Laser Dust Logging of a South Pole Ice Core

Bay/1443566该奖项支持在南极冰芯钻孔中部署和分析定向激光粉尘记录仪的数据，以补充冰芯记录的研究。 在处理岩芯之前，钻孔探测器的数据将立即确定深度-年龄关系，增强南极地层的3D绘图，帮助寻找南极洲最古老的冰，并揭示火山或外星沉降物的层。 关于知识价值，定向钻孔测井对于调查冰盖中可能对冰芯年代学、冰流、冰盖物理特性和稳定性对气候变化的反应产生影响的特征至关重要。 该计划开发的工具和技术可应用于冰川学、地球科学和其他行星体的探索。该计划旨在更深入地了解气候突然变化的后果和原因。该项目更广泛的影响是，它将包括推广和教育，为学生和博士后提供广泛的培训基础。 数据和元数据将通过国家冰雪数据中心门户网站等数据中心和存储库提供。激光尘埃记录仪在亚厘米深度尺度上检测可再现的古气候特征。 灰尘记录仪的数据正被用于同步记录和确定大陆上任何地点的年代，揭示积累异常和冰盖快速变薄的情况，并发现特别感兴趣的微粒层。 在这个项目中，我们将部署一个配备磁罗盘的激光粉尘记录仪，以找到优先定向粉尘的直接证据。 使用光学散射测量冰立方校准研究在南极和钻孔日志在WAIS分水岭，我们已经检测到一个持久的各向异性相关的流量和晶体结构，这表明大多数不溶性微粒必须位于冰粒。 由于典型的浓度为十亿分之一，人们对极地冰多晶结构中杂质的位置知之甚少。 虽然可溶性杂质通常被认为集中在晶界并决定电导率，但不溶性颗粒的命运却不太清楚，显微镜检查极具挑战性。 这些现场钻孔测量将有助于解开杂质，流动和晶体结构之间的密切关系。 该项目的数据将进一步开发南极表面粗糙度的独特记录，作为古风的代理，并为理解冰川雷达传播提供新的见解。 这个项目在南极洲有实地工作。

Bay/1443566This award supports the deployment and analysis of data from an oriented laser dust logger in the South Pole ice core borehole to complement study of the ice core record. Before the core is even processed, data from the borehole probe will immediately determine the depth-age relationship, augment 3D mapping of South Pole stratigraphy, aid in searches for the oldest ice in Antarctica, and reveal layers of volcanic or extraterrestrial fallout. Regarding the intellectual merit, the oriented borehole log will be essential for investigating features in the ice sheet that may have implications for ice core chronology, ice flow, ice sheet physical properties and stability in response to climate change. The tools and techniques developed in this program have applications in glaciology, biogeoscience and exploration of other planetary bodies. The program aims for a deeper understanding of the consequences and causes of abrupt climate change. The broader impacts of the project are that it will include outreach and education, providing a broad training ground for students and post-docs. Data and metadata will be made available through data centers and repositories such as the National Snow and Ice Data Center web portal. The laser dust logger detects reproducible paleoclimate features at sub-centimeter depth scale. Dust logger data are being used for synchronizing records and dating any site on the continent, revealing accumulation anomalies and episodes of rapid ice sheet thinning, and discovering particulate horizons of special interest. In this project we will deploy a laser dust logger equipped with a magnetic compass to find direct evidence of preferentially oriented dust. Using optical scattering measurements from IceCube calibration studies at South Pole and borehole logs at WAIS Divide, we have detected a persistent anisotropy correlated with flow and crystal fabric which suggests that the majority of insoluble particulates must be located within ice grains. With typical concentrations of parts-per-billion, little is known about the location of impurities within the polycrystalline structure of polar ice. While soluble impurities are generally thought to concentrate at inter-grain boundaries and determine electrical conductivity, the fate of insoluble particulates is much less clear, and microscopic examinations are extremely challenging. These in situ borehole measurements will help to unravel intimate relationships between impurities, flow, and crystal fabric. Data from this project will further develop a unique record of South Pole surface roughness as a proxy for paleowind and provide new insights for understanding glacial radar propagation. This project has field work in Antarctica.