Geochemistry International最新文献

{"title":"Trace Element Mobility during Hydrothermal Alteration of the Oceanic Crust at Slow-Spreading Ridges","authors":"S. A. Silantyev,&nbsp;I. V. Kubrakova,&nbsp;D. D. Badyukov,&nbsp;E. A. Krasnova,&nbsp;O. A. Tyutyunnik,&nbsp;S. N. Nabiullina,&nbsp;V. V. Shabykova,&nbsp;T. G. Kuzmina","doi":"10.1134/S0016702925601056","DOIUrl":"10.1134/S0016702925601056","url":null,"abstract":"<p>The goal of this work was to assess the nature and agents of the processes that control the mobility of trace elements during hydrothermal alteration of the oceanic crust at slow-spreading ridges. Based on the results of our study, it was concluded that serpentine replacement by talc is widespread in abyssal peridotites in the areas of active hydrothermal fields at slow-spreading ridges. This process results in a sharp decrease in the MgO/SiO₂ ratio of ultramafic rocks. Hydrothermally altered serpentinites collected near active hydrothermal vents show specific geochemical features, including a pronounced positive europium anomaly on the chondrite-normalized REE distribution patterns and (La/Sm)_cn &gt; 1. The final low-temperature stage of recrystallization of hydrothermally altered serpentinites is accompanied by the mobile behavior of Pd and Re (their gain), which provides high contents of these elements in the rock at generally low PGE mobility. The hydrothermal alteration of serpentinites collected near hydrothermal vents may involve organic matter, the source of which could be foraminiferal silts or biota widely developed in Logatchev and Ashadze hydrothermal vents. The established features related to the influence of active hydrothermal vents on the composition of the host serpentinites can be considered as geochemical indicators for the occurrence of serpentinite-hosted hydrothermal fields on the seafloor at slow-spreading ridges.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 4","pages":"273 - 295"},"PeriodicalIF":0.8,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0016702925601056.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fractionation of Noble Metals in Serpentinite-Hosted Hydrothermal Systems","authors":"I. V. Kubrakova,&nbsp;S. A. Silantyev,&nbsp;O. A. Tyutyunnik,&nbsp;S. N. Nabiullina,&nbsp;D. V. Pryazhnikov","doi":"10.1134/S0016702925601196","DOIUrl":"10.1134/S0016702925601196","url":null,"abstract":"<p>Data on the speciation and mechanisms of transport of noble metals (NM) (Au, Ag, Pd, Pt, Rh, Ru, Ir) in oceanic hydrothermal systems were considered and summarized. The contents (0, <i>n</i>–10<i>n</i> ppb) and distribution of NM and Re in the seafloor rocks of the Logatchev and Ashadze hydrothermal fields of the Mid-Atlantic Ridge were determined. The dominance of light chalcophile elements (Au, Pd, Ag, and Re) and high Pd/Ir values were observed in samples taken in close proximity to hydrothermal structures, and the highest Pd/Pt values were obtained for the same samples. Such PGE fractionation may be due to element redistribution during magmatic and postmagmatic transformations under the influence of hydrothermal fluid. According to the obtained data, Au, Pd, and Re could migrate in the form of dissolved complex compounds with inorganic and organic ligands, as well as through pseudocolloid transport of complex and nanometer-sized forms of Au, Pd, and Ag on organomineral particles based on Fe oxyhydroxides. Iridium-group PGE are probably mainly sorbed by organomineral particles from seawater (and its derivatives formed during water percolation through crustal materials). The presence of a positive Rh anomaly in chondrite-normalized PGE distribution patterns was confirmed.