Late Quaternary evolution and sea-level history of a glaciated marine embayment, Bantry Bay, SW Ireland

Plets, R.M.K.; Callard, S.L.; Cooper, J.A.G.; Long, A.J.; Quinn, R.J.; Belknap, D.F.; Edwards, R.J.; Jackson, D.W.T.; Kelley, J.T.; Long, D.; Milne, G.A.; Monteys, X.

Abstract

Ireland experienced a spatially complex pattern of relative sea-level (RSL) changes and shoreline development caused by the interplay of isostatic and eustatic (ice equivalent sea level) processes since the Last Glacial Maximum (LGM). Using a combination of high-resolution marine geophysical data, vibrocores, foraminiferal analysis and 10 AMS radiocarbon dates, we reconstruct the Late Quaternary evolution and RSL history of Bantry Bay, a large (40 km long, 5–10 km wide) embayment in SW Ireland. The data indicate two infill phases: one before and one after the LGM, separated by glacial and lowstand sediments. The pre-LGM history is not dated and the depositional history is inferred. A large sediment lobe formed at the outer edge of Bantry Bay as a lowstand ice-proximal glacimarine outwash system as the ice retreated after the LGM, at a sea level ca. 80 m lower than present. Iceberg scour immediately west of this location likely relate to the break-up of the local Kerry–Cork Ice Cap. Long curvilinear ridges, seen both offshore and on top of the sediment lobe, probably formed as shoreface ridges under stronger-than-present tidal currents during a period of RSL stability (pre-14.6 ka cal BP). A subsequent infill phase is characterised by a basin-wide erosional (ravinement) surface and the deposition of inter- and sub-tidal estuarine sediments. Although our data support the general trends, our stratigraphic and radiocarbon data suggest a higher sea level between 11 and 13.5 ka cal BP than predicted by existing glacial isostatic adjustment models.

Citation

Plets, R., Callard, S., Cooper, J., Long, A., Quinn, R., Belknap, D., …Monteys, X. (2015). Late Quaternary evolution and sea-level history of a glaciated marine embayment, Bantry Bay, SW Ireland. Marine Geology, 369, 251-272. https://doi.org/10.1016/j.margeo.2015.08.021

• Journal Article Type: Article
• Acceptance Date: Aug 31, 2015
• Publication Date: Nov 1, 2015
• Deposit Date: Oct 13, 2015
• Publicly Available Date: Mar 5, 2017
• Journal: Marine Geology
• Print ISSN: 0025-3227
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 369
• Pages: 251-272
• DOI: https://doi.org/10.1016/j.margeo.2015.08.021
• Keywords: Relative sea-level change, Post-glacial transgression, Multibeam echosounder, Seismo-stratigraphy, Litho-stratigraphy, Bantry Bay.
• Public URL: https://durham-repository.worktribe.com/output/1420737