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Glacial and submarine processes on the shelf margin of the Disko Bay trough Mouth Fan

Hofmann, Julia C.; Knutz, Paul C.; Kjær, Kurt H.; Nielsen, Tove; Ó Cofaigh, Colm

Glacial and submarine processes on the shelf margin of the Disko Bay trough Mouth Fan Thumbnail


Authors

Julia C. Hofmann

Paul C. Knutz

Kurt H. Kjær

Tove Nielsen



Abstract

Fast-flowing ice streams and outlet glaciers exert a major control on glacial discharge from contemporary and past ice sheets. Improving our understanding of the extent and dynamic behaviour of palaeo-ice streams is crucial for predictions of how the chryosphere will respond to climate warming and the associated implications for global sea level. This paper presents results from two 3D-seismic surveys located on the continental shelf adjoining the Disko Bay Trough Mouth Fan (TMF), one of the largest glacial outlet systems in Greenland. Located at the seaward terminus of the c. 370 km long cross-shelf Disko Trough, the Disko Bay TMF was generated by highly efficient subglacial sediment delivery onto the continental slope during repeated ice stream advances. A variety of submarine glacial landform assemblages are recognised on the seabed reflecting past ice stream activity. The 3D-seismic study covers the shallow banks located north and south of the Disko Trough and sheds focus on the seabed and the uppermost stratigraphic interval associated with the late Pleistocene development. The buried section (probably of Saalian age) contains a prominent grounding-zone wedge (GZW) in the northern and low-angle progradational packages in the southern area, indicating a period of major glacial advances to the shelf margin. Subsequently, the outer margin was influenced by glacimarine sedimentation, localized shelf-edge ice advances and sediment transport by contour currents that possibly began in the last interglacial period (Eemian). During the last (de)glaciation, the northern bank appears to have been covered by passive ice leaving a field of dead-ice deposits. In contrast, multiple sets of terminal moraine ridges observed on the southern bank suggest a slow retreat of active, grounded ice from the Last Glacial Maximum position on the outer shelf. Isostatic and tectonic influences on relative sea level may have played a role in generating the divergent glacial configurations of the northern and southern bank areas.

Citation

Hofmann, J. C., Knutz, P. C., Kjær, K. H., Nielsen, T., & Ó Cofaigh, C. (2018). Glacial and submarine processes on the shelf margin of the Disko Bay trough Mouth Fan. Marine Geology, 402, 33-50. https://doi.org/10.1016/j.margeo.2017.12.001

Journal Article Type Article
Acceptance Date Dec 1, 2017
Online Publication Date Dec 5, 2017
Publication Date Aug 1, 2018
Deposit Date Jan 3, 2018
Publicly Available Date Mar 28, 2024
Journal Marine Geology
Print ISSN 0025-3227
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 402
Pages 33-50
DOI https://doi.org/10.1016/j.margeo.2017.12.001

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