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Ten-month observation of the bottom current regime across a sediment drift of the Pacific margin of the Antarctic Peninsula

Published online by Cambridge University Press:  10 May 2004

Angelo Camerlenghi
Affiliation:
Osservatorio Geofisico Sperimentale, PO Box 2011, 1-34016 Trieste, Italy
A. Crise
Affiliation:
Osservatorio Geofisico Sperimentale, PO Box 2011, 1-34016 Trieste, Italy
C.J. Pudsey
Affiliation:
British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
E. Accerboni
Affiliation:
Osservatorio Geofisico Sperimentale, PO Box 2011, 1-34016 Trieste, Italy
R. Laterza
Affiliation:
Osservatorio Geofisico Sperimentale, PO Box 2011, 1-34016 Trieste, Italy
M. Rebesco
Affiliation:
Osservatorio Geofisico Sperimentale, PO Box 2011, 1-34016 Trieste, Italy

Abstract

We present two time series of bottom current and temperature collected 8 m above the seabed on either side of a large sediment drift located on the continental rise of the Pacific margin of the Antarctic Peninsula. The mean current speed is comparable (6.2 cm s−1 and 6.1 cm s−1 respectively), but the mean direction differs by about 121°. The direction of mean flow follows the bathymetric contour, and the maximum speed never exceeds 20 cm s−1 (below the typical benthic storm threshold). The potential temperature is remarkably stable (0.11 ± 0.01°C and 0.13 ± 0.02°C at the two sites). The cross-covariance indicates a significant peak at 20.2 days lag, slightly longer than the travel time of 18.7 days calculated between the two stations following the isobaths (98.4 km) and thus providing evidence for the topographic control on bottom water flow. The observed bottom water flow is consistent with deposition of Holocene hemipelagic sediments of the ‘drift maintenance’ stage. Indicators for palaeoceanographic conditions during glacial periods of the ‘drift maintenance’ stage and the older ‘drift growth’ stage are at present too scarce to understand fully how the past oceanographic conditions influenced the evolution of the drifts.

Type
Papers—Earth Sciences and Glaciology
Copyright
© Antarctic Science Ltd 1997

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