Final deglaciation of the Malin Sea through meltwater release and calving events

Serena Tarlati, S. Benetti, Louise Callard, Colm Ó Cofaigh, P Dunlop, Aggeliki Georgiopoulou, Robin Edwards, Katrien J J Van Landeghem, Margot Saher, Richard Chiverrell, Derek Fabel, Steven Moreton, Sally Morgan, Chris D Clark

Research output: Contribution to journalArticle

Abstract

During the last glacial maximum, the British-Irish Ice Sheet (BIIS) extended to the shelf edge in the Malin Sea between Ireland and Scotland, delivering sediments to the Donegal Barra Fan (DBF). The analysis of well-preserved, glacially-derived sediment in the DBF provides new insights on the character of the BIIS final deglaciation and on paleoenvironmental conditions at the Younger Dryas (YD). Chaotic/laminated muds, ice-rafted debris (IRD)-rich layers and laminated sand-mud couplets are interpreted as mass transport deposits, plumites and turbidites from BIIS-transported sediments. Peaks in IRD concentration constrained by radiocarbon dating to after 18 ka cal. BP indicate discrete intervals of iceberg calving during the last stages of deglaciation. Glacially-derived sedimentation on the slope occurred until ~16.9 ka cal. BP. This is interpreted as the last time ice extended onto the shelf allowing glacial meltwater to reach the fan. Bioturbated and foraminifera-rich muds above glaciomarine sediments are interpreted as interglacial hemipelagites and contourites, with the presence of Zoophycos suggesting restoration of bottom currents at the transition between stadial and interstadial conditions. During the YD, Neogloboquadrina pachyderma sinistral abundances and an isolated peak in IRD indicate the temporary restoration of cold conditions and the presence of floating icebergs in the region.
Original languageEnglish
JournalScottish Journal of Geology
DOIs
Publication statusPublished - 6 Apr 2020

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Keywords

  • deglaciation
  • marine terminating ice sheet
  • ice rafted debris
  • Meltwater
  • Plumites
  • Younger Dryas

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