Chemie Der Erde-Geochemistry最新文献

{"title":"Petrogenesis of Paleoproterozoic mafic magmatic rocks from Garhwal Lesser Himalayan Sequence: Implications for Precambrian crustal recycling and geodynamic evolution of proto-northern Indian continental margin","authors":"Ashutosh Pandey ,&nbsp;H.K. Sachan ,&nbsp;Digvijay K. Dubey","doi":"10.1016/j.chemer.2026.126387","DOIUrl":"10.1016/j.chemer.2026.126387","url":null,"abstract":"<div><div>The Precambrian geodynamic evolution of the proto-northern Indian continental margin remains elusive. Mafic magmatic rocks from the Lesser Himalayan Sequence, representing the northern extremity of the Indian Shield, provide key constraints on this evolution. This study presents new mineralogical and whole-rock geochemical data from mafic rocks in the Rudraprayag-Karnaprayag sector of the Garhwal Lesser Himalayan region, aiming to elucidate their genesis and geodynamic significance. The whole-rock geochemistry of the studied rocks exhibits enrichment in large-ion lithophile elements and depletion in high-field strength elements, with elevated Ba/Nb, Th/Yb, and La/Sm ratios, indicative of subduction-related metasomatism of the mantle source. The most primitive samples (with MgO &gt; 7.5 wt%) exhibit major element systematics consistent with melts derived from a pyroxene-dominated mantle source, possibly produced by interaction between peridotite and siliceous melt. Estimated melting temperatures (1198–1385 °C) exclude the possibility of involvement of anomalously hot mantle plumes in the origin of these rocks and point towards a passive continental rifting setting. These observations suggest that the Paleoproterozoic mafic magmatic rocks of the Lesser Himalayan Sequence possibly originated in a continental back-arc extensional setting linked to an Andean-type active continental margin along the proto-northern Indian cratonic block. Our results support the evidence for an Andean-type active continental margin along the proto-northern Indian continental margin during the assembly of the Columbia supercontinent in the Paleoproterozoic.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126387"},"PeriodicalIF":2.9,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977864","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":"Compositional zoning, crystal chemistry and metamorphic growth of monazite in the Greater Himalayan Sequence, Dhauliganga Valley, Garhwal Himalaya","authors":"Chandni Chaurasia ,&nbsp;Satyajeet S. Thakur ,&nbsp;Suresh C. Patel ,&nbsp;Nainika Gour ,&nbsp;Janisar M. Sheikh","doi":"10.1016/j.chemer.2025.126384","DOIUrl":"10.1016/j.chemer.2025.126384","url":null,"abstract":"<div><div>X-ray elemental mapping and quantitative analysis of monazite grains contained in metapelites from the Greater Himalayan Sequence (crystalline core of the Himalaya) of the Dhauliganga Valley, Garhwal Himalaya were performed by electron probe micro-analyser to evaluate the zoning patterns. The rocks, from which monazites have been studied, include those with peak metamorphism (650–715 °C and 8.0–9.9 kbar) under subsolidus conditions and also those showing evidences of partial melting (&lt;800 °C and 10.5 kbar). All the monazite analyses taken together show that Light Rare Earth Elements (LREEs) constitute 80–89 % of the total cation proportion (exclusive of P) and Heavy Rare Earth Elements (HREEs) 1–4 %, while other elements make 9–18 %. Zoning patterns vary from core–rim to patchy and irregular types. The rim is invariably Y-rich compared to the core. Compositional variability of monazites can be explained mostly by the brabantite substitution: 2REE³⁺ = (Th,U)⁴⁺ + Ca²⁺. Y shows negative correlation with LREE and positive correlation with HREE. The U-Th-Pb in situ analyses of one of the samples (HH52) suggests that the monazite grew at 26.28 ± 0.19 Ma. Likely metamorphic reactions for the growth of Y-poor monazite core and its resorption followed by overgrowth of Y-rich rim during progressive metamorphism have been explored. Phase equilibria considerations indicate that resorption and regrowth of monazite can occur in both subsolidus and suprasolidus regimes. The P–T path for the development of resorption–regrowth texture of monazite is inferred to be isothermal decompression in the case of subsolidus regime, and isobaric cooling to retrograde decompression in the case of suprasolidus conditions.