Localised variations in sedimentation characteristics in the Ross Sea and McMurdo Sound regions, Antarctica

Abstract

Sediments have been collected from 24 stations around 3 Glomar Challenger sites in the central southern Ross Sea and from 6 stations in McMurdo Sound. Sediments from the central southern Ross Sea are poorly sorted muds containing variable quantities of sand and gravel; these samples display platykurtic to leptokurtic grain-size distributions. Sediments from McMurdo Sound are much coarser grained, very poorly sorted muddy sands containing an appreciable sand-sized fraction derived from the Ross Island volcanics; these samples display mesokurtic to leptokurtic grain-size distributions. Geochemical studies have shown differences in the trace element composition of the two sets of sediments and refined the broad pattern of trace element distribution in glacio-marine sediments proposed by Angino. Sediments in the central southern Ross Sea contain ice-rafted pebbles; the quantity of pebbles varies over small distances. Studies of the characteristics of these pebbles indicate that they have been eroded during a wet-base glacier regime, and transported subglacially. The probable source of these pebbles is the south-east coast of the Ross embayment.