Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-10T12:12:10.472Z Has data issue: false hasContentIssue false
  • English
  • Français

Sedimentological signatures of the sub-Amery Ice Shelf circulation

Published online by Cambridge University Press:  01 October 2007

M.A. Hemer ,
A.L. Post ,
P.E. O'Brien ,
M. Craven ,
E.M. Truswell ,
D. Roberts  and
P.T. Harris
M.A. Hemer*
Affiliation:
Marine and Coastal Environment Group, Geoscience Australia, GPO Box 378, Canberra, ACT 2601, Australia
A.L. Post
Affiliation:
Marine and Coastal Environment Group, Geoscience Australia, GPO Box 378, Canberra, ACT 2601, Australia
P.E. O'Brien
Affiliation:
Marine and Coastal Environment Group, Geoscience Australia, GPO Box 378, Canberra, ACT 2601, Australia
M. Craven
Affiliation:
Australian Antarctic Division and Antarctic Climate andEcosystems Co-operative Research Centre, Private Bag 80, Hobart, TAS 7001, Australia
E.M. Truswell
Affiliation:
Department of Earth and Marine Science, Building 47, Australian National University, Canberra, ACT 2600, Australia
D. Roberts
Affiliation:
Institute of Antarctic and Southern Ocean Studies, University of Tasmania, Private Bag 77, Hobart, TAS 7001, Australia
P.T. Harris
Affiliation:
Marine and Coastal Environment Group, Geoscience Australia, GPO Box 378, Canberra, ACT 2601, Australia
*
*Corresponding author: now atCSIRO Marine and Atmospheric Research, GPO Box 1538, Hobart, TAS 7001, Australiamark.hemer@csiro.au
Get access Rights & Permissions [Opens in a new window]

Abstract

Two sediment cores collected from beneath the Amery Ice Shelf, East Antarctica describe the physical sedimentation patterns beneath an existing major embayed ice shelf. Core AM01b was collected from a site of basal freezing, contrasting with core AM02, collected from a site of basal melting. Both cores comprise Holocene siliceous muddy ooze (SMO), however, AM01b also recovered interbedded siliciclastic mud, sand and gravel with inclined bedding in its lower 27 cm. This interval indicates an episode of variable but strong current activity before SMO sedimentation became dominant. 14C ages corrected for old surface ages are consistent with previous dating of marine sediments in Prydz Bay. However, the basal age of AM01b of 28250 ± 230 14C yr bp probably results from greater contamination by recycled organic matter. Lithology, 14C surface ages, absolute diatom abundance, and the diatom assemblage are used as indicators of sediment transport pathways beneath the ice shelf. The transport pathways suggested from these indicators do not correspond to previous models of the basal melt/freeze pattern. This indicates that the overturning baroclinic circulation beneath the Amery Ice Shelf (near-bed inflow–surface outflow) is a more important influence on basal melt/freeze and sediment distributions than the barotropic circulation that produces inflow in the east and outflow in the west of the ice front. Localized topographic (ice draft and bed elevation) variations are likely to play a dominant role in the resulting sub-ice shelf melt and sediment distribution.