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 4","pages":"296 - 308"},"PeriodicalIF":0.8,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Composition, Inner Structure, and Morphology of Zircon as Indicators of the Formation and Evolution Conditions of Ancient Granulite Complexes: An Example of the Pongoma-Navolok Complex in Northern Karelia","authors":"V. M. Kozlovskii,&nbsp;E. B. Kurdyukov,&nbsp;T. F. Zinger,&nbsp;V. V. Travin,&nbsp;S. E. Borisovskii,&nbsp;O. M. Zhilicheva,&nbsp;E. O. Solenikova","doi":"10.1134/S0016702926700011","DOIUrl":"10.1134/S0016702926700011","url":null,"abstract":"<p>The composition, inner structure, and morphology of zircon grains hosted in various rocks of the Archean Pongoma-Navolok granulite–charnockite–charnoenderbite complex in northern Karelia indicate that these features of the mineral are characteristic and, hence, can be used as indicators of petrogenetic processes that produced the rocks. Zircon was determined to have crystallized from charnoenderbite melt only within the range of high temperatures at which the melt was derived. The charnockitization and granitization of the charnoenderbites were associated with the homogenization of the zircon composition, disruption of its structure, and the dissolution and removal of Zr, Hf, and REE from the charnockitization zone. Growth and dissolution zones in the zircon crystals and zircon grain domains suitable for thermometry and isotope dating were identified, and their relative position in the crystals was determined, using a complex of techniques of high spatial resolution. Temperature evaluations based on Hf distribution between the zircon and melt indicate that the mineral has crystallized in the charnoenderbites only during the earliest evolution of the complex at <i>T</i> = 990–1080°C. When the rocks were affected by charnockitization, some zircon grains reached equilibrium with the autochthonous charnockite melt at the temperature of its generation of <i>T</i> = 790–850°C.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 4","pages":"239 - 262"},"PeriodicalIF":0.8,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry of Clinopyroxenes from Kamafugites of the Bunyaruguru Volcanic Field, East African Rift","authors":"N. S. Muravyeva,&nbsp;S. G. Simakin,&nbsp;V. G. Senin","doi":"10.1134/S001670292560124X","DOIUrl":"10.1134/S001670292560124X","url":null,"abstract":"<p>The paper presents pioneering data on the trace-element (Cr, Rb, Sr, Zr, Ba, Ce, Sm, Gd, Er, Yb, Hf, U, Th, Lu, Dy, Eu, Nd, and La) composition of clinopyroxenes in phenocrysts and xenoliths from ultrapotassic rocks of the Bunyaruguru volcanic field, Toro-Ankole Province, East African Rift. Contents of trace elements in clinopyroxenes from individual volcanoes within the Bunyaruguru volcanic field are different: clinopyroxenes from the Nyungu crater are enriched in Zr (up to ∼1000 ppm), whereas clinopyroxenes from the Kazimiro crater are enriched in Nb (up to ∼30 ppm). The obtained results led us to estimate crystallization parameters of the clinopyroxenes, clarify differences in the composition of kamafugite lava sources, and identify the different types of mantle metasomatism within a single volcanic field.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 4","pages":"309 - 322"},"PeriodicalIF":0.8,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical Composition of Metallic Iron Spherules in the Chang’e-5 Lunar Soil","authors":"E. M. Sorokin,&nbsp;M. V. Gerasimov,&nbsp;V. Ya. Shklover,&nbsp;A. V. Bondarev","doi":"10.1134/S0016702925600968","DOIUrl":"10.1134/S0016702925600968","url":null,"abstract":"<p>Nanophase iron metal (npFe⁰) spherules ranging in size from a few to hundreds of nanometers are a significant component of the regolith of the Moon and other airless bodies affecting the spectrum of electromagnetic wave reflection. Electron microscopy was used to study nanospherules on the surface and within the volume of agglutinate particles from the lunar regolith of Rümker Mons returned to the Earth by the Chang’e-5 mission. The glass hosting the npFe⁰ spherules was characterized by a noticeable oxygen depletion compared with the surrounding unmelted minerals. The oxygen deficiency of the glass contributed to the formation of npFe⁰ and the reduction of elements with low affinity for oxygen, in particular, siderophile elements and sulfur. The spherules were enriched in siderophile elements, including Ni and P, and S relative to the host glass. It can be hypothesized that the increased contents of siderophile elements and sulfur are due to the sorption of their reduced species by iron spherules formed in the glass during active mixing of boiling melt produced by a high-speed impact. The feeding glass zone from which these elements were sorbed was estimated to be up to 3–4 radii of the spherules. Thus, npFe⁰ spherules can act as a kind of repository for siderophile elements and sulfur or as their carrier, when the spherules were ejected into the impact-related vapor cloud.