Premium
Accelerated drawdown of meridional overturning in the late‐glacial Atlantic triggered by transient pre‐H event freshwater perturbation
Author(s) -
Hall I. R.,
Moran S. B.,
Zahn R.,
Knutz P. C.,
Shen C.C.,
Edwards R. L.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl026239
Subject(s) - geology , thermohaline circulation , meltwater , shutdown of thermohaline circulation , north atlantic deep water , glacial period , climatology , perturbation (astronomy) , oceanography , ocean current , climate change , paleontology , physics , quantum mechanics
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 231 Pa/ 230 Th 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.