Skip to main content Accessibility help
×
Home

A geochemical study of marine sediments from the Mac. Robertson shelf, East Antarctica: initial results and palaeoenvironmental implications

  • P. N. Sedwick (a1), P.T. Harris (a1) (a2), L. G. Robertson (a1), G. M. Mcmurtry (a3), M. D. Cremer (a3) and P. Robinson (a4)...

Abstract

Sediments from the Antarctic continental margin may provide detailed palaeoenvironmental records for Antarctic shelf waters during the late Quaternary. Here we present results from a palaeoenvironmental study of two sediment cores recovered from the continental shelf off Mac. Robertson Land, East Antarctica. These gravity cores were collected approximately 90 km apart from locations on the inner and outer shelf. Both cores are apparently undisturbed sequences of diatom ooze mixed with fine, quartz-rich sand. Core stratigraphies have been established from radiocarbon analyses of bulk organic carbon. Down-core geochemical determinations include the lithogenic components AÍ and Fe, biogenic components opal and organic carbon, and palaco-redox proxies Mn, Mo and U. We use the geochemical data to infer past variations in the deposition of biogenic and lithogenic materials, and the radiocarbon dates to estimate average sediment accumulation rates. The Holocene record of the outer-shelf core suggests three episodes of enhanced diatom export production at about 1.8, 3.8 and 5.5 ka BP, as well as less pronounced bloom episodes which occurred over a shorter period. Average sediment accumulation rates at this location range from 13.7 cm ka−1 in the late Pleistocene early Holocene to 82 cm ka−1 in the late Holocene, and suggest that the inferred episodes of enhanced biogenic production lasted 100-1000 years. in contrast, data for the inner-shelf core suggest that there has been a roughly constant proportion of biogenic and lithogenic material accumulating during the middle to late Holocene, with a greater proportion of biogenic material relative to the outer shelf. Notably, there is an approximately 7-fold increase in average sediment accumulation rate (from 24.5 to 179 cm ka−1) at this inner-shelf location between the middle and late Holocene, with roughly comparable increases in the mass accumulation rates of both biogenic and lithogenic material. This may represent changes in sediment transport processes, or reflect real increases in pelagic sedimentation in this region during the Holocene. Our results suggest quite different sedimentation regimes in these two shelf locations during the middle to late Holocene.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      A geochemical study of marine sediments from the Mac. Robertson shelf, East Antarctica: initial results and palaeoenvironmental implications
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      A geochemical study of marine sediments from the Mac. Robertson shelf, East Antarctica: initial results and palaeoenvironmental implications
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      A geochemical study of marine sediments from the Mac. Robertson shelf, East Antarctica: initial results and palaeoenvironmental implications
      Available formats
      ×

