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
4 results
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Item 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 Variscan inheritance induces Alpine upper crustal delamination in East Spanish–Portuguese Central System(Tectonics, 2022) De Vicente Muñoz, Gerardo; Díez Fernández, Rubén; Olaiz Campos, Antonio José; Muñoz Martín, AlfonsoThe Spanish–Portuguese Central System (SPCS) is an Alpine Mountain range with crystalline basement characterised by a two-layer rheological structure. This structure formed after primary (protolith) and secondary (tectonometamorphic) processes during the extensional collapse of the Variscan Orogen. The SPCS structure is usually controlled by foreland-directed thrusts and strike-slip faults. However, the eastern SPCS is dominated by NW-directed, imbricate backthrusts and lacks the main thrust directed to the foreland basin located southeast of the mountain range (Madrid Cenozoic Basin). The SPCS exhibits a crustal root (> 40 km depth) supporting SE-directed crustal-scale thrusting. Alpine backthrusts sole into an SE-dipping décollement within the Variscan basement. Variscan extension-related structures parallel the SE-dipping geometry of Alpine backthrusts, so they provided favourably oriented rheological weaknesses to accommodate Alpine shortening. Backthrusts geometry, their hanging wall position within the fault that raised the SPCS and gravity modelling support an Alpine crustal delamination process. Tectonic wedging and delamination of the more competent basement occurred in the footwall of Variscan extensional faults (Daurius domain), which enforced the shearing off of a rheologically weaker upper layer of the crust, located in the hanging wall of the Variscan extensional faults (Arriaca domain) by inverting Variscan extensional faults. This led to NW-directed incipient continental subduction of the weaker crust. Intraplate subduction and crustal delamination can be independent from lithosphere-scale inheritance and be conditioned by structural inheritance in the overlying crust. Alpine shortening for the Cretaceous cover is around 17.7 km (10.5% shortening), and 11 km (7%) for the upper-lower crust limit.Item Geometría y modelado numérico de los cabalgamientos Alpinos y de los pliegues de propagación de falla asociados en el macizo de Honrubia-Sepúlveda (Sistema Central)(Geotemas, 2024) Muñoz Cemillán, Alfonso; Muñoz Martín, Alfonso; Vicente Muñoz, Gerardo De; Olaiz Campos, Antonio JoséEl sector de Honrubia-Sepúlveda (Norte del Sistema Central) se caracteriza por presentar una serie de cabalgamientos imbricados con basamento implicado y vergencia hacia el norte. Estos cabalgamientos desarrollan pliegues de propagación de falla en la cobertera mesozoica con flancos largos de bajo buzamiento hacia el sur (entre 2 y 5º). Dada la ausencia de datos en profundidad, y debido a su estilo “de piel fina con basamento implicado”, algunos autores interpretan la presencia de un nivel de despegue relativamente somero en profundidad. Para discutir esta estructura se han analizado y modelizado con el método de trishear uno de estos pliegues que presentan mejor desarrollo (Allmendinger, 1998). Los resultados de la modelización sugieren desechar la presencia de geometrías rampa-rellano, y la ausencia de un nivel de despegue común superficial para los cabalgamientos. Los resultados obtenidos también descartan otras geometrías de la rampa, como son las de un aumento del buzamiento de los cabalgamientos en profundidad, o rampas con geometrías lístricas. Los modelos que mejor explican la geometría del pliegue de propagación se generan mediante fallas inversas de buzamiento constante (entre 40 y 50º), valores de p/s entre 1.5 y 1.8 y ángulos de trishear estrechos (de unos 60º).Item Geothermal Potential of Madrid Basin from Integrated Geophysical and Well Data Analysis (Central Spain)(Conference Proceedings, 83rd EAGE Annual Conference & Exhibition, 2022) Berriolópez, M.A.; Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Zamora Valcarce, GonzaloNew energy demand linked to world population growth and awareness about climate change have brought out the need to develop new forms of energy guided by the urgency of an ecological transition. In this context geothermal resources have the potential of contributing significantly to sustainable use in many parts of the world. In Spain, during the 80´s, oil and gas explorations carried out in the Madrid Basin confirmed the existence of two geothermal reservoirs. Here we present diverse geological features of the basin essential in geothermal exploration. We use airborne radiogenic and magnetic data to characterize the basement. Detailed ground concentration estimates of the heat producing elements are used to calculate the heat production and heat flow in the near surface. The distribution pattern of both parameters is heterogeneous with two main areas separated by southward prolongation of the Berzosa Fault. The eastern sector is characterized by both low heat production and heat flow rates while the western area is distinguished by high values as a response of the exposed granites. In addition, we build one 3D geological model and one 3D isothermal model with Leapfrog Geothermal from seismic, well data and mapping information.