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| Titel |
Stepwise transition from deglacial/Early Holocene to modern-like conditions in the eastern Fram Strait, sub-Arctic north, inferred from planktic foraminifer fauna and sea surface temperatures |
| VerfasserIn |
K. Werner, R. F. Spielhagen, E. Kandiano, H. C. Hass |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250062661
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| Zusammenfassung |
| The heat content of the Arctic Ocean is mainly controlled by the inflow of north-heading
warm and saline Atlantic Water through eastern Fram Strait. The eastern Fram Strait is
therefore ice-free all year, opposite to its perennially ice-covered western part where large
amounts of Arctic sea ice are exported year-round to the Nordic Seas. The Early and
Mid-Holocene phases (ca 12 to 5 cal ka BP) in the (sub-)Arctic have been especially marked
not only by high summer insolation but also by rising sea level and the final disintegration of
large ice sheets that had been established during the preceding glacial phase. Two sediment
cores with multidecadal resolution from the Western Svalbard margin have been investigated
for its planktic foraminiferal distribution, sea surface temperatures, planktic and
benthic stable isotope ratios, and lithological parameters to derive information on the
Holocene variability of the heat transport to the Arctic Ocean and related fluctuations of
the marginal ice zone in the eastern Fram Strait. Planktic foraminifer fauna and
a summer sea surface temperature reconstruction based on the modern analogue
technique imply a stepwise transition from deglacial/Early Holocene to modern-like
conditions in the eastern Fram Strait. Repeated short-term advances of the sea ice margin
accompanied the generally strong heat transport to the Arctic Ocean during the Early to
Mid-Holocene. Consistent with the decreasing solar insolation, cooler (sub-)surface
conditions established after ca 5 cal ka BP most likely related to both a weakening of the
Atlantic Water inflow and strong export of Arctic sea ice through Fram Strait. The
Late Holocene Neoglacial phase was characterized by high contents of ice-rafted
material and dominance of the cold water-indicating planktic foraminifer species
Neogloboquadrina pachyderma. Cool Late Holocene conditions are reversed by a
strong warming event likely caused by a significant strengthening of Atlantic heat
advection to the Arctic during the present, anthropogenically influenced period. |
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