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

Construction and ornamental stones are important elements of cultural heritage and identity and shape the urban landscape of the territories (Pereira & Cárdenes Van den Eynde, 2019). These stones and their quarries are a part of geoheritage that is gaining interest in the tourism industry (Mateos et al., 2011). Red Ereño is an urgonian limestone (Lower Cretaceous) with abundant rudist fossil shells, which white colours highlight on an intense red micritic matrix. This stone is exploited since Roman times in the north of the Iberian Peninsula (Basque Country, Spain). This lithology is found in many buildings, both heritage and common. Its uniqueness has contributed to its expansion worldwide and, it can be found in such emblematic places as the Colon Theatre in Buenos Aires (Argentina) or St Peter´s basilica in the Vatican (Italy) (Damas Mollá et al., 2021).

The main quarry related to Red Ereño is called Cantera Gorria (meaning Red Quarry) and is located inside the Urdaibai Biosphere Reserve (x: 529,659.29 m; y: 4,800,839.60 m; z: 15 m). It is included in the Geosites Inventory of the Basque Country (LIG nº 15), and is part of the historical heritage of the Biscay province. The last concessionaire of the quarry was Marmolería Bilbaína and it ceased its activity in 1968. At present the quarry is abandoned.  Nevertheless, on its exploitation fronts outstanding geologic features are recognised: stratigraphic (bioconstructions, facies changes), petrologic (diagenesis, mineralisations), tectonic (succession verticality, faults) or geomorphologic (karst). All of them make Cantera Gorria a point of reference for both research and teaching activities. Additionally, it is important to underline the richness related to the mining heritage itself. Numerous buildings from the mining activity are still preserved. Also noteworthy are the signs engraved on the rock showing the progress of exploitation in various stages, from manual to the use of helical steel wire.

In the case of Red Ereño and Cantera Gorria the symbiosis between geoheritage and cultural heritage is significant. This symbiosis, together with all the above mentioned characteristics of the quarry makes Cantera Gorria an interesting space for dissemination of geoheritage as well as for tourism (Damas Mollá, 2011).

References

• Damas Mollá, L. (2011): Las Calizas rojas de Ereño: facies, paleoambiente, mineralización y diagénesis. Patrimonio geológico-histórico de Bizkaia. PhD Thesis, University of the Basque Country.
• Damas Mollá L., Uriarte J.A., Zabaleta A., Aranburu A., García Garmilla F., Sagarna M, Bodego A., Clemente J.A., Morales T. & Antigüedad I. (2021). Red Ereño: an ornamental and construction limestone of international significance from Basque Country (northern Spain). Geoheritage 13:2. https://doi.org/10.1007/s12371-020-00529-5
• Mateos R.M, Durán, J.R & Robledo P.A. (2011). Marès Quarries on the Majorcan Coast (Spain) as Geological Heritage Sites. Geoheritage 3: 41-54. http://doi.org/10.1007/sl12371-010-0026-5
• Pereira D. & Cárdenes Van den Eynde V. (2019). Heritage Stones and Geoheritage. Geoheritage 11: 1-2. http://doi.org/10.1007/s12371-019-00350-9