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
13 results
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Now showing 1 - 10 of 13
Item Morphostructure at the junction between the Beata ridge and the Greater Antilles island arc (offshore Hispaniola southern slope)(Tectonophysics, 2014) Granja Bruña, José Luis; Carbó Gorosabel, Andrés; Llanes Estrada, Pilar; Muñoz Martín, AlfonsoOblique convergence between the Caribbean plate's interior and the inactive Greater Antilles island arc has resultedin the collision and impingement of the thickened crust of theBeata ridge into southern Hispaniola Island. Deformation resulting from this convergence changes from a low-angle southward-verging thrust south of easternHispaniola, to collision and uplift in south-central Hispaniola, and to left-lateral transpression along theSouthern peninsula of Haiti in western Hispaniola. Using new swath bathymetry and a dense seismic reflectiongrid, we mapped the morphological, structural and sedimentological Elements of offshore southern Hispaniola.We have identified four morphotectonic provinces: the Dominican sub-basin, the Muertos margin, the Beataridge and the Haiti sub-basin. The lower slope of the Muertos margin is occupied by the active Muertos thrustbelt, which includes several active out-of-sequence thrust faults that, were they to rupture along their entirelength, could generate large-magnitude earthquakes. The interaction of the thrust beltwith the Beata ridge yieldsa huge recess and the imbricate system disappears. The upper slope of the Muertos margin shows hick slopedepositswhere the extensional tectonics and slumping processes predominate. The northern Beata ridge consistsof an asymmetrically uplifted and faulted block of oceanic crust. Our results suggest that the shallower structureand morphology of the northern Beata ridge can be mainly explained by a mechanism of extensional unloadingfrom the Upper Cretaceous onward that is still active residually along the summit of the ridge. The tectonicmodels for the northern Beata ridge involving active reverse strike–slip faults and transpression caused by theoblique convergence between the Beata ridge and the island arc are not supported by the structural interpretation.The eastern Bahoruco slope an old normal fault that acts as a passive tear fault accommodating the sharpalong-strike transition from low-angle thrusting to collision and uplifting.Item Nueva interpretación del relleno sedimentario de la Cuenca de San Pedro (Offshore de la República Dominicana) en base a nuevos datos sísmicos(Geotemas, 2016) Gorosabel Araus, J.M.; Granja Bruña, José Luis; Carbó Gorosabel, Andrés; Gómez de la Peña, Laura; Rodríguez Zurrunero, Álvaro; Muñoz Martín, Alfonso; Pazos, Antonio; Gómez Ballesteros, María; Druet Vélez, María; Llanes Estrada, PilarLos nuevos datos de sísmica de reflexión multicanal 2D adquiridos en la Cuenca de San Pedro (margen sudeste de la República Dominicana), junto con antiguos perfiles sísmicos reprocesados, han permitido llevar a cabo un detallado análisis y revisión de la estratigrafía sísmica. Los nuevos datos sísmicos aportan nuevas precisiones sobre la evolución de la cuenca sugiriendo un origen de al menos Eoceno Superior, en lugar de Mioceno. La nueva interpretación se basa en la correlación onshore-offshore de un nivel guía de abanicos bien desarrollado, con los eventos tectónicos constreñidos tierra y asociados a la colisión con los Bancos de las Bahamas con el arco isla el Eoceno Medio.Item Cartografía de dominios litosféricos y estilo de deformación en el margen continental de Galicia (margen noroeste de la Península Ibérica)(Geotemas, 2016) Druet Vélez, María; Muñoz Martín, Alfonso; Granja Bruña, José Luis; Carbó Gorosabel, Andrés; Acosta, Juan; Llanes Estrada, Pilar; Ercilla, GemmaEl margen continental de Galicia presenta una estructura muy compleja, debido a dos efectos principales. Por un lado, se trata de un margen de rift pobre en magma, generado en las proximidades del punto triple R-R-R que dio lugar a la apertura simultánea del Océano Atlántico y el golfo de Vizcaya durante el Cretácico. Por otra parte, el régimen de esfuerzos compresivo Cenozoico generó la inversión parcial del margen continental hacia el norte y el noroeste, aportando una mayor complejidad estructural. En este trabajo hemos realizado un análisis detallado de la nueva información gravimétrica y batimétrica obtenida durante las campañas del Proyecto ZEE, así como de nuevos perfiles de sísmica de reflexión multicanal procedentes del Proyecto ERGAP. Presentamos aquí parte de los resultados de este análisis conjunto de toda la información geofísica y geológica disponible, consistentes en una cartografía continua de los diferentes dominios litosféricos y del tipo de deformación que los afectan, desde el margen oeste de la Península Ibérica hasta el margen norte.Item Crustal structure and continent?ocean boundary along the Galicia continental margin (NW Iberia): insights from combined gravity and seismic interpretation(Tectonics, 2018) Druet Vélez, María; Muñoz Martín, Alfonso; Granja