Bauxite is a critical raw material with high importance for the European Union economy. Bauxite has versatile applications in industries: aluminium production (approximate to 90%), the chemical industry (aluminium sulphate, chloride, sodium aluminate, trihydrate), cement (high-alumina cement), refractory production, and abrasives (brown- and white-fused alumina). The Republic of Croatia hosts bauxite deposits with variable potential: (1) High-potential deposits include Jurassic bauxites in Istria (total reserves >5 Mt; Al2O3 50-60 wt %, Fe2O3 10-22 wt %, SiO2 >16 wt %) suitable for cement and structural clay production, and Upper Eocene Promina bauxites in Dalmatia (total reserves >5 Mt) suitable for cement and/or structural clay production; the REE content in the Promina bauxites reaches up to 3,495 ppm, representing a potential secondary sources of critical elements. (2) Medium-potential deposits are the Upper Triassic clayey bauxites (at Lika, Kordun, north Dalmatia), with individual deposits up to several hundred thousand tons, and total remaining reserves of several million tons. Their low Al2O3 and high SiO2 make them suitable for brick and structural clay production. (3) Lowor no-potential deposits include the Lower Cretaceous, Miocene, Palaeocene, Upper Cretaceous, and Mid Eocene bauxites, with small reserves (10-35 kt) and limited industrial use. A case study of the Upper Eocene Promina bauxite beds (approximate to 2.4 Mt remaining reserves) shows lens-shaped or pseudo-layered deposits in karstified limestones (up to 30 m thick). Historical extraction used open-pit and underground mining (& Ccaron;veljo Dolac approximate to 80% underground, Mamutovac 100% surface, Krste Radas 100% underground). Bauxite is mainly suitable for cement and structural clay production; the bulk value of remaining reserves is estimated at approximate to 42 M & euro; (market price approximate to 20 & euro;/t). The deposits are enriched in critical elements: Ti approximate to 10.4 kt, Cr approximate to 0.6 kt, V approximate to 0.5 kt, Ni approximate to 0.2 kt, and Sigma REE approximate to 1.4 kt, representing potential secondary sources for future industrial and strategic uses.
The Velebit Mt. was uplifted by multistage tectonics resulting in the formation of an approximately 150 km long, NW-SE striking anticline comprising a Late Palaeozoic to Cenozoic carbonate-clastic succession, with a major orogenic event in the younger Palaeogene. This study focused on the tectonostratigraphic investigation of a massive Tectogenic carbonate breccia (TCB) studied in the Northern Velebit area, known in the Croatian literature as the Jelar or Velebit breccia. Results of field investigations along eight profiles show that the Northern Velebit represents an ENE-verging fold formed by general E-W (ENE-WSW) contraction in the hangingwall of the NNW-SSE oriented fault, a terminal strand of the NW-SE striking Bakovac Fault Zone. The Palaeogene (-Early Miocene?) and post-Early Miocene tectonic activity resulted in NNW-SSE/ESE-WNW oriented compression, followed by NE-SW and NW-SE extension as a result of the gravitational collapse of the Northern Velebit anticline. N-S and E-W striking dextral/sinistral faults suggest NW-SE/NE-SW and ESE-WNW oriented transpression/transtension in the Northern Velebit area after the Early Miocene. Repeated structural reactivation/tectonic inversion within the Northern Velebit anticline hinge area affected the Jurassic-Cretaceous carbonates, especially along the strike of the fault/fracture systems, which resulted in prolonged brittle deformation, i.e., cataclasis, brecciation, and formation of the TCB. Within the part of the study area marked as carbonate breccia on existing geological maps, on average, 67% of eight studied profiles are actually composed of Upper Jurassic and Cretaceous limestones (and some dolomites). Between those rocks and the TCB typically a transitional zone from metres to a few tens of metres wide can be observed, composed of (1) intensely tectonised limestones/dolomites, and (2) crackle/mosaic carbonate breccia, covering approximately 12% of the total profile length. Tectogenic carbonate breccia in the study area are mostly represented by (3) monomictic carbonate breccia and (4) polymictic carbonate breccia, while (5) carbonate conglomerates and breccia-conglomerates form only rare small lenses. TCB lithotypes crop out along approximately 21% of the profile length marked as carbonate breccia on the ex-isting geological maps of the study area. Most of the TCB outcrops were observed in the central zone of the Northern Velebit, while intensely tectonised limestones, crackle/mosaic carbonate breccia and Upper Jurassic and Cretaceous carbonate rocks predominate in the eastern and western parts.
