title: South Greenland ice-sheet collapse during Marine Isotope Stage 11.
abstract: Varying levels of boreal summer insolation and associated Earth system feedbacks led to differing climate and ice-sheet states during late-Quaternary interglaciations. In particular, Marine Isotope Stage (MIS) 11 was an exceptionally long interglaciation and potentially had a global mean sea level 6 to 13 metres above the present level around 410,000 to 400,000 years ago, implying substantial mass loss from the Greenland ice sheet (GIS). There are, however, no model simulations and only limited proxy data to constrain the magnitude of the GIS response to climate change during this 'super interglacial', thus confounding efforts to assess climate/ice-sheet threshold behaviour and associated sea-level rise. Here we show that the south GIS was drastically smaller during MIS 11 than it is now, with only a small residual ice dome over southernmost Greenland. We use the strontium-neodymium-lead isotopic composition of proglacial sediment discharged from south Greenland to constrain the provenance of terrigenous silt deposited on the Eirik Drift, a sedimentary deposit off the south Greenland margin. We identify a major reduction in sediment input derived from south Greenland's Precambrian bedrock terranes, probably reflecting the cessation of subglacial erosion and sediment transport as a result of near-complete deglaciation of south Greenland. Comparison with ice-sheet configurations from numerical models suggests that the GIS lost about 4.5 to 6 metres of sea-level-equivalent volume during MIS 11. This is evidence for late-Quaternary GIS collapse after it crossed a climate/ice-sheet stability threshold that may have been no more than several degrees above pre-industrial temperatures.
authors: 1] Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, USA [2] School of Geography, Archaeology and Palaeoecology, Queen's University Belfast, Elmwood Avenue, Belfast BT7 1NN, UK [3] Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada (A.V.R); Department of Geosciences, University of Arizona, 1040 East 4th Street, Tucson, Arizona 85721, USA (B.W.).
authors: Alberto V
authors: AV
authors: Reyes
authors: 1] Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, USA [2] College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, Oregon 97331, USA.
authors: Anders E
authors: AE
authors: Carlson
authors: Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, USA.
authors: Brian L
authors: BL
authors: Beard
authors: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, Oregon 97331, USA.
authors: Robert G
authors: RG
authors: Hatfield
authors: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, Oregon 97331, USA.
authors: Joseph S
authors: JS
authors: Stoner
authors: Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, USA.
authors: Kelsey
authors: K
authors: Winsor
authors: 1] Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, USA [2] Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada (A.V.R); Department of Geosciences, University of Arizona, 1040 East 4th Street, Tucson, Arizona 85721, USA (B.W.).
authors: Bethany
authors: B
authors: Welke
authors: 1] Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, USA [2] College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, Oregon 97331, USA.
authors: David J
authors: DJ
authors: Ullman