Proxy data reveal the existence of episodes of increased deposition of ice-rafted detritus in the North Atlantic Ocean during the last glacial period interpreted as massive iceberg discharges from the Laurentide Ice Sheet. Although these have long been attributed to self-sustained ice sheet oscillations, growing evidence of the crucial role that the ocean plays both for past and future behavior of the cryosphere suggests a climatic control of these ice surges. Here, we present simulations of the last glacial period carried out with a hybrid ice sheet-ice shelf model forced by an oceanic warming index derived from proxy data that accounts for the impact of past ocean circulation changes on ocean temperatures. The model generates a time series of iceberg discharge that closely agrees with ice-rafted debris records over the past 80 ka, indicating that oceanic circulation variations were responsible for the enigmatic ice purges of the last ice age.
Alvarez-Solas, J., Universidad Complutense de Madrid, 28040 Madrid, Spain, Instituto de Geociencias, Consejo Superior de Investigaciones Científicas-Universidad Complutense de Madrid, 28040 Madrid, Spain; Robinson, A., Universidad Complutense de Madrid, 28040 Madrid, Spain, Instituto de Geociencias, Consejo Superior de Investigaciones Científicas-Universidad Complutense de Madrid, 28040 Madrid, Spain; Montoya, M., Universidad Complutense de Madrid, 28040 Madrid, Spain, Instituto de Geociencias, Consejo Superior de Investigaciones Científicas-Universidad Complutense de Madrid, 28040 Madrid, Spain; Ritz, C., Laboratoire de Glaciologie et de Géophysique de L'Environnement, Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5183), F-38041 Grenoble, France, Université Grenoble Alpes, Laboratoire de Glaciologie et de Geophysique de L'Environnement (Unite Mixte de Recherche 5183), F-38041 Grenoble, France
Recommended Citation:
Alvarez-Solas J.,Robinson A.,Montoya M.,et al. Iceberg discharges of the last glacial period driven by oceanic circulation changes[J]. Proceedings of the National Academy of Sciences of the United States of America,2013-01-01,110(41)