Doctoral Dissertation Research: A Comparison of the Holocene Extents of the Greenland Ice Sheet in Western and Eastern Greenland

博士论文研究：格陵兰西部和东部格陵兰冰原全新世范围的比较

• 批准号: 1128909
• 负责人: Meredith Kelly
• 金额: $ 1.2万
• 依托单位: Dartmouth College
• 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 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1128909&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Comparison; Holocene

The Arctic is currently warming more rapidly than other locations on the planet and the response of the Greenland Ice Sheet to this warming is a focus of many current studies. Model projections of the contribution of the Greenland Ice Sheet to global sea level rise range from 4.5 to 17 cm by 2100. This project will help to understand the possible response of the Greenland Ice Sheet to future warming by developing records of the ice sheet margin during past warm times particularly during recent interglacial period (the Holocene Epoch, 11,650 years B.P. to present). The research will focus on the Kangerlussuaq region (67.0N, 50.7W) in western Greenland where a record of ice margin extents during the Holocene is marked by belts of prominent, well-preserved moraine ridges. Preliminary ages of moraines, determined by surface-exposure dating using the cosmogenic nuclide Beryllium-10, demonstrate the ability to date precisely the moraines near Kangerlussuaq. Results from one set of moraines, the ?Orkendalen moraines?, located just outboard of (and in some places adjacent to) the historical moraines, indicate that the Greenland Ice Sheet was smaller than at present between ~6,500 years ago and the historical advance culminating in A.D. 1850. The project will develop a chronology of the Greenland Ice Sheet margin fluctuations near Kangerlussuaq using a combination of detailed geomorphic mapping and surface-exposure dating of moraines. Ice sheet margin fluctuations will be compared with Holocene records of insolation, ocean circulation and surface air temperatures to examine the possible climate mechanisms that may have influenced the fluctuations of Holocene ice extent in eastern Greenland. The timing and spatial continuity of these fluctuations will provide insight into how the Greenland Ice Sheet will respond to future climate changes. This research will produce the first directly dated ice margin chronology in the Kangerlussuaq region in Greenland. Ice cores from the Greenland Ice Sheet register temperature, dustiness and other atmospheric conditions over the ice sheet, but do not provide information on how the sensitive margins of the ice sheet have changed. Combined with data from eastern Greenland, this new record from western Greenland will provide a geographically broad, spatial comparison of ice margin fluctuations that will be useful for testing hypotheses of climate mechanisms that cause ice sheet variability.As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.

北极目前比地球上其他地方变暖更快，格陵兰冰盖对这种变暖的反应是目前许多研究的重点。模型预测，到2100年，格陵兰冰盖对全球海平面上升的影响将在4.5至17厘米之间。 该项目将通过对过去温暖时期，特别是最近间冰期（全新世，距今11 650年）冰盖边缘的记录，帮助了解格陵兰冰盖对未来变暖的可能反应。 这项研究将集中在格陵兰岛西部的Kangerlussuaq地区（67.0N，50.7W），那里记录了全新世期间的冰缘范围，以突出的，保存完好的冰碛脊带为标志。冰碛石的初步年龄，确定表面暴露测年使用宇宙成因核素铍-10，证明有能力精确测年附近的Kangerlussuaq冰碛石。 结果从一组冰碛，？奥肯达伦冰碛？，位于历史冰碛物的外侧（在某些地方邻近），表明格陵兰冰盖在大约6,500年前和公元1850年达到顶峰的历史进步之间比现在小。该项目将结合详细的地貌测绘和冰碛物的表面暴露年代测定，编制一份Kangerlussuaq附近格陵兰冰盖边缘波动年表。 冰盖边缘的波动将与全新世的日照、海洋环流和地表气温记录进行比较，以研究可能影响格陵兰东部全新世冰层范围波动的气候机制。这些波动的时间和空间连续性将有助于了解格陵兰冰盖将如何应对未来的气候变化。 这项研究将产生格陵兰Kangerlussuaq地区第一个直接定年的冰缘年表。 来自格陵兰冰盖的冰芯记录了冰盖上的温度、灰尘和其他大气条件，但没有提供有关冰盖敏感边缘如何变化的信息。 结合格陵兰岛东部的数据，格陵兰岛西部的这一新记录将提供一个地理上广泛的冰缘波动的空间比较，这将有助于测试导致冰盖变化的气候机制的假设。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生能够建立一个强大的独立研究事业。