Two-Phase Damage and the Interactions between Earth's Mantle and Climate: From Plate Tectonic Feedbacks to Carbon Capture

地幔和气候系统之间的相互作用是通过复杂的过程和不同的时间尺度发生的。在地质时间尺度上，构造旋回通过造山和风化作用缓冲二氧化碳，为地球提供了温带气候。然而，板块构造运动并非不受气候条件的影响。虽然液态水被认为是润滑板块构造的必要条件，但最近的理论认为，较冷的表面会促进岩石圈的破裂或破坏，这就导致了类似板块的地幔在地球上流动，而不是在金星上。在人类的时间尺度上，燃烧化石燃料产生的碳的快速外流可能最好的缓解办法是将二氧化碳有效地送回地幔，即在基性和超基性岩石中封存碳。这种地幔-气候相互作用的过程，无论是自然的还是人为的，都涉及到化学反应、粒度演化和损伤力学等附加复杂性的多相物理。这一建议是为了PI正在进行的两相损伤理论的发展和应用工作；在此，我们建议解决两个问题：1。板块构造如何开始和板块边界如何演化仍然是地球动力学中未解决的问题，并提供了超越模拟当今瞬时板块运动的板块生成理论的测试。此外，这样的板块生成问题可能与气候演化有关。如果板块的产生和类似地球的温带气候是相互需要的，那么可能存在一个临界表面温度，在这个温度下，行星会或不会达到凉爽/类似板块的状态，即在地球和金星之间的某个地方；这对太阳系内外的类地行星演化都有影响。地球早期板块形成的时间和活力也会影响太古宙的气候，对气候的估计变化很大。新板块边界的形成和板块演化（收缩和重组）也与气候变化有关（例如，CO2通量平衡的变化、大陆构造对海洋环流的影响、风化作用、冰形成等）。2. 损伤增强的渗流如何促进地幔源岩的碳固存？特别是，在基性环境中注入二氧化碳溶液时，如何通过传播损伤锋来产生碳酸盐反应的新矿物表面？例如，在这些环境中，压力脉冲或孔隙度波会同时产生空隙和降低颗粒尺寸，从而增强二氧化碳的反应性。这些主题涵盖了地幔-气候相互作用的末元时间尺度。然而，自然的长期过程可以告诉我们如何缓解短期失衡。在不把问题推给子孙后代的情况下，减少人为的二氧化碳增加需要一个地质学上的长期解决方案，最好的解决办法是通过模拟地幔矿物风化的自然碳缓冲。这个提议将把长期的、行星尺度的观点与处理地球地幔气候系统的有用方法结合起来。该项目由地球物理计划和网络基础设施办公室的ci重用风险基金支持。

The interaction between the Earth's mantle and climate systems occurs through complex processes and over disparate time scales. On the geological time scale, the tectonic cycle buffers CO2 through mountain building and weathering, providing Earth with a temperate climate. The operation of plate tectonics, however, is not impervious to climatic conditions. Although liquid water is thought necessary to lubricate plate tectonics, recent theories postulate that a cool surface promotes lithospheric failure or damage, which then permits plate-like mantle flow on Earth, but not Venus. On human time scales, the rapid efflux of carbon from burning fossil fuels is possibly best mitigated by effectively returning CO2 to the mantle, i.e., by carbon sequestration in mafic and ultramafic rocks. Such processes of mantle-climate interaction, whether natural or man-made, involve multi-phase physics with the additional complexities of chemical reactions, grainsize evolution, and damage mechanics. This proposal is for the PI's on-going work on the development and application of two-phase damage theory; here we propose to address two issues:1. How plate tectonics initiated and plate-boundaries evolve remain unsolved questions in geodynamics, and provide tests of plate generation theories that go beyond modeling instantaneous present-day plate motions. Moreover, such plate-generation questions are possibly linked to climate evolution. If plate generation and a temperate Earth-like climate are mutually required of each other, then there is probably a critical surface temperature at which a planet does or does not achieve a cool/plate-like state, i.e., somewhere between Earth and Venus; this has implications for terrestrial planet evolution both within and outside our own solar system. The timing and vigor of plate initiation on early Earth would also have influenced Archaean climate, estimates of which are highly variable. The formation of new plate boundaries and plate evolution (shrinkage and reorganization) is also associated with climate variation (e.g., by changes in CO2 flux balance, the effect of continental configurations on ocean circulation, weathering, ice-formation, etc.). 2. How can damage enhanced percolation facilitate carbon sequestration in mantle derived rocks? In particular, how are fresh mineral surfaces for carbonate reactions generated by propagating damage fronts during injection of solutions of CO2 in mafic settings? For example, pulses of pressure or porosity waves in these settings would be associated with both void-generating and grainsize-reducing damage that would then enhance CO2 reactivity. These topics bracket the end-member time-scales in mantle-climate interactions. However, the natural long term processes can inform us how to mitigate short-term imbalances. Mitigating anthropogenic CO2 increases without pushing the problem to future generations requires a geologically long-term solution, and is best addressed by mimicking natural carbon buffering by weathering of mantle minerals. This proposal will combine long-term, planetary-scale perspectives with useful approaches to treating the Earth's mantle-climate system.This project is supported by the Geophysics Program and the Office of Cyberinfrastructure's CI-Reuse Venture Fund.