Ambiente sedimentario deposicional de la Formación San Eduardo (eoceno medio), al suroeste de San Antonio, cantón Playas, provincia del Guayas
Fecha
2021-03
Título de la revista
ISSN de la revista
Título del volumen
Editor
Facultad de Ciencias Naturales. Universidad de Guayaquil
Resumen
La formación San Eduardo (Eoceno Temprano - Eoceno Medio) constituida litológicamente por calizas (compactas, turbidíticas bien estratificadas y contenida de granos arrecifales) y lutitas. La caliza San Antonio que aflora en el cantón Playas de la provincia del Guayas, en la cual no se han llevado a cabo muchas investigaciones científicas, debido a que hay poca información geológica de estas rocas. Sin embargo, a esta sección se la toma como parte de la formación San Eduardo. El objetivo de este trabajo de investigación es definir la composición petrográfica, bioestratigráfica y ambiente deposicional. Se estudiaron cuatro afloramientos y dieciséis láminas delgadas para precisar el trabajo investigativo. Se utilizaron modelos de clasificación para rocas carbonáticas y tipos de microfacies, para establecer su ambiente de deposición. Su litología corresponde a rocas calciruditas, calcarenitas, y lodolitas calcáreas. Petrográficamente la caliza San Antonio comprende rocas packstone bioclástico (bioesparita) y grainstone bioclástico (bioesparita). La edad relativa es Eoceno Medio, comprendida entre los pisos Luteciense al Bartoniense, debido a la identificación de los foraminíferos planctónicos Globorotalia sp., Globorotalia Bolivariana, Turborotalia sp. y Chilomguenbelina Martini. El paleoambiente sedimentario deposicional es de Plataforma Retrabajada a Plataforma Restringida; y de Rampa Media a Rampa Interna.
The San Eduardo formation (Early Eocene - Middle Eocene) lithologically constituted by limestones (compact, well-stratified turbiditic and containing reef fragments) and shales. The San Antonio limestone that outcrops in the Playas canton of the Guayas province, where not many scientific investigations have been carried out, since there is little geological information about these rocks. Nevertheless, this section is taken as part of the San Eduardo formation. The objective of this research is to define the petrographic and biostratigraphic composition; and depositional environment. Four outcrops and sixteen thin sections were studied to clarify the investigative work. The classification models for carbonate rocks and the types of microfacies were used to establish their depositional environment. Its lithology corresponds to calcirudite, calcarenite, and calcareous mudstone rocks. Petrographically, the San Antonio limestone are of bioclastic packstone (bioesparite) and bioclastic grainstone (bioesparite). The relative age is Middle Eocene, between the Lutetian to Bartonian stages, due to the identification of the planktonic phoraminifera Globorotalia sp., Globorotalia Bolivariana, Turborotalia sp. and Chilomguenbelina Martini. The depositional sedimentary paleoenvironment is Reworked Platform to Platform Restricted from Medium to Internal Ramp.
The San Eduardo formation (Early Eocene - Middle Eocene) lithologically constituted by limestones (compact, well-stratified turbiditic and containing reef fragments) and shales. The San Antonio limestone that outcrops in the Playas canton of the Guayas province, where not many scientific investigations have been carried out, since there is little geological information about these rocks. Nevertheless, this section is taken as part of the San Eduardo formation. The objective of this research is to define the petrographic and biostratigraphic composition; and depositional environment. Four outcrops and sixteen thin sections were studied to clarify the investigative work. The classification models for carbonate rocks and the types of microfacies were used to establish their depositional environment. Its lithology corresponds to calcirudite, calcarenite, and calcareous mudstone rocks. Petrographically, the San Antonio limestone are of bioclastic packstone (bioesparite) and bioclastic grainstone (bioesparite). The relative age is Middle Eocene, between the Lutetian to Bartonian stages, due to the identification of the planktonic phoraminifera Globorotalia sp., Globorotalia Bolivariana, Turborotalia sp. and Chilomguenbelina Martini. The depositional sedimentary paleoenvironment is Reworked Platform to Platform Restricted from Medium to Internal Ramp.
Descripción
Palabras clave
EOCENO MEDIO, FORAMINÍFEROS PLANCTÓNICOS, AMBIENTE DEPOSICIONAL, MICROFACIES