Litostratigrafia del Cambroordovicià de les valls de Ransol i d'Incles - Andorra

(ENG) The Ransol and Incles valleys, both belonging to the parish of Canillo, represent the southern branch of the Ospitalet massif. This massif is a part of the Hercynian basement of the Pyrenees, basically built up by Cambroordovician materials affected by Hercynian tectonics and low or medium grade metamorphism. Cambroordovician materials can be divided in two distinguishable lythological units: at the bottom, augengneiss, with a metasedimentary series on top. The whole series adopts a dome shape, with the gneiss in the core. This study basically focuses on this latter unit, intending to describe and characterize it in both valleys (Ransol and Incles) in order to compare results obtained with previous studies carried out in this zone. In this metasedimentary series, quite monotonous, several intercalations can be distinguished, mainly quarsitic levels. Both, the origin and correlation of these levels around the zone have historically been the object of quite different explanations. Detailed mapping of the zone and microscope lythological studies were therefore made to distinguish the different levels. The results of the field study on different lythologic types and their distribution in this zone allowed stratigraphic columns, geological cross-sections and a geological map to be obtained. This map was compared to previous maps of the same zone.