Evaluation of diagenetic effects upon 87Sr/86Sr ratio in rudist and Chondrodonta sp. shells from Upper Aptian – Lower Albian red limestones of Ereño (Bizkaia)

87Sr/86Sr isotopic ratios measured on rudist and Chondrodonta sp. shells from upper Aptian – lower Albian red limestones of Ereño (Bizkaia) reveal different degrees of diagenetic alteration when compared to coeval values. Chondrodonta sp. and requienid shells show a better degree of chemical preservation, whereas caprotinid and monopleurid shells seem to be more affected by diagenetic fluids. The same conclusion can be obtained when 87Sr/86Sr values are plotted against cationic contents in Sr, Na, Mg, Fe and M

Diagenetic alteration in monopleurid rudist shells from the Urgonian Complex of Ereño (Aptian - Lower Albian, Bizkaia)

Cathodoluminescence and microprobe analysis in monopleurid shells from Aptian – Lower Albian limestones in Ereño (Bizkaia) has allowed to us to realize that different rudist shells show different diagenetic responses in front of a similar degree of diagenetic alteration. Monopleurid shells show a relatively high diagenetic degree when compared to that of requienids. Early neomorphism processes were dissimilar for different shells. The relatively thin monopleurid prisms could allow a diagenetic alteration in a higher degree than that affected requienid shell

Hydric vulnerability of the Gulf of Biscay: from the trends of the recent past to those of the future

Para adaptarnos a los efectos del cambio climático en los sistemas hídricos hay que conocer la dinámica hidrológica del territorio, por lo que nos planteamos dos preguntas: ¿de dónde venimos?, ¿hacia dónde vamos? Para responder a la primera se han considerado las series históricas de caudal de 117 estaciones del Golfo de Bizkaia. Los resultados indican que en los últimos 60 años se ha dado una evidente tendencia descendente en los caudales en todas las épocas del año y un aumento de la duración y severidad del periodo de aguas bajas. Esto refleja una notable homogeneidad espacio-temporal en la evolución de los caudales. En los últimos 20 años ha habido un cambio de escenario, mientras otoño y verano mantienen una tendencia descendente, la de invierno y primavera son ascendentes. Esto refleja una heterogeneidad temporal de evolución de los caudales, que indica un periodo de cambios en el régimen hidrológico. Para responder a la segunda se han simulado regímenes hidrológicos futuros en dos subcuencas. Los resultados indican que el caudal descenderá progresivamente hasta 2100, así como un aumento en la duración y severidad de los periodos de caudales bajos. Otoño será la estación más afectada (18 - 33%) e invierno la menos (-4 - 14%)In order to adapt to the effects of climate change on water systems, it is necessary to know the hydrological dynamics of the territory, so we ask ourselves two questions: where do we come from?, where are we going? In order to answer the first question, we have considered the historical discharge series from 117 gauging stations in the Gulf of Biscay. The results indicate that in the last 60 years there has been an evident downward trend in average discharge and an increase in the duration and severity of the low flow period during all seasons of the year. This reflects a notable spatial-temporal homogeneity in the evolution of flows. However, in the last 20 years, while Autumn and Summer maintain a downward trend for average discharge, during Winter and Spring they increased. This reflects a period of changes in the hydrological regime of this region. In order to respond to the latter question, future hydrological regimes have been simulated in two sub-basins. The results indicate that average discharge will decrease progressively until 2100 and that the duration and severity of low flow periods will increase. Autumn will be the most affected season (-18-33%) and Winter the least (-4-14%

Methodology for assessing the vulnerability of built cultural heritage

The conservation of constructions, and especially of built heritage, requires complex studies concerning their Global Vulnerability. These studies have to consider the current state of the building, i.e. the degradation degree, and the factors that mostly affect the building and, therefore, generate alterations. These factors are not limited to the structure of the building, location and environmental factors are also involved. Hence, the assessment of built heritage vulnerability should consider the building itself and also be extended to the site and the environment. This work presents a systematic and reproducible methodology for the quantification of the Global Vulnerability in different typologies of constructions and environments. The proposed methodology establishes a relationship between the existing alterations (A) and the main factors (F) that affect vulnerability (V) by means of an AFV (Alteration/Factor/Vulnerability) diagram. Based on these results alteration and vulnerability indices are calculated. The obtained AFV diagram allows the comparison between different constructions or separate areas within the same construction. This methodology was validated in two early twentieth-century constructions that form part of the reinforced concrete architectural heritage of the Basque Country: the Punta Begoña Galleries (Getxo, Spain) and the Aqueduct of the Araxes paper mill (Tolosa, Spain).This study was conducted by UPV/EHU Research Group IT-1029/16 (Government of the Basque Country) in the framework of the project titled “Puesta en valor del inmueble histórico cultural Galerías Punta Begoña (Getxo, Bizkaia)” [“Revitalising the Punta Begoña Galleries, a culturally historic building in Getxo, Biscay Province”], under a cooperation agreement between the University of the Basque Country (UPV/EHU) and the City Council of Getxo (OTRI2019-0318). The authors are very grateful for the comments and suggestions of the referees, which have undoubtedly improved the original manuscript

