We present Sr-87/Sr-86 isotope ratios for similar to 1200 selected soil samples, collected by the GEMAS consortium from grazing (Gr) and agricultural (Ap) soils in Europe with the aim to better understand the strontium isotope distribution in the bioavailable fraction of the top-soil and its potential for provenancing applications. Spatial analysis shows that there is a clear distinction between coastal (<100 km) and non-coastal (>100 km) samples in their variance and that this variance is mirrored in the sodium concentration, suggesting an important but highly variable contribution from seaspray. We present two Sr-87/Sr-86 maps at 25 km x 25 km scale: one based solely on the measured data using a classical kriging approach and one based on a Random Forest model using complementary GEMAS data to predict the strontium isotope composition at the remaining 3000+ GEMAS sampling locations, including appropriate uncertainty assessment. Using a forensic Bayesian likelihood ratio approach, a tool was developed in R to create provenancing likelihood ratio maps. The maps delineate areas of high and low likelihood and allow investigators to direct their resources to areas of interest. For actual forensic case work either the measured or the modelled data can be used as reference data for the overall distribution of Sr-87/Sr-86 values in Europe. (C) 2019 Elsevier B.V. All tights reserved.

Low-density geochemical mapping at continental scale reveals background for emerging tech-critical elements. The demand for a variety of mineral and/or element resources (e.g., rare earth elements, platinum group elements, cobalt, beryllium, lithium...) has increased with the continued consumption in developed countries and the emergence of developing economies. These elements are essential for maintaining and improving future quality of life, including many high-technology yet low-carbon industries. Two factors have been used by the NRC (National Research Council) to rank criticality: the degree to which a commodity is essential and the risk of supply disruption for the commodity. Further, the demand for energy-related minerals has increased, as global energy production diversifies beyond carbon and nuclear-based sources. A critical mineral and/or element is both essential in use subject to the risk of supply restriction and at the same time may induce environmental impacts. To provide a solid base for future generations, it is necessary to identify the spatial distribution of critical elements at a large scale, and additionally to study possible environmental consequences of the increased use of these resources. The average concentration, transformation and transport within and between the different environmental compartments of many chemical elements, which are now key components for the development of new technologies, are poorly known. Here we investigate three critical elements (Sb, W and Li) using low-density

Sediments from two boreholes drilled in the Drava and Sava depressions were analyzed to determine the origin of the elevated arsenic (As) concentrations in groundwaters in eastern Croatia. The composition of the sediments was investigated by total chemical analysis and sequential extraction. In addition, groundwater samples were taken from eight producing wells, and hydrochemical and trace element and As speciation analyses were performed. The concentrations of As in the sediment were high (up to 471 and 65.1mg/kg, in the <0.065mm fraction in the boreholes in the Drava and Sava depression respectively) supporting the hypothesis proposed in a previous hydrochemical study that the Middle and Upper Pleistocene sediments are the main source of As in eastern Croatian groundwaters. Mineralogical and chemical analyses showed that sediments from the Drava and the Sava boreholes differed, supporting different origins of the sediments in the boreholes concerned: the provenance of PVc-3 sediments being the Alps, and of G1 sediments, the Bosnian mountains. In both boreholes, the large amount of As was bound to amorphous Fe and Mn (hydr)oxides (on average 32% and 60% in boreholes PVc-3 and G1 respectively). Sediment and groundwater analyses indicate that reductive dissolution of iron (hydr)oxides and concomitant release of sorbed or co-precipitated As into the groundwater is ready to occur. Since the groundwaters in eastern Croatia are generally anoxic and reducing conditions, in which S2− and Fe2+ are stable, prevail the concentration of As released by reductive dissolution of iron (hydr)oxides may be controlled by the secondary formed sulfides which could act as a sink rather than as a source of As in the groundwater. Depending on local geomorphological and hydrogeochemical conditions, in the zones with a longer groundwater retention time, pH dependant As desorption from iron (hydr)oxides can occur and other trace elements such as Mo may become mobile.

