Distribution Of Major Elements Research Articles

Petrography and geochemistry of the Late Devonian Pirispiki Formation in northern Iraq: Implications for Reservoir Characteristics and reconstruction of depositional environments

Petrographic, mineralogical and whole-rock geochemical investigation of siliciclastic and interbedded carbonate rocks from the Devonian Pirispiki Formation in the Nazdur and Ora sections, extreme northern Iraq, were conducted to assess reservoir potential and to study the effects of Devonian deformation (Middle Paleozoic, Caledonian event) on paleogeography and sediment transport in northern Gondwana. Traditional petrographic and scanning electron microscopy, X-ray diffraction and X-ray fluorescence were used. The main results are: sandstones from the Ora section contain significantly more quartz and less lithic fragments than those from the Nazdur section. This variation in sandstones composition may reflect uplifting effect due to Middle Paleozoic event and/or different provenance. The most notable feature of the major and trace elements distribution in the studied mudstones and sandstones is that they are significantly enriched in U but significantly depleted in Zr and Hf. The relative absence of zircon in the samples could account for the depletion of Zr and Hf, two elements linked to zircon. The extremely high U concentrations seen in mudstones and sandstones may relates to precipitation by circulating groundwater where it transported into the sediment prior to cementation. No fauna or flora have previously been reported from the Pirispiki Formation at outcrop in Iraq. The widespread occurrence of shell fragments in sandstones from the Nazdur section combined with the presence of eight dolomite and dolomitic marl beds suggest that the lower and middle parts of this section were deposited in a marine environment. This has not previously been recognized. Previous correlations between the Chalki basalts in the Chia Zinnar anticline and conglomerates in the Ora anticline are not supported by our data. We propose a new correlation between the sections in northern Iraq and those from southern Turkey and western Iraq that suggests that the Pirispiki Formation was deposited during a relative sea-level fall. The paleo-shoreline advanced northward through the study area during the Late Devonian. The Pirispiki Formation has been proposed as a potential reservoir for hydrocarbons sourced in underlying Paleozoic units. However, the sandstones and carbonates investigated during this study have no potential as a reservoir due to pervasive carbonate cements.

Scallop shells as biosorbents for water remediation from heavy metals: Contributions and mechanism of shell components in the adsorption of cadmium from aqueous matrix

To ascertain their potential for heavy metal pollution remedy, we studied the adsorption mechanism of cadmium onto scallop shells and the interactions between the heavy metal and the shell matrix. Intact shells were used to investigate the uptake and diffusion of the metal contaminant onto the shell carbonatic layers, as well as to evaluate the distribution of major and trace elements in the matrix. LA-ICPMS measurements demonstrate that Cd is adsorbed on a very thin layer on the inner and outer surfaces of the shell. Structural and thermal analyses showed the presence of 9 wt.-% of a CdCO3 phase indicating that the adsorption is mainly a superficial process which involves different processes, including ion exchange of Ca by Cd. In addition, organic components of the shell could contribute to adsorption as highlighted by different metal uptake observed for shells with different colours. In particular, darker shells appeared to adsorb more contaminant than the white ones. The contribution of the organic shell components on the adsorption of heavy metals was also highlighted by the element bulk content which showed higher concentrations of different metals in the darker specimen. Raman spectroscopy allowed to identify the pigments as carotenoids, confirmed by XRD measurements which highlighted the presence of astaxanthin phases. The results presented here provide new insights into the Cd adsorption mechanism highlighting the important contribution given by the organic components present in the biogenic carbonate matrix. Furthermore, the high efficiency of Cd removal from water by scallop shells, supported by adsorption kinetic and isotherm studies, has been demonstrated.

