Late Quaternary Dynamics of the Labrador/Foxe Sectors of theLaurentide Ice Sheet and Ice-Sheet/Ocean Interaction in the North Atlantic

北大西洋劳伦泰冰盖拉布拉多/福克斯扇区的晚第四纪动力学及冰盖/海洋相互作用

• 批准号: 9005179
• 负责人: Gifford Miller
• 金额: $ 25.5万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1995-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9005179&HistoricalAwards=false
• 关键词: Late; Quaternary; Dynamics; Labrador; Foxe

The demonstration of a major advance from a Labradorean dispersal center flowing essentially at right angles to regional topographic features, and that overtopped Loks Land despite an unconstrained margin facing the open ocean to the SE, provides strong evidence that the flux of ice during this advance must have been great. The cross-sectional area for that portion of the ice facing the Labrador Sea is ca. 300 km2. Assuming a velocity between that of Jacobshavn Glacier, an outlet glacier draining the Greenland Ice Sheet (8 km a-1), and the Ross Ice Shelf, Antarctica (1 km a-1) yields an annual flux of 300 to 2400 km3 a-1. This is about the same fresh-water flux entering the North Atlantic when the St Lawrence outlet was opened by the retreating Laurentide Ice Sheet 11,000 years ago (30,000 m3 sec-1 or 1000 km3 a-1; Teller, 1988). Recognizing the importance of ice-sheet/ocean interactions in the global climate system, we are proposing a research campaign to include a new field effort to define more precisely the spatial limits of this newly recognized advance, and the timing of its onset and retreat, and to model the ice dynamics based on the field evidence. Specifically, we intend to address five objectives: 1) Defining the maximum limits of the Labradorean advance; 2) Deciphering the interaction between the Foxe outlet glacier the flowed out Frobisher Bay and the Labradorean ice sheet backfilling the bay; 3) Determining whether all of Meta Incognita Peninsula was over-ridden by Labradorean ice; 4) Defining the temporal limits of these advances; and using the field evidence on the limits and timing of ice sheet advance and retreat as input to glaciological models to provide realistic ice limits, and ice velocities. Accurate reconstructions of the overall configuration of the Laurentide Ice Sheet and the pattern of its flow are necessary to understand the climate and general circulation during a glaciation, the response of the earth's crust to loading, and contribute to our understanding of ice dynamics.

从拉布拉多扩散中心到区域地形特征基本上成直角流动的重大进展的演示，以及尽管面对开阔海洋的无限制边缘到东南部的泛滥的罗克斯陆，提供了强有力的证据，表明在这种推进过程中冰的流量一定很大。面对拉布拉多海的那部分冰的横截面积约为300平方公里。假设雅各布港冰川的流速介于排干格陵兰冰盖(8公里a-1)和南极洲罗斯冰架(1公里a-1)的出口冰川之间，年通量为300至2400公里m~3 a-1。这与11,000年前退缩的劳伦德冰盖打开圣劳伦斯出口时进入北大西洋的淡水流量大致相同(30,000立方米秒-1或1000千米3秒-1；泰勒，1988年)。认识到冰盖/海洋相互作用在全球气候系统中的重要性，我们提议开展一项研究活动，以包括一项新的实地努力，以更准确地界定这一新认识的进动的空间界限，以及其开始和后退的时间，并根据实地证据对冰动力学进行模拟。具体地说，我们打算解决五个目标：1)确定拉布拉多雷冰进的最大限度；2)破译Frobisher湾流出的福克斯出口冰川和回填海湾的拉布拉多冰盖之间的相互作用；3)确定整个米塔因科尼塔半岛是否被拉布拉多冰盖盖；4)确定这些推进的时间界限；并使用关于冰盖进退的界限和时间的现场证据作为冰川学模型的输入，以提供真实的冰限和冰速度。准确重建Laurentide冰盖的整体形状及其流动模式对于了解冰川期间的气候和大气环流、地壳对载荷的响应以及有助于我们理解冰动力学是必要的。