Open AccessComparison of glacial and interglacial conditions between the polar and subpolar North Atlantic region over the last five climatic cycles
Author(s) -
Helmke Jan P.,
Bauch Henning A.
Publication year - 2003
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/2002pa000794
Subject(s) - geology , interglacial , glacial period , deglaciation , oceanography , marine isotope stage , thermohaline circulation , iceberg , north atlantic deep water , climatology , polar , sea surface temperature , sea ice , paleontology , physics , astronomy
A multiparameter‐based interpretation of sediment records from the northeast Atlantic and the western Nordic seas suggests that during the last 500,000 years only in marine isotopes stage (MIS) 11, 5e, and 1 were there somewhat comparable interglacial boundary conditions in both regions, i.e., strongly reduced occurrence of iceberg‐rafted debris (IRD) and high carbonate bioproductivity. Although the northeast Atlantic experienced such conditions during all peak interglaciations, with the exception of MIS 7, planktic foraminiferal δ 18 O from this region would still indicate that significantly colder sea surface temperatures (SST) prevailed during MIS 11 than during MIS 9, 5e, and 1. This assumption is corroborated by a continuous input of IRD into the western Nordic seas during MIS 11, implying a much steeper SST gradient between the polar and subpolar region and an overall reduced thermohaline activity in the polar latitudes. The iceberg proxy also reveals that maximum IRD discharge always happened during the final phase of glaciation and into early deglaciation (terminations). As these IRD records from the two regions are characterized by a high time coherency, it is concluded that short‐term variability is a persistent feature of the glacial climate system.