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

METHODS

Valley formation Valley typology A successful study of processes on covered karst is only possible if types of valleys developed on covered karst are identified. Based on literature (LÁNG 1958), field observations, analyses of geological maps and theoretical considerations the following types of valleys are distinguished. - Well-developed superimposed valley: inherited over the carbonate rock surface before loess formation. Within this type the following varieties occur: The valley is not active any more; it has no or negligible catchment on covered karst; partly filled with loess or other redeposited cover sediment Inactive well-developed superimposed valleys also have a variety without or with negligible fill. There are also active well-developed superimposed valleys. These valleys receive an abundant recharge of water from the neighbouring non-karstic terrain even today. The group primarily includes gorges and narrow valleys. Although on carbonate rock surfaces part of the water from the water-courses of valleys is lost by infiltration, they still have a sufficient discharge for incision. (Valley floors can be at highly variable elevations above the karst water table, depending on the rate of valley incision related to the general uplift of the surface.) These valleys can be regressional-superimposed or antecedent-superimposed. - A developing superimposed valley: locally cutting through cover sediments, superimposed or superimposed-regressional valleys reach carbonate rocks along certain sections. Developing superimposed valleys could form on block surfaces covered by the Csatka Gravel Formation or older (eg. Cretaceous) cover sediments. Within this variety valleys occur with sections incised into the Csatka Gravel Formation and other sections in carbonate rock but their floors are mantled by loess in original deposition or redeposited. Developing superimposed or developing regressional-superimposed valleys may also form on the floors of superimposed valleys. In this case, the developing superimposed valleys more or less consume the infilled floor of the older valley and their floors may locally reach carbonate rock. Double composite valleys are created this way. Sometimes on the floors of well-developed or developing superimposed valleys minor incision may produce channels called developing regressional-superimposed channels. As a consequence, some valleys in the mountains are triple composite landforms. Valley formation and karstification The inheritance of karst valleys over carbonate rock can take place before the formation of the flowing karst water zone (pregenetic valley), more or less simultaneously (syngenetic valley) and after that date (postgenetic valley). Pregenetic valleys - if in their environs cover sediments are removed rapidly - become inactive even before their floor reaches the cavities of the karst water zone. The inactive superimposed valleys which during incision have not reached the cavities of the flowing karst water zone are pregenetic valleys, while the ones which have are syngenetic or postgenetic valleys. According to JAKUCS (1956, 1968, 1971) the surface water-courses of karst areas enter into the interior of the karst through valley floor ponors by way of bathycapture. Author distinguishes between true and pseudobathycaptures. True bathycapture occurs on true rock boundaries (where karstic and non-karstic rocks are in contact on the surface). The water