Person:
Márquez González, Álvaro

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First Name
Álvaro
Last Name
Márquez González
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Petrología y Geoquímica
Identifiers
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Search Results

Now showing 1 - 10 of 22
  • Publication
    Strength of the lithosphere of Mercury
    (Wiley, 2010) Egea González, Isabel; Ruiz Pérez, Javier; Fernández Rodríguez, Carlos; Márquez González, Álvaro; Lara López, Luisa M.
  • Publication
    New evidence for a volcanically, tectonically, and climatically active Mars
    (Elsevier Science B.V., Amsterdam, 2004) Márquez González, Álvaro; Fernández Caliani, J.C.; Anguita, Francisco; Farelo, Agustín-Felipe; Anguita, Jorge; Casa, Miguel Ángel de la
    Geological analysis of Mars imagery supports the hypothesis that the planet has been the site of recent (< 10 Ma) volcanic and tectonic processes and glacier flow, and makes most likely previous suggestions of continuing endogenic and exogenic activity. Tectonic structures which deform very slightly cratered (at MOC scales) surfaces of Tharsis Montes and surrounding regions seem to attest to active tectonism (both extensional and transcurrent) on Mars. Exogenic processes in this region, such as a glacial origin for the aureole deposits on the northwestern flanks of the Tharsis Montes shield volcanoes, are supported by new data. The very recent age of these structures could be the first direct confirmation that drastic changes in obliquity are modulating the martian climate, such that an increase in obliquity would result in equatorial glaciers taking the place of the receding polar ice caps. If this and other concurring research is extended and confirmed, the ‘alive Mars’ which would emerge would constitute a most appealing place for exobiology and comparative planetology.
  • Publication
    Chasma Boreale, Mars: A Sapping and Outflow Channel with a Tectono-thermal Origin
    (Elsevier Science B.V., Amsterdam, 1997) Benito, G.; Mediavilla, F.; Márquez González, Álvaro; Martínez, J.; Anguita, Francisco
    A detailed geomorphological study of Chasma Boreale, a widely known feature of Mars’ north polar cap, has been carried out for the first time, along with a quantitative paleohydro logical model. It is concluded that the chasma was eroded by a flow whose discharge was on the order of magnitude of 109 m sec21. This catastrophic flow is thought to have been preceded by a powerful sapping process, caused by a tectonic control in the distribution and present aspect of most of the polar troughs. This tectonic forcing probably played a major role in the inception of not only Chasma Boreale but also other polar reentrants as well
  • Publication
    Contrasting catastrophic eruptions predicted by different intrusion and collapse scenarios
    (Nature Publishing Group, 2018-04-18) Rincón, Marta; Márquez González, Álvaro; Herrera, Raquel; Alonso Torres, A.; Granja Bruña, José Luis; Wyk de Vries, Benjamin van
    Catastrophic volcanic eruptions triggered by landslide collapses can jet upwards or blast sideways. Magma intrusion is related to both landslide-triggered eruptive scenarios (lateral or vertical), but it is not clear how such different responses are produced, nor if any precursor can be used for forecasting them. We approach this problem with physical analogue modelling enhanced with X-ray Multiple Detector Computed Tomography scanning, used to track evolution of internal intrusion, and its related faulting and surface deformation. We find that intrusions produce three different volcano deformation patterns, one of them involving asymmetric intrusion and deformation, with the early development of a listric slump fault producing pronounced slippage of one sector. This previously undescribed early deep potential slip surface provides a unified explanation for the two different eruptive scenarios (lateral vs. vertical). Lateral blast only occurs in flank collapse when the intrusion has risen into the sliding block. Otherwise, vertical rather than lateral expansion of magma is promoted by summit dilatation and flank buttressing. The distinctive surface deformation evolution detected opens the possibility to forecast the possible eruptive scenarios: laterally directed blast should only be expected when surface deformation begins to develop oblique to the first major fault.
