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Sedimentation associated with Antarctic Peninsula ice shelves: implications for palaeoenvironmental reconstructions of glacimarine sediments

Evans, J.; Pudsey, C.J.. 2002 Sedimentation associated with Antarctic Peninsula ice shelves: implications for palaeoenvironmental reconstructions of glacimarine sediments. Journal of the Geological Society, 159 (3). 233-237. 10.1144/0016-764901-125

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Abstract/Summary

Recent disintegration of a number of Antarctic Peninsula ice shelves has given us a unique opportunity to investigate sub-ice-shelf sediments. We characterize three sediment facies associations of two Antarctic Peninsula ice shelves (Larsen-A and Larsen Inlet). Subglacial facies consist mainly of basal till (diamicton) with high shear strengths deposited under a grounded ice sheet. Progressive upward decrease in shear strength reflects a gradual decrease in the confining vertical effective pressure of grounded ice during till deposition. Proximal ice-shell glacimarine facies (diamicton, gravel-rich and sand-rich facies, gravelly mud, dropstone Mud and sands muds) ere deposited by sub-ice-shelf rain out, bottom current activity and sediment gravity flows following decoupling of grounded ice from the sea-floor, Distal, he-shell glacimarine and/or open marine facies comprise terrigenous and diatom-bearing bioturbated muds and gravelly muds that contain limited ice-rafted debris these accumulated after recession of the grounding line to the coast, with coarse-grained surface sediments possible documenting most recent ice-shelf break-up. Antarctic Peninsula ice-shelf sediments are more heterogeneous than ice-shelf facies deposited else's here in Antarctica. Cold. polar Antarctic ice shelves can be differentiated from temperate and sub-polar marine-terminated glacial sedimentary systems by the dominance of coarse-grained proximal. ice-shelf glacimarine facies and an absence of subaqueous outwash/meltwater sediment facies.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1144/0016-764901-125
Programmes: BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Signals in Antarctica of Past Global Changes
ISSN: 0016-7649
Additional Keywords: Antarctic Peninsula, ice shelves, sediment facies, facies associations, deglaciation
NORA Subject Terms: Glaciology
Earth Sciences
Date made live: 15 Nov 2011 10:51
URI: http://nora.nerc.ac.uk/id/eprint/13325

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