A Hercynian suture zone in Sardinia: geological, geochemical evidence

The Hercynian basement of Northern Sardinia consists of two main tectonometamorphic complexes: the Southern Paleozoic Low to Medium Grade Metamorphic Complex (LMGMC) and the Northern (Precambrian ?) High Grade Metamorphic Complex (HGMC). These complexes are separated by the "Posada-Asinara Line' which is a several kilometer-wide mylonitic belt consisting of micaschist, paragneiss and quartzite. The northern Sardinia basement can be interpreted as a continental collisional zone with the "Posada-Asinara Line' representing a suture zone squeezed between a crustal nappe (HGMC), which represents the overthrust continental margin, and the inner portion of the Variscan orogenic wedge, which represents the underthrust continental margin with its Paleozoic cover (LMGMC). Geological and geochemical evidence indicate that the "Posada-Asinara Line' may be considered as part of the South European Hercynian Suture Zone. -from Authors