Europe in order to test and deploy the developed systems in different landscapes comprising various geological and archaeological settings. One of the case studies is situated in Vestfold County in southern Norway, an area best known for its exceptional Viking Age sites, such as the renowned 9th Century ship-burials at Gokstad and Oseberg, the trading and harbour site of Kaupang, as well as royal burial site at Borre National Park. In geological terms the area is dominated on a small-scale by glacial and marine erosional and depositional processes dating to the last glacial period, therefore displaying a rather challenging and variable geological setting for the application of near-surface geophysical prospection methods for archaeological objectives. Within several fieldwork campaigns over the past four years different motorized GPR survey systems (Sensors & Software SPIDAR array, MALÅ Imaging Radar Array) have been deployed and tested. Rather stable snow conditions in Northern Europe allowed the extension of the survey periods into wintertime and the use of multichannel GPR arrays towed by a snowmobile. In the vicinity of already known outstanding archaeological sites the survey areas have been extended onto the scale of the surrounding landscapes. Up to date an overall area of more than three square kilometres could be surveyed with unprecedented high resolution. In this paper we present the novel technology and methodology as well as latest archaeological discoveries, such as a newly mapped Viking Age harbour and trading site at Gokstad and impressive Viking Age hall-buildings found at Borre.