Multi-scale rheology and strain localization of the continental lithosphere

• Applicant: Dr. Christoph Schrank
• Subject Area: Palaeontology
• Term: from 2009 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 157155817

Mechanical flow properties (i.e., rock rheologies) control the deformation of rocks and are therefore of utmost importance for the general understanding of plate tectonics, mountain building, earthquakes, and structural mineral, oil, and gas deposits. However, little is known about rheology on dm- to 10km scales although these scales are of highest relevance for economic and environmental geology. This project intends to fill this gap with an innovative experimental approach that reconciles laboratory deformation experiments and geological field data with thermal-mechanical multi-scale numerical experiments. The fundamental uncertainty regarding rock rheology on intermediate scales exists because constraints for rheology mainly stem from mm- to cm-scale laboratory deformation experiments or from the inversion of large-scale geophysical and geodetic observations (10-100km scale). Both cannot be easily extrapolated to intermediate length scales because rheology is scale-dependent and highly dynamic over geological time and length scales. The physical complexity of this problem does not permit theoretical solutions. Therefore, an innovative numerical approach calibrated with laboratory and natural data is proposed that employs a new thermodynamically consistent multi-scaling method. Three main outcomes are expected from this project: 1) Flow laws of rock masses are obtained from dm- to km scale. 2) Quantitative laws describing how rock rheology evolves with scale are determined, connecting small-scale laboratory experiments with largescale geophysics and geodetics. 3) The physical scaling lengths governing shear localization on dm- to km scales under geological conditions are identified.

• DFG Programme: Research Fellowships
• International Connection: Australia
• Host: Professor Dr. Klaus Regenauer-Lieb