Catastrophic drainage from the northwestern outlet of glacial Lake Agassiz during the Younger Dryas

• Published in: Geophysical Research Letters
• Main Authors: Norris, Sophie, Garcia-Castellanos, Daniel, Jansen, John, Carling, Paul, Margold, Martin, Woywitka, RJ, Froese, Duane
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Arctic; Arctic Ocean; Glacial Lake
• Online Access: https://eprints.soton.ac.uk/450252/; https://eprints.soton.ac.uk/450252/1/Norris_et_al._2021_GRL_Catastrophic_drainage_from_NW_outlet_of_glacial_Lake_Agassiz.pdf

Catastrophic meltwater drainage from glacial Lake Agassiz has been hypothesized 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 × 10 6 m 3 s −1 and a flood volume of ∼21,000 km 3 . 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 6–9 month period during the Younger Dryas, though it is unclear whether this was near its beginning.