Oszolyi Fissure

The Oszolyi fissure is a cave located in the Pilis Mountains within the Danube–Ipoly National Park, situated at Oszoly. It is also described in tourist guidebooks.

Description

In the outskirts of Csobánka, on the third rock group located east of the Oszoly Óra wall, on the DNy side, the cave entrance is at about 5 m height. The entrance of the fissure, easily noticeable from the base of the wall, can be reached by easy climbing. The 6.5 m deep cave was formed in Upper Triassic Dachstein limestone. The cave, consisting of a single vertical fissure, is divided into two parts at about half its height by a rock block. The cave, which can be traversed without equipment, is insignificant for further exploration.

In 1975 the cave was first called Oszolyi fissure in the literature. The cave also appears in the literature under the names Fissure cave (Dely, Mezei 1974) and Oszolyi fissure (Kárpát 1991).

Research history

The book Pilis guidebook, which appeared in 1967, mentions that on the southern side facing Oszoly Csobánka, among the limestone rocks surrounded by forest, there are several insignificant cavities. According to a publication in the 1969 Karst and Cave Research Bulletin, in August 1969 the Speleology Cave Research Group placed fixed points in the eight smaller and larger cavities on the Oszoly and Oszoly side during a camp organized in Kevélyek. On March 22 1970 and April 26 1970 László Kordos examined the cave’s climate with an Assmann aspiration psychrometer. In 1970 László Kordos and Erzsébet Wehovszky surveyed the cave with a lost‑point device and a mining compass. Based on the survey László Kordos produced and drew a 1:100 scale plan map and a longitudinal section map. The survey indicated that the cave is 5 m long and 6.5 m deep.

In the 1970 report of the Speleology Cave Exploration Group a detailed description of the cave and its research history is found. The report states that the Oszolyi Fissure opens on the D side of the third rock group, from the Oszoly Clock-face wall to É, on the Oszolyi Hasadék. The cave consists of a single fissure, which was enlarged by some solutional (cold or warm) activity. At the halfway point, the approximately 0.5 m³ rock block in front of the entrance divides the fissure. No filling is present. The cave was formed along a 35/215 strike fissure in the upper Triassic, compact, white Dachstein limestone. There is no mineral filling. Water drips on the walls during rain, otherwise it is dry. The cave can be visited without equipment. Care must be taken with the rock blocks at the entrance, because they move. It is not listed in the literature and previous investigators are unknown. In 1970 members of the Speleology Cave Exploration Group examined it. The 1970 maps were included as an annex to the report.

In the book Pilis Travel Guide published in 1974, in the list of caves of the Pilis Mountains and the Visegrád Mountains (pages 19–20), it is mentioned that among the caves of the Pilis and Visegrád Mountains are the Oszoly caves and the Fissure cave (Oszolyi-). According to the section describing the caves of the Pilis Mountains, there are about a dozen small caves among the Oszoly rocks rising above Csobánka. These were mapped and regularly explored by the Speleology Cave Exploration Group. Most of these small caves are not very spectacular, but they should be mentioned because some of them provide excellent bivouac possibilities in the Oszoly rock walls regularly visited by tourists, especially rock climbers, and in their vicinity. The 5 m long Fissure cave is located on the D side of the third rock group, rising from the Clock-face wall to É.

In the 1975 MKBT Report the 1970 report section concerning the cave was published together with the maps contained in the report. The Oszolyi fissure is located on the D side of the third rock group on the É side from the Oszoly Óra wall. It is a single vertical fissure, widened by solution. At half its height a rock block divides it into two parts. It has no filling. It developed along a 35/215 strike fissure in Dachstein limestone. The results of the climate measurements are shown in Table 1. László Kordos surveyed it in 1970 with lost points. It is 5 m long and 6.5 m deep. No earlier researchers are known. The publication contains a site drawing showing the geographic location of Csúcs Hill and the Oszoly caves. The drawing shows the geographic location of the Oszolyi fissure.

In the manuscript written by Károly Bertalan and completed in 1976 it is stated that the Oszolyi fissure, also called Hasadék‑cave, is located in the Pilis Mountains, in the Kevély group, at Pomáz. Its entrance is on the D side of the third rock group on the É side from the Oszoly Óra wall. A rock block divides its entrance. The 5 m long and 6.5 m deep cave consists of a single fissure, widened by solution processes. The cave part of the manuscript was written based on two literary works. In the 1981 Karst and Cave 1–2 semester issue it was made public that the Oszolyi fissure has the cave‑cadastral number 4820/27.

The cave Oszolyi Fissure, also known as Hasadék Cave, appears in the national cave list of the book *Caves of Hungary* published in 1984 among the caves of the Pilis Mountains. Associated with the list is a 1:500 000 scale map showing the geographical location of the caves of the Dunazug Mountains, indicating the cave’s geographical position. The guidebook published in 1991 repeats the cave description from the 1974 guidebook and the general description of the Oszoly caves. In the 1991 compilation written by József Kárpát it is mentioned that the Oszolyi fissure (Csobánka) is 10 m long and 6 m deep. The 1996 cave day tour guide repeats the description found in the 1991 guidebook, which generally presents the Oszoly caves.