Mineralogical and geochemical characteristics of the Nkoteng-Mbandjock alluvial clays from Sanaga valley deposits (Cameroon, Central Africa): Implications for source weathering and provenance

This research investigates the physico-chemical, mineralogical and geochemical attributes of alluvial clayey sediments in the Nkoteng-Mbandjock regions of the Sanaga valley, Cameroon. The primary objective is to elucidate the source area-weathering and provenance of these sediments. Grain size distribution analyses were conducted using the Robinson-Kӧln's pipetting method. The physico-chemical parameters were evaluated by an HACH-HQ11d brand electric pH meter, while the mineralogical compositions were determined by X-ray Diffraction. Major and trace element concentrations were measured employing X-ray Fluorescence and Inductively Coupled Plasmas-Mass Spectrometry. Textural classification identified the Sanaga valley alluvial clay deposits as predominantly silty clayey and clayey muddy. Geochemical classification diagram positioned them in the shale and Fe-shale fields. Weathering indices of alteration exhibited a consistent trend indicating a high degree of weathering in the source rock. A low Na2O/K2O ratio (average 0.18) and a high Index of Compositional Variability (ICV; average 2.29) suggested immature sediments. Additionally, low SiO2/Al2O3 ratio (average 3.93) implied an origin from stable settings with recycled inputs. These characteristics were further supported by elemental ratios such as Zr/Sc (average 47.12), U/Th (average 0.24) and Th/Sc (average 1.48). Furthermore, indicators like V/Cr (average 1.17), U/Th (average 0.24) and authigenic U (average −1.67) values suggested the deposition of the Sanaga valley alluvial clay under oxic conditions. The collective analysis of major and trace element distribution revealed felsic sources with minimal contributions from mafic rocks. These findings contribute to a comprehensive understanding of the geological processes and conditions influencing the composition and characteristics of the studied alluvial clay deposits in the Sanaga valley.

Non-negligible contribution from coastal erosion to sedimentation around the archipelago: A case study of Miaodao Archipelago

The Miaodao Archipelago, located in the southern Bohai Strait, serves as a major route for the exchange of energy and materials between the Yellow and Bohai seas and is distinguished by a complicated hydrodynamic environment and provenance. Based on the grain size and elemental data of 107 surface sediment samples from the archipelago waters, and 58 coastal erosional sediment and bedrock samples, this study investigated the factors influencing the geochemical elemental distribution, discusses the provenance of the surface sediments and relative contributions, as well as proposes a sediment source–sink model for the region. The distribution of major and trace elements in the surface sediments, typically characterized by “high in the north, low in the south” patterning (except for SiO2, Ba, and Sr), with their contents primarily controlled by the input of terrestrial materials. The surface sediments in the study area are separated into the geochemical subdivisions of north and south. The main provenances of the study area include the Yellow River, the nearshore Miaodao Archipelago, and the north side of nearshore Penglai, whose sediments were transported under the combined action of the Shandong Peninsula's tidal current, waves, and longshore current. Deposition occurred under the capturing action of the archipelago. The relative contributions of the three provenance areas were 74.7%, 15.5%, and 9.8%, respectively; the relative contribution of coastal erosion reaches 1/3 of the river. Studies have demonstrated that the contribution of coastal erosion provenances to sea surface sediments is non-negligible, and in fact, it may even be quite important; thus, in the context of decreasing riverine inputs to the sea and enhanced coastal erosion processes, the contribution of coastal erosion requires special attention.

The Early Cenozoic Volcanism of the Northern Okhotsk Region System of Grabens and Faults

Abstract —We studied geochemical compositions of the early Paleocene basaltic and andesite dikes associated to linear zones of the Lankovo–Omolon shearing system (Northern Okhotsk region) and basalts of the Evdyreveem volcanic field associated to the Okhotsk–Penzhinsk fault system, and compared them to other synchronous manifestations of basic volcanism: andesibasalts and andesites of the studied earlier Garmanda field, as well as with the Late Cretaceous basalts of the Mygdykit Formation of the Northern Okhotsk region, roofing the Okhotsk–Chukotka volcanic belt. The isotopic composition of Sr and Nd in dikes, the distribution of major and trace elements with the ratios of noncoherent elements indicate the formation of volcanic bodies in the environment of continental margin rifting, which is confirmed by the combination of depleted, intraplate and above subduction geochemical features of their composition. Such behavior of the elements indicates multi-stage processes of the earlier Mesozoic supra-subduction fluid metasomatosis. Melting of an ancient buried Cretaceous slab may explain the appearance of such “above subduction” marks as the Nb–Ta negative anomalies in the studied basaltoids. Andesite dikes are characterized by higher isotope ratios of Nd and lower Sr, with lower absolute concentrations of trace elements and more pronounced anomalies on spider plots.

