PREDICTING AND INVESTIGATING SUBGLACIAL LAKES OF THE FORMER BRITISH AND FENNOSCANDIAN ICE SHEETS

南极冰盖底部存在大型湖泊，这些湖泊可以迅速排干，这一发现与融水的路线和供应有关，因此与冰盖动力学有关。最近的卫星观测表明，冰下湖泊非常活跃，可以在一年或更短的时间尺度上迅速扰乱水系，而在伯德冰川，已经证明了排水和冰流加速之间的直接联系。目前已知有250多个湖泊存在于南极冰盖之下，人们对探索这些冰下环境、寻找生命证据和调查它们作为气候变化长期档案的潜力也越来越感兴趣。美国、俄罗斯和英国牵头的三个旨在钻探这些湖泊的项目证明了这种兴趣。尽管对南极冰下湖泊的研究日益受到重视，但从以前的冰盖中识别和研究古冰下湖泊一直是不可回避的，甚至与其地质特征有关的基本问题也仍然难以捉摸。然而，对古冰下湖泊的调查提供了显著的优势，因为我们拥有关于河床属性的全面信息，它们在后勤方面更容易获得(即步行而不是3公里长的钻探)，我们可以轻松地采样和检查沉积物。如果我能找到古冰下湖泊，那么我就有可能在有关地形背景和水文路径的知识上取得巨大飞跃，这些现象是这些现象的一部分；基本上，我获得了与当代冰下湖泊调查有关的空间和沉积学信息，而失去了短期动态。这项提议提供了一项开创性的研究，旨在通过回答两个主要研究问题来促进对冰下湖泊的研究：(1)我们能否成功地预测和识别前英国和芬诺斯坎迪亚冰盖在上一次冰川期间的冰下湖泊？(2)冰下湖泊对融水路线和供应以及冰盖动力学有什么影响？这项研究将利用地理信息系统和数值冰盖模型来预测前不列颠冰盖和芬诺斯坎迪亚冰盖中可能出现冰下湖泊的位置，然后使用沉积学、地层学和地貌学技术识别和评估其中一些以前的冰下湖泊。制定一套确定古冰下湖泊的诊断标准是该项目的一个主要研究目标，这将是首次尝试这样做。一旦确定，进一步的研究将集中在冰下湖泊和冰盖动力学之间的联系，特别是与融水路线和与冰流的关系有关的联系。预计这项工作和我发现的湖泊的发现将激励许多其他研究人员探索古冰下湖泊的记录，并为冰川学思考基底水如何控制冰通量和路线设定新的议程。

The discovery that large lakes exist at the base of the Antarctic Ice Sheet and that these lakes can rapidly drain has major implications related to meltwater routing and supply and thus ice-sheet dynamics. Recent satellite observations show that subglacial lakes are very active, and can perturb the water system rapidly on annual or shorter time-scales, while at Byrd Glacier a direct link between water drainage and ice flow acceleration has been demonstrated. With over 250 lakes now known to exist under the Antarctic Ice Sheet there has also been rising interest in exploring these subglacial environments to look for evidence of life and to investigate their potential as long-term archives of climate change. This interest is demonstrated by three separate US-, Russian- and UK-led programs which aim to drill into these lakes. Despite the growing importance attached to studying subglacial lakes in Antarctica, the identification and study of palaeo subglacial lakes from former ice sheets has been neglible, with even fundamental questions related to their geological signatures remaining elusive. Yet investigations of palaeo subglacial lakes offers significant advantages because we have comprehensive information about the bed properties, they are logistically more accesable (i.e. on foot instead of 3 km long drills) and we can sample and examine the sediments with ease. If I can find palaeo subglacial lakes then I have the potential to make huge leaps in knowledge with regard to the topographic context and hydrological pathways that the phenomena form a part of; essentially I gain spatial and sedimentological information in relation to contemporary subglacial lake investigations and lose out on the short time dynamics. This proposal offers a pioneering study that aims to invigorate research on subglacial lakes by answering two major research questions: (1) can we successfully predict and identify subglacial lakes of the former British and Fennoscandian Ice Sheets during the last glaciation?; and (2) What impact did subglacial lakes have on meltwater routing and supply and thus ice sheet dynamics? The study will utilise GIS and numerical ice sheet modelling to predict where subglacial lakes may have ocurred in the former British and Fennoscandian Ice Sheets and then the identification and evaluation of some of these former subglacial lakes using sedimentological, stratigraphic and geomorphological techniques. The formulation of a diagnostic set of criteria for identying palaeo subglacial lakes is a major research objective for the project and will be first such attempted. Once identified further research will concentrate on the links between subglacial lakes and ice sheet dynamics, specifically related to meltwater routing and the relationship with ice streams. It is anticipate that findings arising from this work and the lakes I discover will stimulate many other researchers to exploit the record of palaeo subglacial lakes and set a new agenda for glaciological thinking of how basal water exerts a control on ice flux and routing.