Diatom assemblages in two Holocene sediment cores (GC1 and GC2) from the Mac. Robertson Shelf, East Antarctica, are compared with modern sedimentary diatom assemblages from the same area. Open marine deposition commenced in Iceberg Alley (GC1), on the outer continental shelf, .10.7 adj. 14C kyr BP. Chaetoceros resting spores, which may indicate water-column stabilization from melting glacial and/or sea ice or the maximum summer sea-ice retreat, dominate the diatom assemblage. Approximately 7.5 adj. 14C kyr BP, a sea-ice diatom assemblage was deposited. This assemblage is similar to that being deposited in the surface sediments of the Mac. Robertson Shelf today and suggests that perennial sea ice has persisted in the vicinity of Iceberg Alley since that time. Interbedded within the sea-ice assemblage, however, areCorethron-rich sedi ment layers that suggest mid-to late-Holocene high-productivity events associated with a climatic optimum. The diatom record from Nielsen Basin (GC2), on the inner continental shelf, is relatively uniform compared to that in GC1. Glacial ice was present over the regionc. .5.6 adj. 14C kyr BP and a dissolution diatom assemblage was deposited beneath it. Following ice retreat, an ice-edge diatom assemblage was deposited briefly before sea-ice conditions similar to that on the continental shelf today developed. There is no evidence in GC2 for the mid-to late-Holocene high-productivity events identified in GC1.
Adamson, D.A. and Pickard, J.1986: Cainozoic history of the Vestfold Hills. In Pickard, J. , editor,Antarctic oasis. Terrestrial environments and history of the Vestfold Hills, Sydney: Academic Press , 63–93.
2.
Cunningham, W.L. , Leventer, A. , Andrews, J.T. , Jennings, A.E. and Licht, K.J.1999: Late Pleistocene-Holocene marine conditions in the Ross Sea, Antarctica: evidence from the diatom record .The Holocene9, 129–139 .
3.
DeFelice, D. and Wise, S.1981: Surface lithofacies, biofacies, and diatom diversity patterns as models for delineation of climatic change in southeast Atlantic Ocean .Marine Micropaleontology6, 29–70 .
4.
Domack, E. , Jull, A. , Anderson, J. , Linick, T. and Williams, C.1989: Application of tandem accelerator mass-spectrometer dating to Late Pleistocene-Holocene sediments of the East Antarctic continental shelf .Quaternary Research31, 277–287 .
5.
Domack, E. , Jull, A. and Donahue, D.1991a: Holocene chronology for the unconsolidated sediments at Hole 740A: Prydz Bay, East Antarctica . Proceedings of the Ocean Drilling Program, Scientific Results119, 727–750 .
6.
Domack, E. , Jull, A. and Nakao, S.1991b: Advance of East Antarctic outlet glaciers during the hypsithermal: implications for the volume of the Antarctic ice sheet under global warming .Geology19, 1059–1062 .
7.
Domack, E. , Leventer, A. , Dunbar, R. , Taylor, F. , Brachfeld, S. , Sjunneskog, C. and ODP Leg 178 Scientific Party2001: Chronology of the Palmer Deep site, Antarctic Peninsula: a Holocene palaeoenvironmental reference for the circum-Antarctic .The Holocene11, 1–9 .
8.
Domack, E. , O'Brien, P. , Harris, P. , Taylor, F. , Quilty, P.G. , De Santis, L. and Raker, B.1998: Late Quaternary sediment facies in Prydz Bay, East Antarctica and their relationship to glacial advance on the continental shelf .Antarctic Science10, 236–246 .
9.
Gersonde, R. and Wefer, G.1987: Sedimentation of biogenic siliceous particles in Antarctic waters from the Atlantic Sector .Marine Micropaleontology11, 311–332 .
10.
Harris, P. and O'Brien, P.1996: Geomorphology and sedimentology of the continental shelf adjacent to Mac. Robertson Land, East Antarctica: a scalped shelf .Geo-Marine Letters16, 287–296 .
11.
Harris, P. and O'Brien, P.1998: Bottom currents, sedimentation and ice-sheet retreat facies successions on the Mac. Robertson Shelf, East Antarctica .Marine Geology151, 47–72 .
12.
Harris, P. , O'Brien, P. , Sedwick, P. and Truswell, E.1996: Late Quaternary history of sedimentation on the Mac. Robertson Shelf, East Antarctica: problems with 14C-dating of marine sediment cores .Papers and Proceedings of the Royal Society of Tasmania130, 47–53 .
13.
Harris, P. , Taylor, F. , Leitchenkov, G. , Pushina, Z. , O'Brien, P. and Masotov, V.N.1998: Lithofacies distribution in relation to the geomorphic provinces of Prydz Bay, East Antarctica .Antarctic Science10, 227–235 .
14.
Hasle, G.1969: An analysis of phytoplankton of the Pacific Southern Ocean: abundance, composition, and distribution during the Brategg Expedition, 1947–1948 .Hvalradets Skrifter52, 1–168 .
15.
Jordan, R. , Priddle, J. , Pudsey, C. , Barker, P. and Whitehouse, M.1991: Unusual diatom layers in Upper Pleistocene sediments from the northern Weddell Sea .Deep-Sea Research38, 829–843 .
16.
Katoh, K.1993: Deletion of less-abundant species from ecological data . Diatom8, 1–5 .
17.
Kellogg, D. and Kellogg, T.1988: Antarctic cryogenic sediments: biota and inorganic facies of ice shelf and marine-based ice sheet environments . Palaeogeography, Palaeoclimatology, Palaeoecology67, 51–74 .
18.
