Anisotropic Ice and Stratigraphic Disturbances

各向异性冰和地层扰动

• 批准号: 1246045
• 负责人: Edwin Waddington
• 金额: $ 24万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2017-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1246045&HistoricalAwards=false
• 关键词: Anisotropic; Ice; Stratigraphic; Disturbances

Waddington/1246045 This award supports a project to investigate the onset and growth of folds and other disturbances seen in the stratigraphic layers of polar ice sheets. The intellectual merit of the work is that it will lead to a better understanding of the grain-scale processes that control the development of these stratigraphic features in the ice and will help answer questions such as what processes can initiate such disturbances. Snow is deposited on polar ice sheets in layers that are generally flat, with thicknesses that vary slowly along the layers. However, ice cores and ice-penetrating radar show that in some cases, after conversion to ice, and following lengthy burial, the layers can become folded, develop pinch-and-swell structures (boudinage), and be sheared by ice flow, at scales ranging from centimeters to hundreds of meters. The processes causing these disturbances are still poorly understood. Disturbances appear to develop first at the ice-crystal scale, then cascade up to larger scales with continuing ice flow and strain. Crystal-scale processes causing distortions of cm-scale layers will be modeled using Elle, a microstructure-modeling package, and constrained by fabric thin-sections and grain-elongation measurements from the West Antarctic Ice Sheet divide ice-core. A full-stress continuum anisotropic ice-flow model coupled to an ice-fabric evolution model will be used to study bulk flow of anisotropic ice, to understand evolution and growth of flow disturbances on the meter and larger scale. Results from this study will assist in future ice-core site selection, and interpretation of stratigraphy in ice cores and radar, and will provide improved descriptions of rheology and stratigraphy for ice-sheet flow models.The broader impacts are that it will bring greater understanding to ice dynamics responsible for stratigraphic disturbance. This information is valuable to constrain depth-age relationships in ice cores for paleoclimate study. This will allow researchers to put current climate change in a more accurate context. This project will provide three years of support for a graduate student as well as support and research experience for an undergraduate research assistant; this will contribute to development of talent needed to address important future questions in glaciology and climate change. The research will be communicated to the public through outreach events and results from the study will be disseminated through public and professional meetings as well as journal publications. The project does not require field work in Antarctica.

Waddington/1246045该奖项支持一个项目，旨在研究Polar Ice Sheets的地层层中褶皱和其他干扰的发作和增长。这项工作的智力优点在于，它将更好地理解控制冰上这些地层特征的谷物规模过程，并将有助于回答诸如哪些过程可以引发这种干扰之类的问题。 雪被沉积在通常平坦的层的极性冰盖上，厚度沿层慢慢变化。 然而，冰芯和冰根化雷达表明，在某些情况下，在转换为冰后，在较长的埋葬之后，这些层可以折叠起来，发展捏式结构（boudinage），并通过冰流进行剪切，范围从厘米到几百米。引起这些干扰的过程仍然鲜为人知。干扰似乎首先在冰结晶尺度上发育，然后随着冰流和应变而级联到更大的尺度。晶体尺度的过程，导致CM尺度层的扭曲，将使用Elle，一个微观结构调制包装进行建模，并受到织物薄段和谷物延长测量的约束，并从南极冰盖西部冰盖除外。与冰塑料进化模型相连的全部压力各向异性冰流模型将用于研究各向异性冰的大量流动，以了解仪表上流动干扰的进化和增长。这项研究的结果将有助于未来的冰核场所选择，并解释冰芯和雷达中地层的解释，并将为冰盖流量流量模型提供改进的流变学和地层的描述。更广泛的影响是，它将对负责地层障碍的冰动力学带来更大的了解。这些信息对于限制冰芯中的深度 - 年龄关系对于古气候研究很有价值。这将使研究人员能够将当前的气候变化放在更准确的环境中。该项目将为研究生提供三年的支持，并为本科研究助理提供支持和研究经验；这将有助于发展冰川和气候变化中重要的未来问题所需的人才。该研究将通过外展活动向公众传达，研究结果将通过公开和专业会议以及期刊出版物传播。该项目不需要在南极洲进行现场工作。