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Povzetek: Slope stability strongly depends on the prevailing hydrological and hydrogeological conditions. The amount and intensity of precipitation and changing groundwater levels are important landslide triggering factors. Environmental tracers, including the chemical and stable isotope compositions of precipitation and groundwater, were used to gain insight into the groundwater dynamics of the Urbas landslide. The landslide is situated in a mountainous area with steep slopes and high precipitation amount and poses a high risk for the safety of the Koroška Bela settlement that lies downstream. The stable isotope analyses of oxygen-18 (18O) and deuterium (2H) in the precipitation and groundwater were used to estimate the groundwater mean residence time and the average altitude of the landslide recharge area. This information will help to plan and prioritize remedial landslide measures aiming to reduce the recharge of the landslide body and, thus, lower the risk of transformation of the sliding material into debris flow. The results of the chemical analysis of samples taken from springs and a piezometer show a Ca–HCO3 water type. This indicates low water–rock interaction in a landslide area composed of Upper Carboniferous and Permian clastic rocks and points to upper laying carbonate rocks and scree deposits as the main recharge area. Water samples for stable isotope analyses of δ18O and δ2H were collected from a rain gauge, springs, and a piezometer over a two-year period (2018–2020). The estimated mean recharge altitude of the groundwater at sampling points was from approximately 1700 to 1800 m a.s.l. with a mean residence time of 2–5 months.
Ključne besede: landslide, groundwater, stable isotopes, oxygen-18, deuterium, hydrogeology, recharge dynamic
Objavljeno v DiRROS: 16.03.2022; Ogledov: 758; Prenosov: 313
Celotno besedilo (3,55 MB)

Povzetek: The Radovna River Valley is located in the north-western part of Slovenia in the Julian Alps, where there is an extensive intergranular aquifer whose depth to pre-Quaternary bedrock is unknown. Therefore, to obtain information about the depth of the valley and the geometry of the aquif er two geophysical methods were used in our study; ground penetrating radar (GPR) and seismic reflection method. The low-frequency GPR method has shown to be useful for determining the depth of the groundwater and the predominant groundwater recharge. Also, the high-resolution seismic method provided an insight about the morphology of the pre-Quaternary basement with the deepest point at 141 meters below surface. Measurements of hydrogeological parameters such as groundwater level and river discharge measurements were carried out in the study area. Both data analyses showed that groundwater level and river discharge are highly fluctuatingand rapidly changing, indicating a well-permeable aquifer, implying that such an aquifer is extremely sensitive and vulnerable to extreme climate events. Both the geophysical methods and the hydrogeological information have provided important information about the morphology of the valley and the alluvial aquifer, as well as increasing the knowledge about the Radovna springs system, which will contribute very important information for future hydrogeological studies.
Ključne besede: Ground penetrating radar, Seismic reflection method, Radovna spring, hydrogeology, aquifer geometry, glacial valley, groundwater table
Objavljeno v DiRROS: 09.03.2022; Ogledov: 734; Prenosov: 322
Celotno besedilo (6,27 MB)

Povzetek: Triglavska Bistrica is a typical Alpine river in the north-western part of Slovenia. Its recharge area includes some of the highest peaks in the Julian Alps. The hydrogeological conditions and flow of the river depend largely on groundwater exchange between the karstified aquifer in the carbonate rocks and the intergranular aquifer in the glaciofluvial deposits. The average volume of the river flow is up to several m3/s. In this study, water samples from different locations along the river were analysed for stable isotope ratios of oxygen and hydrogen, major ions, and concentration of tritium activity. The correlation of major ions suggests that the recharge area consists of both limestone and dolomite rocks. The δ18O and δ2H values decrease downstream, implying that the average recharge elevation increases. At the downstream sampling site V-5, located approx. 300 m upstream from the confluence of the Sava Dolinka River, the calculated mean recharge altitude is estimated to be 1,996 m.
Ključne besede: groundwater, oxygen and hydrogen isotopes, hydrogeochemistry, recharge area, Alpine aquifer, Slovenia
Objavljeno v DiRROS: 09.03.2022; Ogledov: 890; Prenosov: 296
Celotno besedilo (3,01 MB)