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 3","pages":"163 - 181"},"PeriodicalIF":0.8,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal Variability of the Elemental Composition and Ecological Risks of Urban Dust of Moscow Megacity","authors":"A. I. Ivaneev,&nbsp;A. S. Brzhezinskiy,&nbsp;V. K. Karandashev,&nbsp;M. S. Ermolin,&nbsp;P. S. Fedotov","doi":"10.1134/S0016702925600701","DOIUrl":"10.1134/S0016702925600701","url":null,"abstract":"<p>For the first time, a study was conducted to examine seasonal variations in the elemental composition of urban dust in Moscow, Europe’s largest metropolis, as well as the risks to ecosystems and resident health associated with the accumulation of anthropogenic elements in dust. Urban dust samples were collected in the city center in spring, summer, and autumn, 2024, and their elemental composition was subsequently determined. Twelve urban dust samples were collected in each season. The calculation of enrichment factor and geoaccumulation index revealed that urban dust in Moscow is contaminated with V, Bi, Mo, Sn, Cd, Cu, Pb, S, Ca, Zn, W, and Sb, and the degree of their accumulation varies with season. Spring urban dust samples were found to be most contaminated with S, Ca, and W, summer dust samples, with Cd, Pb, Bi, Cu, and Sb, and autumn dust samples, with Mo, Sn, Zn, Bi, Cu, and Sb. The assessment of potential ecological risks demonstrated that the highest degree of pollution and a significant degree of potential ecological risk (300 &lt; RI &lt; 600) are characteristic of summer urban dust in Moscow (RI = 521), followed by autumn (RI = 367) and spring (RI = 271) urban dust. The identified differences in the degree of pollution and potential environmental hazard of the studied dust samples can be caused, mainly, by changes in the degree and characteristics of the anthropogenic impact of the metropolis on the environment depending on the season. For all the studied dust samples, regardless of the season, an alarming level of possible potential non-carcinogenic risks for children (CHI &gt; 1.1) and an alarming level of possible potential carcinogenic risks to human health (CTCR &gt; 1.1 × 10^–4) were shown. It is shown that the health risks associated with urban dust pollution at different times of the year are comparable.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 3","pages":"220 - 235"},"PeriodicalIF":0.8,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimates of the Catagenesis Grades of Rocks in Different Modeling Systems: An Example of the Sedimentary Sequence of Well Ostaninsky 438, Tomsk Region, West Siberian Basin","authors":"Yu. I. Galushkin","doi":"10.1134/S0016702925600506","DOIUrl":"10.1134/S0016702925600506","url":null,"abstract":"<p>Calculations of the vitrinite reflectance (%Ro) and the hydrocarbon generation by the probable source rocks in the Ostaninsky area of the West Siberian basin demonstrate noticeable differences in TeploDialog and GALO estimates of the maturation degree of the organic matter, hydrocarbon generation, and the chronological sequence of the generation of liquid and gaseous hydrocarbons. It is important that both the TeploDialog and the GALO modeling systems make use of the same data on the modern sedimentary sequence of the basin and the same measurements of rock temperatures and vitrinite reflectance in this sequence. Calculations with the application the thermochronologic evolution of the formations reconstructed by the paleotemperature method in the TeploDialog system suggest that the generated liquid hydrocarbons had completely degraded during the period of high heat flow from the Silurian to the Permian and that the rocks of the Larinskaya, Mirnaya, and Chuzik formations are gas-generating in terms of generation characteristics. In the thermochronologic evolution of these formations reconstructed by the GALO system, the main thermal impulse comes from the