Collaborative Research: Quaternary Paleoenvironmental Evolution of the Larsen Basin, Offshore Seymour Island, Eastern Antarctic Peninsula

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Abstract This award supports a collaborative study of Quaternary glacial marine deposits of the Larsen Basin. These sedimentary deposits are uniquely suited for study of the Modern environmental setting and recent paleoclimatic evolution of the northeastern Antarctic Peninsula continental shelf, an area thought to exhibit pronounced sensitivity to climatic changes. Microfossils from these deposits and their stable isotope compositions provide information on varying oceanographic conditions, ice mass extent, and sediment dispersal. Questions to be answered include: 1) What are the faunal and isotopic responses to glaciation, both proximal and distal to the variety of small and medium ice masses in the area? 2) What is the relationship between physical evidence of ice position, as expressed in sediments and seismic data, and the faunal and isotopic signatures thereof? 3) To what extent is an environmental model of the highly variable interglacial Modern shelf applicable to describing and understanding late Quaternary environments representative of different climatic regimes? Preliminary results of a pilot study using surface and cored sediments indicate that foraminiferal assemblage composition and stable isotope ratios record highly variable Modern and late Quaternary environmental conditions. However, data are needed from a larger number of cores to reconstruct the Antarctic Peninsula late Quaternary environmental history. Methods to be employed in this research are foraminiferal and palynological analyses, foraminiferal carbon and oxygen isotope ratios, and carbon-14 measurements. The primary research objectives of the proposed one-year project are as follows: 1) Provide the first study for the Antarctic Margin Project for drilling in shallow water depths offshore of Seymour Island. The proposed work would serve to provide a sound environmental framework of the Quaternary deposits from which to interpret the Cenozoic record; 2) Establish the first Qua ternary stable isotope chronostratigraphy for Antarctic continental shelf sediments; 3) Document and interpret Quaternary climatic fluctuations, including proposed Holocene warming episodes, as they are preserved in the sediments, biota, and stable isotopic records, and reflect variations in local and regional ice buildup, physical and chemical oceanography, and sediment source areas. This research represents an important contribution to international global change studies.