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126384"},"PeriodicalIF":2.9,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925916","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":"Degassing in middle-crust magma chamber: Evidence from the texture and chemistry of the zonal clinopyroxene from the high magnesium basalt in Ganzhou Basin, Jiangxi, South China","authors":"Lin Jia ,&nbsp;Guolin Guo ,&nbsp;Yan Zhao ,&nbsp;Zhaobin Yan ,&nbsp;Jianhua Wu ,&nbsp;Wenya Yan ,&nbsp;Tingting Zou","doi":"10.1016/j.chemer.2026.126386","DOIUrl":"10.1016/j.chemer.2026.126386","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Magmatic degassing is a key process during the ascent and evolution of basaltic magmas, providing critical insights into deep crust environments and geodynamics. Clinopyroxene, a ubiquitous ferromagnesian mineral in basaltic systems, exhibits compositional sensitivity to magmatic physicochemical conditions (e.g., temperature, pressure, H₂O content, oxygen fugacity) and thus serves as a valuable petrogenetic archive. This study investigates degassing events recorded by compositionally-zoned clinopyroxene phenocrysts in Late Cretaceous high-Mg basalts from the Ganzhou Basin, Jiangxi Province, China. Previous Sr-Nd-Pb-O isotope results indicated that these basalts were derived from an enriched mantle source without significant crustal contamination. Clinopyroxene grains predominantly exhibit distinct core-mantle-rim zoning. Equilibrium melt compositions, simulated based on clinopyroxene core, mantle, and rim compositions, yield high MgO contents (14.01–15.00 wt%), consistent with the high-Mg bulk-rock composition of Ganzhou basalts, despite minor discrepancies in some trace elements. Systematic major- and trace-element variations are observed across the zonal domains: Al₂O₃ contents progressively decrease from core to rim, while Fe, Ti, and trace elements increase significantly. Cores and mantles display characteristic negative Pb, Nd, and Zr anomalies. The decreasing Al₂O₃ trend reflects reduction tetrahedral Al&lt;sup&gt;3+&lt;/sup&gt; occupancy in the clinopyroxene lattice with declining temperature and pressure during magmatic evolution, whereas the negative anomalies are attributed to early-stage magma evolution, geochemical imprints from the enriched mantle source, and ilmenite crystallization. Clinopyroxene thermobarometry reveals significant differences among zones: cores and mantles crystallized under relatively high temperatures, pressures, and melt water contents conditions, whereas rims and matrix clinopyroxenes formed under distinctly lower temperature, pressure, and melt water content. The sharp decrease in melt water content coupled with relatively stable Fe&lt;sup&gt;3+&lt;/sup&gt;/ΣFe ratio from core to mantle, indicate a degassing/dehydration process in the middle-crust. The observed trends-sharp decrease in temperature, pressure, and Fe&lt;sup&gt;3+&lt;/sup&gt;/ΣFe from mantle to rim, alongside a more gradual decline in melt water content, suggest magma eruption following degassing from a middle-crustal chamber. The contrasts between clinopyroxene phenocryst rims and matrix grains, characterized by further decreases in temperature and pressure but slight increases in H₂O content and Fe&lt;sup&gt;3+&lt;/sup&gt;/ΣFe ratio, are interpreted as reflecting eruption into an oxidizing and hydrating atmospheric environment. Combine the regional tectonic setting, the formation of the Ganzhou Basin Late Cretaceous high-Mg basalts is related to an intra-continental extensional environment induced by westward subduction of the paleo-Pacific Plate beneath the Eurasian continent, wi","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126386"},"PeriodicalIF":2.9,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977865","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":"Major element zonation following rapid heating of homogeneous glass in superliquidus experiments","authors":"Siobhan E.L. Kingham ,&nbsp;Matthew Varnam ,&nbsp;Lee M. Saper ,&nbsp;Geoffrey D. Bromiley","doi":"10.1016/j.chemer.2025.126383","DOIUrl":"10.1016/j.chemer.2025.126383","url":null,"abstract":"<div><div>High-temperature