Institute for Geological and Geochemical Research

The Iron Gates gorge, where the Danube River cuts through the Carpathian Mountains, represents a key corridor for understanding fluvial dynamics in Central and Southeast Europe. This study presents new insights into the formation and Quaternary evolution of the Lower Danube Gorge through high-resolution morphometric analyses and relative and absolute dating of terrace sequences within the gorge and the downstream alluvial plain.The earliest fluvial terraces, located at elevations between 270 and 320 m, mark the initial phase of river incision. Terraces T8 to T5 formed during this period and are correlated with mid–late Pliocene fine alluvial deposits and late Pliocene–early Quaternary coarser alluvial fan sediments downstream. The transition from upper (T8–T5) to lower terraces (T4–T1) in the gorge mirrors a comparable sequence in the Danube lowlands, where 7–8 alluvial terraces are identified, representing the shift from upper deltaic and alluvial fan deposits to the lower Danube plain.This longitudinal correlation highlights a regional change from lateral fluvial erosion and downstream vertical aggradation to dominant fluvial incision and terrace formation during the Middle–Late Quaternary, influenced by ongoing tectonic uplift and glacial–interglacial climate cycles. Fossil assemblages support a Late Pliocene–Early Quaternary age for the upper terraces, while newly obtained OSL dates for the younger terraces at the gorge exit (T3–T1) correspond to Marine Isotope Stages 3–1.The results reinforce the antecedent drainage model for the Danube at the Iron Gates, suggesting episodic incision superimposed on an actively uplifting landscape.Acknowledgments: This research was funded by the ChronoCarp project (Contract no. 760055/23.05.2023, project code CF 253/29.11.2022, PNRR-III-C9 2022-I8).

Olivine, as the first crystallization product from basaltic melt, provides important information about the magma origin. Here we provide a detailed textural, major and trace element, and noble gas isotope compositional data for a alkaline basalt suite from the Persani volcanic field (PVF) of the Carpathian-Pannonian Region. This is the youngest monogenetic volcanic field (1,3 Ma - 0,6 Ma) formed in a geodynamically still active zone. A descending, vertical lithospheric slab result in frequent earthquakes, whereas nearby, another young volcanic system is found (Ciomadul). The alkali basalt magmas were formed due to decompression melting in the asthenosphere, at 60–80 km depth.Thus, olivine composition can be used to characterize the nature of asthenospheric mantle in a postcollisional area. Noble gas isotope ratios, especially the 3He/4He, are sensisitve indicators of the mantle composition. There are relatively comprehensive data on mantle xenoliths, however, only sporadic data are from olivine crystals of basalts. This is due the challenge of such studies, because of the need of clean olivine separates and detection of low amount of gases from the primary fluid inclusions.In the Carpathian-Pannonian Region, we firstly detected noble gas isotopes from phenocrysts of basaltic rocks. We sampled different eruption products of the PVF from different eruption episodes. Following a multi-step sample preparation process, we analysed the olivine separates with noble gas mass spectrometer. Petrographic characteristics and major element composition of most olivine phenocrysts suggest crystallization from primary basaltic magma. Due to fast magma ascent, the olivine crystals preserved the original noble gas isotope ratios in their primary fluid inclusions in most samples.We got relatively low, ~2-5 R/Ra values (3He/4He of the sample divided by 3He/4He of the atmosphere) which are lower than the R/Ra values obtained from the olivine and pyroxene crystals of lithospheric mantle xenoliths in the PVF alkaline basalts (~6 R/Ra), suggesting geochemical differences between the local asthenospheric and lithospheric mantle. Our results are also significantly lower than the usual R/Ra of the depleted mantle (~8 R/Ra). The low values can be explained by metasomatism of the asthenospheric magma source region with crustal fluids during former subduction and/or 4He addition to the asthenosphere from the radioactive decay of U and Th originated from the subducted lithospheric slab. Another possible explanation could be the lithologic heterogeneity of the magma source region. The Mn, Ca and Zn content of olivine autocrysts also indicate the presence of recycled crustal material in the mantle source, in agreement with the noble gas isotope compositional data. Our results suggest that in a postcollisional setting the asthenosphere is contaminated by recycled crustal material and subduction-related fluids.

