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Victoria University Antarctic Research Expedition Science and Logistics Reports 1991-92: VUWAE 36


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1. AIMS.

This season we had proposed to run two programmes together; 1.,vibrocorer sampling of the sea floor in Granite Harbour and 2., the study of the Mackay Glacier Tongue Grounding line with a remotely operated submersible vehicle (ROV). At the end of September we postponed the vibrocorer programme because the equipment was not ready and satisfactorily tested but received RDRC permission to continue with the ROV-grounding line study.

Mackay Glacier forms a 3 km wide, 300 m thick, "floating" glacier tongue that moves seaward at 250 ma−1 when it enters Granite Harbour, an embayment up to 900 m deep on th Victoria Land coast. The project is to observe and describe, for the first time, the ineraction between a polar glacier tongue, sediment and sea water at the detachment point (grounding line) using a remotely operated submersible vehicle (ROV).

We propose to study the subglacial delta presumbed to have formed as basal debris carried in the glacial tongue melts out. (Macpherson 1987, Alley et al. 1989). The existence of subglacial deltas and sedimentation processes requires testing to provide better models to compare with seismic data from the Antarctic continental shelf where a number of examples of delta like sedimentary bodies have been observed (Cooper et al. 1990).

The principal objectives for this seasons research are;
1.Determine the character and thickness of the basal debris layer in the glaciers.
2.Evaluate grounding line processes including debris meltout, sediment deformation, meltwater production (if any) and ground line stability.
3.To check if a subglacial delta exists.