Geochemical fingerprinting of sediment sources typically assumes that tracer concentrations are conserved from source to mixture, a condition rarely met in open systems subject to selective weathering, mass loss, and selective sorting. We develop a compositional data analysis (CoDA) framework for geochemical tracer selection that operates in log-ratio space, avoiding the incoherence of absolute-concentration methods and the invalid mass-conservation assumption of range tests. The framework combines geochemical screening for element conservatism, a standardised variation matrix to confirm compositional independence, and a two-stage OLR balance selection based on a Bayesian posterior predictive range test and a signal-to-noise criterion. It is evaluated on terra rossa soils from the Istrian Peninsula and Susak Island (Croatia). Terra rossa are carbonate-hosted soils developed from mixed siliciclastic parent material with significant loess- and flysch-derived contributions, making them ideal test cases for open-system provenance analysis. Endmember modelling with CoDA-selected tracers is benchmarked against independent heavy mineral (HM) assemblage modelling on the same profiles. Despite optimal tracer selection, geochemical modelling systematically overestimates flysch contributions, attributing ∼4% flysch even to a palaeosol on Susak Island, where no flysch outcrops exist, and mineralogy assigns essentially 100% loess contribution (mean flysch fraction below 1%). The Susak Island palaeosol provides a uniquely constrained natural control: the island contains no flysch outcrops, and the palaeosol rests directly on carbonate bedrock at the base of a thick loess sequence, making its aeolian origin geologically unambiguous. Log-ratio transformation is a necessary but insufficient condition for reliable provenance modelling in open systems. Mineralogical grain-count data, which enable modelling of variables invariant to weathering and sorting, should serve as the primary benchmark wherever source HM concentrations differ substantially, mass conservation cannot be assumed, or pedogenic modification is intense.

Two marine carbonate-rich sediments were studied to gain insight into the role of carbonate minerals of different origin in the distribution and occurrence of metal(loid)s. Successive fractions of surficial sediments were separated according to size (<8 m, <4 m, <2 m, <1 m and <0.45 m) and the changes in their properties and multi-element composition were investigated. Both sediments showed low levels of metal(oid)s, as a result of their high carbonate content. The size-related concentrations of elements in the sediment fractions varied according to the ratio of carbonates to aluminosilicates, which was governed by the carbonate origin. In sediment with detrital calcite, the coarse-grained calcite particles were efficiently removed already from the <8 m fraction, leading to a prevalence of aluminosilicates and a significant size-dependent increase in the concentrations of most elements in finer fractions. In sediment with authigenic aragonite, fine aragonite particles were present in all fractions, diluting the aluminosilicate component and lowering the content of metals. A significant increase in the concentrations of most metals occurred only in the finest fraction (<0.45 m), where the content of carbonates eventually decreased. Similar size-dependent trends of Sr and U in sediment with authigenic carbonates indicated the important role of aragonite precipitation in their sequestration. The redox sensitive elements As, Mo, Sb and U were significantly associated with sedimentary organic matter and affected by Fe and Mn cycling under reducing conditions, prevailing in the investigated sediments. Fractionation by particle size revealed significant differences in the sequestration and behavior of the elements in these seemingly similar carbonate sediments, which remain undetected when considering the bulk sediment.