Keywords

Antarcticabaroclinic circulationsedimentsub-ice shelf circulation
Type
EARTH SCIENCES
Information
Antarctic Science , Volume 19 , Issue 4 , December 2007 , pp. 497 - 506
Copyright
Copyright © Antarctic Science Ltd 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Armand, L.K. 1997. The use of diatom transfer functions in estimating sea surface temperature and sea-ice in cores from the southeast Indian Ocean. PhD thesis, Australian National University, 287 pp. [Unpublished].Google Scholar
Craven, M., Allison, I., Brand, R., Elchiekh, A., Hunter, J., Hemer, M. & Donoghue, S. 2004. Initial borehole results from the Amery Ice Shelf hot-water drilling project. Annals of Glaciology, 39, 531–539.CrossRefGoogle Scholar
Dayton, P.K. & Oliver, J.S. 1977. Antarctic soft-bottom benthos in oligotrophic and eutrophic environments. Science, 197, 55–58.CrossRefGoogle ScholarPubMed
Dieckmann, G.S., Spindler, M., Lange, M.A., Ackley, S.F. & Eicken, H. 1991. Antarctic sea ice: a habitat for the foraminifer Neoglobquadrina pachyderma. Journal of Foraminiferal Research, 21, 182–189.CrossRefGoogle Scholar
Domack, E.W., Jull, A.J.T. & Nakao, S. 1991. Advance of East Antarctic outlet glaciers during the Hypsithermal: implications for the volume state of the Antarctic ice sheet under global warming. Geology, 19, 1059–1062.2.3.CO;2>CrossRefGoogle Scholar
Domack, E.W., O'Brien, P.E., Harris, P.T., Taylor, F., Quilty, P., DeSantis, L. & Raker, B. 1998. Late Quaternary sediment facies in Prydz Bay, East Antarctica and their relationship to glacial advance onto the continental shelf. Antarctic Science, 10, 236–246.CrossRefGoogle Scholar
Domack, E.W., Duran, D., Leventer, A., Ishman, S., Doane, S., McCallum, S., Amblas, D., Ring, J., Gilbert, R. & Prentice, M. 2005. Stability of the Larsen B Ice Shelf on the Antarctic Peninsula during the Holocene Epoch. Nature, 436, 681–685.CrossRefGoogle Scholar
Franklin, D. 1997. The sedimentology of Holocene Prydz Bay: sedimentary patterns and processes. PhD thesis, University of Tasmania, 258 pp. [Unpublished].Google Scholar
Fricker, H.A., Popov, S., Allison, I. & Young, N. 2001. Distribution of marine ice beneath the Amery Ice Shelf. Geophysical Research Letters, 28, 2241–2244.CrossRefGoogle Scholar
Gilbert, R. & Domack, E.W. 2003. The sedimentary record of disintegrating ice shelves in a warming climate, Antarctic Peninsula. Geochemistry Geophysics, Geosystems, 4, doi: 1029/2002GC000441.CrossRefGoogle Scholar
Grosfeld, K., Gerdes, R. & Determann, J. 1997. Thermohaline circulation and interaction between ice shelf cavities and adjacent open ocean. Journal of Geophysical Research, 102, 15595–15610.CrossRefGoogle Scholar
Harris, P.T. 2000. Sedimentological signatures of sub-ice shelf circulation: an example from Vincennes Bay, East Antarctica. Proceedings of the Royal Society Tasmania, 133(3), 57–62.CrossRefGoogle Scholar
Hellmer, H.H. & Jacobs, S.S. 1992. Ocean interactions with the base of the Amery Ice Shelf. Journal of Geophysical Research, 97, 20305–20317.CrossRefGoogle Scholar
Hemer, M.A. & Harris, P.T. 2003. Sediment core from beneath the Amery Ice Shelf, East Antarctica, suggest mid-Holocene ice shelf retreat. Geology, 31, 127–130.2.0.CO;2>CrossRefGoogle Scholar
Hemer, M.A., Hunter, J.R. & Coleman, R. 2006. Barotropic tides beneath the Amery Ice Shelf. Journal of Geophysical Research, doi: 10.1029/2006JC003622.CrossRefGoogle Scholar
