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。在对岩心进行处理之前，来自钻孔探测器的数据将立即确定深度与年龄的关系，增强南极地层学的3D制图，帮助搜索南极最古老的冰，并揭示火山或外星尘埃的层层。关于智能优点，定向钻孔测井对于调查冰盖中可能对冰芯年代学、冰流、冰盖物理性质和应对气候变化的稳定性产生影响的特征至关重要。该项目开发的工具和技术在冰川学、生物地球科学和其他行星体的探索中都有应用。该项目旨在更深入地了解气候突然变化的后果和原因。该项目的更广泛影响是，它将包括外展和教育，为学生和博士后提供广泛的培训场地。数据和元数据将通过数据中心和存储库提供，如国家冰雪数据中心门户网站。激光尘埃记录仪探测到亚厘米深度尺度上可重现的古气候特征。尘埃记录仪数据正被用于同步记录和测定非洲大陆上任何地点的年代，揭示积累异常和冰盖快速变薄的事件，并发现特别感兴趣的颗粒层。在这个项目中，我们将部署一台装有磁罗盘的激光尘埃记录仪，以寻找优先定向尘埃的直接证据。使用南极IceCube校准研究的光学散射测量和WAIS Divide的钻孔测井，我们发现了与流动和晶体组构相关的持久各向异性，这表明大多数不溶颗粒一定位于冰粒内。对于十亿分之几的典型浓度，人们对极地冰的多晶结构中杂质的位置知之甚少。虽然可溶杂质通常被认为集中在晶间边界并决定电导率，但不溶颗粒的命运却不那么明朗，显微检查极具挑战性。这些现场钻孔测量将有助于揭示杂质、流动和晶体组构之间的密切关系。该项目的数据将进一步发展独特的南极表面粗糙度记录，作为古风的替代指标，并为理解冰川雷达传播提供新的见解。这个项目在南极洲进行了实地考察。

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.