The last British Ice Sheet: growth, maximum extent and deglaciation

Article English OPEN
Lindsay J. Wilson1, William E. N. Austin1 (2002)

The growth, maximum lateral extent and deglaciation of the last British Ice Sheet (BIS) has been reconstructed using sediment, faunal and stable isotope methods from a sedimentary record recovered from the Barra Fan, north-west Scotland. During a phase of ice sheet expansion postdating the early “warmth” of Marine Isotope Stage 3 (MIS 3), ice rafting events, operating with a cyclicity of approximately 1500 years, are interspersed between warm, carbonate-rich interstadials operating with a strong Dansgaard-Oeschger (D-O) cyclicity. The data suggest that the BIS expanded westwards to the outer continental shelf break shortly after 30 Ky BP (before present) and remained there until about 15 Ky BP. Within MIS 2, as the ice sheet grew to its maximum extent, the pronounced periodicities which characterize MIS 3 are lost from the record. The exact timing of the Last Glacial Maximum is difficult to define in this record; but maxima in Neogloboquadrina pachyderma (sinistral) Ø18O are observed between 21-17 Ky BP. A massive discharge of ice-rafted detritus, coincident with Heinrich event 1, is observed at about 16 Ky BP. Deglaciation of the margin is complete by about 15 Ky BP and surface waters warm rapidly after this date.
  • References (36)
    36 references, page 1 of 4

    Andrews, J. T., Austin, W. E. N., Bergsten, H. & Jennings, A. E. 1996: The Late Quaternary palaeoceanography of North Atlantic margins: an introduction. In J. T. Andrews et al. (eds): Late Quaternary palaeoceanography of the North Atlantic margins. Spec. Publ. 111. Pp. 1–6. Geological Society of London.

    Austin, W. E. N. 1991: Late Quaternary benthonic foraminiferal stratigraphy of the western UK continental shelf. PhD thesis, University of Wales.

    Austin, W. E. N., Bard, E., Hunt, J. B., Kroon, D. & Peacock, J. D. 1995: The 14C age of the Icelandic Vedde Ash: implications for Younger Dryas marine reservoir age corrections. Radiocarbon 37, 53–62.

    Austin, W. E. N. & Evans, J. R. 2000: North East Atlantic benthic foraminifera: modern distribution patterns and palaeoecological signiÞcance. J. Geol. Soc. 157, 679–691.

    Austin, W. E. N. & Kroon, D. 1996: Late glacial sedimentology, foraminifera and stable isotope stratigraphy of the Hebridean continental shelf, northwest Scotland. In J. T. Andrews et al. (eds): Late Quaternary palaeoceanography of the North Atlantic margins. Spec. Publ. 111. Pp. 187–213. Geological Society of London.

    Austin, W. E. N. & Kroon, D. 2001: Deep sea ventilation of the northeastern Atlantic during the last 15,000 years. Glob. Planet. Change 30, 13–31.

    Bard, E., Arnold, M., Hamelin, B., Tisnerat-Laborde, N. & Cabioch, G. 1998: Radiocarbon calibration by means of mass spectrometric Th230/U234 and C14 ages of corals: an updated database including samples from Barbados, Mururoa and Tahiti. Radiocarbon 40, 1085–1092.

    Benn, D. I. 1997: Glacier ßuctuations in western Scotland. Quat. Int. 38/39, 137–149.

    Bond, G. C., Broecker, W., Johnsen, S., McManus, J., Labeyrie, L., Jouzel, J. & Bonani, G. 1993: Correlations between climate records from North Atlantic sediments and Greenland ice. Nature 365, 143–147.

    Bond, G. C. & Lotti, R. 1995: Iceberg discharges into the North Atlantic on millennial time scales During the last glaciation. Science 267, 1005–1010.

  • Metrics
    No metrics available
Share - Bookmark