Gossans, Slates, and the Red and Black Hamlets of Segovia (Spain): Interrelated Geological and Architectural Features

An Erratum to this article was published on 19 May 2017

This article has been updated


The Sierra of Ayllón in Central Spain has a rich heritage from both the architectonic and geological perspectives. On one hand, the low lands flanking the northern side of the sierra in the Segovia Province host the so-called red hamlets and black hamlets (pueblos rojos-pueblos negros). The red and black terms derive from the traditional local building materials: Miocene red gossan breccias and Ordovician-Silurian black slates, respectively. Although these hamlets have a series of undeniable esthetic and historical values, it is the geology of this realm which accounts for most of the remarkable features in the studied zone. In this regard, near the hamlet of Madriguera, there are outstanding, unique outcrops of Miocene gossan deposits and deeply hydrothermally altered Silurian slates, forming what we have here defined as the “Madriguera Gossan Corridor” geosite. This, together with the intrinsic historical and esthetic values of the red and black hamlets, confers to the area (both at the regional and local scales) an immense scientific, educational, and touristic potential. The formal assessment of this site following the official methodology of the Geological Survey of Spain (IGME) confirms its highly valuable interest as a geosite.

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Change history

  • 19 May 2017

    An erratum to this article has been published.


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This study was partly supported by Grant UCM 910492 (Magmatismo y Mineralizaciones en la Zona Centro-Ibérica Hercínica). Many visits of the authors to the Madriguera outcrops (and elsewhere in the region) were also conducted during BSc and MSc field courses in Geomorphology, Mineralogy and Mineral Deposits (Facultad de Ciencias Geológicas—UCM). The paper benefitted from the comments of E. Díaz-Martínez and an anonymous reviewer.

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Correspondence to Roberto Oyarzun.

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The original version of this article was revised: Figures 4 and 5 were interchanged.

An erratum to this article is available at https://doi.org/10.1007/s12371-017-0233-4.

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Oyarzun, R., Duque, J.F.M., Barrenechea, J.F. et al. Gossans, Slates, and the Red and Black Hamlets of Segovia (Spain): Interrelated Geological and Architectural Features. Geoheritage 10, 109–121 (2018). https://doi.org/10.1007/s12371-017-0229-0

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  • Ayllón Sierra (Spain)
  • Architectural and geological heritage
  • Gossan deposits
  • Hydrothermally altered slates
  • Geosite