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年代中期以来一直延续着灾难性的衰败模式。拟议中的拉森冰架海洋地质工作建立在我们之前的美国国家科学基金会OPP资金的基础上，并打算检验拉森B冰架系统自公元前10000年海平面上升期间形成以来一直是南极冰架系统的稳定组成部分的工作假说。这一结论如果得到我们拟议工作的观察结果的支持，将是确定整个半岛目前正在发生的迅速区域变暖的独特性和后果的重要的第一步。我们之前在拉森A湾和B湾所做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和生物环境的影响。我们还克服了标准放射性碳测年在南极海洋序列中的许多局限性，方法是利用地球磁场强度的变化来对比沉积物记录，并使用特定的有机化合物(而不是大量沉积物)来进行放射性碳测年。我们打算继续取得这些分析进展，并将我们的沉积物岩心地层学扩展到最近一次拉森B冰架坍塌所发现的地区，以及紧邻拉森C冰架的地区。除了岩芯恢复计划外，我们还打算利用我们进入冰架前缘的独特通道，继续我们对冰雪地层、海洋学特征和海底特征的观察。还将部署沉积物捕集器，以测量冰川碎片的输入，目前冰川正在因冰架坍塌而激增。这项建议是一项多机构、国际(USAP、意大利和加拿大)的努力，它结合了各种学科的现有专业知识，并将研究计划整合到主要是本科机构的教育努力中，但也包括一些研究生教育。这是一个为期三年的项目，可以灵活地计划实地考察季节，以适应RVIB L.M.古尔德项目的时间表。南极半岛正在经历比地球上几乎任何地方都更严重的变暖，这可能与人类引发的温室效应有关。我们提议的工作有助于理解这些变化首先发生在哪里，并对环境产生最大的影响和影响。

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.