Pleistocene glaciomarine laminated muds in the Central Basin of the northwestern Ross Sea and their palaeoceanographic records

Abstract

Glaciomarine laminated muds around the Antarctic continental margin are important in the marine geological record related to ice sheet dynamics. Microscopic observation and backscattered electron imagery of Pleistocene laminated muds in the Central Basin (Ross Sea) reveal that the light laminae comprise terrigenous angular to subangular silt-sized particles, scattered diatom fragments, and eroded sand-sized lumps of fossil-bearing mud. In contrast, the dark laminae are clayey and biogenic with very tiny pieces of fossils. These laminated muds are interpreted to have been deposited by subglacial meltwater plumes underneath the advancing glaciers that torn off the earlier-deposited and semi-consolidated diatom-rich sediments. Thus, most biogenic components of these laminated muds were recycled from older deposits, indicating that they are not related to enhanced biological production during the mud deposition. Our study suggests that the recycling of biogenic particles should be considered when interpreting the palaeoclimatic and palaeoceanographic implications of Antarctic environmental system.