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Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland
- Source :
- Marine geology, 2020, Vol.420, pp.106087 [Peer Reviewed Journal], Marine Geology
- Publication Year :
- 2020
- Publisher :
- Elsevier, 2020.
-
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.
- Subjects :
- geography
geography.geographical_feature_category
010504 meteorology & atmospheric sciences
Continental shelf
Geology
Last Glacial Maximum
010502 geochemistry & geophysics
Oceanography
01 natural sciences
Ice shelf
law.invention
Geochemistry and Petrology
law
Deglaciation
Submarine pipeline
Radiocarbon dating
Ice sheet
Bay
0105 earth and related environmental sciences
Subjects
Details
- Language :
- English
- ISSN :
- 00253227
- Database :
- OpenAIRE
- Journal :
- Marine geology, 2020, Vol.420, pp.106087 [Peer Reviewed Journal], Marine Geology
- Accession number :
- edsair.doi.dedup.....180468203631b890393b1d5ff0080eb9