Publikationsdatum:
2024-06-20
Beschreibung:
Over the last 25 years, Canadian scientists have studied the permafrost environmental archives in the Klondike Goldfields south of Dawson City (e.g. Fraser and Burn, 1997; Kotler and Burn, 2010; Froese et al., 2009; Porter et al., 2016; Monteath et al., 2023). In 2023, a small Canadian-German team visiting this area to sample mining exposures in the Klondike area (Figure 1A). The goal was to conduct studies on ground ice (ice wedges and pore ice) and frozen sediments to reconstruct past landscape and climate conditions. Detailed profiles were sampled at three sites at Little Blanche Creek, Whitman Gulch and Bear Creek.
Ice wedges were described in terms of their size, the color of ice, internal structure, existence and form of gas bubbles and were sampled by chain saw as blocks. The frozen sediment was cleaned, and ice, sediment and cryostructures were described, followed by sediment sampling with an axe and hammer. Separately, sediment cores were collected with a battery driven drill for biomarker studies.
In our presentation, we present the first results of new field and laboratory studies. This concerns age determinations, sediment data, stable isotopes and hydrochemistry of the ground ice. The mean ice content measured was 38 ± 10 wt%.
We expect new knowledge regarding the reconstruction of Late Quaternary environment of Central Yukon.
References
Fraser, T.A. and Burn, C.R. 1997: On the nature and origin of "muck" deposits in the Klondike area, Yukon Territory, Canadian Journal of Earth Sciences 34(10), 1333-1344, https://doi.org/10.1139/e17-106.
Froese, D., Zazula, G., Westgate, J., Preece, S., Sanborn, P. A., Reyes, A., and Pearce, N. 2009: The Klondike goldfields and Pleistocene environments of Beringia, GSA Today, 19, 4-10, https://doi.org/10.1130/GSATG54A.1.
Kotler, E. and Burn, C. R. 2000: Cryostratigraphy of the Klondike "muck" deposits, west-central Yukon Territory, Can. J. Earth Sci., 37, 849-861, https://doi.org/10.1139/e00-013.
Monteath, A. J., Kuzmina, S., Mahony, M., Calmels, F., Porter, T., Mathewes, R., Sanborn, P., Zazula, G., Shapiro, B., Murchie, T. J., Poinar, H. N., Sadoway, T., Hall, E., Hewitson, S., and Froese, D. 2023: Relict permafrost preserves megafauna, insects, pollen, soils and pore-ice isotopes of the mammoth steppe and its collapse in central Yukon, Quaternary Science Reviews, 299, 107878, https://doi.org/10.1016/j.quascirev.2022.107878.
Porter, T. J., Froese, D. G., Feakins, S. J., Bindeman, I. N., Mahony, M. E., Pautler, B. G., Reichart, G. J., Sanborn, P. T., Simpson, M. J., and Weijers, J. W. H. 2016: Multiple water isotope proxy reconstruction of extremely low last glacial temperatures in Eastern Beringia (Western Arctic), Quaternary Science Reviews, 137, 113-125, https://doi.org/10.1016/j.quascirev.2016.02.006.
Repository-Name:
EPIC Alfred Wegener Institut
Materialart:
Conference
,
NonPeerReviewed
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