This study investigates the origin, geometry, and deformation of faults in turbidite deposits thatform submarine fans of the upper Burdigalian-lower Serravallian Cing & ouml;z Formation, in the Adana Basin, southern Turkey, as revealed in newly exposed road cuts. Field observations indicate their synsedimentary origin based on two principal criteria: (i) undeformed younger units of the same formation overlie the faults, (ii) younger beds in a local area are flexurally deformed into a hanging-wall depression, forming a monoclinal, step-like fold, with the remaining part of the depression above the fold subsequently infilled by locally reworked intraformational sediments. The faults predominantly occur within sandstone-dominated middle-fan deposits. They are high-angle normal faults with preferred orientations in two principal directions and generally occur as single structures; however, some appear as parallel synthetic faults or as paired faults forming small-scale horst and graben geometries. The displacement of the faults is often uncertain due to the absence of marker horizons. Nevertheless, a displacement of 10-15 cm was measured on one fault pair, and an estimated displacement of 4.8 m was identified on another fault. The faults exhibit zones of variable width, some of which contain breccia and cataclastic infill. Deformation features associated with faulting include drag folds, secondary faulting within shear zones, and monoclinal flexural collapse. Within a broadertectono-sedimentary framework, we propose that deeper-seated faults at the base of the foreland basin indirectly controlled the development of these synsedimentary structures. The faults probably occur due to tectonic subsidence of the basin, which is facilitated when the sediment achieves sufficient consolidation by the weight of the overlying deposits.
Reliable and up-to-date information on mineral resources is an essential foundation for strategic decision-making and long-term mining project planning. In Croatia, solid mineral resources have traditionally been classified using the national ABC1 system, which is not aligned with internationally recognised reporting frameworks. This study applies the United Nations Framework Classification for Resources (UNFC) to a representative group of Croatian exploitation fields. In the national regulatory context, this term refers to a formally defined project category used by the mining authority to describe the legal and operational status of the mining project. The analysed group includes active and non-active exploitation fields, historic exploitation fields, and examples characterised by temporary administrative irregularities, defined as situations in which mining activities continue under acquired rights, rather than under an active concession. Two complementary approaches were used: the ORAMA (2019) decision-flow methodology and the direct application of the UNFC Guidance Europe (UNECE, 2022). Independent assessments on the non-active exploitation fields conducted by two experts, resulted in fully aligned UNFC classifications despite differences in analytical emphasis. This outcome demonstrates the reproducibility and robustness of the UNFC framework. An additional example illustrates the dynamic nature of the UNFC by showing how temporary changes in project status can influence the project maturity and assigned category. The results confirm that the UNFC provides a transparent, adaptable and harmonised framework suitable for integrating Croatian mineral resource data into national and European reporting systems. Rather than replacing the national system, this study demonstrates a practical and transparent pathway for UNFC implementation and interoperability with wider relevance beyond the Croatian context.
