Correlations between climate records from North Atlantic sediments and Greenland ice 

Nature, 365, p. 143-147, 1993. 

G. Bond
Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA.
W. Broecker
S. Johnsen
Geofysisk Afdeling, Niels Bohr Instituttet for Astronomi, Fysik og Geofysik, Københavns Universitet
J. McManus
L. Labeyrie
J. Jouzel
B. Bonani

Oxygen isotope measurements in Greenland ice demonstrate that a series of rapid wann-cold oscillations -called Dansgaard-Oeschger events-punctuated the last glaciation. Here we present records of sea surface temperature from North Atlantic sediments spanning the past 90 kyr which contain a series of rapid temperature oscillations closely matching those in the ice-core record, confirming predictions that the ocean must bear the imprint of the Dansgaard-Oeschger events. Moreover, we show that between 20 and 80 kyr ago, the shifts in ocean-atmosphere temperature are bundled into cooling cycles lasting on average 10 to I5 kyr, with asymmetrical saw-tooth shapes. Each cycle culminated in an enormous discharge of icebergs into the North Atlantic (a Heinrich event'), followed by an abrupt shift to a warmer climate. These cycles document a previously unrecognized link between ice sheet behaviour and ocean-atmosphere temperature changes. An important question that remains to be resolved is whether the cycles are driven by external factors, such as orbital forcing, or by internal ice-sheet dynamics.