X-ray and Spectroscopic Studies of Subduction-Related Phases: Probing the Mid-Point of Volatile Recycling in the Earth

俯冲相关相的 X 射线和光谱研究：探测地球挥发性物质循环的中点

• 批准号: 1620423
• 负责人: Quentin Williams
• 金额: $ 37万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1620423&HistoricalAwards=false
• 关键词: ray; Spectroscopic; Studies; Subduction; Related

How the major materials of our hydrosphere and atmosphere, such as water and carbon dioxide, are cycled into the deep Earth within solid mineral phases via plate tectonics, and then ultimately released as fluid phases at high pressures and temperatures, is of key importance for how subduction-associated volcanism (like the circum-Pacific "Ring of Fire") is produced, and also possibly for the occurrence of deep earthquakes (at depths greater than ~200 km). In this project, the investigators plan to examine water- and carbon-containing minerals of relevance under the high-pressure and high temperature conditions under which they release water and carbon dioxide to determine: (1) their properties that govern when water or carbon dioxide are released at depth; and (2) whether water or carbon dioxide are released gradually or abruptly. These results will constrain how the water that ultimately generates circum-Pacific volcanism via water-induced melting is released at depth in the planet, and help in the modeling of magma production at depth; and will explore how carbon dioxide is released at depth and the form in which it might be transported to the surface. Thus, these results have fundamental relevance for the production of volcanism at continental margins, and for how deep subduction-related earthquakes (which are likely greased by fluids) are generated. In conducting these experiments, the group will spearhead the development of a new facility, which will be available to the scientific community as a whole, which is designed to conduct high-pressure/high-temperature characterizations of materials at the Advanced Light Source at Lawrence Berkeley National Labs. The group extensively engages undergraduates in its research effort, and the graduate students supported by this grant include a military veteran. The results are also incorporated into undergraduate curricula at the PI's institution.The investigator team plans to: (1) examine the properties of important carriers of volatiles into Earth's mantle at simultaneous high pressures and high temperatures using high precision single-crystal x-ray diffraction; and (2) characterize the properties of carbonates of relevance to carbonatite petrogenesis at high pressures using infrared and Raman spectroscopy. In tandem with the first objective, the establishment of a new, community-accessible, high-pressure/high-temperature synchrotron-based single crystal x-ray diffraction facility will be facilitated by this support. The cycling of water and carbon dioxide into and out of Earth's interior are pivotal processes that impact both the properties of the solid Earth (through their effects on melting and rheology) and Earth's surface (through the volume of the hydrosphere and the composition of Earth's atmosphere). The team proposes to probe the properties of volatile-bearing phases under subduction conditions to gain insights into: (1) the polymorphism of volatile-bearing phases in Earth's mantle (or, what is degassing at depth); (2) the structures of volatile-bearing phases at high-pressures and temperatures (to examine why these phases hold volatiles); and (3) how phases that are known to carry water to depth (and particularly lawsonite and phengitic micas) behave as they approach (and hopefully exceed) their dehydration conditions. They also will provide new constraints on the rich polymorphism of phases associated with the binding of the carbonate ion under mantle conditions: the focus here will be on alkali-rich carbonates, which have recently been demonstrated to be associated with deep carbonatite melting, and which have largely been uninterrogated at high pressure conditions. The team will utilize this project to deploy two graduate students to assist, work through, shake down and debug a new, world-class high-pressure single-crystal x-ray diffraction set-up that will be set-up and commissioned over the next year at the Advanced Light Source (ALS) at Lawrence Berkeley National Labs (LBNL). This facility will be available to the community as a whole through the General User Program proposal process of the ALS (the facility will also be part of the COMPRES-Consortium's Approved Program at the ALS, and thus will have assistance for users who are awarded time). In addition to this deployment of new community infrastructure, the PI will: (1) contribute to the education of a diverse group of graduate students (currently, one military veteran, one returning female) and undergraduates; (2) continue to publish/contribute to the literature on topics of broad interest for those interested in the natural history of the planet (and promote these as appropriate with press releases); and (3) incorporate new results into UCSC undergraduate teaching (typically, to ~90 earth sciences majors per year).

