Las fallas y pliegues recientes y activos de la parte centro-oriental de las Zonas Internas de la Cordillera Bética

The most recent tectonic structures of the central-eastern Internal Zones of the Betic Cordillera (from 3.1ºW to 1.7ºW and to the south of 37.525ºN) include fault and folds developed from the Late Miocene onwards, which are related to N-S/NW-SE directed continental collision and moderate thickening of a crust that is relatively hot at depth. In this setting, E-W to WSW-ENE folds, with locally associated E-W transpressive right-lateral and reverse faults, favoured the emersion of the northern Alborán basin palaeomargin and the progressive intramontane basin disconnection. The NNE-SSW to NE-SW trending regional left-lateral Palomares and Carboneras fault zones are dominant structures in the easternmost part of the cordillera. In addition, NW-SE to WNWESE trending normal and oblique-slip normal faults are widespread. The collision is still active and continues to drive active folds and faults, some probably being the likely source of moderate-sized earthquakes. The Campo de Dalías and surrounding sectors, deformed by active ENE-WSW folds and NW-SE to WNW-ESE oblique-slip normal faults, are probably the sites with the largest concentration of significant earthquakes during recent years. Moderate-magnitude earthquakes (Mw 5.0 to 6.5) have occurred there at fairly regular intervals, in 1804, 1910, and 1994. Toward the east, NW-SE trending normal faults extending from Almería to the Tabernas basin deform the Quaternary rocks with associated moderate seismicity (the 2002 Gergal Mw 4.7 earthquake, and possibly the 1894 Nacimiento earthquake, felt with intensity VII). In the Sorbas-Vera basin, the Palomares fault zone is also responsible for moderate-sized earthquakes (1518 Vera earthquake). In the Almanzora corridor, NW-SE to WNW-ESE trending Lúcar-Somontín faults also could be considered one of the possible source of moderate-magnitude seismicity (1932 Lúcar, Mw 4.8 earthquake felt with intensity VIII). Toward the east, between Albox and Partaloa, several small reverse faults and associated compressive structures deform Quaternary alluvial and fluvial sediments. Although some of these folds reveal a slow and progressive deformation from the Middle Pleistocene onwards, some of these reverse fault segments that deform the western Huércal-Overa basin could host the 1972 NW Partaloa, mbLg 4.8 earthquake, felt with intensity VII.Las estructuras tectónicas más recientes que deforman la parte centro-oriental de las Zonas Internas de Cordillera Bética (entre 3.1º y 1.7ºO y al sur de 37.525ºN) son fallas y pliegues que comenzaron a formarse aproximadamente en el Mioceno superior en un contexto de colisión continental N-S/NO-SE y moderado engrosamiento cortical. En este marco tectónico, pliegues y fallas transpresivas dextras e inversas de direcciones E-O/OSO-ENE favorecieron la emersión del borde norte de la paleocuenca de Alborán y la progresiva desconexión de pequeñas cuencas intramontañosas. Además, comenzaron a formarse las grandes zonas de falla de Palomares y Carboneras, con direcciones NNE-SSO y NE-SO respectivamente y movimientos sinistros, que también han condicionado la evolución de la Cordillera Bética oriental desde el Mioceno superior. Algunas fallas con salto normal/normal-oblicuo y trazas NO-SE/ONO-ESE también se han desarrollado ampliamente en toda la zona de estudio. La colisión, aún activa, permite que algunos pliegues y fallas continúen propagándose en la actualidad, eventualmente causando terremotos con magnitudes moderadas. El Campo de Dalías y los sectores adyacentes, deformados por pliegues activos de direcciones ENE-OSO y fallas NO-SE/ONOESE normales-oblicuas, probablemente representan la zona con mayor concentración de terremotos importantes (Mw 5.0-6.5) con eventos recurrentes en 1804, 1910 y 1994. Al este del Campo de Dalías, una amplia zona de falla normal se extiende en dirección NO-SE desde Almería hasta la cuenca de Tabernas. Esta zona de falla muestra evidencias de funcionamiento durante el Cuaternario y tiene sismicidad moderada asociada a su terminación septentrional (el terremoto de Gergal en 2002 con Mw 4.7; y posiblemente el terremoto de Nacimiento en 1894 con intensidad VII). La zona de falla de Palomares es también responsable de terremotos moderados en la Cuenca de Sorbas-Vera (terremoto de Vera en 1518). En la parte central del corredor del Almanzora, alguno de los segmentos de falla normal que se extienden entre Lúcar y Somontín podría ser responsable del terremoto de Lúcar, en 1932 (Mw 4.8 e intensidad VIII). Al este, entre Albox y Partaloa, se han descrito fallas inversas y pliegues asociados que deforman sedimentos cuaternarios. Aunque algunas de estas estructuras muestran evidencias de funcionamiento lento y progresivo durante el Cuaternario, el terremoto de Partaloa en 1972 (mbLg 4.8 e intensidad VII) pudo ser causado por la actividad de cualquiera de estos segmentos de falla inversa que deforman la parte occidental de la cuenca de Huércal-Overa

