Lithos最新文献

{"title":"The Vitória dike swarm – A key piece in the puzzle of low-Ti tholeiitic magmatism of the South Atlantic Magmatic Province","authors":"Antomat A. Macêdo Filho ,&nbsp;Valdecir A. Janasi ,&nbsp;Alisson L. Oliveira ,&nbsp;Elton L. Dantas ,&nbsp;Dawid Szymanowski ,&nbsp;Lucas M. Lino ,&nbsp;Mário Neto Cavalcanti de Araújo ,&nbsp;Maria Helena Hollanda","doi":"10.1016/j.lithos.2025.108360","DOIUrl":"10.1016/j.lithos.2025.108360","url":null,"abstract":"<div><div>During the Early Cretaceous, widespread tectono-magmatic activity along the South Atlantic Rift System led to the development of a complex system of sedimentary basins accompanied by basaltic, silicic, and alkaline magmatism. In the northern Mantiqueira Province (Espírito Santo, Brazil), the Vitória–Ecoporanga belt marks an intensely fractured/faulted NW–SE structural belt that hosts the Vitória dikes, representing the northernmost mafic dike swarm of the Paraná–Etendeka Magmatic Province (PEMP). The dikes are microgabbros composed of plagioclase, clinopyroxene, and Fe<img>Ti oxides, with MgO contents of 3.8–7.2 wt% and total alkalis of 2.4–4.8 wt%, consistent with subalkaline/tholeiitic basaltic compositions. They display enrichment in large-ion lithophile elements and pronounced negative Nb<img>Ta anomalies relative to Rb, Ba, U, Th, K, La, Ce, and Pb. Isotopic compositions show variable ⁸⁷Sr/⁸⁶Sr_(i) (0.70575–0.70994), εNd_(i) (−11.4 to −0.95), and heterogeneous Pb isotopic ratios (²⁰⁶Pb/²⁰⁴Pb = 16.7–18.2; ²⁰⁷Pb/²⁰⁴Pb = 15.4–15.6; ²⁰⁸Pb/²⁰⁴Pb = 37.6–38.9). K<img>Ar and ⁴⁰Ar/³⁹Ar data constrain the emplacement to the Early Cretaceous. Comparative geochemical, isotopic, and geochronological data reveal strong affinities between the Vitória and Riacho do Cordeiro dikes of the Equatorial Atlantic Magmatic Province (EQUAMP). These similarities indicate that both systems share a common evolutionary history, representing remnants of a possibly interconnected low-Ti tholeiitic magma plumbing system active during the early stages of West Gondwana breakup. Comparable compositional affinities are also recognized in other low-Ti tholeiites across the PEMP and EQUAMP. Collectively, this transcontinental low-Ti tholeiitic event represents the earliest stage of the South Atlantic Magmatic Province (SAMP).</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108360"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 Cretaceous granitic magmatism and W-Sn mineralization in Northeast Vietnam: similarity and differences with SW South China","authors":"DinhLuyen Nguyen ,&nbsp;Rucheng Wang ,&nbsp;Jinhai Yu ,&nbsp;Xiao-Lei Wang ,&nbsp;TrungHieu Pham ,&nbsp;Truong Xuan Le ,&nbsp;Lang Xia ,&nbsp;VanNam Pham","doi":"10.1016/j.lithos.2025.108362","DOIUrl":"10.1016/j.lithos.2025.108362","url":null,"abstract":"<div><div>Northeast Vietnam hosts Late Cretaceous granitic magmatism and genetically related W-Sn mineralization. Detailed zircon U-Pb analyses indicate that the Thien Ke granites were formed at 89–87 Ma and the Da Lien granites formed at 89–88 Ma, making them synchronous with the Pia Oac granites in NE Vietnam and numerous Late Cretaceous granites in Southwest South China. Cassiterite U-Pb dating constrains a later mineralization age of ∼82 Ma for Thien Ke W deposit, implying <em>ca</em> 5–7 Myr evolution from high-temperature magmatism to low-temperature mineralization. In contrast, the formation of the Nui Phao W-polymetallic deposit was nearly synchronous with the intrusion of the Da Lien granite, consistent with high-temperature mineralization. These granites have high A/CNK (&gt;1.1), K₂O/Na₂O, Rb/Sr and Rb/Ba, low CaO/Na₂O ratios (&lt;0.3) and variable zircon Hf isotopic compositions (Ԑ_Hf(t) = −6.0 to −14.2), characteristic of S-type granites. Integrating the geochemical and Hf-isotope compositions of the basement metamorphic rocks confirms that Late Cretaceous granites in NE Vietnam originated from partial melting of Neoproterozoic metapelitic sedimentary rocks. Although the Late Cretaceous granites in NE Vietnam have similar S-type granitic geochemistry, crystallization ages and associated rare-metal deposits to those in SW South China, the