Person: Muñoz Martín, Alfonso
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First Name
Alfonso
Last Name
Muñoz Martín
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Geodinámica, Estratigrafía y Paleontología
Area
Geodinámica Interna
Identifiers
101 results
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Now showing 1 - 10 of 101
Item Glacial geomorphology of the High Gredos Massif: Gredos and Pinar valleys (Iberian Central System, Spain)(Journal of Maps, 2020) Carrasco González, Rosa María; Soteres, Rodrigo L.; De Pedraza Gilsanz, Javier; Fernandez-Lozano, Javier; Turu, Valentí; López-Sáez, Jose Antonio; Karampaglidis, Theodoros; Granja Bruña, José Luis; Muñoz Martín, AlfonsoWe present a detailed geomorphological map of the landform assemblages originated by the two major paleoglaciers of the Sierra de Gredos mountain range in the Spanish Iberian Central System. Based on previous works, our map focused on the features formed by Gredos and Pinar paleoglaciers during the last glaciation and subsequent glacial events. Based on a remote sensing analysis and exhaustive field surveys, we identified with great accuracy the local distribution of glacial, periglacial, mass movement, structural, fluvial, and lacustrine features. We recognized three main glacial geomorphological formations representing: (i) the maximum glacial extension reached (peripheral deposits); (ii) the culmination of glacial conditions (principal moraines) and (iii) the local glacial withdrawal (internal deposits). Our map offers a renewed spatial framework on which to conduct higher-resolution glacial chronologies, especially of Late Glacial and Holocene glacial activity, providing key information for performing future paleoclimatic reconstructions of the northern hemisphere mid-latitudes.Item Sobre el origen de la asimetría en el patrón general del relieve en el interior de la Península Ibérica: nuevos resultados obtenidos mediante modelación análoga(Geogaceta, 2010) Fernández Lozano, Javier; Sokoutis, Dimitrios; Willingshofer, Ernst; Muñoz Martín, Alfonso; De Vicente Muñoz, Gerardo; Cloetingh, SierdAnalogue modelling contributes to the interpretation of lithosphere scale folds in Iberia as a result of largescale convergence during Oligocene-Miocene times between the Iberian and European Plates. Different tectonothermal events affected the microplate since late Paleozoic and resulted in lateral strength variations of the Iberian lithosphere. An old and cold lithosphere, Variscan in age, can be found in the westernmost part of Iberia whereas a relative weak and hot Mesozoic lithosphere affected by episodes of rifting and basin inversion during Mesozoic- Tertiary times covers the area of the Iberian Chain. Our study aims at deciphering whether deformation and topography evolution in Iberia are related to lateral strength variations and/or the inherited structural grain stemming from Variscan deformation. We also have studied the strength of the lithosphere to gain insights into the effects of rheological variations related to local thrusting or primary strength variations along the Iberian lithosphere.Item Controles tectónicos y estructurales de la incisión fluvial en el centro-oeste de la Cuenca del Duero, NO de Iberia(Geogaceta, 2007) Antón López, Loreto; Muñoz Martín, AlfonsoThe present work approaches incision rates quantification of Duero River in the central- west par t of Iberia and implications of tectonics in the evolution and change of drainage patterns. For this aim we calculate incision rates from the two main geomorphological surfaces defined in the area. Comparing fluvial incision rates and fracture pattern a strong structural control is shown; either in the orientation of drainage network, either in the incision rates distribution. Drainage pattern shows two main orientations, NW-SE following the hercinian structure of the area and NE-SW to N-S matching with the main fracture sets (Duero, Almendra, Almeida-Valderaduey faults, as example). Fluvial incision is mostly controlled by the great faults and faults systems NE-SW to N-S oriented.Item Aplicación del método de resistividades con SEV para la caracterización hidrogeológica de la cuenca de Dajla (Argelia)(Geogaceta, 2010) Torres López, Sara; Muñoz