Towards 3D databases and harmonized 3D models at IGME-CSIC

IGME-CSIC has a highly relevant geological and geophysical database that includes a continuous digital geological cartography at 1:50000; 1:200000 and 1:1000000 scales and a fair amount of geophysical data: gravity, magnetic, well-logs in tiff and LAS format, seismic lines in tiff and SEG-Y format, borehole and petrophysical data, together with other geophysical and geological studies. Since the 2004, an important effort has been done to undertake 3D geological and geophysical modelling ranging from local studies (mineral exploration or CO2 storage sites) to regional geology for a better understanding of the subsurface structure and its geodynamic evolution as a base for other studies on natural hazards or mineral resources. These studies were ¿stand alone¿ and now IGME is designing a new strategy. It includes the available data and models harmonization (stratigraphy sequences, structural interpretations, faults distribution, seismic velocity models, spatial distribution of physical properties such as density and magnetic susceptibility, workflows, methodologies, evaluation of uncertainties, visualization, etc.) to comply with the FAIR (Findable, Accessible, Interoperable and Reusable) data standardization. In this way, the new 3D models will be easily integrated and available from the databases. This strategy includes collaboration with the Bureau de Recherches Géologiques et Minières of France (BRGM) and Laboratório Nacional de Energia e Geologia of Portugal (LNEG) in order to harmonize the Spanish geological data and models with their neighbours across national borders. The first step is being done in the framework of GeoERA projects. Plain-language Summary IGME-CSIC owns a large database that includes a highly valuable geological and geophysical data and geophysical studies containing the interpretation of some of the data of Spain (onshore and offshore) Since 2004 the authors of this work have been working in 3D geological and geophysical modelling that includes local (mineral exploration or CO2 storage sites) and regional studies. The goal is to improve our understanding of the subsurface structures and processes as a base for deepening our knowledge in how the natural hazards occur, how to improve the exploration for mineral resources, etc. These studies were made ad hoc within different projects and now IGME-CSIC is designing a workflow to harmonize these models in order to comply with the FAIR (Findable, Accessible, Interoperable and Reusable) data standardization so the models will be available to being used beyond the initial objectives that generated their creation. This strategy includes collaboration with other European institutions like the Bureau de Recherches Géologiques et Minières of France (BRGM) and Laboratório Nacional de Energia e Geologia of Portugal (LNEG) in order to harmonize the models across national borders. The first step is already being done in the framework of the GeoERA projects

Integrating current and historical water chemistry data with long-term piezometric records to develop a regional-scale conceptual flow model: Las Salinas spring, Medina del Campo, Spain

20 p. - Supplementary material related to this article can be found, in the online version, at doi: https://doi.org/10.1016/j.ejrh.2021.100781.[EN] Study region Old Las Salinas spring in Medina del Campo, Duero river basin, central Spain. Study focus Medina del Campo groundwater body (MCGWB) is a multilayer semiconfined aquifer subject to intensive pumping since the 1970’s, where the current existence of spas where there used to be traditional baths could confirm the existence of deep groundwater flow paths. The old spring of Las Salinas (OSLS) is a saline anomaly in an aquifer with predominance of CaCO3H waters whose occurrence has not yet been formally explained. Long-term geological, geophysical, hydrogeological and hydrochemical records were integrated and complemented with field work to clarify its existence. New hydrological insights for the region Outcomes led to the conclusion that the hydrochemistry of the Olmedo and Palacio de las Salinas salt baths is associated with the existence of a major threshold in the impervious basement of the aquifer, which intercepted deep regional groundwater flow and caused upwelling to the surface under unperturbed conditions. These results allow for the development of a conceptual flow model at the regional scale that explains the changes in natural water chemistry that have been identified in recent decades.This research has received funding from the European Union H2020 Programme under Grant Agreement No. 730497 for the research project NAIAD-NAture Insurance value: Assessment and Demonstration.Peer reviewe

Estimation of mining voids volume in the batolith of Linares (Jaen)

