Investigation of the Glacial History of the Siple Coast Using Radar-Detected Internal Layers and the Ice Core from Siple Dome

该奖项支持一个项目，旨在提高对西伯利亚海岸地区冰川后退缩和变薄的了解。研究表明，通过跟踪连续的雷达层，冰芯的年龄深度关系可以在大范围内外推。通过将雷达得出的时间尺度与冰流模型得出的时间尺度进行比较，可以推断出区域尺度上的冰川条件。在Siple海岸地区的大多数河流间海脊收集了高分辨率雷达剖面，并从Siple Dome冰芯建立了年龄-深度关系。其他人使用的技术的应用是有问题的，因为环绕Siple Dome的冰流扰乱了内部层的连续性。这个项目的一个具体目标是寻找其他不那么直接的方法来匹配未连接的剖面之间的雷达层。将调查雷达反射与沿Siple Dome核的电导率和火山硫酸盐测量之间的对应关系。其策略是在回波中搜索有助于层匹配的独特模式。初步结果是令人鼓舞的：在Siple Dome至少有四个明显的回波可以与电导率剖面中的尖峰相匹配，其中一个的特征(在210米深，约1800年前)与Ridge BC上约200米处的层非常相似。冰流上的匹配层(因此也是时间尺度)将能够重建Siple海岸地区过去流动、变薄和积累速度的空间模式，这是预测西南极冰盖未来可能发生的变化所必需的。拟议的工作所需的数据已经准备好；不需要在南极洲进行额外的实地考察。该项目将耗时两年完成，将为地球和空间科学博士生提供核心教育，重点是放射性冰川学。

This award supports a project to improve understanding of post-glacial retreat and thinning of the Siple Coast region. Research has shown how age-depth relationships from ice cores can be extrapolated over wide areas by tracking continuous radar layers. By comparing radar-derived timescales with one from a model of ice- flow, glacial conditions over regional scales were inferred. High-resolution radar profiles have been collected across most of the inter-stream ridges in the Siple Coast region, and an age- depth relationship has been established from the Siple Dome ice core. Application of the techniques used by others is problematic because the ice streams that surround Siple Dome have disrupted the continuity of the internal layers. A specific goal of this project is to search for other less direct ways to match radar layers between unconnected profiles. The correspondence between radar reflections and measurements of electrical conductivity and volcanic sulfates along the Siple Dome core will be investigated. The strategy is to search for distinctive patterns in the echoes that will facilitate layer matching. Preliminary results are encouraging: at least four distinct echoes at Siple Dome can be matched to spikes in the conductivity profile and the signature of one (at 210m depth, which is ~1,800 yrs BP) closely resembles that of a layer at ~200m on Ridge BC. Matching layers (and hence timescales) across the ice streams will allow reconstruction of spatial patterns of past flow, thinning and accumulation rate in the Siple Coast region, which is needed to predict future possible changes of the West Antarctic Ice Sheet. Data necessary for the proposed work are already available; additional fieldwork in Antarctica is not required. The project will take two years to complete and will provide core education for a doctoral student in Earth and Space Sciences, with an emphasis on radioglaciology.