Universität zu Köln

Weber, M. E., Clark, P. U., Kuhn, G., Timmermann, A., Sprenk, D., Gladstone, R., Zhang, X., Lohmann, G., Menviel, L., Chikamoto, M. O., Friedrich, T. and Ohlwein, C. (2014). Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation. Nature, 510 (7503). S. 134 - 147. LONDON: NATURE PUBLISHING GROUP. ISSN 1476-4687

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Abstract

Our understanding of the deglacial evolution of the Antarctic Ice Sheet (AIS) following the Last Glacial Maximum(26,000-19,000 years ago)(1) is based largely on a few well-dated but temporally and geographically restricted terrestrial and shallow-marine sequences(2-4). This sparseness limits our understanding of the dominant feedbacks between the AIS, Southern Hemisphere climate and global sea level. Marine records of iceberg-rafted debris (IBRD) provide a nearly continuous signal of ice-sheet dynamics and variability. IBRD records from the North Atlantic Ocean have been widely used to reconstruct variability in Northern Hemisphere ice sheets(5), but comparable records from the Southern Ocean of the AIS are lacking because of the low resolution and large dating uncertainties in existing sediment cores. Here we present two well-dated, high-resolution IBRD records that capture a spatially integrated signal of AIS variability during the last deglaciation. We document eight events of increased iceberg flux from various parts of the AIS between 20,000 and 9,000 years ago, in marked contrast to previous scenarios which identified the main AIS retreat as occurring after meltwater pulse 1A(3,6-8) and continuing into the late Holocene epoch. The highest IBRD flux occurred 14,600 years ago, providing the first direct evidence for an Antarctic contribution to meltwater pulse 1A. Climate model simulations with AIS freshwater forcing identify a positive feedback between poleward transport of Circumpolar Deep Water, subsurface warming and AIS melt, suggesting that small perturbations to the ice sheet can be substantially enhanced, providing a possible mechanism for rapid sea-level rise.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Weber, M. E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Clark, P. U. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kuhn, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Timmermann, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Sprenk, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gladstone, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zhang, X. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lohmann, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Menviel, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Chikamoto, M. O. UNSPECIFIED UNSPECIFIED UNSPECIFIED Friedrich, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ohlwein, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-435968
DOI:	10.1038/nature13397
Journal or Publication Title:	Nature
Volume:	510
Number:	7503
Page Range:	S. 134 - 147
Date:	2014
Publisher:	NATURE PUBLISHING GROUP
Place of Publication:	LONDON
ISSN:	1476-4687
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language PINE ISLAND GLACIER; SOUTHERN-OCEAN; WEDDELL SEA; SCOTIA SEA; RADIOCARBON CONSTRAINTS; CIRCUMPOLAR CURRENT; RETREAT; CORE; CHRONOLOGY; MAXIMUM Multiple languages Multidisciplinary Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/43596