Rock Art Research

When a new highway in SE Norway was planned in 2003, five petroglyph sites, located in the immediate surroundings of the road, were to be permanently covered. The covers consist of c. 70-cm-thick layers of plastic Quaternary marine clay on the rock art, followed by a geotextile, a thin drainage layer of natural gravel and finally a rather thick top layer of cobble stones. The clay serves to sustain a stable temperature, humidity and circumneutral pH at the rock surface and to prevent the establishment of plant roots. The purpose of the covers was to prevent increased deterioration rates of the rock art due to emissions from traffic and action from de-icing salts used on the road. This paper presents the cover design developed for this project, based on principles from the geotechnical, geochemical, biological and conservation fields. Subsequently, the paper demonstrates the success of a cross-disciplinary approach to rock art protection.