Marine Test of the Sensitivity of Ice Streams Entering Baffin Bay to Ocean Warming from LGM through Deglaciation, with an Emphasis on Central West Greenland Ice Streams

进入巴芬湾的冰流对末次盛冰期通过冰消作用导致海洋变暖的敏感性的海洋测试，重点是格陵兰岛中西部冰流

• 批准号: 1203492
• 负责人: Anne Jennings
• 金额: $ 37.27万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-15 至 2016-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203492&HistoricalAwards=false
• 关键词: Marine; Test; Sensitivity; Ice; Streams

The proposed research will evaluate how ocean warming contributed to past ice sheet dynamics through study of the Last Glacial Maximum (LGM) through early Holocene behavior of ice streams draining into Baffin Bay. This research will provide a new context for understanding ice sheet response to past warm periods, in particular, the Bølling/Allerod interstadial period, which hosted rapid sea level rise and abrupt climate warming after the LGM. At the LGM the Greenland Ice Sheet (GIS) was one of three large ice sheets terminating via large, fast flowing ice streams into Baffin Bay. This project willstudy the past history, dynamics, and ice-sheet ocean interactions in Baffin Bay, and the role of ocean warming in ice sheet demise, via multi-proxy analysis of existing (2008 and 2009) sediment cores from the West Greenland continental slope. Data from this proposal will be used to model freshwater flux from the ice streams, and will provide new information on what role the Greenland Ice Sheet played in past sea-level rise as the LGM ice sheet began to shed as much as 4.6 m of sea level equivalent. The research will test three hypotheses using foraminiferal faunas, sediment mineralogy, stable isotope analyses, stratigraphy of iceberg rafted detritus (IRD), and visible diffuse spectral reflectance data:1. The western margin of the GIS advanced during stadials and retreated during interstadials inresponse to the presence or absence of ocean warming via the West Greenland Current.2. Peaks of ice-berg rafted material (IRD) result from two distinct processes: Proximal IRD isderived from retreat of the GIS off the shelf edge, whereas distal IRD results from collapse of theLaurentide Ice Sheet and Innutian Ice Sheet/NW Greenland margins in northern Baffin Bay.3. Advection of warm water along the West Greenland margin causes enhanced melting ofnorthern Baffin Bay icebergs and sea ice at the polar front, forming an IRD belt along the W.Greenland margin, which preserves a record of ice sheet-discharge events under conditions ofocean warming. The GIS is losing mass in response to modern warming. It stores enough fresh water to raise global sea level by 6.5 m, making its sensitivity to warming a major societal concern. It is anticipated that the sensitivity and response of the GIS to past warming, which are the foci of this project, will help constrain projections of the future evolution of the GIS.

拟议的研究将通过研究末次盛冰期（LGM）以及流入巴芬湾的冰流的早期全新世行为，评估海洋变暖对过去冰盖动态的影响。这项研究将为了解冰盖对过去的反应提供新的背景。温暖期，特别是伯林/阿勒罗德间质期，末次盛冰期后海平面迅速上升，气候突然变暖，格陵兰冰盖（GIS）是末次盛冰期的三大冰盖之一。该项目将通过对现有的多代理分析，研究巴芬湾过去的历史、动态和冰盖海洋相互作用，以及海洋变暖在冰盖消亡中的作用。 2008年和2009年）来自西格陵兰大陆坡的沉积物岩芯将用于模拟冰流的淡水通量，并将提供有关格陵兰冰盖在过去海平面上升中所扮演的角色的新信息。随着末次海冰盖开始脱落相当于海平面的 4.6 m，该研究将使用有孔虫动物群、沉积物矿物学、稳定同位素分析、冰山漂流碎屑地层学 (IRD) 和可见漫反射光谱数据来检验三个假设。 :1. GIS 的西缘在斯塔迪尔期间前进，在斯塔迪尔期间后退，以响应通过西格陵兰的海洋变暖的存在或不存在Current.2. 冰山漂流物质（IRD）的峰值由两个不同的过程产生：近端IRD源自GIS从陆架边缘的撤退，而远端IRD源自劳伦泰冰盖和因纽特冰盖/西北的崩塌。巴芬湾北部的格陵兰边缘。3. 格陵兰西部边缘的暖水平流导致巴芬湾北部冰山和极地锋面的海冰加速融化，形成了沿西格陵兰边缘的 IRD 地带保存了海洋变暖条件下冰盖排放事件的记录。由于现代变暖，GIS 正在失去质量。它储存的淡水足以使全球海平面上升 6.5 m。使其对变暖的敏感性成为主要的社会问题。预计 GIS 对过去变暖的敏感性和响应是本项目的重点，这将有助于限制对 GIS 未来发展的预测。