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
72 results
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Now showing 1 - 10 of 72
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 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 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 terciariasItem Exceptional river gorge formation from unexceptional floods(Nature Communications, 2015) Antón López, Loreto; Mather, A.E.; Stokes, M.; Muñoz Martín, AlfonsoAn understanding of rates and mechanisms of incision and knickpoint retreat in bedrock rivers is fundamental to perceptions of landscape response to external drivers, yet only sparse field data are available. Here we present eye witness accounts and quantitative surveys of rapid, amphitheatre-headed gorge formation in unweathered granite from the overtopping of a rock-cut dam spillway by small-moderate floods (B100–1,500m3 s�1). The amount of erosion demonstrates no relationship with flood magnitude or bedload availability. Instead, structural pattern of the bedrock through faults and joints appears to be the primary control on landscape change. These discontinuities facilitate rapid erosion (4270m headward retreat; B100m incision; and B160m widening over 6 years) principally through fluvial plucking and block topple. The example demonstrates the potential for extremely rapid transient bedrock erosion even when rocks are mechanically strong and flood discharges are moderate. These observations are relevant to perceived models of gorge formation and knickpoint retreat.Item 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 Análisis de los esfuerzos tectónicos de la crisis sísmica de 2010 en Haití(Geogaceta, 2014) López Cuesta, Víctor; Muñoz Martín, Alfonso; Granja Bruña, José LuisEl evento de Mw=7 del 12 de enero 2010 provocó una crisis sísmica en el sur de Haití, que duró 3 meses. Se ha realizado un análisis de inversión de esfuerzos de los mecanismos focales del evento principal y 50 réplicas. El evento principal fue generado por un falla de buzamiento 64ºN y dirección N084Eº con una componente principal de deslizamiento lateral-izquierda y una componente inversa. Las réplicas se han generado por fallas inversas puras ENE-OSO situadas en la zona de interacción entre estructuras compresivas orientadas NO-SE y de desgarre orientadas E-O. Estas réplicas han sido activadas por un régimen de esfuerzos compresivo uniaxial muy homogéneo orientado con σ1 horizontal según N017ºE ±10º. La ausencia de ruptura en superficie indica que el origen de las réplicas son fallas ciegas orientadas N097º-117ºE. Los datos de deformación superficial intersísmica obtenidos a partir de velocidades derivadas de GPS para la zona epicentral muestran una desviación angular de ≈30º respecto a la orientación de σ1 obtenidos del análisis de esfuerzos. Esta desviación sugiere que una parte significativa de la energía elástica acumulada a lo largo de las estructuras de tendencia E-O no fue liberada durante la crisis sísmica de 2010.Item Present-Day Crustal Stress Field from Gcmt Focal Mechanisms Based on the Slip Model.(Conference Proceedings, 83rd EAGE Annual Conference & Exhibition, 2022) Olaiz Campos, J. A.; Muñoz Martín, Alfonso; De Vicente Muñoz, GerardoThe Slip Model is applied to the Global Centroid Moment Tensor database to determine the present day state of stress. Thus, from each focal mechanism the horizontal shortening direction (Dey) and the shape factor of the strain ellipsoid (k`), defined as the relationship between the maximum horizontal shortening and the vertical axis, are calculated. Additionally, this method proposed the neoformed plane from the calculated nodal planes. In this study, to determine the stress configuration at crustal scale, only depths < 40 km are included. Focal mechanisms are grouped in reverse, strike-slip and normal, to analyse its distribution and to determine the b-parameter from Gutenberg-Richter law. Finally, global shape factor and horizontal shortening direction maps are presented.