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Papers by GERARDO DE VICENTE MUÑOZ

Research paper thumbnail of Localización de fallas neotectónicas mediante VLF-EM en el borde sur del Sistema Central (Zona de Tamajón)

espanolDada la imposibilidad de utilizar metodos convencionales, se emplea el metodo VLF-EM para ... more espanolDada la imposibilidad de utilizar metodos convencionales, se emplea el metodo VLF-EM para la localizacion de fallas neotectonicas en la zona de Tamajon (borde sur del Sistema Central). De este modo se obtiene un diseno de fracturacion que sigue cualitativamente el modelo de RECHES (1983, senalando una etapa distensiva al Plioceno Superior de direccion NW-SE. EnglishGiven the hopelessness of using conventional methods it is used the VLF-EM method for Neotectonic faults location in the Tamajon area (Sistema Central south edge). Pattern fracturation follows RECHES model (1983), showing a distentional period after Upper Pliocene with NW-SE direction.

Research paper thumbnail of A public domain model for 1D temperature and rheology construction in basement-sedimentary geothermal exploration: an application to the Spanish Central System and adjacent basins

Acta geodaetica et geophysica, Mar 16, 2017

Brittle basement and sedimentary rocks, in particular if these are underlain by radiogenic crust,... more Brittle basement and sedimentary rocks, in particular if these are underlain by radiogenic crust, are considered a prime target for enhanced geothermal systems (EGS). They are marked by high geothermal gradients, caused by radiogenic heat production, and are well suited to be used for geothermal doublets after hydraulic stimulation. Critical conditions for successful EGS projects are: (a) tectonic stresses close to failure, allowing creation of induced fractures by means of hydraulic stimulation; (b) sufficient high temperatures [150°C, preferably in excess of 200°C, at depths of less than 5 km; (c) sufficient high water flow rates, to be sustained through induced fractures. For geothermal production, knowledge on thermomechanical properties of the lithosphere provides critical constraints on crustal stresses and basement temperatures. We developed a freely available 1D thermal and rheological model for basement-sedimentary areas. This tool helps to understand variability of deep temperatures, as an effect of uncertainties in thermal and rheological properties and tectonic constraints for the lithosphere, important for assessing geothermal prospectivity. The tool is demonstrated on the Central System in Spain and the adjacent Tajo and Duero basins. Keywords Enhanced geothermal systems Á Thermo-mechanical models Á Geothermal exploration Á Iberia 1 Introduction Economics limit development of enhanced geothermal systems (EGS) to areas with elevated geothermal gradients. Sufficient high temperatures ([150°C, preferably in excess of 200°C) are required at depths of less than 5 km, partly due to increasing drilling costs (e.g.

Research paper thumbnail of Estabilidad de la barrera geológica: estudios neotectónicos, sismotectónicos y paleosismológicos

Research paper thumbnail of Role of multiple inherited basement structures on orogen geometry and evolution: Insights from analogue modelling

Journal of Structural Geology, 2021

Abstract The role of inherited weaknesses in metamorphic basements with respect to the geometry a... more Abstract The role of inherited weaknesses in metamorphic basements with respect to the geometry and tectonic evolution of subsequent orogens formation forms a cornerstone of structural reconstructions, especially in non-inverted orogens with old Variscan basements. In this study, we analyse the geometry, kinematics, and tectonic evolution of the complex western termination of the Alpine Pyrenean–Cantabrian orogen using an integrated approach based on analogue modelling, constrained by structural mapping and geochronology, to provide new insights into the role of pre-existing structures and the shift in the orientation of the stress field. Our results demonstrate that pre-existing structures are necessary to explain the complex western termination, which does not follow the same tectonic architecture as the rest of the orogen. The reason for this is the different orientation of the pre-existing Variscan structures in this area, which do not follow the general E–W trend. These western structures (including NNE–SSW and NW–SE strike-slip fault systems and a greater number of E–W thrusts) accommodate the shortening, but have a less favourable orientation. The reactivation of the NNE–SSW strike-slip faults and the southern E–W thrusts in the recent stages indicates a late intraplate tectonic regime, mainly following the shift of the Shmax (from N–S to NNW–SSE) which occurred when the convergence between the Iberian, Eurasian, and African plates changed.

Research paper thumbnail of Mechanisms and age estimates of continental-scale endorheic to exorheic drainage transition: Douro River, Western Iberia

Global and Planetary Change, 2019

Mechanisms and age estimates of continental-scale endorheic to exorheic drainage transition: Dour... more Mechanisms and age estimates of continental-scale endorheic to exorheic drainage transition: Douro River,

Research paper thumbnail of Strength of the Iberian intraplate lithosphere: Cenozoic deformations and seismicity

Journal of Iberian Geology, 2016

Previous studies about the strength of the lithosphere in the center of Iberia fail to resolve th... more Previous studies about the strength of the lithosphere in the center of Iberia fail to resolve the depth of earthquakes because of the rheological uncertainties. Therefore, new contributions are considered (the crustal structure from a density model) and several parameters (tectonic regime, mantle rheology, strain rate) are checked in this paper to properly examine the role of lithospheric strength in the intraplate seismicity and the Cenozoic evolution. The strength distribution with depth, the integrated strength, the effective elastic thickness and the seismogenic thickness have been calculated by a finite element modelling of the lithosphere across the Central System mountain range and the bordering Duero and Madrid sedimentary basins. Only a dry mantle under strike-slip/extension and a strain rate of 10-15 s-1 , or under extension and 10-16 s-1 , causes a strong lithosphere. The integrated strength and the elastic thickness are lower in the mountain chain than in the basins. This heterogeneity has been maintained since the Cenozoic and determine the mountain uplift and the biharmonic folding of the Iberian lithosphere during the Alpine deformations. The seismogenic thickness bounds the seismic activity in the upper-middle crust, and the decreasing crustal strength from the Duero Basin towards the Madrid Basin is related to a parallel increase in Plio-Quaternary deformations and seismicity. However, elasto-plastic modelling shows that current African-Eurasian convergence is resolved elastically or ductilely, which accounts for the low seismicity recorded in this region.

