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

利用雷达探测的内层和 Siple Dome 的冰芯研究 Siple 海岸的冰川历史

• 批准号: 0229490
• 负责人: Howard Conway
• 金额: $ 27.28万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229490&HistoricalAwards=false
• 关键词: Investigation; Glacial; History; Siple; Coast

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.

该奖项支持一个项目，以提高对冰后期退缩和Siple海岸地区变薄的理解。 研究表明，通过跟踪连续的雷达层，可以在广阔的区域外推冰芯的年龄-深度关系。通过比较雷达得出的时间尺度与冰流模型得出的时间尺度，推断出区域尺度上的冰川状况。 在西普尔海岸地区的大部分河流间山脊上收集了高分辨率的雷达剖面图，并从西普尔圆顶冰芯中建立了年龄-深度关系。 其他人所使用的技术的应用是有问题的，因为围绕Siple Dome的冰流破坏了内部层的连续性。 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的剖面之间的雷达层。将研究雷达反射与电导率测量值和沿着Siple Dome核的火山硫酸盐之间的对应关系。该策略是在回声中搜索有助于层匹配的独特模式。初步结果令人鼓舞：在Siple Dome至少有四个不同的回波可以与电导率剖面中的尖峰相匹配，其中一个（在210米深处，大约1,800年前）的特征与BC山脊上大约200米处的地层非常相似。匹配层（因此，时间尺度）的冰流将允许重建的空间模式，过去的流量，变薄和积累率在西普尔海岸地区，这是需要预测未来可能的变化，南极西部冰盖。拟议工作所需的数据已经具备;不需要在南极洲进行额外的实地工作。该项目需要两年时间完成，将为地球和空间科学博士生提供核心教育，重点是放射冰川学。