The stones of Begoña Cemetery (Bilbao, Bizkaia)

El Cementerio de Begoña (Bilbao, Bizkaia) fue desmantelado durante el 2022 y se transformará en un parque con “memoria”. Conservará determinados elementos construidos con el objetivo de trasmitir la historia de este lugar a los visitantes. La investigación petrológica sobre las rocas de construcción y ornamentales emplazadas en las sepulturas y panteones ha permitido conocer su uso a lo largo de la historia y su origen y seleccionar los elementos más representativos para su conservación en el futuro parque. Una de las conclusiones del estudio es que el uso de la piedra ha ido variando a lo largo del tiempo. Durante la primera etapa del cementerio (siglo XIX), se utilizaron calizas y areniscas de procedencia local. Durante las últimas etapas (mitad del siglo XX y XXI) se constata la entrada de materiales nacionales e internacionales: calizas, mármoles y rocas plutónicasThe cemetery of Begoña (Bilbao, Bizkaia) was dismantled in 2022 and will be transformed into a park with “memory”. Certain construction elements will be preserved in order to transmit the history of the site to the visitors. The petrological study of the building and ornamental stones emplaced in the graveyards and mausoleums has permitted deciphering their use throughout the history and their origin, as well as selecting the most representative elements for their conservation in the future park. One of the main conclusions is that the use of the stone has changed through the time. During the first phase of the cemetery (19th century), limestones and sandstones of local origin were used. On the contrary, (late half of 20th century and 21st century) limestones, marbles and plutonic rocks of national and/ or international origin were use

Geology and Cultural Heritage workshops in Unesco Las Loras Geopark (Burgos/Palencia)

Relacionar el patrimonio cultural y la geología de un territorio permite acercar a la población esta ciencia, que, en la mayoría de los casos, es menos conocida. En los Geoparques Unesco la interacción con la población y las entidades locales es fundamental para establecer proyectos de desarrollo y conservación, sobre todo en zonas despobladas. Por este motivo las actividades de divulgación son esenciales. Este trabajo presenta dos talleres realizados en dos iglesias, situadas en el Valle de Valdelucio del Geoparque Unesco Las Loras, como ejemplo de divulgación geológica en torno al patrimonio cultural en una zona con alta tasa de despoblación. Este tipo de actividades ofrece a los lugareños y visitantes una perspectiva del entorno novedosa, geológica, que compagina con el patrimonio cultural y realza el valor de la zona.Relating the cultural heritage and the geology of a territory allows the population to get closer to this science, which, in most cases, it is not well known. In Unesco Geoparks, interaction with the population and local entities is essential to establish development and conservation projects, especially in unpopulated areas. For this reason, outreach activities are essential. This work presents two workshops carried out in two churches, located in the Valdelucio Valley of the Unesco Las Loras Geopark, as an example of geological dissemination around cultural heritage in an area with a high rate of depopulation. This type of activity offers locals and visitors a new geological perspective of the environment that combines with the cultural heritage and enhances the value of the are

First data of Cretaceous hydrothermalism in the eastern margin of the Basque-Cantabrian basin

In the Eastern margin of the Basque-Cantabrian Basin, fissures filled with sediments crop out in a red Albian-Cenomanian limestone, near the Txoritokieta mount (Errenteria, Gipuzkoa). In this work we study the sedimentology, petrology and tectosedimentary character of fissures and their fills, in order to establish the evolutive sequence of the formation of fractures and the infill of them. It has been inferred the tectonic origin of the fissures, linked to the synsedimentary folding of the host limestone. Moreover, most of the studied sedimentary fissure fills are mineralized, suggesting that fracturing and fluid flow occurred during the deposition of the fissure fillsEn el margen oriental de la Cuenca Vasco-Cantábrica afloran fisuras rellenas de sedimento encajadas en calizas rojas Albiense-Cenomaniense, en las inmediaciones del monte Txoritokieta (Errenteria, Gipuzkoa). El objetivo de este estudio ha sido estudiar las fracturas y sus rellenos desde el punto de vista sedimentológico, petrológico y tectosedimentario, para establecer la secuencia evolutiva de la formación de las fisuras rellenas. Así, se ha inferido el origen tectónico de las fracturas, ligado al plegamiento sinsedimentario de la propia formación que engloba las calizas encajantes. Asimismo, los rellenos de las fracturas, que se encuentran mineralizados en su gran mayoría, sugieren que su formación (fracturación) se localizó cerca de la superficie de sedimentación y la circulación de fluidos mineralizantes ocurrió en momentos próximos al depósito de los relleno