Martín, Alfonso; Jiménez Díaz, Alberto; Ahmed, Baba; De lorenzo, Javier; García López, Cristina; Olaiz Campos, Antonio JoséThe aim of this study is the hydrogeological exploration and characterization using Geophisical surveying in the vicinity of Dakhla Basin (Algeria). To that end, it has been used the method of resistivities through Vertical Electric Sounding (VES) on a campaign carried out in April 2009. The work included 19 VES, which have been calibrated with existing wells and with field geological observations. The results have allowed the characterization of Tertiary deposits as well as Ordovician sandstones. With these data, it has been possible to identify the position and thickness of a shallow salty aquifer, and the roof of a deep freshwater aquifer developed on the Ordovician sandstones. The integration of the geometry of the aquifers with the resistivity values obtained in the Ordovician sandstones has allowed the location of a favorable area for the situation of a new well.Item Quantifying the erosional impact of a continental-scale drainage capture in the Duero Basin, northwest Iberia(Quaternary Research, 2018) Antón López, Loreto; Muñoz Martín, Alfonso; De Vicente Muñoz, GerardoFormerly closed drainage basins provide exceptional settings for quantifying fluvial incision and landscape dissection at different time scales. Endorheic basins trap all the sediment eroded within the watershed, which allows estimates of post–basin opening erosion patterns. The Duero Basin was a former closed basin and is presently drained by the Duero River into the Atlantic Ocean. During the Cenozoic, the basin experienced a long endorheic period, marked by the formation of continental carbonates and evaporites. The retrogressive erosion of the Atlantic drainage coming from the Portuguese coast subsequently captured the internal drainage, and significant fluvial dissection occurred. Presently, the basin contains a relatively well-preserved sedimentary fill. Gridding and surface fitting in this paper provide the first attempt to reconstruct the surface of the top of the former endorheic sedimentary sequence to quantify the erosional impact of the basin opening. At least 2251±524 km3 of sediment was removed from the formerly closed basin following the start of exorheism. This volume represents a mean basin-surface lowering of 65±13 m. Erosion estimates and landscape dissection patterns are consistent with geologic evidence of progressive establishment of an outward drainage system.Item Una década de investigación sobre el geopotencial(Investigación y ciencia, 2011) Catalán, Manuel; Muñoz Martín, AlfonsoItem Longest and still longer: The Messejana-Plasencia dyke and its links with later Alpine deformation belt in Iberia(Tectonophysics, 2021) De Vicente Muñoz, Gerardo; Olaiz Campos, Antonio José; Muñoz Martín, Alfonso; Cunha, Pedro P.The Messejana-Plasencia dyke (End-Triassic), NE-SW oriented, is the longest simple structure in Iberia (~500 km) and constitutes a first-order rheological discontinuity that crosses the entire crust. During the Alpine deformation, this discontinuity nucleated the Messejana-Plasencia left-lateral strike-slip fault and its related strike-slip deformation belt, consisting of a series of wide coalescent stepovers and small basins developed on the footwalls. Both structures can be followed from offshore of SW mainland Portugal to the central sector of the Spanish-Portuguese Central System. Using tectonic, geophysical, magnetic, and gravimetric analyses, our study demonstrated that it extends NE more than ~100 km below the continental sediments of the Duero Cenozoic Basin, until the Iberian Chain. We used a tectonostratigraphic analysis to determine the age of the wrench fault movement and that of the Spanish-Portuguese thrusts. In this range, the largest displacement during the Cenozoic occurred in the southern thrust of the Spanish sector of the Central System over the Madrid Cenozoic Basin, and NE-SW trending. This thrust displaces the Moho more than 10 km and probably joins the Messejana-lasencia strike-slip fault at depth. The deduced age movement for both is Oligocene-Lower-Middle Miocene, related to the intraplate stresses transmitted from the Pyrenean orogen towards