Thrusting versus folding: Laboratory modeling of compressional tectonics in the layered crust

Thrust faults are the main structures that accommodate compressional tectonics in accretionary wedges. In fold-and-thrust belts made of sedimentary formations, field studies show that significant folding accommodates the tectonic shortening.

However, most models of accretionary wedges account for homogeneous wedge, and the main structures accommodating shortening are thrust faults. The discrepancy between prominent folding in natural layered fold-and-thrust belts and dominant thrusting in homogeneous models lead to the following working hypothesis: a mechanical layering of sedimentary strata controls to a great extent the folding observed in fold-and-thrust belts.

The aim of this MSc project is to explore the effect of layering on the development of fold-and-thrust belts. The project will be based on a 2-dimensional laboratory apparatus that simulates compressional tectonics. The deforming crust is modelled with Mohr-Coulomb granular materials.

In Oslo, we have developed the unique expertise to prepare layered experiments, each layer is made of granular materials of contrasting cohesion and angle of friction. It is thus possible to prepare layered experiments with controlled layer thickness and cohesion/friction contrasts between the layers.

The development of the fold-and-thrust belts will be monitored from the side of the models, and quantitatively analyzed using Digital Image Correlation algorithm.

The project will be organized according to the following steps:

  • Design of laboratory apparatus
  • Running a selected series of experiments and data acquisition
  • Data analysis using in-house image analysis tools
  • The physical interpretation of the models
  • Comparison and integration with field examples

The learning outcomes of the project are the following:

  • Modelling design
  • Modelling strategy and parameter study
  • Quantitative data and physical analysis
  • Physics of brittle rock deformation and failure, which is applicable to other geological systems (basin structures, geomechanics)
  • Multi-disciplinary teamwork between groups of the Department of Geosciences

To implement this project, it is recommended to have:

  • Basic knowledge in programming skills, in order to analyze the laboratory data
  • Basic knowledge in brittle rock mechanics

The skills to be acquired during this MSc projects are highly relevant both for academic, geotechnical and consulting careers.

Published Oct. 23, 2020 4:29 PM - Last modified Oct. 23, 2020 4:29 PM