Copyright

References

Hide All
Anderson, J. B. and Molnia, B. F.. 1989. Glacial-marine sedimentation. Washington, DC, American Geophysical Union. (Short Course in Geology 9).
Berner, R. A. 1980. Early diagenesis. Prineton, NJ, Princeton University Press.
Calvert, S. E., and Pedersen, T. F.. 1993. Geochemistry of recent oxic and anoxic marine sediments: implications for the geological record. Mar. Geol., 113(1-2), 6788.
Charles, C. D., Froelich, P. N., Zibello, M. A., Mortlock, R. A. and Morley, J. J.. 1991. Biogenic opal in Southern Ocean sediments over the last 450,000 years: implications for surface water chemistry and circulation. Paleoceanography, 6(6), 697–728.
Comiso, J. C., McClain, C. R., Sullivan, C. W., Ryan, J. P. and Leonard, C. L.. 1993. Coastal zone color scanner pigment concentrations in the Southern Ocean and relationships to geophysical surface features. J. Geophys. Res., 98(C2), 24192451.
Crusius, J., Calvert, S., Pedersen, T. and Sage, D.. 1996. Rhenium and molybdenum enrichments in sediments as indicators of oxic, suboxic and sulfidic conditions of deposition. Earth Planet. Sci. Lett., 145(1-4), 6578.
Deacon, G. 1984. The Antarctic circumpolar ocean. Cambridge, Cambridge University Press.
Deer, W. A., Howie, R. A. and Zussman, J.. 1977. An introduction to the rock-forming minerals. London, Longman.
Domack, E. W., Mashiotta, T. A., Burkley, L. A. and Ishman, S. E.. 1993. 300-year cyclicity in organic matter preservation in Antarctic fjord sediments. In Kennett, J. P. and Warnke, D. A., eds. The Antarctic paleoenvironment: a perspective on global change. Washington, DC, American Geophysical Union, 265272. (Antarctic Research Series 60.)
Dymond, J., Suess, E. and Lyle, M.. 1992. Barium in deep-sea sediment: a geochemical proxy for paleoproductivity. Paleoceanography. 1(2), 163181.
Frank, M. and 7 others. 1995. Sediment redistribution versus paleoproductivity change: Weddell Sea margin sediment stratigraphy and biogenic particle flux of the last 250,000 years deduced from 230Thex, 10Be and biogenic barium profiles. Earth Planet. Sci. Lett., 136(3-4), 559573.
Harris, P. T. and O'Brien, P. E.. 1996. Geomorphology and sedimentology of the continental shelf adjacent to Mac. Robertson Land, East Antarctica: a scalped shelf. Geo-Mar. Lett., 16(4), 287–296.
Harris, P. T., Howard, W., O'Brien, P. E., Sedwick, P. N. and Sikes, E. L.. in press. Quaternary Antarctic ice-sheet fluctuations and Southern Ocean palaeoceanography: natural variability studies at the Antarctic CRC. J. Australian Geol. Geophys.
Jordan, R. W., Priddle, J., Pudsey, C. J., Barker, P. F. and Whitehouse, M. J.. 1991. Unusual diatom layers in Upper Pleistocene sediments from the northern Weddell Sea. Deep-Sea Res., 38(7), 829–843.
Kumar, N. and 6 others. 1995. Increased biological productivity and export production in the glacial Southern Ocean. Nature, 378(6558), 675–680.
Leventer, A., Domack, E. W., Ishman, S. E., Brachfield, 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. Geol. Soc. Am. Bull., 108(12), 1626–1644.
Martin, J. H., Fitzwater, S. E. and Gordon, R. M.. 1990. Iron deficiency limits phytoplankton growth in Antarctic waters. Global Biogeochem, 4(1), 5–12.
Mortlock, R. A. and Froelich, P. N.. 1989. A simple method for the rapid determination of biogenic opal in pelagic marine sediments. Deep-Sea Res., Ser. I, 36(9), 1415–1426.
Mortlock, R. A. and 6 others. 1991. Evidence for lower productivity in the Antarctic Ocean during the last glaciation, Nature, 351(6323), 220–222.
Nunes Vaz, R. and Lennon, G.. 1996. Physical oceanography of the Prydz Bay region of Antarctic waters. Deep-Sea Res., Ser. I, 43(5), 603–641.
Sedwick, P. N. and DiTullio, G. R.. 1997. Regulation of algal blooms in Antarctic shelf waters by the release of iron from melting sea ice. Geophys. Res. Lett., 24(20), 2515–2518.
Shimmield, G. B. 1984. The geochemistry and mineralogy of Pacific sediments. Baja California. (Ph.D. thesis, University of Edinburgh.)
Stuiver, M. and Polach, H. A.. 1977. Discussion: reporting of l4C data. Radiocarbon, 19(3), 355363.
Wedepohl, K. H. 1971. Environmental influences on the chemical composition of shales and clays. In Ahrens, L. H., ed. Physics and chemistry of the Earth. Oxford, Pergamon Press, 307331.
Yang, Y. -L., Elderfield, H., Pedersen, T. F. and Ivanovich, M.. 1995. Geochemical record of the Panama Basin during the last glacial maximum carbon event shows that the glacial ocean was not suboxic. Geology, 23(12), 1115–1118.

A geochemical study of marine sediments from the Mac. Robertson shelf, East Antarctica: initial results and palaeoenvironmental implications

  • P. N. Sedwick (a1), P.T. Harris (a1) (a2), L. G. Robertson (a1), G. M. Mcmurtry (a3), M. D. Cremer (a3) and P. Robinson (a4)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed