Anders E. Carlson: Response of the southern Greenland Ice Sheet during the last two deglaciations

Geology; May 2008; v. 36; no. 5; p. 359-362; DOI: 10.1130/G24519A.1
© 2008 Geological Society of America

Response of the southern Greenland Ice Sheet during the last two deglaciations

Anders E. Carlson^1,*, Joseph S. Stoner², Jeffrey P. Donnelly³ and Claude Hillaire-Marcel⁴

¹ Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
² College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
³ Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
⁴ GEOTOP, Université du Québec à Montréal, CP 8888, Montreal, Quebec H3C 3P8, Canada

The retreat of the southern Greenland Ice Sheet (GIS) during the last deglaciation (Termination I: TI) is poorly dated by conventional means; there is even greater uncertainty about the penultimate deglaciation (Termination II: TII), leading to the assumption that the southern GIS has a significant lag in its response to deglacial warming. Here we use geochemical terrestrial sediment proxies ([Fe] and [Ti]) from a well-studied southern Greenland marine sediment sequence to examine the behavior of the southern GIS during TI and TII. Our records show that during TI and TII the southern GIS response was essentially synchronous with deglacial North Atlantic warming, implying greater climate sensitivity than previously assumed. During TI, elevated ablation lasted ~5 k.y., whereas ablation remained elevated for ~12 k.y. during TII, suggesting a reduced southern GIS during TII that contributed a significant fraction of the higher sea level during the subsequent interglacial.

Key Words: southern Greenland Ice Sheet • deglaciation • sea level • ice sheet response