The quantification of the proportion of end-members in polygenetic soils and sediments is usually based on grain size distribution and geochronological, geochemical and mineralogical data. Most of these techniques have inherent disadvantages, such as selective weathering of the source rock, hydraulic sorting of the sediment during transportation, fertility bias, selective dissolution of mineral components and authigenic formation of new mineral phases during pedogenesis. These processes change the original information, i.e. the geochemical, mineralogical and geochronological information of the source, and thus lead to distortions of the modelling results. An approach to quantifying end-members in soils is presented here. It is based on the analysis of heavy mineral assemblages in potential source rocks and in the soil in question. Based on the heavy mineral data, new variables are modelled that are transport- and dissolution-invariant and, as such, preserve the information inherited from the source. The values of these newly modelled variables in the source samples serve as endmember values, based on which the proportions of end-members in the samples of interest are unmixed using the MixSiar package in the R environment. The model was tested on polygenetic terra rossa soils along the eastern Adriatic coast. A total of 55 soil samples were analysed from 14 different soil profiles, additionally 100 potential source samples were analysed as well. The study area was divided into three regions: the northern, mid and southern Adriatic. Since the Adriatic shelf is predominantly fed by Alpine/Apennine and Albanian material, this is also reflected in the soil composition, whereby the Dinaric, i.e. flysch component, is only locally significant. This indicates that the aeolian transport of shelf sediments occurred over quite short distances during periods of low sea level. In addition, modelling has shown that the composition of the shelf in the southern Adriatic was probably different in the past, with a very limited supply of Albanian material predominating in the recent and subrecent southern shelf, indicating a different tectonic/oceanographic setting for this shelf area. Finally, the results indicate the general importance of aeolian sediments for soil formation along the entire eastern Adriatic coast.

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 Minjera bauxites are the first analysed and mined bauxites in the world. They are a group of pyritised bauxites situated in northern Istria, developed during the subaerial exposure phase which marked a major part of the Late Cretaceous and Palaeocene in northern Istria. In this study, the morphology, petrography, mineralogy, geochemistry as well as stable sulphur isotopes of the D-1 and D-15 deposits from Minjera were studied, as well as the evolution of their bedrock and cover. This study found that those two deposits differ in morphology, mineralogy and geochemistry as a consequence of their different palaeotopographical positions, with the D-1 deposit located at a higher position at the time of its formation compared to D-15, which led to the higher degree of leaching and desilicification in the D-1 deposit. The pyritisation in the studied deposits was a multi-phase process, which began with the deposition of framboidal pyrite and micrometre-sized anhedral pyrite, over which colloform pyrite was precipitated. This indicates that the solutions were initially supersaturated with iron sulphide, saturation of which subsequently changed, as finally euhedral, dendritic and acicular pyrite were deposited, indicating undersaturated conditions. The final stage was marked by deposition of pyrite veins. This formational sequence of pyrites is also supported by stable sulphur isotopes, as the δ34S values exhibit a wide range from -40.86 to 2.32 ‰, where lower values indicate an open system with an unrestricted sulphate supply in which supersaturated conditions could have been achieved, while the higher values indicate a change towards a closed system with limited sulphate supply. The organic matter necessary for microbial sulphate reduction was derived from the marshy environment established atop of the bauxite. The initial flooding started in the Palaeocene, with the first part of the sequence being deposited under lacustrine conditions, which changed towards fully marine with the deposition of Foraminiferal limestones.

The potential impact of the open coal depository and the slag disposal of the Plomin thermal power plant (PTPP) on the composition of the surrounding soils was investigated. A comprehensive approach taken included analyses of mineral composition, potentially toxic element content, their bonding properties, distribution to specific geochemical fractions in the soil and investigation of the soil organic petrology and geochemistry. The Cambisols at two sampling sites exhibited a coal dust -covered upper horizon, which led us to consider these soil profiles as Technosol over Cambisol. For practical reasons, we have used the terms Technosol and Cambisol for the upper and lower parts of these profiles respectively. These formations were developed by the long-term deposition of coal dust and slag particles originating from the open coal depository and slag disposal of the PTPP, and widespread wind dispersion. The Technosols, characterized by higher concentrations of lignite and lignite-subbituminous coal, showed elevated levels of C and S. Analysis of the slag sample revealed a mineral composition of mullite, tridymite, graphite, haematite and an amorphous phase, indicating material formation by high temperature coal combustion. The PTPP was identified as the main contributor to the elevated concentrations of Hg, Mo, Se, Sb, U and Cd. The Technosols showed a significant enrichment in Hg, Sb, Se, Mo and U compared to the Cambisols. In the Technosols, elements such as As, Cr, Cu, Fe, Ni and Zn were primarily associated with the organic and Fe-Mn fractions, whereas in the Cambisols these elements, (with the exception of Cu), are mainly associated with the organic and residual fractions. Cadmium, Mn and Pb were predominantly bound to the carbonate and FeMn fractions in all the analyzed samples. The non -residual fraction has been proven to be the predominant repository for As, Zn and Ni in the Technosols and slag, and for Mn, Zn and Cd in the Cambisols. The total content of C and S in the soils and their ratio (C/S) confirmed the higher contamination of soils in the vicinity of the PTPP with coal material. Detection of the coke and soot in the slag sample substantiated its composition as bottom coal ash. In addition, the presence of the bottom coal ash particles in the Cambisol underlined the airborne dispersal of the slag and its integration into the soil composition.

