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Pleistocene iceberg dynamics on the west Svalbard margin: evidence from bathymetric and sub-bottom profiler data

Pleistocene iceberg dynamics on the west Svalbard margin: evidence from bathymetric and sub-bottom profiler data
Pleistocene iceberg dynamics on the west Svalbard margin: evidence from bathymetric and sub-bottom profiler data
Large icebergs leave evidence of their drift via ploughing of the seabed, thereby providing a geological record of episodes of calving from thick ice sheets. We interpret large-scale curvilinear depressions on the western Svalbard margin as ploughmarks produced by the keels of icebergs that grounded on the seafloor as they drifted through this area. Iceberg ploughmarks were identified at modern water depths between 300 m and 1000 m and in two distinct stratigraphic units. Combining data from sediment cores with seismic stratigraphy from sub-bottom profiler data suggests that the ploughmarks developed in two phases: (1) during Marine Isotope Stage (MIS) 6; and (2) during MIS 2, indicating the presence of large drifting icebergs on the western Svalbard margin during both the Late Saalian and Late Weichselian glaciations. Sediment-core data along the western Svalbard margin indicate a sharp increase in mass-transported sediments dated at 23.7 ± 0.2 ka, consistent with the MIS 2 age of the younger iceberg-ploughed surface. The ploughmarks are oriented in two main directions: SW-NE and S-N. S-N oriented ploughmarks, which shallow to the north, indicate iceberg drift from the south with a SW–NE component marking the zone of splitting of the West Spitsbergen Current (WSC) into the Yermak Slope Current (YSC) and North Spitsbergen Current (NSC). Large MIS 6 and MIS 2 icebergs most likely had an Arctic Ocean source. We suggest that these icebergs probably left the Arctic Ocean southward through Fram Strait and circulated within the Norwegian-Greenland Sea before being transported northwards along the Svalbard margin by the WSC. An additional likely source of icebergs to the western Svalbard margin during MIS 2 was the ice-sheet terminating in the western Barents Sea, from which icebergs drifted northward.
0277-3791
30-44
Zhao, Fang
016d32e9-a5cb-4539-86f2-14430259c2d9
Minshull, Timothy A.
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Crocker, Anya J.
1215fbdd-ad43-408a-bd79-c54c6847e68c
Dowdeswell, Julian A.
106dce8d-e831-4407-b65d-575452be2cb8
Wu, Shiguo
69147547-c51a-4c89-ae14-45b8b0b1defa
Soryal, Simon M.
adbf15f8-4ead-4157-9db2-0c722b45ce88
Zhao, Fang
016d32e9-a5cb-4539-86f2-14430259c2d9
Minshull, Timothy A.
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Crocker, Anya J.
1215fbdd-ad43-408a-bd79-c54c6847e68c
Dowdeswell, Julian A.
106dce8d-e831-4407-b65d-575452be2cb8
Wu, Shiguo
69147547-c51a-4c89-ae14-45b8b0b1defa
Soryal, Simon M.
adbf15f8-4ead-4157-9db2-0c722b45ce88

Zhao, Fang, Minshull, Timothy A., Crocker, Anya J., Dowdeswell, Julian A., Wu, Shiguo and Soryal, Simon M. (2017) Pleistocene iceberg dynamics on the west Svalbard margin: evidence from bathymetric and sub-bottom profiler data. Quaternary Science Reviews, 161, 30-44. (doi:10.1016/j.quascirev.2017.01.019).

Record type: Article

Abstract

Large icebergs leave evidence of their drift via ploughing of the seabed, thereby providing a geological record of episodes of calving from thick ice sheets. We interpret large-scale curvilinear depressions on the western Svalbard margin as ploughmarks produced by the keels of icebergs that grounded on the seafloor as they drifted through this area. Iceberg ploughmarks were identified at modern water depths between 300 m and 1000 m and in two distinct stratigraphic units. Combining data from sediment cores with seismic stratigraphy from sub-bottom profiler data suggests that the ploughmarks developed in two phases: (1) during Marine Isotope Stage (MIS) 6; and (2) during MIS 2, indicating the presence of large drifting icebergs on the western Svalbard margin during both the Late Saalian and Late Weichselian glaciations. Sediment-core data along the western Svalbard margin indicate a sharp increase in mass-transported sediments dated at 23.7 ± 0.2 ka, consistent with the MIS 2 age of the younger iceberg-ploughed surface. The ploughmarks are oriented in two main directions: SW-NE and S-N. S-N oriented ploughmarks, which shallow to the north, indicate iceberg drift from the south with a SW–NE component marking the zone of splitting of the West Spitsbergen Current (WSC) into the Yermak Slope Current (YSC) and North Spitsbergen Current (NSC). Large MIS 6 and MIS 2 icebergs most likely had an Arctic Ocean source. We suggest that these icebergs probably left the Arctic Ocean southward through Fram Strait and circulated within the Norwegian-Greenland Sea before being transported northwards along the Svalbard margin by the WSC. An additional likely source of icebergs to the western Svalbard margin during MIS 2 was the ice-sheet terminating in the western Barents Sea, from which icebergs drifted northward.

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More information

Accepted/In Press date: 25 January 2017
e-pub ahead of print date: 21 February 2017
Published date: 1 April 2017
Organisations: Geology & Geophysics, Ocean and Earth Science, Paleooceanography & Palaeoclimate

Identifiers

Local EPrints ID: 405340
URI: http://eprints.soton.ac.uk/id/eprint/405340
ISSN: 0277-3791
PURE UUID: 2ad8003c-468b-48a6-855d-5214b484d179
ORCID for Timothy A. Minshull: ORCID iD orcid.org/0000-0002-8202-1379
ORCID for Anya J. Crocker: ORCID iD orcid.org/0000-0001-9561-5750

Catalogue record

Date deposited: 01 Feb 2017 11:33
Last modified: 02 Apr 2022 04:02

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Contributors

Author: Fang Zhao
Author: Anya J. Crocker ORCID iD
Author: Julian A. Dowdeswell
Author: Shiguo Wu
Author: Simon M. Soryal

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