Person:
Muñoz Martín, Alfonso

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First Name
Alfonso
Last Name
Muñoz Martín
URI
https://hdl.handle.net/20.500.14352/75220
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Geodinámica, Estratigrafía y Paleontología
Area
Geodinámica Interna
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Author: Olaiz Campos, Antonio José × Start date: 2003 × Item Type: Publication × Subject: 551.24 ×

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Now showing 1 - 3 of 3
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    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.
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    El cabalgamiento de Valdesotos: consecuencias de la acomodación del acortamiento cenozoico en el zócalo del Sistema Central
    (Geotemas, 2004) Olaiz Campos, Antonio José; Vicente Muñoz, Gerardo de; Vegas, Ramón; González Casado, José Manuel; Muñoz Martín, Alfonso; Álvarez, J.
    We describe and study structural evidences concerning to Alpine tectonics at NE sector o f the Spanish Central System (SCS). In Valdesotos area, the Hercynian basement is uplifted over Mesozoic sediments, throughout a main SW verging thrust. Fault population analysis and geological mapping has been used to look at the relation between structures in the basement and in the cover. As a consequence of accommodation of strains in the basement, kink folds are developed, such as secondary thrust and folds in the tegument. All these meso- and macrostructures seem to answer to a shortening in agreement with the Cenozoic deformation.
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    Near surface geophysical analysis of the Navamuño depression (Sierra de Béjar, Iberian Central System): Geometry, sedimentary infill and genetic implications of tectonic and glacial footprint
    (Geomorphology, 2018) Carrasco González, Rosa María; Turu, Valenti; Pedraza Gilsanz, Javier de; Muñoz Martín, Alfonso; Ros, Xavier; Sánchez Vizcaíno, Jesús; Ruiz Zapata, Blanca; Olaiz Campos, Antonio José; Herrero-Simon, Ramón
    The geometric and genetic characterization of the Navamuño depression peatland system (Iberian Central System) is presented here using results from a geophysical survey. This depression is a ~30 ha pseudo-endorheic flat basin over granitic bedrock. Three geophysical techniques were used to map the subsurface geology, and identify and describe the infill sequence: shallow seismic refraction (SR), magnetic resonance sounding (MRS) and electrical resistivity measurements (VES and ERT). The three main geoelectrical layers (G1, G2, G3) identified in previous research, have also been identified in the present work. Using the data obtained in this new research we have been able to analyse these three geological layers in detail and reinterpret them. They can be grouped genetically into two sedimentary units: an ancient sedimentary body (G3), of unknown age and type, beneath an Upper Pleistocene (G2) and Holocene (G1) sedimentary infill. The facies distribution and geometry of the Upper Pleistocene was examined using the Sequence Stratigraphy method, revealing that the Navamuño depression was an ice-dammed in the last glacial cycle resulting in glaciolacustrine sedimentation. A highly permeable sedimentary layer or regolith exists beneath the glaciolacustrine deposits. Below 40 m depth, water content falls dramatically down to a depth of 80 m where unweathered bedrock may be present. The information obtained from geophysical, geological and geomorphological studies carried out in this research, enabled us to consider various hypotheses as to the origin of this depression. According to these data, the Navamuño depression may be explained as the result of a transtensional process from the Puerto de Navamuño strike-slip fault during the reactivation of the Iberian Central System (Paleogene-Lower Miocene, Alpine orogeny), and can be correlated with the pull-apart type basins described in these areas. The neotectonic activity of this fault and the icedammed processes in these areas during the Last Glacial Cycle (MIS2) were the main causes of recent sedimentary infill in this depression.