Glauconite formation is generally perceived as a process occurring in deep-marine environments, but in the last few decades its formation in shallow-marine environments is progressively more recognised and utilized for palaeoenvironmental reconstructions. One such example is the lower Kimmeridgian to upper Tithonian Zlatni Rt palaeosol, which is especially unique since the glauconite occurrence is hosted within the palaeosol material. Micromorphological, mineralogical, and chemical characterisation of the palaeosol was followed by the detailed analysis and description of glauconite using SEM-EDS, XRPD and FTIR. In addition, lithofacies and micropalaeontological analyses have been carried out on the carbonate succession under- and overlying the palaeosol in order to better understand the stratigraphic framework. The palaeosol formed in hydromorphic conditions, in contact with brackish to marine porewater, and is composed of mixed-layer illite–smectite, illite, kaolinite, vermiculite, pyrite, marcasite and titanium oxides. The glauconite was formed after the formation of the palaeosol, predominantly through fixation of potassium and iron into illite and mixed–layer illite–smectite, while part of the glauconite formed authigenically, with evidence for microbial influence. The glauconite is present in a more oxidised and more reduced form, which alternate together with pyrite in veins, indicating fluctuations in the redox potential. This can be connected to the variations in the supply of organic matter and sea-level oscillations during the initial stages of the transgression. Glauconite formation was locally followed by the formation of transgressive breccias and a complete drowning of the area. During this phase lagoonal Kirmenjak limestone was deposited throughout the area, while in the palaeosol coarse pyrite crystals precipitated. Presented study documents a unique glauconite occurrence and proposes that it can be successfully used for the detailed palaeoenvironmental reconstruction of the initial flooding of subaerially exposed terrains.

Bauxites are an excellent indicator of tropical palaeoclimate and subaerial exposure in the geologic record, where the study of their structures, textures, mineralogy, geochemistry, and cover deposits can provide invaluable insight into the palaeoclimatic and palaeoenvironmental conditions during their formation. The present study focuses on these aspects of the bauxite and its cover from the Rovinj-1 deposit with the aim of reconstructing the evolution of the palaeoclimate and palaeoenvironments during its formation. The Rovinj-1 deposit formed during the early Kimmeridgian to late Tithonian subaerial exposure phase on the Istrian part of the Adriatic Carbonate Platform (AdCP). The bauxite formation can be divided into two phases: (1) the formation of pelitomorphic bauxite under humid tropical climate, and (2) the erosion and redeposition of bauxite at the end of its formation due to climatic aridification. The climate aridification also led to increased iron oxide formation, which scavenged numerous trace elements, especially light and middle rare earth elements, causing their increase in the upper part of the deposit. The upper part also exhibits negative Ce anomalies, while the lower part displays high Ce anomalies. The bauxite formation was followed by an internal transgression during which a karstic lake formed above the bauxite. At the beggining of the transgression, the deposition of the alternation of limestones and clays started under anoxic to euxinic conditions, and equivocal to oxic conditions towards the end of the transgression, indicating the shift in lake conditions from restricted to open which is also supported by the presence of glauconite as this reflects the increasing marine influence. This sequence was interpreted as a blue hole sequence. The clays/marls of the cover sequence also reflect climatic aridification as they show a gradual increase in mixed-layer illite-smectite and illite content and a decrease in kaolinite content. The end of this regional subaerial exposure phase and the restoration of full-marine carbonate deposition is marked by the deposition of the limestones of Kirmenjak unit covering the bauxite deposit. Overall, this study enabled a detailed palaeoclimatic and palaeoenvironmental reconstruction of the Istrian part of the AdCP, expanding the current knowledge of the conditions at the AdCP during the Late Jurassic.

