Metamorphism and linked deformation in understanding tectonic processes at varied scales

Abstract

This contribution presents a review exploring some aspects and issues surrounding the links between metamorphism and deformation at different scales. I first discuss the quantification methods of thermodynamics and the parameters able to overcome the kinetic barriers for metamorphic reactions. On the basis of some world's type iconic examples I discuss how metamorphism is likely to portray the thermo-mechanical evolution of lithosphere active zones, thus large-scale tectonic processes. Finally, I present the multiple interactions between metamorphism and deformation at rock and outcrop scales.

Metamorphic Remnants of the Variscan Orogeny across the Alps and Their Tectonic Significance

“…In fact, recent thermomechanical simulations indicate that contrasting metamorphic conditions can simultaneously be observed in different regions of the subduction system [20,205]. The Barrovian field gradient (15-35 • C/km), which is typical for rocks evolving within collisional contexts, developed from Carboniferous to Permian times after the Franciscan gradients or as the re-equilibration of older lower-T relicts (Figure 9b) and is recorded via rocks from all parts of the Alps (Figure 9b).…”

“…The Variscan belt constitutes the skeleton of the European continental crust and, for this reason, is one of the most investigated orogens in the world. The palaeogeographicgeodynamic reconstructions are numerous and contrasted, and the proposed subdivisions into structural domains (e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]) are rendered incomplete by the Meso-Cenozoic "tectonic disturbance" induced by the Betic Cordillera, the Pyrenees, and the Alps (Figure 1). The resolution of the Variscan structural setting of these domains would allow for correlating the central and the southern part of the European Variscides, possibly solving doubts or helping to overcome misfits.…”