Results

Fifty three days of continuously recorded data (15 November – 7 January), was recovered from S4 current meter at the Mackay Glacier Tongue site. Current velocities are low as expected with 10 day averages between 6.9 and 4.3 cm/s and intermittent speeds slightly in excess of 10 cm/s. The dominant flow direction is towards the glacier tongue (240°-270° true) with "daily" swings towards the south that appear to correlate with the main diurnal tide cycle.

At Cape Roberts 50 days of continuous tide data (19 November – 8 January) was recovered giving 48 days of data common between tide gauge and current meter. The tide data shows a dominant diurnal cycle with a maximum measured range of 1.192 m. Neap tides occur approximately every 14 days and are semidiurnal for about two days.

More detailed comparison between the tide record and current meter data is yet to be done but a preliminary comparison suggests a correlation between spring/neap tide cycles and current velocity/direction. However this correlation is out of step by about 2–3 days which is greater than expected and suggests a more complex coupling of tide and circulation within Granite Harbor than first thought.

The eight sediment trap samples showed a much greater "apparent flux" in the bottom four traps below 520 m than in the upper four traps. This result is similar to previous trap data from the inner basin in Granite Harbor and supports the contention that fine-grained sediment is resuspended from near the sea floor in this basin. The current velocities measured this season are certainly capable of maintaining this sediment in suspension. The trap samples will be analysed for opal content and organic carbon by Dr R. Dunbar at Rice University as part of our cooperative program.