Accelerated drawdown of meridional overturning in the late-glacial Atlantic triggered by transient pre-H event freshwater perturbation

I.R. Hall, S.B. Moran, R. Zahn, P.C. Knutz, C.-C. Shen, R.L. Edwards

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

84 Citationer (Scopus)

Abstrakt

[1] 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.

OriginalsprogEngelsk
ArtikelnummerL16616
Antal sider5
TidsskriftGeophysical Research Letters
Vol/bind33
Udgave nummer16
DOI
StatusUdgivet - 1 aug. 2006

Programområde

  • Programområde 5: Natur og klima

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