Chemie Der Erde-Geochemistry最新文献

{"title":"Late Jurassic to Early Cretaceous mafic to felsic magmatism reveals the coupled processes of crustal growth and thinning in Southeast China","authors":"Yulin Wang ,&nbsp;Jinbao Yang ,&nbsp;Xijun Liu ,&nbsp;Hongxia Yu ,&nbsp;Zhenglin Li ,&nbsp;Tengpeng Li ,&nbsp;Zhenzhen Xu ,&nbsp;Yiting Yuan","doi":"10.1016/j.chemer.2025.126314","DOIUrl":"10.1016/j.chemer.2025.126314","url":null,"abstract":"<div><div>The study investigates the petrogenesis, deep magmatic processes, and tectono-magmatic evolution of Late Jurassic to Early Cretaceous mafic-felsic igneous rocks from the Guangdong-Fujian border area in Southeast China, using detailed field, petrographic observation, zircon U-Pb geochronology, Hf isotopes geochemistry, bulk-rock major-trace elements and Sr-Nd isotope geochemistry. Zircon U-Pb dating reveals three distinct magmatic activities. The Late Jurassic (ca. 152 Ma) granitoids, identified as fractionated both I-type and A-type granites, exhibit low ε_Hf (t) (−8.3 to −1.9) values and enriched Sr-Nd isotopes that are consistent with melting of psammitic sources. The Late Cretaceous complex (ca. 105 Ma) with initial ⁸⁷Sr/⁸⁶Sr ratios (0.7059 to 0.7067) and ε_Nd (t) values (−4.0 to −2.9), together with relatively high ε_Hf (t) values (−5.6 to 1.4), suggesting binary mixing of melts from psammitic and basaltic sources. The Cenozoic mafic rocks display varied ⁸⁷Sr/⁸⁶Sr ratios (0.7048 and 0.7096) and positive ε_Nd (t) values (4.0 and 1.0), indicating an asthenospheric mantle source. Fractional crystallization played a key role in the magmatic evolution of the rocks. The Late Jurassic magmatism may indicate that Southeast China was primarily under a setting of lithospheric extension since 152 Ma, driven by slab rollback. The Late Cretaceous magmatism reflects large-scale lithospheric extension and thinning, triggered by a change in the subduction direction of the Palaeo-Pacific slab from oblique to parallel with the continental margin. Our data suggest that the rollback of the subducted Palaeo-Pacific slab in the Guangdong-Fujian border region created a back-arc extensional setting, leading to substantial crustal thinning. The extension-induced melting of the middle to lower crust, combined with mantle-derived basaltic magma underplating, were primary drivers of granitoid magmatism in Southeast China during the Late Jurassic to Early Cretaceous. In the extensional environment, crustal growth and thinning were interconnected, forming a unified geological process.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126314"},"PeriodicalIF":2.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrothermal carbonate chimney event from yin’ e basin: Mineralogy, geochemistry, and mode of evolution","authors":"Tianxin He ,&nbsp;Rong Liu ,&nbsp;Qianghao Liu ,&nbsp;Hongliang Dang ,&nbsp;Xu Wang","doi":"10.1016/j.chemer.2025.126266","DOIUrl":"10.1016/j.chemer.2025.126266","url":null,"abstract":"<div><div><span><span>Hydrothermal chimney, one of Earth's most mysterious geological events, is crucial for understanding Earth's systems and the history of life. Fine-scale studies of these events help us better understand geological processes, though their transient and complex nature presents significant challenges. Through TIMA, LA-ICP-MS in-situ elemental testing, and Sr and S isotope testing, a relatively complete picture of a carbonate chimney event in the upper section of the Bayingebi Formation in the Yin'e Basin was revealed with high precision. This event was divided into four distinct stages: the prehydrothermal eruption stage, the initial hydrothermal eruption stage, the strong hydrothermal eruption stage and the sustained hydrothermal overflow stage. The pre-hydrothermal eruption stage (Area I) indicates dominant terrigenous sedimentation in a low-energy hydrodynamic environment, with coarse-crystalline </span>calcite enriched in Mn and depleted in K, Na, and Sr and featuring high </span>⁸⁷Sr/⁸⁶Sr values. Subsequently, a transient hydrothermal eruption initiated the deposits in Area II, marked by the appearance of thin-plate calcite and dolomite. During the strong hydrothermal eruption stage (Area III), radial pyrite intersected with calcite, and extensive dolomite precipitation occurred. The ⁸⁷Sr/⁸⁶Sr ratio and the δ³⁴S_V-CDT<span><span> value observed may have been a result of the activities of sulfate-reducing bacteria (SRB). In the sustained hydrothermal overflow stage, the eruption intensity decreased, leading to the formation of abundant microcrystalline carbonates in Area IV. Results show regular changes in hydrothermal mineral combinations, eruption modes, material composition, depositional environments, etc., in each stage of the carbonate chimney event, which can provide important information for global lacustrine </span>hydrothermal activity research.