Landscape regulation of microbial use of terrestrial carbon in boreal streams

Microbes decomposing leaf litter in aquatic ecosystems are exposed to two major sources of carbon (C), namely, particulate organic C (POC) and dissolved organic C (DOC). The use of DOC relative to POC during litter decomposition likely depends on the availability of DOC, which in turn is regulated by the characteristics of the surrounding landscape, although this extrinsic indirect control of DOC use remains largely unexplored. We have investigated how variations in stream physical and chemical characteristics, distribution of major landscape elements (i.e., forest, mires, and lakes), and riparian vegetation community composition (i.e., relative cover of deciduous vs. coniferous tree species) influence DOC use by leaf-associated microbes (LAM). Specifically, in a boreal stream network of ten first- to third-order streams, we related in-stream characteristics, landscape elements, and riparian vegetation community composition to DOC/POC respiration ratios (i.e., the amount of CO2 produced by LAM respiration of DOC + POC divided by the amount of leaf C mass lost through decomposition). The results showed that DOC/POC respiration ratios were > 1 in most of the study sites, indicating that LAM use a substantial amount of DOC during leaf litter decomposition. This microbial reliance on DOC varied with in-stream DOC and nutrient concentrations, proportional mire and forest cover, and riparian vegetation community composition. In particular, high mire and coniferous cover increased DOC use by LAM. As such, landscape configuration and how it is modified by land use and climate change must be considered in order to understand microbial turnover of terrestrial C in boreal streams.

Sedimentary records of environmental evolution in Dongzhai Port mangrove swamps (South China) over the last hundred years: Insights from corrections of grain-size effects

Mangrove sediments play a vital role in the biogeochemical processes of elements by behaving as both sources and/or sink for nutrients and trace metals. Under the combined impacts of grain-size effects and human activities, it is difficult to accurately assess the sources and degree of pollutants. For this purpose, two cores were collected from a mangrove swamps of Dongzhai Port (South China) and analyzed for temporal distributions of grain size, nutrients, major and trace elements, and 210Pb activities. Due to the significant vertical variation of grain size with depth, linear regression analysis was conducted based on trace metals (i.e., Pb, Cr, Ni, Cu, Cd, Zn) and normalized element Al to reconstruct local environmental background. The results showed that the contents of Cu, Cd, and Zn in the surface layers exhibited significantly increasing trends since the 1980s, with maximum contents of 9.06, 0.16, and 228.66 μg g−1, and their enrichment factors up to 1.52, 1.40, and 1.50, respectively. It should be attributed to shrimp farming and domestic sewage, indicating slight anthropogenic inputs. The evolution process was divided into three stages in Dongzhai Port over the last 100 years: before 1980 AD, 1980-2000 AD, and from 2000 AD to the present, corresponding to the stages of natural deposition, domestic pollution, and aquaculture pollution, respectively.

Rare earth elements into the aqueous phase of mud volcanoes of the Kerch-Taman region

This article presents original data on the content and distribution of major and rare earth elements into the waters phases from 26 mud volcanoes within the Kerch-Taman region. According to the chemical composition of the studied mud volcanic waters are represented by Na-Cl and Na-HCO3-Cl types, and the Cl/Br, Na/Cl, and Y/Ho ratios specify three main genetic groups of volcanoes. It was found that the rare-earth element contents in the aqueous phase of mud volcanoes are low (fractions of μg/L) and are distinguished by negative cerium anomalies and positive europium and holmium anomalies. The highest REE concentrations are observed in mud volcanoes located within the oldest Cretaceous sediments in the area of fault influence. As the distance from the Mesozoic source ΣREE sharply decreases. It has found that the free CO2 content in the aqueous phase regulates the REE content in waters and the value of cerium and europium anomalies.

