Collaborative Research: Paleohistory of the Larsen Ice Shelf System: Phase II

拉森冰架是南极洲第三大冰架，自20世纪90年代中期以来一直在持续灾难性的衰退。拟议中的拉森冰架海洋地质工作建立在我们以前的NSF-1000基金的基础上，并打算测试工作假设，即拉森B冰架系统自10,000年前海平面上升期间形成以来一直是南极洲冰川系统的稳定组成部分。这一结论，如果得到我们拟议工作中观测结果的支持，将是确定半岛目前发生的快速区域变暖的独特性和后果的重要的第一步。我们以前在拉森A和B海湾的工作使我们能够认识到过去冰架波动的特征及其对海洋学和生物环境的影响。我们还克服了标准放射性碳定年法在南极海洋序列中的许多局限性，利用地球磁场强度的变化来进行沉积物记录的相关性，并利用特定的有机化合物（而不是散装沉积物）进行放射性碳定年。我们打算继续推进这些分析进展，并将我们的沉积物岩心地层学扩展到拉森B冰架最近崩塌所发现的地区和拉森C冰架紧邻的地区。除了岩心回收计划外，我们还打算利用我们独特的冰架前缘通道继续观测雪/冰地层学、海洋学特征和海底特征。还将部署沉积物收集器，以测量冰川碎片的输入，这些碎片现在因冰架崩塌而激增。这项建议是一个多机构，国际（USAP，意大利和加拿大）的努力，结合了各种学科的既定专业知识，并将研究计划纳入主要本科院校的教育工作，但包括一些研究生教育。这是一个为期三年的项目，具有灵活的田间季节计划，以适应RVIB L.M.的时间表。 古尔德南极半岛正在经历比地球上几乎任何地方都要严重的变暖，这可能与人类引起的温室效应有关。我们建议的工作有助于了解这些变化首先发生的地方，以及对环境影响最大的地方。

The Larsen Ice Shelf is the third largest ice shelf in Antarctica and has continued a pattern of catastrophic decay since the mid 1990's. The proposed marine geologic work at the Larsen Ice Shelf builds upon our previous NSF-OPP funding and intends to test the working hypothesis that the Larsen B Ice Shelf system has been a stable component of Antarctica's glacial system since it formed during rising sea levels 10,000 years BP. This conclusion, if supported by observations from our proposed work, is an important first step in establishing the uniqueness and consequences of rapid regional warming currently taking place across the Peninsula. Our previous work in the Larsen A and B embayments has allowed us to recognize the signature of past ice shelf fluctuations and their impact on the oceanographic and biologic environments. We have also overcome many of the limitations of standard radiocarbon dating in Antarctic marine sequences by using variations in the strength of the earth's magnetic field for correlation of sediment records and by using specific organic compounds (instead of bulk sediment) for radiocarbon dating. We intend to pursue these analytical advances and extend our sediment core stratigraphy to areas uncovered by the most recent collapse of the Larsen B Ice Shelf and areas immediately adjacent to the Larsen C Ice Shelf. In addition to the core recovery program, we intend to utilize our unique access to the ice shelf front to continue our observations of the snow/ice stratigraphy, oceanographic character, and ocean floor character. Sediment traps will also be deployed in order to measure the input of debris from glaciers that are now surging in response to the ice shelf collapse. This proposal is a multi-institutional, international (USAP, Italy, and Canada) effort that combines the established expertise in a variety of disciplines and integrates the research plan into the educational efforts of primarily undergraduate institutions but including some graduate education. This is a three-year project with field seasons planned with flexibility in order to accommodate schedules for the RVIB L.M. Gould. The Antarctic Peninsula is undergoing greater warming than almost anywhere on Earth, perhaps associated with human-induced greenhouse effects. Our proposed work contributes to understanding of these changes where they are occurring first and with greatest magnitude and impact upon the environment.