Névtelen Sinkhole

The Névtelen-sinkhole is one of the periodically active characteristic water‑draining caves located in the Gerecse Mountains of the Danube–Ipoly National Park. Denevérek also occur in its passages.

Description

It is on the upper section of the Farkas Valley on the eastern side of Halyagos Hill in the outskirts of Vértesszőlős, with an entrance closed by a steel‑plate door equipped with a hole opening from the bottom of a pit and leading inward. It is situated beside the busy tourist trail marked with a red stripe, at the vertical axial artificial entrance. About 30 m east‑north‑east from the entrance of the Szőlősi Golden‑hole is its entrance.

The upper 5.5 m of the entrance shaft is built with concrete‑brick masonry. The very corroded‑walled shaft, in its lower third briefly splitting into two branches, is 0.6–1.5 m in diameter and 18.5 m deep, leading to the Kurtős‑room which is 2–4.5 m wide, 8 m long and 0.8–1.2 m high. The room’s ceiling arches up to 2–2.5 m at the central opening, a 9.7 m high vault.

At the upper end of the room a passage 1.2–1.8 m wide, 4.5 m long and 0.6–0.8 m high connects, which continues with a winding, small‑step‑divided crawlspace leading to an 8 m deep fissure shaft. Another fissure shaft, beginning at the lower end of the room and narrowing to a finish, is 12 m deep.

The periodically active water‑draining cave formed along the complex fracture system of thick‑bedded Triassic Dachstein limestone mainly due to the corrosive action of infiltrating waters, although erosion also played a significant role in its enlargement. Beautiful stalactites formed in the Kurtős‑room. The lower parts of the cave are always moist. It can be visited with the permission of the Danube–Ipoly National Park Directorate.

The temperature of its air is lower than average, in the Kürtős chamber it varies between 4–8 °C. The annual average is 6.7 °C. The Gerecse Barlankutató és Természetvédő Egyesület carried out bat observations in the Névtelen-nyelő, during which they recorded the presence of four bat species; small bent-winged bat, long-eared bat, common bat and brown long-eared bat among the group members. Based on the observation data and the occasionally found fresh droppings, it can be considered an occasional winter and conditionally summer bat roost with a small number of species and individuals.

In 1977 the cave was first called Névtelen-nyelő in the literature. The cave appears in the literature as 19.sz. viznyelő (Juhász 1978), 19. sz. víznyelő (Székely 1994), 19.sz. víznyelő (Juhász 2007), Felsö Aranylyuk (Polacsek 1989), gerecsei 18.sz. nyelö (Polacsek 1989), Gerecsei 18. számú víznyelő (Polacsek 1991), H - 12 A (Polacsek 1989), Névtelen-barlang (Lendvay 1980), Névtelen-nyelö (Polacsek 1989), Névtelen nyelő (Lendvay 1978) and Névtelen-nyelők (Lendvay 1977).

Research history

In 1977 the Kőbányai Barlangkutató és Hegymászó Szakosztály extracted 1500 buckets of sediment from the Névtelen-nyelő (from the Névtelen-nyelő) without result and built a surface filter gallery. In 1978 the department struggled a lot with the Szőlősi Arany-lyuk entrance and the Névtelen nyelő. The cave opening beside the path had to be protected from curious hikers, therefore it was fenced.

During the spring camp Csapi Dezső, Farkas Béla and their companions removed 5–6 m³ of material from the steep-walled sinkhole located 30 m from the Szőlősi Arany-hole. At the end of the camp it was clearly visible that they would reach a 15–18 m deep, walkable but collapsing inclined fissure. However, because of the rains after the camp, the inadequately secured and too steeply angled pit almost completely collapsed.

According to the 1978 report of the Vértes László Karst and Cave Research Group, the group re‑evaluated the site map prepared by the group in 1969 because of the then‑existing results and therefore the 19th water sink is a collapse‑filled shaft. Attached to the report was a 1:10 000 scale site map showing the location of the caves and water sinks of Halyagos‑hegy. The site map marks the location of the water sink numbered. The printed version of the report appeared in the 1978 MKBT Report.

In 1979 the Cave Research and Mountaineering Department of Kőbánya led by Csapi Dezső carried out extensive work at the sink and entered the free cave passage, which was explored to a depth of 8 m and a length of 13 m. The endpoint was blocked by a stone, but the sound of falling rocks could be heard clearly for about 10–12 m. The department’s 1979 report states that, by researching the system consisting of the Szőlősi Arany-hole, the Hófehérke cave and the Névtelen sinks (whose connection was demonstrated by the department in 1976), the department expects the discovery of the largest caves of Gerecse.

The system probably merges above the Vértes László Cave and its passages are presumed to be at least as large, or in a fortunate case larger, than the often mentioned size of the Vértes László Cave due to its high chambers. It is also not unimaginable that the merged cave branches lead to the endpoint of the Vértes László Cave, under the Siphon chamber. In this case it would be the largest and deepest cave of Gerecse. The Szőlősi Golden-hole system still includes 2 unexplored water inlets, but it may be connected with as many as 4–5 inlets. Attached to the report is a black‑white photograph on which the Anonymous sinkhole belonging to the Szőlősi Golden-hole system can be seen.

In 1980 the department finished the exploration of the Anonymous cave due to the great collapse danger and the cave research was taken over by the Vértes László Karst and Cave Research Group. In that year Ákos Lendvay, Tibor Somorjai, László Takács and László Bukor surveyed it. According to the 1980 MKBT Programme Booklet, the sinkhole located about 30 m from the Szőlősi Golden-hole was split by two cave‑research groups. A black‑white photograph can be seen in the department’s 1980 report, showing the excavated Anonymous cave.