Research paper thumbnail of Modelación análoga de pliegues litosféricos del Microcontinente Iberia

La deformación de la Península Ibérica es el resultado de la convergencia entre las Placas Africa... more La deformación de la Península Ibérica es el resultado de la convergencia entre las Placas Africana y Europea durante el Terciario. El relieve resultante está relacionado con " buckling " litosférico, que reproduce la reactivación de estructuras del basamento (corredores de fallas) y la inversión de " rifts " Mesozoicos. La distribución espacial de las elevaciones topográficas en la placa Ibérica refleja la compleja interacción de los procesos corticales y litosféricos. Mediante modelación análoga, el presente trabajo estudia la interacción de capas corticales y mantélicas en términos de su expresión topográfica y estructural así como la/s longitudes de onda de la deformación. Los resultados preliminares muestran que la primera respuesta al acortamiento es el plegamiento litosférico en diferentes longitudes de onda, reflejando las diferencias en las propiedades reológicas de las capas litosféricas. El engrosamiento litosférico de la corteza dúctil está acompañado...

Research paper thumbnail of Cuantificación de la deformación asociada a la falla de Berzosa (Sistema Central Español)

En relación con la zona de cizalla dúctil de Berzosa Honrubia que actúa durante la segunda fase d... more En relación con la zona de cizalla dúctil de Berzosa Honrubia que actúa durante la segunda fase de deformación Hercínica, se han calculado los elipsoides de deformación finita asociados a la misma. Para el cálculo se usan los métodos de Ramsay (1967), Dunnet (1969), y Fry (1979). Los resultados muestran una variación en el tipo de elipsoide a lo largo de la traza de la zona de cizalla. En los extremos tienen valores K> t, y en la parte central de K < 1 .

Research paper thumbnail of Lithospheric folding in Iberia

Tectonics, 2002

Integration of stress indicator data, gravity data, crustal kinematics data, and analysis of topo... more Integration of stress indicator data, gravity data, crustal kinematics data, and analysis of topography and recent vertical motions demonstrates the occurrence of consistently oriented spatial patterns of large‐scale Alpine to recent intraplate deformation in Iberia. The inferred upper crustal and lithospheric deformation patterns and the timing of the associated expressions at or near the surface support the existence of a close coupling with plate boundary processes operating at the margins of Iberia. Patterns of lithosphere and upper crustal folds are oriented perpendicular to the main axis of present‐day intraplate compression in Iberia inferred from structural analysis of stress indicator data and focal mechanism solutions. These findings suggest the presence of lithospheric folds, with wavelengths compatible with theoretical predictions of folding wavelengths of Variscan lithosphere. Stress‐induced intraplate deformation set up by plate interactions is compatible with indicati...

Research paper thumbnail of Local stress fields and intraplate deformation of Iberia: Variations in spatial and temporal interplay of regional stress sources

Tectonophysics, 1999

Tertiary to present deformation in the interior of the Iberian Peninsula reflects spatial and tem... more Tertiary to present deformation in the interior of the Iberian Peninsula reflects spatial and temporal variations of the activity of the plate boundaries. Local deformation patterns observed in many of the numerous intraplate Tertiary basins and their borders, such as the Madrid Basin and the Sierra de Altomira, are at first sight incompatible with the regional stress field under which they were formed. We demonstrate, however, that they can be explained as the effect of several stress fields that acted on the Iberian Peninsula from earliest Tertiary onward. Data on local deformation can constrain both magnitudes and directions of forces acting on the plate boundaries of Iberia, enabling us to estimate the relative importance of the different plate driving and deforming mechanisms providing further constraints on the tectonic evolution of Iberia.

Research paper thumbnail of TOPO-EUROPE: From Iberia to the Carpathians and analogues

Tectonophysics, 2011

Earth Sciences are rapidly changing from largely descriptive to process-oriented disciplines that... more Earth Sciences are rapidly changing from largely descriptive to process-oriented disciplines that aim at quantitative models for the reconstruction and forecasting of the complex processes in the Solid Earth. Prediction is highly relevant for the basic needs of humanity: supply of water and resources, protection against natural hazards and control on the environmental degradation of the Earth. Intensive utilization of the human habitat carries largely unknown risks of and makes us increasingly vulnerable. There is an urgent need for scientifically advanced "geo-prediction systems" that can accurately locate subsurface resources and forecast timing and magnitude of natural hazards. The design of such systems is a major multidisciplinary scientific challenge. The quantitative understanding of the Earth has made significant progress in the last few decades. Important ingredients in this process have been the advances made in seismological methods to obtain information on the 3D structure of the mantle and the lithosphere, in the quantitative understanding of the lithospheric processes as well as the recognition of the key role of quantitative sedimentary basin analysis in connecting temporal and spatial scales. Quantitative understanding of the mass transfer by erosion and deposition as well as their feed back with crustal and subcrustal dynamics presents a new frontier in modern Earth sciences. This research bridges investigations on high-resolution, near-surface time scales and the largescale, long-term approaches characteristic for the lithosphere and basin-wide studies. The essential step towards a 4D approach (in space and time) is a direct response to the need for a full incorporation of geological and geophysical constraints in the modelling of solid Earth processes. TOPO-EUROPE is a multidisciplinary international research program that addresses the interaction of processes inherent to the deep Earth (lithosphere and mantle) with surface processes (erosion, climate and sea level), which together shaped the topography of Europe. The objective of this programme is to quantify natural hazards by incorporating data interactive modelling focused on the lithosphere memory and neotectonics, with special attention on the thermo-mechanical structure of the lithosphere, mechanisms controlling large-scale plate boundaries and intraplate deformations, anomalous subsidence and uplift, and links with surface processes and topography evolution.