The cockroach Praeblattella VR & Scaron;ANSK & Yacute;, 2003 is a cosmopolitan genus recorded from the Mesozoic localities of Japan, Mongolia, the Russian Federation, South Korea, Thailand, Myanmar, Kazakhstan, Mongolia, India and USA, ranging in age from the Oxfordian to the Campanian (Late Jurassic to Late Cretaceous). Until now, two species were described from the amber of Cretaceous age, from North Myanmar Praeblattella patrickmuelleri & Scaron;M & Iacute;DOV & Aacute; in & Scaron;M & Iacute;DOV & Aacute;, BRUTHANSOV & Aacute; & HAIN, 2024 and Praeblattella continuosa & Scaron;M & Iacute;DOV & Aacute; in & Scaron;M & Iacute;DOV & Aacute;, BRUTHANSOV & Aacute; & HAIN, 2024. A new species from Myanmar amber, Praeblattella aliciae sp. nov. is described here, with characteristic pale forewing longitudinal colouration (including distinct dark maculae) and a venation scheme typical for the genus. The geographic distribution of Praeblattella fossil specimens is also given. Due to its high level of preservation in amber, this new species expands the fossil record and contributes to a better understanding of the morphology of this cockroach genus. It is unique in revealing characteristics transitional to its descendant family, the Ectobiidae.
This study examines impure grey marble occurring as interlayers in amphibolite and diopside-amphibole schists which belong toAthe magmatic-metamorphic complex of Mt. Moslava & ccaron;ka Gora in Croatia. The marble is composed mainly of calcite with abundant accessory minerals: dolomite, forsterite, spinel, pargasite, phlogopite, ilmenite, apatite, Ti-clinohumite, tremolite, Achlorite, serpentine and talc. ADetailed descriptions of mineral assemblages, their textural relationships and mineral chemistry analyses in situ, as well as compositional maps of characteristic mineral assemblages, revealed that the marble experienced at least three different metamorphic stages. These can be summarized as follows: a) the regional metamorphic stage characterised by peak metamorphic stage in granulite facies and a mineral assemblage consisting of calcite + dolomite + forsterite + spinel + pargasite + phlogopite + ilmenite + apatite; b) the stage of subsequent infiltration of an external Ti-rich, fluorinated fluid into the marble giving rise to the origin of Ti-clinohumite, the Ti content of which varies from 0.070 to 0.325 pfu and its XF value, defined as F/(F + OH), is in the range of 0.32 to 0.57; c) the stage of uplift and exhumation of the terrain causing diverse retrograde metamorphic reactions such as the replacement of Ti-clinohumite, spinel and pargasite by chlorite, formation ofAtremolite on the rims of pargasite and forsterite, as well as the replacement of forsterite by serpentine and talc. Due to the differences in the age determinations of both metamorphisms and magmatic intrusions, good correlation between the occurrence of the Ti-clinohumite bearing marbles of Mt. Moslava & ccaron;ka Gora with those found in surrounding terrains, for instance in Alps (Switzerland/Italy, Austria, Czech Republic) and Rhodope massif (Greece), Acould not be established at this stage of the investigation.
A rich but poorly preserved Lower Tithonian faunal assemblage is reported from the abandoned quarry/lime kiln at Zeng & odblac;v & aacute;rkony (Mecsek Mountains, Hungary). Some LowerTitho-nian Tethyan ammonite zones (Hybonotum, Semiforme, and Fallauxi) are recognised. The Fallauxi Zone is recorded forthe firsttime from the region. The pelagic fauna is dominated by ammonites and their aptychi. Brachiopods, belemnites, and very rarely bivalves are accessory elements of the fauna. The mollusc fauna comprises 167 specimens that represent 18 genera and 13 species. Sublithacoceras rhodaniforme, Pseudopallasiceras toucasi, Biplisphinctes pseudocolubrinus, and Physodoceras cf. widerai are recorded for the first time from the Mecsek Mountains. The ammonite fauna has a typical Mediterranean character. Based on cluster analysis, the Mecsek ammonite fauna is closest to the ammonite assemblages of the Transdanubian Range (Hungary). Based on quantitative analysis, the fauna is similar to the ammonite assemblages of the Apennines Veneto-Trento (Southern Alps, Italy), and Rogozn & iacute;k (Pieniny Klippen Belt). The microfacies is the Globochaete-Sacco-coma microfacies. Large-sized pygopid brachiopods, serpulid tube worms on inoceramid shells, and benthicforaminifera indicate optimal bottom conditions. Pelagic faunal elements (Saccocoma sp., globuligerinid planktonic foraminifera) are also present, and calcareous dinoflagellate cysts (Carpistomiosphaera malmica/tithonica) are also recorded.
