role of shear heating in intracontinental inverted metamorphism: Inference from a thermo-kinematic parametric study. Tectonophysics, Elsevier, 2013, 608, pp.812-831. 10.1016/j.tecto.2013 1 Major role of shear heating in intracontinental inverted metamorphism:Inference from a thermo-kinematic parametric study. AbstractInverted metamorphism corresponds to the stacking of high-temperature metamorphic units structurally on top of lower-temperature units and is commonly observed along main thrusts in major orogens. Yet, in spite of many existing models, the origin and preservation of the metamorphic inversion in intracontinental collision belts is still debated. In this study, we use a crustal-scale 2D thermo-kinematic model in order to investigate the key parameters controlling the inversion of the geothermal gradient at crustal scale. Our results confirm that the kinematic framework strongly impacts the thermal evolution around the thrust. Erosion velocity and thermal conductivity of rocks are two parameters that control the spatial location of the thermal perturbation and the intensity of inversion, respectively. However, even in extreme kinematic configurations, i.e., convergence velocities > 3cm.yr 3

International audienceThe thermal evolution around shear zones is controlled by three major thermal processes: diffusion, advection and shear heating. We present a dimensional analysis to quantify, to first-order, the relative contributions of these three processes to the thermal evolution around lithospheric-scale shear zones. We consider eleven parameters that control the kinematics, the three-dimensional (3-D) geometry, the initial thermal structure and the average strength of the shear zone. Three dimensionless parameters are presented to quantify the relative contributions of the three thermal processes. We validate the dimensional analysis with 2-D thermo-kinematic numerical models. The applicability of the dimensional analysis to any kind of shear zone (i.e., thrust, normal-slip and strike-slip shear zones) makes it a useful tool that is complementary to previous numerical and analytical studies. Finally, thrust-type shear zones are used to illustrate how the three thermal processes control the thermal evolutio