Research paper thumbnail of Large-scale distributed deformation controlled topography along the western Africa–Eurasia limit: Tectonic constraints

Tectonophysics, 2009

In the interior of the Iberian Peninsula, the main geomorphic features, mountain ranges and basin... more In the interior of the Iberian Peninsula, the main geomorphic features, mountain ranges and basins, seems to be arranged in several directions whose origin can be related to the N-S plate convergence which occurred along the Cantabro-Pyrenean border during the Eocene-Lower Miocene time span. The Iberian Variscan basement accommodated part of this plate convergence in three E-W trending crustal folds as well as in the reactivation of two left-lateral NNE-SSW strike-slip belts. The rest of the convergence was assumed through the inversion of the Iberian Mesozoic Rift to form the Iberian Chain. This inversion gave rise to a process of oblique crustal shortening involving the development of two right lateral NW-SE shear zones. Crustal folds, strike-slip corridors and one inverted rift compose a tectonic mechanism of pure shear in which the shortening is solved vertically by the development of mountain ranges and related sedimentary basins. This model can be expanded to NW Africa, up to the Atlasic System, where N-S plate convergence seems also to be accommodated in several basement uplifts, Anti-Atlas and Meseta, and through the inversion of two Mesozoic rifts, High and Middle Atlas. In this tectonic situation, the microcontinent Iberia used to be rmly attached to Africa during most part of the Tertiary, in such a way that N-S compressive stresses could be transmitted from the collision of the Pyrenean boundary. This tectonic scenario implies that most part of the Tertiary Eurasia-Africa convergence was not accommodated along the Iberia-Africa interface, but in the Pyrenean plateboundary. A broad zone of distributed deformation resulted from the transmission of compressive stresses from the collision at the Pyrenean border. This distributed, intraplate deformation, can be easily related to the topographic pattern of the Africa-Eurasia interface at the longitude of the Iberian Peninsula. Shortening in the Rif-Betics external zones-and their related topographic features-must be conversely related to more "local " driven mechanisms, the westward displacement of the "exotic " Alboran domain, other than N-S convergence. The remaining NNW-SSE to NW-SE, latest Miocene up to Present convergence is also being accommodated in this zone straddling Iberia and Morocco, at the same time as a new ill-de ned plate boundary that is being developed between Europe and Africa.

Research paper thumbnail of Integrated gravity and topography analysis in analog models: Intraplate deformation in Iberia

Tectonics, 2012

Trends in the topography of the Iberian Peninsula show a pronounced contrast. In the western part... more Trends in the topography of the Iberian Peninsula show a pronounced contrast. In the western part of the Iberian microplate the main topographic highs trend E‐W to NE‐SW and are periodically spaced with wavelengths of 250 km. Conversely, in the northeastern part, the region of the Iberian Chain, topography is more irregular and strike directions vary from NW‐SE to E‐W and NE‐SW. We relate this phenomenon to shortening of a continental lithosphere, which contains two different, well‐defined domains of lithospheric strength. Our hypothesis is supported by physical analog models. A new processing method has been developed to assist the interpretation of the model results. It utilizes spectral analysis of gravity and topography data derived from the experiments. Folding of the crust and mantle lithosphere yields periodic gravity fluctuations, while thickening processes lead to localized gravity lows. In this way gravity data can be used to distinguish between the two forms of lithospher...

Research paper thumbnail of The role of lithospheric heterogeneities in the location of the Cenozoic intraplate deformation of Iberia from finite element modeling

Tectonics, 2012

The Cenozoic evolution of the Central System basement uplift and of the continental Duero and Mad... more The Cenozoic evolution of the Central System basement uplift and of the continental Duero and Madrid basins on the Iberian Peninsula occurred in a compressive context triggered by the Alpine orogeny. Although several models of deformation have been suggested, the factors that led to the development of these have not been analyzed to date. We present here finite element modeling of the intraplate deformation of the Iberian lithosphere during the Cenozoic. This modeling has taken into account the role played by (1) the tectonic shortening originating from the Pyrenean and Betic collisions, (2) the weight of Tertiary continental sediments, and (3) thermomechanical heterogeneities present in the lithosphere. The numerical model represents a lithospheric section, with a creep-type mechanical behavior, perpendicular to the Central System, and the two sedimentary basins. Both initial conditions and the results obtained have been specified based on the available geophysical and geological data. This study has enabled us to simulate the present lithospheric structure of the central Iberian peninsula: (a) the formation of the Central System relief and its horizontal shortening, (b) the basement folding in the Duero and Madrid basins, (c) the development of the root of the mountain range, and (d) the depth of the lithosphere-asthenosphere border in the interior of Iberia. The deformations occurred through a large-scale folding and thickening mechanism, by the shortening of a lithosphere that was initially thinner, and with lateral contrasts in temperatures and composition.

Research paper thumbnail of The recent (upper Miocene to Quaternary) and present tectonic stress distributions in the Iberian Peninsula

Tectonics, 2000

A general synthesis of the recent and present stress situation and evolution in the Iberian Penin... more A general synthesis of the recent and present stress situation and evolution in the Iberian Peninsula was obtained from microstructural and seismological analysis. The stress evolution was deduced from (1) fault population analysis (FPA) from 409 sites distributed throughout the Iberian Peninsula, (2) paleostress indicators given by 324 stations taken from the bibliography, and (3) seismic data corresponding to 161 focal mechanisms evenly spread in the studied region. The application of FPA together with the determination of stress tensors and focal mechanisms for the whole Iberian microplate has provided two main results: (1) the Iberian Peninsula is undergoing a NW‐SE oriented compression, except for the northeastern part (Pyrenees, Ebro Basin, and Iberian Chain), where it is N‐S to NE‐SW, and the Gulf of Cádiz, where it seems to be E‐W, and (2) the main trends of the stress field have remained almost constant since the upper Miocene. The analysis performed by zones suggests the p...