latter exhibit greater bulk-compositional complexity, extended formation durations and contrasting deposit types. Late Cretaceous granites in NE Vietnam are generally associated with W-polymetallic mineralization, whereas those in SW South China are associated with giant Sn-polymetallic mineralization. The differences in deposit type between the two regions are attributed to the different Sn and W abundances and rock types (pelitic/psammitic) of their sources and different melting conditions. The high-temperature melting of psammitic sources with high Sn abundances in SW South China generated Sn-rich magmas, whereas low-temperature melting of pelitic sources with high W abundances in NE Vietnam led to the production of W-rich melts.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108362"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 behavior of Se and Te during porphyry Cu-associated magmas evolution in the Middle-Lower Yangtze River metallogenic belt: Implications for Se and Te enrichment in porphyry Cu systems","authors":"Yilun Jin ,&nbsp;Guiqing Xie ,&nbsp;Jingwen Mao ,&nbsp;Zhaochong Zhang","doi":"10.1016/j.lithos.2025.108364","DOIUrl":"10.1016/j.lithos.2025.108364","url":null,"abstract":"<div><div>Porphyry Cu systems are the major source of critical metals such as Se and Te; however, the factors controlling Se and Te enrichment during the evolution of porphyry Cu-associated magmas remain poorly understood. Here, we present new whole-rock major and trace element (including Se, Te, and platinum-group elements) and Sr<img>Nd isotope data for gabbros and granitoids associated with Se- and Te-rich porphyry-skarn Cu deposits in the Daye and Jiurui ore districts, Middle-Lower Yangtze River metallogenic belt, Eastern China. New and published whole-rock geochemistry data collectively demonstrate that these rocks are comagmatic and formed through fractional crystallization of primitive magmas derived from a subduction-metasomatized mantle source. Whole-rock Pd and Pt (&lt;0.5–0.82 ng/g and &lt; 0.1–0.19 ng/g, respectively) concentrations are significantly lower than those of primitive arc magmas, yet comparable to sulfide-saturated arc magmas, including porphyry Cu-associated systems, at similar MgO. Numerical modeling indicates that segregation of ∼0.3 wt% of monosulfide solid solution (MSS)-dominated sulfide during magma differentiation can reproduce the observed Pd abundances. Extending this modeling framework to Se and Te suggests that, under oxidized conditions [ΔFMQ (<em>f</em>_O2 values relative to the fayalite–magnetite–quartz buffer) = +1 to +1.5], early MSS-dominated saturation exerts only limited impact on their behavior. By the time of fluid exsolution, Se and Te concentrations in oxidized, sulfide-saturated magmas may exceed those in reduced systems (ΔFMQ &lt; −1.3) by up to an order of magnitude. However, whole-rock Se and Te concentrations (&lt;20–68 ng/g and &lt; 1–7.2 ng/g, respectively) are markedly lower than modeled values at comparable MgO and exhibit decreasing Se/Pd and Te/Pd (fluid-mobile/fluid-immobile) with declining Se and Te. These obeservations indicate that late-stage fluid exsolution can significantly deplete Se and Te from the residual melt. Elevated magmatic <em>f</em>_O2 ensures that sufficient Se and Te remain in the melt at the onset of fluid saturation, thereby allowing the exsolution of Se- and Te-rich fluids, while the fluid reservoir is dominated by magmatic H₂O. Magmas associated with the Daye and Jiurui porphyry-skarn Cu deposits have been reported to be both oxidized and H₂O-rich, which together may account for their significant Se and Te endowments.