shear zones; rock deformation; polymineralic microfabrics; quartz; olivine; mylonites; polymineralic; ebsd
Herwegh Marco, Mercolli Ivan, Linckens Jolien, Müntener Othmar (2016), Mechanical anisotropy control on strain localization in upper mantle shear zones, in Tectonics
, 35, 1177-1204.
Linckens Jolien, Herwegh Marco, Müntener Othmar (2015), Small quantity but large effect — How minor phases control strain localization in upper mantle shear zones, in Tectonophysics
, 643, 26-43.
Haertel Mike, Herwegh Marco (2014), Microfabric memory of vein quartz for strain localization in detachment faults: A case study on the Simplon fault zone, in Journal of Structural Geology
, 68, 16-32.
Haertel Mike, Herwegh Marco, Pettke Thomas (2013), Titanium-in-quartz thermometry on synkinematic quartz veins in a retrograde crustal-scale normal fault zone, in Tectonophysics
, 608, 468-481.
Linckens J, Herwegh M, Muntener O, Mercolli I (2011), Evolution of a polymineralic mantle shear zone and the role of second phases in the localization of deformation, in JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
, 116, 1728-1750.
Linckens J, Herwegh M, Muntener O (2011), Linking temperature estimates and microstructures in deformed polymineralic mantle rocks, in GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
, 12(8), 1-19.
Herwegh Marco, Linckens J., Ebert A., Berger A., Brodhag S.H. (2011), The role of second phases for controlling microstructural evolution in polymineralic rocks: A review, in Journal of Structural Geology
, 33, 1728-1750.
Herwegh Marco, Poulet Thomas, Karrech Ali, Regenauer-Lieb Klaus, From transient to steady state deformation and grain size: A thermodynamic approach using elasto-visco-plastic numerical modeling, in Journal of Geophysical Research
With this proposal we ask for a three years prolongation of the currently running SNF project 'the role of polymineralic rocks in the evolution of shear zones' (200021-113563). Deformation in the earth's crust and upper mantle is strongly localized in, rheologically weak, large-scale shear zones, which act as important geodynamic anisotropies in extensional and compressional tectonic regimes. In order to better understand the strain localization behavior in the associated polymineralic fault rocks as a function of variable physico-chemical conditions, we investigate different natural large-scale crustal (Part A: olivine-rich) and mantle (Part B: quartz-rich) shear zones in combination with numerical modeling (Part C). Based on quantitative microstructural analyses (SEM, EBSD, CIP, EMPA), the effect of variations in the mineral content on the deformation of a dominant matrix phase is studied in terms of deformation mechanisms and rheology, as well as their changes in space and time. As an important new innovation, we are capable to transfer recently developed concepts for the mathematical description of microfabric evolution in polymineralic calcite mylonites to the olivine- and quartz-rich systems. Based on the link between micro-, meso- and large-scale structures, inferences on the evolution of the strain localization behavior will be obtained. In combination with geophysical parameters (rheology, seismic anisotropies etc.) the new data will allow improved predictions on the distribution of deformation at depths, which is of great interest in different disciplines of earth sciences such as structural geology, tectonics, petrology, rock mechanics, geophysics and geodynamics.The project benefits from national (ETHZ, Uni Lausanne, Uni Basel) and international collaborations with leading scientists from Australia, Germany and the US.