Evolució del metamorfisme en la transversal Ollo de Sapo - Sinforme de Vivero - Domo de Lugo (NE del macís Hercinià de la península Ibèrica). Model tèrmic i mecanismes de la transformació Andalucita =

The aim of this project is to obtain thermal models of two type metamorphic areas (N Galicia and Eastern Pyrenees) of theVariscan orogen with a good previous structural, geochemical and petrological knowledge. Both areas show high thermal local gradients related to igneous intrusions as well as other differential features such as: in Galicia replacement of andalusite by kyanite in synforms formed after the main regional folding phase; in the Pyrenees overlapping of thermal episodes related to multiple intrusion in the structrual domes. The starting points are the detailed study of the structural relations and of the mineral assemblages in selected areas and its precise timing in order to make a model with heat advection in different moments along the sinking in synforms (Galicia) or uprising in antiforms (Pyrenees). The goal of the thermal model is to predict the time variation of the geotherms according to different preset parameters, as heat source and its morphological and dynamic characteristics as well as the value of pressure in each stadium. In Galicia a second point of interest is the detailed studyj of the andalusite = kyanite reaction and the simultaneous compositional changes int he chl-cld-ms accompanying assemblage. Quantification of PT conditions linked to this reaction will help to establish the PT conditions of the thermal model. In the Eastern Pyrenees the key points are the detailed relations between the intrusions next to or inside the domes. This implies a precise determination of PTt paths where the effect of thermal metamorphism can be discriminated from regional metamorphism. The structural and chronological study of the intrusions will allow us to locate them with regard to regional metamorphism and to establish a thermal model. On its turn this modelling will permit to test the previous hypotheses, mainly referred to the thermal gradient geometry