The External Dinarides, with an abundance of both autochthonous and allochthonous organic matter, have been the subject of sustained petroleum exploration by INA-Industrija nafte, d.d. (INA), Croatia's national oil company, since the 1960s. To evaluate the residual hydrocarbon potential, a comprehensive suite of geochemical analyses, Aencompassing over 5,000 samples from drill cores, cuttings, outcrops, and formation fluids, have been performed. These investigations have delineated potential source rocks within various stratigraphic horizons and established critical genetic linkages between these source rocks and generated hydrocarbons, thereby refining the understanding of the region's petroleum systems. This article syn-thesizes INA's key findings derived from the extensive source rock data analysis, offering valuable insights into the remaining hydrocarbon prospectivity of the External Dinarides.
This study presents late Badenian (= early Serravallian) shallow-water marine environments in the Veliki Izvor and Nikoli & ccaron;evo areas in eastern Serbia. Biostratigraphically, the Upper Badenian Bulimina-Bolivina Zone and Ammonia/Elphidium impoverishment Ecozone are documented and correlated with the M6 zone, characterized by the presence of Orbulina suturalis. The Upper Badenian coarse- to medium-grained marine clastics transgressively overlie older Cretaceous flysch, carbonates, and volcanoclastics as well as early Miocene continental deposits. Comparative sedimentological and palaeontological analyses of the two outcrops reveal different depositional environments, water level fluctuation, and redepositional processes. The Veliki Izvor area represents a shallow-marine, tidally influenced system, whereas Nikoli & ccaron;evo is characterized by a more proximal, fluviodeltaic setting with evidence of episodic carbonate influx. Numerous well-preserved fossils of corals, bivalves, and gastropods, along with poorly preserved foraminifera and ostracods, indicate a marginal marine, well- oxygenated environment of normal salinity. Benthic foraminiferal assemblages (dominated by Elphidium-Biasterigerina-Ammonia specimens) suggest deposition in a well-oxygenated inner to middle shelf setting. A higher proportion of euryhaline genera such as Elphidium and Ammonia points to episodic freshwater inflows into the marine environment. Rare occurrences of Bolivina and Heterolepa specimens indicate brief periods of low oxygen conditions, while the Elphidium-Biasterigerina assemblage reflects recovery phases with renewed vertical water circulation and bottom water oxygenation. Low-diversity ostracod assemblages further support the shallow marine environments. These findings contribute to a better understanding of marginal Miocene basins in southeastern Europe and highlight the complexity of shallow-water marine depositional systems.
The late Pennsylvanian Kounov coal seam yielded exceptionally well-preserved vascular elements. Their determination is questionable due to their fragmentary nature. Scalariform, reticulated and pitted tracheids prevail. They are comparable with the sphenopsid plants Arthropitys and Sphenophyllum. Some scalariform and reticulated tracheids also resemble those of ferns. However, their precise determination is not possible. Some uniseriate pitted tracheids resemble some conifers. Because conifers do not occur in coal, they might belong to secondary wood of some calamitaleans. Dispersed vascular tissues are correlated with dispersed cuticles and macrofossils.
The tectonic structure and orogenic evolution of the central part of the External (Outer) Dinarides in Croatia (northern Dalmatia, Velebit, and Lika) has been interpreted in different, sometimes conflicting ways. One of the recent models interprets the External Dinarides as a fold and thrust belt, characterized by the early orogenic thin-skinned contractional phase, followed by thick-skinned exhumation and related gravitational collapse of the thin-skinned cover. Another recent model offers the same tectonic style in the first phase of the orogenesis, followed by formation of a triangle zone and low angle north directed passive roof backthrusts in the intermediate phase, and final uplift because of antiformal south directed duplex stacking and multiple thrusting in the former tectonic basement. However, despite up-to-date geological cross section analysis, the later model seems to lack field data supporting it. This paper will discuss the need for such a complex and completely new regional tectonic interpretation that requires more thorough checking of existing observations previously published in numerous local studies and maps, and meticulous redebating of earlier interpretations before they are replaced. Moreover, it is concluded that the former model, reinterpreted here, combining the early-orogenic thin-skinned and late-orogenic crustal thick-skinned tectonics, seems to fit better both the seismological fault mechanism solutions and updated geological maps of the area.
