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Povzetek: Suspended particulate matter (SPM) and stream sediments (STS) from 66 locations (main channel and tributaries) were geochemically investigated in the Alpine transboundary river Mura to provide an integrated view of the long-term accumulation of pollutants and the present-day pollution status of the catchment, including the distribution of YREE (yttrium and rare earth elements) which are regarded as emerging pollutants due to use of modern technologies. Cluster analysis identified 4 geochemical associations in SPM for the low water regime: (1) Cu, Cd, Bi, Pb, Mn, Ni and Cr; (2) Ca, Sr; (3) U, Fe, Co, Rb, YREE, V, Ti, Mg and (4) Ba, Ga, Al and Li. Six groups were identified for STS samples: (1) YREE, U, Mn, Fe, Ti; (2) As, V, Ga, Al; (3) Ca, Sr, Na; (4) Cu, Ni, Co, Cr, Mg; (5) Ag, Bi, Pb, Cd, Zr and (6) Ba, Zn, Rb and Li. The study concluded that the identified geochemical groups reflect the geological composition of the catchment area as well as anthropogenic impacts, notably mining, steel industry, and urbanisation. The spatial distribution of YREE was identified as an indicator of sediment provenance. Eu and Ce anomalies were observed in SPM, reflecting the local geology, while the Gd anomaly may indicate anthropogenic inputs. The study concludes that STS primarily reflect the geogenic distribution of elements, while SPM is a more sensitive indicators of anthropogenic activities for the Alpine fluvial environment. Study also provides upper background and threshold values for Mura River catchment that may serve as reference values in future environmental studies.
Ključne besede: stream sediments, suspended particulate matter, cluster analysis, contaminant monitoring
Objavljeno v DiRROS: 31.07.2026; Ogledov: 124; Prenosov: 127
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Povzetek: This paper presents mineralogical, petrological, geochemical, and Sr–Nd isotopic data on volcanic rocks from the Northwestern Croatian Triassic Rift Basin, which is a locally aborted back-arc rift system of the Paleotethys. The dataset also includes their isotopic ages, along with the biostratigraphic ages of all interbedded sedimentary rocks. These volcano-sedimentary successions represent the northernmost parts of the Dinarides. The obtained 40Ar/39Ar isotopic age (243±1.8 Ma) indicates the Late Anisian age of the basaltic eruption and is somewhat consistent with the obtained Early Ladinian biostratigraphic ages of the interbedded sedimentary rocks. The initial εNd varies between −0.08 to +1.90, while the initial 87Sr/86Sr varies in a wide range from 0.704765 to 0.709248. The investigated Late Anisian to Early Ladinian calc-alkaline/shoshonitic basaltic lavas were formed through: (i) low-degree partial melting (5–14 %) of a shallow (spinel stability facies; max. depth ~33 km) magma source region in the subcontinental lithospheric mantle and (ii) fractional crystallisation in a partially open magmatic system. The magma generation also involved: (i) melts from the subducted slab, which is likely linked to the ancient, subducted oceanic crust of the Paleotethys, (ii) less abundant, previously subducted continental crustal material – sediments recycled in the mantle wedge, and (iii) a negligible contribution from depleted or an ocean-island, basalt-like mantle. These conditions suggest that the magma formed through a complex process during magma ascent through tectonically weakened crustal zones. Although the intense effusive volcanic activity during the Middle Triassic in the Northwestern Croatian Triassic Rift Basin lasted for a relatively short period (~3–4 Myr; Bithynian–Fassanian), its geodynamic evolution was complex and can be attributed to: (i) the subduction of the Paleotethyan lithosphere associated with an ensialic volcanic arc developed in an active continental margin setting, and (ii) the processes of continental rifting along the mid-Triassic margins of the Adria Plate, i.e., Greater Adria. These processes represent the beginning of rifting, which affected a greater area on the Balkan Peninsula as well.
Ključne besede: Middle Triassic, calc-alkaline volcanism, basalt suite, northernmost segment of the Dinarides, NW Croatia and E Slovenia
Objavljeno v DiRROS: 29.07.2026; Ogledov: 95; Prenosov: 93
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Povzetek: Foraminiferal assemblages and proportions of foraminiferal morphogroups were determined from Upper Triassic deposits of the Eiberg Basin and the Hallstatt Zone of the Northern Calcareous Alps in Austria (Eastern Alps). Foraminifera were hand-picked from the residue of marl samples taken from the upper Norian Pötschenkalk Formation, the middle–upper Rhaetian Zlambach Formation, and the uppermost Rhaetian Tiefengraben Member of the Kendlbach Formation. In total, 72 species from 31 genera were determined. Foraminiferal assemblages from the Pötschenkalk Formation at the Thälerergraben section are relatively diverse.Dentalina, Ammodiscus, Nodosaria, and Glomospirella dominate. Foraminiferal assemblages from the Zlambach Formation at the Rossmoos-/Stambachgraben section are also abundant and diverse. The most common foraminifera are Reophax, Dentalina, and Annulina. The uppermost Kössen Formation at the Schlossgraben section is dominated by hyaline taxa. The most common genera are Ichthyolaria, Lenticulina, and Nodosaria. At the Fonsjoch section, the uppermost Kössen Formation contains Lenticulina, Astacolus, and Trochammina. An increase in opportunists suggests variations in oxygen levels during the deposition of the uppermost Kössen Formation. The Kendlbach Formation at the Schlossgraben section is dominated by Lagenida over agglutinated taxa. Astacolus, Lenticulina, and Trochammina are the most common genera. At the Fonsjoch section, the Kendlbach Formation contains mostly Ast acolus, followed by Trochammina, Ammobaculites, Reophax, and Lenticulina. Increases in opportunists point to increased stressful conditions. An increase in nodosariid foraminifera higher up the section indicates a return to better oxygenated conditions.
