Maximum extent and dynamic behaviour of the last British Irish Ice Sheet west of Ireland

Jared Lee Peters, Sara Benetti, Paul Dunlop, Colm O' Cofaigh

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

A complete reconstruction of the last BritisheIrish Ice Sheet (BIIS) is hindered by uncertainty surrounding its offshore extent and dynamic behaviour. This study addresses this problem by reconstructing the depositional history of four sediment cores taken from a series of sinuous glacigenic sediment ridges on the continental shelf west of Ireland. We present new geomorphic, sedimentary and micro paleontological data that record a maximum westward BIIS extent that was at least 80 km farther offshore from any previous estimates. The data suggests that a large ice shelf formed over parts of the shelf prior to retreat. This new data increases the areal extent of grounded BIIS ice by ~6700 km2 from previous estimates, which represents a ~3% increase in the Irish Sector of the ice sheet. Three new AMS radiocarbon dates demonstrate for the first time that the BIIS advanced to the shelf edge during last glaciation (Late Midlandian/Late Devensian), with ice advance onto the Porcupine Bank occurring after 24,720 ± 260 yr Cal. BP. Deglaciation was complete by 19,182 ± 155 yr Cal. BP, thus constraining BIIS occupation over the Porcupine Bank to less than 5500 years. Estimated retreat rates of marine terminating ice across the shelf range from ~70 to 180 myr�-1.
LanguageEnglish
Pages48-68
JournalQuaternary Science Reviews
Volume128
DOIs
Publication statusPublished - Nov 2015

Fingerprint

Ireland
ice sheet
ice
bank
last ice sheet
occupation
reconstruction
Devensian
uncertainty
last glaciation
ice shelf
accelerator mass spectrometry
shelf break
deglaciation
sediment core
history
continental shelf
Sediment
Retreat
sediments

Keywords

  • British-Irish Ice Sheet
  • Marine-terminating ice margin
  • Glaciation
  • Maximum extent
  • Porcupine Bank
  • Continental shelf
  • Ice shelf
  • Radiocarbon
  • Sedimentology
  • Benthic foraminifera
  • Geomorphology

Cite this

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title = "Maximum extent and dynamic behaviour of the last British Irish Ice Sheet west of Ireland",
abstract = "A complete reconstruction of the last BritisheIrish Ice Sheet (BIIS) is hindered by uncertainty surrounding its offshore extent and dynamic behaviour. This study addresses this problem by reconstructing the depositional history of four sediment cores taken from a series of sinuous glacigenic sediment ridges on the continental shelf west of Ireland. We present new geomorphic, sedimentary and micro paleontological data that record a maximum westward BIIS extent that was at least 80 km farther offshore from any previous estimates. The data suggests that a large ice shelf formed over parts of the shelf prior to retreat. This new data increases the areal extent of grounded BIIS ice by ~6700 km2 from previous estimates, which represents a ~3{\%} increase in the Irish Sector of the ice sheet. Three new AMS radiocarbon dates demonstrate for the first time that the BIIS advanced to the shelf edge during last glaciation (Late Midlandian/Late Devensian), with ice advance onto the Porcupine Bank occurring after 24,720 ± 260 yr Cal. BP. Deglaciation was complete by 19,182 ± 155 yr Cal. BP, thus constraining BIIS occupation over the Porcupine Bank to less than 5500 years. Estimated retreat rates of marine terminating ice across the shelf range from ~70 to 180 myr�-1.",
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Maximum extent and dynamic behaviour of the last British Irish Ice Sheet west of Ireland. / Peters, Jared Lee; Benetti, Sara; Dunlop, Paul; O' Cofaigh, Colm.

Vol. 128, 11.2015, p. 48-68.

Research output: Contribution to journalArticle

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