Bruña, José Luis; Carbó Gorosabel, Andrés; Acosta, Juan; Llanes Estrada, Pilar; Ercilla, GemmaThe magma?poor rifted continental margin of Galicia has an extremely complex structure. Its formation involved several rifting episodes that occurred ultimately during the early Cretaceous near a ridge triple junction, which produced a change in the orientation of the main structures in its transition to the north Iberia margin. In addition, there is a superimposed partial tectonic inversion along its northwest and northern border which developed from the Late Cretaceous to at least Oligocene times. The present study integrates a large volume of new geophysical information (mainly marine gravity data and 2D seismic reflection profiles) to provide insights on the formation of this rift system and on the development of its later inversion. The combined interpretation and modeling of this data enable the presentation of a new crustal and structural domains map for the whole Galicia margin. This includes the rift domains related to the extreme thinning of the crust and the lithospheric mantle (stretched, necking, and hyperextension and mantle exhumation (HME) domains), as well as a domain of intense compressional deformation. New constraints arise on the origin, the deep structure, and the characterization of the along? and across?strike variation of the continent?ocean transition of the margin, where a progressive change from hyperextension to partial inversion is observed. The development of both rifting and later partial tectonic inversion is influenced by the existence of former first?order tectonic features. Most of the tectonic inversion is focused on the HME domain, which in some areas of the northwestern margin is completely overprinted by compressional deformation.Item Modelización gravimétrica de la transición entre corteza continental y oceánica en el margen oeste de Galicia(Geotemas, 2004) Druet Vélez, María; Muñoz Martín, Alfonso; Carbó Gorosabel, Andrés; Álvarez García, Juan; Llanes Estrada, PilarSince 2001 marine gravity data have been collected on the North Atlantic Ocean around Galicia Mar,-,in. The aim of this paper is the analysis of the Bouguer anomaly map of the west margin of Galicia and the modelling of the ocean-continent boundary in this area. Very high Bouguer anomaly values have been obtained for this region, specially in the oceanic trust of the Iberian Abyssal Plain. A gravity low is related to the Galicia Bank continental block, and relative positive elongate highs correspond with the Peridotite Ridge and the Galicia Interior Basin. The two gravity models presented here, based on seismic refraction and reflection profiles, have allowed the characterization of the gravity limit between oceanic and continental trust in this margin. This limit is located 15 km eastwards in the northern profile 1, from the previous proposed limit based on sedimentary criteria.Item Gravity modeling of the Muertos Trough and tectonic implications (north-eastern Caribbean)(Marine Geophysical researches, 2010) Granja Bruña, José Luis; Muñoz Martín, Alfonso; Ten Brink, Uri S.; Carbó Gorosabel, Andrés; Llanes Estrada, Pilar; Martín Dávila, José; Córdoba Barba, Diego; Catalán, ManuelThe Muertos Trough in the northeast Caribbean has been interpreted as a subduction zone from seismicity, leading to infer a possible reversal subduction polarity. However, the distribution of the seismicity is very diffuse and makes definition of the plate geometry difficult. In addition, the compressive deformational features observed in the upper crust and sandbox kinematic modeling do not necessarily suggest a subduction process. We tested the hypothesized subduction of the Caribbean plate’s interior beneath the eastern Greater Antilles island arc using gravity modeling. Gravity models simulating a subduction process yield a regional mass deficit beneath the island arc independently of the geometry and depth of the subducted slab used in the models. This mass deficit results from sinking of the less dense Caribbean slab beneath the lithospheric mantle replacing denser mantle materials and suggests that there is not a subducted Caribbean plateau beneath the island arc. The geologically more realistic gravity model which would explain the N–S shortening observed in the upper crust requires an overthrusted Caribbean slab extending at least 60 km northward from the deformation front, a progressive increase in the thrusting angle from 8 to 30 reaching a maximum depth of 22 km beneath the insular slope. This new tectonic model for the Muertos Margin, defined as a retroarc thrusting, will help to assess the seismic and tsunami hazard in the region. The use of gravity modeling has provided targets for future wide-angle seismic surveys in the Muertos Margin.Item El terremoto de Haití(Enseñanza de las ciencias de la tierra, 2011) Granja Bruña, José Luis; Carbó Gorosabel, Andrés; Hernáiz-Huerta, Pedro Pablo; Llanes Estrada, Pilar; Muñoz Martín, Alfonso; Olaiz Campos, Antonio JoséItem Morphological and structural analysis in the Anaga offshore