Amplitude and timing of temperature and salinity variability in the subpolar North Atlantic over the past 10 k.y

Paired planktic foraminiferal δ18O and Mg/Ca data reveal trends of increasing temperatures (∼3°C) and salinities in the subpolar North Atlantic over the course of the Holocene, which were punctuated by abrupt events. The trends likely reflect an insolation-forced northward retreat of the boundary be...

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Bibliographic Details
Published in:Geology (Boulder) 2007-04, Vol.35 (4), p.315-318
Main Authors: Came, Rosemarie E, Oppo, Delia W, McManus, Jerry F
Format: Article
Language:English
Subjects:
absolute age
alkaline earth metals
Atlantic Ocean
C-14
calcium
carbon
Cenozoic
chemical ratios
climate change
cooling
cores
dates
Deepwater drilling
Foraminifera
Geochemistry
Geology
glacial environment
glaciomarine environment
Globigerinacea
Holocene
Invertebrata
isotope ratios
isotopes
Leg 162
magnesium
marine environment
marine sediments
metals
Mg/Ca
microfossils
Neogloboquadrina
Neogloboquadrina pachyderma
North Atlantic
O-18/O-16
Ocean Drilling Program
Oceanography
Oceans
ODP Site 984
oxygen
paleo-oceanography
paleocirculation
paleoclimatology
paleoecology
paleosalinity
paleotemperature
planktonic taxa
Protista
Quaternary
Quaternary geology
radioactive isotopes
Rotaliina
Salt
secular variations
sediments
stable isotopes
Temperature
upper Quaternary
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Summary:Paired planktic foraminiferal δ18O and Mg/Ca data reveal trends of increasing temperatures (∼3°C) and salinities in the subpolar North Atlantic over the course of the Holocene, which were punctuated by abrupt events. The trends likely reflect an insolation-forced northward retreat of the boundary between polar and North Atlantic subsurface waters. The superimposed variability does not appear to be periodic, but tends to recur within a broad millennial band. The records provide convincing evidence of open-ocean cooling (nearly 2°C) and freshening during the 8.2 ka event, and suggest similar conditions at 9.3 ka. However, the two largest temperature oscillations in our record (∼2°C) occurred during the past 4 k.y., suggesting a recent increase in temperature variability relative to the mid-Holocene, perhaps in response to neoglaciation, which began at about this time.
ISSN:0091-7613
1943-2682
DOI:10.1130/G23455A.1