Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland

Louise Callard; Colm  Ó Cofaigh; S. Benetti; Richard Chiverrell; Katrien J J  Van Landeghem; Margot Saher; Stephen J Livingstone; Chris D Clark; David Small; Derek  Fabel; Steven G Moreton

doi:10.1016/j.margeo.2019.106087

Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland

Louise Callard
, Colm Ó Cofaigh
, S. Benetti
, Richard Chiverrell
, Katrien J J Van Landeghem
, Margot Saher
, Stephen J Livingstone
, Chris D Clark
, David Small
, Derek Fabel
, Steven G Moreton

Research output: Contribution to journal › Article › peer-review

22 Citations (Scopus)

85 Downloads (Pure)

Abstract

During the Last Glacial Maximum, the British-Irish Ice Sheet extended across the continental shelf offshore of Galway Bay, western Ireland, and reached a maximum westward extent on the Porcupine Bank. New marine geophysical data, sediment cores and radiocarbon dates are used to constrain the style and timing of ice-sheet retreat across the mid to inner-shelf. Radiocarbon dated shell fragments in subglacial till on the mid-shelf constrains ice advance to after 26.4 ka BP. Initial retreat was underway before 24.4 ka BP, significantly earlier than previous reconstructions. Grounding-line retreat was accompanied by stillstands and/or localised readvances of the grounding-line. A large composite Mid-Shelf Grounding Zone Complex marks a major grounding-line position, with the ice grounded and the margin oscillating at this position by, and probably after, 23 ka BP. The continental shelf was ice-free by 17.1 cal. ka BP, but the ice sheet may have retained a marine margin until c. 15.3 ka BP. Retreat occurred in a glacimarine setting and the ice sheet was fringed by a floating ice-shelf. Collectively, this evidence indicates a dynamic and oscillatory marine-terminating ice sheet offshore of western Ireland during the last deglaciation.

Original language	English
Article number	106087
Journal	Marine Geology
Volume	420
Early online date	26 Nov 2019
DOIs	https://doi.org/10.1016/j.margeo.2019.106087
Publication status	Published (in print/issue) - 1 Feb 2020

Bibliographical note

Funding Information:
This research was funded by the UK Natural Environment Research Council grant; BRITICE-CHRONO NE/J007196/1. The work was supported by the NERC Radiocarbon Facility (allocation numbers 1722.0613 and 1878.1014). Thanks are due to the staff at the NERC AMS Laboratory, East Kilbride for carbon isotope measurements. We thank the officers and crew of the RRS James Cook for their help with acquisition and the British Geological Survey and National Oceanography Centre for vibrocore and piston core collection during the cruise JC106. We also thank Kasper Weilbach, Riccardo Arosio, Catriona Purcell, Zoe Roseby, Kevin Schiele and Elke Hanenkamp for their scientific support on the JC106 leg 2 cruise. Finally, thanks to Hans Petter Sejrup and two anonymous reviewers who provided detailed comments and suggestions to improve the manuscript.

Funding Information:
This research was funded by the UK Natural Environment Research Council grant; BRITICE-CHRONO NE/J007196/1 . The work was supported by the NERC Radiocarbon Facility (allocation numbers 1722.0613 and 1878.1014 ). Thanks are due to the staff at the NERC AMS Laboratory, East Kilbride for carbon isotope measurements. We thank the officers and crew of the RRS James Cook for their help with acquisition and the British Geological Survey and National Oceanography Centre for vibrocore and piston core collection during the cruise JC106. We also thank Kasper Weilbach, Riccardo Arosio, Catriona Purcell, Zoe Roseby, Kevin Schiele and Elke Hanenkamp for their scientific support on the JC106 leg 2 cruise. Finally, thanks to Hans Petter Sejrup and two anonymous reviewers who provided detailed comments and suggestions to improve the manuscript. Appendix A

Publisher Copyright:
© 2019 Elsevier B.V.

Funding

Funding Information: This research was funded by the UK Natural Environment Research Council grant; BRITICE-CHRONO NE/J007196/1. The work was supported by the NERC Radiocarbon Facility (allocation numbers 1722.0613 and 1878.1014). Thanks are due to the staff at the NERC AMS Laboratory, East Kilbride for carbon isotope measurements. We thank the officers and crew of the RRS James Cook for their help with acquisition and the British Geological Survey and National Oceanography Centre for vibrocore and piston core collection during the cruise JC106. We also thank Kasper Weilbach, Riccardo Arosio, Catriona Purcell, Zoe Roseby, Kevin Schiele and Elke Hanenkamp for their scientific support on the JC106 leg 2 cruise. Finally, thanks to Hans Petter Sejrup and two anonymous reviewers who provided detailed comments and suggestions to improve the manuscript. Funding Information: This research was funded by the UK Natural Environment Research Council grant; BRITICE-CHRONO NE/J007196/1 . The work was supported by the NERC Radiocarbon Facility (allocation numbers 1722.0613 and 1878.1014 ). Thanks are due to the staff at the NERC AMS Laboratory, East Kilbride for carbon isotope measurements. We thank the officers and crew of the RRS James Cook for their help with acquisition and the British Geological Survey and National Oceanography Centre for vibrocore and piston core collection during the cruise JC106. We also thank Kasper Weilbach, Riccardo Arosio, Catriona Purcell, Zoe Roseby, Kevin Schiele and Elke Hanenkamp for their scientific support on the JC106 leg 2 cruise. Finally, thanks to Hans Petter Sejrup and two anonymous reviewers who provided detailed comments and suggestions to improve the manuscript. Appendix A Publisher Copyright: © 2019 Elsevier B.V.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 13 Climate Action

