Génesis, petrografía y análisis multiespectral de evaporitas en Quebrada Pinte, Alto del Carmen, Región de Atacama
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Fecha
2022
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Profesor/a Guía
Facultad/escuela
Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
El margen occidental de Gondwana durante el paleozoico ha sufrido el impacto y desarrollo de varios terrenos
alóctonos generando en distintas edades la reactivación de la subducción y dando origen a diferentes arcos
magmáticos cercanos a la costa. En la zona de estudio Chilenia proveniente de Laurentia, representa gran relevancia
en el metamorfismo de Migmatitas de Quebrada Seca y siendo parte del basamento representado en Gneises de la
Pampa. Posterior a este evento, a fines del Carbonífero asociado a un nuevo proceso de colisión contra Gondwana
comienza la fase Orogénica San Rafael, reactivando la subducción en el arco y engrosamiento de la corteza, siendo
representada en el área por intrusivos sintectónicos y postectonicos. Posterior a un periodo de estacionario a fines del
Pérmico hasta el Jurásico inferior, comienza la fragmentación de Gondwana en una parte occidental y otra oriental,
dando origen a una extensión y provocando depresiones en el trasarco que en el área fue relleno por material
volcánico continental de la Formación La Totora. La reactivación de la subducción a partir del Jurásico temprano
comienza a partir de la separación de Gondwana, de esta forma se generó un nuevo arco magmático en la actual
Cordillera de la Costa. Cabe destacar que los procesos extensionales en esta etapa se deben a el retroceso negativo de
la trinchera, lo cual provocó grandes cuencas de trasarco siendo rellenas inicialmente por sedimento marino calcáreo
debido a procesos de transgresión y regresión del océano hacia el continente siendo asociado a la Formación Lautaro
y posterior somerización de la cuenca rellena con material volcánico continental de la Formación Algarrobal con
intercalaciones evaporíticas durante el Oxfordiano y secuencias evaporíticas en el Kimmeridgiano, generando
depósitos terrígenos grueso de evaporitas.
The western margin of Gondwana during the Paleozoic has suffered the impact and development of several allochthonous terranes showing at different ages the reactivation of subduction and giving rise to different magmatic arcs near the coast. In the study area Chilenia from Laurentia, it represents great relevance in the metamorphism of Migmatites of Quebrada Seca and being part of the basement represented in Gneises de la Pampa. After this event, at the end of the Carboniferous, associated with a new collision process against Gondwana, the San Rafael Orogenic phase begins, reactivating subduction in the arc and thickening of the crust, being represented in the area by syntectonic and post-tectonic intrusives. After a stationary period at the end of the Permian until the Lower Jurassic, the fragmentation of Gondwana begins in a western and an eastern part, giving rise to an extension and causing depressions in the back-arc that in the area was filled by continental volcanic material from the La Totora Formation. The reactivation of the subduction from the early Jurassic begins from the separation of Gondwana, in this way a new magmatic arc will end in the current Cordillera de la Costa. It should be noted that the extensional processes in this stage are due to the negative retreat of the trench, which caused large back-arc basins to be initially filled by calcareous marine sediment due to processes of transgression and regression of the ocean towards the continent, being associated with the Formation Lautaro and subsequent shallowing of the basin filled with continental volcanic material from the Algarrobal Formation with evaporite intercalations during the Oxfordian and evaporite sequences in the Kimmeridgian, failing thick terrigenous deposits of evaporites.
The western margin of Gondwana during the Paleozoic has suffered the impact and development of several allochthonous terranes showing at different ages the reactivation of subduction and giving rise to different magmatic arcs near the coast. In the study area Chilenia from Laurentia, it represents great relevance in the metamorphism of Migmatites of Quebrada Seca and being part of the basement represented in Gneises de la Pampa. After this event, at the end of the Carboniferous, associated with a new collision process against Gondwana, the San Rafael Orogenic phase begins, reactivating subduction in the arc and thickening of the crust, being represented in the area by syntectonic and post-tectonic intrusives. After a stationary period at the end of the Permian until the Lower Jurassic, the fragmentation of Gondwana begins in a western and an eastern part, giving rise to an extension and causing depressions in the back-arc that in the area was filled by continental volcanic material from the La Totora Formation. The reactivation of the subduction from the early Jurassic begins from the separation of Gondwana, in this way a new magmatic arc will end in the current Cordillera de la Costa. It should be noted that the extensional processes in this stage are due to the negative retreat of the trench, which caused large back-arc basins to be initially filled by calcareous marine sediment due to processes of transgression and regression of the ocean towards the continent, being associated with the Formation Lautaro and subsequent shallowing of the basin filled with continental volcanic material from the Algarrobal Formation with evaporite intercalations during the Oxfordian and evaporite sequences in the Kimmeridgian, failing thick terrigenous deposits of evaporites.
Notas
Memoria (Geólogo)
Palabras clave
Petrografía, Evaporitas, Análisis, Chile, Alto del Carmen