In the mining district of Linares (Jaén, Spain) an important underground mining activity has taken place until the first 90's, based on the exploitation of metal sulphides related to a framework of veins within a granite batolith. Actually, the mining have been abandoned, leaving as a result an important number of voids (shafts, galleries and veins excavated). After the closure of the mines, as a consequence of the stopping of the drainage pumping operations, the potentiometric levels have risen and the majority of the artificial voids are currently flooded. It's necesary to quantify the mining voids volume for water reserve evaluation. The stimation of the mining voids has been carried out from digital image analysis of vertical sections planes of the exploitation works. There is a fraction of mines that haven't got vertical sections planes available. In this case, we have estimated the volume of voids from statistical study and linear regression functions, vein longitude versus voids volume. The total amount of voids calculated is 13,1 hm3

The Hinojares synsedimentary fold (Pozo Alcón-Tíscar area, Jaen province, Betic External Zone)

4 páginas, 4 figuras.-- Trabajo presentado en la 41ª Sesión Científica, Barcelona, 2006.In the proximities of Hinojares (northern border of the Guadix-Baza basin), there is a growth syncline, formed in Plio-Quaternary sediments, showing progressive unconformities in its limbs. At its ESE prolongation, the recent glacis, Pleistocene in age, shows two flexions parallel to the fold hinge and limbs. This fold has been probably controlled by the Tiscar fault and formed within a NNE-SSW compressive setting.Este estudio ha sido financiado por los proyectos CGL200401636/BTE, CGL2004-03333/BTE, la Acción Integrada BTE2001-5230-E y el grupo RNM 217 de la Junta de Andalucía.Peer reviewe

Deployment of a local semi-permanent seismic network along the northern Guadiana Menor River area (Betic Cordillera)

Congreso realizado en Toledo del 28 de noviembre al 1 de diciembre de 2022.[EN] In the last decade, the Guadiana Menor River region, in the Guadalquivir foreland Basin, has suffered some low to moderate magnitude seismic sequences. For instance, the 2012-2013 Sabiote-Torreperogil seismic sequence, 1 to 5 km deep, being the biggest recorded event a mbLg 3.9, and the 2016-2018 Jódar-Peal de Becerro seismic sequence, less than 2 km and other events at 9 to 13 km deep, located 20 km southeast of the previous one, being a mbLg 4.1 earthquake the greatest recorded magnitude. In the last years, the Spanish IGN national seismic network has also recorded several low magnitude earthquakes in the region, clearly showing that the fault that hosted the 2016-2018 seismic sequence continues to be active.This has been the reason to deploy a local seismic network in the region, designed with the aim to study this persistent seismicity in terms of both locations and focal mechanism solutions. It is equipped with seven triaxial broadband sensors, also sharing data coming from two nearby IGN seismic stations. Most of them are recording data from September 2021. Real-time records are shared with the Spanish IGN seismic network in order to improve regional locations.Peer reviewe

Déformations néotectoniques dans les dépôts plio-quaternaires de la région de Casablanca-Mohammedia (Meseta côtière, Maroc)

10 páginas, 5 figuras, 1 tabla.-- Trabajo presentado en: The Atlantic Neogene in the XXIth Century: State of The Art.[FR] La bande littorale atlantique de la Meseta marocaine montre dans la région de Casablanca- Mohammedia des dépôts plio-quaternaires qui résultent de plusieurs transgressions marines. Ces formations sont organisées chacune en terrasse marine progradante déposée pendant une période de régression. Ces dépôts marins sont couverts d éolianites qui sont associés aux cordons dunaires plus ou moins parallèles à la côte actuelle. L analyse tectonique de ces dépôts plio-quaternaires révèle que la région d étude, qui était considérée comme étant une zone stable, a enregistré plusieurs déformations cassantes récentes (décrochements, failles normales et diaclases). Il s avère ainsi, que les dépôts plio-quaternaires ont été affectés au moins par deux phases compressives et une phase distensive. Cette tectonique récente peut être liée à la propagation vers l avant-pays de la déformation due à la convergence NW-SE Afrique-Europe et à la progression récente vers le SW du Rif et de son bassin d avant fosse du Saïss-Rharb.[ES] La banda litoral atlántica de la Meseta marroquí septentrional, en la región de Casablanca- Mohammedia, muestra depósitos plio-cuaternarios progradantes como resultado de varias transgresiones marinas. Estos depósitos corresponden a secuencias regresivas y están asociados a terrazas marinas. Las formaciones marinas están recubiertas por depósitos eólicos relacionados con cordones dunares aproximadamente paralelos a la línea de costa. El estudio neotectónico de los depósitos plio-cuaternarios ha permitido precisar la edad de las deformaciones recientes, mostrando que la región estudiada, que había sido considerada como una zona estable, ha registrado varias deformaciones frágiles (fallas normales, desgarres y diaclasas). Estas deformaciones indican que los depósitos plio-cuaternarios han sido afectados al menos por dos fases compresivas y una fase distensiva. La tectónica reciente de la región puede estar ligada a la propagación hacia el antepaís de los esfuerzos asociados a la convergencia NW-SE entre Africa y Europa, y a las deformaciones recientes de vergencia SW del Rif y de la fosa de antepaís de Saïss-Rharb.Ce travail a été financé par la Agencia Española de Cooperación Internacional et la Consejería de Presidencia de la Junta de Andalucía.Peer reviewe

