Coupled deep-water flow and climate variability in the middle Pleistocene North Atlantic

Kleiven, Helga (Kikki) F. and Hall, I. R. and McCave, I. N. and Knorr, G. and Jansen, E. (2011) Coupled deep-water flow and climate variability in the middle Pleistocene North Atlantic. Geology, 39. pp. 343-346. DOI 10.1130/G31651.1

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Abstract

Abrupt changes in the strength of the Atlantic Meridional Overturning Circulation (comprising northward flow of warm water and a cold southward return flow) are implicated in abrupt climate changes in the late Pleistocene. A sensitive place to assess this circulation is in the cold return flow of Deep Western Boundary Currents. Here, in records of flow speed and isotopic composition of surface and bottom waters from a Deep Western Boundary Current location near the northern source of North Atlantic Deep Water, we show both orbital and millennial-scale coupling between deep ocean flow and climate in the middle Pleistocene (0.75–0.87 Ma), when the boundary conditions in terms of the mean state and amplitude of climate change were different from more recent periods. The coupling appears as a phased series of events initiated by reduced vertical density gradients and initial ventilation of deep waters. The occurrence of these events in interglacials during the middle Pleistocene suggests that the millennial-scale climate variability in the North Atlantic was more pronounced at that time than previously thought. This demonstrates that, given the right boundary conditions, rapid climate shifts can also occur during relatively warm climate conditions.

Item Type: Article
Uncontrolled Keywords: 2011AREP; IA62;
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Geology
Volume: 39
Page Range: pp. 343-346
Identification Number: 10.1130/G31651.1
Depositing User: Sarah Humbert
Date Deposited: 25 Mar 2011 17:30
Last Modified: 23 Jul 2013 10:02
URI: http://eprints.esc.cam.ac.uk/id/eprint/2046

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