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Caves of the Börzsöny Mountains

The Börzsöny Mountains is a medium height mountain region, which is basically volcanic in origin. It lies between the Danube, the Ipoly River and the Nogádi Basin and covers an area of 600 km 2 .   The mountain range is mainly made up of the denudated residual of a stratovolcanic blanket. In the middle section a collapsed caldera can be proved. The edge of the mountains form an undulating upland, including few sedimentary formations.

In the volcanic rocks of the Börzsöny Mountains 110 natural, non-karstic, caves are known. Furthermore, one small cave occurs in Miocene limestone and four artificial cavities, referred to as caves, are listed. Commonly occuring andesite agglomerate is most suitable for cave development. Eighty-eight caves can be found in this formation. The compact andesite covers a smaller area where 9 caves are to be found. Six caves have been formed in andesite tuff and conglomerate. Artificial cavities have been deepened in rhyodacite, pyroxeneandesite and anesite agglomerate.

Three caves have a syngenetic origin. These are scientifically the most interesting caves of the region. The andesite cavity of Rózsabánya in Nagybörzsöny was found during mining operations in 1955 at a depth of 922 m. It is a cavity in a dyke, which was formed by the stretching effect of high pressure and hot solutions. Its walls were decorated by large individual crystals. Unfortunately these decorations have long since been destroyed.

The "Kámori-rókalyuk" was formed by the stretching and dissolving effect of ascending hot solutions in the semi-plastic lava rock. It is a 11.5 m long tube forming a horizontal cavity. The only 2 m long fumarole tube, Jókofág Cave, has a similar origin.

Most of the caves in the Börzsöny Mountains are postgenetic. They were formed in andesite agglomerate by tectonic movement ("Alsó-Rab-lyuk", "Jancsi-hegyi Cave"), either by collapses along the bedding planes (Pléska Fissure Cave, Itató-vízesési Rock Shelter) or by the lateral erosion of a creek (Rakottyás-patak Cave, Pogány-völgyi Rock Shelter). Most common are pseudocaves, formed amongst the large boulders ( Holló-ki Lámpás Cave, or the Kalapos Rock Shelter).

Many of the caves have been artificially widened in order to facilitate human utilization, for example the Remete Caves at Nagymaros, " Haramia-lyuk" and  "Hugó-villa" and the 200 m long Medve Cave (Medvedia jaskya) in Slovakia.

The caves of the Börzsöny Mountains are generally small. Their average length is about 4 m. Only the following 4 caves are longer than 10 m:

1.

Medvedia jasky a

andesite agglomerate

Ková ov

Kb. 200 m

 

2.

Church among the Remete Caves

andesite agglomerate

Nagymaros

29

/+3,5 m

3.

Holló-k i Lámpás Cave

andesite agglomerate

Percsény

17,8

/+1 m

4.

Jaskya Nóri

andesite agglomerate

Ková ov

13,3 m

/+1,8 m

5.

"Kámori-rókalyuk"

andesite agglomerate

Borsosberény

11,5

/-2 m

6.

Cavity of Rózsabánya

hyperstene andesite

Nagybörzsöny

Appr. 10

/+ 6 m

Four fifths of the caves occur in the northern area of the mountains, only a fifth of them are in the southern area. Most of the caves can be found in the regions of Kemence (32 caves) and Peröcsény (23 caves). The total length of the non-karstic caves in the Börzsöny mountains is 773 m.

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