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1.
Hydrogeological and speleological research of the spring cave Slatinski Izvor and its recharge are (Republic of Macedonia)
Biljana Gichevski, 2016, doktorska disertacija

Opis: 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.
Najdeno v: ključnih besedah
Ključne besede: karst hydrology, cave, speleological investigation, hydrochemistry, tracer test, spring Slatinski Izvor
Objavljeno: 14.10.2016; Ogledov: 9307; Prenosov: 57
.pdf Polno besedilo (11,01 MB)

2.
Speleogenetic factors and processes in the karst conduits of Zagorska Mrežnica Spring Cave (Croatia)
Petra Kovač Konrad, 2018, doktorska disertacija

Opis: 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.
Najdeno v: ključnih besedah
Ključne besede: Ogulin Zagorje, karst, spring, speleogenesis, Zagorska Mrežnica spring cave
Objavljeno: 02.03.2018; Ogledov: 1602; Prenosov: 72
.pdf Polno besedilo (5,26 MB)

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