Spatial distribution of major and trace elements in artificial lakes in Serbia: health risk indices and suitability of water for drinking and irrigation purposes

Lakes and reservoirs are the main water resources for household, irrigation, and industrial use. Hence, it is necessary to control water pollution and have reliable information on water quality, which refers to its suitability for a particular purpose. The main objective of this study was to evaluate the suitability of water for drinking and irrigation purposes from ten artificial lakes on the territory of the Republic of Serbia. The physicochemical parameters were determined using standard analytical methods, whereas the optical emission spectrometry with inductively coupled plasma, ICP-OES, was used to determine the concentrations of 23 macro-, micro-, and trace elements in water. Health risk indices of drinking water and its suitability for irrigation purposes were evaluated. The results of physicochemical parameters, except for total organic matter, indicated that most samples were within the recommended values. Among analyzed elements, the concentration of Mg was elevated in the water of the lakes Srebrno and Prvonek. The results of health risk assessment clearly showed that there was no acute health risk (HQA < 1), whereas long-term risk (HQL) in the studied lakes was observed with respect to As (lakes Grlište and Srebrno), Mn (lakes Srebrno and Prvonek), Ni (Lake Vrutci), and Sr (Lake Grlište). The irrigation criteria indicated that the water from the examined lakes had satisfactory quality for this purpose, except for residual sodium carbonates (RSC). This criterion indicated low quality or unsuitability of the water in 7 lakes. The main outcomes provided valuable information on the suitability of water from the artificial lakes for intended uses.

Contributions of the Yangtze River and Yellow River to terrestrial organic carbon deposition in the Yangtze River Estuary during the last 700 years

Terrestrial organic carbon (OC) could be transported to marginal oceans by large rivers and deposited under different hydrological conditions. A mixture of the fresh & lithospheric OC, superimposed by the OC from different rivers, makes it challenging to distinguish sources and contributions of terrestrial OC. Here, we employed multiple geochemical proxies, including the hydrogen isotopic composition of leaf wax (δDwax), the carbon isotopic composition of total organic carbon (δ13Corg), TOC/TN ratio, and major element distributions, to investigate the variability in sources of terrestrial OC in the Yangtze River Estuary (YRE) since 1270 CE. Our results revealed that the terrestrial OC deposition in the YRE was lower before 1950 CE and considerably increased after 1950 CE. The δDwax record in core A3 indicates that the OC deposition in the YRE was primarily modulated by the variability of El Niño-Southern Oscillation (ENSO) and East Asia Summer Monsoon. The strengthened El Niño-like state since 1600 CE resulted in increased precipitation in the middle and lower reaches of the Yangtze River basin and in turn, affected the terrestrial OC deposition in the YRE. Several episodes with lower carbon preference index (CPI) values of n-alkanes (CPI < 3) were identified. These episodes were concurrent with the streamflow shift of the ancient Yellow River during the transitions from wet to dry conditions, highlighting the potential contribution of the ancient Yellow River to the aged OC deposition in the YRE.

Comparison on distribution and sources of typical major and toxic trace elements in various glacial watersheds of the northeast Tibetan Plateau

Toxic and major elements, such as As and Fe, in watersheds can significantly impact the surrounding water environment and ecosystem. Thus, in this study, we conducted an investigation into the origins and spatial distribution of typical toxic trace elements (As and Mn) and crustal major elements (Al, Fe, and Ti) in suspended particulate matter (SPM) across various glacial watersheds located at different elevations in the northeastern Tibetan Plateau (NETP) from June to July in 2017. The results revealed that the mean value of each element followed the order of abundance in the samples, with Al having the highest mean value at 21307 µg/L, followed by Fe at 13366 µg/L, Ti at 1520 µg/L, Mn at 245 µg/L, and As at 66.6 µg/L. Moreover, our study identified high content of these elements from the Dabanshan Snowpack, Laohugou Glacier No.12, and Yuzhufeng Glacier in the upper reaches of the basin, which were found to be 9.9, 10.2, and 19.4 times higher, respectively, than that of the upper reaches of the Heihe River. We found that As and Mn exhibited clear indications of anthropogenic influence on a local and regional scale. The calculated enrichment factor (EF) demonstrated a significant As enrichment (EF>100) in the Qiyi and Lenglongling Glaciers, possibly resulting in the release of upstream glacier melt and anthropogenic-derived As deposition. Our findings suggested that the upstream region was primarily linked to glacier meltwater discharge. In contrast, the middle and lower reaches of the basin exhibited a more pronounced influence from local human activities. Based on the findings, the water environment of the glacier watershed appears to be in good condition overall. However, the presence of elevated levels of As element in the water system can be traced back to both anthropogenic and natural factors. As a result, ensuring the safety of the water supply for nearby residents is a matter of utmost concern. This study provides a comprehensive examination of hydrochemical variations and the overall water environment of high-altitude glacier basins in the NETP, offering valuable insights into the topic.