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108364"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 Kalaymyo Ophiolite: Insights into mantle-melt interaction and tectonic transition from mid-ocean ridge to supra-subduction zone setting in the eastern Neo-Tethys","authors":"Gyuseung Park ,&nbsp;Chul-Ho Heo ,&nbsp;Sun Ki Choi ,&nbsp;Seunghee Han ,&nbsp;Jonguk Kim ,&nbsp;Mi Jung Lee","doi":"10.1016/j.lithos.2025.108373","DOIUrl":"10.1016/j.lithos.2025.108373","url":null,"abstract":"<div><div>The collision between the Indian plate and the West Burma Block led to the formation of Neo-Tethyan ophiolite along the Western Ophiolitic Belt (WOB). The ophiolitic rocks in the WOB exhibit geochemical characteristics of both mid-ocean ridge (MOR) and supra-subduction zone (SSZ) settings, implying a complex geodynamic evolution. However, the processes responsible for such diverse geochemistry remain a topic of debate. This study investigates the petrogenesis of podiform chromitite and associated peridotite in the Kalaymyo ophiolite, located in the central WOB, through petrography, mineral and whole-rock geochemistry, and geochemical modeling. Five groups with distinct textures and chemical compositions are noticed: Group 1, Group 2, and plagioclase spinel (Pl-Spl) peridotite, dunite, and chromitite. Group 1 peridotite represents residual mantle in MOR settings, as shown by its geochemical similarity with the modern abyssal peridotite and partial melting modeling. Pl-Spl peridotite, containing intergranular plagioclase, is characterized by elevated HREE contents in clinopyroxene and high Ti in spinel, suggesting localized MORB-like melt impregnation. Dunite and chromitite display enrichment of incompatible elements in clinopyroxene and chromite with high oxygen fugacity value, collectively suggesting their formation in SSZ environments. Clinopyroxene oikocryst in chromitite is comparable to that of modern island-arc tholeiite with relative Ba enrichment and Nb depletion, further supporting its SSZ origin. Group 2 peridotites record the intermediate stages of the melt-mantle interaction including hydrous melting and reactive melt percolation under SSZ settings, as supported by intermediate chemical composition, amphibole inclusions, and melt-mantle interaction modeling. We propose that the coexistence of MOR-type and SSZ-type lithologies in the Kalaymyo ophiolite reflects in-situ tectono-magmatic transition rather than tectonic juxtaposition via mélange formation. This interpretation is supported by transitional variations in lithology and geochemistry and the spatial association of SSZ-type rocks with dunite and podiform chromitite bodies.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108373"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From spreading to subduction: Timelines of induced subduction zones recorded in the Central Palawan Ophiolite","authors":"Gabriel Theophilus V. Valera ,&nbsp;Betchaida D. Payot ,&nbsp;Tetsuo Kawakami ,&nbsp;Shuhei Sakata ,&nbsp;Sota Niki ,&nbsp;Takafumi Hirata","doi":"10.1016/j.lithos.2025.108346","DOIUrl":"10.1016/j.lithos.2025.108346","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Exposures where the petrological evolution of the nascent island arc and the slab-mantle wedge interface can be investigated provide unique opportunities to understand incipient stages of subduction. In this study, novel petrological information on the layered mafic-ultramafic sequence of the central Palawan ophiolite (CPO) and radiometric age dates for its metamorphic sole are presented. The CPO is a Late Eocene-Early Oligocene fossil oceanic lithosphere which experienced Tethyan-type subduction following an inferred mid-ocean ridge inversion. Mafic-ultramafic sequences of the CPO are exposed in Simpocan (gabbronorites) and Bacungan (olivine websterites, clinopyroxenites, dunites and minor gabbronorite). These rocks represent the lower crust to upper mantle cumulate section of this fossil island arc based on the low olivine forsterite (Fo&lt;sub&gt;86–88&lt;/sub&gt;) and NiO content (= 0.10–0.27 wt%), high spinel Cr# (= 0.55–0.65), and high plagioclase anorthite content (An&lt;sub&gt;89–94&lt;/sub&gt;). The mafic-ultramafic cumulates likely represent magmas that stagnated beneath a juvenile island arc at or near the Moho Transition Zone based on their obtained equilibration conditions (830–940 °C; 5–7 kbars).