  • Publication
    Tharsis dome, Mars: New evidence for Noachian-Hesperian tbick-skin and Amazonian thin-skin tectonics
    (American Geophysical Union, 2001-04-25) Anguita, Francisco; Farelo, Agustín-Felipe; López, Valle; Mas, Cristina; Muñoz Espadas, María Jesús; Márquez González, Álvaro; Ruiz Pérez, Javier
    A photogeoIogical reconnaissance of Viking mosaics and images ofthe Tharsis dome has been carried out. Fifteen new areas of transcurrent faulting have been located which, together with other structures previously detected, support a model in which the Thaumasia Plateau, the southeastem part of the Tharsis dome, is proposed to be an independent lithospheric block that experienced buckling and thrust faulting in Late N oachian or Early Hesperian times as a result of an E-W directed compression. Evidence is presented that this stress field, rather than the Tharsis uplift, was decisive in the inception of Valles Marineris, which we consider a transtensive, dextral accident. The buckling spacing permits us, moreover, to tentatively reconstruct a Martian Hesperian lithosphere similar in elastic thickness to the mean present terrestrial oceanic lithosphere, thus supporting the possibility of a restricted lithospheric mobility in that periodo Tharsis lithosphere was again subjected to shear stresses in Amazonian times, a period in which important accidents, such as strike-slip faults, wrinkle ridges, and straight and sigmoidal graben, were formed under a thin-skin tectonic regime, while the lithosphere as a: mechanical unit had become too thick and sttong to buckle. The possible causes of those stresses, and especially their relationships to a putative period of pIate tectonics, are discussed.
  • Publication
    Composición de las lavas asociadas a los colapsos de flanco del sector occidental del Valle de La Orotava (Tenerife)
    (Sociedad Geológica de España, 2022) Ancochea Soto, Eumenio; Huertas Coronel, María José; Márquez González, Álvaro; Herrera, Raquel; Coello Bravo, Juan Jesús
    Se han analizado las lavas de dos galerías de agua excavadas en el valle de La Orotava que cortan la secuencia de relleno de la depresión generada tras el gran colapso de flanco de La Orotava (OL) y los dos colapsos de flancos menores (WOL-1 y WOL-2). Especialmente las lavas situadas inmediatamente encima y debajo de lo depósitos de avalancha asociados al WOL-2 (el U-DAD). Se trata mayoritariamente de basanitas, con algunos términos algo más evolucionados (traquibasaltos y traquiandesitas basálticas). Por sus características químicas parecen pertenecer todas a un mismo sistema magmático y ligadas entre sí por procesos sencillos de fraccionación de clinopiroxeno y, en menor medida, de olivino.Tras el colapso de flanco WOL-2 se aprecia que las rocas son, en general, menos evolucionadas, algo más alcalinas y, con frecuencia, muy ricas en fenocristales máficos.
  • Publication
    Monitoring Volcanic and Tectonic Sandbox Analogue Models Using the Kinect v2 Sensor
    (American Geophysical Union, 2022-06) Rincón, Marta; Márquez González, Álvaro; Herrera, Raquel; Galland, O.; Sánchez Oro, J.; Concha, D.; Montemayor, A. S.
    The measurement of surface deformation in analogue models of volcanic and tectonic processes is an area in continuous development. Properly quantifying topography change in analogue models is key for a useful comparison between experiment results and nature. The aim of this work is to evaluate the capabilities of the simple and cheap Microsoft® Kinect v2 sensor for monitoring analogue models made of granular materials. Microsoft® Kinect v2 is a video-gaming RedGreenBlue-Depth device combining an optical camera and an infrared distance measurement sensor. The precision of the device for model topography measurements has been quantified using 64 experiments, with variable granular materials materials and distance to the model. Additionally, we tested the capabilities of averaging several distance images to increase the precision. We have developed a specific software to facilitate the acquisition and processing of the Kinect v2 data in experiment monitoring. Our results show that measurement precision is material dependent: with clear-colored and fine-grained materials, a precision ∼1.0 mm for digital elevation models with a 1.6 mm pixel size can be obtained. We show that by averaging ≥5 consecutive images the distance precision can reach values as low as 0.5 mm. To show the Kinect v2 capabilities, we present monitoring results from case study experiments modeling tectonics and volcano deformation. The Kinect v2 achieves lower spatial resolutions and precision than more sophisticated techniques such as photogrammetry. However, Kinect v2 provides a cheap, straightforward and powerful tool for monitoring the topography changes in sandbox analogue models.
  • Publication
    The northern Patagonia Somuncura plateau basalts: a product of slab-induced, shallow asthenospheric upwelling?
