Proposed Program

The purpose of this project is to investigate mud-carrying bottom currents in Granite Harbor. Such currents have been suggested as the explanation for the deposits of mud flooring the deeper parts of McMurdo Sound and the basins/harbors 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.

In the Granite Harbor sedimentary system there is good circumstantial evidence of mud transport in a sea floor nephloid layer Macpherson (1986), Dunbar et al. (1985), Dunbar & Leventer (1987). Macpherson (1987), suggests these currents might be density driven from under the glacier tongue.

This season's program was designed to check on bottom currents originating from beneath the Mackay Glacier Tongue in Granite Harbor. A single current meter/sediment trap mooring was to be set for about 2 months (November – January) at the snout of the Mackay Glacier Tongue. During the 1987–88 season a 14 hour deployment at this site recorded low velocity (<10 cm/s) flows which exhibit progressive changes in direction and duration that appear to be related to the diurnal tide cycle. A tide gauge was also to be established at Cape Roberts initially to record the tide cycle during the period of the current meter deployment and if successful remain to continue recording during the following year.