Collaborative research: Microscopic fracturing and macroscopic weakening: A novel model for bedrock fracturing by biotite weathering

基岩是如何分解成土壤的？ 这个问题引起了广泛的兴趣，因为基岩断裂会影响滑坡灾害、全球碳循环以及土壤和河流的养分供应。 该项目的主要目标是了解单一类型的常见矿物-黑云母的风化作用如何随着风化作用而膨胀-驱动基岩断裂。 这将检验一个长期存在的假设，即基岩断裂主要是由黑云母风化驱动的。这项工作将通过数值模拟、现场观察和实验室测量相结合来解决这个问题。 该项目的核心是开发一种新颖而强大的基岩断裂数值模型。 它将被用来调查几个基本问题：如何发展的裂缝取决于黑云母的特点，如大小，方向和丰度？ 在什么条件下黑云母风化是基岩断裂的主要驱动力？ 为了测试模型预测，将在两个现场进行黑云母和断裂特征的新测量，其中一个现场被认为是黑云母风化主导岩石断裂（波多黎各的卢基略临界带观测站），以及黑云母风化作用预计不太重要的一个（南塞拉内华达州临界区天文台，加州）该奖项反映了NSF的法定使命，并通过使用基金会的智力价值进行评估，更广泛的影响审查标准。

How does bedrock break down into soil? This question is of wide interest because bedrock fracturing influences landslide hazards, the global carbon cycle, and the supply of nutrients to soils and streams. This project's main goal is to understand how the weathering of a single type of common mineral - biotite, which expands as it weathers - drives bedrock fracturing. This will test a longstanding hypothesis that bedrock fracturing is mainly driven by biotite weathering.This work will tackle this question through a combination of numerical modeling, field observations, and laboratory measurements. At the center of this project is the development of a novel and powerful numerical model for bedrock fracturing. It will be used to investigate several fundamental questions: How does the development of fractures depend on biotite characteristics like size, orientation, and abundance? Under what conditions is biotite weathering the dominant driver of bedrock fracturing? To test the model predictions, new measurements of biotite and fracture characteristics will be conducted at two field sites, one where biotite weathering is thought to dominate rock fracture (the Luquillo Critical Zone Observatory, Puerto Rico), and one where the effects of biotite weathering are expected to be less important (the Southern Sierra Nevada Critical Zone Observatory, California).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.