</span></div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126266"},"PeriodicalIF":2.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polymetallic interactions of Zn-Pb-Cu in blue/green-colored speleothems from Malaval Cave (France)","authors":"Martin Vlieghe ,&nbsp;Gaëtan Rochez ,&nbsp;Stéphane Pire-Stevenne ,&nbsp;Alexandre Felten ,&nbsp;Marie Dechamps ,&nbsp;Sébastien R. Mouchet ,&nbsp;Francesca Cecchet ,&nbsp;Olivier Bruguier ,&nbsp;Jean-Louis Galéra ,&nbsp;Gipsi Lima-Mendez ,&nbsp;Marc Llirós Dupré ,&nbsp;Johan Yans","doi":"10.1016/j.chemer.2025.126285","DOIUrl":"10.1016/j.chemer.2025.126285","url":null,"abstract":"<div><div>Speleothems rarely exhibit stunning colors such as red, yellow, green, or blue. The colorations are often linked to elevated heavy metal ion concentration in the drip water and thus to a metal source/pollution in the catchment area. Here the blue-green speleothems coloration in Malaval Cave (Lozère, France) is characterized by a wide panel of optical, mineralogical and geochemical techniques. These techniques were applied on several small blue or white stalactites and a larger greenish stalactite. The speleothems are mostly composed of aragonite and contain variable amounts of Zn, Cu and Pb, which cause the colorations. Zn and Cu are mostly present in substitution in the aragonite and Cu²⁺ is the main cause of the blue coloration. Zn is also found in small amorphous gel particles, containing minor amounts of Mg, Cu and Si. These phases are responsible for microscopical scale variations in the blue coloration. Pb is present as Pb²⁺ ions in substitution within the aragonite, creating a saturated blue-to-greenish coloration. This coloration may depend on the Pb/Zn ratio due to metallic interaction. Pb, Zn and Cu ratios indicate that Pb likely deposited from distinct fluids and at a different timing than Cu and Zn. All three metals likely originate from the leaching of Pb<img>Zn ores in the Jurassic formations surrounding the cave.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126285"},"PeriodicalIF":2.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Permo-Triassic magmatism in the Damaraland Igneous Province, NW Namibia: The Ondurakorume alkaline‑carbonatite complex","authors":"Andreja Ladisic ,&nbsp;Michael A.W. Marks ,&nbsp;Benjamin F. Walter ,&nbsp;R. Johannes Giebel ,&nbsp;Aratz Beranoaguirre ,&nbsp;Gregor Markl","doi":"10.1016/j.chemer.2025.126287","DOIUrl":"10.1016/j.chemer.2025.126287","url":null,"abstract":"<div><div>The four spatially associated igneous complexes of Kalkfeld, Ondurakorume, Osongombo and Etaneno are situated within the Damaraland Igneous Province (northwestern Namibia), which formed in response to the rifting of the South Atlantic during the early Cretaceous. Spatially-resolved LA-ICP MS U-Pb age dating on zircon and titanite confirms the Cretaceous age for Etaneno (mean of 139.2 ± 6.7 Ma), while Triassic and Permian emplacement ages are indicated for nepheline syenites from Kalkfeld (249.6 ± 3.2 and 249.4 ± 2.9 Ma) and Ondurakorume (272.1 ± 1.5 Ma). Furthermore, apatite ages for nepheline syenites from Etaneno (mean of 122.8 ± 3.8 Ma) and Kalkfeld (217.4 ± 24.5 Ma), and for carbonatites of Ondurakorume (248.1 ± 4.8 Ma) broadly agree with the zircon and titanite ages, while apatite from basement marbles yields a presumably metamorphic age of 479.6 ± 2.6 Ma and 465.1 ± 7.0 Ma.