Red-coated rocks on the seashore: The esthetics and geology of prehistoric rock art in Alta, Arctic Norway

Abstract

Research suggests that the World Heritage rock engravings in Alta, Northern Norway, were made along the seashore over a period of 5000 years. The postglacial rebound and consequent land uplift have caused a continuous displacement of the shoreline, now situating the earliest rock art panels up to 26 m above sea level. By examining the rock surfaces at Hjemmeluft and other sites, using field observations and geological analyses, we found that the pronounced red bedrock surfaces in the current seashore zone are composed of inorganic iron films related to a high content of magnetite in the native sandstone. Coupled with an interpretation of regional environmental history, we also found that it is highly likely that the rock art was originally carved on rocks with red iron films, rocks that are now generally gray. Due to the land uplift and subsequent covering of the rock art with lichen, moss, and turf, the red color has waned at the rock art sites. This knowledge may renew interpretation and understanding of the location of rock art in Alta and may have implications for conservation and management.