Cartografía Geológica y caracterización microestructural de los cinturones cizallados occidentales ubicados al este de Pungalapamba, sureste de Riobamba.

Abstract

The study area is located to the east of the town of Pungalapamba in the Cordillera Real, in the central Andes of Ecuador, approximately 17 km southeast of the Riobamba city, in the Chimborazo province. The Cordillera Real of Ecuador constitutes a belt of metamorphic rocks that forms the limit of the eastern of the Andes Mountains whose origin and formation require detailed cartographic and chronostratigraphic studies in each of its segments. In the present work, it was referred to the characterization of the Chigüinda, Tres Lagunas, Alao, Peltetec, Maguazo, Alao-Paute, San de Sali, Río Daldal, Yunguilla, Volcanic Quishuar - Las Minas units and local intrusives in macroscopic and microscopic analysis, also geological cartography, petrographic and microstructural analysis of the unit rocks of the area located to the east of the town of Pungalapamba in order to propose a local geological and structural model. The Chigüinda and Tres Lagunas unit were characterized as a mixture of internally fragmented rocks and mixed by tectonic movements implied a particular mixing process known as tectonic mélange, as product of many events. Also, Chigüinda presents several foliations and crenulation cleavage; as the Tres Lagunas, in samples were possible to see blue quartz and kink bands. The existence of an important folding event in the Guamote sequence and Maguazo unit and a subsequent shearing event related to the exhumation of the Peltetec ophiolitic complex, would indicate a possible relationship with the accretionary kinematics of the Piñón-Pallatanga terranes (Cordillera Occidental), which would be summarized in the first instance as a period of collision and net accretion (folding), after a movement and migration of said terrains to the NNE (shearing).