Sediments reveal that lead and zinc mining potentially started already between AD 550-1030 around Muttatjern, Hadeland, Norway

The use of lake sediments as a natural archive provides insights into past anthropogenic activities, such as mining. The first archaeological evidence of copper mining in Norway dates back to AD 1200-1300 in Meråker, around the same time as copper mining had started in Falun, Sweden. However, incomplete archeological evidence prevents us from fully understanding the long history of mining in Scandinavia. By analyzing geochemical data stored within lake sediments it is possible to evaluate concentrations of trace elements and thereby determine when anthropogenic activities began. To do this, a complete sediment profile was taken from the small lake of Muttatjern located in Hadeland county, north of Oslo in early 2024. The geochemical analysis revealed that a pronounced peak occurred at 14 cm for Pb, Zn and S, followed by a smaller peak occurring at 70 cm for Pb and Zn, as well as a smaller peak at 100 cm for Pb. Based on the age-depth model of when spruce became prominent in Hadeland, a timeline was created for each of the presented peaks. The peak at 14 cm is most likely related to the known mining period between AD 1900-1930 when Zn and Pb ore was extracted at Muttatjern. Furthermore, the peak occurring at 70 cm for Pb and Zn was dated to AD 550-1030, which is approximately during the same period when Scandinavian Pb-ore was used between AD 375-700. Overall, my results illustrate that mining around Lake Muttatjern could have started already between AD 550-1030.