Rapid variations in climate through glacial periods have been associated with changes in ocean conditions. Modelling iceberg flow and melt is critical to evaluating their role in perturbing the state of oceans during glacial periods and subsequent deglaciation. This thesis aims to quantify the spatial and temporal history of icebergs flow, melt and sedimentation after release from the Eurasian Ice Sheet during the last deglaciation. The research structure required to meet this aim is in three steps. First, results from a numerical ice sheet model were processed in order to use them as input to an iceberg flow model. Other model inputs, such as topography and ocean and climate forcing fields, were also collated and input. Second, an iceberg model was compiled so that iceberg melt and sedimentation could be evaluated in the late glacial Nordic seas. Third, knowledge of the marine sedimentation record was built in order to compare with model results. This comparison allowed a number of literature-based hypotheses to be tested. This thesis has revealed the following results. The model showed that Eurasian icebergs may only be delivered to the North Atlantic under glacial ocean and atmospheric conditions. Under conditions similar to today, icebergs are restricted to the northern waters of the Nordic seas. The model also revealed that iceberg meltwater does not have a simple-distance-decay relationship. Instead, the pattern of meltwater release was found to be influenced by iceberg convergence zones; a consequence of the iceberg response to atmospheric and oceanic forcing. The model results also demonstrated that the locations of iceberg meltwater did not always coincide with modelled IRD. Consequently, the absence of IRD in the marine sedimentary record should not necessarily be interpreted as an indicator of absence of former icebergs. Models of the ice-ocean-atmosphere currently treat iceberg meltwater input in a simple way. The results presented here may be used in further numerical investigations of the processes responsible for rapid climate change in the last deglaciation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:573926 |
| Date | January 2004 |
| Creators | De'ath, Rosalyn M. |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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