Rheological structure of the lithosphere in the Mediterranean : new insights from a 3D thermal analysis : ANALYSIS

The enigmatic regional deformation pattern of the Mediterranean region, in which areas subjected to extension, such as Tyrrhenian and the Provencal basins, are embedded in areas subjected to compression and strong crustal thickening, such as the Alps and the Appennine, is the result of a complex interplay of various dynamic processes, acting in synchrony with the regional rheological heterogeneities that are induced by a great variability in crust structure and thermal regime. We present the results of a new detailed thermal analysis, we performed in the Mediterranean with the aim to better constraint the strength of the lithosphere in the area and to emphasize more local rheological heterogeneities, responsible for local deformation features that cannot be ascribed to the regional tectonics. Lithosphere temperature is calculated by means of a 3D finite element model. Vertical strength envelopes through the lithosphere account for both brittle and ductile rocks behavior, according to their composition and thermal state. Our results show that a strong lithosphere paves the Tyrrhenian, with a strongly coupling between crust and mantle at the Provencal Basin and south of the Calabrian Arc, while a relative softer lithosphere characterizes the Marsili Basin, where an local thermal rise occurs.