In areas of multiple exposure-burial histories the use of two cosmogenic radionuclides (CRN) with different half-lives allows to reveal the disequilibrium between CRN concentrations and provide a better understanding of landscape evolution. This study aims to quantify bedrock denudation rates in the Western Mecsek Mts (southern Pannonian Basin), a low-elevation hilly area that is currently being exhumed from under its loess cover deposited during the Quaternary glaciations. Concentrations of 10Be and 26Al were measured in samples taken from flat, soil-covered ridge tops and stream sediments from several small river catchments composed of Permian and Triassic sandstones and conglomerates. Low 26Al/10Be ratios are indicative of unsteadiness caused by significant past burial of the bedrock surfaces. A Monte Carlo (MC) model was developed to reveal the temporal evolution of the loess cover as a function of glacial-interglacial climate, and to determine the true rate of bedrock denudation accounting for both loess-covered periods with shielding and zero erosion as well as phases of exposure and bedrock denudation during periods without loess.Our model showed that higher-elevation catchments and ridges were exposed for 40 to 85%, while lower-elevation areas were uncovered for less than 30% of time during the last 1 Ma. The modelled time integrated bedrock denudation rates were similar for the ridge crests and basin-averaged samples suggesting a steady relief. However, a well-expressed difference was found between the areas spending most of the time loess covered and the less covered group with mean integrated denudation rates of 5±5 m/Ma and 19±8 m/Ma, respectively. Single nuclide 10Be denudation rates overestimated the modelled, time-integrated denudation rates by a factor of ~1.5 for the more exposed group and by a factor of ~13 (up to >30) for the mostly covered areas. These rates, especially the latter, are slower than published values for similar climatic, tectonic, and topographic settings. If the simple, single nuclide 10Be approach was used, these differences would have remained hidden, and the true lowering rate of bedrock would have been overestimated by a factor that increases with the shielding time.This is the first study quantifying the influence of past loess covers on CRN concentrations in bedrock and to estimate the denudation rates corrected for this shielding. Our findings reveal that the steady-state assumption of the CRN concentrations may also be violated in small, non-glaciated catchments without intermittent sediment storage. Where single-nuclide 10Be denudation rates are higher than sediment-trap estimates, the shielding effect of past sediment cover (such as loess) could also explain the discrepancy. Accordingly, we recommend the use of the paired 26Al/10Be approach to test the presumption of cosmogenic nuclide equilibrium not only in large catchments and formerly glaciated areas, but also in settings where past sediment cover may have lasted long enough to lower the CRN ratio.Funding: PURAM, Mecsekérc Ltd., NKFIH project FK 124807. Sample processing: Cosmogenic Laboratories of Budapest (n=16) and of the University of Edinburgh (n=4); AMS measurements: ASTER, Aix en Provence (n=16) and SUERC, Glasgow (n=4)

Constraining the surface uplift history of mountain belts is difficult because – due to erosion – the surface is made of ever-changing rock levels and changes in surface elevation over time can only be indirectly inferred. Here we present 26 Al/ 10 Be burial ages of siliceous fluvial sediments that were deposited into karst caves as a proxy for surface uplift of the Eastern Alps. We present a consistent and homogenized dataset for the Eastern Alps that includes 31 new burial ages, together with 36 previously published burial ages that have been recalculated. Most of the sampled caves are now inactive and are located at between 600 and 2400 m a.s.l.. The cave sediments were deposited when they formed at the phreatic-vadose transition at base level, which we assume has remained at constant elevation through time. The samples are from regions that were variably affected by Pleistocene glaciation. Cosmogenic 21 Ne concentrations in samples from 20 caves record prolonged and complicated Neogene exposure. Generally 21 Ne/ 10 Be burial ages cannot be used to determine cave level ages, but the 21 Ne data preserve a record of denudation and burial since the Oligocene. The homogenized dataset of 67 of 26 Al/ 10 Be burial ages allows us to infer 1200–1500 m of surface uplift for the Northern Calcareous Alps and ~ 500 m in the transition zone towards the Pannonian Basin in the east during the last 3–5 Ma. The fastest surface uplift rate is estimated for the ranges around the Salzach valley (407 ± 34 m/Ma), followed by the Gesäuse region (357 ± 19 m/Ma). For the Dachstein Massif, the Hochschwab and the Schneealm regions we interpret post-Miocene surface uplift rates of 224 ± 21 m/Ma, 272 ± 12 m/Ma and 283 ± 13 m/Ma, respectively. Uplift rates decrease to the east: the Mur valley and the Semmering uplifted at 137 ± 11 m/Ma and 125 ± 3 m/Ma, respectively. The data support the notion that much of the topography of the Eastern Alps was created in the last 5 Ma rather than the 30 Ma timescale that previous studies have suggested. The long wavelength nature of the uplift over formerly glaciated and unglaciated regions implies that the surface uplift was caused by sub-lithospheric processes and that climatic factors played only a minor role.

