Accelerated drawdown of meridional overturning in the late-glacial Atlantic triggered by transient pre-H event freshwater perturbation
Hall, Ian R. (Cardiff University. School of Earth, Ocean, and Planetary Sciences)
Moran, S. B. (University of Rhode Island. Graduate School of Oceanography)
Zahn, Rainer (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Knutz, Paul C. (Danmarks og Grønlands geologiske undersøgelse)
Shen, C.-C. (Guo li Taiwan da xue. Department of Geosciences)
Edwards, R. Lawrence (University of Minnesota. Department of Geology and Geophysics)

Date:	2006
Abstract:	Abrupt decreases of the Atlantic meridional overturning circulation (MOC) during the Late Pleistocene have been directly linked to catastrophic discharges of glacimarine freshwater, triggering disruption of northward marine heat transport and causing global climate changes. Here we provide measurements of excess sedimentary ²³¹Pa/²³⁰Th from a high-accumulation sediment drift deposit in the NE Atlantic that record a sequence of sudden variations in the rate of MOC, associated deep ocean ventilation and surface-ocean climatology. The data series reveal a sequential decrease in the MOC rate at ~18. 0 ka BP ago that coincides with only transient and localized freshwater inputs. This change represents a substantial, though not total, cessation in MOC that predates the major Heinrich (H1) meltwater event by at least 1,200 years. These results highlight the potential of targeted freshwater perturbations in promoting substantial MOC changes without a direct linking with catastrophic freshwater surges.
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Global climate changes ; Late Pleistocene ; Meridional overturning circulation ; MOC
Published in:	Geophysical research letters, Vol. 33, Issue 16 (2006) , 5 p., ISSN 0094-8276

DOI: 10.1029/2006GL026239

5 p, 370.2 KB

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