Quantitative structural analyses and numerical modelling of ...

3. Quantitative analyses of metamorphic microstructures 37Figure 3.7: Example of textural data obtained from EBSD analysed by MTEX andsubsequently imported into PolyLX to obtain microstructural quantitative datawith ELLE code is required. In recent collaboration with leaders in ELLE programming(Mark Jessell - Toulouse, Sandra Piazollo - Stockholm and Paul D. Bons - Tubingen)we achieved a full compatibility between both codes so, that now the microstructuralprocesses can be both simulated and quantified. In close future we plan to test simpledeformation - growth simulations for known thermal histories coupled with detailedstatistical analysis of rock microstructure. Our aim is to define parameters allowing toprecisely characterize the microstructure relationships to stress and temperature as it isdone in metallurgy.In nature factors controlling the active deformation mechanisms and hence the rheologyinclude those that are properties of the deforming material (e.g. composition andmineral assemblage, texture, grain size), and those that are imposed on the system fromoutside (confining pressure, differential stress, temperature and fluid pressure). Thereforewe plan coupling of precise identification of PT evolution of rock carried out throughThermocalc and Perple X codes in collaboration with leading petrologists in the field(Roger Powell (Melbourne), Richard White (Mainz) and Pavla Štípská (Strasbourg))in order to attribute to compositional characteristics of mineral microstructures moreor less precise PT conditions and PT trends. This approach will allow us to search formicrostructures that are unique for given PT conditions but also time of rock residencein given thermal conditions. The latter parameter will be quantified by analyses of interfacialangles that are functions of time of annealing, but also phase spatial distributionsand grain size evolutions.