Hosszú Hill No 5 Cave

The Hosszú-hegy 5th cave is one of the caves located in the Pilis Mountains within the Danube–Ipoly National Park.

Description

The cave entrance is at ground level of a small stone quarry on the EN side of Hosszú-hegy, in the outskirts of Pilisszántó, at a distance of DK from the mountain ridge line. At the highest point of the road connecting Pilisszentkereszt with Pilisszántó, a wide service road branches off from the main road and runs along the side of Hosszú-hegy. A green‑band tourist sign is painted on this road. About 400 m from the road the green‑band marked tourist path turns right. Here, in the forest, there is a small stone quarry, and at the back, on the left side, is the cave entrance.

The cave formed in Dachstein limestone beneath Oligocene Hárshegy sandstone. The creation of its present form can be divided into at least three phases. In the first stage, mixing corrosion and acidic water activity exerted their influence, causing the hollowing. The existing cracks were clearly widened and shaped by water. In the next stage, stagnant, slowly sinking water deposited thin‑layered calcareous clay layers and crystal formation began on the walls of the cavity. In the third stage, water seeping through the fissures widened the cracks on the floor of the passage, characteristically eroded them, and then completely blocked them, except at one point. At this point the water’s path is indicated by a fissure about 4–5 cm wide and of uncertain depth.

In the entrance area, external air dominates. At the far end a slow but constant air exchange can be observed. In contrast, in the middle sections the air is sometimes still (depending on the external air) and moisture forms. Precise, long‑term climate measurements have not been carried out inside, but occasional measurements indicate a temperature of 6–8 °C for the cave air.

In 2011 the cave was first called the Hosszú-hegy No. 5 cave in its literature. It also occurs in its literature under the name Hosszú-hegy new (Crystal) cave (Kocsis, Turi 2007).

Research history

It was published in the 1948 Hydrological Gazette that with the uplift of Hosszú-hegy the karst water level descended in Hosszú-hegy and the operation of the Ziribári, Hosszúhegyi, Pilisszántói and Szurdokvölgyi cave spring series ceased.

In the joint report of the Anubis Cave Research Group and the Adrenaline Cave Research Association in 2007 it is stated that the Hosszú-hegy new (Crystal) cave is 17 m long, 1.5 m deep and 1.5 m high. In the quarry that provides the cave, very beautiful tetrahedral 2–3 cm calcite crystals can be observed on the quarry wall, a small cavity opening at floor level, and the very cold air drew attention to the possibility that there might be a cave here. In the cave, in 2007, the two groups' members worked seven times, a total of 460 hours divided among persons. The exploration of the cavity and the removal of the fill progressed very quickly. The fill (certainly due to mining explosions) in the first vertical, fissure-like part consisted only of calcite crystals found in the rubble, sometimes mixed with cave clay. Here, 3–5 cm crystals were no longer rare. The walls were decidedly soft, in some places covered with calcite.

In the second, horizontal part the fill can already be divided into two sections. The upper level consists of humus mixed with pine needles, and the lower part is calcite 15 cm thick. The humus was animal dung, which was proven not only by traces and seed remains but also by the position of the fill, because it could not have entered naturally. On this approximately 14 m long section the walls contain much more calcite. This part was discovered as an entirely air-filled passage, only the ground‑level fill was removed. At the end point work can be continued in two directions for the discovery of further passages. It was planned to continue the removal of the fill from the cave in 2008. Mapping of the passages is in progress. Five colour photographs illustrating the cave were attached to the report.

According to the joint report of the two groups in 2008, the cave is about 17 m long, 1.5 m deep and about 2 m high. In 2008 the two groups worked in the cave three times, a total of 22 hours. The uncovering of the chamber and the removal of the fill proceeded very easily. The work consisted of carrying out the accumulated fill in the passage at the end of the cave. At the end point, after an ascent of about 1.5 m, there is a nice dome chamber where the next task is the sinking of the floor level. In 2009 the two groups worked twice, divided among persons, a total of 60 hours in the new (Crystalline) cave of Hosszú Hill. The groups' members cleared the entire human‑accessible part of the cave and determined that every end point terminates in stalactite. Further exploration of the cave is unnecessary due to the discovery of additional cave passages. The two groups finished the exploration of the cave. In Szokol Adrienn’s 2011 manuscript there is a site plan showing the geographic location of the caves in the 4830 cave‑cadastral area. The figure marks the geographic location of Hosszú Hill No 5 cave. The manuscript states that Hosszú Hill No 5 cave is located on Hosszú Hill. It is a cave 17 m long and with a vertical extent of 3.5 m.