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Jo Brendryen, University of Bergen (Norway)
Haflidi Haflidason, University of Bergen (Norway)
Hans Petter Sejrup, University of Bergen (Norway)
Kristin Grasmo, University of Bergen (Norway)
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The newly developed XRF core scanning technique has proofed to provide a new possibility to assess the chemical properties of marine sediment cores at a hitherto unprecedented time resolution. This technique has been applied to sediments from the 50-125 ka interval of core MD99-2289, raised from 1262 m water depth in the SE Nordic Seas. The sediment core was measured at resolution down to 200 m for a suite of chemical elements by the ITRAX core scanner. From comparing the data with other environmental proxies it is suggested that the down core chemical profiles contain detailed information of past oceanic conditions and sedimentary environments. A comparison to the NGRIP ice core shows further high degree of similarity between events seen in the indicators of biogenic productivity like calcium and strontium and indicators of terrigeneous material like iron from MD99-2289 and events seen in the δ18O record of the ice core. It is believed that the high grade of co-variation between the records arises from the close connection between northern Greenland temperature and oceanic conditions in the SE Nordic seas, most probably as a function of the influx of Atlantic water to the Nordic seas across the Iceland-Scotland ridge and related positions of the oceanic front systems. Coarse tephra grains (>150 m), inferred to be ice rafted and geochemically linked to the Jan Mayen volcanic system, is found in the core at a depth corresponding to the end of the last interglacial. The deposition of the ice rafted Jan Mayen tephra is documenting direct influence of cold southward flowing water masses over the coring site and is coincident with an abrupt drop in Ca and Sr values and a related increase in Fe values. This is providing further support of an interpretation that Ca and Sr values are related to degree of Atlantic water influx and oceanic front positions. The data suggest that correlation of events at least down to centennial scale is possible. Several discrete tephra layers are recorded between 50 and 125 ka in MD99-2289 If these tephra layers are found in the ice core, a direct validating of the correlation by means of stratigraphical marker horizons will be possible. This will also quantify possible leads and lags between the records.
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