Suchergebnisse

We present a new crustal-scale transect of the eastern Basque-Cantabrian Zone, through the Cinco Villas Massif, the Leiza-Aralar Thrust System and the South-Pyrenean Zone. The restoration of this transect to its pre-shortening stage allows us to assess the architecture of the hyperextended domain and the style of the Alpine contractional deformation. During the Cretaceous, extension led to a hyperthinned crust with local mantle unroofing to the base of the eastern Basque-Cantabrian Basin. The mantle unroofing process was driven by a complex system of detachments putting into contact Mesozoic sediments in the hanging wall with mantle rocks in the footwall. At this stage, extensive fluid circulation caused serpentinization of the uppermost mantle body. Furthermore, the thermal anomaly created during the unroofing caused high temperature metamorphism of the overlying sediments of the Leiza detachment system and hydrothermalism in further basins. The Alpine convergence gave rise to the tectonic inversion of the Mesozoic basins. Tectonic structures inherited from the Cretaceous hyperextension played a major role in mountain building. The southward indentation of the European crust forced the northwards subduction of the Iberian crust and the basement-cover decoupling along the Triassic evaporites. Restoration of this section to the end of the extensional period enabled us to estimate a shortening of~90 km. ; En este trabajo se presenta un nuevo modelo de estructura cortical en el borde oriental de la Zona Vasco-Cantábrica, atravesando el Macizo de Cinco Villas, el sistema de cabalgamientos de Leiza-Aralar y la Zona Surpirenaica. La restauración de esta sección al estadio previo a la convergencia alpina permite establecer la arquitectura del dominio cortical hiperextendido Mesozoico y el estilo de la deformación compresiva posterior. Durante el Mesozoico, la deformación extensional asociada a la apertura del Golfo de Vizcaya dio lugar a la formación de dominios de corteza hiperextendida y a la exhumación parcial del manto bajo la Cuenca Vasco-Cantábrica oriental. El proceso de exhumación del manto se produjo por la acción de un complejo sistema de detachments extensionales que pusieron en contacto la cuenca cretácica en el bloque superior con el manto en su bloque inferior. En este estadio, la intensa circulación de fluidos a lo largo de estos detachments causó la serpentinización de la parte superior del cuerpo mantélico. Además, la anomalía térmica creada en este proceso, generó un metamorfismo de alta temperatura que afectó a los materiales mesozoicos localizados inmediatamente sobre el manto exhumado, así como hidrotermalismo en cuencas más alejadas de la aureola metamórfica. La orogenia Alpina dio lugar a la inversión de las cuencas mesozoicas, y las estructuras tectónicas heredadas de la etapa de hiperextensión cortical jugaron un papel determinante en la configuración de la estructura orogénica. La indentación hacia el sur de la corteza Europea en la corteza Ibérica forzó la subducción de esta última hacia el norte y el desacoplamiento del basamento con respecto a la cobertera sedimentaria mesozoico-terciaria a lo largo del nivel de despegue de las evaporitas del Triásico superior. La restauración de esta sección cortical al final del periodo extensional indica un acortamiento cenozoico de aproximadamente 90 km. ; We thank the PhD financial support for IDF given by the University of Oviedo-Banco Santander, Government of the Principality of Asturias and the FPU grant of the Spanish Ministry of Education. This is a contribution of the ESF TopoEurope Project PYRTEC (SV-PA-10-03-IP2- PYRTEC), the Consolider-Ingenio 2010 Project TOPOIBERIA (CSD2006-00041) and the Ministry of Economy and Competitiveness Project MISTERIOS (CGL2013-48601-C2-2-R). ; Peer reviewed