Research paper thumbnail of Microdeformation of lacustrine laminite sequences from Late Miocene formations of SE Spain: an interpretation of loop bedding

Sedimentology, 1998

Lacustrine laminated sediments (laminites) present in Late Miocene formations of the Híjar Basin,... more Lacustrine laminated sediments (laminites) present in Late Miocene formations of the Híjar Basin, SE Spain, display well developed loop bedding, a structure consisting of bundles of laminae that are sharply constricted at intervals, giving a morphology of loops or links of a chain. The laminite sequences, which are interbedded with turbidite marlstones, were accumulated on the bottom of a permanently stratified lake developed in a rapidly subsiding basin limited by 010° and 105° normal faults. As deduced from both macro‐ and microdeformational analyses, the basin evolved under an extensional stress field throughout the Late Miocene. Four main types of loops, simple and complex loops with subcategories, have been recognized within the laminite sequence. Simple loops of type 1 show the best definite pattern, quite similar to ‘pinch and swell structures’, a type of boudinage typical of stretching of alternating beds where the competence contrast is not strongly marked. The remaining lo...

Research paper thumbnail of Soft-sediment deformation structures interpreted as seismites in lacustrine sediments of the Prebetic Zone, SE Spain, and their potential use as indicators of earthquake magnitudes during the Late Miocene

Sedimentary Geology, 2000

Lacustrine formations of Late Miocene age in the Prebetic area, SE Spain, show several types of d... more Lacustrine formations of Late Miocene age in the Prebetic area, SE Spain, show several types of deformational structures that are interpreted as seismites. They are present in both marginal and deep lacustrine facies. Seismites formed in marginal lake environments comprise sand dikes, pillows and intruded and fractured gravels. In deep lacustrine facies, the seismites are represented by pseudonodules, mushroom-like silts protruding into laminites, mixed layers, disturbed varved lamination and loop bedding. The measured orientations of these structures are consistent with the orientations of the main faults limiting the basins, showing that their origin is clearly related to the tectonic stress field that prevailed in the region during the Late Miocene. The magnitudes of the earthquakes that deformed the sediments have been estimated after published data from both ancient and recent lake deposits accumulated in tectonic active regions elsewhere. A rank of earthquake magnitudes with two end-members, i.e. the lowest magnitudes recorded by loop bedding in laminites and the highest magnitudes represented by intruded and fractured gravels, is proposed.

Research paper thumbnail of Similarities between recent seismic activity and paleoseismites during the late miocene in the external Betic Chain (Spain): relationship by ‘b’ value and the fractal dimension

Journal of Structural Geology, 2003

A paleoseismic data set derived from the relationship between the thickness of seismites, 'mixed ... more A paleoseismic data set derived from the relationship between the thickness of seismites, 'mixed layers' in lacustrine Miocene deposits and the magnitude of the earthquakes is presented. The relationship between both parameters was calibrated by the threshold of fluidification limits in the interval of magnitude 5 and 5.5. The mixed layers (deformational sediment structures due to seismic activity) were observed in varved sediments from three Neogene lacustrine basins near Hellín (Albacete, Spain), El Cenajo, Elche de la Sierra and Híjar, and are interpreted as liquefaction features due to seismic phenomena. These paleoseismic structures were dated (relative values) by measurements of cyclic annual sedimentation in the varved sediments. From these observations, we are able to establish a recurrence interval of 130 years with events for magnitude bigger than or equal to four. Both paleoseismicity and instrumental seismicity data sets obey the Gutenberg-Richter law and the 'b' value is close to 0.86. The fractal dimension (dimension of capacity) of spatial distribution of potentially active faults (faults oriented according to the stress tensor regime in the area) was measured by the box-counting technique (D 0 = 1.73). According to the Aki empirical relation (D 0 = 2b) for the instrumental seismicity and paleoseismic data sets in the area, the fractal dimension is close to 1.72. The similar value of the fractal dimension obtained by both techniques shows homogeneous seismic dynamics during the studied time interval. Moreover, the better established 'b' value of the paleoseismic data sets (0.86) compared with the 'b' value for the incomplete historic seismicity (<0.5) in the area increases the seismic series beyond the historic seismic record.

Research paper thumbnail of Quantification of fluvial incision in the Duero Basin (NW Iberia) from longitudinal profile analysis and terrestrial cosmogenic nuclide concentrations

Research paper thumbnail of Using river long profiles and geomorphic indices to evaluate the geomorphological signature of continental scale drainage capture, Duero basin (NW Iberia)

Geomorphology, 2014

ABSTRACT Well-constrained case studies of transient landscape responses are needed to improve our... more ABSTRACT Well-constrained case studies of transient landscape responses are needed to improve our understanding of erosion processes associated with drainage captures. The Duero basin is an excellent location for such a study because the landscape is currently undergoing pronounced geomorphological changes resulting from the opening of a former closed drainage. The present-day continental interior basin (&amp;gt; 50,000 km2) drains to the Atlantic Ocean via the Duero River, but during the Cenozoic the basin experienced a long endorheic period marked by the formation of evaporites. Currently, the entire continental interior is an area of relative tectonic quiescence, characterised by a relict low-relief upland topography (Meseta). Systematic variations in lithology and a well-constrained tectonic setting throughout the basin and adjacent areas allow for the comparison of channel morphology between the Cenozoic Duero basin and its western fringe. To explore the signal of transient geomorphic response to capture and opening of the former endorheic basin, the main channel and 24 tributaries were analysed in terms of their longitudinal profiles and the application of geomorphic indices (concavity index [Ci], valley floor width-to-height ratio [Vf], and stream-length gradient index [SL]). The analysis reveals two zones with distinctive morphologies: (1) an upper reach domain consisting of broad flat valleys and low-gradient streams where concave longitudinal profiles dominate and (2) a middle reach domain characterised by steep, deeply incised canyons where a convex long profile dominates marking a major kinckzone. The quantitative information on channel shapes and long profile geometries allows the interpretation of these patterns in terms of driving forces for fluvial landscape development. Large-scale morphometric analysis highlights the transient response of the entire basin to a capture-related base level lowering and illustrates the importance of drainage captures as potential internal drivers of landscape modification and topographic adjustments. Furthermore, the Duero basin case study also emphasises that well-constrained bedrock geology and tectonic patterns are essential to avoid misinterpretation of geomorphic indexes.

