FOR 741:  Nanoscale Processes and Geomaterials Properties

• Subject Area: Geosciences
• Term: from 2007 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 22341081

Nanometer scale structures in geological materials such as crystal defects, grain- and phase boundaries and small scale chemical zoning patterns may provide insight into the processes, which occur on the atomic or molecular level and control the kinetics of mineral reactions. The processes involved in breaking and establishing bonds at reaction sites and in material transport in between, govern the development of microstructures and textures and this way coin the geodynamic record contained in the phase assemblage and in the fabric of a rock. In addition, they determine how and at what rate bulk rock properties change in response to external forcing and possibly feed back into geodynamic processes. Both, reading the information stored in rock fabrics as well as a better understanding of the feedback between transient bulk material properties and geodynamics require a thorough understanding of the processes underlying phase and fabric change in geological materials.
The objective of this Research Unit is to stimulate coordinated research, which is focused on grain- and phase boundary processes and their implications for reaction kinetics, microstructure development and bulk material properties. This research builds on well established concepts from equilibrium thermodynamics and reaction kinetics, and it makes use of recent advances in analytical and experimental techniques as well as of new theoretical and computational capabilities. The Research Unit aims to integrate expertise from field- and laboratory based researchers in mineralogy, petrology, geochemistry, mineral- and petrophysics as well as from materials science, physics and applied mathematics to generate new competence in geo-materials science.
The expected outcomes of this Research Unit will help to answer long standing questions up to the mechanisms and rates of mineral reactions, the size and life times of chemical and isotopic equilibration domains and the feedback between mineral reactions and mechanical stress. They will help to critically evaluate and improve existing petrological, geochemical and geochronological models, and will contribute to a better understanding of the transient nature of bulk material properties. This will allow refinement of geodynamic models and geophysical tools, and it will foster the understanding of the links between microscopic processes, bulk material properties and the evolution of geological systems in space and time.

• DFG Programme: Research Units
• International Connection: Austria

Projects

• Coordination project of the Research Unit "Nanoscale Processes and Geomaterials Properties" (Applicant Heinrich, Wilhelm )
• Element transport along grain boundaries of synthetic silicate bicrystals: the effect of tilt orientations on transport properties (TP1) (Applicant Heinrich, Wilhelm )
• Fluid assisted mineral replacement processes (Applicant Franz, Gerhard )
• Growth kinetics and texture formation of pyroxene reaction rims in thin films settings (Applicants Milke, Ralf ;  Schorr, Susan )
• Influence of deformation mechanisms on deformation-induced resetting of radiogenic isotope systems (U-Pb, Rb-Sr, Sm-Nd) and homogenization on the grain-scale (TP15) (Applicant Romer, Rolf Ludwig )
• Non-linear diffusion during phase separation and symplectite formation in alkali feldspar: an experimental and modelling approach (TP8) (Applicants Abart, Rainer ;  Heinrich, Wilhelm )
• Polarization effects at grain-boundaries (Applicants Brasse, Heinrich ;  Schilling, Frank Rüdiger )
• Re-equilibration processes in grain-internal domains: The interrelation of mineral reactions and deformation during metamorphism (TP14) (Applicant Habler, Gerlinde )
• Reaction between silica or alkali-rich melts and mafic minerals - small scale kinetic fractionation with applications to global-scale mantle metasomatism (TP11) (Applicant Milke, Ralf )
• Structure and properties of grain and phase boundaries in rocks (Applicant Dresen, Georg )
• The effect of stress/strain-induced texture evolution and grain boundary mobility on reaction rim growth in the wet system MgO-SiO2 (Applicant Rybacki, Erik )
• The effect of water on diffusion-controlled reaction rim growth (TP3) (Applicant Heinrich, Wilhelm )
• The influence of defect structures at reaction interfaces and shear-deformation on reaction rim growth kinetics in the MgO-Al2O3 system (Applicants Abart, Rainer ;  Habler, Gerlinde )

• Partner Organisation: Fonds zur Förderung der wissenschaftlichen Forschung (FWF)
• Spokesperson: Professor Dr. Wilhelm Heinrich
• Deputy: Professor Dr. Rainer Abart