The presence of ophicalcites in serpentinized peridotites together with fragments of these rocks in Cretaceous breccias along several North‐Pyrenean basins led to the interpretation of complete mantle exhumation to the seafloor. The westernmost outcrop of peridotites in the Pyrenean‐Cantabrian belt is located in Ziga (eastern Basque‐Cantabrian Basin), associated to a band of HT metamorphism related to the Leiza fault (Marble Unit). We present a petrological and geochemical study of the marbles and Ziga peridotite‐hosted calcite, including standard stable isotope composition and clumped isotope geothermometry. These isotopic techniques allow the determination of different types of formational fluids and crystallization temperatures, and are a useful tool for studying carbonation processes in hyperextended basins. Fieldwork and analytical studies lead us to conclude that during the opening of the Bay of Biscay, mantle rocks were unroofed at the base of the sedimentary pile of the eastern Basque‐Cantabrian Basin. However, the ophicalcite veins were recrystallized from meteoric fluids at low temperatures (≤49°C). The primary carbonate phase may have been formed either during the mid‐Cretaceous unroofing of the mantle or in a post‐exhumation stage. The process of mantle exhumation was accompanied with HT‐LP metamorphism and fluid circulation along major faults that reset the marine isotopic signature in the nearest marbles. For comparison, ophicalcites from Urdach and Lherz (North‐Pyrenean Zone) were included in the clumped isotope study. Results show that they were recrystallized from hot (∼200–230°C), saline fluids, and from meteoric fluids at near ambient temperatures (∼32–42°C), respectively. ; We thank the PhD financial support for IDF, given by the University of Oviedo‐Banco Santander, Government of the Principality of Asturias and the FPU grant of the Spanish Ministry of Education, Culture and Sport. This is a contribution of the Ministry of Economy and Competitiveness Project MISTERIOS (CGL2013‐48601‐C2‐2‐R), the Consolider‐Ingenio 2010 Project TOPO‐IBERIA (CSD2006‐00041), and the ESF TopoEurope Project PYRTEC (SV‐PA‐10‐03‐IP2‐PYRTEC). ; Peer reviewed

Radon (Rn) constitutes a good geochemical tracer for neotectonic activity in faults since associated fracturing near the surface favours fluid escape to the atmosphere. In this contribution, we measured the Rn concentration in the air inside karst caves to constraints the recent fault activity in the Cantabrian Mountains (N Spain). Rock formations exhumed during the uplifting of the Cantabrian Mountains record a long history of fracturing, which has the potential to connect deeper sources of Rn with the surface. In this regional study, we correlate Rn measurements with cave survey data and geological structures using a Geographic Information Systems. Thirty-four Rn average concentration was recorded by CR-39 detectors during 8 integrated months. The method is applied to the central part of the Cantabrian Mountains that is built on sedimentary and low-grade metamorphic rocks relatively poor in U. Dominant tectonic structures and Rn concentration are examined in 28 cavities. The concentration of Rn values is higher than 0.5 kBq·m-3 in caves developed preferably following fractures with the direction N30oW, being the concentration greater than 0.8 kBq·m-3 in cavities located less than 200±50 m from subvertical faults with such orientation. Rn anomalies point to relative high connectivity along subvertical fault zones NW-trending, preserving fracture connectivity in the most recent structures in the Cantabrian Mountains. Finally, in the study area there is a low but significant radioactive hazard which is associated to fault zones in a fractured rock massif. It contrasts with other active tectonic settings where the radioactive hazard may come from fault movements. ; This work is a contribution of the GEOCANTABRICA research group at the University of Oviedo, funded by a grant (GRUPIN14-044) from the Asturian Regional Government (Spain) and FEDER funds. ; Peer reviewed

The critical zone (CZ) represents the most-shallow subsurface, where the bio-, hydro-, and geospheres interact with anthropogenic activity. To characterize the thickness and lateral variations of the CZ, here we focus on the Eastern Betic Shear Zone (EBSZ), one of the most tectonically active regions in the Iberian Peninsula. Within the EBSZ, the Guadalentín Depression is a highly populated area with intensive agricultural activity, where the characterization of the CZ would provide valuable assets for land use management and seismic hazard assessments. To achieve this, we have conducted an interdisciplinary geophysical study along the eastern border of the Guadalentín Depression to characterize the CZ and the architecture of the shallow subsurface. The datasets used include Electrical Resistivity Tomography (ERT), first-arrival travel time seismic tomography, and multichannel analysis of surface waves (MASW). The geophysical datasets combined help to constrain the high-resolution structure of the subsurface and image active fault systems along four transects. The resulting geophysical models have allowed us to interpret the first ~150 m of the subsurface and has revealed: (i) the variable thickness of the CZ; (ii) the CZ relationship between the fault zone and topographic slope; and (iii) the differences in CZ thickness associated with the geological units. Our results provide a method for studying the shallow subsurface of active faults, complementing previous geological models based on paleo-seismological trenches, and can be used to improve the CZ assessment of tectonically active regions. ; The authors would like to thank the following: The project INTERGEO (CGL2013-47412-C2-1-P) GEO3BCN-CSIC for providing access to the data. SeisDARE provides public access to the seismic data [86]. The KEMDIKBUDRISTEK of the Republic of Indonesia for providing a Ph.D. scholarship to the first author. The GIPP-GFZ (Germany) and Lisbon University (Portugal) provided the instrumentation. Additionally, we sincerely thank Seismic Unix CWP (Center for Wave Phenomena, Colorado School of Mines) for allowing us to use the free academic license software, and we also thank everyone who was directly or indirectly involved in this work. J.A. is funded by grant IJC2018-036074-I and by MCIN/AEI /10.13039/501100011033. I.P. is funded by the Spanish Government and the Universidad de Salamanca (Beatriz Galindo grant BEGAL 18/00090). This project was funded by Grant 2017SGR1022 (GREG) from the Generalitat de Catalunya (AGAUR); EU (H2020) 871121 (EPOS-SP); and EIT-RawMaterias 17024 from the European Institute of Technology (EIT) (SIT4ME). ; Peer reviewed

