Putting the West Antarctic Ice Sheet into context

了解南极西部冰盖的背景

• 批准号: 1042728
• 负责人: George Denton
• 金额: $ 37.91万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1042728&HistoricalAwards=false
• 关键词: Putting; West; Antarctic; Ice; Sheet

1042728/DentonThis award supports a project to develop new insights into the cause and pattern of events during the last glacial termination in South America and Antarctica. One emerging view is that a warming Southern Ocean (SO), driven by a chain of events initiated in the Northern Hemisphere (NH) and tied to the interhemispheric climate seesaw of the last termination, was the underlying mechanism that drove the West Antarctic ice sheet (WAIS) from its Late Glacial Maximum (LGM) position back to present-day grounding lines. This ocean thermal forcing would have impacted WAIS by accelerating basal melt rates on fringing floating ice shelves and tongues. The validity of such a proposition can be examined from detailed chronologies of ice retreat at a variety of middle to high latitude sites. From such chronologies, it can be determined whether or not the intervals of ice recession form a pattern that fits the timing of warming pulses known to have occurred in the SO during the termination. The intellectual merit of this project is that it will test the proposition that warming pulses in the SO, driven by NH stadials, are the key events that culminated in recession of WAIS to its present-day configuration, setting up the possibility of irreversible collapse. This test is based on placing into a global context the timing and structure of glacial recession along a transect from the southernmost Andes to the Ross Embayment. This project will examine the middle of the transect, by establishing the chronology of ice recession following the LGM in southernmost South America and on the northern Antarctic Peninsula. Because of the abundance of datable terrestrial organic material in association with glacial deposits ?the most rapid progress will be made by starting in southernmost South America. Specifically, cores will be collected from numerous bogs located between the LGM limit and present-day ice in Cordillera Darwin and on Isla Hoste, and use 14C dates of basal organic remains to develop a chronology for ice recession. The broader impacts of this work include a commitment to education and outreach. This work will educate a graduate student and material from this grant will be used in college courses, as well as in presentations to elementary and middle schools and to senior communities. This proposal does not require field work in the Antarctic.

1042728/Denton该奖项支持一个项目，该项目旨在开发对南美洲和南极洲最后一次冰川终止期间事件的原因和模式的新见解。一种新的观点认为，在北半球(NH)开始的一系列事件的推动下，变暖的南大洋(SO)与上一次冰川终止的半球间气候拉锯有关，是推动西南极冰盖(WAIS)从冰川晚期最大值(LGM)位置回到今天的基准线的根本机制。这种海洋热力将通过加速边缘漂浮冰架和冰舌的基本融化速度来影响WAIS。从各种中高纬度地区冰川退缩的详细年表可以检验这一命题的正确性。根据这样的年表，可以确定冰退缩的间隔是否形成与已知在终止期间已经在SO中发生的升温脉冲的定时相匹配的模式。这个项目的学术价值在于，它将检验一个命题，即由NH基准星驱动的SO中的变暖脉冲是最终导致WAIS衰退到今天的配置的关键事件，从而建立了不可逆转崩塌的可能性。这一测试是基于将从最南端的安第斯山脉到罗斯湾的一条横断面上冰川衰退的时间和结构放在一个全球的背景下进行的。该项目将通过建立南美洲最南端和南极半岛北部末次冰期之后冰川消退的年表来检查样带的中部。由于与冰川沉积有关的丰富的可测年陆地有机物质？从南美洲最南端开始将取得最快的进展。具体地说，岩芯将从位于科迪勒拉达尔文和伊斯拉霍斯特岛LGM界限和现代冰之间的许多沼泽中收集，并使用基础有机遗骸的14C年代来制定冰川衰退的年表。这项工作的更广泛影响包括对教育和外联的承诺。这项工作将教育一名研究生，这笔赠款的材料将用于大学课程，以及在小学、中学和老年社区的演讲中使用。这项提议不需要在南极进行实地工作。