ELSEVIER Marine Geology 158 (1999) 197–208 www.elsevier.com/locate/margeo European contribution of ice-rafted sand to Heinrich layers H3 and H4 Hilde Snoeckx a,1 , Francis Grousset a,Ł , Marie Revel b , An Boelaert c a De ´partement de Ge ´ologie et Oce ´anographie, UMR 5805, Universite ´ Bordeaux I, Avenue des Faculte ´s, 33405 Talence cedex, France b LGCA, Institut Dolomieu, 15 rue M. Gignoux, 38031 Grenoble, France c DRO=GM Laboratoire Environnements Se ´dimentaires, IFREMER Centre de Brest, B.P. 70, 29280 Plouzane ´ cedex, France Received 6 February 1998; accepted 26 August 1998 Abstract This paper reports the Sr–Nd isotopic composition of the carbonate-free sand (>63 μm–1 mm) fraction of Heinrich layers 3 and 4 from about 17 cores from the northern Atlantic Ocean (38ºN to 68ºN). The results indicate that the transporting icebergs were calved from many ice sheets from around the North Atlantic (at least the Fennoscandian, Icelandic and Laurentide). Our isotopic data show a more distinctly European origin for ice-rafted debris (IRD) deposited during the ‘atypical’ Heinrich event H3 than for background IRD. In contrast, Heinrich layer H4, a representative of ‘typical’ Heinrich events H1, H2, H4, and H5, presents a clear dominant Laurentide signal. This result confirms that these ‘typical’ Heinrich events are associated with a massive discharge of icebergs from the Laurentide ice sheet. However, the theory that the Laurentide ice sheet set the events into motion [Alley, R.B., MacAyeal, D.R., 1993. Ice-rafted debris associated with binge=purge oscillations of the Laurentide Ice Sheet. Paleoceanography 9 (4), 503–511] cannot explain the fact that a European signal of an early-H4 sample has been observed prior to the Laurentide signature of a late-H4 sample in the same core, along the European margin. This observation indicates that the European ice sheets may have surged before the North American ones, and suggests that the Laurentide ice sheet was not the sole motor behind the Heinrich events. Moreover, in the Norwegian Sea, IRD has a Scandinavian origin in both H3 and H4.  1999 Elsevier Science B.V. All rights reserved. Keywords: Heinrich events; North Atlantic; Sr and Nd isotopes; ice-rafting; origins 1. Introduction Heinrich layers were deposited when melting ice- bergs unloaded their debris en masse in the North Atlantic Ocean. The icebergs were released at the culmination of some (but not all) cold climate cy- cles called Dansgaard–Oeschger events, within the 1 Present address: Environmental Studies Program, University of West Florida, Pensacola, FL 32514-5751, USA. Ł Corresponding author. Fax: C33 556-840-848; E-mail: grousset@geocean.u-bordeaux.fr last glacial period (Bond et al., 1992, 1993). The underlying cause of those short-term climate cycles is still an important gap in our understanding of the Earth’s climate system. The recent focus on high- resolution climate records has revealed that similar short-term climate cycles occur elsewhere in the world, including the Southern Hemisphere (Little et al., 1997) and that they may be concurrent with the Dansgaard–Oeschger and Heinrich events. Telecon- nections may link climate events recorded in Asian loess (Porter and Zhisheng, 1995) and glacial ad- vances in Chile and New Zealand (Lowell et al., 0025-3227/99/$ – see front matter  1999 Elsevier Science B.V. All rights reserved. PII:S0025-3227(98)00168-6