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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.

Los expertos han constatado una pérdida de interés hacia la geología de la población en general que podría estar relacionada con su exclusión progresiva en el currículo básico en la educación obligatoria. Sin embargo, es necesario que el alumnado que finaliza la Educación Secundaria Obligatoria (ESO) adquiera una correcta alfabetización en Ciencias de la Tierra, en la que entender los procesos geológicos externos y su acción en el relieve es un contenido clave. Este estudio ha evaluado qué procesos geológicos externos se enseñan en la ESO de la Comunidad Autónoma del País Vasco, mediante el análisis de los libros de texto más utilizados y la realización de cuestionarios al profesorado. Ambas fuentes revelan que el estado actual de su enseñanza muestra deficiencias y necesita mejoras, tales como dedicarle el tiempo y espacio que le corresponde o mejorar la calidad de los textos empleados., Analysis of teaching external geological processes in the compulsory secondary school of the Autonomous Community of the Basque Country Abstract: Experts have noted that the interest of the general population in geology has decreased. This seems to be related to an exclusion of geology from compulsory education curriculum. However, it is mandatory that the students who complete compulsory secondary school acquire a correct literacy in Earth Sciences, in which understanding external geological processes and their action on the relief is a key content. Our study has evaluated which external geological processes are taught in the compulsory secondary school of the Autonomous Community of the Basque Country. To this end, the most commonly used textbooks were analyzed and teachers were asked to fill out questionnaires. Both sources reveal that the current teaching of this unit shows deficiencies and, consequently, needs improvement in both the quality of the texts used and in the time and space devoted to this unit.

[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.

Kontinenteen apurketa luzaroan ikertu den prozesu geologikoa da. Rifting deritzon prozesu horrek milioika urte irauten ditu, eta kontinente-ertzetan, mendikateetan eta bestelako ingurune geologikoetan topatzen dira fenomeno tektoniko horren aztarnak. Plaka tektonikoen banaketaren interpretazioa, ordea, eboluzionatuz doa ikertzaileen ulermenaren eta aurrerapen teknologikoen arabera. Hiperestentsioaren ideia da interpretazio horren azken berrikuntza. Ideia hori litosfera kontinentalaren deformazio polifasikoan barneratzen da, litosferaren muturreko luzapenean oinarrituz, hain zuzen. Ertz egonkorretan eta gerriko orogenikoetan identifikaturiko egitura geologiko eta eremu estruktural bereizgarriek ahalbidetzen dute fenomeno horren bilakaeraren nolakotasuna definitzea. Magman txiroak bezala ezagutzen diren ertz egonkorretako eremu horiek dira hurbileko domeinua, necking domeinua, urruneko domeinua edo hiperluzatua eta kanpoko domeinua. Domeinu horietako bakoitza riftingaren deformazio faseekin lotzen da; fase horiek litosfera kontinentalaren luzapena, mehetzea, mantuaren azaleratzea eta lurrazal ozeanikoaren zabaltzea dira. Esan bezala, iraganean hiperluzatutako arroetan ari da garatzen ikerketa, eta hipotesi horren bitartez ulertzen hasia da, honezkero, Euskokantauriar arroa (EKA) barneratzen duen Iberia eta Eurasia arteko Mesozoikoko rift-sistemaren garapena. Urteetan arroan bildutako datuek, behintzat, horretara bultzatzen dute. Pirinioen mendebaldean deskribaturiko mantuaren azaleratzeak eta arroan deskribaturiko hamaika prozesuk indartu dute Kretazeoko riftingean hiperestentsioak izan zezakeen garrantzia; azken horrek, gainera, garai hartako EKAren eboluzio geologikoaren paradigma argitu dezake.; Continental breakup is a geological process which has been deeply learnt. The keys of that tectonic phenomena, the so-called rifting process that lasts millions of years, can be found worldwide within rifted margins, mountain chains and other geological settings. However, t

Alkerdiko mendigune eta sistema karstikoaren zein Alkerdiko kobazuloaren eta bere babes eremuaren azterketarako proiektuaren barruan, Alkerdi 2 kobazuloaren miaketa burutu da. Ikerketa koordinatuek lurrazalean agerturiko aztarna arkeologikoekin erlazionaturiko labar arte multzo bat identifikatzea ahalbidetu dute. Grabaturiko animalien irudien estiloak Gravette aldiko giza presentzia bat frogatzen dute. Labar irudietako baten zein testuingurutik datorren ikatz baten erradiokarbonozko datazioek hau baieztatuko lukete. Beraz, Nafarroan agerturiko bigarren kobazulo apainduaren aurrean egongo ginateke, eta Foru Erkidegoko adibide artistiko zaharrenen aurrean., Within the framework of the characterization project of the massif and karst system of Alkerdi, the Alkerdi cave and its protective environment, the Alkerdi 2 cavity was explored. The coordinated work has made it possible to identify a set of parietal art associated with archaeological evidence on the surface. The style of the engraved animal points towards a Gravettian attribution for human presence. Radiocarbon dating of one of the parietal motifs and a charcoal from the archaeological context corroborate this idea. This is the second cavity decorated during the Paleolithic in Navarre and the oldest artistic remain in the Autonomous Community., En el marco del proyecto de «Caracterización del macizo y sistema kárstico de Alkerdi, de la cueva de Alkerdi y de su entorno de protección», se procede a la exploración de la cavidad de Alkerdi 2. Las labores coordinadas han permitido identificar un conjunto de arte parietal asociado a evidencias arqueológicas en superficie. El estilo de las grafías animales grabadas apunta hacia una atribución Gravetiense para la presencia humana. La datación por radiocarbono de uno de los motivos parietales y de un carbón procedente del contexto arqueológico, lo corroboran. Se trata así de la segunda cavidad decorada durante el Paleolítico en Navarra y la muestra artística más antigua de la Comunidad Foral.

