Weatherization and mineralization are natural processes by which rocks of certain chemical compositions react with carbon dioxide (CO2)Сeither from ambient air or from concentrated CO2 streams collected during industrial processesСand undergo reactions that lead to the CO2 binding to the rock. These processes thus represent a potential pathway for decarbonization, an opportunity to use natural processes to sequester large amounts of atmospheric carbon in mineralized form. This grant supports research by Christine McCarthy and Ah-Hyung Park that will investigate key questions about the basic physics and chemistry of rock weathering and mineralization, with an aim toward understanding how these processes can be enhanced and accelerated. For example, mineralization can result in an effect called Тreactive crackingУ in which pores or fissures in the rock open, creating more surface area that allows for additional mineralization. This generates a positive CO2 solidification feedback loop. Sometimes, however, mineralization does not result in reactive cracking. Instead, as a rock mineralizes, pores within the rock become clogged by carbonated minerals, leading the rock pores to become ТcloggedУ and hindering further mineralization. The team led by McCarthy and Park will study what factors lead to differences between these ТcrackingУ versus ТcloggingУ effects, and they will assess how these reactions might impact larger-scale efforts to mineralize CO2 in geologic systems. This study will include a series of laboratory experiments that will examine a range of different stress, temperature, and acidity conditions that might hinder or accelerate such cracking or clogging processes, with these lab-based results used to model how such findings might scale up in real-world field conditions.