Simulations of crack initiation in a quartz grain.
Molecular dynamics simulations of crack initiation in a quartz grain (Si–light green, O–dark green atoms) into a carbon dioxide environment (C–black, O–red atoms). The presence of carbon dioxide molecules leads to void formation in the fracture tip process zone, and crack propagation occurs at lower applied strain compared to dry quartz. Credit: Simeski and Ihme [2023], Figure 7
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Solid Earth

Molecular dynamics rely on empirical atomic potentials to reproduce the nanoscale behavior of natural and engineered systems. In a new study, Simeski and Ihme [2023] use reactive molecular dynamics to simulate an important geological process: the onset of fracturing of quartz in the presence of fluids.

The authors use atomic potentials of quartz (a major constituent of the Earth’s upper crust), carbon dioxide and water. These potentials are now well-established, allowing to simulate the dynamics of systems that contain hundreds of thousands of atoms over several tens of nanoseconds. They used the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) software to reproduce the onset of fracturing of quartz in the presence of carbon dioxide and water. An important outcome is that quartz may break under a lower stress at the nanoscale in presence of carbon dioxide or water than when dry. This result may be considered when operating geological reservoirs where carbon dioxide is planned to be stored.

Citation: Simeski, F., & Ihme, M. (2023). Corrosive influence of carbon dioxide on crack initiation in quartz: Comparison with liquid water and vacuum environments. Journal of Geophysical Research: Solid Earth, 128, e2022JB025624.

—François Renard, Associate Editor, JGR: Solid Earth

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