Robust dating of Pb–Zn skarn systems by LA–ICP–MS garnet U–Pb geochronology

Lawu and Yaguila are two Pb–Zn skarn deposits in the eastern Nyainqêntanglha metallogenic belt, central Lhasa subterrane, Tibet. The genesis of Pb–Zn deposits in this belt and the crustal processes leading to their formation remain ill-constrained, mostly because of the lack of precise mineralization ages. We integrate textural information, geochemistry, and in-situ garnet U–Pb geochronology to constrain the timing and genesis of Pb–Zn mineralization. Garnets from the two deposits display oscillatory compositional zoning (And14Gr86 to And100) and contain variable U contents (0.07–5.3 ppm). Aluminum-rich garnet displays a chondrite-normalized rare earth element (REE) fractionation pattern in which LREEs are depleted relative to flattish HREE segments. In contrast, Fe-rich garnet shows LREE-enriched, relatively HREE-poor patterns with positive Eu-anomalies. Uranium concentration is correlated with total REE and Fe components in garnets, implying that U incorporation is largely controlled by coupled substitution mechanisms. The same garnets also contain measurable contents of other metals (up to hundreds of ppm), such as Sn, W, and In. The distribution and fractionation of major and trace elements in zoned garnets record periodic fluid pluses with different compositions during hydraulic fracturing. The new garnet U–Pb data show that the Yaguila deposit formed between 68.5 ± 3.4 and 65.0 ± 4.7 Ma, and the Lawu deposit formed at 54.6 ± 2.9 Ma. Within the geochronological framework of igneous rocks and Pb–Zn mineralization in the Nyainqêntanglha metallogenic belt, the new garnet ages suggest a magmatic-hydrothermal origin for related mineralization, with the causative magma likely derived from partial melting of ancient continental material due to rollback and subsequent breakoff of the Neo-Tethys oceanic slab during India–Asia continental collision. This study highlights the opportunities offered by garnet U–Pb dating for elucidating the formation age and ore genesis of base metal skarn systems.

Distribution of Minor and Major Metallic Elements in Residential Indoor Dust: A Case Study in Latvia.

The coronavirus disease 2019 (COVID-19) pandemic has not only brought considerable and permanent changes to economies and healthcare systems, but it has also greatly changed the habits of almost the entire society. During the lockdowns, people were forced to stay in their dwellings, which served as a catalyst for the initiation of a survey on the estimation of the metallic element content in residential indoor dust in different parts of Latvia. This article presents the study results obtained through the analysis of collected dust samples from 46 dwellings, both in the capital of Latvia, Riga, and in smaller cities. Two methods were employed for indoor dust collection: vacuum sampling and manual sampling with a brush and plastic spatula. After microwave-assisted acid extraction, the samples were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) in terms of the major (Na, K, Ca, Mg, Al and Fe) and minor (Mn, Ni, Co, Pb, Cr, As, Ba, Li, Be, B, V, Cu, Zn, Se, Rb, Sr, Cd, La, Ce and Bi) elements. For the data analysis, principal component analysis was performed. Among the measured metals, the highest values were determined for the macro and most abundant elements (Na > K > Ca > Fe > Mg > Al). The concentration ranges of the persistently detected elements were as follows: Pb, 0.27-1200 mg kg-1; Cd, 0.01-6.37 mg kg-1; Ni, 0.07-513 mg kg-1; As, 0.01-69.2 mg kg-1; Cu, 5.71-1900 mg kg-1; Zn, 53.6-21,100 mg kg-1; and Cr, 4.93-412 mg kg-1. The critical limit values of metallic elements in soil defined by the legislation of the Republic of Latvia (indicating the level at or above which the functional characteristics of soil are disrupted, or pollution poses a direct threat to human health or the environment) were exceeded in the following numbers of dwellings: Pb = 4, Ni = 2, As = 1, Cu = 16, Cr = 1 and Zn = 28.

