Villuercas

Código Recurso: 6

Tipo: Recurso Natural

Territorio: España

Visitas: The Puerto Llano of Cañamero lies between the towns of Cañamero and Guadalupe. Access is easy from the EX-102 secondary road as far as its junction with the EX-116 secondary road. The fault is situated under a thick layer of colluvium of the Sierra de Belén, where Armorican quartzites that have been intensely crushed in a wide and deep millonitic band can be observed.

Accesibilidad: As the area to be visited is very near the road and on a bend, it is very dangerous to remain on that side of the road or its verge. It is recommendable to make observations from the opposite verge off the road.

Descripción:

This great tectonic fault orientated perpendicular to the folding was formed by the Alpine Orogeny of the mid Tertiary era, and determined the subsidence of the extensive depression situated south of Las Villuercas that is now occupied by the Vegas Altas del Guadiana. A huge tectonic lake ("Lago Sereniano") formed in this depression; it filled with clayey sediments during the Miocene and finally in the Pliocene was completed with the alluvial material of Las Rañas.

Interpretación geológica: Recognising the fault with all its associated elements, together with the millonitic area in the Armorican quartzites and their covering layer of colluvium. The trace, width, and depth of this fault cannot have been taken into account during the project of the old railway line that was to run from Villanueva de la Serena to Talavera de la Reina, which has now been abandoned. A long tunnel of 1363 m was planned that would cross the fractured Armorican quartzites of the Sierra de Belén from east to west at Puerto Llano on the eastern flank of the wide Ruecas Syncline. The greatest drawback of this route was the rugged relief and the hardness of the quartzite rocks of the Sierra, together with the crushed and millonitic area of this great fault. This prompted the decision to abandon definitively all work on the line, as the Puerto Llano tunnel was affected by several dangerous landslides because it was hard to brace it given the methods of the time. These setbacks justified the total abandonment of the railway project by a Ministerial Order of 22nd September 1962