Caves of the Medves - Ajnácsk ői Mountains

The Medves - Ajnácskői Mountains form part of the Northern Hungarian Mountain Range. The major part, (300km²) lies in Slovakia, only 100 km² of it belongs to Hungary.

The base of the mountains is a denudatedMiocene sedimentary formation. The mountains have witnessed a great dealof volcanic activity. This activity began with two andesite laccolith intrusions.

Later, at the boundary of the Plioceneand Pleistocene about 100 explosion craters were formed, from which copiousquantities of basalt lava poured. Between the basalt plateaus deep erosionvalleys were formed. Ninety-six natural caves are known and 8 artificial cavities, considered as caves, are listed.

Fifty-nine caves are in Slovakiaand 37 in Hungarian territory. The caves mainly are in basalt and in one case in sandstone.. One cave, found in andesite, "Farkas-lyuk"was destroyed byquarrying, one cave in rhyolite tuff and the artificial cavities have beenexcavated in andesite tuff.

Several syngenetic caves were discoveredin the region. "Ebeczkého jaskyňa" (EbeczkyCave) and Kis-kői Basalt Cave originated from steam explosion."Studna naRagáči" ("Ragácsi-kürtő") and "Baglyas-kői-bazaltüreg" are fumarola caves.

The postgeneticcaves are fissure caves mainly created by tectonic movements."Ládovatrhlina" ("Jeges-hasadékbarlang") and " Nyáryhojaskyňa" (Nyáry Cave) were formed at the same time as the outcropingrim of the rock formation. "Dolna jaskyňav Zabode" (Zabodai-alsó Cave) developed perpendicular to therim of the outcrop. Some of the tectonic caves, for example "Skautskájaskyňa" (Cserkész Cave) and "Hviezdicovájaskyňa" (Csillag Cave) were formed by rock disintegration alongthe clusters of fissures and they are similar to pseudocaves. Of coursegenuine pseudocaves have also developed amongst the huge basalt bouldersas for example "Labirintová jaskyňa"(Labirintus-barlang) or "Zapadna sut’ova" ("Nyugati-görgetegbarlang").Szilvás-kői Cave and "Pók-lyuk" represent an interesting genotype.They are caves which formed as a result of the collapse of the abandonedcoal mines beneath the region.

The Medves-Ajnácskői Mountains have 31 caves longer than 10 m, and even 11 of the basalt caves are more than30 m in length as follows:

Forty-four caves can be found near Stará Basta in the rim of "Pohánskyhrad" ("Pogányvár") Plateau. Thirty-one caves are in "Szilvás-kő" near Rónabánya. The total length of the natural cavesis1440 m (of  this 1010 m is in Slovakia).