Cordillera Real: metamorphism variation along The Atillo-Normandía route

Abstract

The Atillo - Normandy study area belongs to the Guamote - Macas highway, located in the Cordillera Real, it has a high susceptibility to mass removal phenomena due to the instability of the terrain and intense rainfall in this area. The basement of the Cordillera Real corresponds to metamorphic and plutonic rocks, which have been affected by tectono-metamorphic events during the Mesozoic, causing local variations in the metamorphic grade of lithological sequences of the region. Several authors have established the highest metamorphic grade is in the center of the Cordillera and decreases towards the flanks. When determining lythology of the Atillo - Normandy route, defining: paragenesis and the tipomorphic mineral, three metamorphic facies was established: prehnita-pumpellyite, green schist and amphibol epidote. The last one it’s reflected in a greenstone with garnets, this rock has the highest metamorphic grade, therefore, marks the central axis of the variation of metamorphism. This rock has not been described in previous studies of Cordillera Real, through DRX analysis it was determined, that this rock has a basaltic protolith, furthermore, suffered a process of uralitization that is a characteristic process of retrometamorphism.