melting experiments in gas-mixing furnaces are used to simulate magmatic processes and provide insight into melt properties at controlled conditions. These experiments assume that rapid melting results in formation of homogeneous molten samples, especially when glassed starting materials are used. As part of an investigation of evaporative loss of moderately volatile elements (MVE) from lunar magma, we performed short-duration, superliquidus experiments using homogeneous glass starting materials. Powdered glass pellets and glass fragments were suspended on Pt wire loops, and rapidly inserted into the hotspot of a 1-atm vertical gas-mixing furnace at 1350 °C and log <em>f</em>O₂ = IW to IW +2 (oxygen fugacity at, or 2 log units above, the Fe-FeO buffer). Samples were held within the furnace for 5–60 min before being drop-quenched into water. Scanning electron microscopy and electron probe microanalysis of sectioned run products evidence progressive MVE loss from samples, but with additional, unexpected, redistribution of refractory elements (SiO₂, TiO₂, MgO, FeO, Al₂O₃, CaO). Refractory element zonation reflects early heating processes, and is progressively eradicated during prolonged heating via diffusion. Zonation in shorter duration experiments also reveals variable, and sometimes chaotic, disruption of samples during quenching. We propose that refractive element zonation arises due to phase separation during heating, driven by partial devitrification of the interiors of glassy samples. Our results demonstrate that element redistribution during melting, and physical disruption of samples induced by quenching, can significantly affect chemical homogeneity. These effects should be considered when designing and interpreting data from short-duration high-temperature experiments.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126383"},"PeriodicalIF":2.9,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884250","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":"Pyrite chemistry patterns in gold-bearing metaconglomerates of the Jacobina Group, São Francisco Craton, Northeastern Brazil: Multivariate mineral chemistry insights and geological implications for gold exploration","authors":"Guilherme Ferreira da Silva ,&nbsp;Adalene Moreira Silva ,&nbsp;Catarina Labouré Bemfica Toledo ,&nbsp;Guilherme dos Santos Teles ,&nbsp;Farid Chemale Junior ,&nbsp;Evandro Luiz Klein ,&nbsp;Artur Areal Braga","doi":"10.1016/j.chemer.2025.126382","DOIUrl":"10.1016/j.chemer.2025.126382","url":null,"abstract":"<div><div>The gold-bearing metaconglomerates of the Jacobina Group exhibit complex mineralogical and geochemical features that are significant for gold exploration in the northern São Francisco Craton. A comprehensive analysis of pyrite chemistry patterns within the Jacobina Group was carried out using multivariate mineral chemistry techniques and geological constraints to elucidate their significance for gold exploration. Distinct pyrite types, distinguished by morphology, texture, and stratigraphic position, were identified through Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) analysis. The results reveal a clear positive correlation between trace elements within detrital and epigenetic pyrite populations, providing insights into their origin and evolution. Notably, the presence of accessory minerals such as sphalerite, chalcopyrite, and pyrrhotite serve as key indicators of late-stage hydrothermal alteration and potential gold mineralization. The dimensionality reduction techniques, including Uniform Manifold Approximation and Projection (UMAP), indicate a spatial distribution of pyrite populations across different stratigraphic units. Moreover, agglomerative clustering analysis indicates that both geological context and mineral chemistry are important for delineating exploration targets. Our findings demonstrate that integrating multivariate mineral chemistry analysis with geological constraints can enhance gold exploration strategies. This study provides valuable insights into the complex relationship between pyrite chemistry, geological processes, and gold mineralization within the Jacobina Group, advancing our understanding of auriferous metaconglomerate deposits.