1-s2.0-S0277379113003430-main.pdf (10.79 MB)
Late Quaternary ice flow in a West Greenland fjord and cross-shelf trough system: submarine landforms from Rink Isbrae to Uummannaq shelf and slope
journal contribution
posted on 2015-06-12, 13:30 authored by Julian A. Dowdeswell, K.A. Hogan, Colm O Cofaigh, E.M.G. Fugelli, Jeffrey EvansJeffrey Evans, R. NoormetsSea-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 400km-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, 300km to the south. Ice retreat had begun by 14.8cal.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. © 2013 The Authors.
Funding
This research was funded by UK Natural Environment Research Council [grant number NE/D001951/1].
History
School
- Social Sciences
Department
- Geography and Environment
Published in
Quaternary Science ReviewsVolume
92Pages
292 - 309Citation
DOWDESWELL, J.A. ... et al, 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, pp. 292 - 309.Publisher
Elsevier Ltd / © The AuthorsVersion
- VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution 3.0 Unported (CC BY 3.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/by/3.0/Publication date
2014Notes
This is an Open Access article published by Elsevier and distributed under a Creative Commons Attribution Licence CC-BY 3.0 http://creativecommons.org/licenses/by/3.0/ which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ISSN
0277-3791Publisher version
Language
- en