Vision topic calcite dissolution

Calcite dissolution is often driven by carbonic acid in subsurface systems. This is of crucial importance for karstic systems, where CO₂ is the main driver of karstification, but it is also relevant in large-scale geological CO₂ sequestration in deep saline aquifers, where calcite-aggressive waters may dissolve rocks and thus create pathways. In karstic systems, there is, similar as in the vision topic ‘salt’ a strong coupling to the atmosphere since CO₂ concentrations in caves are typically influenced by atmospheric processes like precipitation, temperature variations, or barometric fluctuations. Another similarity to processes that are relevant also in the salt vision topic, is the occurrence of density-driven instabilities; in this particular case, this appears at the gas-water interface, where CO₂ dissolves from the gas phase into the water phase, leading to an increase of density at the interface and thus to an instable layering with convection enhanced dissolution as a result.

Research questions, we address, are the following:

1. How to predict dissolution rates in porous rock or fractured media dependent on flow regimes, transport time scales, or reaction kinetics, etc.?
2. How to identify the driving forces for CO2 replenishment in karstic systems beyond the established karstification theories, i.e. in particular in stagnant water bodies?

Several projects within SFB 1313 have dedicated work packages for the vision topic calcite dissolution. Additionally, associated researchers, closely related to the work of SFB 1313 but not financed by SFB 1313, complete the team working on the vision topic.

• Project A02
• Project B05
• Project C03
• Project CX6