Radon concentration in caves as a proxy for tectonic activity in the cantabrian mountains (Spain)

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

The soft X-ray and narrow-line emission of Mrk573 on kiloparcec scales

We present a study of the circumnuclear region of the nearby Seyfert galaxy Mrk573 using Chandra, XMM-Newton and HST data. The X-ray morphology shows a biconical region extending up to 12 arcsecs (4 kpc) in projection from the nucleus. A strong correlation between the X-rays and the highly ionized gas seen in the [O III] image is reported. Moreover, we have studied the line intensities detected with the RGS/XMM-Newton and used them to fit the low resolution EPIC/XMM-Newton and ACIS/Chandra spectra. The RGS spectrum is dominated by emission lines of C VI, O VII, O VIII, Fe XVII, and Ne IX, among others. A good fit is obtained using these emission lines found in the RGS spectrum as a template for Chandra spectra of the nucleus and extended emission. The photoionization model Cloudy provides a reasonable fit for both the nuclear region and the cone-like structures. For the nucleus the emission is modelled using two phases: a high ionization [log(U)=1.23] and a low ionization [log(U)=0.13]. For the high ionization phase the transmitted and reflected component are in a ratio 1:2, whereas for the low ionization the reflected component dominates. For the extended emission, we successfully reproduced the emission with two phases. The first phase shows a higher ionization parameter for the NW (log(U)=0.9) than for the SE cone (log(U)=0.3). The second phase shows a low ionization parameter (log(U)=-3) and is rather uniform for NW and SE cones. In addition, the nuclear optical/infrared SED has been modeled by a clumpy torus model. The torus bolometric luminosity agrees with the AGN luminosity inferred from the observed hard X-ray spectrum. The optical depth along the line of sight derived from the SED fit indicates a high neutral column density in agreement with the classification of the nucleus as a Compton-thick AGN.Comment: 15 pages, 14 figures, final version of the paper submitted to Ap

Proyecto COSINES: abordando el reto de relacionar fenómenos meteorológicos costeros y retroceso de acantilados en Asturias

[ES] La costa es un entorno muy sensible a los cambios ambientales y climáticos, respondiendo rápidamente a ellos. El escenario actual de calentamiento global predice un ascenso del nivel del mar y un incremento en la intensidad y frecuencia de los temporales, por lo que es esperable una intensificación del oleaje y de la actividad geomorfológica costera. Por ello, en las costas acantiladas se prevé un incremento de las inestabilidades de ladera, considerados el proceso más importante de retroceso costero. Asturias es una región con 660 km de línea de costa, de los que, más de la mitad corresponden a acantilados donde son frecuentes las inestabilidades de ladera. Por otra parte, los municipios costeros presentan además de la exposición al riesgo, una gran vulnerabilidad social y económica debido a su elevada densidad de población, numerosas infraestructuras, actividad industrial y patrimonio cultural. Teniendo en cuenta lo anterior, se ha puesto en marcha el proyecto de investigación “INEStabilidad de laderas como indicador del retroceso de la COSta cantábrica: caracterización multidisciplinar, COSINES”, financiado en la Convocatoria 2017 de Proyectos RETOS de Investigación de la Agencia Estatal de Investigación. El proyecto pretende caracterizar cualitativa y cuantitativamente el retroceso de la costa asturiana utilizando como indicador las inestabilidades en acantilados. Sus objetivos específicos son: 1) establecer la distribución espacial de movimientos de ladera en los acantilados; 2) determinar su tipología; 3) establecer el papel de sus factores condicionantes (litología y estructura geológica) y desencadenantes (fenómenos meteorológicos); 4) elaborar modelos conceptuales de su funcionamiento; 5) establecer su evolución en términos espaciales y temporales; y 6) cuantificar su contribución al retroceso de la línea costera.S

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

Preliminary Hydrogeological Investigations for Sustainable Development in the Courel Mountains UNESCO Global Geopark (NW Spain)

Congreso realizado en Málaga en junio de 2022.[EN] Karst aquifers and, especially, their caves and springs, are singular sites of the geoheritage due to their scientific, touristic and use (water resources) values. Besides, they are recognized as habitats of special protection by the Habitat Directive (92/43/CEE) and would be used for sustainable development in UNESCO Global Geoparks (UGGp). However, their management continues to be a challenge at the present day since karst aquifers and their associated springs and caves are vulnerable environments used by many actors and affected by land uses and changes in surface hydrology and groundwater. Our work aims to implement of a suitable management of aquifers and springs in the Courel Mountains UGGp based on hydrogeological studies. The studies include mainly the characterization of aquifers’ functioning, the elaboration of the spring inventory, physicochemical analyses and geoconservation actions.This work is funded by the Courel Mountains UGGp and the project IGCP-730 Hydrogeological significance of Mediterranean geoparks, and supported by the International Geosciences Program of UNESCO.Peer reviewe

A multi-method approach for speleogenetic research on alpine karst caves. Torca La Texa shaft, Picos de Europa (Spain)

