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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Now showing 1 - 5 of 5
Item Controles tectónicos y estructurales de la incisión fluvial en el centro-oeste de la Cuenca del Duero, NO de Iberia(Geogaceta, 2007) Antón López, Loreto; Muñoz Martín, AlfonsoThe present work approaches incision rates quantification of Duero River in the central- west par t of Iberia and implications of tectonics in the evolution and change of drainage patterns. For this aim we calculate incision rates from the two main geomorphological surfaces defined in the area. Comparing fluvial incision rates and fracture pattern a strong structural control is shown; either in the orientation of drainage network, either in the incision rates distribution. Drainage pattern shows two main orientations, NW-SE following the hercinian structure of the area and NE-SW to N-S matching with the main fracture sets (Duero, Almendra, Almeida-Valderaduey faults, as example). Fluvial incision is mostly controlled by the great faults and faults systems NE-SW to N-S oriented.Item Análisis de la geometría en profundidad de fracturas conductoras en zonas de baja permeabilidad mediante tomografía eléctrica (El Berrocal, Sistema Central Español)(Geogaceta, 2007) Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Vicente Muñoz, Gerardo de; Antón López, Loreto; Elorza, Francisco José; Vicente, Raquel deThe groundwater flow in zones of low permeability, as granites, is mainly associated with zones of fracture. For this reason the characterization of the fractures is fundamental, both in surface as in depth, and must integrate geological information (geological mapping, structural analysis), geophysics (mainly electrical and electromagnetic methods) and geochemistry (radon and others gases) with hydrogeology. In this work we analyze the geophysical response of a strike-slip fault zone by means of three 2D resistivity models. The objective is to investigate the presence of several conductive zones and their geometry in depth. The obtained results allow to control the geometry in depth of the fractures, the gaps between the different mapped traces along the fault zone as well as the thickness of landfill. All this information will be useful for the hidromechanical simulation of the massif, and to check the geometry and gas permeability calculated from emanometry.Item Aplicación del método electromagnético de inducción ligera para el análisis de la permeabilidad en medios fracturados (granito de “El Berrocal”, Sistema Central Español)(Geogaceta, 2009) Vicente, Raquel de; Muñoz Martín, Alfonso; Olaiz Campos, Antonio José; Antón López, Loreto; Vicente Muñoz, Gerardo deFracture characterization in granites has been an important subject of study during these last years, by means of geological-structural cartography, hydrogeology and geochemical analysis. All these works have been carried out to investigate the hydromechanics and permeability in low-permeability rocks. In this study we apply a surface geophysical method in order to characterize the permeability of the fault zones affecting “El Berrocal” granite (Central System, Spain). The low-induction electromagnetic method (EM) gives us the apparent resistivity values of the rocks at a maximum depth, allowing us to differentiate between soil / altered rock from fresh granites. As the apparent resistivity depends on the granite alteration and/or the water content, this parameter allows to estimate the relative permeability of different fracture zones. The obtained results show that the high-permeability fractures are those that are larger ones which were active during Alpine deformation (Eocene-present).Item Análisis de la fracturación y campos de paleoesfuerzos en el centrooeste de la Península Ibérica.(Geotemas, 2004) Antón López, Loreto; Muñoz Martín, Alfonso; Vicente Muñoz, Gerardo deThe Tormes Dome is a granitic massif emplaced during the Hercinian orogeny and later deformed by several posthercynian fracturation episodes. Three main paleostress fields have been obtained from stress inversion o f 1375 fault-slip data collected throughout the study area. The maximum horizontal stress (SHMAX) are oriented N-S, NE-SW and E-W with extensional and strike-slip stress regimes. Difficulties to determine age dating o f the three paleostress fields made necessary to enlarge the study area to the surrounding Cenozoic basins borders. In addition, geocronological information obtained form K-Ar dating o f fault gouges collected in the Tomes Dome has been used to establish the relative chronology of the three tectonic episodes from field data and determine their activity periods form Mesozoic to present time. An important result is that there is no relevant brittle tectonic activity associated with the recent NW-SE stress field in the western peninsula from Upper Miocene to the present times and some field evidences, as well as two focal mechanisms of earthquakes occurred in the area seem that in the Tormes Dome the recent stress field present an Shmax oriented N-S.Item Datación de eventos tectónicos mediante integración de geocronología K-Ar y análisis de paleoesfuerzos en el Domo del Tormes(Geotemas, 2004) Antón López, Loreto; Muñoz Martín, Alfonso; Vicente Muñoz, Gerardo de; Galindo Francisco, Mª del CarmenThe present paper deals with K-Ar absolute dating performed on three fault gouges structures selected across the geological structure known as the Domo del Tormes (Zamora-Salamanca, Spain). The dating performed on five clay samples, with grain size of 0,2-0,4mm and <0,2mm, provides ages from 210 ± 11 to 86,9 ± 4,3 Ma. The interpretation of the results obtained by both geocronological and fault population analysis methods contributed relevant data to ascertain the age of the various palaeostress fields defined in the study area, with maximum horizontal compression oriented E-W and NE-SW.