Chemie Der Erde-Geochemistry最新文献

{"title":"Fluid evolution and ore genesis of the Amensif ZnCu (Pb-Ag-Au) distal skarn deposit (western High Atlas, Morocco): Constraints from fluid inclusions, crush-leach analysis, REY geochemistry, and Pb isotopes","authors":"Larbi Rddad ,&nbsp;Abdessamad Jinari ,&nbsp;Benjamin F. Walter ,&nbsp;Mohsin Raza ,&nbsp;Rachid Benaouda ,&nbsp;El Mostafa Mouguina","doi":"10.1016/j.chemer.2025.126353","DOIUrl":"10.1016/j.chemer.2025.126353","url":null,"abstract":"<div><div>This study investigates the genesis of hydrothermal mineralization at the Amensif Zn<img>Cu (Pb-Ag-Au) ore deposit, hosted within Cambrian carbonates. Three stages of mineralization are identified, beginning with a pre-ore phase characterized by early pyrite precipitation from high-temperature (395–426 °C), highly saline (53.0–59.3 wt% NaCl + CaCl₂) magmatic-hydrothermal fluids under reducing conditions, consistent with a negative Eu anomaly in the Rare Earth Elements and Yttrium (REY) data. Stage I is marked by homogenization temperatures (340–395 °C) and moderate salinities (23.3–24.4 wt% NaCl + CaCl₂), indicating mixing of magmatic and cooler meteoric fluids. Stage II involves cooler (225–260 °C), less saline (17.6–20.4 wt% NaCl + CaCl₂) fluids, indicating dilution with meteoric waters. Principal Component Analysis (PCA) of crush-leach data indicates the involvement of both brine and vapor phases in metal transport and mineralization.</div><div>Lead isotopic and REY data point to a common metal source derived from both mantle and crustal reservoirs, with isotopic uniformity indicating thorough Pb mixing. This aligns with a conceptual metallogenic model in which deep-seated ENE-WSW faults enable magma ascent during post-collision collapse, whereas reactivated NE-SW and NW-SE faults provide pathways for metal-rich magmatic-hydrothermal fluids exsolved from a Permian granitic magma. Fluid mixing and fluid-rock interaction processes facilitated ore deposition in the Cambrian carbonates. These findings provide new insights into the structural and geochemical factors controlling ore genesis at the Amensif deposit and similar magmatic-hydrothermal skarn systems associated with the Hercynian/Variscan orogeny.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126353"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617954","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":"Mineral composition, trace element geochemistry and metallogenic processes of the early Cambrian black rock series-hosted Xiajiadian gold‑vanadium deposit, southern Qinling, China","authors":"Bei Li,&nbsp;Laimin Zhu,&nbsp;Xiao Xiong,&nbsp;Lele Ding,&nbsp;Yuanbo Ma,&nbsp;Shenghao Li,&nbsp;Yang Jiang","doi":"10.1016/j.chemer.2025.126362","DOIUrl":"10.1016/j.chemer.2025.126362","url":null,"abstract":"<div><div>Black rock series are significant in economic geology as they harbor abunbant mineral resources and are often spatially associated with several types of ore deposits. The Xiajiadian deposit is a large-scale, unique Au<img>V co-product system within these series, yet its mineralogy and detailed metallogenic mechanisms remain poorly constrained. This study employs an integrated approach, including scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe micro-analysis (EMPA), and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), to systematically determine the mineral composition, trace element geochemistry, and occurrence modes of Au and V.</div><div>The black rock series exhibit a complex mineral assemblage, comprising not only quartz, feldspar, carbonates, and clays but also key ore-related minerals such as barite, roscoelite, anatase, and goethite. Geochemical data reveal significant enrichment of Au, V, Ba, P, and Mo,compared to the upper continental crust. Furthermore, we propose a two-stage metallogenic model: first, a sedimentary/diagenesis and metallogenic stage during which hydrothermal-seawater-microbial interactions led to V enrichment to industrial grades and pre-concentration of Au; subsequently, a tectonic-hydrothermal reformation stage during which pre-enriched Au was remobilized and precipitated to form economic orebodies. Vanadium occurs primarily as V³⁺ in anatase and roscoelite, and in an adsorbed state on goethite and clay minerals. Gold exists predominantly as “invisible gold”, mainly in the form of adsorbed gold (on goethite, illite, kaolinite, and organic matter) and structurally bound Au⁺, with a minor component of nanoparticulate Au⁰. Rare earth element and yttrium (REE + Y) systematics indicate that the ore-forming materials were sourced primarily from the black rock series, which formed in a redox-stratified basin through the mixing of seawater, hydrothermal fluids, and microbial interactions. This two-stage genetic model elucidates the coupled enrichment and differential mobilization of Au and V, providing critical insights for regional exploration.