CSEDI Collaborative Research: Deciphering the LLSVP-plume relationship

CSEDI 合作研究：破译 LLSVP-羽流关系

• 批准号: 1900652
• 负责人: Matthew Jackson
• 金额: $ 9.87万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1900652&HistoricalAwards=false
• 关键词: CSEDI; Collaborative; Research; Deciphering; LLSVP

Much of our view of mantle evolution is shaped by our current knowledge of mantle convection and plume dynamics; examples include hotspot volcanism--including large igneous provinces--and mantle mixing. By gaining a deeper understanding of how, where, and why plumes form, and their composition and their relationship to the deep interior's large low shear wave velocity structures (LLSVPs) under Africa and the Pacific, the PIs will make a significant step towards understanding the dynamical and geochemical evolution of the mantle. Their efforts should provide a basis to better understand the three-dimensional flow structure surrounding LLSVPs and where, how, and why plumes form. This may help answer the question: How is the relationship between plumes and LLSVPs reflected in hotspot lavas such as those found in Hawaii? The new research directions will enrich cross-fertilization between the fields of mantle dynamics and geochemistry and contribute to the growing body of work on mantle plumes and LLSVPs. The PIs are engaged in a number of activities aimed at education and training at all levels. The PIs have and will continue to engage undergraduate students, including those from underrepresented groups in their research activities. As part of this proposal the PIs aim to augment the content associated with related Wikipedia entries and develop a series of educational films to post on specifically dedicated YouTube channels. The lab lends itself to site visits by elementary, middle school and high school students. PI Lithgow-Bertelloni intends to continue providing lab tours and opportunities for elementary and middle-school children to be involved in simple experiments.Amongst the most enigmatic aspects of the Earth's deep interior are the anomalous large low shear wave velocity provinces (LLSVPs) under Africa and the Pacific. The origin, composition, and dynamics of these provinces remain controversial. For example, it has been suggested that plumes predominantly form at the edges of LLSVPs and that entrained material from LLSVPs explains the distinct chemical asymmetries found at certain hotspots. The PIs are proposing an experimental fluid dynamical study to explore how three proposed LLSVP structures control and interact with mantle plumes. These three structures represent the range of LLSVP formation hypotheses so far proposed: a) purely thermal; b) dense and deformable; c) undeformable and uncoupled. They will use state-of-the-art visualization tools, including scanning particle image velocimetry and thermometry to measure the three-dimensional temperature and flow fields, laser induced fluorescence, and Lagrangian analysis tools to locate plumes and quantify entrainment to very high spatial and temporal resolutions. The PIs seek to test both location control and whether entrainment at the edges explains the observed chemical asymmetry in hotspot lavas.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.

我们对地幔演化的大部分看法是由我们目前对地幔对流和地幔柱动力学的了解所决定的。例子包括热点火山活动（包括大型火成岩省）和地幔混合。通过更深入地了解羽流形成的方式、地点和原因，以及它们的组成以及它们与非洲和太平洋下深层内部大型低剪切波速结构 (LLSVP) 的关系，PI 将在理解羽流的方向上迈出重要一步。地幔的动力学和地球化学演化。他们的努力应该为更好地理解 LLSVP 周围的三维流动结构以及羽流形成的地点、方式和原因提供基础。这可能有助于回答以下问题：羽流和 LLSVP 之间的关系如何反映在夏威夷发现的热点熔岩中？新的研究方向将丰富地幔动力学和地球化学领域之间的交叉融合，并为地幔柱和 LLSVP 方面不断增长的工作做出贡献。首席研究员参与了一系列旨在各级教育和培训的活动。 PI 已经并将继续让本科生（包括来自代表性不足群体的学生）参与他们的研究活动。作为该提案的一部分，PI 旨在增强与相关维基百科条目相关的内容，并开发一系列教育影片以发布在专门的 YouTube 频道上。该实验室适合小学生、初中生和高中生实地参观。 PI Lithgow-Bertelloni 打算继续为中小学生提供实验室参观和参与简单实验的机会。地球深处最神秘的部分是非洲地下的异常大型低剪切波速省 (LLSVP)和太平洋。这些省份的起源、组成和动态仍然存在争议。例如，有人认为，羽流主要形成于 LLSVP 的边缘，而 LLSVP 夹带的物质解释了在某些热点发现的明显的化学不对称性。 PI 正在提议一项实验流体动力学研究，以探索所提出的三个 LLSVP 结构如何控制地幔柱并与之相互作用。这三种结构代表了迄今为止提出的 LLSVP 形成假设的范围：a) 纯热； b) 致密、可变形； c) 不变形且解耦。他们将使用最先进的可视化工具，包括扫描粒子图像测速和测温来测量三维温度和流场、激光诱导荧光和拉格朗日分析工具来定位羽流并量化极高空间和时间分辨率。 PI 试图测试位置控制以及边缘夹带是否解释了热点熔岩中观察到的化学不对称性。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Ancient helium and tungsten isotopic signatures preserved in mantle domains least modified by crustal recycling

地幔域中保存的古代氦和钨同位素特征受地壳循环影响最小

• DOI: 10.1073/pnas.2009663117
• 发表时间: 2020-11-23
• 期刊: Proceedings of the National Academy of Sciences
• 作者: M. Jackson;J. Blichert‐Toft;S. Halldórsson;A. Mundl‐Petermeier;M. Bizimis;M. Kurz;A. Price;Sunna Harðardóttir;L. Willhite;K. Breddam;T. Becker;R. Fischer
• 通讯作者: R. Fischer

Trachytic Melt Inclusions Hosted in Clinopyroxene Offer a Glimpse Into Samoan EM2‐Endmember Melts

单斜辉石中的粗面熔体包裹体让我们一睹萨摩亚 EM2 端元熔体的风采

• DOI: 10.1029/2020gc009212
• 发表时间: 2021-03
• 期刊: Geosystems
• 作者: Adams, J. V.;Spera, F. J.;Jackson, M. G.
• 通讯作者: Jackson, M. G.

Mantle plumes and their role in Earth processes

地幔柱及其在地球过程中的作用

• DOI: 10.1038/s43017-021-00168-6
• 发表时间: 2021-05-25
• 期刊: Nature Reviews Earth & Environment
• 影响因子: 42.1
• 作者: A. Koppers;T. Becker;M. Jackson;K. Konrad;R. Müller;B. Romanowicz;B. Steinberger;J. Whittaker
• 通讯作者: J. Whittaker

The Mercury Isotopic Composition of Earth's Mantle and the Use of Mass Independently Fractionated Hg to Test for Recycled Crust

地幔的汞同位素组成以及使用质量独立分馏汞测试再生地壳

• DOI: 10.1029/2021gl094301
• 发表时间: 2021-09-16
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: F. Moynier;M. Jackson;Ke Zhang;Hongming Cai;S. Halldórsson;R. Pik;J. Day;Jiubin Chen
• 通讯作者: Jiubin Chen

Spatial Characteristics of Recycled and Primordial Reservoirs in the Deep Mantle

深部地幔再生与原始储层空间特征

• DOI: 10.1029/2020gc009525
• 发表时间: 2021-03
• 期刊: Geosystems
• 作者: Jackson, M. G.;Becker, T. W.;Steinberger, B.
• 通讯作者: Steinberger, B.