Veress Márton: A Bakony természettudományi kutatásának eredményei 23. - Covered karst evolution... (Zirc, 2000)
RESEARCH HISTORY
The gorges or gorge-like valleys or valley sections in the mountains are, according to LANG (1958), of superimposed-regressional (Ördög-árok, Kő-árok and Kőmosó) or superimposed-antecedent (Gaja Gorge) origin. In addition to those listed above, superimposedantecedent valleys are certain sections of the Hódos-ér, Öregfolyás and Cuha and the Kerteskő section of the Gerence stream. Opposing the views of LÁNG, however, the Kőmosó Gorge as well as parts of the Ördög-árok and Kő-árok are also referred to this group. One of the conditions to superimposed-regressional and superimposed-antecedent valley formation is cavitation below valley floor. At the same time, superimposition of valleys favours cavern formation (VERESS 1980a). General description of karstification in the mountains Various researchers often hold confronting views on the nature of the karst and particularly of surface karst in the mountains. Opinions agree on the low rate of karstification and on the different character of karst features here compared to those on the Aggtelek Karst. The reasons proposed for the explanation of variation are the following. According to RÉVÉSZ (1947) the Bakony Mountains are dominated by covered karst terrains. In places where the cover sediments are permeable, the subsidence of the limestone surface is inherited over the surface of cover sediments. LÁNG (1958) makes the recent uplift of the mountains responsible for the moderate degree of karstification. In the opinion of LEÉL-ŐSSY (1959) the minute dissection of the mountains prevented a more developed karstification. BULLA (1964) explains the poor development of karst features with the terrain being a low-lying surface until the Lower Pannonian also buried under a thick sequence of nonkarstic cover sediments. Analysing the development of karst, JAKUCS (1968) claims that the absence of bathycapture is due to the properties of cover sediments. Impermeable cover sediments could prevent the development of water conduit passages and provide favourable conditions to valley incision to the karst water table. As an example, the Cuha Valley is cited. It is to be noted here that the rapid incision of valleys, made possible by the extensive catchments over covered karst terrain, works against the occurrence of bathycapture as the passages already developed are destroyed by the erosional incision of valleys. The slow rate of karstification is explained by JAKUCS (1977) with the destruction of karst features formed previously and with the formation of newer and newer surfaces on newer and newer carbonate rocks. Thus, the karstification effects could not cumulate on the present-day surfaces. KÁRPÁT (1974) identifies two phases of karst development on the Tés Plateau: an older one with open karst development and and a more recent (present-day) one with covered karst development. In the case of the older stage the superimposed valleys and water conduit passages (streamsink caves) prove allogenic instead of autogenic karstification. The presence of cover sediments and older allogenic karstification is evidenced by (redeposited) gravels in karstic depressions (VASKOR 1983). KÁRPÁT distinduishes two phases of karst development on Kőris Hill: in Phase 1 ponor formation and erosional cavitation is characteristic, while in Phase 2 the ponors buried under loess in Phase 1 are reactivated and additional covered karst landforms develop. Although there is no morphological evidence of Phase 1 on Kőris Hill, in other parts of the mountains (eg. Som Hill or Tés Pateau) a development similar to the one outlined by KÁRPÁT has occurred.