The geochemical signature of weathering and pedogenesis in a temperate humid climate on two parent material types in the foothills of Medvednica Mt. was studied. Five soil profiles on Miocene marls and three sections of Plio-Quaternary (PlQ) proluvial sediments with overlying soil and weathered material were analyzed. The (clay) mineralogy of all profiles and sections had been determined in previous studies. The chemical composition of the samples was determined by inductively coupled plasma emission spectroscopy (ICP-OES) and inductively coupled plasma mass spectroscopy (ICP-MS). Poorly ordered Fe and Mn oxides were determined in the PlQ sediment and overlying soil samples by atomic absorption spectroscopy (AAS), after oxalate dissolution in the dark. The concentrations and element ratios were used to determine element enrichment/mobility and intensity of chemical weathering, material provenance, and to compare the geochemical signatures with previously obtained clay mineralogy results. Trace elements in the Miocene marls, including rare earth elements (REE), indicate the continental origin of the marl siliciclastic component, while more scattered geochemical data of the PlQ sediments reflect their proluvial/torrential nature. The mass transfer coefficient (tau) for major elements and element ratios of the Miocene marl profiles indicate chemical weathering and pedogenesis of lower intensity. The geochemistry of these samples shows homogeneity within the profiles. In the geochemical signature of the PlQ sections, a chaotic proluvial deposition of the material is visible, as well as the heterogeneity with the overlying soil and weathered material. Overall, the geochemistry results largely support the clay mineralogy of the samples and demonstrate how a multiproxy approach can help test hypotheses about past environments and provide valuable additional information for complex paleoenvironmental studies.

Weathering indices are widely used in soil science and some other environmental disciplines for a variety of purposes (e. g. for soil classification, in soil formation studies, or in wider palaeoclimatic research). Two main categories of weathering indices have been developed: geochemical and mineralogical. In both cases, an approach is developed that takes into account the compositional nature of the geochemical data. To date, however, the most commonly used weathering indices are geochemical indices that do not consider the geochemical data as compositional. Although the compositional approach minimises possible statistical errors, the weathering indices developed in both approaches, i.e. the compositional and the classical, axiomatically assume two things that are inaccurate in some cases. First, that soil composition is invariant with respect to preferential translocation of clay sized particles, i.e. lessivage, and second, that the role of selective sorting of minerals during transport is neglected, which in extreme cases could mimic weathering. As a result, in some cases bulk analyses of mineralogical and geochemical content are an unreliable tool for determining soil weathering rates. To overcome these difficulties, this study proposes a new weathering index (Wp-min) based on the orthonormal log ratio (olr) transformation of quantitative mineral data derived from silt to sand sized allochthonous mineral assemblages. The size fraction used ensures that only the parent mineral assemblages, which are not prone to translocation, are analysed. In this paper, olr transformation is done using the concept of balances. This enabled the construction of variables, which essentially are various mineral log ratios, with the desired properties, i.e. transport invariance and sensitivity to selective dissolution. In this way, undesirable effects, i.e. selective sorting and lessivage, which ultimately affect bulk analyses, are avoided, allowing a more accurate estimation of weathering in the soil profiles studied. The new index was validated by comparison with the geochemical W index, which was modified by consulting the standardized variation matrix prior to element selection. Ultimately, compared to the geochemical index, the new index was better able to characterise weathering in soils where intense lessivage was detected. The study was conducted on terra rossa soils, which have common source, mostly of an aeolian origin.