</div><div>Detailed petrographic analysis of syenites, nepheline syenites, carbonatites, silicocarbonatites and fenites from Ondurakorume reveals variable interaction processes between alkaline-silicate rocks and carbonatites. Syenites and nepheline syenites contain interstitial calcite with burbankite or carbocernaite inclusions (as commonly found in calcite carbonatites) and baddeleyite-zircon replacement textures. In some carbonatites and in silicocarbonatites, local contamination with (nepheline) syenites and granitic basement caused elevated Si activity, triggering enhanced formation of clinopyroxene, amphibole and mica.</div><div>Compositional variations in the released fenitizing fluids are indicated by clinopyroxene compositions that vary from nearly end-member aegirine (Aeg_69-91Di_0-10Hed_0-7) in proximal fenites to less sodic aegirine-augite (Aeg_54-96Di_0-17Hed_0-16) in more distal fenite samples, with the latter containing additional sodic amphibole. Compared to clinopyroxene in nepheline syenites and carbonatites, clinopyroxene in fenites shows elevated Ti contents (mostly &gt;0.05 apfu Ti) that are highest in distal fenites (up to 0.22 apfu Ti), suggesting Ti mobility. These changes suggest either a compositional evolution during fluid-rock interaction or two different fluid sources (carbonatites and (nepheline) syenites, respectively).</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126287"},"PeriodicalIF":2.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"The petrology and geochemistry of the Montagna Grande-Monte Gibele trachytic shield volcano (Pantelleria, Italy)","authors":"John C. White ,&nbsp;Ray Macdonald ,&nbsp;Pierangelo Romano ,&nbsp;Bogusław Bagiński ,&nbsp;Silvio G. Rotolo ,&nbsp;Beata Marciniak-Maliszewska ,&nbsp;Alessandra Cinquegrani","doi":"10.1016/j.chemer.2025.126288","DOIUrl":"10.1016/j.chemer.2025.126288","url":null,"abstract":"<div><div>The 45.7 ± 1.0 ka (2σ) eruption of the compositionally zoned (comenditic trachyte to pantellerite) Green Tuff ignimbrite on the volcanic island of Pantelleria, Italy, was followed by the extrusion of a series of post-caldera metaluminous to mildly peralkaline trachyte lavas between 26.2 ± 2.0 and 22.3 ± 2.9 ka (2σ). This study uses whole-rock major- and trace-element compositions, mineral compositions, geothermobarometry, and petrogenetic models to examine the role of trachytes in the evolution of the Pantelleria magma system. Although previous studies have suggested that all of these units are consanguineous and form a liquid line of descent (LLOD) from metaluminous trachyte to peralkaline trachyte and pantellerite, mineralogical and geochemical evidence, as well as the results of modelling, suggest a much more complex origin. The crystallization of alkali feldspar from metaluminous trachyte liquids (descended from alkali to transitional basaltic magma <em>via</em> fractional crystallization) drives the composition of the residual melt to increasingly peralkaline compositions: pantelleritc trachyte first and then, after &gt;65 % crystallization, to pantellerite. This also results in the formation of a syenitic cumulate. Later intrusion of new mafic melt into the cumulate initiates partial melting, which produces comenditic trachyte melts characterized by low concentrations of incompatible trace elements (Rb, Zr, Nb, Th), high concentrations of Ba and Sr, and strong positive Eu anomalies. Entrainment of trachytic alkali feldspars into these melts as antecrysts further enhances these characteristics in whole-rock compositions. The origin of compositional zoning in the Green Tuff can be attributed to fractional crystallization from metaluminous trachyte within the lower pantelleritic portion and to partial melting of the syenitic cumulate for the upper comenditic trachyte portion.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126288"},"PeriodicalIF":2.