massif, Canary Islands: fractures and debris avalanches relationships(Marine Geophysical Researches, 2003) Llanes Estrada, Pilar; Muñoz, Araceli; Muñoz Martín, Alfonso; Acosta, Juan; Herranz Araújo, Pedro; Carbó Gorosabel, Andrés; Palomo, CarlosAs part of the ‘National Hydrographic and Oceanographic Research Plan for the Spanish Exclusive Economic Zone’, multibeam bathymetry and seismic reflection profiles were obtained in the Canary Islands aboard the R/V Hespérides. The submarine flanks of the Anaga offshore extension of Tenerife Island are here studied to analyze its geomorphology. In the north sector of the Anaga submarine massif, the extension of the Anaga Debris Avalanche has been mapped for the first time, and a volume of 36 km3 was calculated. The relationship between the Anaga and Orotava Debris Avalanches is also described. Faulting has been recognized as a key process for the occurrence of debris avalanches and the growth of volcanic lineaments. Moreover, faulting affects previous structures and the channelling of debris flows. Structural analysis shows the typical radial pattern of an oceanic island. In addition, a NE-SW dominant direction of faulting was obtained, consistent with the Tenerife Island structural trend seen in the Anaga Massif and Cordillera Dorsal. NW-SE and E-W are two other main trends seen in the area. Special interest is manifest in two long faults: ‘Santa Cruz Fault’ bounds the southern edge of Anaga offshore Massif with a length of 50 km and a direction that changes from NE-SW to almost E-W. The Güimar Debris Avalanche was probably channeled by this fault. The ‘Guayotá Fault’ was recognized in several seismic profiles with a N-S direction that changes towards NW-SE at its southern end. This fault affects the more recent sediments with a vertical offset of 25–30 m, along 60 km. It has been interpreted as a transpressive strike-slip fault.Item Shallower structure and geomorphology of the southern Puerto Rico offshore margin(Marine and Petroleum Geology, 2015) Granja Bruña, José Luis; Ten Brink, Uri S.; Muñoz Martín, Alfonso; Carbó Gorosabel, Andrés; Llanes Estrada, PilarOblique convergence between the North American and Caribbean plates along the eastern Greater Antilles island arc has yielded the asymmetric Muertos thrust belt in the backarc region. Offshore south of Puerto Rico, this thrust belt disappears and is replaced by a succession of NEeSW- and EeW-trending deep basins and steep ridges that characterize the western Anegada passage, resulting in a complex deformation pattern. Using new high-resolution multibeam bathymetry and seismic reflection profiles, we studied the geomorphology and shallower structure of the southern Puerto Rico offshore margin. We have identified four morphotectonic provinces: the Puerto Rican sub-basin and Muertos trough, the Muertos margin, the insular shelf and the western Anegada passage. The Muertos margin province shows two distinct slope sub-provinces: the active Muertos thrust belt e which includes lower and upper thrust belts with distinct deformational styles and lateral continuity e and the shelf slope highly-incised by a dense canyon network. This network is disrupted by the Investigator fault zone consisting of a 130 km-long EeW-trending band of active extensional deformation. The Investigator fault zone shows differential surface expression caused by along-strike changes in the magnitude and distribution of the deformation, though this deformation is driven by a NeS-oriented extension. In the western Anegada passage province, the Whiting basin and Whiting and Grappler ridges are formed by large dip-slip normal faults driven by a NWeSE-oriented extensional regime. The western St. Croix rise shows a complex structure where the NEeSW-trending NW-dipping normal faults observed at the summit of the rise predate the EeW-bounding faults that could accommodate the extensional deformation at the Present. This study provides detailed observations on the active tectonic and sedimentary processes to help future studies assessing the natural resources and the seismic and tsunamigenic hazard in the Puerto Rico region.Item Exploring active tectonics in the Dominican Republic(Eos, Transactions American Geophysical Union, 2010) Carbó Gorosabel, Andrés; Córdoba Barba, Diego; Martín Dávila, José; Granja Bruña, José Luis; Llanes Estrada, Pilar; Muñoz Martín, Alfonso; Ten Brink, Uri S.One recent project, Caribbean–North American Plate Boundary Analysis: From Beata Ridge (Dominican Republic) to Anegada Passage (Lesser Antilles) (CARIBENORTE), has conducted onshore and offshore surveys in the Dominican Republic region to study subduction, strike- slip, and collision processes in this area. This survey included a cruise aboard the Spanish R/V Hespérides in April 2009 and simultaneous fieldwork onshore. The CARIBE NORTE project complements the study of the northeastern Caribbean plate boundary carried out during the Structure and Geodynamics of the Northeastern Boundary of the Caribbean Plate: Puerto Rico (GEOPRICO- DO) project in 2005 [Carbó et al., 2005].