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126362"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685746","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":"Late Mesoarchean crustal reworking/recycling and magma underplating process: Insights from the petrogenesis of 3.0–2.9 Ga potassic granitoids in the Anshan area, North China Craton","authors":"Yufei Xuan ,&nbsp;Jin Liu ,&nbsp;Zhenghong Liu ,&nbsp;Wang Ding ,&nbsp;Liqiang Liu","doi":"10.1016/j.chemer.2025.126361","DOIUrl":"10.1016/j.chemer.2025.126361","url":null,"abstract":"<div><div>The evolution and differentiation of early continental crust remain a fundamental research frontier, with potassic granitoids providing critical insights into these processes. This study investigates the petrogenesis and tectonic setting of Late Mesoarchean (3.0–2.9 Ga) potassic granitoids in the Anshan area of the North China Craton (NCC) through comprehensive geochronological, geochemical, and zircon Hf-O isotopic analyses. Zircon U-Pb dating reveals the studied Late Mesoarchean potassic granitoids include <em>ca.</em> 2.95 Ga Tiejiashan biotite monzogranitic-quartz monzonitic gneisses and <em>ca.</em> 3.0 Ga Donganshan monzogranitic gneisses.</div><div>The Tiejiashan potassic granitoids exhibit high SiO₂ (68.47–75.28 wt%), K₂O (4.32–4.93 wt%) contents, K₂O/Na₂O (1.19–1.53) ratios, low Mg# (23–25) values and strongly negative Eu anomalies (δEu = 0.19–0.31), with metaluminous and ferroan affinities, classifying them as A-type granites. Magmatic zircons yield δ¹⁸O values of+4.66 ‰–+6.10 ‰ and ε_Hf(<em>t</em>) values of −10.61 to −6.34, with T_DM² ages of 4.43–3.99 Ga. The geochemical and Hf-O isotope characteristics suggest that Tiejiashan potassic granitoids originated from partial melting of Eo-Paleoarchean TTGs (3.8–3.3 Ga) under shallow crustal conditions. In contrast, the Donganshan monzogranitic gneisses display higher SiO₂ (75.69–76.14 wt%) and peraluminous signatures, with pronounced LREE-HREE fractionation, moderately negative Eu anomalies (δEu = 0.69–0.80) and unradiogenic Hf isotopes (<em>i.e.</em>, ε_Hf(<em>t</em>) values = −0.85–+1.87, T_DM² age = 3.63–3.39 Ga), indicating Donganshan monzogranitic gneisses originated from partial melting of short-residence TTGs with garnet and amphibole residues. The emplacement of these potassic granitoids records a crustal recycling process, while primary magmatic fabrics (<em>i.e.</em> L ≫ S, L = S) in the <em>ca.</em> 2.95 Ga Tiejiashan pluton suggest high-temperature plastic flow linked to magma underplating. These findings highlight a Late Mesoarchean crustal reworking/recycling process of NCC, driven by the remelting of ancient crust due to magma underplating associated with mantle upwelling in an extensional setting.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126361"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617853","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":"Corrigendum to “Geochemistry of Silurian–Carboniferous sedimentary rocks of the Ulaanbaatar terrane, Hangay–Hentey belt, central Mongolia: Provenance, paleoweathering, tectonic setting, and relationship with the neighbouring Tsetserleg terrane” [Geochemistry (volume 73, issue 4) 481–493]","authors":"Narantuya Purevjav ,&nbsp;Barry Roser","doi":"10.1016/j.chemer.2025.126358","DOIUrl":"10.1016/j.chemer.2025.126358","url":null,"abstract":"","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126358"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617952","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":"Mineralogy, geochemistry and genesis of newly discovered Sinandede kaolin deposit (Balıkesir, NW Türkiye): Potential applications","authors":"Fazlı Çoban ,&nbsp;Şenel Özdamar ,&nbsp;Oral Sarıkaya ,&nbsp;Gökhan Büyükkahraman ,&nbsp;Zeynep Döner ,&nbsp;Naşide Merve Sütçü","doi":"10.1016/j.chemer.2025.126364","DOIUrl":"10.1016/j.chemer.2025.126364","url":null,"abstract":"<div><div>This paper presents first X-ray diffraction (XRD), scanning electron microscopy (SEM), bulk-rock geochemical analyses, isotopic (O-H-C) and differential thermal analysis-thermogravimetric (DTA-TG), physical and thermal tests of Sinandede kaolin deposit (SKD) formed by hydrothermal alteration of Lower Miocene dacitic-rhyodacitic