Human-induced changes in sedimentation rates, pollution, and eutrophication significantly transformed the benthic communities in the northern Adriatic Sea during the late Holocene, particularly in recent centuries. Fossil assemblages from sediment cores record these changes but are often affected by stratigraphic condensation and mixing. Here, we show that molluscan, foraminiferal, and ostracod assemblages preserved in a condensed sediment core collected off the Po delta at 31 m water depth, still archive information about the composition of benthic communities priorto anthropogenic changes. All three groups exhibit a similar trend in total abundance (density): a gradual increase peaking in a 10 cm-thick shelly lag (approximate to 2-6 kyr BP) with millennial time-averaging, followed by a significant decline in the uppermost 5 cm of highstand silts (representing the past 2 kyr BP) with centennial time-averaging. The molluscan assemblage in the shelly lag integrates across several baseline community states. The assemblage mainly comprises shallow-subtidal filter feeders and soft-bottom infauna, with the bivalve Varicorbula gibba and the gastropod Turritellinella tricarinata dominating and increasing in proportional abundance in the highstand silts. The ostracod and benthic foraminiferal assemblages in the shelly lag are dominated by opportunistic species such as Cytheridea neapolitana, Ammonia beccarii, and Haynesina germanica. In contrast, the foraminifera Nonionella sp. and the ostracod Loxoconcha sp. increase in proportional abundance in the highstand silts, characterised by an increase in filter-feeders among the molluscs, infaunalisation and a decrease in epiphytic species. Although an increase in net sediment accumulation primarily causes the decline in fossil density in the uppermost part of the core, upward changes in the relative abundance of species and functional groups reveal a difference between the baseline and impacted community states. Therefore, the time-averaged fossil assemblage in the shelly lag provides a valuable long-term record of an ecosystem in the region before human impact.
The Zagreb city area is located in a geologically diverse and complex area: on the southern slopes of Medvednica Mountain, the alluvial plains of the Sava River, and on the northern slopes of the Vukomeri & ccaron;ke gorice hilly area. The urbanisation of this relatively large area is an ongoing process, and nowadays, the city's development is proceeding rapidly in unfavourable locations in terms of geohazards, meaning that areas with a possible seismic, flood, or landslide risk are becoming increasingly populated. To achieve sustainable development, geohazards and ground types need to be addressed and assessed for the whole area of Zagreb city as the input for seismic risk assessment. As one step in that direction, existing geological data were reviewed and analysed, and accordingly, geozonation of the Zagreb city area was carried out, differentiating four zones with six geological complexes. Based on the available geological data, we assessed the geohazard processes, ground types, and seismic risk for each differentiated zone and complex, and in that way, a smallscale regional zonation map was developed. Further detailed geo-research of the Zagreb city area is recommended as the city area is relatively large and heterogeneous in terms of geological settings, and detailed geodata are needed to define local geoconditions, geohazards, and ground types. With detailed geo-data, the presented geozonation of the Zagreb city area could be upscaled and directly applied in urban planning. The presented results were used as input for the seismic risk assessment for the research area, and the developed regional map is already being used by the local government.
