Aims

The purpose of this project was to determine the nature (speed/direction/persistence) of mud-carrying bottom currents in Granite Harbour. Such currents have been suggested to explain deposits of mud flooring the deeper parts of McMurdo Sound and the basins/harbours along the southern Victoria Land Coast (Barrett et al. 1983, Kelly 1986, Macpherson 1987). There is no single obvious source or depositional process for the mud deposits although Anderson et al. (1984) suggested impinging geostrophic currents and subglacial meltwater as potential sources.

This season's programme (1989-90) was to study the movement of sediment entering Granite Harbour from the Ross Sea by mooring the current meter and sediment traps on the sill between the two main basins of the Harbour. The mooring was to be in place for about 2 months (November - January). We also planned to service the tide gauge at Cape Roberts established in November 1968, and if possible add meteorological instruments to record local climate data for future programmes. Inspection of the tide gauge in January 1989 raised doubts about the permanence of the transducer installation which may not survive ice foot breakout.

A further part of this season's work was related to a future proposal aimed at studying the Holocene Marine Glacial History in this area of the Ross Sea. We intended to carry out a reconnaissance survey of both coastal features in Granite Harbour and nunataks on the south side of the MacKay Glacier to find evidence of Holocene glacier expansion both at sea level and well above the present day MacKay Glacier Tongue grounding line.