Collaborative Research: Testing Models of Calcite Microcrystal Diagenesis Through Experiments, Geochemistry, and Advanced Imaging

地下地质储集层中包含的资源是社区、公司和国家经济活动和活力的关键。要以经济高效的方式开发这些资源，至关重要的是了解这些储集层的管道--特别是岩石中的孔隙(空地)有多大，它们的连通性有多好，以及它们容纳了什么类型的流体。这项研究的重点是被称为微孔的小孔，以了解它们是如何形成的，以及它们在埋藏在地球中时是如何变化的。这一知识将使农民、自来水厂经理和石油和天然气行业等人能够少打井，增加他们的经济竞争力，减少对环境和人民的干扰。微孔也是用破碎的石灰岩建造的道路过早恶化的原因。因此，这项工作的结果可能会导致更坚固的高速公路，降低建设和维护成本，同时为司机提供更安全、更顺畅的驾驶。前人的工作表明，大多数微孔都寄生在方解石微晶的骨架中。目前的研究旨在了解石灰岩中这些微晶结构的基本控制因素。方解石微晶的形成和演化已经提出了许多概括性的途径。然而，没有人以一种强有力的方式将微晶结构与成岩过程联系在一起。我们的目标是将实验室实验、先进的成像和高分辨率的地球化学技术相结合，以更好地了解方解石微晶的成岩作用，从而了解它们之间的微孔。具体地说，我们建议使用实验和各种自然样品来评估各种方解石微晶结构的地球化学不均一性和成因演化。我们假设微晶化学的空间差异将揭示不同的微晶结构与成岩轨迹上胶结作用增加的位置相关(即微晶结构变得更适合渐进埋藏和胶结作用)。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The resources contained in underground geologic reservoirs are key to the economic activity and vitality of communities, companies, and countries. To develop these resources in a cost-effective manner, it is vital to understand the plumbing of these reservoirs-specifically how big the pores (open spaces) are in the rocks, how well they are connected, and what kind of fluids they hold. This study focuses on small pores, called micropores, to understand how they form, and how they change as they are buried in the Earth. This knowledge will allow people such as farmers, water plant managers, and the oil and gas industry to drill fewer wells, increasing their economic competitiveness and decreasing disturbances to the environment and people. Micropores are also responsible for premature deterioration of roads constructed with crushed limestone. Therefore, the results from this work could lead to more robust highways, reducing construction and maintenance costs, while providing a safer and smoother ride for drivers. Previous work shows that most micropores are hosted in a framework of calcite microcrystals. The current research aims to understand the fundamental controls on the textures of these microcrystals in limestones. Numerous generalized pathways for calcite microcrystal formation and evolution have been proposed. None, however, has tied microcrystal texture to diagenetic process in a robust manner. Our aim is to integrate laboratory experiments, advanced imaging, and high-resolution geochemical techniques to better understand the diagenesis of calcite microcrystals and thus the micropores between them. Specifically, we propose to use experiments and a wide variety of natural samples to assess the geochemical heterogeneity and genetic evolution of the various calcite microcrystal textures. We hypothesize that spatial variations in microcrystal chemistry will reveal that the different microcrystal textures correlate to positions along a diagenetic trajectory of increasing cementation (i.e., microcrystal textures become more fitted with progressive burial and cementation).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.