This study provides the first analysis of the Quaternary pedo-sedimentary complex to understand the succession of palaeosol and sediments, the mechanism of deposition, and the source and age of the material. Each distinctive layer was sampled. Palaeosols are rich in fine-grained components, predominantly silt. Quartz dominates in the light mineral fraction, suggesting that the sediments underwent more redeposition than for typical continental loess. The increase in weathered quartz grains with increasing depth could indicate that the proportion of fluvial sediments has increased compared to the aeolian sediments. Mineralogical and petrographic analyses confirmed the presence of chromite, serpentinite, and serpentinized olivine basalt, indicating an area of origin with ultramafic rocks, which could be the Dinaric ophiolitic zone in the hinterland. The carbonates are polygenetic in origin and consist of equal parts of highly spherical upper Cretaceous rudist limestones, Eocene nummulitic limestones, and low spherical pedogenic carbonate concretions, indicating local transport. According to the OSL dating results, the glacio-fluvial material is either early Weichselian or Saalian in age, while the palaeosol most likely cannot be younger than the Eemian and may even have a Middle Pleistocene age.
New biostratigraphic data obtained by studying ammonoids, calcareous algae, conodonts, and foraminifera from the westernmost part of the East Bosnian - Durmitor mega-unit in northern Montenegro, result in a detailed reconstruction of the Middle - Late Anisian (Pelsonian-Illyrian) subsidence history related to tectonic motions. Two independent times of extension with formation of a horst-and-graben structure and neptunian dikes can be distinguished. During the first phase of extension, a rapid deepening of the footwall block during late Pelsonian times can be recognized. The initial late Pelsonian deepening is characterized by the formation of neptunian dikes in the older Pelsonian shallow-water limestones, which are filled with open-marine red micrite showing a microfacies typical for shallow deepswells. This initial phase is only preserved in the infilling of neptunian dikes and represents the onset of the drowning sequence. The final late Pelsonian depositional deep-swell environment is preserved in a level with stratigraphic condensation, but a deep-water microfacies. The second (late Illyrian) deepening also resulted in the formation of neptunian dikes, a horst-and-graben topography, and the mobilization of mass-transport deposits related to the onset of intense volcanism.
Topsoil geochemistry maps of the city of Sisak were compared with historical maps to explain the geochemistry of the topsoil. Historically, three periods of Sisak's development can be distinguished: 1) the Celtic and Roman period; 2) the Medieval period, and 3) the industrial era during the 20th century. Comparison of the geochemical maps with the historical maps reveals 1) the accumulation of elements in the soil and their preservation over 2,000 years; 2) the influence of infrastructural interventions on the geochemical composition of the topsoil and 3) the high rate of accumulation of potentially toxic elements in the topsoil due to rapid industrialisation on purely arable land.
The Geochemical Atlas of Croatia revealed differences in the spatial distribution of geochemical elements between the Croatian Dinaric coastal region and the Pannonian Basin. In the Pannonian Basin, 1,254 topsoil samples (0-25 cm) were analysed for 27 elements and pH values. This geodynamic unit is characterised by the variability of geological, pedological and land-use-related characteristics. To analyse the geochemical properties of soil above different lithological units, soil types and land use and land cover classes, a discriminant function analysis was performed using the compositional data. The study shows significant geochemical and ecological patterns, with the first two discriminant functions explaining a major proportion of the variability: in the GEOLOGY model, DF1 explains 33.31% and DF2 17.97%; in the SOIL model, DF1 explains 51.59% and DF2 20.22%; in the CLC model DF1 explains 59.85% and DF2 30.30%. The geological model distinguishes between the Quaternary sediments and the older lithological units and highlights alkaline and acidic soil conditions. The soil model shows the effects of fluvial and alluvial deposits, agricultural practices and the underlying geology on soil composition and emphasises the enrichment of essential nutrients and heavy metals in the soils. The land use and land cover model illustrates the anthropogenic influence on agricultural soils and the susceptibility of wetlands to heavy metal accumulation. The results obtained illustrate the complex interaction between geology, the topsoil layer, as well as land use and land cover, providing awareness for environmental management and monitoring, and the need for further geochemical studies of the soils in the Pannonian Basin.