its foreland. A strain partitioning process was then deduced for the simultaneous movement of both main Alpine faults in Central Iberia.Item Relationship between the fractal dimension anisotropy of the spatial faults distribution and the paleostress fields on a Variscan granitic massif (Central Spain): the F-parameter(Journal of Structural Geology, 2005) Pérez López, Raúl; Paredes, Carlos; Muñoz Martín, AlfonsoThe spatial distribution of faults is usually described as a fractal set characterised by the fractal dimension. In this work, we have filtered fault patterns interpreted from digital elevation models, aerial photographs and field maps, by using structural geological parameters of the stress ellipsoid (stress tensor direction and stress ratio R0) and age of deformation. From these filtered structural maps, we have obtained the fractal dimension associated with the fracture patterns developed during Permo-Triassic and Alpine tectonic events on a Variscan granitic massif located in the Spanish Central System. Oriented fractal dimensions were calculated on several transects crossing the fault-filtered maps. The fractal dimension (D), calculated by 1-D box-counting, describes an ellipse on a polar plot with the short axis as the minimum value (DHmin) and the long axis as the maximum value (DHmax) of the fractal dimensions measured. From these analyses, we have defined the F-parameter as a function of the maximum value, minimum value and vertical value of fractal dimension (Dz), FZ(DzKDHmin)/(DHmaxK DHmin). Finally we have established, from a local scale analysis, a perpendicular relationship between the principal axes of the ellipse of the fractal spatial anisotropy of fractures and the principal axes of the stress tensor (sHmax, sHmin and sz) that generates this dynamic pattern of fractures. Furthermore, the F-parameter and the stress ratio R0 are equivalents and, applied in this area, both show a triaxial extension.Item Erosión minera en la cuenca del arroyo Peñalén (Parque Natural del Alto Tajo, Guadalajara)(Comprendiendo el relieve: del pasado al futuro, 2016) Martín Moreno, Cristina; Martín Duque, José Francisco; Nicolau Ibarra, José Manuel; Muñoz Martín, AlfonsoItem Análisis de la estructura alpina de la corteza del centro de la Península Ibérica: Una sección Magneto-Telúrica a través del Sistema Central (Sierra de Gredos)(Geotemas, 2012) Pous, Jaume; Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Seillé, H.; De Vicente Muñoz, GerardoWe present a magnetotelluric profile across the Duero basin, the Central System and the Madrid basin, acquired in the framework of the TOPO-IBERIA project. The MT profile consists of 24 magnetotelluric sites over a 200 km, NS oriented profile. Five components were measured with periods ranging from 0.001 s to 500s. The dimensional analysis reveals a dominant E-W direction and 2D joint inversion of apparent resistivity, phases and tipper was carried out. The inverse resistivity model obtained has been compared with other geological and geophysical data, and it shows a resistive and homogeneous crust that extends towards the Duero basin. The main conductive anomalies are elongated and inclined bodies that are related with the main big–scale Alpine thrusts. Other superficial conductive bodies are related with the tertiary sedimentary basins. [RESUMEN]Este trabajo muestra un nuevo perfil magnetotelúrico (MT) a través del la cuenca del Duero, el Sistema central y la Cuenca de Madrid, adquirido dentro del proyecto TopoIberia. El Perfil MT consiste en 24 sondeos a lo largo de 200 km con una orientación NS. En cada sondeo se han medido cinco componentes con periodos de 0.001 a 500 s. El análisis dimensional revela una dirección dominante E-O y se ha realizado una inversión conjunta en 2D de las resistividades aparentes, fases y tipper. El modelo de resistividades obtenido ha sido comparado con otros datos geológicos y geofísicos, y muestra una estructura cortical homogénea y resistiva que se prolonga hacia la cuenca del Duero. En esta corteza aparecen cuerpos conductores inclinados y alargados en profundidad asociados a grandes cabalgamientos alpinos. Otros cuerpos conductores superficiales están claramente relacionados con las cuencas sedimentarias terciarias