This paper sets out a methodology for calculating the potential zone of damage to which an Item of Cultural Interest (ICI) located in a karst environment is exposed. An itemised study of the geological characteristics of the cave environment is proposed: lithological cartography, endokarst and exokarst geomorphology and the study of fracturing of the limestone massif. Based on these data and using a Geographical Information System (GIS), it was possible to calculate the degree of the geological threats on a susceptibility map, according to the vulnerability of the heritage item to be protected and its exposure to the identified hazardous geological processes. By combining these parameters, the existing geological risk was calculated and mapped and the necessary protection area for conservation of the cultural heritage was defined. This methodology was applied in the Alkerdi caves located in the municipal area of Urdazubi/Urdax (Navarre, northern Spain).

In this paper we present and discuss Cretaceous extensional folds of the eastern Basque-Cantabrian Basin (Northern Spain). Geometry and kinematics of folds is constrained by means of structural and sedimentological fieldwork integrated with geological mapping, revealing an intimate link between coeval folding, extensional faulting, and salt mobilization. In detail, the Mesozoic succession of the northwestern and southern borders of the Palaeozoic Bortziriak-Cinco Villas massif (eastern margin of the BCB) host late Albian–early Cenomanian syn-rift forced folds. The studied forced fold axes trend parallel and are located above main and inferred Cretaceous syn-sedimentary basement faults. Structural data indicate that these folds formed during the late Albian − early Cenomanian interval. The presence of Upper Triassic clay and evaporite outcrops along and/or close to the axes of folds and their stratigraphic relationship with Upper Cretaceous strata indicate their halokinetic origin and extrusion during folding. The trigger of salt tectonics is attributed to a basement extensional pulse during the Bay of Biscay – Pyrenean rifting. Related high subsidence-rates allowed salt to flow towards faults, forming salt walls and causing the inflation and folding of the overburden.

El sistema kárstico de la Cueva de Nerja se desarrolla en los mármoles dolomíticos del Manto de Almijara. Estos mármoles se presentan semidesnudos, con escaso desarrollo edáfico y abundantes rasgos de meteorización. Se han constatado procesos de meteorización del mármol dolomítico que provocan su brechificación, disgregación y formación de arena dolomítica, así como la formación de distintos depósitos carbonáticos secundarios: calcretas y espeleotemas. La Cueva de Nerja alberga depósitos detríticos, en su mayoría arenosos, cuya composición es dolomítica. El objetivo de este trabajo ha sido caracterizar y relacionar los procesos edáficos exokársticos con los sedimentos detríticos del interior del karst. Así, la arena dolomítica o regolito puede i) pasar a formar parte de los horizontes edáficos, como en la actualidad; ii) quedar embutida en la calcreta; o iii) ser transportada al interior del karst por procesos hídricos y gravitacionales.

The Basque Cantabrian basin has a very long evolutionary history. It started in the early Permian, and the latest evolutionary steps took place in the Miocene. During those 250 My significant changes happened in the dominant tectonic regime (extension, compression), in the distance to the plates limit (rift, passive margin, active margin), and the nature of the underlying continental crust (extended or hyperextended). The Basque Cantabrian basin has a complex evolution, controlled by the dominant tectonic conditions.; Euskokantauriar arroaren eboluzioak oso iraupen luzea du. Goi Permiarrean hasi zen, eta azken prozesuak, Miozenoan gertatu ziren. 250 Ma inguru horietan zehar, aldaketa nabarmenak izan dira bai erregimen tektoniko nagusian (luzapena, konpresioa), bai plaken arteko muga aktiboarekiko distantzian (rifta, ertz pasiboa, ertz aktiboa), eta bai azpiko lurrazalaren izaeran (kontinentala eta hipermehetua). Euskokantauriar arroak, oro har, eboluzio-prozesu konplexua du, baldintza tektoniko nagusiei egokituz pixkanaka aldatu zena.

The Basque Cantabrian basin has a very long evolutionary history. It started in the early Permian, and the latest evolutionary steps took place in the Miocene. During those 250 My significant changes happened in the dominant tectonic regime (extension, compression), in the distance to the plates limit (rift, passive margin, active margin), and the nature of the underlying continental crust (extended or hyperextended). The Basque Cantabrian basin has a complex evolution, controlled by the dominant tectonic conditions.; Euskokantauriar arroaren eboluzioak oso iraupen luzea du. Goi Permiarrean hasi zen, eta azken prozesuak, Miozenoan gertatu ziren. 250 Ma inguru horietan zehar, aldaketa nabarmenak izan dira bai erregimen tektoniko nagusian (luzapena, konpresioa), bai plaken arteko muga aktiboarekiko distantzian (rifta, ertz pasiboa, ertz aktiboa), eta bai azpiko lurrazalaren izaeran (kontinentala eta hipermehetua). Euskokantauriar arroak, oro har, eboluzio-prozesu konplexua du, baldintza tektoniko nagusiei egokituz pixkanaka aldatu zena.