Research paper thumbnail of Localización de fallas neotectónicas mediante VLF-EM en el borde sur del Sistema Central (Zona de Tamajón)

espanolDada la imposibilidad de utilizar metodos convencionales, se emplea el metodo VLF-EM para ... more espanolDada la imposibilidad de utilizar metodos convencionales, se emplea el metodo VLF-EM para la localizacion de fallas neotectonicas en la zona de Tamajon (borde sur del Sistema Central). De este modo se obtiene un diseno de fracturacion que sigue cualitativamente el modelo de RECHES (1983, senalando una etapa distensiva al Plioceno Superior de direccion NW-SE. EnglishGiven the hopelessness of using conventional methods it is used the VLF-EM method for Neotectonic faults location in the Tamajon area (Sistema Central south edge). Pattern fracturation follows RECHES model (1983), showing a distentional period after Upper Pliocene with NW-SE direction.

Research paper thumbnail of A public domain model for 1D temperature and rheology construction in basement-sedimentary geothermal exploration: an application to the Spanish Central System and adjacent basins

Acta geodaetica et geophysica, Mar 16, 2017

Brittle basement and sedimentary rocks, in particular if these are underlain by radiogenic crust,... more Brittle basement and sedimentary rocks, in particular if these are underlain by radiogenic crust, are considered a prime target for enhanced geothermal systems (EGS). They are marked by high geothermal gradients, caused by radiogenic heat production, and are well suited to be used for geothermal doublets after hydraulic stimulation. Critical conditions for successful EGS projects are: (a) tectonic stresses close to failure, allowing creation of induced fractures by means of hydraulic stimulation; (b) sufficient high temperatures [150°C, preferably in excess of 200°C, at depths of less than 5 km; (c) sufficient high water flow rates, to be sustained through induced fractures. For geothermal production, knowledge on thermomechanical properties of the lithosphere provides critical constraints on crustal stresses and basement temperatures. We developed a freely available 1D thermal and rheological model for basement-sedimentary areas. This tool helps to understand variability of deep temperatures, as an effect of uncertainties in thermal and rheological properties and tectonic constraints for the lithosphere, important for assessing geothermal prospectivity. The tool is demonstrated on the Central System in Spain and the adjacent Tajo and Duero basins. Keywords Enhanced geothermal systems Á Thermo-mechanical models Á Geothermal exploration Á Iberia 1 Introduction Economics limit development of enhanced geothermal systems (EGS) to areas with elevated geothermal gradients. Sufficient high temperatures ([150°C, preferably in excess of 200°C) are required at depths of less than 5 km, partly due to increasing drilling costs (e.g.

Research paper thumbnail of Estabilidad de la barrera geológica: estudios neotectónicos, sismotectónicos y paleosismológicos

Research paper thumbnail of Role of multiple inherited basement structures on orogen geometry and evolution: Insights from analogue modelling

Journal of Structural Geology, 2021

Abstract The role of inherited weaknesses in metamorphic basements with respect to the geometry a... more Abstract The role of inherited weaknesses in metamorphic basements with respect to the geometry and tectonic evolution of subsequent orogens formation forms a cornerstone of structural reconstructions, especially in non-inverted orogens with old Variscan basements. In this study, we analyse the geometry, kinematics, and tectonic evolution of the complex western termination of the Alpine Pyrenean–Cantabrian orogen using an integrated approach based on analogue modelling, constrained by structural mapping and geochronology, to provide new insights into the role of pre-existing structures and the shift in the orientation of the stress field. Our results demonstrate that pre-existing structures are necessary to explain the complex western termination, which does not follow the same tectonic architecture as the rest of the orogen. The reason for this is the different orientation of the pre-existing Variscan structures in this area, which do not follow the general E–W trend. These western structures (including NNE–SSW and NW–SE strike-slip fault systems and a greater number of E–W thrusts) accommodate the shortening, but have a less favourable orientation. The reactivation of the NNE–SSW strike-slip faults and the southern E–W thrusts in the recent stages indicates a late intraplate tectonic regime, mainly following the shift of the Shmax (from N–S to NNW–SSE) which occurred when the convergence between the Iberian, Eurasian, and African plates changed.

Research paper thumbnail of Mechanisms and age estimates of continental-scale endorheic to exorheic drainage transition: Douro River, Western Iberia

Global and Planetary Change, 2019

Mechanisms and age estimates of continental-scale endorheic to exorheic drainage transition: Dour... more Mechanisms and age estimates of continental-scale endorheic to exorheic drainage transition: Douro River,

Research paper thumbnail of Strength of the Iberian intraplate lithosphere: Cenozoic deformations and seismicity

Journal of Iberian Geology, 2016

Previous studies about the strength of the lithosphere in the center of Iberia fail to resolve th... more Previous studies about the strength of the lithosphere in the center of Iberia fail to resolve the depth of earthquakes because of the rheological uncertainties. Therefore, new contributions are considered (the crustal structure from a density model) and several parameters (tectonic regime, mantle rheology, strain rate) are checked in this paper to properly examine the role of lithospheric strength in the intraplate seismicity and the Cenozoic evolution. The strength distribution with depth, the integrated strength, the effective elastic thickness and the seismogenic thickness have been calculated by a finite element modelling of the lithosphere across the Central System mountain range and the bordering Duero and Madrid sedimentary basins. Only a dry mantle under strike-slip/extension and a strain rate of 10-15 s-1 , or under extension and 10-16 s-1 , causes a strong lithosphere. The integrated strength and the elastic thickness are lower in the mountain chain than in the basins. This heterogeneity has been maintained since the Cenozoic and determine the mountain uplift and the biharmonic folding of the Iberian lithosphere during the Alpine deformations. The seismogenic thickness bounds the seismic activity in the upper-middle crust, and the decreasing crustal strength from the Duero Basin towards the Madrid Basin is related to a parallel increase in Plio-Quaternary deformations and seismicity. However, elasto-plastic modelling shows that current African-Eurasian convergence is resolved elastically or ductilely, which accounts for the low seismicity recorded in this region.

