Trace element Geochemistry

The chemical weathering of rocks and minerals on the Earth’s surface leads to the mobilization and redistribution of elements and has (a) significant control on the chemistry of the soil-hydrosphere-atmosphere system, (b) a profound effect on the bioavailability and toxic effects of elements, and (c) applications in mineral exploration among others. In this study, we describe the sequential weathering of spessartine- and pyrope-bearing almandine garnet in metamorphosed banded magnetite quartzite from the Khetri Copper Belt, western India. Based on detailed microtextural relations the following sequence of garnet weathering is proposed: garnet → alumo-goethite1 → alumo-goethite2 → kaolinite ± (monazite + xenotime ± thorite) → haematite. Our study thus reports for the first time the presence of alumo-goethite, kaolinite, monazite, xenotime, and thorite in weathering assemblage of garnet. The sequential chemical weathering of garnet was both grain boundary-controlled and fracture-controlled. Tectonic fractures (developed during exhumation), reaction-induced fractures (developed due to volume expansion), and secondary porosity (developed due to volume reduction) collectively controlled the propagation of weathering. Integrating multiple lines of evidence, e.g., corrugated contact between the weathering phases, presence of pores, relative molar volume changes, and high mobility of most elements it is argued that the weathering progressed through an interface-coupled dissolution-precipitation process. In situ major and trace element measurements and mass balance calculations show that several major (Fe, Na, K, P) and trace elements (Cl, F, alkalis, alkaline earth elements, and first series transition and base metals) were added while Si, Al, Ca, Mg and Mn were lost during the garnet to alumo-goethite transformation. During kaolinitization, all the major elements except Si and Al were lost to the weathering fluid. The alkali and alkaline earth, first series transition elements, base metals excepting Cr were lost during this weathering stage. Phosphorous, REEs, and Th were locally immobilized as monazite, xenotime, and thorite. In the more advanced stages of weathering, kaolinite was replaced by haematite. This stage involved re-addition of several major (except Al and Si) and trace elements. It is seen that although alumo-goethite, kaolinite, and haematite can host significant quantities of several trace elements, alumo-goethite and haematite have a much better potential of immobilizing most trace elements including toxic ones compared to kaolinite in the weathering profile.

Coal usage continues to increase due to global energy demands. Increasing environmental monitoring and concern means that better methods of trace element determination are always required. This study investigated the use of N,N-dimethylformamide (DMF), Triton X-100, HNO 3 and ultrasound to extract trace elements (Cr, Mn, Pb, Sr and V) from coal prior to analysis using ICP-OES and ICP-MS. It was found that the proportion extracted was lowest for V (17%) and highest for Pb (100%). Partial dissolution of the coal particles used in the slurries was demonstrated using scanning electron microscopy studies. Trace element determination of two reference material coal samples demonstrated that this method of extraction is effective. Trace elements in three bituminous coals from different seams being mined in South Africa were determined.

A series of well-characterized specimens, known as the Peabody-Yale Reference Obsidians (PYRO) sets, has been designed to aid with calibrating and assessing X-ray fluorescence analysis (XRF) data, including portable XRF (pXRF) measurements, for obsidian sourcing. Each of these ten matched sets consists of 35 specimens: 20 specimens for calibration and 15 specimens for evaluation. These sets include not only obsidians with common geochemical compositions (i.e., alkaline rhyolites) but also rarer ones (i.e., peralkaline rhyolitic, trachytic, and andesitic specimens, including East African Rift obsidians). When used as described, the PYRO sets are suitable to calibrate and evaluate XRF data for obsidians worldwide. A set can be borrowed following loan policies of the Peabody Museum of Natural History, which will also accession a set. Publishing all source information – from their names and GPS coordinates to the datasets used for the recommended values – not only allows the sets to be replicated by others but also fulfills the demands of scientific transparency. Their main purpose is facilitating collaborations and “big data” projects, and the PYRO sets were designed to complement existing protocols for calibration and evaluation. In short, the sets are intended as a tool for almost anyone (e.g., a student who borrows an instrument to source artifacts) to meet – and even exceed – experts' practices involving transparency, accuracy, and reproducibility.

