Nyári Cave

Nyári Cave is one of the periodically active water-absorbing caves, located in the Gerecse Mountains within the Danube–Ipoly National Park, in the Gerecse Landscape Protection Area. Deneves also occur in it.

Description

It is situated at the edge of the Gerecse D, in the outskirts of Tatabánya, in a small valley head in the forest on the K–DK part of the Kő Hill plateau, at the bottom of a steep-walled, funnel-shaped sinkhole, with a horizontal, axis-oriented entrance that is 1 m wide and 0.6 m high, broken and irregular in shape. It lies about 150 m D–DK from the Polish Cave and the Polish Chasm, next to a forestry road. The sinkhole is on the upper section of a small water-draining ditch that cuts into the edge of the plateau, at the end of the ditch. The sinkhole has a diameter of 10 m and a depth of 3 m.

The periodically active water-absorbing cave developed in Upper Triassic thick-bedded Dachstein limestone. The cave passage is equipped with basic facilities and is freely walkable.

In 1979 the cave was first called Nyári Cave in the literature. In the literature the cave also appears under the names Polish Cave No. 3 shaft (Polacsek, Ba 2019) and The Polish Cave No. 3 shaft (Székely 1994).

Research history

In the 1961 issue of the Karst and Cave Research Bulletin, a study written by Norbert Bathó includes Nyári Cave according to the manuscript of Ákos Lendvay from 1979. The study publishes that the direction of one blocked passage of the Polish Cave points to the nearby collapsed shaft No. II, which before the discovery of the 8th level was already considered the second entrance shaft of the cave. This hypothesis was also supported by the strong clay blockage that appears on the 8th level, where animal bones were found in the clay.

In the 1979 report of the Kőbányai Barlangkutató és Hegymászó Szakosztály it is stated that near the Lengyel Cave, within a roughly 100 m diameter circle, there are two more caves, the Nyári Cave and the Lengyel Gorge. The Nyári Cave is located about 100 m from the Lengyel Cave at point D, and it is a collapsed, senile sinkhole. Bathó and Lendvay referred to it as the third shaft of the Lengyel Cave. From 1963 to 1964 László Bánkuti excavated it down to 8–10 m depth, to the top of the stalactite formation. In 1965 Ákos Lendvay managed to descend 8 m while moving through a collapse. It is worthwhile to carry out exploratory work in it. According to the manuscript two literary works deal with it.

A map was published in the 1980 MKBT Report that shows a part of the cave survey unit 4630 located in the Gerecse Mountains. On the map prepared by Ákos Lendvay in 1981 the geographical location of the Nyári Cave, marked with number 24, can be seen. In the 1981 first–second half-year issue of Karst and Cave it was made public that the cave survey number of Nyári Cave is 4630/24. In the 1984 book titled *Caves of Hungary*, in the national cave list, the cave with survey number 4630/24 is listed among the caves of the Gerecse Mountains under the name Nyári Cave. Associated with the list, the geographical location of the caves of the Dunazug Mountains is shown on a 1 : 500 000 scale map, indicating the cave’s geographical position. During the cave visit on 11 January 1986, the Vértes László Karst and Cave Research Group determined that there are no bats in it.

According to the 1991 report of the Tatabánya Cave Exploration Association, it is a periodically active water-draining cave. Its water-collecting area is about 1000 m². Its exploration was carried out in the early 1970s by the Vértes László Karst and Cave Exploration Group, and later by the Kőbánya Cave Exploration and Mountaineering Section. At that time they explored it to a depth of about 10 m. Restarting its exploration seems reasonable. About 30 m from the cave, alongside the forestry path, there is a young doline in a developing state, about 1–1.5 m deep.

The study published in the 1994 Limes by Székely Kinga states that the Nyári Cave, catalog number 4630/24, is also known as the Polish Cave III section mine. The cave does not appear in Bertalan Károly’s cave library. The Cave Institute has no cadastral master sheet, map, or literary master sheet for the cave, but it does have a photograph and a research master sheet. During the cave visits on 28 January 2001, 23 June 2001, 23 June 2002, 29 December 2002, 23 February 2003, 25 May 2003, 29 June 2004 and 22 December 2004, the Gerecse Cave Exploration and Nature Protection Association determined that there are no bats in the cave.

In 2005 Zsolt Polacsek surveyed the cave and, based on the survey, drew the cave floor plan map, longitudinal section map and cross‑section map. During the cave visits on 22 January 2006, 30 June 2006, 24 September 2006 and 23 December 2006, the Gerecse Cave Exploration and Nature Protection Association determined that there are no bats in it. According to the association’s 2007 report, the cave was already known in the 1970s. At that time the investigations allegedly reached a depth of 8–10 m, but this figure is unlikely in light of the 2007 exploration results. Its depth could have been at most 5 m based on the nature of the fill.

At the end of 2007 the members of the association began exploratory work in the cave. They cleared and slightly widened the collapsed entrance and began deepening the floor of the then 0.5–1 m wide, 5 m long, 3 m deep and steeply sloping crawl passage in full section. The passage, which gradually widens to 3 m width downwards, was extended to a length of 8.5 m and a depth of 6 m. The excavated material was carried to the surface.

For further exploration it is encouraging that in this cave the airflow conditions are opposite to those observed in the Lengyel Cave – Lengyel Gorge – March Cave system, because here strong ventilation can be observed in winter. There was no data on the cave’s former bat habitation, therefore it is interesting that on 7 October 2007 the presence of two small long‑eared bats was observed near the endpoint. The bats probably used the cave as a seasonal roost.