Estructura del Campo de Dalías a partir de datos gravimétricos y sísmicos

The analysis of new gravity data and multichannel seismic profiles of the Campo de Dalías give new insight about the main features of the deep structure. The progressive development since the Tortonian of folds determine the location of a large ENE-WSW elongated depocentre in a synform located at the central area, bordered by two antiforms situated respectively southwards, near the coast line, and northwards, in the Sierra de Gádor. Folding increase at depth and minor folds are also recognised in the limbs of the major folds. The faults in the region have relatively short slips and most of them have not clear expression in the geophysical data

Hydrogeological effects of mining closure. The Linares "general drainage gallery" case

The general drainage gallery of the Linares mining district was designed to minimize elevation cost from dewatering the deepest levels of the underground works. Following the mining closure and the flooding of the mining voids, this gallery (the so-called "socavón") is draining by gravity groundwater resources of the Linares batolith. In addition, an exploitation of these resources is taking place by pumping directly from old shafts, some of them connected through the gallery. The gallery discharge has been monitored during a year as well as the physico-chemical characteristics of the water. The flow averages 60 I/s and both the electrical conductivity and temperature of the water are quite stable. Flow variations suggest a relatively quick response to the infiltration inputs as well as the effect of pumpings. E.C. values point out to an homogeneous process of mineralisation of groundwater, which can be attributed to sulphide oxidation buffered by carbonates. The groundwater balance of the batolith is at present equilibrated. The increasing in pumping is likely to be accompanied by the progressive exhaustion of the gallery flo

Gravimetric anomalies of the Guadix-Baza basin (Betic Cordillera, Spain)

11 páginas, 4 figuras.[EN] Gravimetric anomaly maps (Bouguer and residual) of the Guadix-Baza basin (Betic Cordillera, southern Spain) have been accomplished from the acquisition of 3648 new measurements. The residual anomaly map aims to evidence the features of the shallow crustal structures and clearly show the existence of several important depocentres (particularly that of the Baza sector) controlled by NNW-SSE faults in their eastern and western borders, while the northern borders are limited by the Cadiz-Alicante fault zone (s). The sedimentary facies and the thickness of the filling of the basin are consistent with the position of the depocentres: in the Baza area lacustrine facies are more abundant than in the depocentres of Guadix and Freila-Gorafe. The formation of the depocentres is clearly connected with the ENE extension affecting the whole cordillera.[ES] Se han realizado los mapas gravimétricos de anomalías de Bouguer, regional y residual en la cuenca de Guadix-Baza (Cordillera Bética, sur de España) a partir de 3.648 nuevas estaciones de medida. El mapa de de anomalías residuales pretende ayudar a establecer las estructuras de la parte superior de la corteza y muestra claramente la existencia de varios depocentros importantes, en particular el del sector de Baza, controlados por fallas NNO-SSE en sus bordes orientales y occidentales, mientras que la zona de falla de Cádiz-Alicante los limita por el norte. Las facies sedimentarias y el espesor del relleno de la cuenca son congruentes con la posición de los depocentros: en el sector de Baza abundan en mayor proporción las facies lacustres que en los sectores de Guadix y Freila-Gorafe. La existencia de los depocentros está claramente determinada por la extensión ENE que afecta a la Cordillera.Este trabajo se ha realizado a través de la acción especial BTE2001-5230-E (Geometría del basamento de la cuenca de Guadix-Baza. Cordillera Bética) de la SEPCT.DGI, del Ministerio de Ciencia y Tecnología y de los proyectos CGL200401636/BTE, CGL2004- 03333/BTE, CGL2006-06001, CSD2006-00041 y el grupo RNM 217 de la Junta de Andalucía.Peer reviewe