Geochemistry and assessment of groundwater resource in coastal arid region aquifer (Dahab delta, South Sinai, Egypt)

Dahab is a tourist city located in the Sinai Peninsula, downstream of the Dahab watershed, as a part of the arid coastal region. Groundwater samples have been collected from the Dahab delta and were tested for salinity, major ions, minor elements, and heavy metals to investigate the geochemical processes deteriorating the groundwater quality. The spatial distribution of major, minor, and trace elements integrated with the geochemical interrelationships using the cumulative salinity bases mixing curves have been utilized to investigate the main source(s) of groundwater recharge and salinization origin in Dahab delta aquifer. The groundwater salinity ranges from 339 upstream of Dahab watershed to 53,216 mg/L downstream in the delta area. The groundwater varies from fresh, brackish, and saline water. The spatial distributions of major ions, minor elements (Si, and Br), and heavy metals (B and Sr) confirm that the recharge comes from the upstream watershed. According to the mixing model curves, groundwater quality has declined due to interactions with the aquifer matrix, mixing with seawater, and rejected brine from the reverse osmosis desalination plants. The fresh/brackish groundwater classes have been recorded in the northwestern part of the study area close to the basement rocks, where the Quaternary aquifer receives considerable recharge through the underneath fractures, joints, and faults that enhance the subsurface recharge. The samples with a high saline groundwater class have been recorded in the eastern and southern parts of the delta, demonstrating the effects of seawater intrusion. Based on WHO guideline criteria, the assessment of groundwater for various uses has determined that most groundwater samples from the alluvial aquifer (91%) are unfit for human consumption. The Water Quality Index indicates that the groundwater in the southern part of the delta is not suitable for all uses due to mixing with the seawater, and injection of rejected brine water from the desalination plants. In the north, groundwater is unfit for drinking and aquatics, excellent for recreation, marginal for irrigation, and fair for livestock. The groundwater in coastal arid region aquifers has deteriorated due to seawater intrusion.

Paleoproterozoic East Pana Layered Intrusion (Kola Peninsula, Russia): Geological Structure, Petrography, Geochemistry and Cu-Ni-PGE Mineralization

The East Pana intrusion is a part of the Paleoproterozoic Fedorova–Pana complex (FPC), which belongs to the group of Fennoscandian layered mafic–ultramafic massifs. This article discusses the magmatic stratification of the East Pana intrusion, as well as Cu-Ni and platinum-group elements (PGE) mineralization (PGE zones A, B and C) in its various parts with a total length of more than 20 km, including the East Chuarvy PGE deposit. Based on the whole-rock data on the distribution of major, trace, and ore-forming elements, it is assumed that PGE zone A belongs to the main ore–magmatic system of the FPC, while PGE zones B and C belong to the minor ore–magmatic systems. At the same time, additional magmatic injection played an important role in the formation of economic Cu-Ni-PGE mineralization (PGE zone B), characterized by high PGE concentrations and moderate palladium enrichment. On the normalized distribution spectra of trace elements, the crystallization products of this injection (Gabbronorite Zone 2) have a positive Zr-Hf anomaly, which distinguishes it from host rocks with an anomaly of the opposite sign (Gabbronorite Zone 1, Gabbro Zone). It is assumed that this portion of magma was intruded as a sill of crystal mush, the fractionation of which at depth led to its enrichment with residual liquid.