emplacement of a sill near the basement subsurface in the Jurassic. Because of this, HC were generated mostly during and/or after sill emplacement. The maturity of organic matter calculated for all the formations in the GALO system from the thermochronologic evolution is noticeably lower than that calculated from the temperature histories in the TeploDialog system. As a result, the GALO modeling predicts that even the rocks of the Mirnaya Formation are capable of oil generating according to their generation characteristics, the rocks of the Chuzik Formation can be considered as predominantly oil-generating, and the rocks of the Chaga Formation are interpreted as oil-generating. The TeploDialog modeling of the thermochronologic evolution assumes that the Jurassic “Bazhenov oil” is the main source of hydrocarbons for crustal and Paleozoic reservoirs, whereas the GALO modeling of this history and the calculations of hydrocarbon generation indicate that oil was generation by Domanik-like rocks (for example, the rocks of the Chaga Formation). The examples of modeling discussed in this paper demonstrate that the oil and gas potentials of basins should be assessed with caution when using modeling systems in which the heat flow is specified for relatively shallow depths (in the bottom part of the sedimentary sequence).</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 3","pages":"195 - 206"},"PeriodicalIF":0.8,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum to: The Systems CaSiO3–CaF2 and Ca0.5Mg0.5SiO3–CaF2 at 6 GPa","authors":"A. Shatskiy,&nbsp;A. V. Kovalenko,&nbsp;Yu. G. Vinogradova,&nbsp;D. V. Shatskaya,&nbsp;K. M. Stepanov,&nbsp;D. E. Sidko,&nbsp;G. N. Ovsyannikov,&nbsp;C. A. Lorenz,&nbsp;M. A. Nikitin","doi":"10.1134/S0016702926250026","DOIUrl":"10.1134/S0016702926250026","url":null,"abstract":"","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 3","pages":"237 - 237"},"PeriodicalIF":0.8,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0016702926250026.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum to: Formation and Evolution of Spinel Anorthosite on the Moon: Experiment and Observation on Lunar Highland Meteorites Dhofar 025, Dhofar 311, and NWA 11303","authors":"L. A. Lakhmanova,&nbsp;S. I. Demidova,&nbsp;V. G. Butvina,&nbsp;M. A. Golunova,&nbsp;P. Y. Plechov,&nbsp;P. G. Bukhtiyarov,&nbsp;K. V. Van,&nbsp;G. S. Nikolaev","doi":"10.1134/S0016702926250014","DOIUrl":"10.1134/S0016702926250014","url":null,"abstract":"","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 3","pages":"236 - 236"},"PeriodicalIF":0.8,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0016702926250014.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluorwavellite: A Physicochemical Study and Thermodynamic Characteristics","authors":"Yu. D. Gritsenko,&nbsp;L. P. Ogorodova,&nbsp;S. V. Vyatkin,&nbsp;M. F. Vigasina,&nbsp;D. A. Kalinyuk,&nbsp;L. V. Melchakova,&nbsp;D. A. Ksenofontov","doi":"10.1134/S001670292560107X","DOIUrl":"10.1134/S001670292560107X","url":null,"abstract":"<p>A comprehensive physicochemical study of fluorwavellite Al₃(PO₄)_2.1(OH)_1.9F_0.8⋅5.5H₂O (from the Ulytau region, Kazakhstan) was carried out using powder X-ray diffraction, electron probe microanalysis, FTIR, Raman and EPR spectroscopy, and thermogravimetry. The enthalpy of formation of the studied fluorwavellite from elements was determined for the first time using high-temperature melt solution calorimetry in a Calvet microcalorimeter (–6606 ± 12 kJ/mol). The value of its standard entropy was estimated and the Gibbs energy of formation was calculated (483.4 J/(mol K) and –5941 ± 12 kJ/mol, respectively). The thermodynamic constants of the end members of the isomorphic series wavellite Al₃(PO₄)₂(OH)₃⋅5H₂O–fluorwavellite Al₃(PO₄)₂(OH)₂F⋅5H₂O were estimated: <span>({{Delta }_{f}}H_{{{text{el}}}}^{0})</span> (298.15 K) = –6328 ± 12 and –6435 ± 12 kJ/mol, <i>S</i>⁰(298.15 K) = 464.3 and 463.0 J/(mol K), <span>({{Delta }_{f}}G_{{{text{el}}}}^{0})</span> (298.15 K) = –5674 ± 12 and –5801 ± 12 kJ/mol, respectively.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"64 3","pages":"182 - 194"},"PeriodicalIF":0.8,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}