Odúsor

Odúsor is one of those natural cavity groups, smaller than a cave, located in the Pilis Mountains of the Danube–Ipoly National Park, at Oszolyo. It is also presented in tourist guidebooks.

Description

It is situated in the outskirts of Csobánka, at the Margit ridge, in one of the rock walls of Oszolyo, a well‑known climbing site. The entrance to Zsó‑cave is 3 m to the north of Odúsor. It is visible from a distance, on a route often used by climbers. The cavity series formed along a sloping fissure. At the bottom there is a cave‑like niche, then upward several smaller and larger recesses can be observed. It was probably created in the upper Triassic compact white thick‑bedded Dachstein limestone by thermal water. There is no sedimentary fill. Calcite occurs in the fractures of the host rock. The cavities are dry; when it rains water drips down the walls. The upper part of the cavity group can be reached using rope‑technical equipment.

In 1974 the cavity group was first called Odúsor in the literature. It also appears in the literature under the names Odusor (Kordos 1971), Oszolyi‑odusor (Kordos 1975), Oszolyi odusor (Bertalan 1976), Oszolyi‑Odusor (Kordos 1975), Oszolyi‑odúsor (Dely, Mezei 1974) and oszolyi Odúsor (Kordos 1984).

Research history

In the 1967 book *Pil​is guidebook* it was reported that on the southern side facing Oszolyi Csobánka, among the forest‑surrounded limestone rocks, several insignificant cavities are found. According to the notice published 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 of Oszolyo and the Oszolyo side during a camp organized in Kevélyek.

In 1969 László Kordos and Erzsébet Wehovszky surveyed with fixed points, a mining compass and, based on the survey, László Kordos drew and edited its plan map and longitudinal section map with cross‑section, which were made at a scale of 1:100. According to the survey it is 4.6 m long and 13 m deep. In that year László Kordos produced a colour slide on which Odúsor can be seen.

On 22 February 1970, 22 March 1970 and 26 April 1970 László Kordos and P. Welker performed climatological measurements on the surface and in the lower cavity with an Assmann aspiration psychrometer. The Speleology Cave Research Group’s 1970 report contains a detailed description of the cavities. The report reads that from the Zsó cave to É it is about 3 m. The 1969 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 between the caves of the Pilis Mountains and the Visegrád Mountains are the Oszoly caves and the Oszolyi‑Odúsor. According to the section describing the caves of the Pilis Mountains, there are a dozen small caves among the Oszoly rocks rising above Csobánka. These were mapped and regularly explored by the Speleology Cave Research Group. Most of these small caves are not very spectacular, but they must be mentioned because in the rock walls of Oszoly, which are regularly visited by tourists, especially rock climbers, and near them some provide excellent bivouac possibilities. In the rock wall of the Oszoly collapse the small cavities of Odúsor, well known to climbers, are arranged. 3 m from Odúsor, under the Small Overhang, there is a 12 m long cave.

Published in the 1975 MKBT Report was the 1970 report section concerning Odúsor together with the maps included in the report. According to the study Odúsor is 20 m long and 13 m deep. The publication contains a site drawing showing the geographic locations of Csúcs-hegy and the Oszoly caves. The drawing also shows the geographic location of the Oszolyi‑odusor.

The manuscript written by Bertalan Károly and completed in 1976 states that the Oszolyi odusor is located in the Pilis Mountains, in the Kevély group, at Pomáz. It is situated 3 m east of the Oszolyi Kis‑áthajlás (climbing site). It is 4.6 m long and 13 m high. It can be used as a climbing school. Steep rock fissures with cavities stacked above each other, of which only the lowest is cave‑sized. The manuscript’s cave section was written based on three literary works. In the 1981 Karst and Cave 1–2 semester issue it was made public that Odusor’s cave‑cadastral number is 4820/18. In the 1984 book *Caves of Hungary* the national cave list includes the cavity group named Oszolyi Odúsor among the Pilis Mountains caves. Associated with the list is a 1:500 000 scale map showing the geographic location of the Dunazug Mountains caves and the geographic location of the cavity group.

In 1990 Kárpát József drew an overview map on which the geographical location of the caves of the Osló (Oszolyi) rock climbing school can be seen. The map does not show Odúsor. The guidebook published in 1991 repeats the description of Odúsor from the 1974 guidebook and the general description of the Osló caves. The 1991 compilation written by Kárpát József does not contain it. The 1996 cave day guidebook repeats the cave description from the guidebook published in 1991 and the general description of the Osló caves.

On 6 June 1997 Kárpát József, based on his 1990 Osló overview map, had Kraus Sándor draw a site map showing the geographical location of the caves in the D section of the Osló rock groups. The map shows the geographical location of Odúsor. In Kraus Sándor’s 1997 report it is stated that the Osló-Odúsor was already known and had a map before 1997. The 1997 site map was included in the report. The book published in 2005 titled Hungarian Mountain Sports and Tourist Encyclopedia mentions that in the Osló forest small rock pillars and small cave openings are scattered alternately.