Publications
Tracing wedge-internal deformation by means of strontium isotope systematics of vein carbonates
Vein carbonates from the Swiss Tectonic Arena Sardona, part of the North Alpine fold-and-thrust belt, reveal critical insights into the tectonometamorphic evolution during continental collision. The study demonstrates that strontium isotope ratios (87Sr/86Sr) in these vein carbonates shift from an initial seawater-like signature to match the host rock's composition as metamorphic grade increases. This isotopic progression reflects the progressive equilibration of pore fluids with the host rock, providing a novel method to constrain deformation events such as bedding-parallel shearing, imbricate thrusting, folding, cleavage development, and mélange formation under diagenetic to low-grade metamorphic conditions. The findings enhance understanding of the prograde to early retrograde tectonic evolution in accretionary wedges.
Earthquakes in Switzerland and surrounding regions during 2017 and 2018
A system of sub-parallel strike-slip faults, likely within the uppermost crystalline basement of the eastern Aar Massif, was identified through analysis of the 2017 M L 4.6 Urnerboden earthquake and its aftershocks in Switzerland's Swiss Tectonic Arena Sardona region. The study, published in the Swiss Journal of Geosciences, detected and located 1227 earthquakes in 2017 and 955 in 2018, with the Urnerboden event being the strongest since the M L 5.0 Vaz earthquake of 1991. Focal mechanisms and hypocentre relocations revealed a NNW–SSE striking sinistral strike-slip fault system. Additionally, the research highlighted NE–SW oriented extensional to transtensional deformation along the Alpine Front between Lake Geneva and the Fribourg Fault, as well as rare shallow thrust faulting in the Jura fold-and-thrust belt, indicating contraction in Switzerland's northwestern Alpine foreland.
Control of 3-D tectonic inheritance on fold-and-thrust belts: insights from 3-D numerical models and application to the Helvetic nappe system
Three-dimensional tectonic inheritance plays a fundamental role in the evolution of fold-and-thrust belts, significantly influencing nappe formation and deformation patterns. This study demonstrates that initial basement horst and graben structures, along with laterally variable sedimentary layer strengths, control the detachment, folding, and horizontal transport of sedimentary units. Deeper half-grabens generate thicker nappes and more intense deformation in adjacent horsts, while shallower ones produce thinner nappes and less deformation. Mechanically weaker basements favor fold nappes, whereas stronger basements promote thrust sheets. The research applies 3-D thermo-mechanical numerical simulations to the Helvetic nappe system of the Central Alps, reproducing key features such as the closure of half-grabens, overthrusting, and nappe stacking, aligning with observed finite strain patterns, temperature distributions, and timing data. Strain localization and nappe transport are driven by initial geometrical and mechanical heterogeneities, highlighting the critical importance of tectonic inheritance in fold-and-thrust belt dynamics.
3D structural model and kinematic interpretation of the Panixer Pass Transverse Zone (Infrahelvetic Complex, eastern Switzerland)
A groundbreaking 3D structural model of the Panixer Pass Transverse Zone in eastern Switzerland reveals that the SSE-trending Crena-Martin Fold, a key feature of the Infrahelvetic Complex, was formed by multiple lateral ramps and fault-bend folds during an early thrust-dominated deformation phase (Cavistrau Phase). Contrary to previous hypotheses, this study demonstrates that ENE-WSW-directed shortening did not play a role in its formation. The model also shows that the final geometry of the zone resulted from a low-angle dextral strike-slip fault cutting across it. Field data indicates continuous NNW-directed shearing and transport, except for an early phase of north-directed shearing linked to foliation development in the Helvetic Nappes. This kinematic block model integrates seamlessly with established deformation sequences, providing a comprehensive understanding of the region's complex tectonic evolution.
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.
The Glarus Double Fold: a serious scientific advance in mid nineteenth century Alpine Geology
The Glarus Double Fold, once dismissed as a flawed tectonic model, is re-evaluated here as a significant scientific advance in mid-19th century Alpine geology. This study challenges the traditional view that Arnold Escher and Albert Heim's recumbent fold concept hindered progress by demonstrating its role as an early application of global contraction theory to the Alps. By contextualizing Swiss Alpine geology between 1800 and 1850, the research shows how the Double Fold model marked a paradigm shift from earlier vertical uplift theories—rooted in metamorphic processes—to large-scale horizontal displacements. This reinterpretation positions the Double Fold as a precursor to the nappe tectonic revolution, highlighting its importance in shaping modern understanding of Alpine orogeny.
Multiscale coupling and multiphysics approaches in earth sciences: Applications
Research reveals that the Glarus thrust, a seminal geological structure in the Swiss Alps, represents a complex interplay of thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes (THMC coupling). This km-scale rock package, pushed 40 km over its footwall as a solid body, exhibits a m-wide ductile shear zone with an ultralocalized central slip zone experiencing periodic extreme deformation akin to stick-slip events. The study demonstrates that such large-scale geological features emerge from non-conservative thermodynamic forces and can be characterized by the modified Gruntfest number (Gr), which measures dissipative processes reaching quasi-steady states. These findings highlight the importance of considering time and microstructure in THMC feedback simulations, providing a multiscale theoretical framework to understand earth's instabilities, including faults, folds, and convective patterns.
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