Warming of surface waters in the mid-latitude North Atlantic during Heinrich events

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doi: 10.1029/2012PA002354
Author(s): Naafs, B. David A.; Hefter, J.; Grützner, J.; Stein, R.
Author Affiliation(s): Primary:
Alfred Wegener Institute for Polar and Marine Research, Department of Marine Geology and Paleontology, Bremerhaven, Germany
Volume Title: Paleoceanography
Source: Paleoceanography, 28(1), p.153-163. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 85 refs.; illus., incl. 1 table, sketch map
Summary: During the six Heinrich events of the last 70 kyr, episodic calving from the circum-Atlantic ice sheets released large numbers of icebergs into the North Atlantic. These icebergs and associated meltwater flux are hypothesized to have led to a shutdown of Atlantic Meridional Overturning Circulation and severe cooling in large parts of the Northern Hemisphere. However, due to the limited availability of high-resolution records, the magnitude of sea surface temperature (SST) changes related to the impact of Heinrich events on the midlatitude North Atlantic is poorly constrained. Here we present a record of UK37l-based SSTs derived from sediments of Integrated Ocean Drilling Project Site U1313, located at the southern end of the ice-rafted debris (IRD) belt in the midlatitude North Atlantic (41°N). We demonstrate that all six Heinrich events are associated with a rapid warming of surface waters by 2-4°C in a few thousand years. The presence of IRD leaves no doubt about the simultaneous timing and correlation between rapid surface water warming and Heinrich events. We argue that this warming in the midlatitude North Atlantic is related to a northward expansion of the subtropical gyre during Heinrich events. As a wide range of studies demonstrated that in the central IRD belt Heinrich events are associated with low SSTs, these results thus identify an antiphased (seesaw) pattern in SSTs during Heinrich events between the midlatitude (warm) and northern North Atlantic (cold). This highlights the complex response of surface water characteristics in the North Atlantic to Heinrich events that is poorly reproduced by freshwater hosing experiments and challenges the widely accepted view that, within the IRD belt of the North Atlantic, Heinrich events coincide with periods of low SSTs. Abstract Copyright (2012), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Alkenones; Atlantic Ocean; Biogenic structures; Bioturbation; Cenozoic; Debris; Expedition 303; Expedition 306; Expeditions 303/306; Heinrich events; IODP Site U1308; IODP Site U1313; Ice rafting; Integrated Ocean Drilling Program; Ketones; Marine environment; Mid-Atlantic Ridge; North Atlantic; Northeast Atlantic; Organic compounds; Paleo-oceanography; Paleoclimatology; Paleoenvironment; Paleotemperature; Pleistocene; Quaternary; Sea-surface temperature; Sedimentary structures; Upper Pleistocene
Coordinates: N410000 N410000 W0325700 W0325700
N495300 N495300 W0241400 W0241400
Record ID: 2014000261
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom