11. Speleogenetic factors and processes in the karst conduits of Zagorska Mrežnica Spring Cave (Croatia)Petra Kovač Konrad, 2018, doctoral dissertation Abstract: Zagorska Mrežnica spring cave is in the Desmerice village, 7.59 km SW from the town of Ogulin. The coordinates of the entrance are X: 399563 m, Y: 5006974 m, and Z: 314 m (HTRS96). The cave system is positioned in the contact zone of Jurassic limestone and the thrust front composed of Triassic Dolomite. The karst drainage system has elements of point recharge through a set of ponors in the hinterland karst poljes and diffuse infiltration through numerous dolines on Velika Kapela Mountain. The karst of Ogulinsko Zagorje area and its epiphreatic and phreatic cave systems have been intensively explored for the last eight years, resulting in the mapping of 1134 m of submerged passages of the Zagorska Mrežnica spring cave. Until 2014 it was the longest mapped submerged system in Croatia explored by cave diving techniques only. Altogether, over 3.5 km of submerged passages in seven caves of Ogulinsko Zagorje (Zagorska Mrežnica spring cave, Spring of Rupečica, Ponor of Rupečica, Cave system Pećine-Veliko vrelo, Spring of Bistrac, Cave Zagorska Peć and Pit Klisura) were explored during 500 hours of diving over a ten-year period. The goal of the research was to determine speleogenetic factors and processes in phreatic conditions. A new methodology for mapping of cave cross-sections, microrelief forms, and structural elements was developed, sediment and petrographic analysis were done, hydrological analysis before and after the building of the accumulation lake Sabljaci, 48 cross-sections of the cave passaged and a 3D model of the cave system was created, water chemistry as well as geomorphological analysis was carried out. In the end, a simplified (modified) vulnerability assessment was also done.
The results of my research showed that the distribution of the cave passages is a result of complex tectonic activities that are reflected in the orientation of cave passages. The general orientation of the measured fissures, measured during cave diving, show a dominance of a NWW-SEE direction but also the pattern of cave passages shows a significant dominance of the NE-SW orientation indicating the existence of multiple secondary traverse faults originating from main NW-SE faults. The morphology of the cave passages shows a transition between epiphreatic (possibly vadose) and phreatic phases as well as the presence of paragenetic developments in the ceiling. This indicates the existence of several epiphreatic (possibly vadose) and phreatic speleogenetic phases. The initial shape of the cross-sections was identified by sub-horizontal beds and bedding planes. The mapping of microrelief forms showed that the mechanical erosion was a very intensive process shaping the morphology of the cave passages.
The sediment mineralogy coincides with the lithology of the catchment area, and the sub- angular grains reveal relatively short transport distances. Further analysis of the catchment area’s geomorphology and its relevance for the speleogenesis of Zagorska Mrežnica cave show influence of relief structures that have a Dinaric orientation (NW-SE) with cave structures and passage orientations, great relative relief, steep slopes on Velika Kapela, and flat areas of karst poljes dictate the allogenic and autogenic hydrological regime of the cave. A 3D model of the cave system reveals a relationship between the cave system and the landscape, as well as a possible connection with the nearby Zagorska Peć cave. The modified karst vulnerability assessment shows that the catchment area of Zagorska Mrežnica spring cave has a high vulnerability ranking, mainly due to high doline density and the potential large diffuse capacity of infiltration of pollutants.
Keywords: Ogulin Zagorje, karst, spring, speleogenesis, Zagorska Mrežnica spring cave
Published in RUNG: 02.03.2018; Views: 4905; Downloads: 197
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12. THE INCIDENCE OF NEW ECOSYSTEMS (EE – EMERGING ECOSYSTEMS) IN THE KARST BIOSPHERE RESERVE : GROUP PROJECT, FINAL REPORTKlemen Cotič, Matej Pogorelc, Matjaž Reya, Barbara Šavli, Nika Feigina, Merisa Kapić, Ӧzkan Karaçam, Mariya Perepelytsya, 2017, other monographs and other completed works Abstract: The need of wood for building and heating, the extensive grazing and population growth in the 18th and 19th centuries led to turning the Karst area in Slovenia into a bare land. In the 19th century organised reforestation started which was successfully performed with Black pine (Pinus nigra J. F. Arnold). Later on, the reforestation was replaced by the process of spontaneous afforestation. The successfulness of reforestation with Black pine also made it possible for the native tree species to grow. The abandoning of the use of agricultural land also contributes to the spontaneous afforestation. In this project we determined the changes in forest cover through time. We used aerial photographs from the years 1957, 1975, 1985 and 2015. By drawing polygons on the maps in the QGIS programme on the areas that are covered with forests, are overgrown or are used for agricultural purpose we compared the areas from the maps of different years. We found out that the area covered with forest had increased by more than 50 % from the year 1957 to 2015. The increase in the area of forest cover due to afforestation provides new habitats for fauna and flora to live in.
