Modeling episodic fluid‐release events in the ductile carbonates of the Glarus thrust

Research on the Swiss Tectonic Arena Sardona reveals that episodic fluid-release events, driven by carbonate decomposition and shear heating, are key to the movement of the Glarus thrust. This midcrustal deformation structure, characterized by tens of kilometers of displacement on an ultrathin layer (the principal slip zone), exhibits periodic stick-slip behavior due to overpressured fluids. The study demonstrates that slow ductile creep deformation raises temperatures through shear heating, triggering carbonate decomposition and the subsequent release of highly pressurized fluids. These fluids lubricate the principal slip zone, enabling significant movement along millimeter-thick bands. This model identifies carbonate decomposition as a critical process for thrust motion and explains the source of overpressured fluids accessing the slip zone.

Poulet, T., Veveakis, M., Herwegh, M., Buckingham, T., & Regenauer‐Lieb, K. (2014). Modeling episodic fluid‐release events in the ductile carbonates of the Glarus thrust. Geophysical Research Letters, 41(20), 7121–7128. Portico. https://doi.org/10.1002/2014gl061715