Hughen, K.A., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J.W., Bertrand, C., Blackwell, P.G., Buck, C.E., Burr, G., Cutler, K.B., Damon, P.E., Edwards, R.L., Fairbanks, R.G., Friedrich, M., Guilderson, T.P., Kromer, B., McCormac, F.G., Manning, S., Ramsey, C.B., Reimer, P.J., Reimer, R.W., Remmele, S., Southon, J.R., Stuiver, M., Talamo, S., Taylor, F.W., van der Plicht, J. & Weyhenmeyer, C.E. 2004. Marine04 marine radiocarbon age calibration, 0–26 cal kyr bp. Radiocarbon, 46, 1059–1086.CrossRefGoogle Scholar
Ingolfsson, O., Hjort, C., Berkman, P., Bjorck, S., Colhoun, E.A., Goodwin, I.D., Hall, B.L., Hirakawa, K., Melles, M., Moller, P. & Prentice, M.L. 1998. Antarctic glacial history since the Last Glacial Maximum: an overview of the record on land. Antarctic Science, 10, 326–344.CrossRefGoogle Scholar
Kellogg, T.B. & Kellogg, D.E. 1988. Antarctic cryogenic sediments: biotic and inorganic facies of ice shelf and marine-based ice sheet environments. Palaeogeography, Palaeoclimatology, Palaeoecology, 67, 51–74.CrossRefGoogle Scholar
Macphail, M.K. & Truswell, E.M. 2004. Palynology of sites 1165, 1167. Proceedings of the Ocean Drilling Program, Scientific Results, 188, 1–20.Google Scholar
Miller, M.C., McCave, I.N. & Komar, P.D. 1977. Threshold of sediment motion under unidirectional currents. Sedimentology, 24, 507–527.CrossRefGoogle Scholar
O'Brien, P.E. & Leitchenkov, G. 1997. Deglaciation of Prydz Bay, East Antarctica, based on echo sounder and topographic features. Antarctic Research Series, 71, 109–125.Google Scholar
Post, A.L., Hemer, M.A., O'Brien, P.E., Roberts, D. & Craven, M. 2007. A history of benthic colonisation beneath the Amery Ice Shelf, East Antarctica. Marine Ecology Progress Series, 344, 29–37.CrossRefGoogle Scholar
Pudsey, C.J. & Evans, J. 2001. First survey of Antarctic sub-ice shelf sediments reveals mid-Holocene ice shelf retreat. Geology, 29, 787–790.2.0.CO;2>CrossRefGoogle Scholar
Ronan, T.E. Jr, Lipps, J.H. & DeLaca, T.E. 1978. Sediments and life under the Ross Ice Shelf (J-9), Antarctica. Antarctic Journal of the United States, 13, 141–142.Google Scholar
Stuiver, M. & Reimer, P.J. 1993. Extended 14C database and revized CALIB radiocarbon calibration program. Radiocarbon, 35, 215–230.CrossRefGoogle Scholar
Takahashi, K. & Bé, A.W.H. 1984. Planktonic foraminifera: factors controlling sinking speed, Deep-Sea Research, 31, 1477–1500.CrossRefGoogle Scholar
Taylor, F. & McMinn, A. 2002. Late Quaternary diatom assemblages from Prydz Bay, Eastern Antarctica. Quaternary Research, 57, 151–161.CrossRefGoogle Scholar
Truswell, E.M. 1991. Data report: palynology of sediments from Leg 119 drill sites in Prydz Bay, East Antarctica. Proceedings of the Ocean Drilling Program, Scientific Results, 119, 941–945.Google Scholar
Webb, P.N., Ronan, T.E. Jr., Lipps, J.H. & DeLaca, T.W. 1979. Miocene glaciomarine sediments from beneath the southern Ross Ice Shelf, Antarctica. Science, 203, 435–437.CrossRefGoogle ScholarPubMed
Whitehead, J.M., Quilty, P.G., McKelvey, B.C. & O'Brien, P.E. 2006. A review of the Cenozoic stratigraphy and glacial history of the Lambert Graben–Prydz Bay region, East Antarctica. Antarctic Science, 18, 83–100.CrossRefGoogle Scholar
Williams, M.E., Warner, R.C. & Budd, W.F. 1998. The effects of ocean warming on melting and ocean circulation under the Amery Ice Shelf, East Antarctica. Annals of Glaciology, 27, 75–80.CrossRefGoogle Scholar
Williams, M.J.M., Grosfeld, K., Warner, R.C., Gerdes, R. & Determann, J. 2001. Ocean circulation of ice-ocean interaction beneath the Amery Ice Shelf, Antarctica. Journal of Geophysical Research, 106, 22383–22400.CrossRefGoogle Scholar