TS2.6Stress and strain patterns and mechanisms of micro-meso deformation in folded rocks
|Convener: Olivier Lacombe | Co-Conveners: Stefano Tavani , Ruth Soto|
Fold evolution is still to date mainly described in terms of geometry and kinematics; most studies relies upon analytic and numerical analyses that are based on the present-day geometry of folded strata and geometrical assumptions such as thickness and length preservation. However, the deformation mechanisms that accommodate internal strain within folded strata at the meso- to microscopic scales remain to be properly linked to such geometric/kinematic macroscopic evolution.Comprehensive understanding of the relationships between the folding process and the development in time and space of fold-related structures is of great importance for both academic and industrial purposes since accurate description and simulation of hydrocarbon and water reservoirs require a good knowledge of mechanical behaviour of rocks when they are folded and fractured. At the macroscale, deformation in a fold is mainly accommodated by flexural slip, localization of deformation along fault planes and formation of macroscopic fracture sets; at the microscale, several structural mechanisms are active, such as pressure-solution cleavage and grain-scale deformation (e.g., mechanical compaction, inter/intra grain fracturing, twinning in calcite grains); however, their spatial distribution in the different fold sectors, their succession through time, their relative importance in the deformation of folded strata and the relationship between the development of such structures and the evolution of orientations/magnitudes of tectonic stresses during the different deformation stages recognized during fold development remained poorly constrained.This session aims at making the point about our understanding of the relationships between the folding process, the development in time and space of fold-related structures, the history of strain acquisition from the macroscopic to the microscopic scales in folded strata and the orientations and magnitudes of (local) stresses associated with fold evolution. Works dealing with the analysis of meso- and microstructures and other indicators of internal deformation, like AMS, are welcome.