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mixed fluid processes in FeMn dendrite formation and associated carbon and nickel isotope fractionation","authors":"Anna Neubeck ,&nbsp;Piotr Szymczak ,&nbsp;Vyllinniskii Cameron ,&nbsp;Daniel Buczko ,&nbsp;Magnus Ivarsson","doi":"10.1016/j.chemer.2025.126303","DOIUrl":"10.1016/j.chemer.2025.126303","url":null,"abstract":"<div><div>Dendritic iron- and/or manganese-rich microstructures, often referred to as “microstromatolites,” are commonly observed in carbonate veins in the deep subsurface. However, the mechanisms responsible for their formation, particularly the role of microbial processes, remain incompletely understood. One hypothesis suggests that Fe- and Mn-enriched fluids, sourced from submarine hydrothermal vents and circulating through mafic or ultramafic rocks, lead to the precipitation of manganese dendrites within open fractures. Microbial activity has been proposed as a contributing factor, particularly due to its ability to catalyze Mn²⁺ oxidation to Mn⁴⁺ at rates significantly faster than abiotic processes under ambient conditions. Such microbial mediation often results in the formation of poorly crystalline Mn oxide phases, which are commonly associated with biologically mediated oxidation. These disordered Mn oxides, frequently observed in natural settings, suggest a microbial contribution to mineral precipitation, particularly in environments where redox gradients and fluid-rock interactions are prominent. Because manganese oxides are an important sink for Ni in marine systems, stable Ni isotope analyses may offer valuable insights into their formation. Biological activity in laboratory systems is known to fractionate Ni isotopes, producing negative δ⁶⁰Ni values, while abiotic interactions with Mn oxides can result in a range of isotopic signatures. In this study, we show that manganese-rich dendrites likely formed through the interplay between organic matter, oxidizing fluids and viscous serpentine muds, resulting in the fractionation of both carbon and nickel isotopes. The moderately negative δ¹³C and δ⁶⁰Ni values, together with the presence of organic matter, suggest a mixed formation pathway involving both abiotic mineral precipitation and biologically mediated processes. One plausible mechanism involves the nucleation of Mn oxides on nanoparticulate “seeds,” which could include both abiotic particles, organic matter, microbial cells and their metabolic byproducts. Understanding the formation of Fe<img>Mn dendrites is key to interpreting the biogeochemical cycling of essential elements like iron, manganese, and nickel. Due to its redox flexibility, Mn forms highly reactive oxides that effectively scavenge trace metals such as Ni, Co, Fe, and Cu, facilitating their removal from seawater and incorporation into marine minerals. Our findings underscore the complexity of Fe<img>Mn oxide formation and point to the combined influence of abiotic fluid dynamics and microbial processes. This improves our ability to interpret geochemical signatures in both modern and ancient environments and enhances the utility of stable isotope systems in reconstructing past ocean conditions and elemental cycling.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126303"},"PeriodicalIF":2.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biotite geochemical fingerprints deciphering magma evolution and compositional diversity of the concentric Zhongchuan Batholith, West Qinling, China","authors":"Zhihui Wang ,&nbsp;Fan Yang ,&nbsp;Feifan Xu ,&nbsp;Leon Bagas ,&nbsp;Cun Zhang ,&nbsp;Zengsheng Li ,&nbsp;Weidong Ren","doi":"10.1016/j.chemer.2025.126315","DOIUrl":"10.1016/j.chemer.2025.126315","url":null,"abstract":"<div><div>Compositional diversity is a common feature of plutons and a frequent topic in earth science publications. The Zhongchuan Batholith, a composite body in the West Qinling Orogen of central China, provides an important example for understanding compositional variations and the genesis of different granitic phases. The batholith consists of three annular rings (medium-coarse grained porphyritic biotite granite, medium grained phenocryst-bearing biotite granite, and medium-fine grained biotite granite) from the outer to inner rings. Biotite is the most common ferromagnesian mineral in diverse granitic phases of the batholith and can serve as key indicators for the geochemical characteristics of the granites and their compositional variations. In this study, we present major and trace element geochemistry of biotite to constrain the physico-chemical conditions and petrogenesis of the various granitic phases in the batholith. Microstructural and alteration studies of biotite from the different granitic phases reveal features consistent