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126382"},"PeriodicalIF":2.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884252","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":"Mineralogical, geochemical, spectroscopic, and color-making elements investigation of agate and chalcedony mineralization; case study: Kasrab district, east Iran","authors":"Mohammadreza Hosseinzadeh ,&nbsp;Ali Asadi ,&nbsp;Vartan Simmonds ,&nbsp;Matthew I. Leybourne","doi":"10.1016/j.chemer.2025.126381","DOIUrl":"10.1016/j.chemer.2025.126381","url":null,"abstract":"<div><div>The agate and chalcedony mineralization in the Kasrab area displays a wide spectrum of colors, including black, purple, green, blue, lily (lavender), moss, red, lemon, and white, reflecting variations in trace elements and formation conditions. These minerals occur mainly in veins and veinlets cutting through carbonate rocks, as well as in open-space fillings within fresh and hydrothermally altered andesites. Moganite, a quartz polymorph, occurs both in vesicles and as microcrystalline overgrowths, indicating its role in the complex silica precipitation processes. Altered volcanic rocks show elevated concentrations of Al₂O₃, Fe₂O₃, Na₂O, K₂O, P₂O₅, and TiO₂, whereas fresh host rocks are richer in CaO and MgO, reflecting element mobilization during acidic hydrothermal alteration. Geochemical analyses reveal enrichment of LILEs (relative to primitive mantle-normalized values) and LREEs (relative to chondrite-normalized REE values) in both agates samples and host rocks, with agates showing slight LREE depletion, HREE enrichment (except Tm), and anomalies of Nb (negative) and Cs, U, Pb (positive), but negligible Eu anomaly. Petrographic study identified two main fluid inclusion types—vapor-rich (VL) and liquid-rich (LV)—with microthermometry indicating salinities up to 4.65 wt% NaCl equivalent and homogenization temperatures of 97–124 °C, consistent with low-salinity, low-temperature hydrothermal formation. Fluorescence spectroscopy revealed emission peaks of quartz, Cr³⁺, and Ca-bearing minerals (aragonite, calcite, diopside), while FT-IR confirmed hydroxyl groups, molecular water, and hydrated silica phases (opal-A, opal-C, opal-T). UV–Vis spectroscopy identified Fe³⁺ and Ni²⁺ transitions associated with hematite and goethite, contributing to coloration. Physical measurements show translucent agates have higher refractive indices and specific gravity than transparent ones, reflecting subtle differences in microstructure and impurity content.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126381"},"PeriodicalIF":2.9,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884251","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":"Petrogenesis of an A2-type intrusion associated with the late-post-collisional calc-alkaline Variscan granites from central-northern Portugal (Central Iberian Zone)","authors":"Luís Portela,&nbsp;Maria Rosário Azevedo,&nbsp;Jorge Medina,&nbsp;Beatriz Valle Aguado","doi":"10.1016/j.chemer.2025.126376","DOIUrl":"10.1016/j.chemer.2025.126376","url":null,"abstract":"<div><div>The Lusinde fine-grained biotite granite is a small pluton intruded into the metamorphic basement of the Central Iberian Zone during the waning stages of the Variscan Orogeny. LA-ICP-MS zircon U<img>Pb ages constrain pluton emplacement to ca. 297–295 Ma. Mineralogical and geochemical data reveals that the intrusion corresponds to a strongly ferroan, peraluminous, reduced A₂-type granite (∆FMQ = −3.4 to −1.7, zircon oxybarometry), characterised by a narrow compositional range (SiO₂ = 67.7–68.8 wt%), elevated FeO_T/FeO_T + MgO (0.90–0.92) and 10,000 × Ga/Al (3.1–3.4) ratios, high REE, LILE and HFSE contents and strong depletions in Ba, Sr, Nb, P, Eu and Ti. Decoupling between “mantle-like” Nd and zircon Hf (εNd_i = −0.40 to +0.58; T_DM2 = 0.81–0.95 Ga; zircon εHf_i = −0.41 to +3.01; T_DM2-Zrn = 1.08–1.30 Ga) and more “crust-like” Sr (⁸⁷Sr/⁸⁶Sr_i = 0.7097–0.7100) isotopic signatures suggests derivation from small degrees of partial melting of old juvenile mafic/intermediate rocks interlayered in the lower crust, with minor input from more evolved crustal sources. The only studied ferrodioritic enclave shares the A₂-type affinity of the host granite and seems to have derived from a mixed source (enriched subcontinental lithospheric mantle and juvenile mafic crust), before injection into the silicic magma chamber. We propose that the generation of the Lusinde A-type granite magma and enclosed enclave occurred in a deep hot zone located at the mantle-lower crust interface, at about 7–10 kb and 850–950 °C, in an extensional post-collisional setting.