This paper investigates occurrence of metal(loid)s, and size-dependent changes in their concentration in recent marine sediments from coastal and open-sea environments in the eastern Adriatic. Size fractionation of sediments was performed after removal of organic matter (OM), and the individual fractions, comprising particles below 8 μm, 4 μm, 2 μm, 1 μm and 0.45 μm, were analysed using HR ICP-MS. The concentrations of most elements increased with decreasing particle size, as a result of accumulation of clay minerals and Fe and Mn (oxyhydr)oxides. A decrease in concentrations was observed for Ba, Sr, Ti and U, due to lowering of the carbonate content and presence in the coarse-grained and heavy mineral fraction. The highest element concentrations were determined in the fraction comprising particles below 1 μm. Occasionally, depending on the sedimentological environment and/or the element in question, the peak concentrations occurred in the <2 μm or <0.45 μm fraction. The lowest size-dependent enrichment was observed for elements associated with aluminosilicates (Al, Be, Cs, Co, Fe, K, Li, Rb). A different size-dependent behaviour of the elements was observed between deep-sea areas and shallow environments under greater coastal influence, mainly due to differences in sediment sorting, and between the northern and central vs. southern Adriatic due to the different catchment geologies. The Fe and Mn (oxyhydr)oxides, abundant in the deep-sea sediments, played an important role in the geochemical cycle of As, Cd, Co, Mo, Sb and V.

Within the framework of the pan-European project “URban GEochemistry (URGE) in Europe – Soil, children, health”, pedological and geochemical investigations of the soils of the city of Sisak and its adjacent surroundings were carried out, and three urban and two rural soil profiles were examined. The mineralogical composition and concentration of selected potentially toxic elements (PTEs) Cr, Cu, Ni, Pb and Zn in the soil were determined. The Community Reference Bureau of Reference (BCR) sequential extraction procedure (SEP) of these PTEs was undertaken and the potential risk to human health and the environment was assessed. The concentrations of Cr and Ni are generally similar in urban and rural soil profiles, while the concentrations of Cu, Pb and Zn in soil horizons/layers are higher in urban profiles. The extracted fractions of PTEs gave the following general distribution: in urban soil profiles residual (RES) > reducible (ORG) or oxidisable (FEMN) > exchangeable (CARB), except for Cu where ORG > RES > FEMN > CARB, while in rural soil profiles RES > FEMN or ORG > CARB, except for Pb where FEMN > RES or ORG > CARB. The differences between soils in urban and rural profiles depend mainly on the historical land use, i.e. on the duration and intensity of anthropogenic influences on the soil and, to a lesser extent, on the geogenic origin of the parent material and the pedogenic processes. The studied elements in the urban soil profiles are predominantly of anthropogenic origin, indicating a possible influence of the ancient settlements of Segestica and Siscia and of heavy industry in the 20th century. The anthropogenic influences on the rural profiles are low and geogenic influences dominate. Risks to the environment were assessed in the soil profiles based on PTE concentrations in the CARB fraction and the sum of the CARB, ORG and FEMN fractions from BCR SEP. All calculated risks to human health and the environment were rated as no-risk, very low risk and low risk.

Terra rossa soils on the Istrian peninsula are generally considered polygenetic relict soils. They overlie and mark the youngest subaerial unconformity in the northwestern part of the Adriatic Carbonate Platform and are susceptible to erosional and redepositional processes. Terra rossa soils represent a valuable archive of information that can be used to understand present and past soil formation processes in the context of climate variability and landscape dynamics, especially in low-lying parts of the karst landscape where thicker deposits are typically found. We studied a 3 m thick terra rossa profile in a karst depression on the northernmost part of the southwestern Istrian planation surface and analysed the micromorphology, physical/chemical properties, geochemistry, bulk and clay mineralogy, and composition of heavy and light mineral fractions. The profile shows several signs of colluviation and polygenesis with clay distribution along the profile, clearly indicating lithic discontinuities. Kaolinisation, along with iron oxide formation, is the dominant process in the studied profile. Ferralitisation and lessivage processes were diagnosed throughout the profile, with intense clay translocation occurring despite the extremely stable soil microaggregates. In accordance with the WRB system, the profile is classified as Rhodic Lixisol (Clayic, Aric, Cutanic). This implies that some terra rossa soils, previously classified as e.g. Cambisols or Luvisols, might actually be Lixisols or other (sub-)tropical soils (e.g. Nitisols), in which relict properties are preserved in the present climate. The finding of a Lixisol in the study area indicates the old age of the surface of the karst depression and provides the first data on the burial history of the southwestern Istrian planation surface. We suggest the older Quaternary interglacials, the mid-Piacenzian Warm Period (Pliocene) and the Miocene Climatic Optimum as favourable periods for the formation of the studied soil.