with magmatic biotite. The major elements of the biotites indicate crystallisation temperatures of approximately 778 °C, 755 °C, and 726 °C for the outer, intermediate, and inner rings, respectively. These temperatures correspond to pressures of ~210 MPa (7.5 km), 390 MPa (14 km), and 440 MPa (16 km). The observed changes in crystallisation temperatures and pressures are consistent with the evolution of multi-stage and differentiated magma. The oxygen fugacity of biotite varies from −16 to −12, indicating a high magma oxygen fugacity. Major and trace elements of biotite further attest that the batholith is classified as I-type granite, derived from crust-mantle mixing, with a greater contribution of mantle-derived materials in the outer ring. The compositional diversity of the batholith is attributed to high-degree magma mixing without fractional crystallisation during magma evolution.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126315"},"PeriodicalIF":2.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Сomposition, evolution and age of Nb-REE mineralization in carbonatite complexes in the Ural Fold Belt: New insight into metallogenesis","authors":"I.L. Nedosekova ,&nbsp;B.V. Belyatsky ,&nbsp;S.V. Pribavkin ,&nbsp;V.А. Bulatov","doi":"10.1016/j.chemer.2025.126246","DOIUrl":"10.1016/j.chemer.2025.126246","url":null,"abstract":"&lt;div&gt;&lt;div&gt;&lt;span&gt;&lt;span&gt;The Ilmeno-Vishnevogorsk (IVC) and Buldym carbonatite complexes of the Southern Urals are deformed linear-type carbonatite complexes that underwent &lt;/span&gt;tectonic evolution&lt;span&gt;&lt;span&gt;&lt;span&gt; as a result of accretion-collision processes and the Hercynian collision orogeny. The deposits of niobium and &lt;/span&gt;rare earth elements are associated with the Ural carbonatite complexes. Nb-REE ore mineralization is represented by the pyrochlore supergroup minerals, aeschynite and &lt;/span&gt;monazite&lt;span&gt;. Their compositional evolution and connection with various phases of alkaline magmatism, pegmatite and carbonatite formation, and late postmagmatic (carbothermal) processes were studied. To determine the age and duration of the ore-forming stages, U&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;img&gt;Pb dating of minerals pyrochlore supergroup phases and monazite was carried out. The pyrochlore-group minerals of the Ural carbonatite complexes are represented by calciopyrochlore, rarely natropyrochlore, and kenopyrochlore. Pyrochlore &lt;em&gt;I&lt;/em&gt;, rich in U-(Ta), crystallizes in the earliest magmatic phases of the IVC, in the miaskites and carbonatites I of the Central Alkaline Band. In contrast, Ta-(U)-bearing pyrochlore &lt;em&gt;II&lt;/em&gt;&lt;span&gt; is formed in the later magmatic phases, in the taxitic miaskites and miaskite-pegmatites, and is present in explosive carbonatite breccias and carbonatites II of the Vishnevogorsk massif. Both varieties of pyrochlore have magmatic characteristics – oscillatory zoning, absence of vacancies in the A-site, and low Nb/Ta &lt;80. Pyrochlore &lt;/span&gt;&lt;em&gt;III&lt;/em&gt; and Sr-REE-containing pyrochlore &lt;em&gt;IV&lt;/em&gt;&lt;span&gt; – with high Nb/Ta &gt;300 and fluorine (4–5 wt%), are formed from fluid-saturated F-containing carbonate systems&lt;span&gt; in carbonatites II of the IVC miaskite intrusions and fenite halos, as well as in carbonatites III and fenites of the Buldym complex. REE minerals – aeschynite-(Ce) and monazite-(Ce) formed in the carbothermalites of the Buldym complex and in fenite halos of miaskite massifs. The morphological features and evolution of the pyrochlore composition indicate the polygenic nature of the ore process, the late low-temperature stage of which is associated not only with Nb but also with REE mineralization (aeschynite, monazite).