J.A. Dowdeswell
Late Quaternary ice flow in a West Greenland fjord and cross-shelf trough system: submarine landforms from Rink Isbrae to Uummannaq shelf and slope
Dowdeswell, J.A.; Hogan, K.A.; Ó Cofaigh, C.; Fugelli, E.M.G.; Evans, J.; Noormets, R.
Authors
K.A. Hogan
Professor Colm O'Cofaigh colm.ocofaigh@durham.ac.uk
Professor
E.M.G. Fugelli
J. Evans
R. Noormets
Abstract
Sea-floor landforms and acoustic-stratigraphic records allow interpretation of the past form and flow of a westward-draining ice stream of the Greenland Ice Sheet, Rink Isbrae. The Late Pliocene–Pleistocene glacial package is several hundred metres thick and down-laps onto an upper Miocene horizon. Several acoustic facies are mapped from sub-bottom profiler records of the 400 km-long Uummannaq fjord-shelf-slope system. An acoustically stratified facies covers much of the fjord and trough floor, interpreted as glacimarine sediment from rain-out of fine-grained debris in turbid meltwater. Beneath this facies is a semi-transparent deformation-till unit, which includes buried streamlined landforms. Landform distribution in the Uummannaq system is used to reconstruct past ice extent and flow directions. The presence of streamlined landforms (mega-scale glacial lineations, drumlins, crag-and-tails) shows that an ice stream advanced through the fjord system to fill Uummannaq Trough, reaching the shelf edge at the Last Glacial Maximum. Beyond the trough there is a major fan built mainly of glacigenic debris flows. Turbidity-current channels were not observed on Uummannaq Fan, contrasting with well-developed channels on Disko Fan, 300 km to the south. Ice retreat had begun by 14.8 cal. ka ago. Grounding-zone wedges (GZW) in Uummannaq Trough imply that retreat was episodic, punctuated by several still-stands. Ice retreat between GZWs may have been relatively rapid. There is little sedimentary evidence for still-stands in the inner fjords, except for a major moraine ridge marking a Little Ice Age maximum position. On the shallow banks either side of Uummannaq Trough, iceberg ploughing has reworked any morphological evidence of earlier ice-sheet activity.
Citation
Dowdeswell, J., Hogan, K., Ó Cofaigh, C., Fugelli, E., Evans, J., & Noormets, R. (2014). Late Quaternary ice flow in a West Greenland fjord and cross-shelf trough system: submarine landforms from Rink Isbrae to Uummannaq shelf and slope. Quaternary Science Reviews, 92, 292-309. https://doi.org/10.1016/j.quascirev.2013.09.007
Journal Article Type | Article |
---|---|
Acceptance Date | Sep 12, 2013 |
Online Publication Date | Nov 1, 2013 |
Publication Date | May 15, 2014 |
Deposit Date | May 15, 2014 |
Publicly Available Date | Dec 9, 2014 |
Journal | Quaternary Science Reviews |
Print ISSN | 0277-3791 |
Electronic ISSN | 1873-457X |
Publisher | Elsevier |
Peer Reviewed | Peer Reviewed |
Volume | 92 |
Pages | 292-309 |
DOI | https://doi.org/10.1016/j.quascirev.2013.09.007 |
Keywords | Arctic, Ice flow, Ice stream, Late Quaternary, Submarine landforms, Trough-mouth fan, West Greenland. |
Public URL | https://durham-repository.worktribe.com/output/1465108 |
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Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/
Copyright Statement
© 2013 The Authors. Published by Elsevier Ltd. Open access under CC BY license.
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