Vaskobak Cave

Vaskobak Cave is one of the caves located in the Vértes Mountains in the Danube–Ipoly National Park, in Csákvár.

Description

The cave lies in the outskirts of Csákvár, on the edge of Gánt, in a stone quarry. Its entrance is in the former bauxite extraction of Hosszú-haraszt, situated on the DNy side of Gém Hill. The cave is most easily approached from the D side of Gánt. From the monument, one must walk more than 0.5 km on the DK road leading to the reclaimed bauxite mine, and from there the mine wall’s EN side can be reached only on foot. In front of the mine wall, in the mine yard, a dolomite outcrop a few meters high with a 10 m diameter hematite coating can be observed. On its D side, at 203 m above sea level, the cave’s narrow entrance hole is 0.5 m in relative height.

The cave consists of two adjoining spherical chambers only slightly larger than a meter in diameter. Small side passages connect to these. From the rear chamber a tectonic line leads to a fissure that has opened up, 0.5 m high but only 20–30 cm wide, making it impassable, and its end curves. From the ceiling of the spherical chamber a slightly curved dome extends about 2 m upward, a few decimetres in diameter, reaching almost to the outer surface. Perpendicularly from the southern, elongated chamber, a very narrow passage starts slightly upward, formed by the fusion of small spherical bulges. A characteristic of the whole cave is that water breaking in from below has dissolved its way upward into the rock. Dissolution forms and spherical bulges are visible everywhere on the ceiling.

During the Hajdán bauxite fill, in a place with a compressed water mirror, a cavity formed inside a stone pit, the filling rock is a very fragmented, tectonic breccia-like dolomite that directly formed the bauxite seam. In the cave, the only speleothem formation consists of white calcareous coatings appearing in small spots on the ceiling. It is unknown whether the filling sediment is original or entered after the cavity opened to the surface. Nowadays, during heavy rains a small lake forms at the entrance, whose water sometimes flows into the cave. The wet clayey, silty sediment fills the lower part. Clay deposited from the periodic lake in the cavity creates drying crack polygons. No permit is required to visit the easily accessible cave, which can be traversed by climbing and using basic caving equipment.

In 2005 the cave was first called Vaskobak Cave in the literature. The cave also appears in the literature under the name Gánti külfejtés 6th cave (Futó 2008).

Research history

The Alba Regia Cave Research Group mentions in its 2004–2005 yearbook that during the demolition of the Gánti külfejtés 5th cave the group members looked around the abandoned bauxite mine in Gánt. The research yielded results, because Uncle Frici found a breakable cavity in the side of a separate red rock block near the seed wall. At first they did not pay much attention to it, but Uncle Frici quickly progressed in removing the stones from the cavity, so the others joined the demolition work. Soon the stones were being taken out of the cavity. In the small chamber behind the entrance a person could already fit, therefore the new cavity could be called a cave. On November 12, weekend, four members of the group traveled again to Gánt with appropriate tools. All movable stones were removed from the entrance chamber of Vaskobak Cave, so enough space is now available for further demolition. The stones carried out of the chamber (unlike the external environment) were white dolomitic rocks. The interior of the cavity is also dominated by dolomite.

In the entrance hall a grown adult can fit comfortably, to the right the floor is formed by an inclined clay layer, which gradually narrows as it meets the sloping ceiling. In front (through a narrow passage) one can see a chamber that is larger than the entrance hall. The bottom of the narrow passage can be easily broken through; with about 30 minutes of work one can reach the larger inner chamber. The cave floor has most likely been composed of clay since the end of mining, and water deposition traces are visible on its surface. The cave size appears almost larger than that of the surrounding rock. In several places the cave wall is probably formed only by iron‑pot clay, which is similar to cast iron. The cave was left in the described condition before darkness set in. Further excavation of the cave is recommended; its form features are certainly of interest. The discovered voids should be surveyed after gaining access to the inner chamber.

The cave could have been formed in the following way: after the bedrock sank, the deposition of iron‑oxide bauxite on the dolomitic shales at depth began under tropical weather conditions. The well‑washed, settled bauxite’s iron content concentrated in the lower layers, where, under the influence of iron‑oxide and iron‑hydroxide (with the help of metasomatic mineralisation), an iron‑copper crust formed on the dolomitic shales that constituted the original spatial surface. Over time, part of the dolomite lying beneath the iron‑copper crust was leached out by the massive outflowing water, therefore cavities could have formed under the protection of the iron‑copper. During mining the bauxite lens was removed from the trap created by the sedimentation, completely down to the bedrock. In this case a brown‑reddish, locally black iron‑copper settled on the surface of the dolomite. The mining and weathering probably pierced the wall of the formed cavity, which the group members found and opened. The manuscript contains two colour photographs that show the Vaskobak Cave. In the first photograph the entrance of Vaskobak Cave is visible, with the excavation of Gánti external excavation cave No. 5 in the background above. In the second photograph the entrance of Vaskobak Cave can be seen. The photographs were taken by Gyula Molnár.