Deciphering the duration of fluid-rock interaction

地球结晶岩石圈的很大一部分正在(并且已经)被流体驱动的矿物反应进行化学修饰。这些反应驱动了几个相应的流体中介的岩石转化过程，包括那些控制山带稳定性、热液矿床的形成和人为二氧化碳的封存的过程，这些过程还可能导致巨大的影响，如板块界面的大地震。然而，尽管流体-岩石相互作用对于地壳和地球化学储集层的动态演化具有独特的意义，但这些相互作用的时间尺度基本上仍然不受限制。到目前为止，保留在岩石记录中的流体-岩石相互作用的持续时间已经根据计时模型进行了评估，到目前为止，我们和其他人认为这是正确确定这些持续时间的方法。然而，没有研究证实这一点：计时模拟的结果没有与实验研究的结果相比较，因为没有进行过这样的实验。因此，该项目的主要目标是开发实验，以测试计时模型是否能够可靠地确定流体-岩石相互作用的持续时间。我们提出的突破性研究在于应用一种高度创新的实验装置来识别和验证或在需要的地方修改输入参数和支持数值计时建模方法的假设。通过这样做，该项目还将导致更好地理解流体和岩石之间相互作用的关键过程，例如如何在反应的颗粒边界发生传输，孔隙度和渗透率的瞬时特性如何演变，以及颗粒边界介导的传输如何有助于多晶材料的有效整体反应性和可运输性。

Enormous portions of the Earth’s crystalline lithosphere are being (and have been) chemically modified by fluid-driven mineral reactions. These reactions drive several consequential fluid-mediated rock transformation processes, including those that govern the stability of mountain belts, the formation of hydrothermal mineral deposits and the sequestration of anthropogenic CO2, and these processes can also lead to dramatic effects such as megathrust earthquakes at plate interfaces. However, despite the unique significance of fluid-rock interactions for the dynamic evolution of the Earth’s crust and Earth’s chemical reservoirs, the timescales of these interactions remain essentially unconstrained. To date, the durations of fluid-rock interactions, as retained in the rock record, have been assessed according to chronometric modelling, which we and others have, so far, considered to correctly determine these durations. However, no studies have verified this: The results of chronometric modelling have not been compared to those of experimental studies, because no such experiments have been performed. Therefore, the main goal of this project is to develop experiments to test whether chronometric modelling can reliably determine the duration of fluid-rock interactions. Our proposed breakthrough research lies in applying a highly innovative experimental setup to identify and verify or, wherever needed, modify the input parameters and the assumptions underlying the numerical chronometric modelling approach. In doing so, the project will also lead to a better understanding of key processes underlying the interaction between fluid and rocks, such as how transport occurs at reactive grain boundaries, how the transient properties of porosity and permeability evolve and how grain boundary-mediated transport contributes to the effective bulk reactivity and transportability of polycrystalline materials.