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

• Published in: Marine Geology
• Main Authors: 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.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2015
• Subjects: Relative sea-level change; Post-glacial transgression; Multibeam echosounder; Seismo-stratigraphy; Litho-stratigraphy; Bantry Bay; Ice cap
• Online Access: http://dro.dur.ac.uk/16611/; http://dro.dur.ac.uk/16611/1/16611.pdf; https://doi.org/10.1016/j.margeo.2015.08.021

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.