Szende Cave

The Szende Cave is one of the periodically active water-draining caves located in the Gerecse Mountains within the Danube–Ipoly National Park. Deneves also occur in its passages.

Description

It opens on the upper section of the Farkas Valley on the eastern side of Halyagos Hill, 113° and 3300 m from the village church in the outskirts of Vérteszőlős. Directly next to the busy tourist trail marked with a red stripe, it has an artificial and vertically oriented entrance on the east side. Its entrance, closed with a grate and developed, is rectangular in shape.

The Szende Cave is situated between the László Cave of Vértes and the Arany Hole of Szőlősi. It is about 70 m from the Szőlősi Arany Hole and 330 m at 45° from the László Cave of Vértes. On tourist maps it is marked with a cave symbol together with the indication of its name.

The upper 6 m of its entrance shaft is reinforced with concrete well rings. The lower part, with a diameter of 1–1.5 m, is divided by small steps and reaches the deepest point of the cave at a depth of 12 m. The periodically active water-draining cave was formed in thick-bedded Dachstein limestone of the Upper Triassic. Its rock contains many tectonic fractures. The two main fracture directions are ENE–WSW and ENE–SSW. The formation of its central shaft was determined by the corrosion of infiltrating waters, but in its side passage erosional forms indicating former water flow are decisive. During rainy periods the inflowing water appears in the lower section of the cave, and at that time it also backs up at the end point. It can be visited with the permission of the Danube–Ipoly National Park Directorate.

The temperature of its air varies between 5.5–9 °C. On average 7.3 °C. The Gerecse Cave Research and Nature Conservation Association carried out bat observations in Szende Cave, during which they determined the presence of 2 bat species; the lesser mouse‑eared bat and the common bat among the group members. Based on the observation data and the occasionally found fresh droppings, it can be considered an occasional winter bat roost with a small number of species and individuals.

In 1978 the cave was first called Szende Cave in the literature. The cave also appears in the literature under the names 31st water‑drinker (Juhász 1978), 31st water‑drinker (Juhász 1978), 31st water‑drinker (Juhász 1994), 31st water‑drinker (Székely 1994) and Gerecse 31st water‑drinker (Polacsek 1991).

Research history

In the summer camp of 1978 the Vértes László Karst and Cave Research Group explored the cave. On the last day of the camp they led about 2000 l of water here, which had become redundant. To their surprise they observed that the introduced water did not even reach the deepest point of the shaft, but disappeared on its steep side. After this they performed trial drilling. In the 1.5 × 2 m section they started a research shaft that, due to large rock blocks, narrowed unevenly and at 5 m reached a free cave passage. The narrow corridor descending in the collapse, after 2 m, was already bounded by stalactites and opened into a room about 2 × 5 m. It seemed that from here one could proceed in two directions. They tried to enlarge the narrow part with a section expansion, but the risk of collapse forced them to cease the work.

Exploration can only be continued after appropriate safety conditions are created (minimum 3×2 m section, secured research shaft). According to the 1978 group report, the entrance they considered insignificant was not listed in their register until 1978. Because of the previous results, the group re‑evaluated the site map made by the group in 1969 and therefore the water sink numbered 31 on the site map, the Szende Cave, was not shown on the site map. The members wanted to name the caves discovered near the Snow‑White Cave after the seven dwarfs. The suggested names were Hapci, Morgó and Szende. Attached to the report was a 1:10 000 scale site map on which the location of the Halyagos Mountain caves and water sinks can be seen. The location of the Szende Cave is marked on the site map. In the 1978 MKBT Report the printed version of the report saw the light of day.

In 1979 the group’s 54 members worked here ten times for a total of 320 hours. They enlarged and secured the unstable entrance shaft. They reached a free passage at a depth of 6 m. At the beginning of the flat corridor, about 10 m long, rock debris was present, further inside sand‑clay had accumulated. Dripstones can also be seen on the ceiling. It was planned to establish a permanent workplace here in 1980. According to the 1979 report of the secretary‑general of the Hungarian Karst and Cave Research Society, the Kőbánya Cave Research and Mountaineering Department planned to carry out exploratory research in the cave.

In 1980 the Vértes László Karst and Cave Research Group, with 98 members, worked twenty times for a total of 470 hours on the exploration of the cave. The passage segment discovered in 1979 was examined in detail. The 12 m long part, only crawlable because of the fill, is closed at both ends by debris. Due to the danger of collapse it is impossible to break through it. Erosional forms can be observed on the walls. Water‑flow channels have been cut into the surface of the fill. All signs indicated that a large amount of water once flowed here. After observing the flow directions they decided to further open the western inlet of the entrance shaft. After deepening the inlet by about 0.5 m they encountered an unexpected obstacle. Under the previously humus‑rich and rock‑debris fill they found a very hard material. They passed through this layer about 2 m thick, after which another air‑filled passage followed. The new section, about 4–5 m long, leads under the southern debris of the chamber. Here it is already possible to attempt further progress safely from a passage bounded by stalactites.

On 15 June 1980 Juhász Márton and G. Kis made a sketch survey of the cave. Based on the survey Juhász Márton prepared a 1:100 scale plan map with five cross‑section maps. Together with the post‑survey exploration, the cave is about 25 m long, with a plan length of 19 m, horizontal extent of 13 m, vertical extent of about 11 m and about 11 m deep. Its floor area is about 30 m² and its volume about 55 m³. The depth was measured from the ground level next to the entrance shaft. The cave map and a report on the cave research appeared in the 1980 MKBT Report.