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Geophysical Research Abstracts
Vol. 14, EGU2012-5919, 2012
EGU General Assembly 2012
© Author(s) 2012
Deglacial subsurface injections of Atlantic water into the Nordic Seas and
its effect on interglacial climate development
H.A. Bauch
Mainz Academy c/o GEOMAR, Kiel, Germany (hbauch@geomar.de)
Using multi-proxy sediment records from two distant sites in the North Atlantic and the Nordic Seas, surface
and bottom water changes were investigated over the past 135 ka with special emphasis on the last and present
interglacial (Eemian and Holocene). The two interglacials exhibit a very similar developing structure during each
preceding deglaciation (TI and TII) in the Nordic Seas by showing a pronounced cold–warm–cold variability. Like
TI, also TII experienced a Younger-Dryas-like cold reversal (YDII), a preceding Bølling/Allerød-like (B/AII) and a
H-event (H11). But unlike TI, the cold events during TII were associated with intermittent invasions of an Atlantic
faunal component (Beella megastoma) which underscores a northward penetration of mid-latitude waters at the
subsurface leaving a vertical water mass structure in the North which differed from that of TI. Very likely, this
difference also affected the subsequent oceanic development because the main interglacials that followed not only
reveal a regional antiphase, intra-interglacial behavior of peak ocean warmth between each other, they also verify
strong contrasts in surface ocean hydrography. Moreover, colder Eemian than Holocene temperatures are noted in
the Nordic Seas, and vice versa in the North Atlantic. A reduced intensity of Atlantic ocean heat transfer to the
Arctic is therefore inferred for the Eemian, thus arguing for a reassessment of current Arctic paleoclimate models
and a better reconciliation with empirical field data.