Leventer, A.1992: Modern distribution of diatoms in sediments from the George V Coast, Antarctica .Marine Micropaleontology19, 315–332 .
19.
Leventer, A. and Dunbar, R.1988: Recent diatom record of McMurdo Sound, Antarctica: implications for history of sea ice extent .Paleoceanography3, 259–274 .
20.
Leventer, A. , Domack, E.W. , Ishman, S.E. , Brachfeld, S. , McClennen, C.E. and Manley, P.1996: Productivity cycles of 200–300 years in the Antarctic Peninsula region: understanding linkages among the sun, atmosphere, oceans, sea ice, and biota .GSA Bulletin108, 1626–1644 .
21.
Leventer, A. , Dunbar, R. and DeMaster, D.J.1993: Diatom evidence for Late Holocene climatic events in Granite Harbor, Antarctica .Paleoceanography8, 373–386 .
22.
Lizotte, M.P. and Sullivan, C.W.1991: Rates of photoadaptation in sea ice diatoms from McMurdo Sound, Antarctica .Journal of Phycology27, 367–373 .
23.
Lorius, C. , Jouzel, J. and Raynaud, D.1985: The ice core record: past archive of the climate and signpost of the future .Philosophical Transactions of the Royal Society of London38, 227–234 .
24.
Massom, R.A. , Harris, P.T. , Michael, K.J. and Potter, M.J.1998: The distribution and formative processes of latent-heat polynyas in East Antarctica .Annals of Glaciology27, 420–426 .
25.
McMinn, A.1995: Comparison of diatom preservation between oxic and anoxic basins .Diatom Research10, 145–151 .
26.
McMinn, A. , Gibson, J. , Hodgson, D. and Aschman, J.1995: Nutrient limitation in Ellis Fjord, eastern Antarctica .Polar Biology15, 269–276 .
27.
Nelson, D.M. and Smith, W.O.1986: Phytoplankton bloom dynamics of the western Ross Sea ice edge–II. Mesoscale cycling of nitrogen and silicon .Deep-Sea Research33, 1389–1412 .
28.
Nelson, D.M. and Smith, W.O.1991: Sverdrup revisited: critical depths, maximum chlorophyll levels, and the control of Southern Ocean productivity by the irradiancemixing regime .Limnology and Oceanography36, 1650–1661 .
29.
Nelson, D.M. , Smith, W.O. , Gordon, L.I. and Huber, B.A.1987: Spring distributions of density, nutrients and phytoplankton biomass in the ice edge zone of the Weddell-Scotia Sea .Journal of Geophysical Research92, 7181–7190 .
30.
O'Brien, P. , Truswell, E. and Burton, T.1994: Morphology, seismic stratigraphy and sedimentation history of the Mac. Robertson Shelf, East Antarctica .Terra Antartica1, 407–408 .
31.
Pudsey, C.1990: Grain size and diatom content of hemipelagic sediments at Site 697, ODP Leg 113; a record of Pliocene-Pleistocene climate .Proceedings of the Ocean Drilling Program, Scientific Results113, 111–120 .
32.
Pushina, Z. , Kolobov, D. and Druzhinina, N.1997: Biostratigraphy and paleoecology of the bottom sediments in Prydz Bay. In Ricci, C. , editor, The Antarctic region: geological evolution and processes, Siena: Terra Antartic Publications , 869–874.
33.
Rathburn, A. , Pichon, J. , Ayress, M. and DeDeckker, P.1997: Microfossil and stable isotope evidence for changes in Late Holocene palaeoproductivity and palaeoceanographic conditions in the Prydz Bay region of Antarctica .Palaeogeography, Palaeoclimatology, Palaeoecology131, 485–510 .
34.
Saari, M.R. , Yuen, D.A. and Schubert, G.1997: Climatic warming and basal melting of large ice sheets: possible implications for East Antarctica . Geophysical Research Letters14, 33–36 .
35.
Sedwick, P.N. , Harris, P.T. , Robertson, L.G. , McMurtry, G.M. , Cremer, M.D. and Robinson, P.1999: A geochemical study of marine sediments from the Mac. Robertson Shelf, East Antarctica: initial results and palaeoenvironmental implications .Annals of Glaciology27, 268–274 .
36.
Sedwick, P.N. , Harris, P.T. , Robertson, L.G. , McMurtry, G.M. , Cremer, M.D. and Robinson, P.2001: Holocene sediments from the continental shelf of Mac. Robertson Land, East Antarctica.Paleoceanography, in press.
37.
Shi, G.R.1993: Multivariate data analysis in palaeoecology and palaeobiogeography–a review .Palaeogeography, Palaeoclimatology, Palaeo-ecology105, 199–234 .
38.
Stagg, H.1985: The structure and origin of Prydz Bay and Mac. Robertson Shelf, East Antarctica .Tectonophysics114, 315–340 .
39.
Taylor, F. 1999: Sedimentary diatom assemblages of Prydz Bay and Mac. Robertson Shelf, East Antarctica, and their use as palaeoecological indicators. PhD thesis, University of Tasmania, 284 pp.
40.
Taylor, F. , McMinn, A. and Franklin, F.1997: Distribution of diatoms in surface sediments from Prydz Bay, Antarctica .Marine Micropaleontology32, 209–229 .
41.
Taylor, F. , Whitehead, J. and Domack, E.2001: Holocene paleoclimate change in the Antarctic Peninsula: evidence from the diatom, sedimentary and geochemical record .Marine Micropaleontology41(1–2), 25–44 .
42.
Truesdale, R. and Kellogg, T.1979: Ross Sea diatoms: modern assemblage distributions and their relationship to ecologic, oceanographic and sedimentary conditions .Marine Micropaleontology4, 13–31 .