Research paper thumbnail of Modelación análoga de pliegues litosféricos del Microcontinente Iberia

La deformación de la Península Ibérica es el resultado de la convergencia entre las Placas Africa... more La deformación de la Península Ibérica es el resultado de la convergencia entre las Placas Africana y Europea durante el Terciario. El relieve resultante está relacionado con " buckling " litosférico, que reproduce la reactivación de estructuras del basamento (corredores de fallas) y la inversión de " rifts " Mesozoicos. La distribución espacial de las elevaciones topográficas en la placa Ibérica refleja la compleja interacción de los procesos corticales y litosféricos. Mediante modelación análoga, el presente trabajo estudia la interacción de capas corticales y mantélicas en términos de su expresión topográfica y estructural así como la/s longitudes de onda de la deformación. Los resultados preliminares muestran que la primera respuesta al acortamiento es el plegamiento litosférico en diferentes longitudes de onda, reflejando las diferencias en las propiedades reológicas de las capas litosféricas. El engrosamiento litosférico de la corteza dúctil está acompañado...

Research paper thumbnail of Cuantificación de la deformación asociada a la falla de Berzosa (Sistema Central Español)

En relación con la zona de cizalla dúctil de Berzosa Honrubia que actúa durante la segunda fase d... more En relación con la zona de cizalla dúctil de Berzosa Honrubia que actúa durante la segunda fase de deformación Hercínica, se han calculado los elipsoides de deformación finita asociados a la misma. Para el cálculo se usan los métodos de Ramsay (1967), Dunnet (1969), y Fry (1979). Los resultados muestran una variación en el tipo de elipsoide a lo largo de la traza de la zona de cizalla. En los extremos tienen valores K> t, y en la parte central de K < 1 .

Research paper thumbnail of Lithospheric folding in Iberia

Tectonics, 2002

Integration of stress indicator data, gravity data, crustal kinematics data, and analysis of topo... more Integration of stress indicator data, gravity data, crustal kinematics data, and analysis of topography and recent vertical motions demonstrates the occurrence of consistently oriented spatial patterns of large‐scale Alpine to recent intraplate deformation in Iberia. The inferred upper crustal and lithospheric deformation patterns and the timing of the associated expressions at or near the surface support the existence of a close coupling with plate boundary processes operating at the margins of Iberia. Patterns of lithosphere and upper crustal folds are oriented perpendicular to the main axis of present‐day intraplate compression in Iberia inferred from structural analysis of stress indicator data and focal mechanism solutions. These findings suggest the presence of lithospheric folds, with wavelengths compatible with theoretical predictions of folding wavelengths of Variscan lithosphere. Stress‐induced intraplate deformation set up by plate interactions is compatible with indicati...

Research paper thumbnail of Local stress fields and intraplate deformation of Iberia: Variations in spatial and temporal interplay of regional stress sources

Tectonophysics, 1999

Tertiary to present deformation in the interior of the Iberian Peninsula reflects spatial and tem... more Tertiary to present deformation in the interior of the Iberian Peninsula reflects spatial and temporal variations of the activity of the plate boundaries. Local deformation patterns observed in many of the numerous intraplate Tertiary basins and their borders, such as the Madrid Basin and the Sierra de Altomira, are at first sight incompatible with the regional stress field under which they were formed. We demonstrate, however, that they can be explained as the effect of several stress fields that acted on the Iberian Peninsula from earliest Tertiary onward. Data on local deformation can constrain both magnitudes and directions of forces acting on the plate boundaries of Iberia, enabling us to estimate the relative importance of the different plate driving and deforming mechanisms providing further constraints on the tectonic evolution of Iberia.

Research paper thumbnail of TOPO-EUROPE: From Iberia to the Carpathians and analogues

Tectonophysics, 2011

Earth Sciences are rapidly changing from largely descriptive to process-oriented disciplines that... more Earth Sciences are rapidly changing from largely descriptive to process-oriented disciplines that aim at quantitative models for the reconstruction and forecasting of the complex processes in the Solid Earth. Prediction is highly relevant for the basic needs of humanity: supply of water and resources, protection against natural hazards and control on the environmental degradation of the Earth. Intensive utilization of the human habitat carries largely unknown risks of and makes us increasingly vulnerable. There is an urgent need for scientifically advanced "geo-prediction systems" that can accurately locate subsurface resources and forecast timing and magnitude of natural hazards. The design of such systems is a major multidisciplinary scientific challenge. The quantitative understanding of the Earth has made significant progress in the last few decades. Important ingredients in this process have been the advances made in seismological methods to obtain information on the 3D structure of the mantle and the lithosphere, in the quantitative understanding of the lithospheric processes as well as the recognition of the key role of quantitative sedimentary basin analysis in connecting temporal and spatial scales. Quantitative understanding of the mass transfer by erosion and deposition as well as their feed back with crustal and subcrustal dynamics presents a new frontier in modern Earth sciences. This research bridges investigations on high-resolution, near-surface time scales and the largescale, long-term approaches characteristic for the lithosphere and basin-wide studies. The essential step towards a 4D approach (in space and time) is a direct response to the need for a full incorporation of geological and geophysical constraints in the modelling of solid Earth processes. TOPO-EUROPE is a multidisciplinary international research program that addresses the interaction of processes inherent to the deep Earth (lithosphere and mantle) with surface processes (erosion, climate and sea level), which together shaped the topography of Europe. The objective of this programme is to quantify natural hazards by incorporating data interactive modelling focused on the lithosphere memory and neotectonics, with special attention on the thermo-mechanical structure of the lithosphere, mechanisms controlling large-scale plate boundaries and intraplate deformations, anomalous subsidence and uplift, and links with surface processes and topography evolution.