<strong class="journal-contentHeaderColor">Abstract.</strong> Stable isotopes of hydrogen and oxygen in precipitation (<em>&delta;ₚ</em>) are important natural tracers in wide range of environmental applications (e.g., the exploration of the water cycle, ecology and food authenticity), yet observational records commonly contain gaps, although applications in hydrology and earth science frequently require complete cases. Eight imputation approaches were benchmarked using monthly <em>&delta;ₚ</em> time series from Austria, Slovenia, and Hungary. Uninterrupted periods were selected, and monthly data were masked site-wise with an increasing degree of missingness, removing 1 to 32 % of the data using bootstrapping. The imputation performance of the following methods was assessed on the masked monthly data using the mean absolute difference and root mean square error between the observed and imputed values for primary and secondary isotopic parameters: Last Observation Carried Forward, Linear Interpolation, Spline Interpolation, Stineman Interpolation, Kalman Smoothing, Moving Average Imputation, Sinusoidal fit, and a spatial proximity-based imputation (SPbI) approach introduced in the present paper. SPbI estimates missing &delta;ₚ values using the mean of altitude-corrected &delta;ₚ data from within a predefined search radius. Across masking levels, SPbI was the most accurate and least prone to amplitude damping in <em>&delta;ₚ</em> records. Sinusoidal imputation remained robust under increasing missingness but has shown a tendency of reducing extremes, indicating amplitude loss in both <em>&delta;ₚ</em> and d-excess. Spline performed worst overall with the rest performing similarly up to ~16 % masking beyond which their performance deteriorated. A sensitivity analysis using non-cumulative 50-km distance bands up to 400 km showed that SPbI errors increase with distance; beyond ~250 km, mean errors approach those of the sinusoidal method, making the sinusoidal&mdash;or even the simpler linear interpolation&mdash;a viable alternative when proximal observations are sparse. The benchmarking results recommend the use of SPbI where station data are available within 250 km distance, and the sinusoidal or linear approach otherwise.

During the last glacial period (~118 to 11.7 ka), the Arctic has been characterized by a major redistribution of flora and fauna as a consequence of extreme climatic fluctuations, with associated glacial advances and retreats, sea-level changes, and shifting sea ice extent. In the high-latitude regions of Northern Europe that are currently subject to rapid climate warming, we lack a comprehensive understanding of faunal biodiversity in the last glacial period due to the extreme rarity of preserved organic remains. Here, we present a stratified sediment deposit with a diverse faunal composition preserved in a bone-bearing layer in Arne Qvamgrotta, part of the Storsteinhola cave system (68.10° N 16.38° E) in Northern Norway. Chronological analyses of sediments and bones including radiocarbon, optically stimulated luminescence, uranium-thorium, and phylogenetic dating place the faunal assemblage in Marine Isotope Stage 5a (MIS 5a, Odderade interstadial, ~85 to 71 ka). Combining comparative osteology and bulk-bone metabarcoding, we identify 46 taxa, including mammals, birds, and fish, with several species not previously found in Fennoscandia. The fauna implies a nonanalogous cold-adapted coastal community, with close proximity to sea ice and nearby freshwater bodies. Mitogenome analyses of a subset of taxa identify extinct lineages which attest to a lack of habitat tracking and the absence of a local refugium during the subsequent fully glaciated periods. This faunal record demonstrates long-term faunal dynamics and coastal environmental conditions during MIS 5a in the European Arctic.

The bacterial strain PA1-206BT is a Gram-stain-negative, aerobic, non-motile and non-spore-forming bacterium with an irregular rod shape. It was isolated from a tree wound exudate of the Populus fremontii trunk in the Sonoran Desert (USA), and its taxonomic position was investigated by a polyphasic approach. Strain PA1-206BT grew optimally at 28–30 °C and from pH 6 to 10 without NaCl. Based on 16S rRNA gene sequence analysis, this isolate showed only 96.0% sequence similarity to the type strain of Pseudogemmobacter hezensis and similarity of 94.4–95.7% to other species of the genus. Phylogenetic analysis based on whole-proteome comparisons placed strain PA1-206BT within the genus Pseudogemmobacter but, on a distinct branch, clearly separated from its closest relatives. The major isoprenoid quinone of the strain was ubiquinone Q-10. The predominant fatty acids (&gt;5%) were C18:1 ω7c, C16:0 and 11-methyl-C18:1 ω7c. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminolipid and two unidentified phospholipids were present. The assembled draft genome of strain PA1-206BT had 115 contigs with a total length of 4.5 Mb and a G+C content of 67.4 mol%. The overall genome-related indices (average nucleotide identity &lt;80.4%, average amino acid identity &lt;70.6%, digital DNA–DNA hybridization &lt;21.6%) with respect to close relatives were below the corresponding threshold to demarcate bacterial species. Strain PA1-206BT (=DSM 115559T=NCAIM B.02680T) is suggested as the type strain of a novel Pseudogemmobacter species, for which the name Pseudogemmobacter sonorensis sp. nov. is proposed.

