Análisis Tectono-Estratigráfico de la Cordillera Costera entre las poblaciones de Jipijapa y La Rinconada

Abstract

The segment of Coastal Range between the villages of Jipijapa and La Rinconada is constituted of Cretaceous igneous rocks which form the basement and sedimentary sequence of different ages that originate in the Late Cretaceous to the Lower Miocene. The petrographic and structural analysis carried out in this study have allowed clearly defined six lithological units, which were deposited in different environments. The dominant regional tectonics reflects structures with directions average North-South parallel to the direction of the oceanic trench in this sector of Ecuador. The main deformation event is the product of extensive and compressive stresses; the extensive stresses are presented as normal faults with directions North – South that affect the Cretaceous units Piñon and Cayo, and the compressive stresses are the product of the accretion of these formations toward the continent, causing folding of the same. The second deformation event is controlled by the Jipijapa reverse fault, which is the product of compressive stresses in the East - West direction, these stresses originated from the Upper Miocene as a result of the increase in the convergence speed of the Nazca Plate.