tuffs. The mineralogical analyses revealed that the SKD comprises mainly kaolinite with dickite, illite, smectite-chlorite, Ca-montmorillonite, alunite, halloysite, feldspar, quartz, opal CT, hematite and anhydrite. Geochemically, Al₂O₃, H₂O, Sr, S and Zr contents were markedly enriched, while Rb, Cs, U, Y and Ba were depleted compared with the parent rocks. The chondrite-normalized rare earth element (REE) patterns show identical trends characterized by light rare earth element (LREE) enrichment (La/Sm)_CN = 1.96–10.96 and (La/Yb)_CN = 20.51–37.08), heavy rare earth element (HREE) depletion (Gd/Yb)_CN = 1.37–5.62), slightly Eu anomaly (Eu/Eu* &lt;1), and positive Gd anomaly (Gd/Gd* = av.1.06). The δ¹⁸O values of the samples vary between +0.48 ‰ and, −4.96 ‰; δD values vary between −81.05 ‰ and − 89.97 ‰. On the other hand; δ¹³C (VPDB) values ranging between −25.70 ‰ and − 28.83 ‰ (VPDB) in kaolin samples are compatible with the δ¹³C (VPDB) values of hydrothermal waters mixed with meteoric water fed by C3 plants, indicating the contribution of meteoric water in SDK. Small positive Ce and Gd anomalies, which indicates the presence of a hypogene-supergene mix, further support the contribution of meteoric water. The SDK was formed as a result of post-magmatic hydrothermal activities at temperatures above 100 °C and influenced by both hypojene and supergene conditions. Technological tests suggest that the SDK can be used for wall and floor tiles in ceramic industry.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126364"},"PeriodicalIF":2.9,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145658900","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":"New geochemical and geochronological findings from the Mesozoic ophiolites and marine rock sequences in the Tauride ribbon continent (southern Turkiye) and implications for the evolution of the Inner - Tauride and Pindos (Greece) seaways within the Mesozoic Neotethys","authors":"Ender Sarifakioglu ,&nbsp;Alican Ozturk ,&nbsp;Yıldırım Dilek ,&nbsp;Bilgehan Yabgu Horasan ,&nbsp;Tamara Bayanova ,&nbsp;Mustafa Sevin ,&nbsp;Muhammed Çoban ,&nbsp;Dmitry Elizarov","doi":"10.1016/j.chemer.2025.126356","DOIUrl":"10.1016/j.chemer.2025.126356","url":null,"abstract":"<div><div>Ophiolites exposed in the Konya region of south-central Anatolia play an important role in understanding the distribution of Neotethyan suture zones and paleogeography in the eastern Mediterranean region. The Dipsizgöl ophiolites consist mainly of upper mantle peridotites, rare ultramafic cumulates, and microgabbro – diabase dykes that locally crosscut the peridotites. Basaltic rocks of the Dipsizgöl ophiolite and the Huğlu Unit display P-MORB composition affected by subduction-affected melts. The Huğlu Unit developed in a continental back-arc setting within the Tauride ribbon continent during the Middle-Late Triassic through Cretaceous. The Dipsizgöl ophiolite is geochemically similar to the ophiolites derived from the Pindos back-arc basin, which opened between the Dinaride–Hellenide microcontinent and the Pelagonia Platform to the west during the Late Triassic. A diabase dyke from the Dipsizgöl ophiolite revealed a Rb–Sr whole-rock isochron age of 183 ± 69 Ma. Although we take into account the possibility of errors arising from processes within the system or external factors, this data indicates that the oceanic basin existed between the Lower Triassic to the latest Lower Cretaceous. This intra-continental back-arc basin was likely part of the Southern Inner-Tauride Ocean (SITO), which constituted the eastern equivalent of the Mesozoic Pindos ocean farther west. The Hatip-Çağırbağı, Yükselen, Yunak, Çeşmelisebil and Altınekin ophiolites in the Anatolides exhibit geochemical characteristics of back-arc to fore-arc environments, and represent the remnants of the Mesozoic Northern Inner-Tauride Ocean (NITO). The U<img>Pb zircon dating of a shoshonitic mafic dyke that crosscuts the Altinekin ophiolitic mélange revealed a 70–85 Ma crystallization age, which is interpreted as the timing of the development of an immature volcanic arc. With the opening of the Neotethys in the late Permian, the Apulian microcontinent, which comprised the Dinaride–Hellenide–Tauride carbonate platforms, broke away from the Gondwana continent and drifted northwards. The Pindos basin was a separate seaway in Neotethys and opened within the Apulian microcontinent in the early? Triassic and closed in the Late Cretaceous–Early Paleocene.