我们的水圈和大气层的主要物质（例如水和二氧化碳）如何通过板块构造以固体矿物相的形式循环到地球深处，然后最终在高压和高温下以流体相的形式释放出来，对于如何俯冲相关的火山活动（如环太平洋“火环”）的产生，也可能导致深层地震（深度大于 200 公里）的发生。在该项目中，研究人员计划检查在高压和高温条件下释放水和二氧化碳的相关含水和碳矿物，以确定：（1）它们控制水或二氧化碳何时释放的特性在深处释放； (2)水或二氧化碳是逐渐释放还是突然释放。这些结果将限制最终通过水引起的融化产生环太平洋火山活动的水如何在地球深处释放，并有助于对深层岩浆产生进行建模；并将探索二氧化碳如何在深处释放以及它可能以何种形式输送到地表。因此，这些结果对于大陆边缘火山活动的产生以及与深俯冲相关的地震（可能是由流体润滑）如何产生具有根本性的相关性。在进行这些实验时，该小组将带头开发一个新设施，该设施将向整个科学界开放，旨在在劳伦斯的先进光源处对材料进行高压/高温表征伯克利国家实验室。该小组广泛让本科生参与其研究工作，获得这笔资助的研究生包括一名退伍军人。研究结果也被纳入PI所在机构的本科课程中。研究小组计划：（1）使用高精度单晶X射线衍射检查在同时高压和高温下进入地幔的重要挥发物载体的特性; (2) 使用红外和拉曼光谱表征与高压下碳酸岩成岩相关的碳酸盐的性质。与第一个目标相结合，这一支持将有助于建立一个新的、社区可使用的、基于高压/高温同步加速器的单晶 X 射线衍射设施。 水和二氧化碳进出地球内部的循环是影响固体地球特性（通过其对融化和流变学的影响）和地球表面（通过水圈体积和地球大气成分）的关键过程。 ）。研究小组建议在俯冲条件下探测挥发性物质相的性质，以深入了解：（1）地幔中挥发性物质相的多态性（或者说，什么是深部脱气）； (2) 高压和高温下含有挥发物的相的结构（以检查为什么这些相含有挥发物）； （3）已知将水带入深处的相（特别是硬钠石和多云母）在接近（并有望超过）脱水条件时表现如何。 它们还将对地幔条件下与碳酸根离子结合相关的丰富相多态性提供新的限制：这里的重点将是富碱碳酸盐，最近已证明它们与深层碳酸岩熔融有关，并且基本上在高压条件下未经询问。该团队将利用该项目部署两名研究生来协助、研究、完善和调试一个新的、世界一流的高压单晶 X 射线衍射装置，该装置将在明年将在劳伦斯伯克利国家实验室 (LBNL) 的先进光源 (ALS) 进行。该设施将通过 ALS 的一般用户计划提案流程向整个社区开放（该设施也将成为 ALS 的 COMPRES 联盟批准计划的一部分，因此将为获得时间的用户提供帮助）。除了部署新的社区基础设施外，PI 还将：(1) 为多元化的研究生群体（目前为一名退伍军人、一名归国女性）和本科生的教育做出贡献； (2) 继续出版/贡献有关地球自然历史感兴趣的人们广泛感兴趣的主题的文献（并通过新闻稿酌情推广这些文献）； (3) 将新成果纳入 UCSC 本科教学（通常每年约 90 个地球科学专业）。

项目成果

Deformation and Strength of Mantle Relevant Garnets: Implications for the Subduction of Basaltic-rich Crust

与地幔相关的石榴石的变形和强度：对富含玄武质地壳俯冲的影响

• DOI: 10.2138/am-2021-7587
• 发表时间: 2021
• 期刊: American Mineralogist
• 影响因子: 3.1
• 作者: Vennari, C;Lin, F;Kunz, M;Akaogi, M;Miyagi, L;Williams, Q
• 通讯作者: Williams, Q