Deformation and displacement from shear zone patterns in the Variscan upper crust, Jebilet, Morocco

In central Jebilet (Moroccan Variscan belt), post-Visean deformation is acc ommodated by a significant amount of displacement along conjugate ductile t o brittle shear zones. Ductile shearing is concentrated in thermally soften ed aureoles around magmatic intrusions, which are distributed along crustal discontinuities. Far from the intrusions, ductile deformation evolves into brittle conditions. Strain patterns have been investigated mapping finite strain trajectories, strain intensity gradients and syntectonic contact met amorphism. Geometry and kinematics of deformation reflect the influence of both north west-southeast regional shortening and thermal softening around magmatic pods. The asymmetry of the structural pattern reflects the bulk st rain regime and characterises a non-coaxial transcurrent deformation. Compu ting the variations of the shear strain along conjugate shear zones allows the calculation of shear displacement at the regional scale. (C) 2001 Elsev ier Science Limited. All rights reserved.