Volume XXII |

Major and minor elements contribution to discriminate between karst drainage watersheds and to outline underground hydrological connections. An example from Sohodol Valley (Vâlcan Mountains, Romania)

Abstract: Water samples for chemical analyses have been collected from impenetrable karst springs and from water flows intercepted by caves within the area of Sohodol valley. The analyzed inorganic constituents were noticed to belong to two distinct categories. One category included solutes of variable concentrations, likely related to local allochtonous inputs (Al, NO3) and to local occurrences of decaying organic matter (PO4, NO3), such solutes being hence irrelevant in terms of regional patterns of rock weathering. The other category of solutes (Ca, Mg, Na, K, Sr, Ba, Rb, Fe, HCO3 and SiO2) proved to have concentrations that did not differ between two interconnected water flows (e.g., impenetrable karst springs that discharged from a common water body; a cave stream connected to an impenetrable karst spring). Accordingly, the concentrations of this second group of constituents represented reliable chemical fingerprints of a particular karst watershed. And implicitly, water flows having contrasting concentrations of such solutes were conjectured to belong to distinct karst watersheds, which likely differed in terms of chemical composition of the karstifiable rocks, and/or of the impervious rocks which provided allochtonous recharge to the concerned karst drainage systems.

Volume XXI |

Characteristics of volcanic mountains morphostructure of Transcarpathia, Ukraine

Abstract: The study presents a detailed geomorphological characterization of the volcanic mountains of Transcarpathia. Materials of previous geological researches, including the Transcarpathian geological exploration expedition, supplemented by the results of our own field researches, are systematized. Based on the analysis of relief forms and taking into account geomorphological and tectonic factors, Vyhorlat-Gutyn morphostructure of the second order is divided into morphostructures of the third order: Poprychny, Antaliv-Synyatska, Velykyi Dil, Tupy and Oash, which in turn are divided into morphostructures of lower orders. The Mukachevo morphostructure of the second order is composed of the following morphostructures of the third order: Beregovo hills, Kosino-Biganski hills, volcanic remains (Shalanka, Chorna Gora). Based on a detailed analysis of the collected materials, it was determined that the main role in shaping the modern relief of volcanic mountains belongs to channel and temporary water flows and weathering processe; consequently, river valleys and weathering surfaces were formed, which are the most important morphosculptures. On the basis of morphological and structural-lithological approach, as well as own field research, a geomorphological map of the volcanic mountains mountains of Transcarpathia on a scale of 1: 100,000 was compiled.

Volume XXI |

Features of the morphology and dynamics of the shallow-island part of the Dolgaya Spit (the Sea of Azov)

Abstract: The relief of large coastal accumulative bodies, including cuspate spits, is an important subject in scientific and applied research. A characteristic feature of similar accumulative bodies is a shallow underwater part. The aim of this work is to study the shallow-island part structure of the Dolgaya Spit (the Sea of Azov) and to identify the natural mechanism that determines both the variability of accumulative body over short time intervals and the high stability of the geosystem as a whole. Digital elevation models (DEM) for the studied area were built on the basis of remote sensing data (Sentinel-2). It is established that the length of the shallow-island part is about 20 km. There are shelly shoals and islands with a complex configuration and relief. Sea level, the wind-wave regimes and the sediment load are the main factors that determine the dynamic equilibrium of the shallow-island part of the Dolgaya Spit and its relief. The Dolgaya Spit has distinctive features of a free accumulative body influenced by longshore sediment flow. The configuration of its surface part is characteristic of many cuspate spits formed by two sediment streams. But the shallow-island part develops under the influence of alternating transverse movements of water masses and waves from opposite sectors. The coexistence of signs of the near-shore bar and cuspate spit provides grounds for classifying the Dolgaya Spit not as a cuspate accumulative body (in particular as Azov-type spit) but as a separate type developing under joint action of transverse and longshore sediment flows.

Volume XXI |

Geodiversity Assessment by Application of Geoinformation Approach (on the Example of Golo Bardo Mountain, Western Bulgaria)

Abstract: Geodiversity is considered as a complex indicator of the abiotic environment. On the example of information about Golo Bardo Mountain (Western Bulgaria), the article emphasizes the need to develop methods for quantitative assessment of the geodiversity of an area to minimize the subjective nature of the assessment by defining clear criteria that can be quantified. The complex geodiversity assessment of the investigated area was made based on the analysis of lithology, soils, topographic features and drainage network. The analysis is done in a GIS environment. Topographic settings are analysed on the base of digital elevation model with a cell size of 30 m using Spatial Analyst Tools. The elevation model is used for calculating the terrain roughness, slope gradients and aspects of the slopes. Geological component is evaluated considering the petrographic composition of the area. The variety of the abiotic components is calculated by application of grid method (cell size 1000 x 1000 m), using Focal statistics tool, neighborhood type “Variety”. Fuzzy logic is suggested to be used for comparison of areas located in different regions and with different landscape conditions.The results of the geodiversity assessment show that most of the area of the Golo Bardo mountain has moderate geodiversity index. The method used in the article gives reliable results with minimal subjectivity, that can be used for assessment of the distribution of the geodiversity on a particular area and allow to compare different territorial units. The results obtained in the current study show good correlation between areas with high and moderate geodiversity index, and areas with high biodiversity values. The applied methodology and the visualization of the geodiversity index allow for easy understanding of geodiversity by a wide range of stakeholders, even non-geoscientists, and can be successfully applied in the planning of geotourism activities.

Volume XX |

Combining geomorphological approach and thermal monitoring for permafrost research in Rodna Mountains, Northern Romanian Carpathians

Abstract: This paper aim to investigate the possibility of permafrost occurrence in the alpine area of Rodna Mountains by describing the rock glaciers distribution and characteristics and by monitoring the ground surface temperature and spring water temperature during late summer. Rock glaciers have a rather scarce distribution between 1670 and 1960 m a.s.l., their morphology is completely relict even at the highest altitudes which indicate they are inherited landforms. Thermal regime indicates improbable permafrost at Bila talus slope (1844 m a.s.l.) and an ambiguous outcome at Curmătura Buhăescului talus slope (1980 m a.s.l.) where average temperature during the BTS period was warmer than the -2°C threshold only in one year of the two monitored. Alpine spring water temperatures are above 3°C indicating absence of permafrost and they are moderately correlated with altitude. Iezeru Pietrosu cirque headwall is affected only by seasonal frost at 2100 m a.s.l. for almost 9 months. It seems that in Rodna Mountains the past and present climate conditions were and are milder in comparison to Southern Carpathians as the latitude increase does not compensate the lower altitudes.