A New Mapping Protocol for Laser Ablation (withFast‐Funnel) Coupled to aTime‐of‐FlightMass Spectrometer (LA‐FF‐ICP‐ToF‐MS) for the Rapid, Simultaneous Quantification of Multiple Minerals

Althoughin situanalysis by LA‐ICP‐MS is considered a rapid technique with minimal sample preparation and data reduction, mapping areas of millimetres in size using a small beam (&lt; 15 μm) can be time consuming (several hours) when a quadrupole ICP‐MS is used. In addition, fully quantitative imaging using internal standardisation by LA‐ICP‐MS is challenging in samples with more than one mineral phase present due to varying ablation rates. A new protocol for the quantification of multiple coexisting phases, mapped at a rate of about 12 mm2h‐1and a resolution of 12 μm × 12 μm per pixel, is presented. The protocol allows mapping of most atomic masses, ranging from23Na to238U, using a time‐of‐flight mass spectrometer (ICP‐ToF‐MS, TOFWERK) connected to a 193 nm excimer laser. A fast‐funnel device was successfully used to increase the aerosol transport speed, reducing the time usually required for mapping by a factor of about ten compared with a quadrupole ICP‐MS. The lower limits of detection for mid and heavy masses are in the range 0.1–10 μg g‐1, allowing determination of trace to ultra‐trace elements. The presented protocol is intended to be a routine analytical tool that can provide greater access to the spatial distribution of major and trace elements in geological materials.

Major elements concentration in soils. A case study from Campania Region (Italy)

In this study, 500 bottom soils and 7300 topsoils samples were collected to determine the major elements concentrations and to evaluate the correspondence of soil chemical contents and the local geology and to better identify background values. The <2 mm fraction of each sample was analysed for a total of 52 elements combining ICP-MS and ICP-ES techniques. This study focuses on the concentration and distribution of major elements: Al, Ca, Fe, K, Mg, Mn, Na, P and Ti. A combined methodological approach, which involved compositional data analysis, multifractal data interpolation, as well as enrichment factor analysis, was applied to the geochemical dataset. Results indicate that the compositional approach in the multivariate data analysis allows to better interpret the behaviour of elements in natural environment and in geochemical processes as compared to raw data and to improve the quality of related maps. The study has shown that the soils of the Campania region generally contain higher concentrations of investigated major elements than those assessed for European and Italian agricultural soils. In Campania, both bottom soils and topsoils contain higher concentrations of Al, K, Na, P and Ti in volcanic areas. Limestone and dolostone are responsible for higher Ca and Mg contents, while soils formed on siliciclastic deposits generally contain higher levels of Fe and Mn. P and Na concentrations are higher in volcanic soils, but the contribution of fertilizers, which is evident in some areas, should not be underestimated. Weathering processes play an essential role in the distribution of elements in soils, and this appears very evident mostly in volcanic areas. The observations are consistent with the results of the enrichment factors analysis.

Multi-element imaging of urinary stones by LA-ICP-MS with a homogeneous co-precipitation CaC2O4-matrix calibration standard.

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) studies on trace element concentration and their spatial distribution in CaC2O4-matrix urinary stones are important but powerfully rely on matrix-matched external calibration. In this work, CaC2O4 precipitate CaOx-1 which was doped with Mg, Cr, Mn, Fe, Co, Cu, Zn, and Sr was prepared by the homogeneous co-precipitation method. It had a homogeneous distribution of major (RSD of 0.46%) and trace elements (RSD of 1.83-6.92%) due to thenegligible concentration difference compared with that prepared by the heterogeneous co-precipitation method. Based on this, an analytical method for quantitative determination of elemental concentration in CaC2O4-matrix samples was established using CaOx-1 as a calibration standard, and the accuracy of this method was assessed by calibrating theelemental concentration in another synthetic CaC2O4 precipitate CaOx-2 with relative deviation (Dr) from - 11.43% (Mn) to 9.76% (Mg). Finally, a methodology for quantitative imaging of Mg, Cr, Mn, Fe, Co, Cu, Zn, and Sr in urinary stones via LA-ICP-MS was developed. From the elemental distributional maps, an annular texture can be found for Mg, Cu, Zn, and Sr, which corresponds to the annular white and brown texture in the real urinary stone. A homogeneous distribution of Fe and low concentrations of Cr and Co were found throughout the stone, while Mn was highly concentrated in the margin of the stone. All these results demonstrate that quantitative distribution patterns of Mg, Cr, Mn, Fe, Co, Cu, Zn, and Sr can be obtained by LA-ICP-MS using CaOx-1 as a calibration standard, which can provide potential evidence for urological and other medical studies.