Research paper thumbnail of Large-scale distributed deformation controlled topography along the western Africa–Eurasia limit: Tectonic constraints

Tectonophysics, 2009

In the interior of the Iberian Peninsula, the main geomorphic features, mountain ranges and basin... more In the interior of the Iberian Peninsula, the main geomorphic features, mountain ranges and basins, seems to be arranged in several directions whose origin can be related to the N-S plate convergence which occurred along the Cantabro-Pyrenean border during the Eocene-Lower Miocene time span. The Iberian Variscan basement accommodated part of this plate convergence in three E-W trending crustal folds as well as in the reactivation of two left-lateral NNE-SSW strike-slip belts. The rest of the convergence was assumed through the inversion of the Iberian Mesozoic Rift to form the Iberian Chain. This inversion gave rise to a process of oblique crustal shortening involving the development of two right lateral NW-SE shear zones. Crustal folds, strike-slip corridors and one inverted rift compose a tectonic mechanism of pure shear in which the shortening is solved vertically by the development of mountain ranges and related sedimentary basins. This model can be expanded to NW Africa, up to the Atlasic System, where N-S plate convergence seems also to be accommodated in several basement uplifts, Anti-Atlas and Meseta, and through the inversion of two Mesozoic rifts, High and Middle Atlas. In this tectonic situation, the microcontinent Iberia used to be rmly attached to Africa during most part of the Tertiary, in such a way that N-S compressive stresses could be transmitted from the collision of the Pyrenean boundary. This tectonic scenario implies that most part of the Tertiary Eurasia-Africa convergence was not accommodated along the Iberia-Africa interface, but in the Pyrenean plateboundary. A broad zone of distributed deformation resulted from the transmission of compressive stresses from the collision at the Pyrenean border. This distributed, intraplate deformation, can be easily related to the topographic pattern of the Africa-Eurasia interface at the longitude of the Iberian Peninsula. Shortening in the Rif-Betics external zones-and their related topographic features-must be conversely related to more "local " driven mechanisms, the westward displacement of the "exotic " Alboran domain, other than N-S convergence. The remaining NNW-SSE to NW-SE, latest Miocene up to Present convergence is also being accommodated in this zone straddling Iberia and Morocco, at the same time as a new ill-de ned plate boundary that is being developed between Europe and Africa.

Research paper thumbnail of Integrated gravity and topography analysis in analog models: Intraplate deformation in Iberia

Tectonics, 2012

Trends in the topography of the Iberian Peninsula show a pronounced contrast. In the western part... more Trends in the topography of the Iberian Peninsula show a pronounced contrast. In the western part of the Iberian microplate the main topographic highs trend E‐W to NE‐SW and are periodically spaced with wavelengths of 250 km. Conversely, in the northeastern part, the region of the Iberian Chain, topography is more irregular and strike directions vary from NW‐SE to E‐W and NE‐SW. We relate this phenomenon to shortening of a continental lithosphere, which contains two different, well‐defined domains of lithospheric strength. Our hypothesis is supported by physical analog models. A new processing method has been developed to assist the interpretation of the model results. It utilizes spectral analysis of gravity and topography data derived from the experiments. Folding of the crust and mantle lithosphere yields periodic gravity fluctuations, while thickening processes lead to localized gravity lows. In this way gravity data can be used to distinguish between the two forms of lithospher...

Research paper thumbnail of The role of lithospheric heterogeneities in the location of the Cenozoic intraplate deformation of Iberia from finite element modeling

Tectonics, 2012

The Cenozoic evolution of the Central System basement uplift and of the continental Duero and Mad... more The Cenozoic evolution of the Central System basement uplift and of the continental Duero and Madrid basins on the Iberian Peninsula occurred in a compressive context triggered by the Alpine orogeny. Although several models of deformation have been suggested, the factors that led to the development of these have not been analyzed to date. We present here finite element modeling of the intraplate deformation of the Iberian lithosphere during the Cenozoic. This modeling has taken into account the role played by (1) the tectonic shortening originating from the Pyrenean and Betic collisions, (2) the weight of Tertiary continental sediments, and (3) thermomechanical heterogeneities present in the lithosphere. The numerical model represents a lithospheric section, with a creep-type mechanical behavior, perpendicular to the Central System, and the two sedimentary basins. Both initial conditions and the results obtained have been specified based on the available geophysical and geological data. This study has enabled us to simulate the present lithospheric structure of the central Iberian peninsula: (a) the formation of the Central System relief and its horizontal shortening, (b) the basement folding in the Duero and Madrid basins, (c) the development of the root of the mountain range, and (d) the depth of the lithosphere-asthenosphere border in the interior of Iberia. The deformations occurred through a large-scale folding and thickening mechanism, by the shortening of a lithosphere that was initially thinner, and with lateral contrasts in temperatures and composition.

Research paper thumbnail of The recent (upper Miocene to Quaternary) and present tectonic stress distributions in the Iberian Peninsula

Tectonics, 2000

A general synthesis of the recent and present stress situation and evolution in the Iberian Penin... more A general synthesis of the recent and present stress situation and evolution in the Iberian Peninsula was obtained from microstructural and seismological analysis. The stress evolution was deduced from (1) fault population analysis (FPA) from 409 sites distributed throughout the Iberian Peninsula, (2) paleostress indicators given by 324 stations taken from the bibliography, and (3) seismic data corresponding to 161 focal mechanisms evenly spread in the studied region. The application of FPA together with the determination of stress tensors and focal mechanisms for the whole Iberian microplate has provided two main results: (1) the Iberian Peninsula is undergoing a NW‐SE oriented compression, except for the northeastern part (Pyrenees, Ebro Basin, and Iberian Chain), where it is N‐S to NE‐SW, and the Gulf of Cádiz, where it seems to be E‐W, and (2) the main trends of the stress field have remained almost constant since the upper Miocene. The analysis performed by zones suggests the p...