Coherent provenance studies of soils that take into account data processing and the limitations arising from the physiochemical properties of the source material are scarce. In this study, the provenance of four terra rossa soils on the Istrian peninsula and four terra rossa soils on the island of Susak is investigated based on the heavy mineral assemblages of the soils and their potential sources. The heavy mineral data are treated as compositional data, which means that the information is stored in the ratio between the components and not in absolute values. The provenance of the allochthonous soil components showed that they originated from the now submerged alluvial plain i.e., emerged Adriatic shelf, mainly fed by alpine material during low sea levels. In the case of Savudrija loess and red paleosol and partly Koreniki sections, the allochthonous material originated from the local Eocene flysch, also windblown from the emerged shelf. The degree of mineral weathering, which correlates with the Fed/Fet and the total portion of heavy minerals, shows that this allochthonous component is a parent material of the terra rossa soils, not an impurity. Thus, the main role of the carbonate rocks with which the terra rossa soils are associated is to maintain a specific and favorable conditions for their formation. The origin of the parent material is associated with sea level oscillations, i.e., in times of low sea level the material was windblown from the emerged shelf, onto the land, this recurrent process can probably be traced back to the Oligocene. During periods of high sea level, i.e., warmer periods, terra rossa formed. Thus, the formation of terra rossa soils in the northern Adriatic is a recurrent process that may have begun at least since the Miocene. Consequently, abundance of terra rossa on the eastern Adriatic coast is due to a large emerged shelf area that supplied the carbonate platform with siliciclastic material during low sea levels.

Little is known about the bonfire impact on microbial properties in soil. This work aimed to study moderate- to high-severity experimental burning (250 °C) compared to unburned Cambisol in a natural Mediterranean environment (Croatia) on selected soil properties. The soil was sampled immediately and 1, 2, 4, and 6 months after the fire. The fire increased the mean weight diameter, water stable aggregates, and water repellence in different soil fractions, and the observed effect was the strongest immediately after the fire. It also altered soil pH, electrical conductivity, total nitrogen carbon, and sulphur content, and completely destroyed carbapenem-resistant bacteria, but did not significantly affect the soil’s mineralogical properties. Six months after the fire, most microbial properties (save for pH) returned to near control values. Heterotrophic, sporogenic, and phosphate-solubilising bacteria started to recover after a month, whereas the population of carbapenem-resistant bacteria was destroyed initially, but recovered by the fourth month after the fire. Dehydrogenase activity was not significantly affected, but proper recovery started four months after the fire. Even though Cambisol showed some resilience to fire and its properties mostly returned to normal by the sixth month, and a full recovery is expected to occur later, as vegetation returns.

Pipeline spills and pollution of the environment by crude oil pose a threat to natural resources, especially soil and water. One such incident occurred on 25 September 2018 in the area of Budrovac (Croatia; 46°00′14.6″ N 17°04′16.8″ E) on agricultural land as a pipeline spill. Bioremediation of the contaminated soil was carried out with organic pollutants using an environmentally safe absorbent Spill-Sorb (Canadian Sphagnum Peat Moss) and a mineral fertilizer—nitrogen. The experiment was conducted in the greenhouse of the Faculty of Agriculture, Croatia, during a six-month (October 2018–April 2019) study. Samples of agricultural soils contaminated with total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs) were taken after the rupture of the local gas condensate pipeline. The experiment was conducted in five treatments in triplicate: I-control (clean soil); II-100% contaminated soil + organic absorbent + nitrogen; III-100% contaminated soil + organic absorbent; IV-50% clean soil + 50% contaminated soil + organic absorbent + nitrogen; and V-50% clean soil + 50% contaminated soil + organic absorbent. The soil properties studied were pH, organic matter content, carbon and nitrogen content and ratio, and changes in the concentration of potential organic contaminants—TPHs and individual PAHs. The results demonstrated that the mixture of organic absorbent and nitrogen efficiently removed organic pollutants from the contaminated soil within six months. However, the application of Spill-Sorb alone was more effective for the degradation of hydrocarbons. The effectiveness of the absorbent studied was dependent on the concentration of organic pollutants and nitrogen application.

