Geology

Cuevas de As Adegas

The As Adegas Caves are a unique geological formation found along the course of the River Varón. Their origin is due not only to the interaction between water erosion and rock, as granite is a plutonic rock that is particularly resistant to water erosion. Unlike the caves we usually imagine, with large chambers adorned with stalagmites and stalactites, these caves are small hollows that may be isolated or interconnected.

Within the As Adegas system, there are three types of cavities, distinguished by their formation: fissure caves are generated by the separation of two walls caused by a fracture in the rock; and block caves are formed when large granite blocks detach and accumulate in the valley, leaving voids between them. Their size depends on the magnitude of the fallen fragments. In both cases, seismic activity plays a key role in their evolution. The third type of cave, called tafoni, has an uncertain origin, although it is believed they are formed by granular disintegration inside the blocks. Over time, they create spectacular ceilings with a characteristic concave-convex, honeycomb-like relief.

The combination of these processes has generated a collapsed canyon of blocks up to 30 metres deep, through which the River Varón briefly disappears from view before re-emerging in a waterfall downstream. However, their value goes beyond the geological. Some mineralised remains of fossilised micro-organisms and ceramic artefacts from the Bronze Age have also been found in the caves, demonstrating their anthropological and palaeoecological importance.

Due to the complexity and risks involved in exploring the interior of the cave system, access is restricted to persons with training in speleology who are federated, ensuring safety and accident prevention. However, from the outside visitors can enjoy the impressive waterfall where the river re-emerges, and the imposing stacked granite formations that dominate the area.