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
6 results
Search Results
Now showing 1 - 6 of 6
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 Magnetic anomalies of the NW Iberian continental margin and the adjacent abyssal plains(Journal of maps, 2020) Druet Vélez, María; Catalán, Manuel; Martín Dávila, José; Martos, J.M.; Muñoz Martín, Alfonso; Granja Bruña, José LuisThe NW Iberian margin is a hyperextended continental margin, formed during the opening of the North Atlantic Ocean, where a subsequent partial tectonic inversion has undergone during the Alpine Orogeny. This succession of tectonic episodes determines the magnetic signature of the margin. The Spanish Exclusive Economic Zone Project has carried out seven one-month cruises between 2001 and 2009. To extend and densify the spatial coverage, we have used data from the World Digital Magnetic Anomaly Map. Here, we describe the methodology used for the acquisition and data processing of the magnetic field data. The use of diverse instrumentation, a non-complete external field’s cancelation, and the use of different magnetic core field models, contributed to the total error budget. To reduce it, we have used a leveling algorithm which minimizes all these contributions. Finally, a statistical analysis was applied using crossover residuals, showing a resolution better than 28 nT.Item Integrated perspective of the present–day stress and strain regime in Colombia from analysis of earthquake focal mechanisms and geodetic data(The Geology of Colombia, 2020) Arcila, M.M.; Muñoz Martín, Alfonso; Gómez Tapias, Jorge; Pinilla-Pachón, Ana OlivaFocal mechanism analysis is a powerful tool for analyzing the geodynamic context of broad and complex regions, such as northwestern South America. In this zone, a complex tectonic convergence occurs among the Caribbean, Nazca, and South American Plates. The orientations of the maximum horizontal shortening and the values of the brittle strain/stress regime (k’ ratio) are obtained based on the analysis of 617 centroid–moment tensors reported from 1976 to 2017 in the Global Centroid–Moment–Tensor Project. These results are complemented with an analysis of GPS velocities, which can be used to determine the surficial deformation and to compare it with the crustal deformation to define the stress field in Colombia, and to formulate a seismotectonic model. This model is characterized by the slow southeastwards displacement of the Caribbean Plate, the convergence of the Andean, Coiba, and Panamá Blocks in northwestern Colombia, and the westwards convergence of the Nazca Plate below the South American overriding Plate. The strain/stress regime maps also show different tectonic environments and large–scale geological heterogeneities.Item Along-strike segmentation in the northern Caribbean plate boundary zone (Hispaniola sector): Tectonic implications(Tectonophysics, 2020) Rodríguez Zurrunero, Álvaro; Granja Bruña, José Luis; Muñoz Martín, Alfonso; Leroy, Sylvie; Ten Brink, Uri S.; Gorosabel-Araus, J.M.; Gómez de la Peña, Laura; Druet Vélez, María; Carbo Gorosabel, AndrésThe North American (NOAM) plate converges with the Caribbean (CARIB) plate at a rate of 20.0 ± 0.4 mm/yr. towards 254 ± 1º. Plate convergence is highly oblique (20-10º), resulting in a complex crustal boundary with along-strike segmentation, strain partitioning and microplate tectonics. We study the oblique convergence of the NOAM and CARIB plates between southeastern Cuba to northern Puerto Rico using new swath multibeam bathymetry data and 2D multi-channel seismic profiles. The combined interpretation of marine geophysical data with the seismicity and geodetic data from public databases allow us to perform a regional scale analysis of the shallower structure, the seismotectonics and the slab geometry along the plate boundary. Due to differential rollback between the NOAM oceanic crust north of Puerto Rico and the relative thicker Bahamas Carbonate Province crust north of Hispaniola a slab tear is created at 68.5ºW. The northern margin of Puerto Rico records the oblique high-dip subduction and rollback of the NOAM plate below the island arc. Those processes have resulted in a forearc transpressive tectonics (without strain partitioning), controlled by the Septentrional-Oriente Fault Zone (SOFZ) and the Bunce Fault Zone (BFZ). Meanwhile, in the northern margin of Hispaniola, the collision of the Bahamas Carbonate Province results in high plate coupling with strain partitioning: SOFZ and Northern Hispaniola Deformed Belt (NHDB). In the northern Haitian margin, compression is still relevant since seismicity are mostly associated with the deformation front, whereas strike slip earthquakes are hardly anecdotal. Although in Hispaniola intermediate-depth seismicity should disappear, diffuse intermediate-depth hypocenter remains evidencing the presence of remnant NOAM subducted slab below central and western Hispaniola. Results of this study improve our understanding of the active tectonics in the NE Caribbean that it is the base for future assessment studies on seismic and tsunamigenic hazard.- Project number: 196
Item Material audiovisual para el mural "El Tiempo en Geología" de la Facultad de Ciencias Geológicas(2020) García Lorenzo, María De La Luz; Arroyo Rey, Xabier; Soutullo García, Belén; Abati Gómez, Jacobo; Benito Moreno, María Isabel; Álvarez Sierra, María De Los Ángeles; Arribas Mocoroa, José; Arribas Mocoroa, María Eugenia; Castiñeiras García, Pedro; Crespo Feo, María Elena; Fernández Barrenechea, José María; García Romero, Emilia; Granja Bruña, José Luis; Iglesias Martínez, Mario; De Ignacio San José, Cristina; Martín Chivelet, Javier; Muñoz Martín, Alfonso; Orejana García, David; Ortega Menor, Lorena; Pieren Pidal, Agustín Pedro; Piña García, Rubén; Fernández Martín, Elena; Fernández Suffo, Paula; Muñoz Gallego, AlmudenaLa Geología abarca toda la historia del planeta, por lo que se hace inviable utilizar conceptos temporales de nuestra vida cotidiana. Por ello, se ha realizado un friso para el hall de la Facultad y para presentarlo, se ha realizado un vídeo explicativo del mismo. Item 3D Spatial Distribution of Arsenic in an Abandoned Mining Area: A Combined Geophysical and Geochemical Approach(Minerals, 2020) Ruiz Roso, Jesús; García Lorenzo, María De La Luz; Castiñeiras García, Pedro; Muñoz Martín, Alfonso; Crespo Feo, María ElenaAbandoned mine wastes, containing high sulfide contents, are of particular concern because of the formation of acid mine drainage (AMD), becoming an active and harmful point source of potentially toxic elements (PTEs) to the environment. A detailed evaluation of the chemical and mineralogical composition of mining wastes is necessary to determine effective remediation actions. Due to the high amount of generated wastes as a result of mining and processing activities, the cost and time consumed for this characterization are limiting. Hence, efficient tools could be applied to predict the composition of these wastes and their spatial distribution. This study aims to determine the physico-chemical characterization of wastes from mining activities using geochemical and geophysical techniques. The obtained results, both geochemical and geophysical, allow us to locate areas with a high potential risk of contamination by As in an economic and simple way, and enable us to design detailed geochemical sampling campaigns. In addition, the fact that there are conductive fractures in depth suggests the possible circulation of contaminants through them as well as the preferential lines of circulation.