Glacial meltwater evolution during the deglaciation of THE Fennoscandian Ice Sheet

全球气温上升可能会影响冰川融水的生成、分布及其对当代冰块的季节性演变（例如Kingslake等人，2017年）。为了更好地分析这种气候驱动的增加的影响，需要更好地了解融水如何从冰上环境移动到冰下环境及其对冰盖动态和沉积物沉积-侵蚀过程的影响。冰床界面在低估季节性和年度融水演变方面发挥着关键作用-例如，有效和分布式冰下排水系统之间的潜在转换（Andrews等人，2014）。融水可用性的这种变化可以在一系列空间和时间尺度上对冰川物质平衡和冰速提供重要的内部反馈。例如，在加压期间，分布式冰下融水排水系统可能导致冰速度增加。这种冰速度增加的必然结果是，它可能通过增加冰通量，将冰面冰拉到平衡线以下，使更多的冰易于表面融化，并在正反馈中产生更多的融水，从而产生潜在的质量平衡影响。这些过程需要得到充分的理解，以便有效地集成到，或用于测试，数值冰盖models.Given在当代冰床界面观测融水过程中的困难，地质记录可以提供理想的机会，调查过去的冰盖融水演变。该项目探讨了芬兰南部在芬诺斯堪的纳维亚最后一个冰盖消融期间的地质记录。这里提出的工作将利用2米分辨率激光雷达数字地形模型的可用性，以映射密集的网络的eskers及其相关的冰川河流沉积。这些特征可能记录了新仙女木期Salpausselkä冰碛沉积后的融水演变和冰盖排放（Stroeven等人，2016）。这是一个特别重要的时间段，因为它的特点是全球气温上升和随之而来的冰盖退缩，这可能代表了现在的代理。这个案例研究将提供新的细节，如何融水的可用性随时间的变化，以及这是如何与其他代理记录的环境变化。该地图将用于规划一些实地工作活动，以调查最重要的地貌。在这些活动中，学生将收集地球物理数据集，如探地雷达（GPR -频率为50 MHz，100 MHz和160 MHz），电阻率层析成像和地震折射，沿着倾角和走向剖面。这项实地考察还将允许学生收集补充的无人机摄影测量，浅沉积物岩心和基岩样本，用于开发地质年代学，以及可用于地面实况地球物理调查的露头测井和采样。学生将配备在地质和地球物理测量，野外工作规划和数据管理，这将是广泛的潜在的环境，学术和行业职业有用的收集新技能。

Rising global temperatures are likely to lead to an impact on the generation of glacial meltwater, its distribution, and its seasonal evolution on contemporary ice masses (e.g. Kingslake et al., 2017). To better analyse the impacts of this climate-driven increase requires an improved understanding of how meltwater moves from supra- to subglacial settings and its resultant impact on ice sheet dynamics and sediment depositional-erosional processes. The ice-bed interface plays a key role when it comes to understating seasonal and annual meltwater evolution - e.g. potential switches between efficient and distributed subglacial drainage systems (Andrews et al., 2014). Such variations in meltwater availability can provide important internal feedbacks on glacial mass balance and ice velocity across a range of spatial and temporal scales. For example, during episodes of pressurising, a distributed subglacial meltwater drainage system can lead to an increase in ice velocity. The corollary of such an increase in ice velocity is that it could potentially exert a mass balance impact by increasing ice flux, drawing down the ice surface ice below the equilibrium line, making more ice susceptible to surface melting, and generating more meltwater in a positive feedback. These processes need to be robustly understood in order to be effectively integrated into, or used to test, numerical ice sheet models.Given the difficulty in observing meltwater processes at the contemporary ice-bed interface, geological records can provide the ideal opportunity to investigate past ice sheet meltwater evolution. This project explores the geological record of southern Finland during the deglaciation of the last Fennoscandian ice sheet. The work proposed here will exploit the availability of a 2 m resolution LiDAR digital terrain model to map a dense network of eskers and their associated glaciofluvial deposits. These features likely capture a record of meltwater evolution and ice sheet discharge after the deposition of the Salpausselkä moraine during the Younger Dryas (Stroeven et al., 2016). This is a particularly important time period because it is characterised by an increase in global temperature and concomitant ice sheet retreat, that could represent a proxy for the present. This case study will provide new details on how meltwater availability changed through time and how this relates to other proxy records of environmental change. The mapping will be used to plan a number of fieldwork campaigns to survey the most important landforms. During these campaigns the student will collect geophysical datasets, such as ground-penetrating radar (GPR - frequencies of 50 MHz, 100 MHz and 160 MHz), electrical resistivity tomography, and seismic refraction, along dip and strike profiles. This fieldwork will also allow the student to collect supplemental drone-based photogrammetry, shallow sediment cores and bedrock samples for developing a geochronology, as well as outcrop logging and sampling that can be used to ground-truth geophysical surveys. The student will be equipped with new skills in the collection of geological and geophysical surveying, fieldwork planning, and data management that will be useful for wide range of potential environmental, academic, and industry careers.