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Volume XIX |

The occurrence of the armored mud balls during the flash flood phases of the streams from the Meledic Plateau – the Curvature Subcarpathians, Romania

Abstract: Armored mud balls that form in fluvial environments were observed on the river bed of two small streams from South-East Subcarpathians Bend, in the area of Miocene deposits with salt dia-pirs. Pieces of well-rounded clay mate-rial but with coarse surface were found on the gravel banks as well as partially submerged into stream channel and embedded in soft sediments of stream banks. The surfaces of mud balls, nearly spherical and ranging from 5 cm to 17 cm in diameter, were studded with sand grains and gravel that collected during flash floods as a result of bedload transport. The main source material of the armored mud balls consists of dark clay material detached from the cap rock of the salt massif that is crossed by the two streams. The newly formed armored mud balls, which were found among the gravels on the stream bed following the summer flash flood event from June 2019, supports the fact that these particular sedimentary features form during exceptional floods when pieces of clay material are rolled by the high-energy water flow, which results in acquiring of their spherical shape and the pebble shell. This paper represents the first report on the occurrence of modern armored mud balls formed in a fluvial environment, located in the Curvature Subcarpathians, Romania.

Volume XVII |

The analysis of relationship between microclimate and microbial carbon-dioxide production in the soils of the Tapolca and Gömör-Tornai karst terrains, Hungary

Abstract: In the karst areas, the epikarst system is a very sensitive environment, due to its position at the interface between soil and vadose zone. The epikarst is a weathered zone that develops as a result of both abiotic and biotic processes. In this paper we present the result of the complex investigations of epikarst zone which overlap dolines within two typical karst areas (Gömör-Torna and Tapolca) from Hungary, based on multicriteria analysis techniques (microbiological activity assessed as biomass amount and CO2 production, seasonality of air and soil microclimate, slope orientation and exposition), in order to reveal control factors of karst processes, the territorial and local distinctions of karst dissolution that occur in the epikarst zone. The data were compared, taking into account the human activities’ impact on both sampled study areas. After four years of monitoring, the results show that there are significant seasonal and diurnal variations of physical, chemical and biotic parameters of soil that cover and affect the epikarst zone. Spatial variations of these parameters were recorded as well.

Volume XVI |

Changes of the karst landscape and epikarst system in the area of the Tapolca karst terrains, North-West Balaton Highlands, Hungary

Abstract: The caves in Hungary have been protected for a long time. The current national legislation on nature conservation states that all known and unknown caves are under ex lege protection but the karst areas above them are not. The territories above the caves can be owned by the state but also some of them belong to private owners, thus a great diversity of economic activities are conducted on them. Anthropogenic activities endanger both directly and indirectly the caves environment and the karst ground waters. The damages and pollution of caves take place through the epikarst systems which are in direct connection with the topographic ground surface. Therefore, it is of special significance to emphasize the natural processes taking place in epikarstic systems as well as to analyze the changes within epikarst terrains caused by human impacts. The effects of human impacts on epikarst system in the area of the Tapolca karst were analyzed both by field and laboratory methods. The historical evolution of land cover and land use was assessed related to the impact on the abiotic elements (soil and karstic cover-deposit, water) in Tapolca area. The intrinsic vulnerability was assessed using the semi-quantitative COP Method. The results show high resource vulnerability in all analyzed epikarstic sites.