A Younger Dryas re-advance of local glaciers in north Greenland

QUATERNARY SCIENCE REVIEWS

卷:147

Article; Proceedings Paper

Larsen, Nicolaj K.^1,2  Funder, Svend²  Linge, Henriette^3,4  Moller, Per⁵  Schomacker, Anders^2,6  Fabel, Derek⁷  Xu, Sheng⁷  Kjaer, Kurt H.² 

[1] Aarhus Univ, Dept Geosci, Hoegh Guldbergs Gade 2, DK-8000 Aarhus C, Denmark

[2] Univ Copenhagen, Nat Hist Museum Denmark, Ctr GeoGenet, Oster Voldgade 5-7, DK-1350 Copenhagen K, Denmark

[3] Univ Bergen, Dept Earth Sci, Postbox 7803, N-5020 Bergen, Norway

[4] Bjerknes Ctr Climate Res, Postbox 7803, N-5020 Bergen, Norway

[5] Lund Univ, Dept Geol, S-22100 Lund, Sweden

[6] UiT Arctic Univ Norway, Dept Geol, N-9037 Tromso, Norway

[7] Scottish Univ Environm Res Ctr, AMS Lab, E Kilbride G75 0QF, Lanark, Scotland

关键词: Greenland ice sheet;    Younger Dryas;    Ice marginal fluctuations;    Surface exposure dating;   

DOI  :  10.1016/j.quascirev.2015.10.036

来源: Elsevier

【 摘 要 】

The Younger Dryas (YD) is a well-constrained cold event from 12,900 to 11,700 years ago but it remains unclear how the cooling and subsequent abrupt warming recorded in ice cores was translated into ice margin fluctuations in Greenland. Here we present 1 Be surface exposure ages from three moraines in front of local glaciers on a 50 km stretch along the north coast of Greenland, facing the Arctic Ocean. Ten ages range from 11.6 +/- 0.5 to 27.2 +/- 0.91 a with a mean age of 12.5 +/- 0.7 ka after exclusion of two outliers. We consider this to be a minimum age for the abandonment of the moraines. The ages of the moraines are furthermore constrained using Optically Stimulated Luminescence (OSL) dating of epishelf sediments, which were deposited prior to the ice advance that formed the moraines, yielding a maximum age of 12.4 +/- 0.6 ka, and bracketing the formation and subsequent abandonment of the moraines to within the interval 11.8-13.0 ka ago. This is the first time a synchronous YD glacier advance and subsequent retreat has been recorded for several independent glaciers in Greenland. In most other areas, there is no evidence for re-advance and glaciers were retreating during YD. We explain the different behaviour of the glaciers in northernmost Greenland as a function of their remoteness from the Atlantic Meridional Overturning Circulation (AMOC), which in other areas has been held responsible for modifying the YD drop in temperatures. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

Free