Evidence for Massive Discharges of Icebergs into the North-Atlantic Ocean during the Last Glacial Period

Publication Status is "Submitted" Or "In Press: 
Yes
LDEO Publication: 
Yes
Publication Type: 
Year of Publication: 
1992
Editor: 
Journal Title: 
Nature
Journal Date: 
Nov 19
Place Published: 
Tertiary Title: 
Volume: 
360
Issue: 
6401
Pages: 
245-249
Section / Start page: 
Publisher: 
ISBN Number: 
0028-0836
ISSN Number: 
Edition: 
Short Title: 
Accession Number: 
ISI:A1992JY96000046
LDEO Publication Number: 
Call Number: 
Key Words: 
Abstract: 

SEDIMENTS in the North Atlantic ocean contain a series of layers that are rich in ice-rafted debris and unusually poor in foraminifera1. Here we present evidence that the most recent six of these 'Heinrich layers', deposited between 14,000 and 70,000 years ago, record marked decreases in sea surface temperature and salinity, decreases in the flux of planktonic foraminifera to the sediments, and short-lived, massive discharges of icebergs originating in eastern Canada. The path of the icebergs, clearly marked by the presence of ice-rafted detrital carbonate, can be traced for more than 3,000 km-a remarkable distance, attesting to extreme cooling of surface waters and enormous amounts of drifting ice. The cause of these extreme events is puzzling. They may reflect repeated rapid advances of the Laurentide ice sheet, perhaps associated with reductions in air temperatures, yet temperature records from Greenland ice cores appear to exhibit only a weak corresponding signal. Moreover, the 5-10,000-yr intervals between the events are inconsistent with Milankovitch orbital periodicities, raising the question of what the ultimate cause of the postulated cooling may have been.

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Jy960Times Cited:621Cited References Count:28

DOI: