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)

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

Single-grain OSL dating of the Middle Palaeolithic site of Galería de las Estatuas, Atapuerca (Burgos, Spain)

This study presents single-grain optically stimulated luminescence (OSL) chronologies for the archaeological site of Galería de las Estatuas – the first systematically excavated Middle Palaeolithic site within the karst system of the Sierra de Atapuerca archaeological complex, northern Spain. The single-grain OSL ages are compared with paired single-grain thermally transferred OSL (TT-OSL) dating results for a selection of samples in order to better assess quartz signal bleaching characteristics of endokarstic deposits preserved at Atapuerca. In total, seven luminescence dating samples were collected from four lithostratigraphic units exposed in two excavation pits (GE-I and GE-II). The single-grain OSL equivalent dose (De) distributions are characterised by generally low overdispersion (20–30%), suggesting appropriate bleaching at deposition. The resultant single-grain OSL ages reveal that the sediment sequence and archaeological remains excavated in pit GE-I accumulated 80–112 ka, while the upper layers of excavation area GE-II were deposited 70–79 ka. The replicate single-grain TT-OSL ages are in agreement with the OSL chronologies at 2σ for three of the four samples investigated; although in all cases the TT-OSL ages were systematically older than their single-grain counterparts. Apparent TT-OSL residual doses (i.e., TT-OSL De values in excess of their corresponding OSL De values) of 9–65 Gy were observed for all samples. These excess TT-OSL De values are generally low in comparison to the natural dose ranges of TT-OSL dating applications undertaken elsewhere in the Atapuerca karst system. The single-grain TT-OSL and OSL dating comparisons build on daylight bleaching experiments and modern analogue studies performed on other Atapuerca exogeneous infill deposits and suggest reasonable potential for TT-OSL signal resetting down to relatively low levels for at least some sediments preserved in the Atapuerca karstic cavities. The quartz single-grain OSL chronologies obtained in this study place the Middle Palaeolithic sequence of Galería de las Estatuas within marine isotope stage (MIS) 5 and the beginning of MIS 4, and provide firm evidence for human occupation of the Sierra de Atapuerca during a previously unreported time period

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

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

Tracer test in the vadose zone of Praileaitz Cave (Deba, Guipúzcoa). Application for protection of karstic cavities

Se ha realizado un ensayo de trazador en la zona no saturada de la Cueva de Praileaitz (Bajo Deba, Guipúzcoa) para ayudar a la delimitación del área de protección de la cavidad. Dicho ensayo se ha efectuado con 14.000 L de agua desionizada y una masa de 500 gr de LiCl. El trazador analizado (Li+) ha permitido deducir un tránsito de entre 18 y 19 horas desde el momento de la inyección. Esta primera detección corresponde a una ve locidad de flujo no saturado de entre 4-5 m/h. La concentración máxima al canzada de litio fue de 11’28 µg/L.A tracer test has been performed in the vadose zone of the Cave of Praileaitz (Bajo Deba, Guipúzcoa) for helping in the delimitation of its protection area.The test was done with 14.000 L of deionized water and a mass of 500 gr of LiCl. The detection of the tracer substance (Li+) has allowed deducing a transit time between 18 and 19 hours since the injection. This first detection corresponds to a non-saturated flow between 4-5 m/h. The maximum lithium concentration was 11’28 µg/L

Reconstructing the sedimentary history of Lezetxiki II cave (Basque Country, northern Iberian Peninsula) using micromorphological analysis

