This paper provides an overview of the physical and chemical landscape changes that have occurred at four reference sites due to historical mining and smelting activities within Slovenia, and their ...comparison with similar sites around the World. Literature review has been made with the intention to identify major pollutant sources, its dispersion control factors, and effects. The four reference sites are Idrija, with more than 500‐year Hg mining and ore smelting history, the Meža Valley, also with a 500‐year PbZn mining and smelting history, the Celje area where Zn was smelted for 100 years and the Drava River alluvial plain, which is contaminated because of historical PbZn mining upstream. Based on the comparison between the four abovementioned reference sites and similar sites around the world that are situated in different landscapes and climates, we identified major sources of contamination, which are the erosion of mine and ore processing wastes, and atmospheric emissions of metal‐containing particles from smelters. In the first case, major control factors are rainfall pattern and river gradient, controlling erosion and sediment deposition patterns. In the second case, the prevailing control factors are topography and the dominant wind directions.
The first recovery of the conodont Hindeodus parvus from Žiri (Slovenia) a few years ago highlights this area for Early Triassic biostratigraphical study. Systematic sampling of five sections in the ...Idrija–Žiri area has yielded the new species Platyvillosus corniger sp. nov. and Neospathodus planus sp. nov. Based on these new species and other conodont elements collected here, nine discrete conodont Unitary Association (UA) zones are proposed for this area. In ascending order they are: Eurygnathodus costatus Zone (UA 1), Eurygnathodus hamadai Zone (UA 2), Foliella gardenae Zone (UA 3), Neospathodus robustus Zone (UA 4), Platyvillosus corniger Zone (UA 5), Platyvillosus regularis Zone (UA 6), Triassospathodus hungaricus Zone (UA 7), Triassospathodus symmetricus Zone (UA 8), and Neospathodus robustispinus Zone (UA 9). The conodont and δ13C data indicate that these conodonts span the Dienerian/Smithian (i.e. Induan/Olenekian) boundary interval to the Spathian, and they also indicate that Triassospathodus hungaricus Zone (UA 7) does not occur at the base of the Spathian. These conodont zones are valuable for stratigraphic correlation within Central and southern Europe, and they also promote a better correlation worldwide. Conodonts in the Idrija–Žiri area were adapted to a shallow-water environment in an epeiric ramp.
•Nine discrete conodont zones are identified for the Early Triassic in Idrija–Žiri, Slovenia.•δ13C data and conodonts indicate that these sections span the late Dienerian to Spathian.•According to δ13C data the Smithian/Spathian boundary is characterized by Foliella gardenae.•These conodonts were adapted to a shallow-water environment in an epeiric ramp.•This unique conodont sequence was probably the result of paleoecological influence and/or provincialism.
The town of Idrija is located in an area with an increased seismic hazard in W Slovenia and is partly built on alluvial sediments or artificial mining and smelting deposits which can amplify seismic ...ground motion. There is a need to prepare a comprehensive seismic microzonation in the near future to support seismic hazard and risk assessment. To study the applicability of the microtremor horizontal-to-vertical spectral ratio (HVSR) method for this purpose, 70 free-field microtremor measurements were performed in a town area of 0.8 km2 with 50–200 m spacing between the points. The HVSR analysis has shown that it is possible to derive the sediments' resonance frequency at 48 points. With the remaining one third of the measurements, nearly flat HVSR curves were obtained, indicating a small or negligible impedance contrast with the seismological bedrock. The isofrequency (a range of 2.5–19.5 Hz) and the HVSR peak amplitude (a range of 3–6, with a few larger values) maps were prepared using the natural neighbor interpolation algorithm and compared with the geological map and the map of artificial deposits. Surprisingly no clear correlation was found between the distribution of resonance frequencies or peak amplitudes and the known extent of the supposed soft sediments or deposits. This can be explained by relatively well-compacted and rather stiff deposits and the complex geometry of sedimentary bodies. However, at several individual locations it was possible to correlate the shape and amplitude of the HVSR curve with the known geological structure and prominent site effects were established in different places. In given conditions (very limited free space and a high level of noise) it would be difficult to perform an active seismic refraction or MASW measurements to investigate the S-wave velocity profiles and the thickness of sediments in detail, which would be representative enough for microzonation purposes. The importance of the microtremor method is therefore even greater, because it enables a direct estimation of the resonance frequency without knowing the internal structure and physical properties of the shallow subsurface. The results of this study can be directly used in analyses of the possible occurrence of soil–structure resonance of individual buildings, including important cultural heritage mining and other structures protected by UNESCO. Another application of the derived free-field isofrequency map is to support soil classification according to the recent trends in building codes and to calibrate Vs profiles obtained from the microtremor array or geophysical measurements.
The presented study deals with the distribution of mercury (Hg) binding forms, water-soluble Hg fraction and bioaccessible Hg fraction in the urban soil of Idrija, where the world's second largest Hg ...mine is situated. Mercury had been extracted for 500years, leaving behind a legacy of highly contaminated soils and aqueous ecosystems.