Keywords: Karst, afforestation, new habitat, Black pine, human impact
Published in RUNG: 07.11.2017; Views: 4979; Downloads: 0
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13. Proposals for integrating karst aquifer evaluation methodologies into national environmental legislationsKatarina Kosič Ficco, 2015 Abstract: Characterization of karst aquifers in order to reduce the impacts of human activities on these vital groundwater resources poses a significant challenge for scientists, land managers and policy makers. Methods and criteria for improvement of karst management have been suggested by the scientific community in order to assure the preservation of karst groundwater resources. However, these methods are rarely integrated into national groundwater protection policies. A case-based study of a swine confined animal feeding operation sited on mantled karst terrain in the southern Ozark Highlands in the State of Arkansas, United States of America helped illustrate why karst-specific evaluation methods should be implemented in national legislation. Through the review of the area’s geomorphology and hydrogeology, dye tracer test results, and existing state and federal legislation and permitting processes for confined animal feeding operations, proposed improvements to existing legislation for confined animal feeding operations were developed. The study provides an example of how integrating science into policy-making can enhance protection of valuable groundwater resources.
The original publication is published in Sustainable Water Resources Management, Springer, ISSN 2363-5037 Volume 1 Number 4, in 2015. The final publication is available at https://link.springer.com/article/10.1007/s40899-015-0032-5.
Keywords: Karst aquifers, Vulnerability, Groundwater protection, Legislation, CAFO
Published in RUNG: 05.07.2017; Views: 4160; Downloads: 0
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14. Geomorphological characteristics of karst on contact between limestone and dolomite in SloveniaPetra Gostinčar, 2016, doctoral dissertation Abstract: Contact karst is a type of karst formed where allogenic waters from the surface influence the karst geomorphic system. Contact karst may be considered in both a strict sense and in a wide sense. In a strict sense, contact karst is the karst phenomena and forms influenced by the contact between a karstifiable rock and a non-karstifiable rock. In a wide sense, contact karst may also be the karst phenomena and forms influenced by the contact between two different karstifiable rocks, for example limestone and dolomite. This thesis focuses on the geomorphological characteristics of contact karst on limestone-dolomite contacts in Slovenia. The purpose of the research was to determine which processes contribute to the development of contact karst on the contact between limestone and dolomite, to define their dynamics, and to identify which surface and underground landforms are developed.
The spatial distribution of contacts between limestone and dolomite in Slovenia was determined in a GIS. Using existing lithological data as a data layer, the extent of carbonate rock cover in Slovenia was calculated. Carbonate rocks cover 47 % of Slovenia’s territory (27 % limestone, 14 % dolomite, and 6 % clastic carbonate or impure carbonate rocks). And, there are 1,353 limestone-dolomite contact lines in the country, totalling a length of 2,625 km.
Study areas were selected based on GIS analysis of the limestone-dolomite contacts. A total of 17 areas in Slovenia were studied in detail. Fieldwork at the study areas consisted of the collection and analysis of rock, sediment, and water samples, allowing each study area to be geomorphologically mapped.
General factors contributing to contact karst development on the lithological contact between limestone and dolomite were determined. The most important factor appears to be the characteristics of the inflow part, formed on the dolomite. Where dolomite functions as a karst rock, the water is dispersedly drained into the karst. In that case, the limestone-dolomite contact does not function as contact karst. Alternatively, where the dolomite functions as fluviokarst, a point recharge, or sinking stream, is formed. In that case, contact karst may be formed. The fluviokarstic character of the dolomite depends on its chemical and mechanical properties. The dolomite bedrock must be positioned at a higher elevation than the neighbouring limestone bedrock. To meet this requirement, dolomite beds, which in Slovenia are generally older than limestone and hence stratigraphically positioned below the limestone beds, need to be positioned above limestone by either folding that leads to inverse stratification, overthrusting, or by displacement along faults. Along faults, the dolomite is more prone to mechanical weathering due to tectonic crushing in addition to its chemical properties. Hence, contact karst is more likely to form at thrust contacts between thrust limestone and dolomite. Limestone-dolomite contact karst develops predominately at higher elevations due to increased precipitation (where allogenic inflow is higher) and greater frost action due to lower temperatures. Intense mechanical weathering of dolomite over limestone directly affects contact karst processes and significantly contributes to the spatial distribution of these types of surfaces. The location of the water table close to the surface is also a leading factor in limestone-dolomite contact karst formation due to enhanced border corrosion.