C and N isotopes (collagen), trace elements (apatite), and WARN modeling conducted on sub-adults from prehistoric İkiztepe.
•The weaning age is suggested enabling greater understanding of the weaning process and population dynamics.
•WARN has emphasised the lag effect in living bone as something to be considered when examining the weaning process.
•Reconsideration of the utility of trace element analyses, and the importance of utilising a holistic approach.

Thallium (Tl) isotope compositions of ocean island basalts (OIBs) have been proposed as a novel tracer of subducted ocea-nic crust and sediments in ocean island basalt sources, which could act as direct confirmation that deep mantle recycling eventually resurfaces through mantle upwelling to form ocean island basalt magmatism. However, it is unknown if oceanic crust that went through an active subduction zone would retain the Tl isotope compositions recorded in hydrothermally altered oceanic crust and authigenic marine sediments. In this study we present Tl isotope and concentration data for samples of sub-ducted oceanic crust from five different locations: Zambezi Belt, Zambia; Cabo Ortegal complex, Iberian Massif, Spain; Ras-pas Complex, southwest Ecuador; Syros island, Cyclades, Greece; Tian Shan, northwest China. Thallium concentrations in most samples follow strong linear relationships with K, Rb, Cs and Ba, which strongly suggest that the mineral phengite is the primary control of Tl abundances in subducted oceanic crust. This conclusion is consistent with recent Tl data sets for arc lavas that imply residual phengite in the arc lava source regions as a strong control of Tl recycling. We find that Tl isotope compositions vary widely and systematically in each location depending on the protolith, metamorphic and metasomatic history of the samples. Samples from Cabo Ortegal and Raspas Complex reveal Tl isotope compositions similar to their pro-toliths, which were comprised of low-temperature altered oceanic crust. Tian Shan metamorphic rocks and Zambian eclogites reveal invariant Tl isotope values indistinguishable from average mantle, which is best explained by overprinting by metamorphic fluids that contained high concentrations of Tl and other alkali metals. Samples from Syros reveal a range of Tl isotope compositions from normal mantle towards values for pelagic clay sediments. The sediment-like values in Syros likely arose from fluids released from the surrounding mélange matrix that consists of serpentinite, metagabbros and metased-iments. Each of the three Tl isotope ranges observed for subducted oceanic crust samples here are mirrored by individual OIB locations. Cabo Ortegal and Raspas Complex display Tl isotope compositions identical to St. Helena, suggesting that the HIMU component likely comprises subduction modified low-temperature altered oceanic crust. Thallium isotope ratios in Zambia and Tian Shan eclogites and blueschists are identical to lavas from Iceland, whereas Syros metamorphic rocks overlap almost exactly with lavas from Hawaii. Our data, therefore, show that Tl isotope compositions of oceanic crust and sediments can be traced through the subduction process and eventually is expressed largely unmodified in ocean island basalts.

Arctic and subarctic environments are particularly sensitive to climate change with a faster warming compared to other latitudes. Vegetation is changing but its role on the biogeochemical cycling is poorly understood. In this study, we evaluated the distribution of trace elements in subarctic soils from different land covers at Abisko, northern Sweden: grassland, moor, broad-leaved forest, and peat bog. Using various multivariate analysis approaches , results indicated a spatial heterogeneity with a strong influence of soil horizon classes considered: lithogenic elements (e.g., Al, Cr, Ti) were accumulated in mineral horizon classes and surface process-influenced elements (e.g., Cd, Cu, Se) in organic horizon classes. Atmospheric influences included contamination by both local mines (e.g., Cu, Fe, Ni) and regional or long-range atmospheric transport (e.g., Cd, Pb, Zn). A non-negative matrix factorization was used to estimate, for each element, the contribution of various sources identified. For the first time, a comparison between geochemical and ecological data was performed to evaluate the influence of vegetation on element distribution. Apart from soil pH that could control dynamics of As, Cu, and Se, two vegetation classes were reported to be correlated to geochemical factors: forbs and shrubs/dwarf shrubs probably due to their annual vs. perennial activities, respectively. Since these are considered as the main vegetation classes that quickly evolve with climate change, we expect to see modifications in trace element biogeo-chemical cycling in the future.

