EAR-PF: Unleashing the petrogenetic potential of sanidine using a combined compositional, experimental, and 3D textural approach

Hannah Shamloo博士已获得NSF博士后奖学金，与导师Adam肯特教授一起在俄勒冈州州立大学开展研究和教育计划。这项调查将通过研究喷发岩浆中的矿物来研究产生已知最大火山喷发的过程。开发的工具将有助于准确和定量地解决导致大规模喷发的分区矿物中记录的许多过程。有关岩浆/火山过程的信息，从个别钡（Ba）分区矿物是至关重要的实时火山监测工作的未来爆发。本研究将包括三个部分，（1）定量的天然带透长石的化学特征，从超级火山，（2）进行新的三维结构表征的Ba分带透长石，（3）进行了一系列的实验，在相关条件下，以浅和演化的岩浆系统，以限制Ba和其他微量元素的行为透长石。此外，该教育计划还将为本科生提供与该项目相关的研究机会，提供以STEM中的少数民族为重点的教学机会，并通过社交媒体进行宣传。该调查将更好地解决分区矿物中记录的大规模过程，包括岩体形成，火山爆发的开始和大陆地壳的形成。尽管早在20世纪70年代，透长石和其他碱长石中Ba的分带就已被广泛记录，但由于缺乏基础数据，其作为定量工具的使用受到严重限制，因此，基于Ba分带的假设往往难以验证。本研究将耦合在原位的主要和微量元素表征的天然分区透长石从各种超级火山，使用激光烧蚀ICP-MS和电子显微探针，与三维纹理特征的Ba分区使用高分辨率X射线显微断层扫描。此外，一系列的实验将在相关条件下进行浅和演化的岩浆系统使用冷密封压力容器和非端部加载活塞缸，以量化的分配行为的Ba透长石和玄武岩熔体。这项研究还将开发一种新的技术来研究3D晶体中的化学分区，而不是岩石学中经常使用的传统2D方法，这可能会导致额外的不确定性。更广泛的影响包括为本科生提供研究机会，重点是招募STEM专业的无代表少数民族成员。该项目获得了地球科学部岩石学和地球化学项目的共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Dr. Hannah Shamloo has been granted an NSF EAR Postdoctoral Fellowship to carry out research and educational plans at Oregon State University alongside mentor, Professor Adam Kent. This investigation will examine the processes that produce some of the largest volcanic eruptions known, through the study of minerals present in erupted magmas. The tool developed will help to accurately and quantitively resolve the many processes recorded in zoned minerals that lead to large eruptions. The information for relating magmatic/volcanic processes obtained from individual Barium (Ba) zoning in minerals is critical to the real-time volcano monitoring efforts of future eruptions. This study will consist of three components, (1) quantifying chemical characteristics of natural zoned sanidine from supervolcanoes, (2) perform novel 3D textural characterization of Ba zoning in sanidine, and (3) conduct a series of experiments under relevant conditions to shallow and evolved magmatic systems to constrain the behavior of Ba and other trace elements in sanidine. Additionally, the education plan will entail research opportunities for undergraduates related to this project, teaching opportunities with a focus on minorities in STEM, and outreach via social media.This investigation will better resolve large-scale processes recorded in zoned minerals including pluton formation, initiation of volcanic eruptions, and formation of continental crust. Although the zoning of Ba in sanidine and other alkali-feldspar has been widely documented since at least the 1970’s, its use as a quantitative tool is severely limited by a lack of fundamental data, and as a result, hypotheses based on Ba zoning are often difficult to test. This study will couple in-situ major- and trace-element characterization of natural zoned sanidine from a variety of supervolcanoes using laser ablation ICP-MS and electron microprobe, with 3D textural characterization of Ba zoning using high-resolution X-ray microtomography. Additionally, a series of experiments will be performed under the relevant conditions to shallow and evolved magmatic systems using cold-seal pressure vessels and non-end-loaded piston cylinders to quantify the partitioning behavior of Ba in sanidine and silicic melt. This investigation will also develop a novel technique to study chemical zoning in crystals in 3D rather than the traditional 2D approach often used in petrology that can lead to additional uncertainty. Broader impacts include research opportunities for undergraduate students that will focus on recruiting members of unrepresented minorities in STEM majors. This project received co-funding from the Petrology and Geochemistry program in the division of Earth Sciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.