Gold Mining as key to Eastern Beringia - Impressions from the AWI Expedition 2023 to the Klondike Goldfields

In the summer of 2023, three colleagues from the AWI Research Unit Potsdam worked together with two Canadian colleagues from the University of Toronto on permafrost outcrops in the vicinity of Dawson City. Dawson City is located in western Canada in the Yukon Territory near the Alaskan border at the mouth of the Klondike River into the Yukon and is known for its gold mining. During the Klondike Gold Rush at the end of the 19th century, tens of thousands of gold miners had spent several years in the Klondike Goldfields digging shafts in the permafrost with fires during the winter, driving tunnels horizontally and bringing the gold-bearing gravels to the surface. In the early 20th century through the 1960s, gold was washed out on a large scale in the main valleys with huge dredges, massively altering the landscape. Today, dozens of smaller and larger gold mines extract the gold placers and further alter the landscape. Huge sand and gravel mountains and long gravel walls with little vegetation cover can still be found on the valley floors today. The very continental climate in the study area leads to very cold winters (up to -50°C) and very warm summers. With temperatures up to 30°C and a very low mosquito density, we were able to sample the permafrost partly in T-shirts. Another consequence of the dry heat with only a few thundershowers were over 100 forest fires in the region, which, in addition to frequent smoke in Dawson City and the surrounding area, also led to evacuations of towns in the wider area and road closures. In the secondary valleys, the ice-rich permafrost overlying gold-bearing gravels is still being thawed with water cannons and removed with excavators. This created short-term opportunities for us to examine fresh permafrost walls. Our group examined and sampled both the long and wide ice wedges and the surrounding ice-rich sediment. Studies of ice chemistry and ice isotopy are planned. Different age determination methods will be carried out on the sediments and the ice. The sediments will be analyzed for grain size, carbon and nitrogen contents, and biomarkers, among other things, and will be available for paleoecological studies to reconstruct environmental conditions before, during, and after the last ice age. We would like to give you an impression of this expedition with some pictures and background information.

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