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

地球表面被划分为一系列刚性构造板块，这些板块在底层地幔的对流作用下发生迁移和相互作用。 大洋中脊是地球上最大的火山系统，代表着板块边界，其中构造板块相互分离。 洋脊被分割成离散的扩张段，由断层带分隔，断层带可容纳不同程度的走滑运动和伸展。 该项目将使用最先进的三维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。这项研究所支持的科学将加强STEM教育，使其与板块构造和地质灾害的基本理解相关。 PI将在当地的K-12学校进行演讲，并与高中教师合作，创建符合物理课程特定里程碑的演示。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，拥有地质学、地球物理学和高性能计算专业知识的国际研究团队将确保波士顿学院和夏威夷大学的两名研究生能够发展下一代地球科学家所需的跨学科技能。洋中脊分段是板块构造的一级表现，但对不同形式的分段错断的成因，我们仍只有初步的认识。这种知识上的差距主要是由于这样一个事实，即绝大多数以前的研究集中在岩石圈（自上而下）或地幔/岩浆（自下而上）的控制，但不是两者兼而有之。 本研究将建立分段洋中脊的三维地球动力学模型，以探讨（i）岩浆容纳延伸的比例M，（ii）分段偏移长度，（iii）岩石圈厚度变化，以及（iv）断层流变学如何确定两个分段之间的偏移是否采取局部转换断层的形式，或非转换偏移的更扩散和可变变形特征的区域。 将对模型预测进行测试，并根据对地形和断层特征的分析（包括在原型转换和非转换偏移处的M测量值）对参数空间进行细化。 最后，该研究将利用模型调查大洋中脊分段的起源和演变，这些模型允许岩浆注入的位置动态演变，并影响相邻偏移是否采取非该奖项反映了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进行评估，被认为值得支持的搜索.

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.