The Šarengrad loess section is located on the south bank of the Danube River in the easternmost part of Croatia. The published lithostratigraphical results including grain size, total organic content, calcium carbonate content and luminescence dating results are complemented by geochemical (content of major and trace elements and acidity) and magnetic susceptibility (κ) studies. Throughout the section, four palaeosols are intercalated in the loess. The oldest, hydromorphic one is covered by laminated alluvial sediments and loess. The second palaeosol is an argillic dark brown soil with the highest κ value of the profile, and the other two palaeosols are brownish and less developed. Geochemical characteristics and MS signals of the palaeosols explain both the main characteristics and degree of pedogenesis. Palaeosol horizons could be clearly distinguished from loess based on the content of major and trace elements and on weathering coefficients, such as Ba/Sr, and (CaO+Na2O+MgO+K2O)/Al2O3. IRSL age estimates of 86.6±8.6 and 55.3±5.5ka indicate that most of the middle and upper pleniglacial loess record is missing at the Šarengrad section. However, the loess/palaeosol sequence at Šarengrad has a very detailed record correlating with MIS 4–5.

In order to examine the extent of the As enrichment and the factors influencing this enrichment in the groundwater of Eastern Croatia, groundwater samples were collected from 56 production wells in two counties, Osijek-Baranja and Vukovar-Srijem, suspected to be more affected. Hydrochemical analyses were performed at all locations including in situ As speciation at 32 locations. Arsenic was detected in 46 out of 56 groundwater samples with total As concentrations up to 491μg/L. Thirty-six of the studied wells yielded groundwater with total As concentrations that exceeded the WHO Maximum Contaminant Level for arsenic in drinking water of 10μg/L. Only inorganic As species were detected with arsenite As(III) as the predominant form. The spatial distribution of As in the groundwater was significantly linked with geological, geomorphological and hydrogeological development of the alluvial basin of the Drava and Sava rivers. The most probable groundwater As sources are deeper sediments from the Middle and Upper Pleistocene. The results obtained suggest that biogeochemical processes controlling As concentration in the groundwater are complex and location-specific. Reductive dissolution of Fe oxides, desorption of As from Fe oxides and/or clay minerals as well as competition for the sorption sites with organic matter and phosphate could be the principal mechanisms that control As mobilization. The extent of those processes vary in the different parts of the Drava and Sava depressions and could be linked to different site related parameters, such as lithology, mineralogy, local hydrology and hydrogeology; thus different processes of As mobilization have been proposed for the different types of water in relation to groundwater evolution.

In Eastern Croatia, impressive loess-palaeosol successions up to 30m thick are exposed along the steep cliffs of the Danube River between Zmajevac and Šarengrad. The Croatian loess record provides an excellent high-resolution archive of climate and environmental change, providing evidence for the interaction between accumulation and erosion of aeolian and fluvial sediments during the Middle and Late Pleistocene. Sedimentological and pedological investigations, including granulometry, carbonate content and total organic carbon content, and infrared optically stimulated luminescence (IRSL) dating were carried out on samples collected from the loess sections at Zmajevac, Erdut and Šarengrad. The loess successions are intercalated by at least four palaeosols or pedocomplexes, which very likely correlate with Middle and Upper Pleistocene interstadials and interglacials. In all sediment successions investigated, alluvial sediments are intercalated in the loess deposits, indicating periods of fluvial activity. The stratigraphically youngest alluvial sediments are exposed at the Erdut section. Loess sandwiching these alluvial sediments yielded IRSL age estimates of 61.5±6.2 and 53.8±5.4ka. The IRSL age estimates give evidence for periods of increased accumulation of dust during the middle and late pleniglacial, correlating with oxygen-isotope stage (OIS) 3 and OIS 2, respectively, during the penultimate glaciation and at least the antepenultimate glaciation. However, it is likely that IRSL age estimates >60ka are underestimated.

Middle Triassic arc-related extensional tectonics in the western Tethys generated a complex pattern of intra-and backarc basins. We studied volcano-sedimentary successions of subsided continental-margin blocks (Mts. Zumberak and lvanscica) and of dismembered incomplete ophiolite sequences interpreted as remnants of a backarc basin (Mts. Medvednica and Kalnik) in northwestern Croatia. We dated the successions with radiolarians, conodonts, foraminifers, algae, and sponges.The continental margin experienced a phase of accelerated subsidence in the late Anisian that was approximately coincident with the onset of intermediate and acidic volcanism; pelagic sediments with volcaniclastics accumulated atop subsided carbonate platforms. These relatively shallow basins were later infilled completely by prograding platforms in the late Ladinian-Carnian. In the backarc basin, sea-floor spreading initiated near the Anisian-Ladinian boundary and continued into the late Carnian. Pillow basalts were erupted and interlayered with radiolarian cherts and shales.The studied area was a part of a larger Triassic arc-backarc system preserved in the southern Alps, Alpine-Carpathian Belt, Dinarides, and Hellenides. Volcano-sedimentary successions of Mts. Medvednica and Kalnik are relics of the Meliata-Maliak backarc basin. In comparison to other previously dated oceanic remnants of this system, the longest continuous sea-floor spreading is now documented in one restricted tectonic unit.

