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 Late glacial and post-glacial deposits of the Navamuño peatbog (Iberian Central System): Chronology and paleoenvironmental implications(Quaternary International, 2018) Turu, Valenti; Carrasco González, Rosa María; Pedraza Gilsanz, Javier de; Ros, Xavier; Ruiz-Zapata, María Blanca; Soriano-López, Joan Manuel; Mur-Cacuho, Elena; Pélachs-Mañosa, Albert; Muñoz Martín, Alfonso; Sánchez, Jesús; Echeverria-Moreno, AnnaThe Navamuño peatbog (Sierra de Béjar, western Spain) is a ∼14 ha pseudo-endorheic depression with boundaries defined by a lateral moraine of the Cuerpo de Hombre paleoglacier and fault-line scarps on granite bedrock. The stratigraphy of the Navamuño peatbog system is characterized here using borehole data to a depth of 20 m. An integrated interpretation from direct-push coring, dynamic probing boreholes and handheld auger drillings advances our knowledge of the Navamuño polygenetic infill. Correlating this data with those obtained in other studies of the chronology and evolutionary sequence of the Cuerpo de Hombre paleoglacier has enabled us to establish the sequence of the hydrological system in the Navamuño depression. During the Late Pleistocene (MIS2), the depression was dammed by the Cuerpo de Hombre glacier and fed by its lateral meltwaters, and was filled with glaciolacustrine deposits. The onset of the Holocene in Navamuño is linked to a flat, fluviotorrential plain with episodes of local shallow pond/peat bog sedimentation. This evolutionary sequence is congruent with the age model obtained from available radiocarbon dating, obtaining 19 ages from ∼800 cal yr BP (at depth 1.11 m) to ∼16800 cal yr BP (at depth 15.90–16.0 m). Finally, the sedimentary record enabled interpretation of the environmental changes occurring in this zone during the late glacial (from the Older Dryas to the Younger Dryas) and postglacial (Holocene) stages, placing them within the paleoclimatic context of the Iberian Peninsula and Mediterranean regions.Item Late glacial and post-glacial deposits of the Navamuno peatbog (Iberian Central System): Chronology and paleoenvironmental implications(Quaternary International, 2017) Turu, Valenti; Carrasco González, Rosa María; Pedraza Gilsanz, Javier de; Ros, Xavier; Ruiz-Zapata, Blanca; Soriano-López, J.M.; Mur-Cacuho, E.; Pélachs-Mañosa, A.; Muñoz Martín, Alfonso; Sánchez, J.; Echeverria-Moreno, A.The Navamuno peatbog (Sierra de Bejar, western Spain) is a ~14 ha pseudo-endorheic depression with boundaries defined by a lateral moraine of the Cuerpo de Hombre paleoglacier and fault-line scarps on granite bedrock. The stratigraphy of the Navamu~no peatbog system is characterized here using borehole data to a depth of 20 m. An integrated interpretation from direct-push coring, dynamic probing boreholes and handheld auger drillings advances our knowledge of the Navamu~no polygenetic infill. Correlating this data with those obtained in other studies of the chronology and evolutionary sequence of the Cuerpo de Hombre paleoglacier has enabled us to establish the sequence of the hydrological system in the Navamuno depression. During the Late Pleistocene (MIS2), the depression was dammed by the Cuerpo de Hombre glacier and fed by its lateral meltwaters, and was filled with glaciolacustrine deposits. The onset of the Holocene in Navamuno is linked to a flat, fluviotorrential plain with episodes of local shallow pond/peat bog sedimentation. This evolutionary sequence is congruent with the age model obtained from available radiocarbon dating, obtaining 19 ages from ~800 cal yr BP (at depth 1.11 m) to ~16800 cal yr BP (at depth 15.90e16.0 m). Finally, the sedimentary record enabled interpretation of the environmental changes occurring in this zone during the late glacial (from the Older Dryas to the Younger Dryas) and postglacial (Holocene) stages, placing them within the paleoclimatic context of the Iberian Peninsula and Mediterranean regions.Item Caracterización de la geometría de la depresión de Navamuño (Sistema Central Español) aplicando técnicas geofísicas(Geogaceta, 2015) Carrasco González, Rosa María; Sánchez, Jesús; Muñoz Martín, Alfonso; De Pedraza, Javier; Olaiz Campos, Antonio José; Ruiz Zapata, María Blanca; Abel-Schaad, Daniel; Merlo, Oscar; Domínguez Villar, DavidLa depresión de Navamuño se localiza en el tramo de cabecera del valle del río Cuerpo de Hombre (Sierra de Béjar), que durante el Pleistoceno Superior fue ocupado por un glaciar. Se trata de una cubeta tipo nava con una superficie de ~14 Ha, limitada entre laderas correspondientes a escarpes de línea de falla y la morrena lateral izquierda del paleoglaciar de Cuerpo de Hombre. Para conocer la geometría y el espesor de sedimentos de la cuenca así como sus relaciones con las estructuras y formaciones que la delimitan, se han realizado 9 perfiles de tomografía de resistividad eléctrica (TRE) en dos dimensiones (2D), apoyada en 9 sondeos eléctricos verticales (SEV) y dos sondeos mecánicos. Las interpretaciones sugieren un relleno sedimentario de la cubeta de más de unos 20 m de espesor. Genéticamente se interpreta como una cubeta rellena por sedimentos de origen fluvioglaciar y fluviotorrencial, con episodios de tipo lacustre locales y someros.Item Geophysical characterization of the El Cervunal kame complex (Sierra de Gredos, Iberian Central System): Insight of infill geometry and reconstruction of former glacial formations(Journal of applied geophysics, 2021) Granja Bruña, José Luis; Turu, Valenti; Carrasco González, Rosa María; Muñoz Martín, Alfonso; Ros, Xavier; Fernández Lozano, Javier; Soteres, Rodrigo L.; Karampaglidis, Theodoros; López Saez, José Antonio; Pedraza Gilsanz, Javier deGeological and geophysical studies in complex valley troughs provide a key record for the reconstruction of paleoenvironmental conditions during the Quaternary. Here we present a study of the sedimentary infill of the El Cervunal kame complex or El Cervunal trough (Sierra de Gredos, Iberian Central System) by means of a combined interpretation of near-surface geophysical techniques supported by geomorphological and borehole data. A set of 1D and 2D near-surface geophysical methods, including electrical (Vertical Electrical Sounding and 2D Electrical Resistivity Tomography), seismic (2D Seismic Tomography and 1D Refraction Microtremor) and Magnetic Resonance Sounding techniques, were used to test their applicability in providing better insight on the infill nature and geometry. Because of greater sensitivity and higher resolution and coverage achieved with resistivity methods, the electrical resistivity has proven to be the most informative physical parameter, while seismic and magnetic resonance methods were complementary. The sedimentary infill was classified into three geophysical units and five sub-units with their geological interpretation. Unit 1 consists of a postglacial sedimentary sequence and includes alluvial-plain and alluvial-fan deposits. Units 2 and 3 below the postglacial unit were interpreted as glacial sequences including kame (glacigenetic and fluvio-glacial) and morainic deposits, respectively. Subsoil information combined with the geomorphological data enabled the partial reconstruction of the map-view geometry of the morainic bodies at the El Cervunal trough. The results suggest a complex evolution of the study area where erosive-sedimentary processes dominate, but also structural factors should be considered. At least five well-differentiated stages can be established to explain the occurrence of the trough infill: pre-glacial, maximum glacial extension, trough obturation, glacial retreat and periglacial-postglacial.Item 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, RamónThe 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.