The Late Pleistocene deposits of the East and West Brina Caves near Drni & scaron; have yielded one of the largest collections of alpine marmot (Marmota marmota LINNAEUS, 1758) remains in Croatia. A total of 425 skeletal remains were recovered, with 411 originating from the East Brina Cave. Taphonomic analysis of this assemblage reveals that multiple factors influenced the accumulation and preservation of marmot remains. While natural mortality, most probably, was the primary cause, secondary agents such as predation by small carnivores, particularly martens and foxes, played a significant role. Additionally, a small number of bones bear cut marks, suggesting the occasional human exploitation of alpine marmots by Palaeolithic hunters. Bone surface modifications indicate that many remains were exposed before burial. These finds provide insights into the Late Pleistocene alpine marmot ecological dynamics, and human subsistence strategies in southeastern Europe.
Public health protection, sustainable agricultural practices, and environmental degradation mitigation, all depend on the quality of groundwater. Groundwater quality remains a critical concern in the densely populated cities of Pakistan. Integrated assessment of groundwater quality in an area provides a comprehensive understanding to support effective resource management and policy-making. The focus of this study is to evaluate the ionic concentration of groundwater and subsequent consequences based on twenty-eight groundwater samples acquired from different water schemes in the Gujranwala District, Punjab, Upper Indus Basin, Pakistan. This study analyzes the type of ions, the effect of contamination on agriculture and groundwater contamination-based health risks. Results show that the concentration of major ions in nearly all the groundwater samples lies within World Health Organization (WHO) limits except for arsenic (As). In about 64% of the total samples, the arsenic concentration exceeds the limit recommended by WHO which is 10 mu g/L. The chemical composition of groundwater is influenced by rock weathering according to the Gibbs plot. Magnesium, bicarbonate, and sodium ions contribute to the groundwater's total dissolved solids as indicated by a Piper plot. Most of the water samples are suitable for irrigation purposes, except magnesium hazard values of about 57% substantially impact soil alkalinity. Hazard quotient (HQ) and carcinogenic risk (CR) assessments were also used in the study. The HQ values in the study area lie in the range of 0.012 to 4.97, with an average value of 1.21, and about 57% of samples exceed the toxic risk index values. The CR value range is 5.41667x10-6 to 0.001, indicating a serious health threat to the residents in the area. Prolonged use of arsenic-contaminated water will cause severe health issues for the area's residents. Appropriate remedial and preventive actions should be undertaken to mitigate arsenic pollution in the area.
The scarcity of well data and the inherent subjectivity of geological interpretations often leads to imprecise or oversimplified subsurface models. Traditional interpretation methods struggle with sparse datasets, necessitating the application of advanced machine learning techniques to enhance subsurface characterization. This study leverages artificial neural networks to predict lithology distribution using seismic attributes in the northern Croatian part of the Pannonian Basin System, an area with numerous exploratory wells. Seismic data, long employed as a supplementary interpretation tool, was used to generate a predictive lithological model, overcoming data limitations inherent to well-based methods. A key focus was the volume of shale, a lithological indicator, which was estimated using an extensive set of seismic attributes and processed through innovative data preparation techniques for artificial neural network analysis. A comprehensive artificial neural network based modelling approach was implemented over a 4365 km(2) 3D seismic dataset, targeting Pannonian (Late Miocene-Early Pliocene) sediments deposited in deltaic, turbiditic, and lacustrine environments. Results show that standardization of input data significantly improved model accuracy, particularly in capturing key geological features such as meandering sandstone-filled channels. In contrast, normalization led to unreliable predictions, while raw data substantially underestimated sandstone volumes. Despite its advantages, the method's limitations stem from the inherent uncertainty in the volume of shale estimation and interpreter subjectivity. The approach is well-suited for geological settings with two or three dominant lithologies distinguishable on geophysical well logs. While applicable to coalbearing strata and shale-rich carbonates, its effectiveness in more complex geological settings requires further refinement. The findings highlight the untapped potential of legacy seismic data for geo-energy applications, including hydrocarbon exploration, geothermal studies, and carbon storage.