    (John Wiley & Sons Limited, 2001) De Ignacio, Cristina; Lópe, Iván; Oyarzun, Roberto; Márquez González, Álvaro
    The Meseta de Somuncura forms the largest basaltic plateau (20 000 km2 ) of southern Argentina (extra-Andean domain). Most of these tholeiitic to alkaline rocks were extruded at ~ 25 Ma (late Oligocene). The absence of rifting±thinning processes, plume activity, or slab-window phenomena leaves only one major possibility for the generation of Somuncura: asthenospheric ('OIB-like') corner flow leading to a transient thermal anomaly above the subducting plate. It is suggested herein that the intake of hot asthenosphere was forced into a favourable topography (concave-up) of the subducting plate, hen a major plate reorganization event (Farallon to Nazca) was taking place in late Oligocene to early Miocene time. The fast and vigorous intake of asthenosphere would have been induced by slab roll-back, leading to decoupling of the subducting plate. The Somuncura volcanic episode can be regarded as a marker of the passage from the extremely oblique subduction of Farallon, to the birth of the Nazca plate and roughly perpendicular convergence between South America and Nazca.
  • Publication
    El Chichón Volcano (Chiapas Volcanic Belt, Mexico) Transitional Calc-Alkaline to Adakitic-Like Magmatism: Petrologic and Tectonic Implications
    (Taylor & Francis, 2003) Ignacio San José, Cristina de; Castiñeiras García, Pedro; Márquez González, Álvaro; Oyarzun, Roberto; Lillo Ramos, F. Javier; López Ruiz-Labranderas, Iván
    The rocks of the 1982 eruption of El Chichón volcano (Chiapas, Mexico) display a series of geochemical and mineralogical features that make them a special case within the NW-trending Chiapas volcanic belt. The rocks are transitional between normal arc and adakitic-like trends. They are anhydrite-rich, and were derived from a water-rich, highly oxidized sulfur-rich magma, thus very much resembling adakitic magmas (e.g., the 1991 Pinatubo eruption). We propose that these rocks were generated within a complex plate tectonic scenario involving a torn Cocos plate (Tehuantepec fracture zone) and the ascent of hot asthenospheric mantle. The latter is supported by an outstanding negative S-wave anomaly widely extending beneath the zone, from 70 to 200 km in depth. The adakitic- like trend would be derived from the direct melting of subducting Cocos plate, whereas the transitional rocks would have resulted from the mixing of two poles, one reflecting a mantle source, and the other, the already mentioned adakitic melts. The basaltic source would also account for the high sulfur content and 34S values of the El Chichón system (about +5.8), as result of a contribution of SO2 in fluids released from an underlying mafic magma.
  • Publication
    El proyecto IVRIPARC: metodología para estimar el impacto del cambio globalsobre el patrimonio geológico de los parques nacionales de Canarias
    (Sociedad Geológica de España., 2022) Vegas, J.; Baeza, E.; Díez Herrero, Andrés; Ferrer, N.; Galindo, Inés; Garrote Revilla, Julio; González Laguna, R.; Herrera, Raquel; Lario, Javier; Lozano, G.; Márquez González, Álvaro; Martín González, E.; Mayer, Pablo L.; Perucha, M.A.; Rodríguez Pascua, Miguel Angel; Romero, C.; Sánchez, N.
    El patrimonio geológico y la geodiversidad de los parques nacionales contribuyen, junto con la biodiversidad, para que sean espacios naturales protegidos únicos en el país, pero también únicos a nivel mundial. El patrimonio geológico es de carácter no renovable, de tal forma que, si se pierden o degradan, lo hacen para siempre. Ante el escenario del cambio global, el patrimonio geológico de los parques nacionales canarios es muy vulnerable a los impactos rovocados por los cambios en la temperatura, avenidas torrenciales, tormentas extremas, sequías, desertificación y ascenso del nivel del mar, fundamentalmente, y a los impactos derivados de la actividad humana. Estos fenómenos provocan la activación de procesos geológicos que afectan directamente a su conservación, de tal forma que es necesario identificar los Lugares de Interés Geológico más amenazados, evaluar su incidencia y establecer los indicadores a escala de cada parque nacional para realizar su seguimiento. Conocer el estado de conservación actual, su vulnerabilidad y sus amenazas directas contribuirá a la gestión de los parques para el proceso de adaptación y mitigación del cambio global.