Soil water regime, as one of the key components of soil fertility, refers to the quantity, retention, and movement of soil water. Rather than through expensive and/or time-consuming measurements, it can be assessed from the field-observable morphological properties in the soil profile. Excessively wetted soils have a specific morphology, and are therefore often referred to as hydromorphic. Their morphology is caused by various soil redoximorphic features (RMFs), resulting from the reduction, translocation, and oxidation of iron and manganese oxides. Hydromorphic soils largely comprise Gleysols and Stagnosols (along with Gleyic Fluvisols) that are excessively wetted by groundwater, precipitation and/or flooded water. Their morphology is often described/analyzed with different terms/criteria in line with their global distribution. This complicates the comparison and classification of such soils and thus their use or reclamation. This review paper describes and compares common RMFs and explains their formation. It then proposes the revised Croatian terms for these features, which are in line with the terms used in the international soil classification systems of WRB and/or Soil Taxonomy. Furthermore, the criteria/rules used for diagnosing RMFs when classifying hydromorphic soils are critically reviewed. Finally, it is shown that a methodologically sound RMFs description can provide a quick insight into the crucial soil water regime parameters, such as location and duration of soil saturation, the origin of the excess soil water, recentness of excessive soil wetting, etc. However, depending on the research objectives and/or actual soil conditions, field soil description cannot always fully replace continuous field monitoring of the soil water regime and/or laboratory and micromorphological soil analyses.

This study investigates the mineral composition, particle size distribution and geochemical characteristics of Calcocambisol, colluvium and recent marine lake sediment in a narrow intertidal seashore zone of the Veliko Jezero on the Island of Mljet (Croatia). The obtained results show that the fractions of Calcocambisol/colluvium less than 2 mm and 2 µm display similar particle size distribution (PSD) curves compared to marine lake sediments containing larger particles in these fractions. The smallest fractions of the investigated materials that are less than 1 µm show identical PSD curves. The bulk and clay mineral composition of the marine lake sediment show that the non-carbonate fraction is derived from weathering of the surrounding soils and colluvium containing quartz, feldspars and phyllosilicates (illitic material, kaolinites, chlorite, and a mixed-layer clay mineral, MLCM), as well as the authigenic formation of early-diagenetic pyrite, while one part is related to the yield of material by aeolian deposition (amphibole). The observed difference between the phyllosilicate mineral phases in the clay fraction of the Calcocambisol/colluvium and the carbonate-free clay fraction of the marine lake sediment is related to 1) the presence of chlorite in the marine lake sediment and 2) the higher content of MLCM in the Calcocambisol/colluvium. The chlorite in the marine lake sediment was inherited from the Calcocambisol/colluvium as a result of soil erosion prior to its complete destabilization in the soil. High Chemical Index of Alteration (CIA) values in the Calcocambisol and colluvium clearly indicate their intense weathering. Based on the Sm/Nd and Ti/Al ratios, it can be concluded that the aluminosilicates in the Calcocambisol, colluvium and marine lake sediment are of the same provenance. The distribution of each analysed element among the sequential fractions is very similar in both the Calcocambisol and colluvium. The highest concentrations for most of trace elements in the Calcocambisol, colluvium and marine lake sediment was determined in their residual fraction. Mn, Co and Pb show a different partitioning between the Calcocambisol/colluvium and marine lake sediment, respectively.