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

Abstract

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.