Geoparque Mundial UNESCO

Nº21 – Santa Lucía-Río Ruecas Syncline

Geoparque Villuercas > Nº21 – Santa Lucía-Río Ruecas Syncline

LOCATION AND ACCESS

The Cabañas del Castillo village is an excellent viewpoint from which to observe this syncline and the Appalachian relief of the region. We will observe the geomorphology of the northern part of this great syncline from its western flank, specifically from the Peña Buitrera (vulture nest crag) and the Peña del Castillo (Castillo crag), two steep quartzite peaks that protect the Cabañas de Castillo village.

To ascend to the Peña Buitrera, or to the ruins of the Cabañas castle, we climb from the village itself in the direction of the cemetery following a path that runs southeastwards, along which we reach a pass that separates the two summits. From here, if we continue ascending the steep path towards the north, we will reach the Peña del Castillo and to the south of our position we will have the Peña Buitrera.

ATTRACTIONS OF THE VISIT

During the visit, in addition to the impressive geology of the vertical outcrop of the Armorican Quartzite, on which the Arab castle of Cabañas sits, we can observe to the east the Appalachian-type relief with its typical alignments of mountain ridges. In the surrounding area, there are good examples of deformation structures (folds and faults) and geomorphological structures (such as gorges, cliffs and rock faces). And to the west, the extensive Trujillo-Cáceres peneplain with its beautiful dehesas.

Trace fossils can be found in the area, such as trilobite burrows, called Cruziana, or others in the form of simple tubes, called Skolithos, attributed to animals that dug their vertical galleries in the intertidal zones.

It is a very interesting geosite for bird watching, which use these crests (Peña Buitrera) for nesting, and a good place to see roe deer, deer, ocellated lizards, butterflies and other arthropods. You can also enjoy the oak forests on the shady side and the old cork oaks on the sunny side.

In the rock shelters and caves of the Ruecas valley, the Brazo pass and the Santa Lucía gorge, you can find the best sets of schematic cave paintings in the Villuercas.

GEOLOGICAL INTERPRETATION

Read Geological Interpretation

The Santa Lucía syncline is the second largest syncline in Las Villuercas (after the Guadarranque syncline), and is located at its westernmost end, bordering the Trujillo-Cáceres peneplain. It is several tens of kilometres long, between its periclinal termination to the north of Deleitosa-Miravete and the Puerto Llano in Cañamero, where it is cut by Cenozoic materials, and is no more than three kilometres wide.

Geomorphologically, and following the trend of the Palaeozoic in the area, the Santa Lucía syncline is an example of inverted relief, constituting a “hanging syncline”, i.e. a topographic high with respect to the anticlinal structures that flank it and which have suffered the effects of erosion to a greater extent. This syncline preserves Palaeozoic materials, quartzites, sandstones and shales, with a complete sedimentary sequence of Ordovician age, in which the quartzites are intercalated with shales and sandstones, culminating in the diamictites of the Gualija Formation.

The most prominent rock, as its outcrops are the ones that form the summits, is the Armorican Quartzite. These rocks are very resistant to erosion and have an excellent exposure that allows us to observe the important Variscan tectonic movements that have shaped the folding and recent Alpine fracturing, with a NE-SW orientation, which causes displacements in the strata of the synclinal structure, as well as allowing us to identify the different cliffs that form the alignment of the summits.