Collaborative Research: Tectono-magmatic Controls on the Origin and Evolution of Mid-Ocean Ridge Segmentation at Slow-to-Intermediate Spreading Rates - Top down or bottom up

合作研究：构造岩浆对慢速至中速扩张的大洋中脊分段起源和演化的控制——自上而下或自下而上

• 批准号: 1928804
• 负责人: Garrett Apuzen-Ito
• 金额: $ 31.47万
• 依托单位: University of Hawaii
• 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: 2019-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1928804&HistoricalAwards=false
• 关键词: Collaborative; Research; Tectono; magmatic; Controls

The Earth's surface is divided into a collection of rigid tectonic plates that migrate and interact in response to convection in the underlying mantle. Mid-ocean ridges, the largest volcanic system on Earth, represent plate boundaries where tectonic plates move apart from one another. Ridges are divided into discrete spreading segments, separated by zones of faulting that accommodate varying degrees of strike-slip motion and extension. This project will use state-of-the-art 3-D numerical models to quantify the processes that lead to the formation of these spreading segments and the style of deformation within the offset zones that separate them. The science supported by this research will bolster STEM education in its relevance to a basic understanding of plate tectonics and geohazards. The PIs will give presentations in local K-12 schools and work with high school teachers to create demonstrations that meet specific milestones in physics curricula. The computational code developed through this project will be made available to anyone via the BitBucket public repository. Finally, the international research team with expertise in geology, geophysics, and high-performance computing will ensure that the two graduate students at Boston Colelge and the Univeristy of Hawaii will develop the cross-disciplinary skills needed by the next generation of Earth scientists. Mid-ocean ridge segmentation is the first-order manifestation of plate-tectonics and yet, we still have only a preliminary understanding of the causes for the different forms of segment offsets. This gap in knowledge is largely a result of the fact that the vast majority of prior studies have focused on either lithospheric (top down) or mantle/magma (bottom up) controls, but not both. This study will develop 3-D geodynamic models of a segmented mid-ocean ridge to explore how (i) the fraction of magmatically accommodated extension, M, (ii) segment offset length, and (iii) lithosphere thickness variations, and (iv) fault rheology determine whether the offset between two segments takes the form of a localized transform fault or a zone of more diffuse and variable deformation characteristic of non-transform offsets. Model predictions will be tested and the parameter space refined based on analyses of topography and fault characteristics, including measurements of M, at archetypal transforms and non-transform offsets. Finally, the study will investigate the origin and evolution of mid-ocean ridge segmentation using models that allow the location of magma injection to evolve dynamically and to influence whether adjacent offsets take the form of a non-transform offset or evolves into a transform fault.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.

地球的表面分为一组刚性构造板的集合，这些板板迁移和相互作用，以响应在基础地幔中的对流中。 海脊是地球上最大的火山系统，代表板块边界，构造板彼此分开。 脊分为离散的扩散段，由断层区域隔开，可容纳不同程度的滑滑运动和延伸。 该项目将使用最先进的3-D数值模型来量化导致这些扩展段形成的过程以及将它们分开的偏移区域内的变形风格。这项研究支持的科学将加强STEM教育与对板块构造和地球群的基本理解有关。 PI将在当地的K-12学校进行演讲，并与高中老师合作，​​创建符合物理课程中特定里程碑的演示。通过该项目开发的计算代码将通过Bitbucket公共存储库提供给任何人。最后，具有地质，地球物理学和高性能计算方面具有专业知识的国际研究团队将确保波士顿·科莱尔格（Boston Colelge）的两位研究生和夏威夷大学将发展下一代地球科学家所需的跨学科技能。中海脊分割是板块构造的一阶表现，但是，我们仍然对不同形式的段偏移的原因有初步的理解。知识的差距在很大程度上是由于绝大多数先前的研究都集中在岩石圈（自上而下）或地幔/岩浆（自下而上）控制的结果，但并非两者兼而有之。 这项研究将开发一个分割的中间山脊的3 d地球动力学模型，以探索（i）（i）岩浆可容纳的扩展的比例如何，m，（ii）段偏移长度以及（iii）岩石圈的厚度变化，以及（iv）的（iv）流变学确定两个段之间的偏移是否形成了一个局部变化或更差异的差异，以及一个局部变化的差异和差异的差异，差异是差异的差异和区域。偏移。 将测试模型预测，并根据地形和故障特征的分析（包括M的测量值，原型转换和非转变偏移量）进行测试，并根据形态和故障特性的分析进行了改进。 最后，该研究将使用模型研究中型山脊细分的起源和演变，该模型允许岩浆注入的位置动态发展，并影响相邻的反驳是否采用非转换偏移或发展为变换错误的形式。该奖项反映了NSF的法定任务，并通过评估范围的范围来反映出支持者的范围，并通过评估了基础的范围。