Finding the fingerprint of mantle dynamics on plate tectonic processes

板块构造活动主要是由地壳（“自上而下”）还是地幔（“自下而上”）过程驱动的，这是地球动力学中一个持久的挑战。我的研究项目是利用高性能计算来研究板块构造过程，以识别这种机制中地幔的潜在指纹。对于这个资助周期，我将重点关注四个相互关联的领域，以实现这一长期目标。北极是一个反复出现大陆分裂事件的地区，但对这一过程的理解有限。其目标是根据基本原理建立北冰洋构造演化的详细数值模型。这些模型将结合几十年的区域地质制图所创造的知识，并将建立在我在识别大陆分裂（裂谷）事件中自上而下或自下而上过程指纹的研究专长之上。正如在北极地区看到的那样，反复的裂谷事件通常会产生“地体”，这是地球大陆的小碎片，从它们的主要领域分离出来。尽管全球普遍存在，但这些碎片产生的过程并没有得到很好的理解，以前的工作主要集中在它们的来源上，而不是它们的起源。这里的工作旨在推断地形创建中自上而下和自下而上过程的相对重要性。在全球范围内，北冰洋的演化也跨越了罗迪尼亚超大陆的最终分裂和盘古大陆的合并和分裂。考虑到较长的时间框架，深入了解地幔对流与超大陆旋回之间的关系对于理解地幔过程在北冰洋演化中的作用至关重要。通过三维数值模拟，我们将研究对对流地幔自下而上动力学产生影响所需的超大陆的大小。在过去的50年里，加拿大东部、美国、非洲和欧亚大陆都发生过深度（大约30公里）的板块内地震。这些深地震对浅层构造的潜在影响很少被研究。现代数据科学技术非常适合于评估地壳对板内深地震的反应。通过建立历史事件对地壳构造自下而上影响的潜在指纹，研究项目可以将这个可测试的框架应用于未来的事件。这个多尺度程序的新颖之处包括使用最先进的计算模型来为可用数据添加第四个维度（时间）。通过模拟区域构造（例如，北极动力学和深部地震）和全球尺度特征（例如，超大陆和地体），拟议的研究将致力于了解哪些板块过程是由地幔（自下而上）或地壳（自上而下）发起的长期目标。

Whether plate tectonic activity is primarily driven by crustal (`top--down') or mantle (`bottom--up') processes is an enduring challenge in geodynamics. My research program investigates plate tectonic processes using high performance computing to identify the potential fingerprint of the mantle in such mechanisms. For this grant cycle, I'll focus on four interlinked areas that work towards this long term goal.  The Arctic is a region where repeated episodes of continental breakup have been documented but an understanding of the processes is limited. A goal will be to produce detailed numerical models of the tectonic evolution of the Arctic Ocean from first principles. The models will incorporate knowledge created by decades of regional geological mapping and will build on my research expertise in identifying the fingerprint of top-down or bottom-up processes in episodes of continental breakup (rifting). Repeated episodes of rifting as seen in the Arctic region commonly produce `terranes', which are small fragments of the Earth's continents that become isolated from their principal domain. Despite global ubiquity, the processes involved in the generation of such fragments are not well understood, with previous work mainly focusing on their provenance rather than how they originated. The work here aims to deduce the relative importance of top--down and bottom--up processes in the creation of terranes. On a global scale, the evolution of the Arctic Ocean also spans the final breakup of supercontinent Rodinia and the amalgamation and breakup of Pangea. Given the long timeframe, a deeper understanding of the relationship between mantle convection and the supercontinent cycle is critical in understanding the role of mantle processes in the evolution of the Arctic Ocean. Through 3D numerical modelling, we will investigate the size of a supercontinent required to produce an impact on bottom--up dynamics from the convective mantle. Moving closer the present-day, instances of deep (>30 km) intraplate earthquakes have occurred over the past 50 years in Eastern Canada, the United States, Africa, and Eurasia. The potential impact of these deep earthquakes on shallower tectonics is rarely investigated. Modern data science techniques are well suited to evaluate the response of the crust to intraplate deep earthquakes. By building a potential fingerprint of a bottom--up impact on crustal tectonics from historical events, the research program can apply this testable framework to future events. The novelty of this multi-scale program includes the use of state--of--the--art computational models to add a fourth dimension (time) to available data. By modelling regional tectonics (e.g., Arctic dynamics and deep earthquakes) and global--scale features (e.g., supercontinents and terranes), the proposed research will work towards the long--term goal of understanding which plate processes are initiated from the mantle (bottom-up) or the crust (top-down).