&lt;/div&gt;&lt;div&gt;In order to constrain the timing of the subduction event, zircons were separated from the metamorphic sole of the CPO referred to as the Dalrymple Amphibolite. Specifically, U&lt;img&gt;Pb ages (lower intercept age = 35.20 ± 0.26 Ma) were obtained for the metamorphic overgrowth rims of the matrix sample B214-2G. These rims have lower Th/U ratios (= 0.04–0.34) than the inherited cores (0.25–3.35). Previous works on the petrogenesis and &lt;em&gt;P-T-D&lt;/em&gt; history of B214-2G have shown that this kyanite-garnet-biotite-hornblende-staurolite schist preserved peak metamorphic conditions (∼700 °C, 13 kbars) and was less affected by later retrograde metamorphic stage. Our results reveal the timing of prograde metamorphism of the subducting slab at moderately low &lt;em&gt;P/T&lt;/em&gt; gradients (∼16 °C/km) linked with incipient subduction. Together with compiled radiometric ages for the CPO by previous works (= 40.01 Ma), these results indicate that subduction begun at ∼35 Ma. Furthermore, adopting the spreading to subduction inversion hypothesis of previous studies would suggest that subduction in the region was initiated within five million years of CPO-related oceanic spreading. The age of metamorphism presented in this work (= 35.20 ± 0.26 Ma) thus possibly indicate a rapid rate of reversal from spreading to subduction in induced subduction zones. The paleogeothermal gradient preserved in the Dalrymple Amphibolite is however significantly cooler than other ophiolites. Our results further document the short timeframe (∼1–2 Ma) needed to cool the slab-mantle interface from the high &lt;em&gt;T/P&lt;/em&gt; gradients during very early stages of subduction initiation (&gt;25 °C / km), to geothermal gradients more comparable to hot subduction zones (∼16 °C/km) which was likely brought","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108346"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Titanium isotope fractionation during granitic magma evolution: A case study of the Fangshan pluton, North China craton","authors":"Chunxia Yi ,&nbsp;Xinmiao Zhao ,&nbsp;Tao Shi ,&nbsp;Jin Li ,&nbsp;Bing Liu ,&nbsp;Junjie Luo ,&nbsp;Jian Zhao ,&nbsp;Xiaojun Wang ,&nbsp;Fang Liu ,&nbsp;Xiangkun Zhu ,&nbsp;Hongfu Zhang","doi":"10.1016/j.lithos.2025.108357","DOIUrl":"10.1016/j.lithos.2025.108357","url":null,"abstract":"<div><div>To elucidate the geochemical behavior and fractionation mechanisms of titanium (Ti) isotopes during granitic magma evolution, we conducted a systematic Ti isotopic analysis of I-type granodiorites, quartz diorites, and their associated mafic microgranular enclaves (MMEs), along with major Ti-bearing minerals biotite, hornblende, and titanite from the Early Cretaceous Fangshan pluton, North China Craton (NCC). The granodiorites and quartz diorites exhibit a narrow range of δ^49/47Ti values (+0.14 ‰ to +0.25 ‰; average + 0.18 ± 0.07 ‰, 2SD, <em>n</em> = 15), comparable to that of the upper continental crust (UCC, δ^49/47Ti = +0.18 ± 0.07 ‰; 2SD). These values show no discernible correlation with conventional magmatic differentiation indices (e.g., SiO₂, TiO₂, MgO), suggesting limited Ti isotope fractionation during I-type granite differentiation. Thermodynamic modeling and mass balance calculations indicates that the isotopically enriched Ti signatures of the Fangshan granodiorites and quartz diorites result from partial melting (5–20 %) of rutile-bearing eclogitic sources in a thickened lower crust. In contrast, the MMEs display a wider range of δ^49/47Ti values (+0.04 ‰ to +0.33 ‰) that correlates with SiO_2, TiO₂, and MgO contents, consistent with mixing between mantle-derived mafic and crustal-derived felsic magma, coupled with fractional crystallization. Mineral separates reveal clear intra-mineral Ti fractionation: titanite is consistently enriched in lighter Ti isotopes (δ^49/47Ti = −0.09 ‰ to +0.09 ‰) relative to coexisting biotite (+0.22 ‰ to +0.44 ‰) and hornblende (+0.16 ‰ to +0.35 ‰), consistent with differences in the Ti coordination environments between the melt and crystallizing mineral. Taken together with previous studies, our results demonstrate that although Ti isotopes alone offer limited discrimination between I- and S-type granites, they act as a reliable tracer of A-type granites, where extensive fractional crystallization produces pronounced Ti isotope fractionation. Overall, these findings advance our understanding of Ti isotope behavior in granitic systems and highlight their potential as a tracer for granite petrogenesis and crustal evolution.