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126376"},"PeriodicalIF":2.9,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840874","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":"Compositional balance analysis for geochemical prospectivity mapping in Nenjiang–Heihe region, China","authors":"Lidong Zhang ,&nbsp;Yue Liu ,&nbsp;Kewei Zhang ,&nbsp;Ziqiang Zha ,&nbsp;Jianeng Wu ,&nbsp;Wenjun Xuan ,&nbsp;Huiyuan Zhang","doi":"10.1016/j.chemer.2025.126375","DOIUrl":"10.1016/j.chemer.2025.126375","url":null,"abstract":"<div><div>The Nenjiang–Heihe district, on the eastern margin of the Central Asian Orogenic Belt, hosts porphyry Cu<img>Mo and epithermal Au systems emplaced through multiple tectonomagmatic episodes. To extract process–diagnostic signals from regional geochemistry and convert them into practical exploration targets, we applied compositional balance analysis (CoBA) and the concentration–area (C–A) fractal model to stream–sediment geochemical data collected from the Nenjiang–Heihe region, China. Compositional hierarchical clustering and a suite of data– and knowledge–driven balances identify three complementary geochemical patterns: (i) Fe–oxide–rich intermediate–mafic domains that define broad NNE–NE corridors coincident with volcanic belts and major faults; (ii) porphyry/base–metal chalcophile behavior (e.g., <em>b01</em>, <em>b02</em>, <em>b03</em>, <em>b08, b7</em>, <em>b26</em>, and <em>b31</em>) that captures Cu anomalies along permeable structures; and (iii) felsic–HFSE/LILE fertility and volatile–rich epithermal overprints, highlighted by <em>b05, b06</em>, <em>b07, b15</em>, and <em>b1</em>6, localized over or adjacent to intermediate–felsic intrusions. C–A breakpoints provide objective thresholds that delineate statistically significant targets. Highest–priority prospects occur where <em>b01–b02</em> highs overlap at fault intersections and locally coincide with <em>b06</em> anomalies. The results demonstrate that CoBA, coupled with C–A segmentation, offers a low–cost, and interpretable framework for prospectivity mapping in forest–swamp terrain, mitigating closure effects and enhancing weak but geologically meaningful signals for decision–making.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126375"},"PeriodicalIF":2.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791277","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":"Assessing the evidence for active volcanism on Venus: current limitations and prospects for future investigations","authors":"Justin Filiberto ,&nbsp;Mikhail Yu. Zolotov ,&nbsp;Erika Kohler ,&nbsp;Piero D'Incecco ,&nbsp;Dmitry A. Gorinov ,&nbsp;Sriram S. Bhiravarasu ,&nbsp;Matthew B. Weller ,&nbsp;Jeremy F. Brossier ,&nbsp;Iván López ,&nbsp;Philippa J. Mason ,&nbsp;Jemila A. Edmond ,&nbsp;Nicola Mari ,&nbsp;Goro Komatsu ,&nbsp;Gaetano Di Achille ,&nbsp;James B. Garvin","doi":"10.1016/j.chemer.2025.126316","DOIUrl":"10.1016/j.chemer.2025.126316","url":null,"abstract":"<div><div>One of the biggest unknowns about Venus is how volcanically active it is today. Venus has a similar size and density to Earth, suggesting it may have a comparable composition, and therefore it is expected to be volcanically active; however, exploring Venus and confirming current volcanic activity is difficult because of the thick omnipresent optically opaque clouds that hamper traditional observations of the lower atmosphere and surface. Further, surface conditions make long-lived missions challenging. Despite the difficulty, there have been tantalizing hints of currently active or very recent volcanism. Here, we review what is known about active volcanism, point out gaps in knowledge to be addressed, and highlight techniques and approaches that need to be developed before the new decade of Venus exploration. It is crucial to constrain the activity and rate of volcanism today and through time to begin to understand the geodynamic state of the planet.