© 2015 Elsevier B.V. Speleogenetic research on alpine caves has advanced significantly during the last decades. These investigations require techniques from different geoscience disciplines that must be adapted to the methodological constraints of working in deep caves. The Picos de Europa mountains are one of the most important alpine karsts, including 14% of the World's Deepest Caves (caves with more than 1km depth). A speleogenetic research is currently being developed in selected caves in these mountains; one of them, named Torca La Texa shaft, is the main goal of this article. For this purpose, we have proposed both an optimized multi-method approach for speleogenetic research in alpine caves, and a speleogenetic model of the Torca La Texa shaft. The methodology includes: cave surveying, dye-tracing, cave geometry analyses, cave geomorphological mapping, Uranium series dating (234U/230Th) and geomorphological, structural and stratigraphical studies of the cave surroundings. The SpeleoDisc method was employed to establish the structural control of the cavity. Torca La Texa (2653m length, 215m depth) is an alpine cave formed by two cave levels, vadose canyons and shafts, soutirage conduits, and gravity-modified passages. The cave was formed prior to the Middle Pleistocene and its development was controlled by the drop of the base level, producing the development of the two cave levels. Coevally to the cave levels formation, soutirage conduits originated connecting phreatic and epiphreatic conduits and vadose canyons and shafts were formed. Most of the shafts were created before the local glacial maximum (43-45ka) and only two cave passages are related to dolines developed in recent times. The cave development is strongly related to the structure, locating the cave in the core of a gentle fold with the conduits' geometry and orientation controlled by the bedding and five families of joints.This research has been funded through the GEOCAVE project (MAGRAMA-OAPN, 580/12, Organismo Autónomo de Parques Nacionales, 2012–2015) and a fellowship granted to D. Ballesteros by the Severo Ochoa Program (FICYT, Asturias Regional Government, BP10-119).Peer Reviewe

Delineating protection areas for caves using contamination vulnerability mapping techniques: the case of Herrerías Cave, Asturias, Spain

Diverse approaches are adopted for cave protection. One approach is delineating protection areas with regard to their vulnerability to contamination. This paper reports the main results obtained from the delineation of a protection zone for Herrerı´as Cave, declared of Cultural Interest by the Asturias Regional Government, based on assessing its vulnerability to contamination. The cave is situated in a complex karst hydrogeologic environment in which groundwater flows from southwest to northeast, following the bedrock structure. A stream flows inside the cave, emerging in a spring located to the northeast of the system. Karst recharge occurs by direct infiltration of rainfall over limestone outcrops, concentrated infiltration of surface runoff in the watershed draining the cave, and deferred infiltration of water from alluvial beds drained by influent streams. The soil and vegetation covers are natural in the majority of the test site, but land uses in the watershed, including scattered farming, stock breeding, quarrying, and tourist use, are changing the natural characteristics and increasing the cave’s vulnerability to contamination. The procedure followed for delineating protection zones is based on the method COP+K that is specifically designed for vulnerability mapping of groundwater springs in carbonate aquifers. To cover the hydrological basin included in the cave’s catchment area, the protection zones established includes two different areas, the hydrogeological catchment basin and adjacent land that contributes runoff. Different degrees of protection in the zones have been proposed to make human activity compatible with conservation of the cave, and our results show remarkable differences from the protection zone previously proposed for the same areaCentro de Hidrogeología, Universidad de Málaga, EspañaDepartamento de Geología, Universidad de Málaga, EspañaDepartamento de Geología, Universidad de Oviedo, EspañaUnidad de Oviedo, Instituto Geológico y Minero de España, Españ

La divulgación científica con audiovisuales como acción de transferencia de proyectos de investigación: el ejemplo de las cuevas del Parque Nacional de los Picos de Europa

X Congreso Geológico de España, 5-7 Julio 2021, Vitoria - GasteizLa difusión de contenidos científicos mediante audiovisuales alojados en plataformas online y redes sociales facilita el acceso público a información usualmente restringida a la comunidad científica. Este trabajo muestra la experiencia obtenida a partir de la creación de un audiovisual para divulgar los resultados de un proyecto de investigación. El proyecto, titulado ¿Caracterización geomorfológica y geocronológica de cavidades kársticas en el Parque Nacional de los Picos de Europa¿ (referencia 580/12, MAGRAMA-OAPN), incluía en su plan de difusión la realización de contribuciones científicas y diversas acciones de transferencia (Jiménez-Sánchez et al., 2019). Entre estas últimas destaca el audiovisual titulado ¿Las cuevas del Parque Nacional de los Picos de Europa: una historia por descubrir¿ (https://goo.gl/wNnQnG), que explica el origen de las cavidades de los Picos de Europa contextualizado en la evolución del relieve del parque. El audiovisual facilita el acceso público al conocimiento científico garantizando, además, el rigor y exactitud de la información divulgada.Dissemination of scientific results through videos shared via online platforms and social media enables public access to information usually restricted to the scientific community. Here we present the experience obtained with the creation of a video for disseminating the results of a research project. The project, entitled “Geomorphological and geochronological characterization of karstic cavities in the Picos de Europa National Park” (reference 580/12, MAGRAMA-OAPN), included in its dissemination plan the making of scientific contributions and several transfer actions (Jiménez-Sánchez et al., 2019), being the video “Las cuevas del Parque Nacional de los Picos de Europa: una historia por descubrir” (https://goo.gl/wNnQnG) one of these actions. The video explains the origin of Picos de Europa caves in the context of the evolution of the park’s relief. This video allows the lay public accessing to scientific knowledge, while ensuring rigorous and accurate information