Gunung Masurai adalah salah satu gunung api yang terletak di Kabupaten Merangin, Provinsi Jambi, Indonesia. Studi mengenai Gunung Masurai masih sangat terbatas. Hal ini dapat dilihat dari jumlah literatur dan paper penelitian mengenai Gunung Masurai masih sangat minim. Padahal penelitian mengenai gunung api sangat penting untuk deteksi dini terhadap bencana alam, seperti letusan gunung api dan gempa bumi. Periode letusan gunung api dapat diprediksi melalui penelitian yang komprehensif dan intensif terhadap gunung api sehingga tindakan pencegahan yang tepat dapat dipersiapkan untuk meminimalisasi jumlah korban dari bencana alam tersebut. Dalam penelitian ini, telah dilakukan studi mengenai analisis geokima batuan vulkanik dari Gunung Masurai. Sampel batuan tersebut dikarakterisasi menggunakan XRF ARL9900 untuk unsur-unsur utama. Sedangkan untuk unsur-unsur jejak dan logam tanah jarang dikarakterisasi menggunakan ICP-MS. Kemudian sampel paleosol dan karbon dikarakterisasi menggunakan alat C-14 dating untuk menentukan penanggalan. Berdasarkan hasil pengolahan data geokimia maka diperoleh secara umum batuan ignimbrite memiliki komposisi SiO2 dalam rentang (60,00 – 78,00)%. Hal ini masih memiliki kecenderungan konten SiO2 yang karakteristik untuk satuan batuan pada Island arc tholeiites (45,00 – 70,00)%. Sedangkan untuk sampel batuan beku dan lava flow dari Gunung Masurai termasuk dalam seri Medium Calc-Alkaline sampai High Calc-Alkaline, dan memiliki konten SiO2 dalam kisaran (51,00 – 69,00)%, MgO (1,00 - 6,00)%, FeO (2,00 – 9,00)%, TiO2 (0,30 – 1,00)%, dan Al2O3 (13,00 – 18,00)%. Sedangkan K2O berkisar antara (0,80 – 3,00)% dengan rasio FeO * / MgO sekitar 1,48% hingga 4,50%. Sementara untuk sampel Tuff dan Tephra yang dianalisis memiliki konten SiO2 dalam kisaran (52,00 – 70,00)%, MgO (0,10 - 1,80)%, FeO (2,00 – 9,00)%, TiO2 (0,80 – 12,00)%, dan Al2O3 (15,00 – 42,00)%. Sedangkan K2O berkisar (0,10 - 2,30)%. Ini mungkin berkorelasi dengan vulkanik pasca-YTT (Youngest Toba Tuff) yang memiliki rentang konten SiO2 (52,00 – 76,00)%. Sedangkan berdasarkan hasil karakterisasi C-14 dating diperoleh umur 32,786 calBP untuk bagian utara Gunung Masurai sementara batuan dari bagian selatannya berumur 21,335 calBP. Hal ini dapat diinterpretasikan bahwa Gunung Masurai telah mengalami dua periode letusan. Namun, penelitian lebih lanjut perlu dilakukan untuk menghasilkan data yang lebih representatif dengan keyakinan geologi yang tinggi.

