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Antarctic Research Series

 

Keywords

  • Ecology—Research—Antarctica—Antarctic Peninsula Region

Index Terms

  • 3022 Marine Geology and Geophysics: Marine sediments—processes and transport
  • 4267 Oceanography: General: Paleoceanography
  • 4207 Oceanography: General: Arctic and Antarctic oceanography
  • 9310 Information Related to Geographic Region: Antarctica

Article

ANTARCTIC RESEARCH SERIES, VOL. 70, PP. 135-154, 1996

Accumulation of glacial marine sediments in fjords of the Antarctic Peninsula and their use as Late Holocene paleoenvironmental indicators

Eugene W. Domack

Department of Geology, Hamilton College, Clinton, New York


Charles E. McClennen

Department of Geology, Colgate University, Hamilton, New York


The five factors that govern glacial marine sedimentation along the western side of the Antarctic Peninsula include proximity to the glacial front, size of glacial drainage basin, sea ice regime, bathymetry, and climate. Glacier-proximal sediments are arenaceous while glacierdistal sediments and those deposited beneath less extensive sea ice are enriched in biogenic constituents. In order to focus upon changing paleoenvironmental conditions over the past several thousand years kasten cores from three fjords were selected for detailed sedimentologic and chronologic study. The three fjords selected for study represent a climate transition from polar to sub-polar climates and thus provide an ideal situation in which to test current models for glacial marine sedimentation. Sediments in Lallemand Fjord (a polar fjord with an ice shelf) accumulate at the rate of 1 to 2 mm yr−1 and are primarily terrigenous. Glacier-proximal deposits record the Late Holocene advance of the Müller Ice Shelf by an increase in eolian sand and a decrease in total organic carbon. Prior to this time, elevated total organic carbon contents in sediments throughout the fjord indicate higher productivity as a consequence of reduced sea ice coverage and a warmer climate. Sediments in Andvord Bay (a sub-polar fjord) are accumulating at the rate of 1.5 to 1.8 mm yr−1 and are enriched in biogenic material (opaline silica and organic carbon) as a consequence of enhanced productivity. Cyclical fluctuations in organic matter preservation as documented in earlier studies were not as well pronounced in these cores but still occur at the time scale of a few centuries. Cores from Brialmont Cove (a sub-polar fjord) are highly variable. Glacier-proximal sedimentation rates are on the order of at least 10–20 mm yr−1. Increased sand deposition and a reduction in total organic carbon took place in Brialmont Cove about 75 years ago and this event is interpreted to represent a several km advance of the tidewater Cayley Glacier. Glacier-distal sedimentation in Brialmont Cove is dominantly biogenic and accumulation rates are on the order of 1 mm yr−1. Characteristic of all fjord cores in the distal setting (>10 km) is a uniform content of ice rafted material indicating that little fluctuation in this component has taken place over the past several thousand years.

Citation: Domack, E. W., and C. E. McClennen (1996), Accumulation of glacial marine sediments in fjords of the Antarctic Peninsula and their use as Late Holocene paleoenvironmental indicators, in Foundations for Ecological Research West of the Antarctic Peninsula, Antarct. Res. Ser., vol. 70, edited by E. E. Hofmann, R. M. Ross, and L. B. Quetin, pp. 135–154, AGU, Washington, D. C., doi:10.1029/AR070p0135.

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