Geology and built cultural heritage: the transdisciplinary approach in the Punta Begoña Galleries (Getxo, Bizkaia)

En los proyectos de puesta en valor del patrimonio cultural construido la contribución desde la Geología ha de articularse mediante un procedimiento transdisciplinar, que integre los engranajes de las distintas disciplinas y especialidades de nuestra ciencia. Ello permitirá una caracterización que evolucione desde el elemento construido al emplazamiento, integrando ambos en un entorno más amplio que los contextualice y complete. El proyecto de puesta en valor de las Galerías Punta Begoña (Getxo, Bizkaia) es un ejemplo de este enfoque transdisciplinar en el campo de la Geología. La filosofía adoptada permite afrontar las tareas de conservación / recuperación con una visión más global, que resulta más rentable, optimizando los recursos y generando un mayor valor añadido científico, social y culturalIn projects for valuing the built cultural heritage, the contribution from Geology must be implemented through a transdisciplinary procedure that integrates the gears of the different disciplines and fields of our science. This enables a characterisation that evolves from the built element to the site, integrating both in a wider environment that contextualises and complements them. The project of valuing the Punta Begoña Galleries (Getxo, Bizkaia) is an example of this transdisciplinary approach inside Geology. The adopted philosophy allows tackling conservation/recovery tasks with a wider vision, which is more efficient, optimising resources and generating higher scientific, social and cultural benefit

Cantera Gorria and Red Ereño: Natural and Cultural Geoheritage (Basque Country, Spain)

[EN] Construction and ornamental stones are important elements of cultural heritage and geoheritage. The quarries, where these materials are extracted, are a type of site that combines these two types of heritage. Both the ornamental character of the rock and its place of origin can be deeply rooted in the local society. Red Ereno is a red micritic limestone (Lower Cretaceous) with abundant white rudist fossil shells. This stone has been exploited since Roman times in the north of the Iberian Peninsula (Basque Country, Spain) and exported internationally. The main quarry related to the extraction of Red Ereno, Cantera Gorria, is currently a cultural and geoheritage site. This emblematic site brings together numerous geologic (palaeontological, petrological, geomorphological and tectonic) and mining features that make it a reference point for both research and teaching activities. The link between geoheritage and cultural heritage that exists in Cantera Gorria is evident and makes this place an essential point for dissemination of geology as well as for tourism. The quarry is currently abandoned, and because of this, there is an urgent need for its protection and development, and in order to increase awareness of its importance and potential use.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. UPV/EHU Research Group IT-029/16 (Government of the Basque Country)

Why Did Red Ereño Limestone Go Red? Linking Scientific Knowledge and Geoheritage Story-Telling (Basque Country, Spain)

Red Ereño is a red-stained ornamental and construction limestone with characteristic white fossil shells. Although exploited since Roman times, marketed worldwide and that the rock itself and its outcrop areas have been included in geological heritage inventories, the origin of its characteristic reddish colour remained unresolved. The aim of this work is to deepen the scientific knowledge of Red Ereño as a basis for understanding the characteristics of this stone and to make this information available for geoconservation actions. The mineralogical and petrological study, mainly based on optical and electron microscopy, X-ray diffraction, and rock magnetism and paleomagnetic techniques, concluded that the red-staining mineral is pigmentary hematite. Moreover, the analysis stated that hematite precipitated after sedimentation but prior to burial diagenesis and before alpine inversion. Based on palaeomagnetic studies, it can be stated that mineralisation occurred during the Late Cretaceous. This work illustrates how scientific research on this potential heritage stone provides key information for geoconservation.This study has been carried out by the UPV/EHU Research Group IT-1678/22 (Government of the Basque Country) in the framework of the project US21/32 under the cooperation agreement between the University of the Basque Country UPV/EHU, Basque Energy Agency (EVE), and Provincial Council of Biscay (BFA). Authors also thank the support of the project PID2019-108753GB-C21 financed by State Research Agency (Spain) [AEI /https://doi.org/10.13039/501100011033]. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. UPV/EHU Research Group IT-1678/22 (Government of the Basque Country); UPV/EHU, EVE/EEE, DFB/BFA project US21/32