Sedimentology of tunnel valley deposits

隧道谷沉积物的沉积学

• 批准号: RGPIN-2019-06568
• 负责人: Eyles, Carolyn
• 金额: $ 2.19万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754856
• 关键词: Sedimentology; tunnel; valley; deposits

The urbanized regions of Canada are rapidly expanding and there is a growing need to locate, manage and protect sources of drinking water, particularly from groundwater reservoirs (aquifers). However, a major problem facing hydrogeologists trying to locate new sources of groundwater is determining the size and location of units of permeable sediments that host groundwater resources (aquifers) in thick successions of glacial sediment. Recent investigations have shown that many groundwater aquifers are hosted in permeable sediments deposited in large channels (tunnel valleys) that developed beneath the ice sheets that covered northern North America approximately 20,000 years ago. Unfortunately, there is limited understanding of the nature of the sediments infilling these tunnel valleys or their origin. In this proposal I seek funding to investigate the characteristics of tunnel valley sediments in Alaska and Southern Ontario with the aim of better understanding their sedimentological record and evolution. Enhanced understanding of the sedimentology of tunnel valley deposits is essential for future groundwater exploration and management in Canada. The proposed research will investigate the infills of tunnel valleys in two settings: the coastal region of Alaska where the late Cenozoic Yakataga Formation is well exposed, and in southern Ontario where surface exposures and borehole data through Pleistocene tunnel valley deposits are available. These sites were chosen because both locations provide exceptional, and accessible, exposures through tunnel valley deposits on extensive wave cut platforms and in vertical cliff sections on a scale unmatched anywhere in the world. Research will be conducted using an innovative `landsystems' approach that integrates examination of glacial landforms with the sediments underlying them. The research proposed here involves initial identification and mapping of tunnel valley features at sites in Alaska and Southern Ontario from satellite imagery; these maps will then guide field investigations of landforms and outcrops using standard sedimentological techniques that document grain size, sedimentary structures, and unit geometries. We will also use an unmanned aerial vehicle (UAV/drone) to collect high resolution imagery of sediment exposed on wave cut platforms and in cliff exposures. All of these data will be used to develop new depositional models for tunnel valley systems that will enhance the prediction of groundwater movement in these deposits. This research will greatly benefit Canada by enhancing our understanding of glacial sediments and their influence on the movement of groundwater, and will aid in the exploration for, and management of, groundwater resources. This research will also involve the training of at least 6 new graduate HQP's and 10 undergraduates and is significant given the anticipated shortage of skilled professional geoscientists in Canada.

加拿大的城市化地区正在迅速扩大，越来越需要确定、管理和保护饮用水源，特别是来自地下水库（含水层）的饮用水源。然而，水文地质学家在寻找新的地下水来源时面临的一个主要问题是确定在厚厚的冰川沉积物序列中承载地下水资源（含水层）的渗透性沉积物单元的大小和位置。最近的调查表明，许多地下水含水层都是在大约2万年前覆盖北美北部的冰盖下形成的大通道（隧道谷）中沉积的可渗透沉积物中。不幸的是，人们对填充这些隧道山谷的沉积物的性质及其起源的了解有限。在这项提案中，我寻求资助，以调查阿拉斯加和南安大略隧道山谷沉积物的特征，以便更好地了解它们的沉积记录和演化。加强对隧道谷沉积物沉积学的了解对加拿大未来的地下水勘探和管理至关重要。拟议的研究将在两个环境中调查隧道山谷的填充物：阿拉斯加沿海地区，晚新生代Yakataga组暴露良好，安大略省南部，地表暴露和更新世隧道山谷沉积物的钻孔数据可用。之所以选择这两个地点，是因为这两个地点都提供了独特的、可访问的、通过隧道山谷沉积物在广泛的波浪切割平台和垂直悬崖部分的暴露，其规模在世界上任何地方都无法比拟。研究将使用一种创新的“陆地系统”方法进行，该方法将对冰川地貌及其下面的沉积物进行综合检查。这里提出的研究包括从卫星图像中初步识别和绘制阿拉斯加和安大略南部地区的隧道谷特征；然后，这些地图将指导地貌和露头的实地调查，使用标准的沉积学技术记录颗粒大小、沉积结构和单位几何形状。我们还将使用无人驾驶飞行器（UAV/drone）收集暴露在切割平台和悬崖上的沉积物的高分辨率图像。所有这些数据将用于开发新的隧道山谷系统沉积模型，这将加强对这些沉积物中地下水运动的预测。这项研究将大大有利于加拿大，因为它加强了我们对冰川沉积物及其对地下水运动的影响的了解，并将有助于勘探和管理地下水资源。这项研究还将涉及至少6名新的HQP研究生和10名本科生的培训，鉴于加拿大预计缺乏熟练的专业地球科学家，这项研究具有重要意义。