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126356"},"PeriodicalIF":2.9,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685747","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":"The multi-stages Sn mineralization process in the Xianghualing orefield: Constraints from cassiterite and vesuvianite UPb geochronology","authors":"Zhang Dexian ,&nbsp;Zhou Jialing ,&nbsp;Fang Ruize ,&nbsp;Xiao Dian ,&nbsp;Hu Ziqi","doi":"10.1016/j.chemer.2025.126360","DOIUrl":"10.1016/j.chemer.2025.126360","url":null,"abstract":"<div><div>The Nanling W<img>Sn belt, a world-class metallogenic province, hosts multi-stages W<img>Sn mineralization, accurately constraining the evolutionary history of these polymetallic deposits is essential for understanding mineralization processes and building up their metallogenic models. The Xianghualing orefield, a significant Sn-polymetallic district within the Nanling W<img>Sn belt, displays notable multistage Sn mineralization. Cassiterite U<img>Pb geochronology on sulfide-type cassiterite ores from the Xinfeng mining area, skarn-type Sn ores from the Tangguanpu mining area, and F1 fault-controlled sulfide-type cassiterite ores in the Xianghualing orefield were involved in this study. The obtained cassiterite U<img>Pb ages are 147.8 ± 1.2 Ma, 145.2 ± 2.8 Ma, and 141 ± 23 Ma, respectively, while a vesuvianite dating result yields 154.7 ± 1.9 Ma. These ages are consistent with previously reported cassiterite U<img>Pb dates from the Tieshaping deposit within the orefield and the Xitian deposit in the northern part of the orefield, extending the temporal frame-work of the Xianghualing Sn mineralization and the southern Hunan Sn-polymetallic mineralization system into the Early Cretaceous. Combined with previous studies on magmatic-hydrothermal fluids associated with Sn mineralization in southern Hunan, we propose that highly evolved Cretaceous granites represent prime exploration targets for Sn deposits in this region.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126360"},"PeriodicalIF":2.9,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571631","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":"Geochemical evolution of geothermal waters in Trans-Himalayas: Implications for critical mineral deposition","authors":"Archisman Dutta ,&nbsp;Parashar Mishra ,&nbsp;Abhijit Mukherjee ,&nbsp;Vivek P. Malviya ,&nbsp;Sanjeet Kumar Verma ,&nbsp;P.K. Singh ,&nbsp;Biswajit Ray","doi":"10.1016/j.chemer.2025.126348","DOIUrl":"10.1016/j.chemer.2025.126348","url":null,"abstract":"<div><div>The hydrothermal fluids of the Trans-Himalayan region host rich deposits of critical elements (e.g. Li, Cs, B, W, etc.), that forms critical energy minerals. We characterize geochemical evolution of hydrothermal waters in Trans-Himalayan region, delineating the origin and dissemination of critical energy minerals as epithermal deposits in the region. Thermal fluids exhibit enrichment in W with maximum value of 1603 μg/L and rare alkalis like Cs and Li, whose peak concentrations reach upto 6976 μg/L, and 6.8 mg/L, respectively. Similarly, soils/altered rocks are characterized by significant levels of Li (116–911 mg/kg), Cs (632.56–3317 mg/kg), Cu (181–343 mg/kg), Hg (11–2540 μg/kg), Sb (108.94–6602 mg/kg), BaSO₄ (27.49–71.13 %), S (37.3 %), and F (84–3848 mg/kg). This study identifies Li-bearing mica minerals in considerable concentrations, alongside epithermal minerals attributing to a paleo-high-temperature regime in the Himalayan geothermal field. A conceptual model has been developed to trace the origin of critical minerals in thermal fluids and spring deposits, suggesting that metals and metalloids degas from felsic magmatic melts, through less-denser geological vapours, primarily as vapour-soluble chloride and sulfide complexes, which mixes with genetically evolved secondary fluids undergoing gas-solution-rock interactions and gets enriched in liquid phase after steam segregation, mainly due to decompression boiling.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126348"},"PeriodicalIF":2.9,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145519728","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":"Early Cretaceous volcanism and correlation with large-scale Au mineralization in the Jiaolai basin, Jiaodong Peninsula: Evidences of geochronology and geochemistry from the Qingshan Group","authors":"Long Zhang ,&nbsp;Dong Li ,&nbsp;Juquan Zhang ,&nbsp;Yongkui Wang ,&nbsp;Ning Xu ,&nbsp;Junfeng Li","doi":"10.1016/j.chemer.2025.126345","DOIUrl":"10.1016/j.chemer.2025.126345","url":null,"abstract":"<div><div>On the western margin of the Jiaolai Basin (JLB), acidic volcanic rocks in the