Evidencias hidrológicas y geomorfológicas de cambios en los estilos fluviales de la cuenca del río Laja, VIII región del Biobío, Chile
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Fecha
2020
Autores
Profesor/a Guía
Facultad/escuela
Idioma
es
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Editor
Universidad Andrés Bello
Nombre de Curso
Licencia CC
Licencia CC
Resumen
Los procesos geomorfológicos volcánicos, glaciares y fluviales, hacen del río Laja un lugar
de amplio interés para la realización de una investigación geológica. En este estudio, se
analizaron rasgos erosivos y deposicionales, asociando facies sedimentarias, distribución
litológica, la caracterización hidrológica que consideró parámetros morfométricos,
morfológicos y erosivos, junto a la consideración de variables climatológicas.
Para desarrollar la investigación se utilizaron herramientas satelitales, programas
computacionales ArcMap 10.8 y Qgis 3.14, parámetros de erosión e información proveniente
de la DGA y CIREN.
El análisis morfológico reveló dos transiciones de estilo fluvial. El curso superior presentó
una morfología anastomosada de alta sinuosidad, los tramos medios una morfología
meándrica con sinuosidad variable y el tramo terminal una morfología trenzada de sinuosidad
nula y entrelazamiento elevado.
Los knickpoint más abruptos, se originaron por factor litológico donde la Fm. Banco del Laja
es más susceptible a la erosión laminar del río. Los knickpoint del segmento intermedio
estaban ligados a un cambio de pendiente con cambios en el patrón de drenaje, lo que sugiere
una participación de la tectónica regional junto a la influencia de estructuras ciegas. Los
knickpoint orientales tienen morfología suavizada y había estrías glaciares que indicaron la
influencia de glacio-eutatismo junto a estructuras que ha estado en constante debate.
Los valores altos de índices de erosión coincidieron con la erosión del piedemonte andino y
con la distribución de los knickpoint más abruptos con poca influencia antrópica. Los
cambios morfológicos del río obedecen a variaciones de caudal, tipo de sedimento y
pendiente del lecho.
The volcanic, glacial, and fluvial geomorphological process make the Laja river a great place for conducting an interest geological research. In this study, erosive and depositional features were analyzed, associating sedimentary facies, lithological distribution, hydrological characterization that considered morphometric, morphological, and erosive parameters with the consideration of climatological variables. To develop the research, satellite tools, computer programs like ArcMap 10.8 and Qgis 3.14, erosion parameters and were use information from the DGA and CIREN. Morphological analysis revealed two river-style transition. The upper course presented an anastomosed morphology of high sinuosity, the middle sections a meander morphology with variable sinuosity and terminal section a braided morphology of zero sinuosity and high entanglement. The most abrupt Knickpoints were originated by a lithological control factor where the Bancos del Laja Formation is more susceptible to laminar erosion from the river. The Knickpoint of the intermediate segment were linked to a change in slope with changes in the drainage pattern, which suggests a participation of regional tectonics with the influence of blind structures. The eastern Knickpoints have smoothed morphology and there were glacial streaks that indicated the influence of glacio-eustatic alongside structures that has been in constant debate. The high values of erosion parameters coincided with the erosion of the Andean foothills and the distribution of the most abrupt knickpoints with anthropic influence. The morphological changes of the Laja river are due to variations in flow, type of sediment and slope of the basin.
The volcanic, glacial, and fluvial geomorphological process make the Laja river a great place for conducting an interest geological research. In this study, erosive and depositional features were analyzed, associating sedimentary facies, lithological distribution, hydrological characterization that considered morphometric, morphological, and erosive parameters with the consideration of climatological variables. To develop the research, satellite tools, computer programs like ArcMap 10.8 and Qgis 3.14, erosion parameters and were use information from the DGA and CIREN. Morphological analysis revealed two river-style transition. The upper course presented an anastomosed morphology of high sinuosity, the middle sections a meander morphology with variable sinuosity and terminal section a braided morphology of zero sinuosity and high entanglement. The most abrupt Knickpoints were originated by a lithological control factor where the Bancos del Laja Formation is more susceptible to laminar erosion from the river. The Knickpoint of the intermediate segment were linked to a change in slope with changes in the drainage pattern, which suggests a participation of regional tectonics with the influence of blind structures. The eastern Knickpoints have smoothed morphology and there were glacial streaks that indicated the influence of glacio-eustatic alongside structures that has been in constant debate. The high values of erosion parameters coincided with the erosion of the Andean foothills and the distribution of the most abrupt knickpoints with anthropic influence. The morphological changes of the Laja river are due to variations in flow, type of sediment and slope of the basin.
Notas
Tesis (Geólogo)
Palabras clave
Chile, Río Laja, región del Biobío, Cambios Climáticos, Falla Inversa (Geología), Inundaciones Fluviales, Procesos geomorfológicos volcánicos y glaciares