Keywords

British-Irish Ice Sheet
Continental shelf
Glacimarine
Grounding zone wedges
Ice shelf
Ice-sheet retreat
Last Glacial Maximum

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10.1016/j.margeo.2019.106087

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Callard, L., Ó Cofaigh, C., Benetti, S., Chiverrell, R., Van Landeghem, K. J. J., Saher, M., Livingstone, S. J., Clark, C. D., Small, D., Fabel, D., & Moreton, S. G. (2020). Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland. Marine Geology, 420, Article 106087. https://doi.org/10.1016/j.margeo.2019.106087

@article{038c4acdb03a47a8ba646960cb07cf10,

title = "Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland",

abstract = "During the Last Glacial Maximum, the British-Irish Ice Sheet extended across the continental shelf offshore of Galway Bay, western Ireland, and reached a maximum westward extent on the Porcupine Bank. New marine geophysical data, sediment cores and radiocarbon dates are used to constrain the style and timing of ice-sheet retreat across the mid to inner-shelf. Radiocarbon dated shell fragments in subglacial till on the mid-shelf constrains ice advance to after 26.4 ka BP. Initial retreat was underway before 24.4 ka BP, significantly earlier than previous reconstructions. Grounding-line retreat was accompanied by stillstands and/or localised readvances of the grounding-line. A large composite Mid-Shelf Grounding Zone Complex marks a major grounding-line position, with the ice grounded and the margin oscillating at this position by, and probably after, 23 ka BP. The continental shelf was ice-free by 17.1 cal. ka BP, but the ice sheet may have retained a marine margin until c. 15.3 ka BP. Retreat occurred in a glacimarine setting and the ice sheet was fringed by a floating ice-shelf. Collectively, this evidence indicates a dynamic and oscillatory marine-terminating ice sheet offshore of western Ireland during the last deglaciation.",

keywords = "British-Irish Ice Sheet, Continental shelf, Glacimarine, Grounding zone wedges, Ice shelf, Ice-sheet retreat, Last Glacial Maximum",

author = "Louise Callard and \{{\'O} Cofaigh\}, Colm and S. Benetti and Richard Chiverrell and \{Van Landeghem\}, \{Katrien J J\} and Margot Saher and Livingstone, \{Stephen J\} and Clark, \{Chris D\} and David Small and Derek Fabel and Moreton, \{Steven G\}",

note = "Funding Information: This research was funded by the UK Natural Environment Research Council grant; BRITICE-CHRONO NE/J007196/1. The work was supported by the NERC Radiocarbon Facility (allocation numbers 1722.0613 and 1878.1014). Thanks are due to the staff at the NERC AMS Laboratory, East Kilbride for carbon isotope measurements. We thank the officers and crew of the RRS James Cook for their help with acquisition and the British Geological Survey and National Oceanography Centre for vibrocore and piston core collection during the cruise JC106. We also thank Kasper Weilbach, Riccardo Arosio, Catriona Purcell, Zoe Roseby, Kevin Schiele and Elke Hanenkamp for their scientific support on the JC106 leg 2 cruise. Finally, thanks to Hans Petter Sejrup and two anonymous reviewers who provided detailed comments and suggestions to improve the manuscript. Funding Information: This research was funded by the UK Natural Environment Research Council grant; BRITICE-CHRONO NE/J007196/1 . The work was supported by the NERC Radiocarbon Facility (allocation numbers 1722.0613 and 1878.1014 ). Thanks are due to the staff at the NERC AMS Laboratory, East Kilbride for carbon isotope measurements. We thank the officers and crew of the RRS James Cook for their help with acquisition and the British Geological Survey and National Oceanography Centre for vibrocore and piston core collection during the cruise JC106. We also thank Kasper Weilbach, Riccardo Arosio, Catriona Purcell, Zoe Roseby, Kevin Schiele and Elke Hanenkamp for their scientific support on the JC106 leg 2 cruise. Finally, thanks to Hans Petter Sejrup and two anonymous reviewers who provided detailed comments and suggestions to improve the manuscript. Appendix A Publisher Copyright: {\textcopyright} 2019 Elsevier B.V.",

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doi = "10.1016/j.margeo.2019.106087",

language = "English",

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T1 - Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland

AU - Callard, Louise

AU - Ó Cofaigh, Colm

AU - Benetti, S.

