CAREER: Moving into the 3rd Dimension: Quantifying the influence of Magmatism, Tectonics, Hydrothermal Cooling, and Hotspots on the Dynamic Evolution of Divergent Plate Boundaries

板块构造理论认为，地球表面是由许多移动的板块组成的。这些板块的内部区域被认为是坚硬而坚固的，而板块分开的海洋边界，大洋中脊，是薄的、热的和脆弱的。与板块构造理论的标准预期相反，观察发现，大洋中脊的部分经常从薄弱的边界转移或跳跃到强大的板块内部。因此，大洋中脊的跳跃可以改变构造板块的大小和形状，甚至在它们跳入大陆地区时形成微大陆(大陆物质的小碎片)。大洋中脊的跳跃被认为是在一些过程削弱了附近的板块内部之后产生的。然而，科学家们并不知道这种减弱背后的原因或驱动力。以前的研究考察了2D几何学中的大洋中脊跳跃，但无法解决控制它们形成的几个关键过程，这给我们对板块构造的理解留下了空白。在这项研究中，创新的实验室和最先进的3D数值模拟将被用来分离导致大洋中脊跳跃的过程。了解这些过程将增进对地球的热演化以及与过去的热液活动有关的潜在矿产资源位置的了解。这个职业奖项的教育部分有两个主要目标：1)通过互动的、基于海洋地质学的视频游戏，激励年轻学生(~10-18岁)进行基于STEM的研究，这些游戏引人入胜，具有娱乐性，并为深入探索海洋地质主题提供容易获得的机会；2)让几个跨学科的本科生小组参与实践，参与他们学习STEM技能和探索海洋地质数据的体验。对许多遗迹扩散中心和由突然搬迁或脊轴跳跃形成的微洲的观察表明，大洋中脊经常跳跃到新的、偏离轴线的位置。该项目的主要研究目标是量化控制脊跳的过程，从而检验存在可预测的脊跳形成的长度和时间尺度的假设。这一目标分为三个目标，旨在量化：1)岩浆吸积在与已建立的海脊相邻的新生裂谷的传播中所起的作用，以及由此形成的转换断层或重叠的扩展中心；2)地幔羽流在大洋岩石圈引起的脊跃；以及3)通过跳跃进入大陆岩石圈形成微大陆。这些目标将通过使用胶体流体的3D数值模拟和创新的实验室实验来实现。为了从这些模型和实验中建立可检验的预测，结果将被用来推导脊跃跃的长度和时间尺度与可观测量之间的函数关系，如扩散速度、脊移移速率、海底年龄和熔体流量。这些关系将通过与新的跳跃统计数据库进行比较来评估，包括跳跃距离、最终节段长度、转换断层或重叠传播中心形成率和位置，以及重复跳跃之间的时间。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The theory of plate tectonics states that the surface of the Earth is made up of numerous moving plates. The interior regions of these plates are believed to be rigid and strong, while boundaries in the ocean where the plates spread apart, mid-ocean ridges, are thin, hot, and weak. In contrast to the standard expectations of plate tectonic theory, observations find that sections of mid-ocean ridges often shift, or jump, from weak boundaries to strong plate interiors. As a result, jumps of mid-ocean ridges can change the size and shape of the tectonic plates and even create micro-continents (small slivers of continental material) when they jump into continental regions. Mid-ocean ridge jumps are believed to result after some process weakens a nearby plate interior. However, scientists do not know the reasons or driving forces behind this weakening. Previous studies examined mid-ocean ridge jumps in a 2D geometry, but could not address several key processes that would control their formation, leaving a gap in our understanding of plate tectonics. In this study, innovative laboratory and state-of-the-art 3D numerical simulations will be used to isolate the processes that lead to mid-ocean ridge jumps. Understanding these processes will improve understanding of the thermal evolution of the planet and the locations of potential mineral resources associated with past hydrothermal activity. The educational component of this CAREER award has two primary goals: 1) to motivate young students (~10-18 years old) to pursue STEM-based inquiry through interactive, marine geology-based video games that are engaging, entertaining, and provide easily accessible opportunities for in-depth exploration of marine geology topics, and 2) to involve several interdisciplinary groups of undergraduate students in a hands-on, engaging experience where they learn STEM skills and explore marine geologic data.Observations of numerous relic spreading centers and micro-continents formed by sudden relocations or jumps of ridge axes indicate that mid-ocean ridge jumps regularly shift to new, off-axis locations. This project's primary research goal is to quantify the processes that govern ridge jumps and thereby test the hypothesis that there are predictable length- and time-scales for ridge jump formation. This goal is split into three objectives that aim to quantify: 1) the role of magmatic accretion in propagation of nascent rifts adjacent to established ridges and consequent formation of transform faults or overlapping spreading centers; 2) mantle plume-induced ridge jumps in oceanic lithosphere; and 3) micro-continent formation by jumps into continental lithosphere. These objectives will be addressed with 3D numerical simulations and innovative laboratory experiments using colloidal fluids. To establish testable predictions from these models and experiments, results will be used to derive functional relationships between length- and time-scales of ridge jumps and observable quantities such as spreading rate, ridge migration rate, seafloor age, and melt flux. These relationships will be evaluated through comparison to a new database of jump statistics including jump distance, final segment length, transform fault or overlapping spreading center formation rate and location, and the time between repeat jumps.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.