The Middle Jurassic (uppermost Bajocian-lower Bathonian to upper Bathonian-lower Callovian) radiolarian cherts in the Medvednica Mt (NW Croatia) have a high content of SiO2 (average 90.87 %). Most of the silica is of biogenic origin as is indicated by a high Si/Si+Al+Fe+Ca ratio (0.83-0.97). The Al/Al+Fe+Mn ratio (average 0.59) and relatively low contents of Fe and Mn suggest that the sedimentation of the radiolarian cherts was not influenced by hydrothermal volcanisms. The high correlation coefficient between the lithophile elements Ti, K, Al, Th, Zr, Hf and Rb implies that the detrital component in radiolarian cherts for the most part has a terrigenous provenance. The MnO/TiO2 ratio and La-n/Ce-n vs. Al2O3/(Al2O3+Fe2O3) diagram show that the investigated cherts were derived from two different, but not necessarily strongly separated, sedimentation areas: (1) continental shelf and slope or marginal sea, and (2) deep ocean floor, trench or basaltic plateau. According to the proposed sedimentation model the radiolarian cherts in the Medvednica Mt were deposited in a relatively narrow basin. The detrital material was derived from two source areas: (1) from a continent (terrigenous input) and (2) from an accretionary wedge (undifferentiated magmatic arc-like input). During the Late Jurassic-Early Cretaceous the radiolarian cherts were incorporated into the tectonic melange (accretionary prism) along with other fragments: Triassic radiolarian cherts and carbonate rocks; Jurassic shales, siltites and sandstones and basic and ultrabasic magmatic rocks.

Scinderella scopuliformis nov. gen., nov. sp. is identified in the Anisian (Middle Triassic) reef limestones from the Belski dol quarry (lvanscica Mt., NW Croatia). The new alga is characterised by claviform thallus, curved in the basal part, and very narrow central cavity. Thallus is often disintegrated into fragments. Laterals swell from a thin basal part, and have uniform (rarely slightly increasing) diameter along most of their length. Distally, they are flattened and probably touch each other, forming an irregular cortex. Laterals are arranged densely in close whorls and oblique to the longitudinal axis. Euspondyl arrangement is readily visible in the proximal part of the laterals, but distally, the arrangement seems more or less irregular, i.e. ruffled (Lat. scindere = ruffle, dishevel) and resembling a broom (Lat. scopulae = small broom; forma = form, shape). (C) 2002 tditions scientifiques et medicales Elsevier SAS. All rights reserved.

The analysed Triassic (Illyrian, Lower Fassanian, Upper Carnian) radiolarian cherts on Zumberak, Ivanscica, Kalnik and Medvednica Mts (NW Croatia) are rocks with high SiO2 content (mean >90%) and the major part of silica is of biogenic origin. Besides this siliceous component, two others stand out in the radiolarian cherts. One of them is detritic (terrigenous input) and it consists mainly of Al, Ti, K, Zr, Hf, Cr, Th, Rb, Nb and Sc. The other, hydrothermal one, is composed of Fe, Mn, P, Cu, Pb, Zn, Ni, Co and Sr. The terrigenous component is a significant REE carrier. The radiolarian cherts on Kalnik and Medvednica Mts show a positive Ce-anomaly (Ce/Ce*) which indicates a sedimentation in a narrow trough relatively close to the continent. The negative Ce-anomaly on Zumberak and Ivanscica Mts suggests a reduced terrigenous input. The radiolarian cherts in the last mentioned areas are sedimented directly onto the dolomites and limestones of the carbonate platform. This means that the terrigenous input was probably weaker, because of the width of the disintegrated carbonate platform (larger distance to the continent) or because of a topographically higher position (bypass of fine terrigenous material) with respect to Medvednica and Kalnik.