Bathymetric distribution of fossil foraminifera within marine sediment cores from the eastern part of Lützow-Holm Bay, East Antarctica, and its paleoceanographic implications

Abstract

Faunal analysis of fossil foraminifera from marine gravity and piston cores collected by the Japanese Antarctic Research Expeditions (1981 and 1992) is used to estimate the impact of the latest Quaternary paleoceanography on coastal environments of the eastern part of Lützow-Holm Bay, East Antarctica.Accelerator Mass Spectrometry (AMS) carbon-14 ages produced from sedimentary organic carbon were less than 16ka (non-corrected). Detailed correlation among submarine cores and Holocene elevated marine deposits exposed on the eastern shore of the embayment is difficult due to the indefinite reservoir correction value for marine organic matter and to upward-increasing abnormal ages for some cores.A local carbonate dissolution level can be delineated around the present depth of 300–400m or shallower in the eastern part of Lützow-Holm Bay during the Holocene, based on distributional trends of arenaceous, calcareous benthic, and planktonic foraminifera recognized within a depth less than 600m. Downcore recovery of calcareous foraminifera containing Bulimina aculeata from two cores obtained in a drowned glacial trough deeper than 600m situated far beyond the dissolution depth of CaCO3 indicates the incursion of warm, high-nutrient, and CaCO3-saturated Circumpolar Deep Water (CDW) from the offshore area along the trough toward the southeastern coast of Lützow-Holm Bay during the Holocene. The intrusion of CDW impacted on the marine environments of the southeastern coast, thereby contributing to peripheral retreat of the ice sheet as well as increasing calcareous benthic foraminiferal productivity along the southeastern coast of Lützow-Holm Bay.