The soil was sampled at two different depths (0–10cm and 10–20cm) in 45 locations situated in urban green spaces. Additionally, four garden soil samples were collected in order to compare the results with respect to land use. Solid-phase Hg binding forms were determined with the Hg thermal desorption technique, aqueous Hg mobility with the use of water leaching test and gastric bioaccesibility with the use of simulated stomach acid extraction.
The results of the Hg thermal desorption measurements detected the presence of matrix-bound Hg and cinnabar, which are very similarly distributed at both soil depths. The median relative amount of matrix-bound Hg, which is potentially transformable, is ~40%, whereas that of cinnabar is mostly immobile, at ~60%. Water-soluble Hg concentrations range between 3.9 and 106.5μg/kg corresponding to 0.002%–1.2% of aqua regia soluble Hg (ARS Hg) in topsoils (n=45), and between 2.7 and 178.7μg/kg (0.001%–0.29% of ARS Hg) in subsoils (n=45). In garden soils (n=4), water-soluble Hg ranges between 20.3 and 48.8μg/kg (0.01%–0.09% of ARS Hg), and the concentrations remain within the concentrations in adjacent urban top- and subsoil. Gastric bioaccessible concentrations range between 0.9 and 166.1μg/kg (0.002%–3.3% of ARS Hg) in topsoils (n=44). Gastric bioaccessible Hg in garden soils (n=4) ranges between 74.7 and 442.2μg/kg (0.02%–2.04% of ARS Hg), showing similar or higher concentrations than in adjacent urban topsoils, which indicates a possible positive influence of gardening practices on gastric Hg bioaccessibility.
Both water-soluble and gastric bioaccessible concentrations in Idrija's urban soil are increased and, as such, important for the local population due to their long-term daily-based exposure. While water-soluble Hg may lead to elevated Hg concentrations in edible plants or groundwater, gastric bioaccessible Hg may lead to elevated concentrations of Hg in the target vulnerable groups of population (children and gardeners), who often undergo hand-to-mouth exposure.
•The study uses a comprehensive dataset of geochemical data.•Hg distribution and mobility was tested in a critically Hg polluted urban soil.•Water-soluble and bioaccessible Hg concentrations are elevated in Idrija's soil.•About 40% of Hg is bound to potentially transformable Hg matrix components.
The investigation of Idrija, one of the oldest mining areas in Slovenia, is an on-going field of geochemical research. Over 500years of Hg mining and ore processing resulted in widespread ...contamination, especially in soil. Past investigations showed that soil in the Idrija surroundings is seriously contaminated on a regional scale (160km2 area), mainly due to aerial emissions from an ore roasting plant in the past. This study focuses on the soil from the urban area of Idrija (3km2). Following a sampling model grid, which was developed for collection of 9 soil samples per km2, 45 sampling sites were selected and sampled. Concentrations of 10 potentially harmful elements (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Zn) were determined using aqua regia digestion. Soil samples were taken from two different depths (0–10cm and 10–20cm) in order to distinguish between possible different element sources. The results showed that only Hg concentrations were extremely high in comparison to element concentrations reported in other areas around the world, and national guidelines for soil contamination. Mercury ranges from 8 to 1210mg/kg with a median of 60mg/kg in topsoil and from 7 to 1550mg/kg, with a median of 50mg/kg in subsoil. Spatial analysis show that high Hg concentrations occur near the identified Hg sources (rocks containing Hg ore, Hg ore residue dumps and old roasting sites). High Hg concentrations cause concern, because the soil in Idrija area is often used for vegetable gardening.
•Systematic soil sampling was performed to investigate element contents•Determination of PHE concentrations in the urban soil of Idrija•Urban soil in Idrija is critically polluted with mercury•PHE, except Hg, are within representative background soil concentrations
Results are presented of the first airborne LiDAR survey ever flown in Europe for the purpose of mapping the surface expression of earthquake‐prone faults. Detailed topographic images derived from ...LiDAR data of the Idrija and Ravne strike‐slip faults in NW Slovenia reveal geomorphological and structural features that shed light on the overall architecture and kinematic history of both fault systems. The 1998 MW = 5.6, and 2004 MW = 5.2 Ravne Fault earthquakes and the historically devastating 1511 M = 6.8 Idrija earthquake indicate that both systems pose a serious seismic hazard in the region. Because both fault systems occur within forested terrain, a tree removal algorithm was applied to the data; the resulting images reveal surface scarps and tectonic landforms in unprecedented detail. Importantly, two sites were discovered to be potentially suitable for fault trenching and palaeo‐seismological analysis. This study highlights the potential contribution of LiDAR surveying in both low‐relief valley terrain and high‐relief mountainous terrain to a regional seismic hazard assessment programme. Geoscientists working in other tectonically active regions of the world where earthquake‐prone faults are obscured by forest cover would also benefit from LiDAR maps that have been processed to remove the canopy return and reveal the forest floor topography.
