Next-generation 3D imaging of the on- and off-axis mantle and crustal magmatic systems at the Endeavour segment

Endeavour 段的轴上和离轴地幔和地壳岩浆系统的下一代 3D 成像

• 批准号: 1634786
• 负责人: Douglas Toomey
• 金额: $ 18.11万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1634786&HistoricalAwards=false
• 关键词: Next; generation; 3D; imaging; off

Next-generation 3D imaging of the on- and off-axis mantle and crustal magmatic systems at the Endeavour segmentThe global mid-ocean ridge seafloor spreading system accounts for ~85% of Earth's annual magma budget, dominating the mass and energy exchange between the solid earth and its hydrosphere. Magmatic systems beneath spreading centers drive high- and low-temperature hydrothermal activity that modulates the long-term chemistry of the oceans, hydrates the crust and mantle, supports novel ecosystems whose study has altered our view of the origin of life on Earth, and deposits valuable mineral resources. The fundamental unit of the global mid-ocean ridge system is a ridge segment. Within a single ridge segment there are systematic variations in tectonic, volcanic and hydrothermal processes. Ridge segments vary systematically with spreading rate with three basic types: fast-, intermediate- and slow-spreading. Understanding what governs spreading-center segmentation is to understand the fundamental unit of a globe encircling system. The broader significance and importance of the project will be to use next-generation seismic imaging methods to constrain the structure of the magmatic system beneath a well-studied mid-ocean ridge segment. The study site is located off the west coast of the US and is a focus area for international research with a seafloor observing node as part of Neptune Canada, which is allied with the US Ocean Observatory Initiative. The project will support a junior female researcher and a graduate student as part of the research. There is also significant international collaboration with United Kingdom researchers on innovative new seismic data analysis techniques.Understanding mass and energy transfer at mid-ocean ridges requires mapping mantle and crustal magmatic systems and their relationship to hydrothermal and tectonic processes. The location, size, shape, and longevity of magmatic systems depend on factors such as the patterns of melt delivery from the mantle to the crust, melt ascent pathways, and perhaps most importantly, the efficiency of heat removal. Hydrothermal flow patterns are in turn determined by the distribution of heat sources and crustal permeability. To understand these linkages, the project will more accurately map mantle and crustal magmatic systems at the Endeavour segment both on- and off-axis. The primary objectives are to determine (i) what controls the characteristics and distribution of crustal magma bodies both on- and off-axis, and (ii) how hydrothermal heat transfer interacts with and shapes crustal magmatic systems. These objectives will be accomplished by applying 3D anisotropic travel time tomography and 3D full-waveform inversion (FWI) to wide-angle seismic data from a seismic tomography experiment (ETOMO) at the Endeavour. Segment-scale compressional wave velocity images will be generated to map the distribution of crustal magma bodies, the pattern of melt transport from the shallow mantle through the lower crust, and to infer spatial variations in crustal temperature and melt fraction. The study is sited at the Endeavour Ridge where a wealth of previous results, high-quality seismic data, and recent advances in seismic imaging methods can be brought together at a segment where there are strong contrasts between the segment center and ends.