Ključne besede: Upper Triassic, Pötschenkalk, Zlambach Formation, Kössen Formation, Kendlbach Formation, morphogroup
Objavljeno v DiRROS: 06.07.2026; Ogledov: 138; Prenosov: 151
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Povzetek: The Tithonian–Berriasian Chia Gara Formation in Central Iraq represents a major breakthrough in shale oil exploration. This study investigates two continuous core sections (140m and 137m) from the East Baghdad (EB1) and Balad (Ba1) oilfields, located within the intrashelf basin along the passive margin of the Arabian Plate. Comprehensive geochemical analyses, including major and trace elements, Mo isotopes, and total organic carbon (TOC), were conducted to evaluate the mechanisms controlling organic matter enrichment. The EB1 and Ba1 cores are subdivided into five and four organic sedimentary facies (OSF), respectively. In EB1, TOC values in the lower OSF 1 and OSF2 range from 3.55 to 8.0 wt.% and 2.31 to 4.42wt.% and are higher than those of the upper OSF 3, OSF 4, and OSF 5 that range from 0.5 to 3.77wt. %. In Ba1, OSF 3 and OSF 5, which range from 0.39 to 2.7wt.%. Redox indicators such as U/Th, Ni/Co, EF(U), and EF(Mo) show a progressive shift towards more oxic bottom-water conditions. The δ98/95Mo data (–0.3 to 2.5‰) confirm the presence of euxinic conditions, particularly within OSF2 in both EB1 and Ba1, thereby resolving previous uncertainties regarding bottom-water redox conditions. Primary productivity indices (Cu/Al and Ni/Al ratios) suggest relatively low productivity in deep-water slope and basinal facies. Furthermore, the upwelling indicators (EF(Co) × EF(Mn)), varying from 0 to 0.48 for EB1 and 0.05 to 0.18 for Ba1, suggest that preservation conditions played a more significant role than productivity conditions within the deep-water slope and basin. Differential subsidence, with local uplifts and erosion within the Mesopotamian Foredeep Basin likely contributed to spatial variability in organic enrichment. Overall, this study highlights the importance of the redox environment in the development of high-quality hydrocarbon source rocks in unrestricted environments that present upwelling.
Ključne besede: Mo isotopes, redox conditions, organic matter, primary productivity, geochemical methods, Upper Jurassic–Early Cretaceous, Mesopotamian Basin
Objavljeno v DiRROS: 06.07.2026; Ogledov: 169; Prenosov: 76
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Povzetek: Environmental geophysical investigations require controlled laboratory experiments to better understand the relationships between the parameters measured in the field and complex physicochemical processes occurring in the subsurface. In this work, we introduce the Geoelectrical Laboratory (GEL) of the Geological Survey of Slovenia. A typical application of the spectral induced polarization (SIP) method, focussing on the detection of electron-conducting minerals disseminated in geologic material is presented. This is demonstrated by the close relationship between the polarization peak values (�′′�), and chargeability values associated with the second peak (�2) of polarization spectra estimated from a double Cole-Cole fit, and the metal content, either by the mass % concentration of the ore mineral or the chemical composition (Pb, Zn and Fe) estimated by XRF measurements. We illustrate this for synthetic mixtures of quartz sand and pure Pb-Zn ore particles from the Mežica mine (Slovenia), the Mežica Pb-Zn mine waste material (K-material) and sediments collected from streams near the waste deposits (S-material). These results evidence promising capabilities of the SIP method for in-situ detection of metallic particles, both within the mine waste deposits and sediments in the surrounding areas. However, further SIP investigations are needed in a larger number of material samples along with geochemical, mineralogical, and granulometric data to refine the links of polarization and chargeability to both the mass content of ore and the specific geochemical composition of the materials under investigation, as well as to determine the inf luence of the natural geological materials that constitute both the host rock of Pb-Zn ore and the surrounding sediments (e.g., carbonates).
Ključne besede: induced polarization, chargeability, mine waste, sediments, Mežica, Slovenia
Objavljeno v DiRROS: 06.07.2026; Ogledov: 177; Prenosov: 77
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