Experimental data on scaled analogue experiments modelling GPS velocity field variations and kinematic partitioning in the Southern Andes (34°S to 42°S)

Abstract

The southern Andes are regarded as a typical subduction orogen formed by oblique plate convergence. Despite decades of studies, there is considerable uncertainty as to how deformation is kinematically partitioned in the upper plate. Using scaled analogue experiments modelling, we test the concept of dextral transpression for this orogen. We advocate that the GPS velocity field portrays interseismic deformation related to deformation of strong crust north, and weak crust south, of 37°S. Contrary to the popular hypotheses that the Liquiñe-Ofqui Fault Zone, a prominent intra-arc deformation zone, takes up most of the plate boundary-parallel dextral strike-slip, we find that dextral transpression affects the entire model orogen through tectonic segmentation of crust.

Moreover, prominent, regularly spaced sinistral oblique-slip thrust faults, interpreted as antithetic Riedel shears, developed spontaneously in all of our experiments and call into question the general believe that their NW-striking natural equivalents formed from pre-Andean discontinuities. Our experiments prompt us to reconsider the apparently well-established geodynamic concept that strain and margin-parallel displacement is localized on a few margin-parallel faults in the southern Andes.

Authors

• Eisermann, Jan Oliver;Universität Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany
• Göllner, Paul Leon;Universität Hamburg, Hamburg, Germany
• Riller, Ulrich;Universität Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany

Contact

• Riller, Ulrich (Researcher) ; Universität Hamburg, Hamburg, Germany; ➦

Contributors

Analogue modelling laboratory (University Hamburg, Germany)

Keywords

GPS velocity field, kinematic partitioning, Strain partitioning, Southern Andes, Transpression, oblique plate convergence, analogue experiment, modeling, Liquiñe-Ofqui Fault Zone, interseismic deformation, Multibox, EPOS, European Plate Observing System, multi-scale laboratories, analogue models of geologic processes, analog modelling results, Digital Image Correlation (DIC) / Particle Image Velocimetry (PIV) > StrainMaster (La Vision GmbH), fault > oblique slip fault, fault > strike-slip fault, normal fault, geologic process, tectonic process > orogenic process, Glass/Plexiglas box > Glass/Plexiglas box (meter scale), Sandbox > Sandbox (meter scale), Shear box, Squeeze box, Microspheres > Glassy, Sand > Corundum Sand, Sand > Quartz Sand, Silicon/Silly putty/PDMS, Surface image, tectonic and structural features, tectonic setting > back arc setting, tectonic setting > plate margin setting > active continental margin setting, tectonic setting > plate margin setting > volcanic arc setting, Time lapse camera, Digital Image Correlation (DIC) / Particle Image Velocimetry (PIV) > StrainMaster (La Vision GmbH), Glass/Plexiglas box > Glass/Plexiglas box (meter scale), Microspheres > Glassy, Sand > Corundum Sand, Sand > Quartz Sand, Sandbox > Sandbox (meter scale), Shear box, Silicon/Silly putty/PDMS, Squeeze box, Surface image, Time lapse camera, fault > oblique slip fault, fault > strike-slip fault, geologic process, normal fault, tectonic and structural features, tectonic process > orogenic process, tectonic setting > back arc setting, tectonic setting > plate margin setting > active continental margin setting, tectonic setting > plate margin setting > volcanic arc setting

GCMD Science Keywords

• EARTH SCIENCE > SOLID EARTH > GEODETICS
• EARTH SCIENCE > SOLID EARTH > TECTONICS > PLATE TECTONICS > STRAIN
• EARTH SCIENCE SERVICES > MODELS > GEOLOGIC/TECTONIC/PALEOCLIMATE MODELS