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108357"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 Early Cretaceous granitoids in the northern Lhasa margin, Tibet: Implications for the southward subduction of the Bangong-Nujiang Meso-Tethys Ocean","authors":"Wei Chen ,&nbsp;Miao Sun ,&nbsp;Xudong Ma ,&nbsp;Yang Song ,&nbsp;Zhi Zhang ,&nbsp;Jiajia Yu ,&nbsp;Mengxiang Di ,&nbsp;Chang Liu ,&nbsp;Shuhao Zhang ,&nbsp;Juxing Tang","doi":"10.1016/j.lithos.2026.108413","DOIUrl":"10.1016/j.lithos.2026.108413","url":null,"abstract":"<div><div>Debates persist over the tectonic evolution of the Bangong-Nujiang Meso-Tethys Ocean (BNTO), especially the hypothesis about its southward subduction. There is a lack of evidence for its southward subduction beneath the northern Lhasa terrane due to the presence of sedimentary cover and ambiguous geodynamic interpretations. To address this issue, this study investigated the Early Cretaceous granitoids (116–108 Ma) in the Xiongmei-Bange area located along the northern margin of the Lhasa terrane. The results indicate that the granitoids consist of two distinct suites: peraluminous and metaluminous granitoids. Among these, the peraluminous granitoids exhibit A/CNK ratios ranging from 1.03 to 1.47 and moderate enrichment in isotopic signatures, with ε_Hf(t) and ε_Nd(t) values varying from −5.1 to +2.4 and from −10.7 to −5.9, respectively. These granitoids were derived from the amphibolitic lower crust metasomatized by subducted sediments. In contrast, the metaluminous granitoids manifest A/CNK ratios ranging from 0.99 to 1.06, high enrichment in Nd<img>Hf isotopes, with ε_Hf(t) and ε_Nd(t) values ranging from −8.7 to −0.9 and from −11.2 to −8.0, respectively, and elevated Mg# values varying from 50 to 63. They originated from the partial melting of the ancient lower crust, with significant mantle-derived contributions, a source composition indicated by their metaluminous character, enriched Nd<img>Hf isotopes, and elevated Mg#, which collectively reflect limited influence from subducted sediments compared to the peraluminous suite. The results suggest that the southward subduction of the BNTO may have commenced during the Middle Jurassic, with slab rollback at about 130 Ma and subsequent slab breakoff at around 115 Ma potentially triggering asthenospheric upwelling. This process could have induced lithospheric mantle melting and crustal anatexis, leading to the formation of the two granitoid suites. Slab rollback and breakoff are interpreted to have destabilized the overriding plate, causing the lithospheric subsidence in the northern Lhasa terrane during the Early Cretaceous. This subsidence likely induced a major marine transgression (Langshan Formation, 115–98 Ma). Consequently, the Jurassic - Early Cretaceous magmatic arc was covered by shallow-marine carbonates, effectively masking direct evidence of southward subduction. By integrating slab dynamics (i.e., possible rollback and subsequent breakoff) with the burial history, this study proposes a model that addressed the long-standing debate over the apparent absence of an arc-trench system.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108413"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Segmented Paleo-Tethys subduction and its role in driving Triassic magmatism within the Elashan Tectonic-Magmatic Belt, northern Tibetan Plateau","authors":"Tengfeng Miao ,&nbsp;Xu Zhao ,&nbsp;Jan Marten Huizenga ,&nbsp;Xiaolong Li ,&nbsp;Lianxin Lai ,&nbsp;Bin Li ,&nbsp;Hongtao Zhu ,&nbsp;Xinxin Zhang ,&nbsp;Hongzhi Zhou ,&nbsp;Junhao Wei","doi":"10.1016/j.lithos.2025.108387","DOIUrl":"10.1016/j.lithos.2025.108387","url":null,"abstract":"<div><div>Segmented subduction redirects mantle flow and melt, controlling orogenic magmatism and deformation. The Elashan Tectonic-Magmatic Belt (ETMB) lies between the East Kunlun (EKOB) and West Qinling (WQOB) orogenic belts, linked to Triassic Paleo-Tethys subduction. We present geological, geochemical, zircon U<img>Pb