Geosciences Seminar Mon, 06/27/2016 - 10:14

"Deformation patterns and stress distribution within overriding plates during seamount subduction: Numerical modelling" by Jonas Ruh, SNSF Advanced PostDoc Fellow at ICTJA-CSIC, will be held at room Sala d'Actes of Institut de Ciencies del Mar (ICM - www.icm.csic.es).

Thin-skinned fold-and-thrust belts related to convergence tectonics develop by scraping off a rock sequence along a weaker basal d├ęcollement often formed by water-saturated shale layers or low-viscosity salt horizons. Numerical models with sophisticated rheologies are used to investigate the structural evolution of fold-and-thrust belts overlying different types of d├ęcollements. In addition, the effect of the strength of shear zones within such fold-and-thrust belts is investigated. Shear zones are usually weaker than surrounding rocks, but whether weakening depends on accumulated strain or strain rate is still a matter of debate. Aside rheological effect, geometrical constraints have a large influence on the structural evolution of fold-and-thrust belts. For example, seamounts entering active subduction zone trenches initially collide with the frontal sedimentary accretionary wedges resulting in severe deformation of the overriding plate. A typical feature of this deformation is the occurrence of submarine landslides due to gravitational instabilities. 3D numerical models are applied to infer deformation patterns and stress distribution