Evolution of fault zones in layered sand-clay sequences

点击翻译按钮获取中文摘要

Faults are ubiquitous structures in the Earth’s upper crust. Understanding the evolution of their mechanical and transport properties is an important challenge in many areas of basic and applied geosciences. This interdisciplinary research project aims to understand the evolution of fault zones in layered sand-clay sequences in sedimentary basins, from the patterns of initial strain localization to the formation of a highly strained fault gouge. Building on our previous work, we will integrate three approaches: - Field observations of faults in layered sand-clay sequences to measure displacement gradients and characterize fault gouges together with mechanical properties (Lignite quarries in NRW, Airport Road outcrop, Miri, Sarawak, Malaysia), - Scaled physical models of strain localization in sand- clay layercakes in water-saturated experiments, using materials with accurately known properties, quantifying the displacement field with Particle Image Velocimetry, and - Numerical modelling, using Finite Element models with adaptive remeshing (ELFEN) to model the development of localization in our sandbox models and discrete element models to study the evolution of fault gouge. Finally, after validation by comparison of displacement fields and stresses in the numerical and physical models, the numerical models will be extrapolated to geologically relevant length scales and boundary conditions so that the results can be directly compared with field observations.