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，以提高对冰川后退缩和简单海岸地区变薄的理解。研究表明，通过跟踪连续的雷达层，可以在大范围内推断冰芯的年龄-深度关系。通过比较雷达得到的时间尺度和冰流模型得到的时间尺度，推断出了区域尺度上的冰川条件。在simple Coast地区的大部分流间脊上收集了高分辨率雷达剖面，并从simple Dome冰芯中建立了年龄-深度关系。其他人使用的技术的应用是有问题的，因为围绕着简单圆顶的冰流破坏了内层的连续性。该项目的一个具体目标是寻找其他不太直接的方法来匹配未连接剖面之间的雷达层。雷达反射和电导率测量之间的对应关系以及沿着simple Dome岩心的火山硫酸盐将被研究。该策略是在回声中寻找有助于层匹配的独特模式。初步结果令人鼓舞：在simple Dome至少有四个不同的回声可以与电导率剖面的峰值相匹配，其中一个（在2100米深度，约1800年前）的特征与BC山脊约200米的一层非常相似。跨越冰流的匹配层（以及相应的时间尺度）将允许重建简单海岸地区过去流动、变薄和积累速率的空间格局，这是预测南极西部冰盖未来可能变化所需要的。拟议工作所需的数据已经得到；不需要在南极洲进行额外的实地考察。该项目将花费两年时间完成，并将为地球与空间科学的博士生提供核心教育，重点是放射冰川学。

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.