Collaborative Research: VeLveT Ice - eVoLution of Fabric and Texture in Ice at WAIS Divide, West Antarctica

1142167/小该奖项支持一个项目，旨在更好地了解冰微结构、杂质和冰流之间的关系，以及它们与西南极冰盖(WAIS)冰核地点气候历史的联系。这项工作建立在西南极Siple Dome和东南极Dome C正在进行的几项研究的基础上。众所周知，在冰盖中，冰的微结构随深度和时间的变化而变化。微结构的这种演变取决于冰流场、温度和杂质含量。反过来，冰流场依赖于微结构，导致反馈导致微结构分层变化，这与气候和流动历史有关。这项研究的重点是更好地理解：1)冰微结构如何随时间和应力在冰盖中演变，以及它与杂质含量、温度和应变率之间的关系；2)冰微结构和杂质含量的变化如何影响冰裂附近的冰流模式(在小尺度(1厘米到1米)和大尺度(1米到100公里)上)；以及3)冰微结构的空间变异性及其对冰流的影响在哪些方面对解释WAIS冰芯的气候历史具有重要意义。这项研究将结合现有的冰芯和钻孔数据，利用电子背向散射衍射(EBSD)技术详细研究冰的微结构，并使用声波遥视器测量钻孔随时间的变形。这将是首次将这两种新技术结合起来研究微结构和变形之间的关系，它将建立在作为其他WAIS Divide钻孔测井项目一部分收集的其他数据的基础上(例如，声速、光学尘埃测井、温度和其他冰芯测量，包括来自薄片分析的组构测量以及冰化学和稳定同位素的研究)。这项工作的学术价值在于，它将改进对冰芯数据的解释(特别是关于过去积累的信息)和对冰流的整体理解。更广泛的影响是，这项工作最终将有助于更好地解释古气候研究和冰流历史的冰芯记录，这两者都与冰在气候系统中的作用这一更广泛的问题有关。这项工作还将促进两名职业生涯早期的女科学家的职业生涯，其中包括一名听力障碍残疾的女科学家。该项目将支持UAF的一名博士生，并为达特茅斯大学的两到三名本科生提供研究和实地经验。PIS计划在他们的现场团队中包括一名教师，并与UAF的“从STEM到STEAM”合作，以加强艺术和科学之间的联系。

1142167/PettitThis award supports a project to develop a better understanding of the relation between ice microstructure, impurities, and ice flow and their connection to climate history for the West Antarctic Ice Sheet (WAIS) ice core site. This work builds on several ongoing studies at Siple Dome in West Antarctica and Dome C in East Antarctica. It is well known that the microstructure of ice evolves with depth and time in an ice sheet. This evolution of microstructure depends on the ice flow field, temperature, and impurity content. The ice flow field, in turn, depends on microstructure, leading to feedbacks that create layered variation in microstructure that relates to climate and flow history. The research proposed here focuses on developing a better understanding of: 1) how ice microstructure evolves with time and stress in an ice sheet and how that relates to impurity content, temperature, and strain rate; 2) how variations in ice microstructure and impurity content affect ice flow patterns near ice divides (on both small (1cm to 1m) and large (1m to 100km) scales); and 3) in what ways is the spatial variability of ice microstructure and its effect on ice flow important for interpretation of climate history in the WAIS Divide ice core. The study will integrate existing ice core and borehole data with a detailed study of ice microstructure using Electron Backscatter Diffraction (EBSD) techniques and measurements of borehole deformation through time using Acoustic Televiewers. This will be the first study to combine these two novel techniques for studying the relation between microstructure and deformation and it will build on other data being collected as part of other WAIS Divide borehole logging projects (e.g. sonic velocity, optical dust logging, temperature and other measurements on the ice core including fabric measurements from thin section analyses as well as studies of ice chemistry and stable isotopes. The intellectual merit of the work is that it will improve interpretation of ice core data (especially information on past accumulation) and overall understanding of ice flow. The broader impacts are that the work will ultimately contribute to a better interpretation of ice core records for both paleoclimate studies and for ice flow history, both of which connect to the broader questions of the role of ice in the climate system. The work will also advance the careers of two early-career female scientists, including one with a hearing impairment disability. This project will support a PhD student at the UAF and provide research and field experience for two or three undergraduates at Dartmouth. The PIs plan to include a teacher on their field team and collaborate with UAF's "From STEM to STEAM" toward enhancing the connection between art and science.