Voliotis Sinkhole

The Voliotis sinkhole is located in the Koziakas mountain range at an altitude of 1750 meters. Sinkholes are formed by the erosion created by the flow of groundwater, usually in limestone rocks. The sinkhole is 92 meters deep. It has no decoration, while at the bottom it hosts a small amount of ice. It has a large entrance, measuring 16×7 meters, and also hosts a large colony of birds that find shelter in it. The Volioti sinkhole is located south of the shelter and the peak (Astrapi) of Koziakas, deviating from the paths that cross the Koziakas ridge to the south. Access to the interior requires special equipment and experience in cave descents

This sinkhole is another indication of the intense karstification of the area. The rocks of Koziakas are strongly karstified, resulting in the presence of underground galleries and streams in the interior. Karst erosion starts from the surface and follows tectonic faults and cracks in the interior, gradually dissolving the limestone. In this way, the continuous circulation of groundwater widens these openings, forming underground water conduits that often communicate with each other. The formation of karst structures in the interior of Koziakas is controlled by the alternation of limestone rocks with radiolarites and clay shales. The large to vertical slopes of the limestone rocks on the ridge of Koziakas favor the development of karst structures in height, and the transport of water underground to lower altitudes on the eastern slope. One such formation is the Voliotis sinkhole, an almost vertical karst water transport conduit which has now been revealed on the surface.