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

地下地质储层所含的资源是社区、公司和国家经济活动和活力的关键。为了以经济有效的方式开发这些资源，了解这些储层的管道是至关重要的，特别是岩石中的孔隙（开放空间）有多大，它们之间的连接程度如何，以及它们所含的流体类型。这项研究的重点是被称为微孔的小孔隙，以了解它们是如何形成的，以及当它们被埋在地球中时是如何变化的。这些知识将使农民、水厂管理人员以及石油和天然气行业的人们能够减少钻井数量，提高他们的经济竞争力，减少对环境和人类的干扰。微孔也是石灰石碎石路面过早老化的原因。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、更平稳的驾驶体验。先前的研究表明，大多数微孔都位于方解石微晶体的框架中。目前的研究旨在了解石灰岩中这些微晶体结构的基本控制因素。方解石微晶形成和演化的许多广义途径已被提出。然而，没有一种方法能将微晶结构与成岩过程联系起来。我们的目标是将实验室实验、先进成像和高分辨率地球化学技术结合起来，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。具体而言，我们建议利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非均质性和遗传演化。我们假设微晶化学的空间变化将揭示不同的微晶结构与胶结作用增加的成岩轨迹上的位置相关（即微晶结构更适合于逐渐埋藏和胶结作用）。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.