The south sandwich trench

Abstract

A deep oceanic trench lies east of the South Sandwich Island Arc of the Southern Antilles. Precision echo sounding by U.S.N.S. Eltanin reveals that sediment smoothing in the South Sandwich Trench is only locally perceptible in contrast to the extensive sediment blanketing of the floor of the Puerto Rico Trench. Bottom photographs in the vicinity of the South Sandwich Trench reveal pumice, lapilli, current scour, rock outcrops and, in one instance, ripple marks. Bottom life is generally abundant. The relatively thin sediments of the South Sandwich Arc as inferred from topography and as measured in one reflection profile, stand in sharp contrast to the smooth thick sediment carpet of the Argentine Basin to the north and the Weddell Basin to the south and suggest that the South Sandwich Arc is a young feature.