Fluorine speciation and origin of Early-Middle Triassic bentonite deposits in Sichuan Basin, South China

Fluorine (F) is one of the most important environmentally harmful elements released by volcanic activity, and the bentonite deposits that formed from volcanic ashes are potentially harmful to the environment. However, the mechanisms governing F-rich bentonite formation and its F speciation composition remain enigmatic. The F-rich bentonite deposits are widely distributed in the Early-Middle Strata of the Sichuan Basin, South China. Detailed mineralogical and geochemical studies were conducted on the bentonite deposits from five sections of the Sichuan Basin. X-ray diffraction (XRD) analyses indicate that the F-rich bentonites mainly contain quartz, carbonates (calcite and dolomite) or gypsum, and clay minerals, while the clay minerals are dominated by illite and illite/smectite (I/S). Clay mineralogical studies suggest that bentonites were transformed from volcanic ashes during diagenesis by smectite illitization. The major and trace element distribution in F-rich bentonite deposits altered from volcanic ashes is most likely derived from felsic magmas, and alteration of the parent rocks (e.g., rhyolites) to bentonite is associated with leaching and subsequent removal of F. The total fluorine content (FTOT) of the bentonite samples ranged from 1,162 mg/kg to 2,604 mg/kg (average = 1773 mg/kg), well above the average FTOT contents of soils in the world. The results of the sequential extraction experiments show that the highest content is residual-fluorine (Fres), followed by carbonate-fluorine (Fcar) with a mean value of 1,556 mg/kg and 186 mg/kg, indicating carbonate is an important F sink in bentonite deposits. The average fluorine value of organic fluorine (For), Fe/Mn oxide-fluorine (Ffm) and exchangeable fluorine (Fex) are relatively low with an average value of 17.5 mg/kg, 6.8 mg/kg and 4.1 mg/kg, respectively. However, water-soluble fluorine (Fws) has a mean value of 4.0 mg/kg, which is higher than the corresponding average value in soils in an area susceptible to endemic fluorosis in China. Based on the characteristic of fluorine speciation, the fluorine in bentonite deposits may pose a risk to the environment. This study makes an important contribution to a better understanding of the characteristic of fluorine speciation in bentonites and the formation mechanism that governs fluorine enrichment in bentonites.

Geochemical-mineralogical analysis of ferromanganese oxide precipitated on porifera in the Magellan seamount, western Pacific

This study investigated ferromanganese oxide (Fe-Mn oxide) precipitated on porifera located on the tabletop of the Magellan seamount (OSM17, 1571 m depth) in the western Pacific. As the growth rate of Fe-Mn oxide is several mm/Myr and porifera skeletons are difficult to preserve posthumously, geochemical and mineralogical studies have not yet been conducted on this topic. Fe-Mn oxides from porifera have a morphological differentiation from general ferromanganese deposits because porifera act as substrates for the Fe-Mn oxide. The thickness of Fe-Mn oxide cannot be visually confirmed because it thinly precipitates on the skeletons of porifera. Therefore, high-resolution fluctuations are reflected in marine environmental factors, such as redox conditions and surface productivity over tens of thousands of years, compared to ferromanganese deposits representing tens of millions of years. Hence, the geochemical and mineralogical characteristics were investigated. Porifera skeletons were confirmed, displaying a stratified lattice-like structure, thickness of Fe-Mn oxide of up to 110 μm, and age of approximately 55,000 years. Irregular distribution of major elements of Fe-Mn oxide, Mn, Fe, Ni, and Co was due to the characteristics of the structures. The presence of Fe-vernadite, identified by quantitative and mineralogical analysis, indicates oxidative environmental conditions at the tabletop of OSM17. Biomineralization was identified by confirming the presence of Fe-Mn oxides with a globular, sheath-like structure. Because of its conservation state, species identification of porifera was not based on the shape of the spicule, but was confirmed to be Farrea occa. This study verified that the tabletop of OSM17 has been in an oxidative environment for approximately 55,000 years, and through species identification, high dissolved silica (DSi) concentrations provide appropriate conditions for Farrea occa to survive. The sample in this study can be used as a new indicator in paleo-environment research.