Marine Evidence for GIS Stability and History of Jakobshavn Isbrae, West Greenland, from the LGM to Holocene

西格陵兰岛雅各布港伊斯布拉 (Jakobshavn Isbrae) 从末次盛冰期到全新世的 GIS 稳定性和历史的海洋证据

• 批准号: 0713755
• 负责人: Anne Jennings
• 金额: $ 34.42万
• 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: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0713755&HistoricalAwards=false
• 关键词: Marine; Evidence; GIS; Stability; History

Intellectual Merit: The Principal Investigators will reconstruct the Late Quaternary-Holocene behavior of Jakobshavns Isbrae (JAKIB) in western Greenland, one of the largest ice streams draining the modern Greenland Ice Sheet (GIS). The period from the Last Glacial Maximum (LGM) to the present will be studied because it involves the most recent large scale change in the mass-balance of the ice sheet, it is the period that will be best preserved in continental shelf sediments, and it is the period for which the highest resolution proxy records of paleo-climate from the Greenland ice cores are available. Given the scale of this ice stream and the size of its associated drainage basin, the investigation will provide information on the Late-Quaternary-Holocene behavior and stability of a major area of the GIS. This research will allow assessment of the links between deglaciation and internal and external environmental controls, such as the influence of inflowing Atlantic Water, and will facilitate modeling of the likely future behavior of the GIS. The Principal Investigators will participate in a research cruise of the British Research Vessel, Sir James Clark Ross, to West Greenland in the late summer of 2007 and collaborate with British colleagues on the post-cruise, interdisciplinary program of laboratory work and modeling. Well-dated, high-resolution sediment records from a transect of sites extending from the shelf edge and along the shelf trough, to sites within Disko Bugt both proximal and distal to the modern ice margin will be acquired on the basis of geophysical data. The hypotheses to test using these cores are:Hypothesis 1: Glacier ice extent and interactions between the West Greenland Currentand the GIS are recorded in the foraminiferal faunas, mineralogical variations, and Sm and Nd isotopic compositions of the sediments.Hypothesis 2: The West Greenland Current has changed in strength, flowpath andwatermass composition from the LGM through the Holocene. These variations haveplayed and continue to play a key role in ice-sheet behavior.Broader Impacts: The underlying rationale for this research is to determine if recent(last ~ 100 yr) observed changes to the mass balance of the GIS reflect natural variabilityin ice sheet dynamics, or if they relate to anthropogenically-induced climate warming.Key to resolving this is an understanding of ice sheet behavior since the LGM andincluding periods in the past near Greenland that were as warm or, even warmer thantoday, such as the middle Holocene optimum. This research will make new discoveriesconcerning the timing and extent of the Greenland Ice Sheet at the LGM on its westernmargin, and the behavior of the JAKIB ice stream during deglaciation, new informationthat will inform paleoceanographers and climate and sea-level modelers. This project is an international effort. It will support a U.S. PhD student, and two undergraduate students. It will involve international student exchanges between the University of Colorado and the United Kingdom. The data acquired will be lodged in the NOAA Paleoclimate Database.

智力优势：主要研究人员将重建格陵兰岛西部的Jakobshavns Isbrae（JAKIB）的晚第四纪-全新世行为，这是现代格陵兰冰盖（GIS）最大的冰流之一。将研究末次盛冰期（LGM）到现在的时期，因为它涉及冰盖质量平衡最近的大规模变化，这是大陆架沉积物保存最好的时期，也是格陵兰冰芯中最高分辨率的古气候代用记录可用的时期。考虑到冰流的规模及其相关流域的大小，调查将提供有关晚第四纪-全新世行为和GIS主要区域稳定性的信息。这项研究将允许冰消作用和内部和外部环境控制之间的联系，如流入大西洋水的影响进行评估，并将促进GIS的未来可能的行为建模。主要调查员将参加英国研究船詹姆斯·克拉克·罗斯爵士于2007年夏末前往西格陵兰的研究巡航，并与英国同事合作进行巡航后的实验室工作和建模的跨学科方案。将根据地球物理数据，从从大陆架边缘和沿着大陆架海槽延伸到迪斯科湾内现代冰缘近端和远端的一系列地点，获取年代久远的高分辨率沉积物记录。假设1：西格陵兰海流与GIS之间的相互作用和冰川覆盖范围记录在有孔虫动物群、矿物学变化和沉积物的Sm和Nd同位素组成中;假设2：西格陵兰海流从末次冰期到全新世在强度、流径和水团组成方面发生了变化。这些变化过去和现在都对冰盖的变化起着关键作用。这项研究的基本原理是确定最近是否（最近~ 100年）观测到的GIS质量平衡变化反映了冰盖动力学的自然变化，或者它们是否与遗传学有关导致气候变暖。解决这个问题的关键是了解自末次冰期以来的冰盖行为，包括过去格陵兰岛附近的时期，这些时期与今天一样温暖，甚至比今天更温暖，如全新世中期的最适期。这项研究将对格陵兰冰盖在其西部边缘的LGM的时间和范围以及JAKIB冰流在冰川消退期间的行为做出新的解释，这些新信息将为古海洋学家和气候和海平面建模者提供信息。这个项目是一项国际努力。 它将支持一名美国博士生和两名本科生。它将涉及科罗拉多大学和联合王国之间的国际学生交流。所获得的数据将存入NOAA古气候数据库。