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.
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