Kata-kata kunci: Gunung Masurai, ignimbrite, geokimia, vulkanik, unsur utama, carbon dating

Data are presented to demonstrate that the circumpulpal dentine of deciduous teeth can be used to reconstruct a detailed record of childhood exposure to lead. By combining high spatial resolution laser ablation ICP-MS with dental histology, information was acquired on the concentration of lead in dentine from in utero to several years after birth, using a true time template of dentine growth. Time corrected lead analyses for pairs of deciduous molars confirmed that between-tooth variation for the same child was negligible and that meaningful exposure histories can be obtained from a single, multi-point ablation transect on longitudinal sections of individual teeth. For a laser beam of 100 μm diameter, the lead signal for each ablation point represented a time span of 42 days. Simultaneous analyses for Sr, Zn and Mg suggest that the incorporation of Pb into dentine (carbonated apatite) is most likely controlled by nanocrystal growth mechanisms. The study also highlights the importance of discriminating between primary and secondary dentine and the dangers of translating lead analyses into blood lead estimates without determining the age or duration of dentine sampled. Further work is in progress to validate deciduous teeth as blood lead biomarkers.

University of Hawaiʻi at Mānoa researchers funded by two National Science Foundation (NSF) programs are working with a third-generation farming family to better understand challenges to their livelihoods and those of other small farmers on Oʻahu. Active Societal Participation in Research and Education (ASPIRE), and ʻIke Wai, a program that studies Hawaiʻi‘s aquifers with a goal of ensuring future water security, are partnering to make this possible.

This paper aims to advance previous studies on the iron and manganese content in groundwater of Rrogozhina aquifer (western Albania) and to show the factors which control the content of both iron and manganese in groundwater of this aquifer. Rrogozhina aquifer represents an important groundwater source of the country whose relevance was highly increased during recent years because of the demographic expansion in this region. This is a typically multi-layered artesian aquifer which consists of sandstone and conglomerate with high heterogeneous permeability. The groundwater mostly belongs to HCO3-Mg-Ca hydrochemical type. The content of soluble iron and manganese in groundwater ranges from 0.004 mg/L to 0.7 mg/L, and from 0.0 mg/L to 1.147 mg/L, respectively. Deeper the groundwater occurs and longer the distance from the recharge zone, higher is the content of Fe2+  in groundwater due to gradual depletion of O2 in groundwater. The content of iron is higher than that WHO and EU recommended, which were 21% and 25% respectively, while the content of manganese were 17% and 23%, respectively. Abstraction of groundwater with high quantities by deeper wells would be accompanied by increase of dissolved iron and manganese content in groundwater which should be treated (with aeration) in order to decrease the content of these two elements in the water before using it.

Potentially toxic element contents in agricultural soils were assessed by comparison with levels recorded in the literature and evaluated using Index of Geoaccumulation (Igeo). The model recommended by United States Environment Protection Agency is applied for the health risk assessment from different exposure pathways. The median values of cobalt (Co), chromium (Cr) and nickel (Ni) exceeds about 2, 3 and 14 times, respectively, the corresponding values given by the Geochemical Atlas of Europe project, however, they present low potential ecological risk. The median values of manganese (Mn) and vanadium (V) are slightly lower than the corresponding values given by the Geochemical Atlas of Europe project. Risk assessment results present negligible health risk to children and adults due to manganese (Mn), nickel (Ni) and vanadium (V) exposure through ingestion of contaminated soil. Only the cobalt (Co) hazard quotient (HQ) and hazard index (HI) for children around two sampling sites exceed the acceptable safe risk level.

The main goal of the research was to determine to which extent the copper (Cu) is dominant in the topsoils of Tuzla's area. Considering the defined goal, the detailed soil analyze for the presence of this element in the area of Tuzla, was carried out. The terrain work was based on soil sampling (240 samples) from the area of about 303 km2. The sampling network for the urban part of the town was 1x1 km, and for the rural part 1, 5x1, 5 km and according to URGE instructions. The Cu concentrations are obtained by the most sophisticated laboratory method (ICP-MS), with a highly sensitive detection threshold (0.02 to 10,000 ppm). Elevated concentrations of copper in the Tuzla’s topsoil are recorded in 64 samples. The copper concentrations in these samples ranges from 50 ppm to 156, 1 ppm. Highly exceeded concentrations are recorded in samples No: 64, 66, 163, 170, 171, 182, 187, 195, 214 and 249a, located mostly in the western part of the Tuzla. The increased concentrations copper are primarily a consequence of anthropogenic impacts in enviroment.