Systematic Review Registration: https://digital.csic.es/handle/10261/193580 ; The immense advances in computer power achieved in the last decades have had a significant impact in Earth science, providing valuable research outputs that allow the simulation of complex natural processes and systems, and generating improved forecasts. The development and implementation of innovative geoscientific software is currently evolving towards a sustainable and efficient development by integrating models of different aspects of the Earth system. This will set the foundation for a future digital twin of the Earth. The codification and update of this software require great effort from research groups and therefore, it needs to be preserved for its reuse by future generations of geoscientists. Here, we report on Geo-Soft-CoRe, a Geoscientific Software & Code Repository, hosted at the archive DIGITAL.CSIC. This is an open source, multidisciplinary and multiscale collection of software and code developed to analyze different aspects of the Earth system, encompassing tools to: 1) analyze climate variability; 2) assess hazards, and 3) characterize the structure and dynamics of the solid Earth. Due to the broad range of applications of these software packages, this collection is useful not only for basic research in Earth science, but also for applied research and educational purposes, reducing the gap between the geosciences and the society. By providing each software and code with a permanent identifier (DOI), we ensure its self-sustainability and accomplish the FAIR (Findable, Accessible, Interoperable and Reusable) principles. Therefore, we aim for a more transparent science, transferring knowledge in an easier way to the geoscience community, and encouraging an integrated use of computational infrastructure. Systematic Review Registration: https://digital.csic.es/handle/10261/193580 ; This research has been funded by the Projects EPOS IP 676564, EPOS SP 871121, SERA 730900, GeoCAM (PGC2018-095154-B-I00, Spanish Government) and the Center of Excellence for Exascale in Solid Earth (ChEESE) under the Grant Agreement 823844. IDF was funded by a FEDER-Junta de Castilla y León Postdoctoral contract (SA0084P20). JA and M-GL are funded by the Spanish Ministry of Science and Innovation through the Juan de la Cierva fellowship (IJC 2018-036074-I and IJC 2018-036826-I, respectively), funded by MCIN/AEI /10.13039/501100011033. AH is grateful for his Ramón y Cajal contract (RYC 2020-029253-I). Additional funding was provided by the Spanish Ministry of Science and Innovation (RTI 2018-095594-B-I00, PGC 2018-095154-B-100) and the Generalitat de Catalunya (AGAUR, 2017SGR1022). AP's work was supported by: a Science Foundation Ireland Career Development Award (17/CDA/4695); an investigator award (16/IA/4520); a Marine Research Programme funded by the Irish Government, co-financed by the European Regional Development Fund (Grant-Aid Agreement No. PBA/CC/18/01); European Union's Horizon 2020 research and innovation programme InnoVar under grant agreement No 818144; SFI Centre for Research Training in Foundations of Data Science 18/CRT/6049, and SFI Research Centre awards I-Form 16/RC/3872 and Insight 12/RC/2289_P2. AH and SG thank the Spanish research project PaleoModes (CGL2016-75281-C2-1-R) which provided some of their financial support. JF is supported by an Atracción de Talento senior fellowship (2018-T1/AMB/11493) funded by Comunidad Autonoma de Madrid (Spain), and a project funded by the Spanish Ministry of Science and Innovation (PID2020-114854GB-C22). ; Peer reviewed