Publication: La tectónica alpina en el SO peninsular (España)
Loading...
Full text at PDC
Publication Date
2016
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
Sociedad Geológica de España.
Citations
Exportar
Abstract
La tectónica alpina en el SO peninsular está caracterizada por cabalgamientos E-O a ENE-OSO y desgarres sinestrales NE-SO que dan lugar a la formación de cuencas sedimentarias E-O. El estudio de la mineralogía de la fracción < 2μm del relleno sedimentario de las cuencas de Coria, Cañaveral y Guadiana muestra la existencia de tres secuencias deposicionales. La Secuencia Deposicional Inferior, discordante sobre el basamento, presenta una asociación mineralógica illita(predominante)-caolinita-esmectita y solo se ha encontrado en la Cuenca del Guadiana. Su formación estaría relacionada con la formación de pequeñas cuencas limitadas por fallas E-O. La Secuencia Deposicional Superior se dispone sobre la secuencia anterior y sobre el basamento. La asociación mineralógica característica es esmectita(predominante)-illita-caolinita. Se encuentra en todas las cuencas estudiadas. Representa abanicos aluviales colaescentes cuyo espesor disminuiría hacia el sur. La actividad tectónica fractura la zona creando cuencas que se rellenan con los sedimentos preexistentes y siguen evolucionando controladas por las fallas de los bordes. La Unidad Culminante está relacionada con la actividad de las fallas de los bordes septentrionales de las cuencas. Por último estas estructuras controlan la geometría de la red de drenaje actual provocando la orientación E-O de los cursos principales y los cambios de trayectoria cuando encuentran relieves creados por los desgarres NE-SO.
Alpine tectonics on the SO of the Iberian Peninsula develops two main family fault: NE-SW strike-slip left-handed faults and E-O to ENE-OSO thrusts located at the basins margins. Basins show a main E-O trend. A detailed study of clay mineral composition (<2 μm) in 229 samples collected in Coria, Cañaveral and Guadiana basin. The Lower Depositional Sequence (LDS) lies unconformable over basement rocks. Its mineralogical association is illite(predominant)-kaolinite-smectite. It has been found only in the Guadiana Basin, infilling small E-W grabens. Upper Depositional Sequence (UDS) forms widespread deposits lying over LDS or basement rocks. Its mineralogical association is smectite(predominant)-illite-kaolinite. It should represent coalescing alluvial fans whose thickness decrease to the south. Tectonic activity begin and is more intense in the northern area, where conglomerates dominate; deformation migrates to the south and develop small basins filled with pre-existing sediments that evolve separately. Kaolinite is the clay mineral characteristic of the Culminating Unit. This unit is related to faults basins borders activity. E-O to NE faults control the drainage network. Main fluvial courses follow the basins main axis trend (~E-O) experiencing changes in their path when they found block-faulted uplifted and must deviate. This is the case of the Guadiana River when it arrives at the Messejana-Plasencia Fault old scarp.
Alpine tectonics on the SO of the Iberian Peninsula develops two main family fault: NE-SW strike-slip left-handed faults and E-O to ENE-OSO thrusts located at the basins margins. Basins show a main E-O trend. A detailed study of clay mineral composition (<2 μm) in 229 samples collected in Coria, Cañaveral and Guadiana basin. The Lower Depositional Sequence (LDS) lies unconformable over basement rocks. Its mineralogical association is illite(predominant)-kaolinite-smectite. It has been found only in the Guadiana Basin, infilling small E-W grabens. Upper Depositional Sequence (UDS) forms widespread deposits lying over LDS or basement rocks. Its mineralogical association is smectite(predominant)-illite-kaolinite. It should represent coalescing alluvial fans whose thickness decrease to the south. Tectonic activity begin and is more intense in the northern area, where conglomerates dominate; deformation migrates to the south and develop small basins filled with pre-existing sediments that evolve separately. Kaolinite is the clay mineral characteristic of the Culminating Unit. This unit is related to faults basins borders activity. E-O to NE faults control the drainage network. Main fluvial courses follow the basins main axis trend (~E-O) experiencing changes in their path when they found block-faulted uplifted and must deviate. This is the case of the Guadiana River when it arrives at the Messejana-Plasencia Fault old scarp.