Publication Date:
2015-12-19
Description:
In this study, we present a unique high-resolution Holocene record of oceanographic and climatic change based on analyses of diatom assemblages combined with biomarker data from a sediment core collected from the Vega Drift, eastern Antarctic Peninsula (EAP). These data add to the climate framework already established by high-resolution marine sedimentary records from the Palmer Deep, western Antarctic Peninsula (WAP). Heavy sea ice conditions and reduced primary productivity were observed prior to 7.4 ka BP in relation with the proximity of the glacial ice melt and calving. Subsequent Holocene oceanographic conditions were controlled by the interactions between the Westerlies-Antarctic Circumpolar Current (ACC)-Weddell Gyre dynamics. A warm period characterized by short seasonal sea ice duration associated with a southern shift of both ACC and Westerlies field persisted until 5 ka BP. This warm episode was then followed by climate deterioration during the Mid-to-late Holocene (5 to 1.9 ka BP) with a gradual increase in annual sea ice duration triggered by the expansion of the Weddell Gyre and a strong oceanic connection from the EAP to the WAP. Increase of benthic diatom species during this period was indicative of more summer/autumn storms, which was consistent with changes in synoptic atmospheric circulation and the establishment of low-to-high latitudes teleconnections. Finally, the multi-centennial scale variability of the Weddell Gyre intensity and storm frequency during the Late Holocene appeared to be associated with the increased El Niño-Southern Oscillation (ENSO) frequency.
Print ISSN:
0883-8305
Electronic ISSN:
1944-9186
Topics:
Geosciences
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