rheology; sheet silcate; liberation of fluids; flow pathes; porosity
Peters Max, Herwegh Marco, Paesold Martin K., Poulet Thomas, Regenauer-Lieb Klaus, Veveakis Manolis (2016), Boudinage and folding as an energy instability in ductile deformation, in JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
, 121(5), 3996-4013.
Peters Max, Berger Alfons, Herwegh Marco, Regenauer-Lieb Klaus (2016), Strain localization in ductile rocks: A comparison of natural and simulated pinch-and-swell structures, in TECTONOPHYSICS
, 680, 140-154.
Dielforder Armin, Berger Alfons, Herwegh Marco (2016), The accretion of foreland basin sediments during early stages of continental collision in the European Alps and similarities to accretionary wedge tectonics, in Tectonics
, 35, 1.
Peters Max, Veveakis Manolis, Veveakis Manolis, Poulet Thomas, Poulet Thomas, Karrech Ali, Herwegh Marco, Regenauer-Lieb Klaus (2015), Boudinage as a material instability of elasto-visco-plastic rocks, in Journal of Structural Geology
, 78, 86-102.
Dielforder Armin, Vollstaedt Hauke, Vennemann Torsten, Berger Alfons, Herwegh Marco (2015), Linking megathrust earthquakes to brittle deformation in a fossil accretionary complex, in NATURE COMMUNICATIONS
, 6, 1-10.
Sheet silicate-rich lithologies are highly abundant in the Earth’s upper and middle crust. In a geodynamic context, they represent important rock types because (i) strain often is localized in these rocks due to their low rock strength at low to intermediate temperature conditions and (2) they serve as important fluid sources owing to water release with progressive recrystallization/ compaction/metamorphic reaction. Improved knowledge on the interplay between fluid release and deformation is rather crucial to better understand what the rheological effect on the formation and evolution of crustal scale deformation (fold and thrust tectonics, shear zones) is. In order to study the aforementioned interplay between deformation and fluid release over a temperature range, we will carry out an interdisciplinary research project in the field of structural geology, metamorphic petrology, rock mechanics and materials science. The project is based on a combination of quantitative fieldwork, quantitative microstructural and geochemical analytics and numerical modeling. The field areas will be situated in the Swiss Alps reaching from the Jura Mountains through the Helvetic Alps till the Penninic front allowing to gain information on changes in the interplay between deformation and fluid release over a temperature range from 80-450°C, i.e. metamorphic conditions of the upper to middle crust. The project is subdivided into the following three parts, each being treated by different persons of our research team:A)Quantitative investigation of the spatial distribution, 3D geometries and the evolution of fluid pathways within the temperature range 80-450°C in sheet silicate-rich rocks located near large-scale shear zones (PhD student A together with collaborators). This part is based on quantitative mapping of fluid pathways along N-S profiles combined with quantitative microstructural and geochemical analyses.B)The 3D quantification of the evolution in porosity and permeability as a function of strain, temperature and sheet silicate content (PhD Student B and PD Dr. A. Berger together with external collaborators). Mapping of key outcrops serves as a base for the quantification of 3D porosity evolution ranging from the submicron to the meter-scale on specific sample series using high-resolution analytical techniques (synchrotron tomography, FIB-FEG-SEM, computer tomography).C)Investigation of the rheology of sheet silicate-rich rocks in natural examples and their description via numerical models (PhD student C and Prof. M. Herwegh together with external collaborators). Numerical modeling approaches using natural strain and stress gages in order to investigate the rheological changes in sheet silicate bearing rocks and their fracturing behavior during fluid release.All three topics are closely related to each other requiring intense interaction and collaboration between the different members of the research team. In addition, the project will benefit from national as well as international collaborations for the different projects parts (e.g. University of Lausanne, Basel University; University of Western Australia). The suggested research project will have a broad impact in different disciplines of fundamental research as there are the localization of strain in sheet silicate-rich rocks, the effect of fluid release on permeability and deformation (fracturing, earthquake nucleation) as well as in applied problems (e.g. radioactive waste deposits, CO2 sequestration, shale gas and deep seated geothermal energy).