</div><div>We find that the combination of all evidence strongly indicates that Venus is volcanically active today. The best evidence for active volcanism comes from combining data sets and approaches – specifically at Idunn Mons, Maat Mons, and Aramaiti Corona – in contrast to those from a single study or data set alone. Considering the evidence for activity, observations do not favor so-called “catastrophic” models of resurfacing, instead they are better represented by ongoing regional scale events. To reliably detect and characterize active or recent effusive basaltic volcanism new missions must collect high-resolution imaging, repeat observations, radar polarimetry, evidence of outgassing, and high-resolution topographical data that provide insights into surface changes over time. The ability to capture and interpret these data is vital for understanding Venus's geological activity, particularly in regions where volcanic processes are suspected to be ongoing.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126316"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789738","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":"Petrogenesis of the Niancaowan mafic-ultramafic intrusion: Decoding magmatic evolution in the cuNi Metallogenic Province of the Bayan obo rift zone","authors":"Linna LI ,&nbsp;Jiangang JIAO ,&nbsp;Yunfei MA","doi":"10.1016/j.chemer.2025.126359","DOIUrl":"10.1016/j.chemer.2025.126359","url":null,"abstract":"<div><div>The Niancaowan mafic-ultramafic intrusion is located within the Bayan Obo Rift Zone of central Inner Mongolia. Systematic genetic investigations were conducted in this study to clarify the genetic relationship between the Niancaowan mafic-ultramafic intrusion and known Cu<img>Ni deposits within the rift zone, as well as to assess the comparability of their mineralization potential. Through integrated petrographic observations, high-precision geochronological dating, whole-rock geochemical analyses, and zircon Hf isotope tracing, the research specifically focused on elucidating the magmatic source characteristics, rock-forming timing, and magmatic evolutionary processes of the intrusion. The Niancaowan mafic-ultramafic intrusion is predominantly composed of hornblende gabbro and gabbro-diabase. LA-ICP-MS zircon U<img>Pb dating reveals that the hornblende gabbro crystallized during the Early Permian (273.2 ± 3.5 Ma), which demonstrates temporal synchronicity with the emplacement ages of other mafic-ultramafic intrusions within the central-western Inner Mongolia rift system. Geochemical tracers further disclose significant zircon Hf isotopic heterogeneity, indicating that the parental magma was derived from partial melting of a lithospheric mantle source and underwent contamination by lower crustal materials during its ascent. Comparative analysis indicates that the zircon Hf isotopic compositions of the Niancaowan intrusion (ε_Hf(t) = −17.0 to +1.4) are similar to those of typical regional intrusions such as the Wulantaolegai and Huanghuatan intrusions, revealing that crustal contamination was prevalent during the emplacement of mafic-ultramafic magmatic systems within the Bayan Obo Rift Zone. The incorporation of such crust-derived components may be controlled by the melting or assimilation processes of ancient basement rocks in the extensional setting of the rift zone. The petrological characteristics and quantitative modeling results indicate that the Niancaowan intrusion experienced relatively weak crustal contamination (4 %–8 %). If sulfide mineralization were to occur in this intrusion, it would primarily depend on deep-seated magmatic differentiation. Comparative studies between the Niancaowan intrusion and other intrusive bodies within the Bayan Obo Rift Zone reveal that the mineral exploration potential of mafic-ultramafic intrusions in the Bayan Obo Rift Zone should not be overlooked. Particular attention should be given to highly contaminated mafic-ultramafic intrusion clusters within the rift zone and multi-stage tectonic-magmatic convergence nodes.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126359"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617852","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}