Landforms typical of contact karst were identified in the study areas during geomorphological analyses. However, they are not as clearly recognizable as those on contact between carbonate and non-carbonate rocks. The reason for this is the fact that allogenic waters from dolomitic catchment areas are by far not as corrosive as those from non-carbonate catchment areas.
Keywords: carbonate rocks, dolomite, limestone, contact karst, allogenic water, karst geomorphology
Published in RUNG: 19.12.2016; Views: 6534; Downloads: 258
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15. Hydrogeological and speleological research of the spring cave Slatinski Izvor and its recharge are (Republic of Macedonia)Biljana Gichevski, 2016, doctoral dissertation Abstract: This thesis represents a comprehensive study, giving first extensive information on the hydrogeological and speleological characteristics of the spring cave Slatinski Izvor and its catchment area. The researched spring is located in the Poreče basin of West-Central Macedonia, in the river valley of Slatinska Reka. The wider area around the spring belongs to two tectonic units. The Slatinski Izvor spring is situated on the Pelagonian horst anticlinorium, which is composed of carbonate rocks. The second is the Western Macedonian zone, and it is composed of non-carbonate rocks. The spring represents a significant potential for water supply for the settlement Slatina. Prior to this research only some basic information about the karst aquifer in Precambrian dolomite marbles was available. Therefore, my goal was to ensure better understanding of the functioning of the karst system in the recharge area of the spring, assessment of its vulnerability to various pollution sources, as well as study of karst development of the area.
Because karst aquifers have unique hydrogeological characteristics and specific nature, they also require specifically adapted investigation methods. In order to reach the main goal, speleological investigations, hydrological methods, hydrochemical methods and tracer test were used. A monitoring network was combined with regular samplings for major and trace elements analysis, which enabled considerable advances in understanding the functioning of the karst system. The data from two-year period (December 2011 – November 2013) was compared and analyzed.
The controlling of the karst development in the study area mostly depends on the tectonic and geologic conditions. Incision of Slatinska Reka is the main controlling factor in cave development by lowering the base level of karst terrains. All investigated caves (Gorna Slatinska, Slatinska II, Ovčarska Peštera, Puralo, Slatinski Izvor) have “normal” epigenic karst development. Slatinski Izvor is the youngest cave. The Slatinski Izvor spring serves as a cave entrance for the same cave and, represents the outflow of groundwater from the karst system.
A conceptual model of the karst system of the study area was developed. The Slatinski Izvor spring has typical karst hydrological regime. The karst system is well developed by conduits and rains infiltrated into vadose zone flow rapidly towards the spring. The travel time of low mineralized water within the system corresponds well with the results from an artificial tracer test. Performed artificial tracer test confirmed that the Slatinski Izvor spring is recharged by allogenic stream. The dominant apparent flow velocity of 250 m/h, a single peak of the tracer breakthrough curve and more than 87% of tracer recovered indicate a rapid conduit flow and high vulnerability of the observed drinking water source. Analysis of spatial and temporal variations of physical and chemical parameters show that waters in the study area had different origin and were transmitted along different flow paths. The origin of the water of the Slatinski Izvor spring is from non-carbonate area, but the influence of mixed limestone-dolomite sequence in the carbonate area is significant. The results point out to short residence time of the water in the karst aquifer.
The anthropogenic impact in the study area is insignificant which is reflected in the good water quality. In order to preserve it, land surface zoning was performed in terms of groundwater and spring water vulnerability to pollution according to the hydrogeological research.
A comprehensive research with a combined use of various research tools presents an innovative approach and a new contribution to the Macedonian karstological science. Applied methods proved to be successful for to study of the karst system. Finally, the results of the study have clear applicative significance in terms of drinking water management.
Keywords: karst hydrology, cave, speleological investigation, hydrochemistry, tracer test, spring Slatinski Izvor
Published in RUNG: 14.10.2016; Views: 30184; Downloads: 158
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