Strain partitioning in front of an obliquely convergent indenter

Abstract

Abstract.A model is presented that combines the traditional approach to transpression with the thin viscous sheet approximation of the lithosphere, to study deformation in front of an obliquely colliding indenter. The model produces a zone dominated by lateral simple shear (orogen parallel transcurrent movements) close to the indenter and a zone of dominant pure shear (orogen perpendicular pure shear/thrusting regions) further away from the indenting boundary. The relative width of simple shear dominated zone with respect to the more distant pure shear domain in terms of the angle of convergence is discussed. The possibility of development of transcurrent faults in front of an indenting plate is enhanced by the reactivation of fabric anisotropy created progressively during indentation.

Crustal influx, indentation, ductile thinning and gravity redistribution in a continental wedge: Building a Moldanubian mantled gneiss dome with underthrust Saxothuringian material (European Variscan belt)

“…The variable intensity of the D2 deformation and associated metamorphism can be interpreted in terms of a progressive indentation of the OSD from the east by a continental promontory (Figure 13c). The resulting strain distribution in front of an oblique indenter was successfully modeled by Ježek et al [2002] and Lexa et al [2003], though this model generates a finite strain pattern without folding. Alternatively, Bott and Dean [1973] and Blay et al [1977] proposed a model of progressive deformation and stress transfer across a visco‐elastic plate leading to progressive fold propagation away from the indenter as the early folds lock up and harden during progressive shortening.…”

Major shear zones of southern Brazil and Uruguay: escape tectonics in the eastern border of Rio de La plata and Paranapanema cratons during the Western Gondwana amalgamation

“…The most of the natural orogens accommodates transpressional deformation, with orogen-parallel tectonic transport in response to oblique convergence (Jezek et al 2002). In the transpressive shear zones (Harland 1971), the concept of strain partitioning is characterized into zones of simple shear deformation and domains of pure shear (Tikoff and Teyssier 1994).…”

Oroclinal buckling and associated lithospheric-scale material flow – insights from physical modelling: Implication for the Mongol-Hingan orocline

“…This is characteristic of a viscous deformation gradient typically developed in front of the moving piston (e.g. Houseman, 1986, 1989;Ježek et al, 2002). The EJTA crust-mantle interface (section 5) is irregularly deformed and shows upright cuspate folds further away from the piston.…”