Catastrophic drainage from the northwestern outlet of glacial Lake Agassiz during the Younger Dryas
Lake Agassiz, Younger Dryas, meltwater drainage
Catastrophic meltwater drainage from glacial Lake Agassiz has been hypothesised as a trigger for large-scale ocean circulation change initiating the Younger Dryas cold reversal. Here we quantify the flood discharge that formed the northwestern outlet of Lake Agassiz using a one-dimensional step-backwater model and a zero-dimension gradual-incision model. Applying these two independent models, we estimate a peak discharge range of 1.8-2.5 × 106 m3 s-1 and a flood volume of ~21,000 km. Such a discharge can only be derived from Lake Agassiz rather than one of the two smaller regional glacial lakes: Churchill or Meadow. When coupled with existing ice margin chronologies, these results demonstrate that the northwestern outlet of Lake Agassiz provides a viable link for catastrophic meltwater to drain to the Arctic Ocean over a 5-10 month period during the Younger Dryas, though it is unclear whether this was near its beginning.
Norris, S.L., Garcia-Castellanos, D., Jansen, J.D., Carling, P.A., Margold, M., Woywitka, R., and Froese, D.G. (2021). Catastrophic drainage from the northwestern outlet of glacial Lake Agassiz during the Younger Dryas. Geophysical Research Letters, 48, e2021GL093919. https://doi.org/10.1029/2021GL093919
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