Acknowledgements
This research was funded by Nordforsk Centre of Excellence for Resource Extraction and Sustainable Arctic Communities (REXSAC, project no. 76938). Fieldwork was funded by Göran Gustafsson Foundation and EU INTERACT (International Network for Terrestrial Research and Monitoring in the Arctic) Transnational Access project ”Baseline Conditions and Arctic Mining Impacts under Hydro-Climatic Change (BCAM)”. Additionally this paper has been supported by the Kazan Federal University Strategic Academic Leadership Program. We further acknowledge Heike Siegmund (Dept. of Geological Sciences) at the laboratory at Stockholm University for her helpful assistance during the sulfur isotope analysis. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.