Over the past few years Karin Tansem of the Tromsø Arctic University and Alta World Heritage Rock Art Centre and I have investigated the hypothesis that the famous rock engravings in Alta originally was made on strongly red-coloured bedrock along the seashore. The post-glacial land uplift has subsequently displaced the rock art and the colour has almost completely waned, leaving the rocks dull grey, as we know them today. Now we are happy that our work is finally published as an open-access paper, with Karin as driving force and lead author, in the international journal Geoarchaeology! Here’s the abstract explaining the phenomenon and its implications, and a link to the full paper.
Red-coated rocks on the seashore: The esthetics and geology of prehistoric rock art in Alta, Arctic Norway
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.
Reference and link to open-access paper
Tansem, K. & Storemyr, P. (2020). Red-coated rocks on the seashore: The esthetics and geology of prehistoric rock art in Alta, Arctic Norway. Geoarchaeology, early view, open access, 1–21. https://doi.org/10.1002/gea.21832
I want to thank you, Karin, for taking me onboard the project. It has been a true pleasure!