Research paper thumbnail of Microdeformation of lacustrine laminite sequences from Late Miocene formations of SE Spain: an interpretation of loop bedding

Sedimentology, 1998

Lacustrine laminated sediments (laminites) present in Late Miocene formations of the Híjar Basin,... more Lacustrine laminated sediments (laminites) present in Late Miocene formations of the Híjar Basin, SE Spain, display well developed loop bedding, a structure consisting of bundles of laminae that are sharply constricted at intervals, giving a morphology of loops or links of a chain. The laminite sequences, which are interbedded with turbidite marlstones, were accumulated on the bottom of a permanently stratified lake developed in a rapidly subsiding basin limited by 010° and 105° normal faults. As deduced from both macro‐ and microdeformational analyses, the basin evolved under an extensional stress field throughout the Late Miocene. Four main types of loops, simple and complex loops with subcategories, have been recognized within the laminite sequence. Simple loops of type 1 show the best definite pattern, quite similar to ‘pinch and swell structures’, a type of boudinage typical of stretching of alternating beds where the competence contrast is not strongly marked. The remaining lo...

Research paper thumbnail of Soft-sediment deformation structures interpreted as seismites in lacustrine sediments of the Prebetic Zone, SE Spain, and their potential use as indicators of earthquake magnitudes during the Late Miocene

Sedimentary Geology, 2000

Lacustrine formations of Late Miocene age in the Prebetic area, SE Spain, show several types of d... more Lacustrine formations of Late Miocene age in the Prebetic area, SE Spain, show several types of deformational structures that are interpreted as seismites. They are present in both marginal and deep lacustrine facies. Seismites formed in marginal lake environments comprise sand dikes, pillows and intruded and fractured gravels. In deep lacustrine facies, the seismites are represented by pseudonodules, mushroom-like silts protruding into laminites, mixed layers, disturbed varved lamination and loop bedding. The measured orientations of these structures are consistent with the orientations of the main faults limiting the basins, showing that their origin is clearly related to the tectonic stress field that prevailed in the region during the Late Miocene. The magnitudes of the earthquakes that deformed the sediments have been estimated after published data from both ancient and recent lake deposits accumulated in tectonic active regions elsewhere. A rank of earthquake magnitudes with two end-members, i.e. the lowest magnitudes recorded by loop bedding in laminites and the highest magnitudes represented by intruded and fractured gravels, is proposed.

Research paper thumbnail of Similarities between recent seismic activity and paleoseismites during the late miocene in the external Betic Chain (Spain): relationship by ‘b’ value and the fractal dimension

Journal of Structural Geology, 2003

A paleoseismic data set derived from the relationship between the thickness of seismites, 'mixed ... more A paleoseismic data set derived from the relationship between the thickness of seismites, 'mixed layers' in lacustrine Miocene deposits and the magnitude of the earthquakes is presented. The relationship between both parameters was calibrated by the threshold of fluidification limits in the interval of magnitude 5 and 5.5. The mixed layers (deformational sediment structures due to seismic activity) were observed in varved sediments from three Neogene lacustrine basins near Hellín (Albacete, Spain), El Cenajo, Elche de la Sierra and Híjar, and are interpreted as liquefaction features due to seismic phenomena. These paleoseismic structures were dated (relative values) by measurements of cyclic annual sedimentation in the varved sediments. From these observations, we are able to establish a recurrence interval of 130 years with events for magnitude bigger than or equal to four. Both paleoseismicity and instrumental seismicity data sets obey the Gutenberg-Richter law and the 'b' value is close to 0.86. The fractal dimension (dimension of capacity) of spatial distribution of potentially active faults (faults oriented according to the stress tensor regime in the area) was measured by the box-counting technique (D 0 = 1.73). According to the Aki empirical relation (D 0 = 2b) for the instrumental seismicity and paleoseismic data sets in the area, the fractal dimension is close to 1.72. The similar value of the fractal dimension obtained by both techniques shows homogeneous seismic dynamics during the studied time interval. Moreover, the better established 'b' value of the paleoseismic data sets (0.86) compared with the 'b' value for the incomplete historic seismicity (<0.5) in the area increases the seismic series beyond the historic seismic record.

Research paper thumbnail of Quantification of fluvial incision in the Duero Basin (NW Iberia) from longitudinal profile analysis and terrestrial cosmogenic nuclide concentrations

Research paper thumbnail of Using river long profiles and geomorphic indices to evaluate the geomorphological signature of continental scale drainage capture, Duero basin (NW Iberia)

Geomorphology, 2014

ABSTRACT Well-constrained case studies of transient landscape responses are needed to improve our... more ABSTRACT Well-constrained case studies of transient landscape responses are needed to improve our understanding of erosion processes associated with drainage captures. The Duero basin is an excellent location for such a study because the landscape is currently undergoing pronounced geomorphological changes resulting from the opening of a former closed drainage. The present-day continental interior basin (&amp;gt; 50,000 km2) drains to the Atlantic Ocean via the Duero River, but during the Cenozoic the basin experienced a long endorheic period marked by the formation of evaporites. Currently, the entire continental interior is an area of relative tectonic quiescence, characterised by a relict low-relief upland topography (Meseta). Systematic variations in lithology and a well-constrained tectonic setting throughout the basin and adjacent areas allow for the comparison of channel morphology between the Cenozoic Duero basin and its western fringe. To explore the signal of transient geomorphic response to capture and opening of the former endorheic basin, the main channel and 24 tributaries were analysed in terms of their longitudinal profiles and the application of geomorphic indices (concavity index [Ci], valley floor width-to-height ratio [Vf], and stream-length gradient index [SL]). The analysis reveals two zones with distinctive morphologies: (1) an upper reach domain consisting of broad flat valleys and low-gradient streams where concave longitudinal profiles dominate and (2) a middle reach domain characterised by steep, deeply incised canyons where a convex long profile dominates marking a major kinckzone. The quantitative information on channel shapes and long profile geometries allows the interpretation of these patterns in terms of driving forces for fluvial landscape development. Large-scale morphometric analysis highlights the transient response of the entire basin to a capture-related base level lowering and illustrates the importance of drainage captures as potential internal drivers of landscape modification and topographic adjustments. Furthermore, the Duero basin case study also emphasises that well-constrained bedrock geology and tectonic patterns are essential to avoid misinterpretation of geomorphic indexes.