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

该奖项支持对拉森盆地第四纪冰川海洋沉积物的合作研究。这些沉积沉积物非常适合研究南极半岛东北部大陆架的现代环境背景和最近的古气候演变，该地区被认为对气候变化表现出明显的敏感性。这些沉积物中的微化石及其稳定的同位素组成提供了变化的海洋条件、冰块范围和沉积物扩散的信息。需要回答的问题包括：1)对冰川作用的动物和同位素反应是什么，包括近端和远端对该地区各种中小型冰块的反应？2)沉积物和地震资料所表示的冰位置的物理证据与其动物和同位素特征之间的关系是什么？3)高度变化的间冰期现代陆架环境模型在多大程度上适用于描述和理解代表不同气候制度的晚第四纪环境？利用表层和岩心沉积物进行的初步研究结果表明，有孔虫组合组成和稳定同位素比值记录了现代和晚第四纪环境条件的高度变化。然而，要重建南极半岛晚第四纪环境史，还需要大量的岩心资料。研究方法包括有孔虫和孢粉分析、有孔虫碳氧同位素比值和碳-14测定。拟建项目为期一年，主要研究目标如下：1)为南极边缘项目在西摩岛近海浅水深度钻井提供首次研究。建议的工作将有助于提供第四纪沉积的良好环境框架，从而解释新生代记录；2)首次建立了南极大陆架沉积物的四三元稳定同位素年代学；3)记录和解释第四纪气候波动，包括提出的全新世变暖事件，因为它们保存在沉积物、生物群和稳定的同位素记录中，并反映了局部和区域冰积聚、物理和化学海洋学以及沉积物源区的变化。本研究是对国际全球变化研究的重要贡献。

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.