Nagy-Somlyóhegyi Cave

The Nagy-Somlyóhegyi Cave is located in the Pilis Mountains within the Danube–Ipoly National Park. It is among the specially protected caves of Hungary. Tourist maps mark the geographical location of the cave entrance.

Description

In the outskirts of Pilisjászfalu, on the 4th mining level of the abandoned Nagy-Somlyó stone mine, which is east‑northeast of the settlement centre and at a higher elevation, the cave entrance facing east‑north is situated at 320 m above sea level. Tourist maps mark the location of the cave entrance with a cave symbol and the cave name. The cave entrance is in Pest County, 100 m from the border of Komárom‑Esztergom County.

Bats also occur in the vertical, karstic cave. It is the longest and deepest cave in the Pilisjászfalu area. The sealed cave can be visited with a permit. At most two groups may visit per day. A group may consist of up to six persons. Access is restricted during the bats’ resting period.

In 1994 the cave was first described under the name Nagy-Somlyóhegyi Cave. In literature the cave also appears as Nagy-Somlyó-hegyi-cave (Szabó 2002), Nagysomlyó-hegyi-cave (Juhász, Takácsné 1993) and Nagy Somlyói-cave (Kárpát 1991).

Research History

In the manuscript written by József Kárpát in 1991 it is mentioned that the Nagy Somlyói Cave (Piliscsaba) is 35 m long and 20 m deep. The Erzsébet SC Cave Research Department’s 1993 report states that the Nagy-Somlyóhegyi Cave is mainly explored by the department. In the upper part they climb through shafts, and at the lower end they prepare large excavation work. From Jászfalva east‑northeast, on the former 4th mining level of the abandoned stone mine situated higher than the settlement, at 320 m above sea level, the cave entrance faces east‑north. The entrance is in Pest County, 100 m from the border of Komárom‑Esztergom County. The entrance is a well‑recognizable strong tectonic fissure that dips 80° toward east‑north. Along the fissure a 30°‑inclined karst spring tube about 70 × 120 cm in diameter forms the cave entrance, which was discovered after blasting.

The cave was formed in the tectonic fault that separates the mountain. There is a great chance of exploring a vertical, but probably also horizontally significant, phreatic cave extending down to the karst water level (approx. 150 m). The existence of a larger cave is also supported by the following facts: a 20 m vertical, slightly twisted, shaft with an average size of 2×3 m, showing a marked opening, with a semi‑rocky floor at the bottom, through whose stone‑debris openings small stones dropped continue to roll and bounce. From the endpoint a cave draught flows upward across the full cross‑section at an average speed of 2–3 m/min, which, above the mine shaft over the cave, over the now‑filled opening, during the coldest time melts even the thickest snow over an area of about 6 m².

The cave entrances, the upper one which is filled in, and the lower one which is freely accessible, were discovered in 1978. The author of the report, at 16 years old, was probably among the first to explore it to the bottom. At that time, aragonite crusts of a beauty comparable to the Strázsahegy‑Sátorkőpuszta also adorned some places. In December 1993 members of the department began excavating the upper, near‑surface parts, which succeeded on 12 February 1994. At that time a cracked‑topped chamber of 4×5 m was uncovered, from which a shaft descends vertically downward. This chamber is the highest point of the cave. At the lower collapse point of the cave the most probable further passages are being explored and therefore the members are removing the fill by collapse. Large cave crickets were observed in the cave. Seventeen photographs taken in the cave are attached to the manuscript. The photographs were made on 24×36 cm colour 21‑day film.

The report included the longitudinal section map draft of the cave, prepared by Pál Brusznyiczki, Zoltán Brusznyiczki, Béla Lipták, Zoltán Lipták, György Paul, Gyula Szabó and Iván Wéber, and edited by Gyula Szabó. The map draft marks the locations shown in the photographs. On the section, places marked with a red circle indicate locations that are highly prone to collapse and need to be reinforced with static support structures. The 1993 Karst and Cave publication mentions that the Erzsébet SC Cave Research Department opened an upper small chamber in the Nagy-Somlyóhegy Cave (Pilis Mountains) in 1993 and prepared the removal of the deep‑point debris fill. The department carried out the map and photo documentation of the 22 m deep, water‑filled, trumpet‑shaped cave. The Polygon Cave Research Geological Hydrological Association drew the longitudinal section map of the cave in 1995, reflecting the state of 1995, showing the support walls installed in the cave in 1995.

The association's 1995 report included the cave's longitudinal section map made in 1995 and a surface map at a scale of 1:50,000 depicting the area around the Görényluk cave. The surface map shows the geographical location of the Nagy-Somlyóhegyi Cave indicated on the map. From May 14, 1998, according to Ministerial Decree 13/1998. (V. 6.) KTM, the Nagy-Somlyóhegyi Cave located in the Pilis Mountains within the jurisdiction of the Danube–Ipoly National Park Directorate may be visited with the directorate's permission. The 2002 MKBT Information Bulletin mentions that the Erzsébet SC Cave Research Section received the permit required for research in the Nagy-Somlyó-hegyi Cave on June 1, 1993. The then lower endpoint was 16 m deep in a large rock collapse fissure. In addition to the frequent dismantling and passage‑securing work carried out in 1994, the members, with a separately requested permit, sealed the cave entrance.