Ancient Roman architecture has a global legacy, but its early development was shaped by highly specific, local factors. One crucial feature in this development was the exploitation of the various volcanic stones ("tuffs") found within a 25 km radius of the center of Rome. Already in the Archaic period (sixth century B.C.E.), the tuff bedrock of Rome's seven hills was being quarried for architectural use; by the Late Republic (first century B.C.E.) at the latest, Roman architects were building with a variety of tuffs quarried well beyond the city's limits, some from the territories of bested former rivals. Roman architecture of the Archaic and Republican periods developed in dialogue with its Etruscan and Latin neighbors, many of whom similarly employed locally quarried tuffs. None of Rome's neighbors, however , came to employ such a wide variety of tuffs, nor did they generally import nonlocal materials. The differing physical properties of the various tuffs allowed Roman builders to experiment, and by the late third century B.C.E. at the latest, they were strategically employing different tuffs to meet specific constructional and decorative needs. Despite decades of archaeological and historiographic work in Rome and its tufaceous catchment area, however, contemporary understanding of tuff use still relies on century-old studies: Tenney Frank's groundbreaking "Notes on the Servian Wall," which established the basic tuff typology used by archaeologists today, was published in 1918 (AJA 22: 175-88). Frank's classification was based largely on macroscopic identification of tuffs; as the results of recent geochemical studies have proven, however, visual inspection alone is insufficient to provenance tuff reliably. Nor is extraction of mineral resources simply a material correlate of the expansion of Roman state power, contrary to Frank's hypotheses. Given recent advances in archaeological science and decades of historiographic reflection, the time is ripe for a comprehensive restudy of the Roman tuffs. Accordingly , we have undertaken a new project, "QUarry provenance and Archaeological Dating of the Roman-Area Tuffs in Antiquity." QUADRATA combines a campaign of trace-element analysis, in order to pinpoint provenience of various tuffs from known ancient quarries in the hinterland of Rome, with a consideration of the Republican architectural contexts employing tuff and a historiographic study of early Roman construction and resource extraction. A pilot study involving geo-chemical and petrographic analysis of tuffs from the temples of Fortuna and Mater Matuta at Sant'Omobono has already been completed. We will discuss some of the implications of the results of this study, along with challenges and prospects for future work.

The early Late Miocene vertebrate locality of Rudabánya II (R. II) in northeastern Hungary preserves an abundance of forest-adapted ungulate species. To better understand the ecological relationships within this ancient ecosystem, we used analysis of enamel strontium/calcium (Sr/Ca) ratios to infer dietary preferences. The goals of the analysis were to: i) determine whether these ungulate species specialized in specific plants or plant parts; ii) discern whether the Sr/Ca ratios support what was previously suggested about the ecology of these species and iii) evaluate the factors that may have acted to promote coexistence within this diverse community of predominantly browsing herbivores. Results show significant differences in the diets of the sampled species. The highest Sr/Ca ratios were displayed by the suids Parachleuastochoerus kretzoii (fortelius et al., 2005) and Propotamochoerus palaeochoerus (pilgrim, 1926) implying a preference for Sr-rich underground plant parts. Elevated Sr/Ca ratios yielded by the cervid Lucentia aff. pierensis (thomas, 1951) and equid Hippotherium intrans (kretzoi, 1983) are indicative of intermediate feeding. The bovid Miotragocerus sp. (stromer, 1928) showed higher Sr/Ca ratios than the gomphothere Tetralophodon longirostris (kaup, 1832), which is incongruent with morphological and stable isotope data, and suggested browsing by both taxa. This finding is likely the result of a difference in digestive physiology (ruminant vs. monogastric) rather than a difference in dietary behaviour. The lowest Sr/Ca ratios were displayed by the traguild Dorcatherium naui (kaup and scholl, 1834) and moschid Micromeryx flourensianus (lartet, 1851) suggesting a preference for Sr-poor fruits. Resource specialization and partitioning within the local environment likely acted to decrease interspecific competition and promote coexistence within the diverse ungulate community at R. II.

