The Formation and Stabilization of Thickened Lithosphere

大陆只占地球表面的30%，是人类居住的唯一场所，但不幸的是，这些大陆也是广泛分布的变形区域，导致地震，火山活动，山体滑坡等，最终，这些破坏性的过程是地球失去热量的结果，这些热量是在其内部储存的（通过放射性物质的衰变）。 这种能量如何转化为塑造大陆表面的过程仍然是一个突出的挑战，对于理解是什么使一些地区在构造上“安全”而不是潜在的危险具有重要意义。幸运的是，地球通过被称为“板块”的大陆内部区域提供了对其构造演化的独特见解。 巨子是一个厚（约200- 300公里）、古老（约30 - 40亿年）的区域，自其起源以来就避免了变形。 这意味着在地球历史的大部分时间里，当地球表面的其他部分被构造过程改变时，地球上的小行星抵抗被分裂，破碎，压缩或重新熔化。 这种长寿和生存能力的彗星提供了理解背后的驱动力变形在地球的历史。本研究的目的是通过绘制厚的、稳定的大陆岩石圈形成的时间、方式和原因，以及评估地球当前构造稳定区域未来的生存能力和寿命，来增加我们对这一问题的理解。本项目将理论定标与二维和三维随时间变化的数值模型相结合，以定量地确定岩石圈稳定和稳定所需的动力学条件。它将考虑两个不同的候选人，使增厚的大洋岩石圈和岛弧物质的浮力海洋岩石圈。它还将探讨二次过程的作用，在此过程中，致密层（如榴辉岩或镁铁质堆晶岩）的去除有助于促进岩石圈的稳定性。它将比较模拟中产生的流变学和成分结构与深超声波岩石圈内部的地震观测。最后，它将解决的大小，频率和性质的滴可能产生的基础上的岩石圈的超声波。通过关注大陆演化的一个关键阶段，这项工作将为早期地球动力学提供新的约束，在此期间形成了大陆岩石圈的核心。

Continents, covering only ~30% of the Earth's surface, are the sole location of human habitation, yet, unfortunately are also regions of widely distributed deformation resulting in earthquakes, volcanism, landslides, etc. Ultimately, these destructive processes are the consequence of the Earth losing heat that is stored & generated (via decay of radioactive material) within its interior. How this energy translates into the processes that shape the continent's surface still remains an outstanding challenge with great significance for understanding what makes some regions tectonically "safe" versus potentially dangerous. Fortunately, the Earth provides unique insight into its tectonic evolution via areas of the continental interior called cratons. Cratons are thick (~200-300km), old (~3-4 billions of years) regions that have avoided deformation since their origin. Meaning that for the majority of Earth's history while the rest of the Earth's surface was being modified by tectonic processes, cratons resisted being split apart, broken up, compressed or remelted. This longevity and survivability of cratons provides understanding of the driving forces behind deformation over Earth's history. This study aims to increase our understanding of this problem by focusing on mapping out when, how and why thick, stable continental lithosphere forms as well as assessing the future survivability and longevity for current tectonically stable regions of the Earth.This project combines theoretical scalings with two- and three-dimensional time-dependent numerical models to quantitatively determine the dynamic conditions required to thicken and stabilize lithosphere. It will consider two different candidates to make thickened cratonic lithosphere from - buoyant oceanic lithosphere and island arc material. It will also explore the role of a secondary process whereupon the removal of a dense layer (such as eclogite or mafic cumulates) helps promote the stability of cratonic lithosphere. It will compare the generated rheological and composition structure within simulations against seismic observations of the interior of deep cratonic lithosphere. Finally, It will address the size, frequency and nature of drips potentially arising from the base of cratonic lithosphere. By focusing on a critical stage in continental evolution, this work will provide new constraints into the dynamics of the early Earth during which the cores of continental lithosphere were formed.