Características sedimentológicas de los sedimentos del Lago Peñuelas, Reserva Nacional Lago Peñuelas, provincia de Valparaíso, región de Valparaíso
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Fecha
2023
Autores
Tobar Castillo, Constanza Andrea
Profesor/a Guía
Facultad/escuela
Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
El presente trabajo comprende un estudio a detalle de los sedimentos del Lago Peñuelas, ubicado en la región de Valparaíso, en el cual producto de la megasequía que ha afectado a la región, la mayoría de sus sedimentos se encuentran expuestos a la superficie. Es por esto que el registro estratigráfico que a la fecha no se encuentra definido, podría ayudarnos a comprender la evolución del lago en los últimos 120 años.
Se identificaron las características sedimentológicas y las facies del depósito, además de determinar una edad relativa para cada unidad sedimentaria y así identificar las características climáticas de depositación de cada unidad. La hipótesis de este trabajo se basa en que el embalse posee registro climático de los últimos 120 años, en donde sus facies reflejarían el registro desde la creación a la fecha.
Se reconocieron ciclos de inundación y se sequía, en donde las facies de inundación se componen principalmente por sedimentos finos y las facies de sequía por sedimentos arenosos con restos de raíces. En base a los ciclos de inundación y sequia se ha calculado que cada ciclo correspondería a una edad máxima de depositación de 5 a 10 años por ciclo. Se reconocen al menos 7 ciclos en base a sus características de sus facies que van desde 1900 a 1985.
En general, el lago presenta 3 ciclos de cambios dramáticos que podrían estar asociados con episodios climáticos, como el fenómeno ENOS.
The present work includes a detailed study of the sediments of “Lago Peñuelas”, located in the Valparaíso region, in which, as a result of the mega-drought that has affected the region, most of its sediments are exposed to the surface. This is why the stratigraphic record, which to date is not defined, could help us to understand the evolution of the lake in the last 120 years. The sedimentological characteristics and facies of the deposit were identified, in addition to determining a relative age for each sedimentary unit and thus identifying the climatic characteristics of deposition of each unit. The hypothesis of this work is based on the fact that the reservoir has a climatic record of the last 120 years, where its facies would reflect the record from creation to date. Flood and drought cycles were recognized, where the flood facies are composed mainly by fine sediments and the drought facies by sandy sediments with remains of roots. Based on the flood and drought cycles, it has been calculated that each cycle would correspond to a maximum depositional age of 5 to 10 years per cycle. At least 7 cycles are recognized on the basis of their facies characteristics, ranging from 1900 to 1985. In general, the lake presents 3 cycles of dramatic changes that could be associated with climatic episodes, such as the ENSO event.
The present work includes a detailed study of the sediments of “Lago Peñuelas”, located in the Valparaíso region, in which, as a result of the mega-drought that has affected the region, most of its sediments are exposed to the surface. This is why the stratigraphic record, which to date is not defined, could help us to understand the evolution of the lake in the last 120 years. The sedimentological characteristics and facies of the deposit were identified, in addition to determining a relative age for each sedimentary unit and thus identifying the climatic characteristics of deposition of each unit. The hypothesis of this work is based on the fact that the reservoir has a climatic record of the last 120 years, where its facies would reflect the record from creation to date. Flood and drought cycles were recognized, where the flood facies are composed mainly by fine sediments and the drought facies by sandy sediments with remains of roots. Based on the flood and drought cycles, it has been calculated that each cycle would correspond to a maximum depositional age of 5 to 10 years per cycle. At least 7 cycles are recognized on the basis of their facies characteristics, ranging from 1900 to 1985. In general, the lake presents 3 cycles of dramatic changes that could be associated with climatic episodes, such as the ENSO event.
Notas
Tesis (Geóloga)
Palabras clave
Sedimentología, Estratigrafía, Chile, Lago Peñuelas, Facies (Geología), Análisis