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

TitleAmplitude and timing of temperature and salinity variability in the subpolar North Atlantic over the past 10 k.y.
Publication TypeJournal Article
Year of Publication2007
AuthorsCame, RE, Oppo, DW, McManus, JF
JournalGeology
Volume35
Issue4
Pagination315-318
KeywordsBjörn Drift, Mg/Ca, Neogloboquadrina pachyderma dextral, Ocean Drilling Program Site 984, paleotemperature
Abstract

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.

DOI10.1130/G23455A.1