&lt;/span&gt;&lt;/span&gt;&lt;/div&gt;&lt;div&gt;&lt;span&gt;The results of U-Pb-dating of the pyrochlore- and monazite-group minerals make it possible to distinguish two stages of ore formation in the studied carbonatite complexes of the Southern Urals. The early stage is recorded by U-(Ta)-rich pyrochlore in carbonatites I, the Potanino deposit (378 ± 5 Ma), and can be correlated with the primary crystallization of the IVС alkaline rocks and carbonatites at the rifting stage (D&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;) of the forming continental margins. Whereas, the late stage is dated at ∼255–230 Ma yielded for pyrochlores &lt;/span&gt;&lt;em&gt;II-IV&lt;/em&gt; of the Vishnevogorsk deposit – in taxitic miaskites, syenite- and miaskite-pegmatites, as well a","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126246"},"PeriodicalIF":2.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectroscopic signatures for expeditious monitoring of contamination risks at abandoned coal mine sites","authors":"Jelena Milinovic ,&nbsp;Patrícia Santos ,&nbsp;Jorge Espinha Marques ,&nbsp;Deolinda Flores ,&nbsp;Aurora Futuro ,&nbsp;Carlos M. Pereira ,&nbsp;Manuel Azenha","doi":"10.1016/j.chemer.2025.126292","DOIUrl":"10.1016/j.chemer.2025.126292","url":null,"abstract":"<div><div>Soil acts as a natural ‘filter’, playing a crucial role in the transfer of geogenic and anthropogenic pollutants from abandoned coal mine sites to surrounding water bodies. Key indicators of soil contamination, such as pH, electrical conductivity (EC), and organic matter (OM), expressed as loss-on-ignition (LOI), can signal contamination risks when they deviate from optimal ranges. To enable sustainable risk assessment through monitoring of pH, EC, and LOI, streamlined spectroscopic techniques Fourier transform infrared (FTIR), near-infrared (NIR), Raman, and X-ray fluorescence (XRF) were applied in combination with multivariate analysis (MVA), to soil samples from two abandoned coal mines in NW Portugal. Partial least squares (PLS) regression models demonstrated that XRF spectroscopic data provided the most accurate assessment of soil pH, EC, and LOI at the local scale (R² = 0.92–0.99). The most significant spectroscopic signatures, identified through weighted regression coefficients (B_w), enabled robust predictions of these key soil parameters. These findings highlight that these geochemical variables outperform molecular spectroscopy techniques for efficient and environmentally relevant risk monitoring of contamination in abandoned coal mine sites.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126292"},"PeriodicalIF":2.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced analysis of hydrothermal alteration and mineral prospecting through integration of ASTER and aeroradiometric data: A case study from the Ouarzazate region, Morocco","authors":"Ilham El Hakimi,&nbsp;Lahsen Achkouch,&nbsp;Younesse El Cheikh,&nbsp;Mohammad Taadid,&nbsp;Houda Bourouda,&nbsp;Ahmed Rachid,&nbsp;Ahmed Attou","doi":"10.1016/j.chemer.2025.126296","DOIUrl":"10.1016/j.chemer.2025.126296","url":null,"abstract":"<div><div>The study area, situated in the western segment of the Saghro Massif within the Anti-Atlas belt, is characterized by mineralized deposits, intricate lithological formations, and distinctive tectonic features. This research integrates ASTER imagery analysis with gamma-ray spectrometry data to map alteration zones and examine the geochemical and mineralogical processes that influence radioactive element distribution. Specific analytical techniques are applied to investigate relationships among argillic, phyllic, propylitic alterations, iron oxides, and regions with elevated concentrations of radiometric elements. Gamma-ray spectrometry data, including mono-elemental maps of radiometric components (potassium in %, equivalent uranium in ppm, and equivalent thorium in ppm), are analyzed alongside interpreted ASTER images to identify potential mineralization zones. Ratios of K/eU and K/eTh, along with the F parameter, are processed within a fuzzy model framework, which combines these datasets into a comprehensive mineral prospectivity map that serves as a tool for guiding exploration. This analysis identifies four hydrothermal alteration zones as highly promising for mineral exploration, suggesting a likely association between magmatic processes and spatially correlated hydrothermal alteration, thereby supporting further detailed exploration initiatives.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 3","pages":"Article 126296"},"PeriodicalIF":2.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}