Ice dynamics and sediment movement : last glacial cycle, Clyde Basin, Scotland
Finlayson, Andrew G.. 2012 Ice dynamics and sediment movement : last glacial cycle, Clyde Basin, Scotland. Journal of Glaciology, 58 (209). 487-500. 10.3189/2012JoG11J207Before downloading, please read NORA policies.
The nature and behaviour of sediment beneath glaciers influences how they flow and respond to changing environmental conditions. The difficulty of accessing the bed of current glaciers is a key constraint to studying the processes involved. This paper explores an alternative approach by relating sediments under the beds of former mid-latitude ice sheets to changing ice behaviour during a glacial cycle. The paper focuses on the partly marine-based Pleistocene British-Irish ice sheet in the Clyde basin, Scotland. A three-dimensional computation of subsurface glacial sediment distribution is derived from 1260 borehole logs. Sediment distribution is linked to an empirically based reconstruction of ice-sheet evolution, permitting identification of distinctive phases of sedimentation. Maximum sediment mobilization and till deposition (∼0.04 m a-1) occurred during ice advance into the basin from adjacent uplands. Transport distances were generally short. Subglacial processes were influenced locally by the relative stiffness of pre-existing sediments, the permeability of the sub-till lithology, and topography; the resulting mean till thickness is 7.7 m with a high standard deviation of 7.0 m. In places, focused till deposition sealed pre-existing permeable substrates, promoting lower effective pressures. Sediment remobilization by meltwater was a key process as ice margins retreated through the basin.
|Item Type:||Publication - Article|
|Digital Object Identifier (DOI):||10.3189/2012JoG11J207|
|Programmes:||BGS Programmes 2010 > Geology and Landscape (Scotland)|
|Date made live:||23 Jul 2012 10:57|
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