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Title: Soil geochemistry applied as proxy for till geochemistry in the northern sector of the Irish Ice Sheet : provenance, dispersal patterns and drift prospecting
Author: Dempster, Michael
ISNI:       0000 0004 5990 0089
Awarding Body: Ulster University
Current Institution: Ulster University
Date of Award: 2014
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Abstract:
The Irish Ice Sheet has been an active area of research since the mid 19th century. Traditional approaches to reconstructing the Irish Ice Sheet have used the landform and sediment record to define its extent and formulate models of its geometry through the Pleistocene. Subglacial bedforms dominate the landform record and till is the dominant sediment. The bedforms demonstrate a complex ice flow history, however recent research has indicated that ice flow directions interpreted from subglacial bedform geomorphology could be misleading. It is therefore appropriate to consider other methods of investigating ice flow patterns that are independent of geomorphology. As the bedforms are primarily composed of till, an alternative approach to determining flow directions is to establish the provenance of the till using geochemistry. High density regional soil geochemical data sets comprising> 1 0,000 sample points are available for the north of Ireland. This thesis applies a multi variate statistical approach to the soil geochemistry to establish till provenance in the northern sector of the Irish Ice Sheet. Till provenance is determined for the entire region and also investigated in a range of palaeoglaciological contexts. Results are compared to recent models of flow history for the Irish Ice Sheet. Till provenance is also applied to determine the degree of glacial dispersal of gold mineralisation from known host regions in the north of Ireland. The thesis demonstrates that till in this sector of the Irish Ice Sheet shows a very strong geochemical link to local bedrock composition, with sharp geochemical transitions observed at lithological boundaries. However, subglacial transport and clear dispersal patterns are detected particularly at flow set scale in a range of palaeoglaciological contexts. Geochemical evidence is found for flow directions for each of the major phases of the history of the last Irish Ice Sheet and this evidence compliments existing models. No unequivocal glacial dispersal patterns are detected for gold, though the prospectivity of currently unexplored areas is highlighted. The research demonstrates that soil geochemistry makes a significant contribution to Quaternary research in Ireland which has not been previously recognised.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.701053  DOI: Not available
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