奋进段的轴上和离轴地幔和地壳岩浆系统的下一代 3D 成像全球洋中脊海底扩张系统约占地球年度岩浆预算的 85%，主导着固体之间的质量和能量交换地球及其水圈。 扩张中心下方的岩浆系统驱动高温和低温热液活动，调节海洋的长期化学反应，使地壳和地幔水合，支持新的生态系统，其研究改变了我们对地球生命起源的看法，并沉积宝贵的矿产资源。 全球洋中脊系统的基本单位是脊段。在单个山脊段内，构造、火山和热液过程存在系统变化。 脊线段随扩张速度而系统地变化，具有三种基本类型：快速扩张、中等扩张和慢速扩张。了解扩散中心分割的控制因素就是了解地球环绕系统的基本单位。该项目更广泛的意义和重要性将是使用下一代地震成像方法来约束经过充分研究的洋中脊部分下方的岩浆系统的结构。 该研究地点位于美国西海岸附近，是国际研究的重点区域，其海底观测节点是加拿大海王星的一部分，与美国海洋观测计划结盟。作为研究的一部分，该项目将支持一名初级女性研究员和一名研究生。还与英国研究人员在创新的新型地震数据分析技术方面开展了重要的国际合作。了解大洋中脊的质量和能量传递需要绘制地幔和地壳岩浆系统及其与热液和构造过程的关系。岩浆系统的位置、大小、形状和寿命取决于多种因素，例如熔体从地幔输送到地壳的模式、熔体上升路径，也许最重要的是排热效率。热液流动模式又由热源分布和地壳渗透性决定。为了了解这些联系，该项目将更准确地绘制奋进段轴上和离轴的地幔和地壳岩浆系统图。主要目标是确定 (i) 是什么控制着轴上和轴外地壳岩浆体的特征和分布，以及 (ii) 热液传热如何与地壳岩浆系统相互作用并塑造地壳岩浆系统。这些目标将通过将 3D 各向异性走时层析成像和 3D 全波形反演 (FWI) 应用于奋进号地震层析成像实验 (ETOMO) 的广角地震数据来实现。将生成分段尺度的压缩波速图像，以绘制地壳岩浆体的分布、从浅地幔到下地壳的熔体传输模式，并推断地壳温度和熔体成分的空间变化。该研究位于 Endeavour Ridge，这里可以将大量先前的结果、高质量的地震数据和地震成像方法的最新进展汇集到一个段，该段的中心和末端之间存在强烈的对比。

项目成果

Seismic Imaging and Physical Properties of the Endeavour Segment: Evidence that Skew Between Mantle and Crustal Magmatic Systems Governs Spreading Center Processes

奋进段的地震成像和物理特性：地幔和地壳岩浆系统之间的偏差控制着扩散中心过程的证据

• DOI: 10.1029/2018gc007978
• 发表时间: 2019-03
• 期刊: Geosystems
• 作者: Arnoux, G. M.;Toomey, D. R.;Hooft, E. E. E.;Wilcock, W. S. D.
• 通讯作者: Wilcock, W. S. D.

Upper Crustal Vp / Vs Ratios at the Endeavour Segment, Juan de Fuca Ridge, From Joint Inversion of P and S Traveltimes: Implications for Hydrothermal Circulation

胡安德富卡海岭奋进段的上地壳 Vp / Vs 比率，来自 P 和 S 走时的联合反演：对热液循环的影响

• DOI: 10.1029/2018gc007921
• 发表时间: 2019-01
• 期刊: Geosystems
• 作者: Kim, Eunyoung;Toomey, Douglas R.;Hooft, Emilie E. E.;Wilcock, William S. D.;Weekly, Robert T.;Lee, Sang‐Mook;Kim, Young Hee
• 通讯作者: Kim, Young Hee

Segmentation of mid-ocean ridges attributed to oblique mantle divergence

地幔倾斜分歧导致的大洋中脊分段

• DOI: 10.1038/ngeo2745
• 发表时间: 2016-08
• 期刊: Nature Geoscience
• 影响因子: 18.3
• 作者: VanderBeek, Brandon P.;Toomey, Douglas R.;Hooft, Emilie E.;Wilcock, William S.
• 通讯作者: Wilcock, William S.

Seismic evidence that black smoker heat flux is influenced by localized magma replenishment and associated increases in crustal permeability: Magma Recharge Governs Heat Flux

地震证据表明黑烟热通量受到局部岩浆补给和相关地壳渗透性增加的影响：岩浆补给控制热通量

• DOI: 10.1002/2016gl071990
• 发表时间: 2017-01
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Arnoux, Gillean M.;Toomey, Douglas R.;Hooft, Emilie E.;Wilcock, William S.;Morgan, Joanna;Warner, Mike;VanderBeek, Brandon P.
• 通讯作者: VanderBeek, Brandon P.

Near-axis crustal structure and thickness of the Endeavour Segment, Juan de Fuca Ridge: Crustal Structure at Endeavour Segment

奋进段的近轴地壳结构和厚度，胡安德富卡海岭：奋进段的地壳结构

• DOI: 10.1002/2016gl068182
• 发表时间: 2016-06
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Soule, Da;Wilcock, William S.;Toomey, Douglas R.;Hooft, Emilie E.;Weekly, Robert T.
• 通讯作者: Weekly, Robert T.