The rise and demise of warm-temperate Permian reefs and biostromes reflect the complex geologic history of this dynamic period. Environments suitable for reef-builders were devastated by the ...Guadalupian/Lopingian crisis, and Lopingian reefs have only been recorded at a small number of localities. The uppermost Permian limestones of the Bellerophon Formation, on the Vojsko Plateau (Slovenia), contain small, lenticular biostromes within a bioclastic wackestone/packstone lithofacies. The major biostrome builders are medium-sized coralline sponges (Demospongea and Calcarea), encrusted by smaller sponges, tube worms, sessile foraminifera, calcareous algae (Archaeolithoporella) and Shamovella (i.e., Tubiphytes), all of which are typically covered by microbial crusts. The biostromes are characteristically composed of bafflestone and bindstone, incorporating sporadic framestone. Narrow belts of floatstone surround the buildups, and sponge debris is also present in lenses within the mud matrix between metazoan bafflestones. The fossils are generally well-preserved, although the fine skeletal microstructure has been partially recrystallized. Sponges are heavily calcified, and ontogenic thickening of the skeleton can be observed in some encrusters. Framboidal pyrite, forming thin films on the inner walls of sponge chambers, suggests the presence of sulphate-reducing bacteria. These microbial symbionts may have enabled the sponges to survive in the anoxic marine environments of the uppermost Permian. The Changshingian sponge biostromes of the Vojsko Plateau represent the westernmost known occurrence of contemporary metazoan boundstones in the Palaeotethys.
•Small sponge biostromes occur in the uppermost Permian of Slovenia.•Demospongea and Calcarea acted as sediment baffles, and were often encrusted by microbes.•Pyrite framboids indicate that sponges had a symbiotic relationship with sulphate-reducing bacteria.•These symbionts helped sponges to survive in hot, anoxic environments.•Plate tectonics contributed to the loss of suitable reef habitats in the Palaeotethys in the Late Permian.
A recent slip-rate of an active fault is a very important seismotectonic parameter, but not easy to determine. Idrija fault, 120 km long, is a prominent geomorphologic feature with large seismogenic ...potential, still needed to be researched. Measurements of tectonic micro-displacements can provide insight into its recent activity. The Učja valley extends transversally to the Idrija fault and was therefore selected for the installation of TM 71 extensometer. Measurements on the crack within its inner fault zone are conducted from the year 2004. In 14 years of observations a systematic horizontal displacements with average rate of 0.21 mm/year and subordinate vertical displacements of 0.06 mm/year were established, proving the activity of this fault. An overview of methods of displacement measurements related to active faults and of newer interdisciplinary investigations of the Idrija fault is given. Displacement rates are beside for geodynamic interpretations important for improvement of seismotectonic models and thus for better seismic hazard assessment.
A comprehensive geochemical investigation of potentially harmful elements (PHEs) in household dust from the town of Idrija (Slovenia), once a world-famous Hg mining town that is now seriously ...polluted, was performed for the first time. After aqua regia digestion, the content of mercury (Hg), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), lead (Pb) and zinc (Zn) was measured. PHE-bearing particles were recognised and observed by scanning electron microscopy and energy-dispersive spectrometry before and after exposure to simulated stomach acid (SSA). Mercury binding forms were identified by Hg thermal desorption technique and gastric bioaccessible Hg was estimated after SSA extraction by ICP-MS. With regard to rural and urban background values for Slovenia, high Hg content (6–120 mg/kg) and slightly elevated As content (1–13 mg/kg) were found. Mercury pollution is a result of past mining and ore processing activities. Arsenic content is potentially associated with As enrichment in local soils. Four Hg binding forms were identified: all samples contained Hg bound to the dust matrix, 14 samples contained cinnabar, two samples contained metallic Hg (Hg
0
), and one sample assumingly contained mercury oxide. After exposure to SSA, Hg-bearing phases showed no signs of dissolution, while other PHE-bearing phases were significantly morphologically and/or chemically altered. Estimated gastric Hg bioaccessibility was low (<0.006–0.09 %), which is in accordance with identified Hg binding forms and high organic carbon content (15.9–31.5 %) in the dust samples.
The distribution and transport of Hg and other elements were studied in aquatic systems draining contaminated ancient Hg ore roasting sites Pšenk and Frbejžene trate in Idrija surroundings. Hg ...concentrations in sediments at the studied roasting site areas were found extremely high, ranging from 18 to 1240mg/kg (average 387mg/kg) in the <0.063mm grain-size fraction, and from 48 to 1080 (average 456mg/kg) in the <0.125mm fraction. Further downstream along the Padarjeva grapa Stream, which drains both contaminated areas, Hg concentrations were 330–2040 (average 721mg/kg; for <0.125mm) and 380–840 (average 531mg/kg; for <0.04mm). Increased Hg concentrations were found in the Idrijca River sediments downstream of the Padarjeva grapa Stream confluence. The results of our investigation have proved that Hg-loaded materials are not only still present at the roasting sites, but are intensively eroded and transported downstream during high waters. Consequently they have significant influence on the Idrijca River sediment contamination. Delivery of Hg contaminants from historically contaminated roasting sites via Padarjeva grapa Stream during heavy rainfalls was most intense during operation of the roasting sites, but remains an ongoing issue.
•Stream sediments are highly contaminated with Hg.•Strong effect of ancient Hg ore roasting sites on the Idrijca River sediment contamination•Delivery of Hg by storm waters from ancient roasting sites is an ongoing issue.
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