Shiqianzhuang Formation of the Qingshan Group are exposed to the eastern part of the Tan-lu fault zone. Bulk element analyses reveal that the rare earth element (REE) distribution pattern exhibits enrichment in light REEs, depletion in heavy REEs and are enriched in high field strength elements (HFSEs) and depleted in large ion lithophile elements (LILEs). The δEu values indicate negative Eu anomalies. The LA–ICP–MS zircon U<img>Pb ages are 109 ± 1.8 Ma, 115 ± 1.6 Ma and 126 ± 1 Ma, respectively, which are consistent with the range of gold mineralization in Jiaodong Peninsula (JEP). Comparison with the widespread mafic-intermediate-felsic dikes and the regional tectonic evolution of Tan-lu fault, it is concluded that the episodic developments of lithospheric thinning are in accordance with the extensive gold mineralization in the JEP during the Early Cretaceous. The acidic volcanic rocks documented that the JLB evolved from prototype into a volcanic basin, meanwhile, large-scale gold mineralization formed along the secondary branches of the Tan-lu fault in the Early Cretaceous, due to the combined effects of changes in the subduction angle of the Paleo-Pacific Plate, trench migration and changes in the subduction direction.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126345"},"PeriodicalIF":2.9,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145519727","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":"Ediacaran and early-palaeozoic bimodal volcanism in the Ossa-Morena Zone, SW Iberian Massif: New clues for intraplate rifting shortly after the Cadomian Orogeny","authors":"P. Cachapuz ,&nbsp;M. Chichorro ,&nbsp;T. Bento dos Santos ,&nbsp;D.R. Carvalho ,&nbsp;U. Linnemann ,&nbsp;M. Zieger-Hofmann ,&nbsp;J. Zieger ,&nbsp;E. Dantas ,&nbsp;R.V. Santos ,&nbsp;P. Moita ,&nbsp;M. Beltrame ,&nbsp;A.R. Solá ,&nbsp;M. Díaz-Azpíroz ,&nbsp;C. Fernández","doi":"10.1016/j.chemer.2025.126351","DOIUrl":"10.1016/j.chemer.2025.126351","url":null,"abstract":"<div><div>This study focuses on bimodal meta-volcanic rocks present in the Iberian Massif, in the Évora-Aracena Metamorphic Belt of the Ossa-Morena Zone (OMZ), near the boundary with the South Portuguese Zone. New petrological, geochemical (whole-rock and Sr<img>Nd isotopes) and LA-ICP-MS U<img>Pb zircon geochronology data are presented to track the magmatic evolution of both felsic and mafic rocks and their respective geodynamic setting during the transition between the Cadomian Orogeny and subsequent Palaeozoic rifting events.</div><div>Our research shows that the Évora-Aracena Metamorphic Belt (EAMB) in the southwestern OMZ possesses a significant record of the transition between the Cadomian and Variscan cycles. U<img>Pb geochronological data confirm the existence of both felsic and mafic Ediacaran igneous rocks (546 and 556 Ma, respectively), a novelty in the region. The Cadomian-related felsic rocks show geochemical similarities to meta-felsic rocks formed during the initial phases of the Cambrian rifting event, namely very negative εNd values (−10.1 to −11.8), depleted HREE patterns and orogenic signatures. Such similarities imply that meta-felsic rocks formed in the earliest stages of the Cambrian Rift-to-Drift event resulted from a shallower melting.</div><div>Moreover, meta-felsic rocks formed in the early stages of the Cambrian rifting (525 Ma) present a significant amount of Ediacaran aged zircons, whereas the Cadomian-related counterparts display a few discordant Cambrian ages, likely a consequence of Pb-loss. This indicates that the convergent, subduction-related regime that prevailed during most of the Cryogenian-Ediacaran times along the boundaries of NW Gondwana was swiftly supplanted by a rift-dominated regime during the Cambrian, with no substantial gap between these two thermal events. Meanwhile, meta-felsic rocks formed during the Rift-to-Drift (525–480 Ma) event exhibit progressively higher εNd values (−5.0 to +3.0), HREE-enrichment, as well as anorogenic signatures, denoting an increasing contribution of mantle-derived melts. This increasing mantle contribution eventually led to the occurrence of bimodal magmatism in the Middle Cambrian Main Rift event. Such Cambrian mafic rocks, unlike the Ediacaran mafic rocks that present flat REE patterns and continental arc signatures, display varying degrees of LREE enrichment and N-MORB to <em>E</em>-MORB signatures.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126351"},"PeriodicalIF":2.9,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571633","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}