Veress Márton: A Bakony természettudományi kutatásának eredményei 23. - Covered karst evolution... (Zirc, 2000)

KARSTIFICATION

Fig. 14. Passage evolution in the Alba Regia Cave (modified after ESZTERHÁS 1983) Legend: 1. limestone; 2. calcareous marl; 3. joint; 4. collapsed material; a. cavernation by corrosion in the zone of flowing karst water; b. passage formation by corrasion (during allogenic karstification); c. corrosional evolution: chimney formation on ceiling and channel development on floor (during postgenetic karstification) gentle slopes, while in the case of caving steep sides. Since in the study area the filling sediments are fine-grained unconsolidated deposits (mostly loess and its reworked varieties), subsidence or caving depends on the rate of passage clearing. (Rapid removal of material results in caving, while a slow removal brings about subsidence.) The intensity of clearing is controlled by the development stage of the system of passages (filled to what extent and by what sediments) and the thickness of the sediment fill. The above make it clear that postgenetic karstification is more complicated that syngenetic karstification. The karst passages of postgenetic karstification can be of both corrosional and erosional origin. It is also probable that during postgenetic karstification the blocking and clearing of the same passage in the same place causes the repeated infilling and regeneration of the surface landform. There are transitions between syngenetic and postgenetic karstification. A chimney under a filled depression without passage may activate (because of water infiltration the passage develops upwards) and this causes the rejuvenation of the depression. (The original depression and the karst passage could develop independent of each other. Their way and age of formation can be both different.) This type of covered karst formation is called pseudopostgenetic karstification. On the covered karst terrains of the mountains during the inheritance of chimneys into the cover sediment a variety of surface landforms develop because of the variable topography (of both the present-day and the karstic basement surface), drainage network and the various stages of exhumation. The following syngenetic karstforms are identified (Fig. 15, Table III). If during chimney formation a water-course suffers bathycapture (pseudobathycapture), a ponor with blind valley having an independent catchment is created. In the mountains