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Landform modification by palaeo-ice streams in east-central Ireland

  • Jasper Knight (a1), G. McCarron Stephen (a1) and A. Marshall McCabe (a1)

Abstract

In eastern Ireland, subglacial bedforms including drumlins and Rogen moraines were modified by headward erosion along two ice streams which had overlapping flow tracks. The ice streams, which had tidewater termini, are dated by geochronometric and morphostratigraphic methods to <15.014 C kyr BP (Castleblaney ice stream) and ~13.814C kyr BP (Armagh ice stream). Bedforms along ice-stream tracks show a morphological continuum which reflects a down-ice increase in the degree of modification by ice-stream activity (i.e. resulting in unmodified →remoulded/overprinted →crosscut →streamlined bedforms). The down-ice changes in bedform types are inferred to relate to changes in subglacial drainage and sediment-transport mechanisms. Bedform and sedimentary evidence suggest that discrete subglacial meltwater channels which developed up- ice changed in a down-ice direction to unchannelized flows which deepened towards the ice margin. Meltwater release from subglacial cavities, and produced by strain heating at sheared ice-stream margins, probably helped support ice-stream flow, which ended as the volume of subglacial meltwater discharge decreased. Dated millennial-scale cycles of ice activity may be related to instability at tidewater margins, followed by complex thermal and hydraulic responses within the ice mass.

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References

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Alley, R. B., Anandakrishnan, S., Bentley, C. R. and Lord, N.. 1994. A water-piracy hypothesis for the stagnation of Ice Stream C, Antarctica. Ann. Glacial., 20, 187-194.
Blankenship, D. D., Bentley, C. R., Rooney, S.T. and Alley, R. B.. 1986. Seismic measurements reveal a saturated porous layer beneath an active Antarctic ice stream. Nature, 322(6074), 54-57.
Boulton, G.S. 1987. A theory of drumlin formation by subglacial sediment deformation. In Menzies, J. and Rose, J., eds. Drumlin Symposium. Rotterdam, A. Balkema, A., 25-80.
Dardis, G. F. and McCabe, A. M.. 1983. Facies of subglacial channel sedimentation in late-Pleistocene drumlins, northern Ireland. Boreas, 12 (4), 263-278.
Dardis, G. F., McCabe, A. M. and Mitchell, W. I.. 1984. Characteristics and origins of lee-side stratification sequences in Late Pleistocene drumlins, northern Ireland. Earth Surf Processes Landforms, 9(5), 409-424.
Echelmeyer, K. A., Harrison, W. D., Larsen, C. and Mitchell, J. E.. 1994. The role of the margins in the dynamics of an active ice stream. J Gladol., 40(136), 527-538.
Hattestrand, C. 1997. Ribbed moraines and Fennoscandian palaeoglaciology. Stockholm, Stockholm University. Department of Physical Geography. (Av- handling/Dissertation 9.)
Hicock, S. R. and Fuller, E. A.. 1995. Lobal interactions, rheologic superimposition, and implications for a Pleistocene ice stream on the continental shelf of British Columbia. Geomorphology., 14 (2), 167-184.
Hughes, T. 1986. The Jakobshavns effect. Geophys. Res. Lett., 13 (1), 46-48.
Kamb, B. 1987. Glacier surge mechanism based on linked cavity configuration of the basal water conduit system. J. Geophys. Res., 92 (B9), 9083-9100.
Kaufman, D. S., Miller, G. H., Stravers, J. A. and Andrews, J.T.. 1993. Abrupt early Holocene (9.9-9.6 ka) ice-stream advance at the mouth of Hudson Strait, Arctic Canada. Geology, 21(12), 1063-1066.
Knight, J. and McCabe, A. M.. 1997. Identification and significance of ice-flow-transverse subglacial ridges (Rogen moraines) in northern central Ireland. J. Quat. Sci., 12(6), 519-524.
Knight, J., McCarronandA, S. G.. McCabe, M.. 1997. Geologic evidence for controls on Late Pleistocene ice activity cycles in Ireland. [Abstract.] EOS, 78(46), Fall Meeting Supplement, F248.
Lundqvist, J. 1989. Rogen (ribbed) moraine-identification and possible origin. Sediment. Geol., 62(3-4), 281-292.
McCabe, A. M. 1996. Dating and rhythmicity from the last deglacial cycle in the British Isles. J. Geol. Soc., London, 153(4), 499-502.
McCabe, A. M. 1997. Geological constraints on geophysical models of relative sea-level change during deglaciation of the western Irish Sea basin. J. Geol. Soc., London, 154(4), 601-604.
McCabe, A. M. and Clark, P. U.. 1998. Ice-sheet variability around the North Atlantic Ocean during the last glaciation. Mature, 392(6674), 373-377.
McCabe, A. M. and Haynes, J. R.. 1996. A late Pleistocene intertidal boulder pavement from an isostatically emergent coast, Dundalk Bay, eastern Ireland. Earth Surf. Processes Landforms, 21(6), 555-572.
McCabe, A. M. and Cofaigh, C. O. 1994. Sedimentation in a subglacial lake, Enniskerry, eastern Ireland. Sediment. Geol., 91(1-4), 57-95.
McCabe, A. M., Dardis, G. F. and Hanvey, P. M.. 1984. Sedimentology of a late Pleistocene submarine-moraine complex, County Down, Northern Ireland. J. Sediment. Petrol., 54(3), 716-730.
McCabe, A. M., Haynes, J. R. and MacMillan, N. F.. 1986. Late-Pleistocene tidewater glaciers and glaciomarine sequences from north County Mayo, Republic of Ireland. J. Quat. Sci., 1(1), 73-84.
McCabe, A. M., Dardis, G. F. and Hanvey, P. M.. 1987. Sedimentation at the margins of a late Pleistocene ice-lobe terminating in shallow marine environments, Dundalk Bay, eastern Ireland. Sedimentology, 34(3), 473-493.
McCabe, A. M., Knight, J. and McCarron, S. G.. 1999. Ice flow stages and glacial bedforms in north central Ireland: a record of rapid environmental change during the last glacial termination. J. Geol. Soc., London, 156(1), 63-72.
Oppenheimer, M. 1998. Global warming and the stability of the West Antarctic ice sheet. Mature, 393(6683), 325-332.
Shaw, J. 1996. A meltwater model for Laurentide subglacial landscapes. In McCann, S. B. and Ford, D. C., eds. Geomorphologysansfrontieres. Chichester, etc., JohnWiley and Sons, 181-236.
Sjogren, D. B. and Rains, R. B.. 1995. Glaciofluvial erosional morphology and sediments of the Coronation-Spondin Scabland, east-central Alberta. Can. J. Earth Sci., 32(5), 565-578.
Synge, F. M. 1969. The Würm ice limit in the west of Ireland. In Wright, H. E., Jr, ed. Quaternary geology and climate. Washington, DC, National Academy of Sciences, 89-92.

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