Collaborative Research: Larsen Ice Shelf-A: A Model for Antarctic Ice Shelf-Ocean Dynamics

合作研究：拉森冰架-A：南极冰架-海洋动力学模型

• 批准号: 0003633
• 负责人: Scott Ishman
• 金额: $ 8.6万
• 依托单位: Southern Illinois University at Carbondale
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0003633&HistoricalAwards=false
• 关键词: Collaborative; Research; Larsen; Ice; Shelf

0003633IshmanAbstractThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a collaborative research project between the University of Southern Illinois at Carbondale and the University of New Hampshire. Foraminiferal and stable isotopic analyses of modern sediments and core samples from the Weddell Sea shelf will be used to address the mechanisms underlying the recent collapse of the Larsen Ice Shelf, Antarctica. The Larsen Ice Shelf, located on the northwestern margin of the Weddell Sea along the east side of the Antarctic Peninsula, may be collapsing due to a marked increase in mean annual atmospheric temperature (~+2.5 degrees C) that has resulted in sea-ice free conditions for at least 4 months per year. Alternatively, basal ice shelf melting due to intrusion of relatively warm deepwater may be primarily responsible. From May 6 to June 1, 2000, the Research Vessel Nathaniel B. Palmer (NBP) was used to collect a series of surface sediment grab samples, hydrographic casts, high-resolution seismic data, and gravity cores from a large region of the Weddell Sea shelf formerly covered by the Larsen Ice Shelf-A (LIS-A).Samples collected from surface sediment grabs and gravity cores will be analyzed for foraminiferal distribution (planktonic and benthic; living and dead) data as well as planktonic and benthic foraminiferal oxygen and carbon isotopic analyses (d18O and d13C). Past work has shown a strong correlation between foraminiferal distributions and bottom water masses on the Antarctic continental shelf. Water samples collected from the major water masses in the western Weddell Sea will be measured for their d18O and d13C compositions. The extent of equilibrium d18O and d13C precipitation will be established for selected benthic foraminifers, as well as their d18O and d13C values calibrated to the modern oceanography.The modern foraminiferal distribution and geochemical data will be applied to kasten core and jumbo piston core samples, in addition to other collaborative research, to reconstruct the oceanographic and biotic changes associated with the recent collapse of the LIS-A. The following hypothesis will be tested: That incursions of relatively warm Weddell Deep Water onto the western Weddell Sea shelf has led to the retreat of the LIS-A. The results will contribute to understanding oceanic causal mechanisms for ice shelf collapse and provide a link between Northern Hemisphere climatic and oceanographic change and the Southern Hemisphere. A detailed record of benthic foraminiferal distribution and also planktonic and benthic foraminiferal d18O and d13C will be reconstructed for much of the Holocene in order to determine the natural variability of the LIS and underlying ocean. This work will contribute to detection of anthropogenic forcing of Antarctic ice shelf collapse.

0003633 ishmanabstractthis奖由《极地计划办公室的南极地质与地球物理学计划》提供，支持了南伊利诺伊大学卡宾代尔大学和新罕布什尔大学之间的合作研究项目。对Weddell Sea架的现代沉积物和核心样品的有孔虫和稳定的同位素分析将用于解决南极洲拉尔森冰架最近崩溃的基础机制。拉尔森冰架位于南极半岛东侧的韦德尔海西北边缘，由于平均年度大气温度的显着升高（〜+2.5度C）可能导致每年至少4个月的SEA-ICE自由条件，因此可能崩溃。另外，由于相对温暖的深水侵入而导致的基础冰架融化可能主要是造成的。 From May 6 to June 1, 2000, the Research Vessel Nathaniel B. Palmer (NBP) was used to collect a series of surface sediment grab samples, hydrographic casts, high-resolution seismic data, and gravity cores from a large region of the Weddell Sea shelf formerly covered by the Larsen Ice Shelf-A (LIS-A).Samples collected from surface sediment grabs and gravity cores will be analyzed for foraminiferal分布（浮游生物和底栖动物；活着和死亡）以及浮游和底栖有孔虫的氧和碳同位素分析（D18O和D13C）。过去的工作表明有孔虫分布与南极大陆架上的底水块之间存在很强的相关性。将根据其D18O和D13C组合物测量从西韦德尔海主要水块收集的水样。将建立针对选定的底栖有孔虫的平衡D18O和D13C降水的程度，以及其D18O和D13C值校准为现代海洋学的值。现代有孔虫分布和地球化学数据还将应用于Kasten Core和Jumbo Piston Core Samplass，以及与其他跨性别的研究，以及与其他合作相关联，并将其与其他合作相关联，并将其与其他相关性相关联，并将其与其他相关性相关联。 lis-a。将检验以下假设：将相对温暖的Weddell深水入侵到西韦德尔海架上，导致LIS-A的撤退。结果将有助于理解冰架塌陷的海洋因果机制，并提供北半球气候与海洋学变化与南半球之间的联系。为了确定LIS的自然变异性和下层海洋的自然变异，将重建底栖有孔虫分布以及浮游和底栖有孔虫D18O和D13C的详细记录。这项工作将有助于检测南极冰架塌陷的人为强迫。