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Science
Vol. 328 no. 5983 pp. 1262-1266
DOI: 10.1126/science.1187860
  • Report

Freshwater Outburst from Lake Superior as a Trigger for the Cold Event 9300 Years Ago

  1. James T. Teller9
  1. 1Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN 55812, USA.
  2. 2Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA 70118, USA.
  3. 3Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN 55812, USA.
  4. 4Department of Geology, University of Cincinnati, Cincinnati, OH 45221, USA.
  5. 5Department of Earth Sciences, University of Ottawa, Ottawa, Ontario ON K1N 6N5, Canada.
  6. 6Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA.
  7. 7Department of Geology, Mercyhurst College, Erie, PA 16546, USA.
  8. 8Department of Anthropology, Lakehead University, Thunder Bay, Ontario ON P7B 5E1, Canada.
  9. 9Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba MB R3T 2N2, Canada.
  1. *To whom correspondence should be addressed. E-mail: syu2{at}tulane.edu

Abstract

Paleoclimate proxy records reveal a pervasive cooling event with a Northern Hemispheric extent ~9300 years ago. Coeval changes in the oceanic circulation of the North Atlantic imply freshwater forcing. However, the source, magnitude, and routing of meltwater have remained unknown. Located in central North America, Lake Superior is a key site for regulating the outflow of glacial meltwater to the oceans. Here, we show evidence for an ~45-meter rapid lake-level fall in this basin, centered on 9300 calibrated years before the present, due to the failure of a glacial drift dam on the southeast corner of the lake. We ascribe the widespread climate anomaly ~9300 years ago to this freshwater outburst delivered to the North Atlantic Ocean through the Lake Huron–North Bay–Ottawa River–St. Lawrence River valleys.

  • Received for publication 2 February 2010.
  • Accepted for publication 23 April 2010.