[Paper Review] Carbon mineralization in CO2-seawater-basalt systems: Reactive transport dynamics and vesicular pore architecture controls

Mohammad Nooraiepour, Mohammad Masoudi+1 more|arXiv (Cornell University)|Jan 2, 2026

CO2 Sequestration and Geologic Interactions1 citations

TL;DR

The study uses flow-through experiments with CO2-acidified seawater and basaltic glass to show mineralization is nucleation-controlled and stochastic, influenced by residence time and vesicular pore architecture, with seawater reducing efficiency compared to freshwater.

ABSTRACT

Carbon mineralization in basaltic rocks may offer rapid, permanent \ce{CO2} storage, yet fundamental controls on reactive transport and precipitation patterns remain poorly understood. This study integrates flow-through experiments at 80\degree C using \ce{CO2}-acidified seawater with geochemical simulation and multi-scale pore imaging to elucidate mineralization dynamics in basaltic glass. Results reveal that carbonate precipitation is nucleation-controlled and stochastic rather than growth-controlled and deterministic, with isolated accumulations forming randomly despite continuous supersaturation. Residence time exerts primary control: reducing flow rate from 0.05 to 0.005\,mL/min proved necessary for visible precipitation. Post-experiment analyses identified calcium carbonate and smectite phases. Multi-scale characterization of three basalt facies revealed that connected porosity fractions (1.3--32\%) differ significantly from total porosity (18--42\%), demonstrating that network topology controls permeability. Micro-CT analysis revealed that pore coordination numbers in basalts (modal = 2) were notably lower than those in reservoir sandstones, creating serial flow paths that are vulnerable to catastrophic permeability loss from modest precipitation. Precipitation-induced clogging scenarios were proposed, where distributed small precipitates cause more severe permeability degradation than large accumulations. The use of seawater complicates geochemistry and reduces mineralization efficiency compared to freshwater. Findings emphasize the need for probabilistic reactive transport modeling frameworks and realistic pore topologies, which are fundamentally different from conventional CCS operations.

Motivation & Objective

• Clarify how residence time (advection) affects carbonate mineralization in basaltic rocks under CO2-charged seawater.
• Assess how vesicular basalt pore architecture controls reactive transport and mineral precipitation patterns.
• Identify mineralogical phases formed during CO2 mineralization in basalt under seawater conditions.
• Evaluate implications for probabilistic reactive transport modeling of basalt-hosted CO2 storage.

Proposed method

• Flow-through column reactor experiments at 80 °C with CO2-acidified seawater using two flow rates (0.05 and 0.005 mL/min).
• Crushed calcium carbonate and basaltic glass form two-zone reactor to study Ca2+ availability and basalt dissolution.
• Geochemical modeling with PHREEQC v3 using CarbFix database to simulate advection, dissolution, and mineral precipitation.
• Multi-scale pore imaging (micro-CT) and pore network modeling to characterize vesicular porosity and connectivity.
• Post-experiment XRD, XRF, SEM-EDS to identify minerals and spatial distribution of precipitates.

Experimental results

Research questions

• RQ1 How does fluid residence time influence carbonate mineralization kinetics and spatial patterns in CO2-charged seawater interacting with basaltic glass?
• RQ2 What role do vesicular and connected pore architectures play in reactive transport and mineral precipitation in basalts?
• RQ3 What carbonate and secondary minerals form under these conditions and how do they relate to saturation states and pH evolution?
• RQ4 How do nucleation vs growth control govern mineralization efficiency in basalt-seawater systems?
• RQ5 How does seawater (vs freshwater) impact mineralization efficiency and reaction pathways?

Key findings

• Visible carbonate precipitation requires lower flow rate (0.005 mL/min) and longer residence time; at 0.05 mL/min no macroscopic precipitation is observed.
• Precipitation is nucleation-controlled and stochastic, with isolated carbonate accumulations forming along the column rather than uniform growth.
• Calcite is the dominant precipitate; other supersaturated carbonates include dolomite, magnesite, and huntite, while nesquehonite remains undersaturated.
• Connected porosity (1.3–32%) differs from total porosity (18–42%), indicating network topology governs permeability and flow paths.
• Pore-scale analysis shows precipitation concentrates in peripheral boundary regions and within vesicular/cavitary features, causing potential clogging and permeability degradation.
• Seawater complicates geochemistry and lowers mineralization efficiency compared to freshwater; a probabilistic reactive transport framework is needed.