AU - Chiverrell, Richard

AU - Van Landeghem, Katrien J J

AU - Saher, Margot

AU - Livingstone, Stephen J

AU - Clark, Chris D

AU - Small, David

AU - Fabel, Derek

AU - Moreton, Steven G

N1 - Funding Information: This research was funded by the UK Natural Environment Research Council grant; BRITICE-CHRONO NE/J007196/1. The work was supported by the NERC Radiocarbon Facility (allocation numbers 1722.0613 and 1878.1014). Thanks are due to the staff at the NERC AMS Laboratory, East Kilbride for carbon isotope measurements. We thank the officers and crew of the RRS James Cook for their help with acquisition and the British Geological Survey and National Oceanography Centre for vibrocore and piston core collection during the cruise JC106. We also thank Kasper Weilbach, Riccardo Arosio, Catriona Purcell, Zoe Roseby, Kevin Schiele and Elke Hanenkamp for their scientific support on the JC106 leg 2 cruise. Finally, thanks to Hans Petter Sejrup and two anonymous reviewers who provided detailed comments and suggestions to improve the manuscript. Funding Information: This research was funded by the UK Natural Environment Research Council grant; BRITICE-CHRONO NE/J007196/1 . The work was supported by the NERC Radiocarbon Facility (allocation numbers 1722.0613 and 1878.1014 ). Thanks are due to the staff at the NERC AMS Laboratory, East Kilbride for carbon isotope measurements. We thank the officers and crew of the RRS James Cook for their help with acquisition and the British Geological Survey and National Oceanography Centre for vibrocore and piston core collection during the cruise JC106. We also thank Kasper Weilbach, Riccardo Arosio, Catriona Purcell, Zoe Roseby, Kevin Schiele and Elke Hanenkamp for their scientific support on the JC106 leg 2 cruise. Finally, thanks to Hans Petter Sejrup and two anonymous reviewers who provided detailed comments and suggestions to improve the manuscript. Appendix A Publisher Copyright: © 2019 Elsevier B.V.

PY - 2020/2/1

Y1 - 2020/2/1

N2 - During the Last Glacial Maximum, the British-Irish Ice Sheet extended across the continental shelf offshore of Galway Bay, western Ireland, and reached a maximum westward extent on the Porcupine Bank. New marine geophysical data, sediment cores and radiocarbon dates are used to constrain the style and timing of ice-sheet retreat across the mid to inner-shelf. Radiocarbon dated shell fragments in subglacial till on the mid-shelf constrains ice advance to after 26.4 ka BP. Initial retreat was underway before 24.4 ka BP, significantly earlier than previous reconstructions. Grounding-line retreat was accompanied by stillstands and/or localised readvances of the grounding-line. A large composite Mid-Shelf Grounding Zone Complex marks a major grounding-line position, with the ice grounded and the margin oscillating at this position by, and probably after, 23 ka BP. The continental shelf was ice-free by 17.1 cal. ka BP, but the ice sheet may have retained a marine margin until c. 15.3 ka BP. Retreat occurred in a glacimarine setting and the ice sheet was fringed by a floating ice-shelf. Collectively, this evidence indicates a dynamic and oscillatory marine-terminating ice sheet offshore of western Ireland during the last deglaciation.

AB - During the Last Glacial Maximum, the British-Irish Ice Sheet extended across the continental shelf offshore of Galway Bay, western Ireland, and reached a maximum westward extent on the Porcupine Bank. New marine geophysical data, sediment cores and radiocarbon dates are used to constrain the style and timing of ice-sheet retreat across the mid to inner-shelf. Radiocarbon dated shell fragments in subglacial till on the mid-shelf constrains ice advance to after 26.4 ka BP. Initial retreat was underway before 24.4 ka BP, significantly earlier than previous reconstructions. Grounding-line retreat was accompanied by stillstands and/or localised readvances of the grounding-line. A large composite Mid-Shelf Grounding Zone Complex marks a major grounding-line position, with the ice grounded and the margin oscillating at this position by, and probably after, 23 ka BP. The continental shelf was ice-free by 17.1 cal. ka BP, but the ice sheet may have retained a marine margin until c. 15.3 ka BP. Retreat occurred in a glacimarine setting and the ice sheet was fringed by a floating ice-shelf. Collectively, this evidence indicates a dynamic and oscillatory marine-terminating ice sheet offshore of western Ireland during the last deglaciation.

KW - British-Irish Ice Sheet

KW - Continental shelf

KW - Glacimarine

KW - Grounding zone wedges

KW - Ice shelf

KW - Ice-sheet retreat

KW - Last Glacial Maximum

UR - https://www.scopus.com/pages/publications/85076174477

U2 - 10.1016/j.margeo.2019.106087

DO - 10.1016/j.margeo.2019.106087

M3 - Article

SN - 0025-3227

VL - 420

JO - Marine Geology

JF - Marine Geology

M1 - 106087

ER -

Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland

Abstract

Bibliographical note

Funding

UN SDGs

Keywords

Access to Document

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