A new approach in analogue modelling for studying kinematic complexities of transpression using the „MultiBox“


Seminar by Oliver Eisermann

Scaled analogue modelling has advanced to an effective experimental technique to better understanding complex geodynamic processes and to test respective hypotheses. Modelling transpression, simultaneous strike-slip and transverse shortening by means of analogue experiments continues to be a challenge in experimental tectonics. Here, we introduce our newly developed “MultiBox” tailored to model transpression and transtension. The computer controlled MultiBox consists of two halves, each of which contains a piston, whereby one halve is mobile and moves relative to a fixed halve parallel to the box midline. Using two-layer models scaled to length, deformation rate and viscosity, our experiments pertain to crustal-scale transpression as observed, in the Patagonian Andes. A base layer of silicone represents the viscous lower crust and distributes displacement. A 2:1 flour-sand mixture adheres to the brittle upper crust. Utilizing a state of the art 2D and 3D digital image correlation, individual increments of surface displacement and topography can be quantified with high accuracy. Moreover, a number of different derivatives of the measured vector field furnish new insights into the structural and morphological evolution of transpression zones. In particular, our results pertain to understand better upper crustal deformation of the Liquiñe-Ofqui-Fault-Zone, an alleged transpression zone in the Southern Volcanic Zone of the Andes.
Published Apr. 18, 2018 1:22 PM - Last modified Apr. 18, 2018 1:22 PM