Introduction
From south to north we can clearly observe the effects of the D1 compressional deformation with south verging recumbent folds and shear zones affected by a D2 deformation, with strain increasing northward and tectonic transport parallel to the belt. The Paleozoic rocks underwent progressive Barrovian-type metamorphism increasing northward. The classical place where it is well-observable is the Baronie transect. In the Asinara Island and Anglona we can observe the superposition of the high-grade metamorphic complex onto the medium-grade rocks. The effects of HT-LP metamorphism, affecting the Barrovian one, are evident at the microscopic-scale and at the outcrop scale also by the growth of cm- to dm-size andalusite porphyroblasts. The relations among late orogenic plutons, dykes and metamorphytes are clearly exposed in the proposed transects.
During this field trip the classical results of the tectonic and metamorphic studies in the Variscan belt of Sardinia will be shown (Carmignani et al., 1994; Ricci et al., 2004 and references therein) together with the new results reached after intense researches performed in the last few years by the researchers from Pisa University (funded by Italian Ministery of Research and University of Pisa) in collaboration with researchers from Cagliari, Sassari and Siena Universities.
It is worth to note the new structural and geological mapping at 1:10.000 scale of the Asinara island, Anglona and Baronie with the systematic observation of structural elements, the late D1 shear zones related to beginning of exhumation, the relationship between D2 transpressional deformation and the exhumation of the basement, the datation by Ar-Ar of the D1 and D2 deformation events, the recognition, for the first time, of sinistral shear zones along the Posada-Asinara Line and the change in the classical zonation of Barrovian metamorphism in the Baronie due to the finding of staurolite+biotite appearance several kilometres southward with respect to the position of the classical isograd.
However, some important aspects in the tectonic evolution of the Sardinian Variscan belt are still matter of debate such as: the existence of a suture, the pre-Variscan evolution and the presence of a pre-Variscan basement and, finally, the position of the Corsica-Sardinia microplate during the upper Paleozoic and its correlations with the other fragments of the Southern Variscan belt.