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Victoria University Antarctic Research Expedition Science and Logistics Reports 1986-87: VUWAE 31
Modern Sedimentation in Ferrar Fjord, Antarctica
Modern Sedimentation in Ferrar Fjord, Antarctica.
Abstract
The origin of sediment forming the floor of Ferrar Fjord, on the coast of South Victoria Land, Antarctica, has been studied using grain size distribution, composition and shape. The sediment has subequal proportions of mud and sand and a few stones.
Comparison with accessible sources indicates about 25% of the sediment is supraglacial sand and 25% is eolian sand, the remainder being mud whose properties are consistent with those of the fine fraction of basal debris from a wet-based glacier. A process model is proposed whereby sedimentation of mud takes place from turbidity currents, generated by slumping at the grounding line, and density currents, formed by the sinking of hypersaline, supercooled water produced during sea-ice formation. The sedimentation rate is estimated to be about 0.4 mm yr−1.
A facies model, based on the processes considered to be important and which identifies five depositional zones in the present-day fjord, is also presented. This model is considered in conjunction with the recent glacial history of McMurdo Sound and used to infer an origin for the well-sorted sand and sand-mud couplets of CIROS-2 drill core.