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Title: The palaeoceanography and glacial history of the Greenland Sea and Spitsbergen Ice Cap over the last 200ka
Author: Lloyd, Jeremy
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1994
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Piston cores from the continental slope of Spitsbergen were analysed using micropalaeontological, stable isotope and sedimentological techniques. The attempted to determine the palaeoceanographic history of the Norwegian-Greenland Sea, and the glacial history of the Spitsbergen ice cap over the last 200ka. The chronostratigraphy of the cores was determined using stable oxygen isotope analysis of planktic foraminifera. These records were correlated to a composite benthic foraminiferal δ18 O stratigraphy from the Norwegian Sea (Duplessy et al., 1988), as well as to other radiometrically dated records from the Norwegian-Greenland Sea to produce an age model. X-ray photographs were used to assess the ice rafted detrital (IRD) content of the cores, dropstones were counted from these x-rays. IRD content was used as a measure of calving rate from the outlet glaciers of the Spitsbergen ice cap. From these counts and the δ18O record a model of relative advance and retreat of the Spitsbergen ice cap was produced. It was found that moisture supply was the over riding factor controlling dropstone input to the Spitsbergen margin. Periods of high moisture supply led to rapid ice advance and hence high calving rate producing peaks in IRD. Peak IRD events were found during interstadial periods, such as substage 5c, as well as during glacial periods when ice was at the shelf edge, and during deglacial periods. Absolute abundance counts of foraminifera suggest glacial periods had a much higher productivity than interglacial periods. This strongly suggests the Spitsbergen margin was at least seasonally ice free during glacial periods. Melting events were recognised from the δ18O record of planktic and benthic foraminifera. The influx of North Atlantic surface waters during deglaciation has been identified from the δ18O record and the faunal assemblages. The initial influx of North Atlantic water during the last deglaciation took place at about 12.3ka, disappeared at 12ka, was present again from 10.5 to 10.3ka, and then from 10ka onwards.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available