10-MONTH OBSERVATION OF THE BOTTOM CURRENT REGIME ACROSS A SEDIMENT DRIFT OF THE PACIFIC MARGIN OF THE ANTARCTIC PENINSULA

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 Penins ula. 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 degrees. The direction of mean flow follows the bathymetric contour, and the m aximum speed never exceeds 20 cm s(-1) (below the typical benthic stor m threshold). The potential temperature is remarkably stable (0.11 +/- 0.01 degrees C and 0.13 +/- 0.02 degrees C at the two sites). The cro ss-covariance indicates a significant peak at 20.2 days lag, slightly longer than the travel time of 18.7 days calculated between the two st ations following the isobaths (98.4 km) and thus providing evidence fo r the topographic control on bottom water flow. The observed bottom wa ter flow is consistent with deposition of Holocene hemipelagic sedimen ts of the 'drift maintenance' stage. Indicators for palaeoceanographic conditions during glacial periods of the 'drift maintenance' stage an d the older 'drift growth' stage are at present too scarce to understa nd fully how the past oceanographic conditions influenced the evolutio n of the drifts.