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
5 results
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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 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 terciariasItem Análisis de la sensibilidad de las estimaciones de la profundidad del basamento en la cuenca de Madrid (España Central)(Geotemas, 2012) Olaiz Campos, Antonio José; Muñoz Martín, Alfonso; Gascone, L.; De Vicente Muñoz, Gerardo; Mantilla Pimiento, A.The Madrid basin, over 20.000 km2 , located in Central Spain. Its evolution is conditioned by basement uplifts (Central System and Toledo Mountains) during the Alpine orogeny. The Madrid basin is connected with the Loranca basin at its NE corner and with La Mancha basin to the south. Sediment thickness accumulated from Late Cretaceous to the Late Miocene, is about 3.000 m at Pradillo well, but from seismic interpretation, a depocenter associated to Central System South Thrust is inferred. For this study four different methodologies were used(“Euler Deconvolution”, “Source Parameter Imaging”, “Analytic Signal” and “Tilt Depth”), in order to obtain depth to basement estimations from aermagnetic data. These methods work for simplified source geometries, estimating depths as a good starting point for a structural interpretation. In Madrid Basin, this knowledge is important due to the geothermal and hydrological potential of the basin, as well as for CO2 storage. [RESUMEN]La cuenca de Madrid, con un área aproximada de 20.000 km2, se extiende en la zona central de la Península Ibérica. Su evolución está condicionada por el levantamiento del Sistema Central y de los Montes de Toledo durante la orogenia Alpina. La cuenca de Madrid está conectada con las cuencas de Loranca, en su límite NE, y de La Mancha por el sur. El espesor de sedimentos, con registro continuo desde el Cretácico Superior hasta el Mioceno Superior, alcanza los 3000 m en el pozo Pradillo, aunque de la interpretación sísmica se obtiene un depocentro, de mayor profundidad, adosado al cabalgamiento del Borde Sur del Sistema Central . En este trabajo se han seguido distintas metodologías para estimar la profundidad del basamento, a partir de datos aeromagnéticos. Los distintos métodos (“Deconvolucion de Euler”, “Source Parameter Imaging”, “Analytic Signal” y “Tilt Depth”) tienen en común que asumen geometrías sencillas, pero los resultados obtenidos resultan de gran interés para la interpretación estructural del basamento. En el caso de la cuenca de Madrid, este conocimiento es muy importante dado su potencial geotérmico e hidrogeológico, así como un posible uso como almacenamiento geológico.Item Spectral analysis of the gravity and elevation along the western Africa–Eurasia plate tectonic limit: Continental versus oceanic lithospheric folding signals(Tectonophysics, 2010) Muñoz Martín, Alfonso; De Vicente Muñoz, Gerardo; Fernández Lozano, Javier; Cloetingh, Sierd; Willingshofer, Ernst; Sokoutis, Dimitrios; Beekman, FredLarge-scale folding is a key mechanism of lithospheric deformation and has been described in many parts of the Earth, both for the continental and oceanic lithospheres. Some aspects of this process such as the presence of coupling/decoupling between the crustal deformation and the mantle lithosphere, or between different lithospheres, make it necessary to accurately control the periodic characteristics of the elevation and of the gravity signal. 1D spectral analysis of gravity and topography profiles is sensitive to a series of factors: the location, length and orientation of the profiles, as well as the number of samples taken. We carry out a systematic analysis of the periodicities in the topography and gravity, both 1D and 2D, along the western border of the Africa–Eurasia plate tectonic boundary. We analyze the sensitivity of the 1D and 2D spectral analysis in order to compare the results along a plate boundary where oceanic and continental lithospheres are in contact with different tectonic, kinematic and rheological aspects. Our 1D spectral results indicate that the greater the profile length, the longer the wavelength peaks that are found. Nevertheless there are some periodic signals that appear in almost all the analyzed profiles: 100–250 km for the N–S profiles across oceanic plate boundary and 150–250 km where the plate boundary is developed over continental lithospheres. The 2D spectral analysis avoids the problems found in relation to the particular location of the profile but the resulting wavelengths are slightly higher than those obtained from the 1D spectral analysis. The wavelengths estimated for both oceanic and continental lithospheres at the Africa–Eurasia boundary (N250 km) show low values of mean mantle strength (b1013 Pa m). he presence of lithospheric folds means that the continental and oceanic lithospheres are mechanically oupled. This had previously been suggested for Iberia but not for the limit between S Iberia and the Terceira riple Junction. The orientation of the lithospheric folds is NW–SE at the contact between continental lithospheres and NNE–SSW at the contact between oceanic lithospheres. This difference is also reflected in the signal anisotropy and must be related to the rotation of the tectonic stresses in the same direction. A large periodic signal (wavelength N600 km) was also detected both in 1D and 2D spectral results. After drawing the filtered values, the resulting maps indicate that this signal is related to the transition between continental and oceanic lithospheres and to the significant changes in crustal and/or lithospheric thickness from the Mid-Atlantic Ridge to the continental margins of western Eurasia.Item Mapa de esfuerzos activos en línea de la Península Ibérica a partir de Mecanismos Focales calculados desde el Tensor de Momento Sísmico(Geotemas, 2012) Muñoz Martín, Alfonso; De Vicente Muñoz, Gerardo; Olaiz Campos, Antonio José; Antón López, Loreto; Vegas Martínez, Ramón; Granja Bruña, José LuisThis work shows a new on-line stress map for Iberian Peninsula obtained from the inversion of earthquakes focal mechanisms calculated with the centroid moment tensor. An amount of 299 focal mechanisms have been selected with several quality criteria from different catalogues (CMT Harvard, ETH, Med-Net, I.G.N. and I.A.G.) from 1973 to January 2012. Values for the maximum horizontal stress and the shape factor of the ellipsoid (horizontal/vertical stress) have been calculated following De Vicente et al. (2008).. The local results have been interpolated to a 10’ regular grid in which the relation between tectonic horizontal stress and vertical load has been taken into account. The final map shows a good correlation with the primary tectonic forces generated in the plate boundaries and the local perturbations related with main crustal heterogeneities. Both the maps and data are free for download from http://www.ucm.es/info/lta/lta.html Applied Tectonophysics Group WebSite). [RESUMEN]Este trabajo muestra el nuevo mapa en línea de esfuerzos activos para la Península Ibérica obtenido a partir de la inversión de mecanismos focales de terremotos (MF) calculados con Tensor de Momento Sísmico (TMS). Un total de 299 MF han sido seleccionados con varios criterios de calidad de diferentes catálogos (CMT Harvard, ETH, Med-Net, I.G.N. e I.A.G.), para un periodo comprendido entre 1973 y enero de 2012 y profundidades menores de 60 km. Los valores de la dirección de máximo acortamiento horizontal (Dey) y el factor de forma (carga horizontal/vertical) han sido calculados siguiendo a De Vicente et al. (2008). Los resultados obtenidos se han interpolado a una malla regular de 10’, teniendo en cuenta las orientaciones de las componentes horizontales de esfuerzo, y el factor de forma. Los mapas finales muestran una buena correlación con indicadores geológicos y cinemáticos. Las orientaciones de los esfuerzos horizontales se relacionan con las fuerzas primarias provenientes de los límites de placas, y con perturbaciones locales relacionadas con heterogeneidades de primer orden a nivel cortical. Tanto los mapas, como los datos procesados son accesibles a través de la Web del Grupo de Tectonofísica Aplicada de la UCM http://www.ucm.es/info/lta/lta.html.