Petrogénesis de afloramientos en el sector norte de la localidad de San Andrés, cantón Chinchipe, provincia de Zamora Chinchipe
Fecha
2021
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Facultad de Ciencias Naturales. Universidad de Guayaquil
Resumen
El objetivo de la presente investigación fue interpretar la procedencia de las rocas aflorantes al Norte de la localidad de San Andrés, mediante petrografía y análisis geoquímicos para elementos mayoritarios, trazas y tierras raras; se obtuvieron los resultados a través de la descripción de nueve muestras, mismas que fueron descritas macroscópicamente y microscópicamente. Se seleccionaron cinco muestras para láminas delgadas y tres muestras para análisis geoquímicos. La metodología que se fundamentó en la interpretación petrográfica, consistió en un análisis modal basado en el diagrama de Streckeisen para rocas plutónicas. Para la interpretación geoquímica, se realizó el análisis de multielementos por fusión con metaborato y espectrometría por emisión atómica en los laboratorios Inspectorate Services Perú. Se utilizaron diagramas para multielementos como: diagramas Ternarios de Total Alkalis Sílica, para magmas toleíticos y calco- alcalinos, de discriminación tectónica y tipos de granitoides. Por medio de los cuales se identificaron dos tipos de rocas correspondientes a granodioritas y cuarzolita. Para las granodioritas se determinó una serie magmática calco- alcalina y para la cuarzolita la serie magmática toleítica. Para las tres rocas se interpretó que tienen un mismo ambiente tectónico de procedencia VAG (Granitos de arco volcánico). Las granodioritas estudiadas son granitoides provenientes del manto y corteza interna (Tipo I) y la cuarzolita es causada por la fusión parcial de rocas de la corteza superior (Tipo S).
The objective of the present investigation was to interpret the origin of the outcropping rocks to the North of the San Andrés locality, by means of petrography and geochemical analysis for majority elements, traces and rare earths; The results were obtained through the description of nine samples, which were described macroscopically and microscopically. Five samples were selected for thin sheets and three samples for geochemical analysis. The methodology that was based on the petrographic interpretation consisted of a modal analysis based on the Streckeisen diagram for plutonic rocks. For the geochemical interpretation, the analysis of multielements by fusion with metaborate and atomic emission spectrometry was carried out in the Inspectorate Services Peru laboratories. Diagrams were used for multi-elements such as: Ternary diagrams of Total Alkalis Silica, for toleitic and calco-alkaline magmas, for tectonic discrimination and types of granitoids. By means of which two types of rocks corresponding to granodiorites and quartzolite were identified. A chalco- alkaline magmatic series was determined for granodiorites and the toleitic magmatic series for quartzolite. For the three rocks it was interpreted that they have the same tectonic environment of VAG origin (volcanic arc granites). The granodiorites studied are granitoids from the inner mantle and crust (Type I) and quartzolite is caused by the partial fusion of rocks from the upper crust (Type S). Keywords: Geochemical, petrographic, VAG.
The objective of the present investigation was to interpret the origin of the outcropping rocks to the North of the San Andrés locality, by means of petrography and geochemical analysis for majority elements, traces and rare earths; The results were obtained through the description of nine samples, which were described macroscopically and microscopically. Five samples were selected for thin sheets and three samples for geochemical analysis. The methodology that was based on the petrographic interpretation consisted of a modal analysis based on the Streckeisen diagram for plutonic rocks. For the geochemical interpretation, the analysis of multielements by fusion with metaborate and atomic emission spectrometry was carried out in the Inspectorate Services Peru laboratories. Diagrams were used for multi-elements such as: Ternary diagrams of Total Alkalis Silica, for toleitic and calco-alkaline magmas, for tectonic discrimination and types of granitoids. By means of which two types of rocks corresponding to granodiorites and quartzolite were identified. A chalco- alkaline magmatic series was determined for granodiorites and the toleitic magmatic series for quartzolite. For the three rocks it was interpreted that they have the same tectonic environment of VAG origin (volcanic arc granites). The granodiorites studied are granitoids from the inner mantle and crust (Type I) and quartzolite is caused by the partial fusion of rocks from the upper crust (Type S). Keywords: Geochemical, petrographic, VAG.
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GEOQUÍMICA, PETROGRÁFICA, VAG