Povzetek: The uppermost Ladinian to Lower Jurassic Zatrnik Formation is the lithostratigraphic unit of the Mesozoic deeper marine Bled Basin. The uppermost part of the Zatrnik Formation and the transition into the overlying Ribnica Breccia was logged at the Zajamniki mountain pasture on the Pokljuka mountain plateau in the Julian Alps. The lowermost part the section belongs to the “classical” Zatrnik Formation and is dominated by beige micritic limestone and fine-grained calcarenite. Foraminifers Siphovalvulina, ?Everticyclammina, ?Mesoendothyra and ?Pseudopfenderina are present, indicating Early Jurassic age. The beige limestone is followed by light pink limestone of the uppermost Zatrnik Formation. Slumps are common in this interval, and crinoids are abundant. Alongside some species already present in beds lower in the succession, Meandrovoluta asiagoensis Fugagnoli & Rettori, Trocholina sp., Valvulinidae, small Textulariidae, Lagenida, and small ?Ophthalmidium alsooccur in this interval. Resedimented limestone predominates through the studied part of the Zatrnik Formation, indicating deposition on the slope or at the foot of the slope of the basin. The switch to crinoid-rich facies within the slumped interval of the Zatrnik Formation may reflect accelerated subsidence of the margins of the Julian Carbonate Platform in the Pliensbachian. The Zatrnik Formation is followed by the formation of the Pliensbachian (?) Ribnica Breccia. Impregnations of ferromanganese oxides, violet colour, and an increase in clay content are characteristic. The foraminiferal assemblage consists of Lenticulina, small elongated Lagenida, and epistominids. Individual beds of the Ribnica Breccia were deposited via debris flows. Enrichments in ferromanganese oxides point to slower sedimentation.
Ključne besede: Lower Jurassic, Bled Basin, Pokljuka Nappe, stratigraphy, foraminifer, Hierlatz facies, Ribnica Breccia, Zajamniki
Objavljeno v DiRROS: 09.03.2022; Ogledov: 716; Prenosov: 303
Celotno besedilo (11,45 MB)

Povzetek: Studies of upper Palaeozoic corals from the Southern Alps (Karavanke Mountains in Slovenia and Carnic Alps along the Austrian/Italian border) started at the end of the 19th century. Since the mid-20th century, corals of the Karavanke Mountains have been studied in detail by several authors. Recently, several coral type localities and the coral groups occurring therein have been einvestigated. This paper deals in particular with the study of Carinthiaphyllum Heritsch, 1936 and all previously known data have been revised within this study. Most specimens of Carinthiaphyllum originate from museum collections and from new findings in the Dovžanova Soteska area of northern Slovenia. Additional material is represented by newly found samples from the locality of Mt. Boč in eastern Slovenia. The stratigraphic position and age of the Carinthiaphyllum occurrences are determined by fusulinid and conodont assemblages. Two species, Carinthiaphyllum crasseseptatum Gräf & Ramovš, 1965 and C. ramovsi n. sp., are described herein. New morphological features, including root-like protrusions and connecting stereoplasmic tubes, have been found for the first time in gregaria growth mode. Therefore, these new observations provide evidence of a solitary gregaria growth mode: individuals are invariably separated with contact and reciprocal support only by root-like, sometimes channeled tubes occurring as outgrowths of the archaeothecal wall. An emended diagnosis of Carinthiaphyllum is proposed herein. The studied collection is housed in the Museum für Naturkunde (Leibniz-Institut) at the Humboldt University in Berlin.
Ključne besede: Gregaria corals, Carinthiaphyllum, Asselian-Sakmarian, Southern Alps
Objavljeno v DiRROS: 04.03.2022; Ogledov: 621; Prenosov: 230
Celotno besedilo (7,42 MB)