Micromorphological analysis is an invaluable research tool for reconstructing detailed depositional and post-depositional processes of cave infill sequences and for providing paleoenvironmental insight. In this work, we present the results of a micromorphological and mineralogical study of the sedimentary sequence at the Lezetxiki II cave (northern Iberian Peninsula). The cave forms part of the Lezetxiki archaeological complex which has yielded early Middle Palaeolithic tools and archaic human remains. We have identified three main clastic sedimentary processes as being significant at Lezetxiki II: 1) fluviokarst or runoff processes, which are characterised by yellow sandy illite-rich microfacies; 2) infiltration processes, which produce a massive red silty-clay vermiculite-rich microfacies; and 3) inwash processes, which generate a reworked illite and vermiculite rich silty sand microfacies. The most common post-depositional processes observed are calcite precipitation infilling pore spaces, and compression structures derived from specific vertical loading events. In order to improve the chronological framework of the sedimentary sequence at Lezetxiki II, we have revised previous radiometric and relative dating results from faunal and archaeological remains and have dated the lowermost stratigraphic level using single-grain thermally-transferred optically-stimulated luminescence dating. Sedimentation at the Lezetxiki II cave started during Marine Isotope Stage (MIS) 7 through fluviokarst processes. We interpreted that runoff prevailed during MIS 6, while soil infiltration processes became more significant towards the MIS 5 optimum. Gradually, inwash processes prevailed over infiltration until the end of the interglacial phase. During the following glacial phases, runoff and erosion dominated but were subsequently replaced by inwash processes during MIS 1.PALEOGATE project, funded by the Spanish Ministry of Economy and Competitiveness (HAR2014-53536-P) as well as the US14/16 project funded by the University of the Basque Country and Basque Coast Geopark, and Basque Government (IT1029-16-GBV6). We would also like to thank Tim Nicholson for his work in translating and editing different versions of the English text. Additional financial support for this research was provided by Australian Research Council (ARC) Future Fellowship project FT130100195, ARC Discovery Early Career Researcher Award DE16010074

Characterization of complex groundwater flows in the environment of singular buildings by combining hydrogeological and non-destructive geophysical (ground-penetrating radar) techniques: Punta Begona Galleries (Getxo, Spain)

[EN] Locating and quantifying groundwater flow in many built-up areas are a priority with regard to its complete restoration. In this work, a hydrogeological survey of the surroundings of the Punta Begona Galleries (Getxo, Bizkaia), built on a coastal cliff, was completed by using ground penetrating radar (GPR) testing. Thus, the preliminary characterization of soils and rocks in accessible areas of the cliff was first improved by hydrogeological information gathered from a single survey borehole, including permeability measurements by low pressure injection tests (LPTs) and continuous water level monitoring. As a complementary method, the non-destructive GPR technique was performed during both dry and wet hydrological periods and in tandem with the injection tests, providing more complete spatial and temporal images of water flows. Specifically, GPR allows mapping of flow paths in soils and assessing the continuity of fractures in rock masses. Altogether, this complementary approach provides greater knowledge of complex underground flow dynamics in built environments, thus making it easier to make decisions for their managementCity Council of Getxo, Grant/Award Number: OTRI2016-0738; University of the Basque CountryUriarte, JA.; Damas Molla, L.; Sagarna, M.; Aranburu, A.; García García, F.; Antiguedad, I.; Morales, T. (2020). Characterization of complex groundwater flows in the environment of singular buildings by combining hydrogeological and non-destructive geophysical (ground-penetrating radar) techniques: Punta Begona Galleries (Getxo, Spain). Hydrological Processes. 34(4):1004-1015. https://doi.org/10.1002/hyp.13635S1004101534

Metakin bolkanikoen ohiko osagaiak, ehundurak eta egiturak

Arroka bolkaniko eta bolkanoklastikoek osagai, ehundura eta egitura bereziak izaten dituzte, hauen artean daude fenokristalak eta ehundura porfirikoa, kristalak eta kristalen zatiak, bakuoloak, beira bolkanikoa, desbeiratze-egiturak, perlitak, pumita eta eskoria, eta abar. Ezaugarri horiek ez dira diagnostikoak izaten sorrera--prozesua definitzeko orduan, ezaugarri bat baino gehiagoren konbinazioak ematen baitu sorrera-prozesuaren berri. Artikulu honen helburua da osagai, ehundura eta egitura horiek aztertzea