Abstract
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 intended research builds on research that has been accomplished during the first funding period of FOR 741 and which can be grouped into four broad categories including (1) atomic structure, thermodynamic and kinetic properties of grain boundaries, (2) diffusion in polycrystals, (3) exsolution in mineral systems and (4) fluid assisted mineral replacement. From this work several new scientific questions have emerged, which provide the basis for further research. In the second funding period the entire portfolio of the established topical fields will be pursued. In addition, new aspects on how grain- and phase boundaries are generated in the course of homogeneous and heterogeneous nucleation and how the network of grain and phase boundaries may evolve during thermally and stress induced re-crystallization will be addressed. The existing focus on experimentation and theoretical work will be complemented by studies on natural material and applied mineralogy. This requires that new expertise is integrated into the team, which will be accomplished by bringing in research groups from the University of Vienna through the D-A agreement among DFG and FWF.
The objective of this proposal is to stimulate coordinated research keeping the focus on geo-materials research. This initiative will intensively make use of recent advances in analytical and experimental techniques as well as of new theoretical and computational capabilities. The proposal aims to integrate expertise at the highest international level from field and laboratory based researchers in mineralogy, petrology, geochemistry, and structural geology as well as from materials science, physics, and applied mathematics to generate new competence in geo-materials science. The expected outcomes of this project 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.