Keywords: precipitation, river water, subsurface water, climate conditions, δ18O, δ2H, 14C groundwater agesThis study presents a comparative isotopic hydrological assessment of two continental catchments: the Koppány Stream in Hungary and the Ledava Stream in Slovenia. Stable oxygen (δ¹⁸O) and hydrogen (δ²H) isotopic signatures were monitored to investigate water source contributions, flow paths, and residence times under varying hydrological conditions.The Koppány catchment, located in southwestern Hungary, spans approximately 660 km², with dominant agricultural land use and patches of natural forest. The Ledava catchment, extending across the Hungary-Slovenia border, covers 1,940 km² and shares similar climatic characteristics but features more lowland areas. Annual precipitation averages are 630 mm for Koppány and 798 mm for Ledava.From 2022 to 2024, δ¹⁸O and δ²H measurements were conducted on precipitation, surface- and subsurface water (shallow and deep groundwater) in both catchments. Results show comparable isotopic values in precipitation across the two sites. In both catchments, river and groundwater exhibit smaller isotopic variability than precipitation. Subsurface water is more depleted than river water and precipitation, especially in deeper aquifers.In the Ledava catchment, river water displays less negative isotopic values than mean precipitation, with an upstream (Polana) station showing slightly enriched signatures compared to a downstream (Čentiba) station. Shallow groundwater aligns well with river water isotopic composition, while deeper groundwater is more depleted but not as strongly as in the Koppány catchment. In the Koppány catchment, the seasonality of the stable isotopes in the streamwater was compared to the amplitude of precipitation. The study revealed the effect of the reservoirs on the evaporation and the presence of waters of different origins in the stream.The pattern observed in the δ¹⁸O and δ²H values indicates that the deep groundwater infiltrated under colder climatic conditions than today, likely during glacial conditions. δ¹⁸O and δ²H values of deep groundwaters were detected as more negative than those of shallow (young) groundwaters. Accepting the correlation between stable isotope composition of Hungarian groundwaters and temperature, deep groundwaters have infiltrated in 6 to 8 oC colder climate than the current temperature. Their Ice-age infiltration is supported by the oldest 14C groundwater ages of 16 to 21 ka, close to the Last Glacial Maximum (LGM). Their 3H content being lower than the detection limit (

The Perşani Volcanic Field (PVF) is the youngest and the smallest (as territory and volcano numbers) manifestation of mafic intracontinental monogenetic volcanism in the Carpathian-Pannonian Region, eastern-central Europe. Eruptions of basaltic magmas took place behind a slab roll-back segment of the Vrancea zone between 1.25 Ma and 0.65 Ma. It is still a geodynamically active region, where further volcanic activity cannot be excluded. The PVF provides an excellent area, where wide range of products of basaltic volcanism can be observed in a restricted area and therefore it can play a significant role in education and geotourism. Lava flows and shallow intrusions are represented by columnar as well as platy and curvilinear jointed basalts. There are scoria cones with unique exposures of proximal and distal deposits and maar structures with hydrovolcanic pyroclastic successions including ballistic impact sag structures. In addition, large number of mantle-derived ultramafic xenoliths are found both in the basalt lava rocks and also in the maar volcanic pyroclastic rocks. The well-preserved volcanic structures form unique geoheritage and in combination with historic and cultural heritage this offers a potential to establish a geopark, where visitors can learn about volcanic rocks and processes. This study summarizes the initial comprehensive findings of the regional geosite inventory and evaluate the volcanic geosites. The geosite assessment was carried out by combination of two widely used quantitative methods. The results highlight the current status of the volcanic geosites, demonstrating their strengths and weaknesses from touristic, educational, and scientific perspectives. Based on the assessment results, the most representative 10 volcanic geosites were selected and described in detail. Finally, the preliminary assessment also provides new data for territorial management and tourism development, as well as regional geoconservation plans, which could help to establish a potential UNESCO Global Geopark project in the near future.