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

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

Research output: Contribution to journalArticle

5 Citations (Scopus)

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.
Original languageEnglish
Pages (from-to)251-272
JournalMarine Geology
Volume369
DOIs
Publication statusPublished - 31 Aug 2015

Keywords

  • Relative sea-level change
  • post-glacial transgression
  • multibeam echosounder
  • seismo-stratigraphy
  • litho-stratigraphy
  • Bantry Bay

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