Mantle-derived peridotites sampled at three dredge sites between the Discovery and Indomed fracture zones on the Southwest Indian Ridge axis are analyzed for petrography and major and trace element mineral compositions. While textures and microstructures are those typical of normal residual peridotites these rocks display a large compositional variation encompassing the whole spectrum of abyssal peridotites even at the scale of a single dredge site (≤ 1 km). Particularly, clinopyroxenes in peridotites dredged at 44.03°E show a huge variation in sodium contents positively correlated with chromium concentrations. Observed Na\ \Cr enrich-ments exceed the commonly reported contents of the spinel abyssal peridotites. Similar values are also found in very few peridotite samples collected at ultra-slow spreading ridges. Major substitutions governing the compositions of these clinopyroxenes suggest that Na\ \Cr covariation is caused by a more rapid decrease in Al-Tschermak's molecule with respect to the sodic components jadeite ± kosmochlor, as Cr/Al increases and modal clinopyroxene decreases. We conclude that sodium and chromium enrichments must have occurred contemporaneously with aluminum depletion, i.e., during partial melting. Our modelling suggests that partial, non-modal, melting of a depleted peridotite in association with addition of sodium, by percolation of a Na-rich melt in the upwelling mantle, or Na diffusion from a nearby alkaline melt, may explain this enigmatic and counterintuitive trend.

In this study we investigate the origin and alteration history of serpentinites in two dredge hauls from the North Wall of the Puerto Rico Trench, where the North American plate subducts beneath the Greater Antilles island arc. Faulting of the North American plate at the North Wall of the Puerto Rico Trench exposes oceanic basement in a nearly spreading-parallel direction, offering a unique perspective on crustal accretion and alteration processes in the Cretaceous Quiet Zone. U–Pb age dating of porous zircon in an altered mafic vein in serpentinite from 20 00'00 " N, 66 31'57 " W yields an age of 114Á8 Ma, suggesting that it originated at the Cretaceous Mid-Atlantic Ridge, c. 2200 km east of its current location. After localized high-temperature (>380 C) hydrothermal alteration to chlorite, antigorite, talc and tremolite, peridotites underwent pervasive serpentinization at lower temperatures ($310–240 C). In addition to lizardite-rich serpentinite, which is prevalent in dredge D10, dredge D2 contains serpentinite dominated by antigorite. Pervasive serpentinization was followed by extensive talc alteration of several antigorite-rich serpentinites from dredge D2, which was accompanied by Fe loss. As the newly formed crust moved off-axis, open-system alteration at low temperatures by seawater (i.e. weathering) modified the mineralogy, chemical composition, and physical properties of the serpentinite. Where present, brucite dissolved and magnetite oxidized to hematite and goethite, which caused a decrease in magnetic susceptibility and an increase in porosity. Weathering led to complete oxidation of several lizardite-serpentinites in dredge D10, whereas talc-altered antigorite serpentinites in dredge D2 were less affected by oxidation. Rare earth element concentrations of lizardite-rich serpentinite in dredge D10 decreased steadily with increasing Fe(III)/Fe tot , reflecting simultaneous leaching and oxidation by seawater. These results have implications for our understanding of several processes, including hydrothermal alteration of peridotite at the Cretaceous Mid-Atlantic Ridge, mass transfer and redox reactions between ser-pentinite and seawater during off-axis weathering, and the introduction of volatiles, oxidizing agents, and antigorite beneath the Greater Antilles Arc.