geochronological, and Hf-Sr-Nd isotopic data from Triassic ETMB granites, supplemented by data from the EKOB and WQOB. The ca. 244 Ma Shiduolong granodiorites display high MgO and enriched ε_Hf (t) (−6.8 to −3.6) values, indicating mixing between crust-derived felsic and mantle-derived mafic melts. The ca. 229 Ma Huda diorites, with low Sr/Y and depleted ε_Hf (t) (−3.0 to -0.7) values, originated from a shallow juvenile lower crust at high-temperature conditions. The Saishitang complex comprises ca. 220 Ma quartz diorite porphyrites and granodiorites, plus ca. 215 Ma diorites. The quartz diorite porphyrites exhibit high-Mg andesite affinities and linear (⁸⁷Sr/⁸⁶Sr)_i-SiO₂ correlation, suggesting partial melting of enriched mantle peridotites with assimilation and fractional crystallization. The granodiorites display high-Mg adakitic characteristics formed by melting of delaminated lower crust. The diorites are geochemically similar to the Huda diorites but exhibit more enriched ε_Hf (t) values (ranging from −9.2 to −4.8), suggesting an older and deeper crustal source. Notably, the 240–230 Ma ETMB granitoids record high ε_Hf (t) values and a depletion trend, which is in contrast with the concurrent enrichment in the adjacent EKOB and WQOB. This implies that, although they were in a contiguous subduction setting, unique dynamics related to the asthenosphere upwelling occurred in the ETMB, related to a slab window between the EKOB and WQOB. The inferred slab window was likely produced by slab tearing, controlled by slab segmentation in response to an along-strike transition from slab rollback in the WQOB to a relatively low-angle subduction regime in the EKOB.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108387"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Equilibrium tellurium isotope fractionation in tellurides: A first-principles study","authors":"Jiaxin Liang ,&nbsp;Yang Zhao ,&nbsp;Huiquan Tian ,&nbsp;Shanqi Liu ,&nbsp;Yongbing Li","doi":"10.1016/j.lithos.2025.108355","DOIUrl":"10.1016/j.lithos.2025.108355","url":null,"abstract":"<div><div>Tellurium is a critical metal that is highly concentrated in tellurides, which also serve as important hosts of gold, silver, and platinum-group elements. Understanding the stable isotopic behavior of Te in tellurides is crucial not only for elucidating the formation and evolution of Te-bearing hydrothermal ore systems but also for constraining the genetic mechanisms of gold deposits. However, Te isotope fractionation in tellurides remains poorly characterized and inadequately understood. In this study, first-principles calculations were used to determine Te isotope fractionation between tellurides and native tellurium. The reduced partition function ratios of ¹³⁰Te/¹²⁵Te are found to decrease in the following order: frohbergite (FeTe₂) &gt; mattagamite (CoTe₂) &gt; vulcanite (CuTe) &gt; pampaloite (AuSbTe) &gt; petzite (Ag₃AuTe₂) &gt; melonite (NiTe₂) &gt; sylvanite (AuAgTe₄) ≥ coloradoite (HgTe) ≥ stützite (Ag₅Te₃) &gt; krennerite (Au₃AgTe₈) &gt; hessite (Ag₂Te) &gt; calaverite (AuTe₂) ≥ montbrayite (Au₂Te₃) &gt; tellurantimony (Sb₂Te₃) ≥ skippenite (Bi₂Se₂Te) ≥ Joséite-A (Bi₄TeS₂) &gt; tellurobismuthite (Bi₂Te₃) &gt; native tellurium ≥ tsumoite (BiTe) &gt; altaite (PbTe). The <em>β</em>₁₃₀_–₁₂₅ factors of tellurides show a weak correlation with Te coordination number, but they exhibit a negative correlation with the average length of chemical bonds formed by Te when minerals are grouped by Te coordination number and oxidation state. Our results provide a theoretical basis for determining whether isotopic equilibrium has been achieved in natural samples and enable more accurate interpretations of variations in Te isotopic compositions. This, in turn, advances our understanding of the formation and evolution of gold-telluride deposits.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108355"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 and mineralogical study of zircon, apatite, and wolframite in the Xiatongling W-Mo-Be deposit, South China: Implications for key factors to W-Mo-Be mineralization","authors":"Yiming Chen ,&nbsp;Xiaoyong Yang ,&nbsp;Jiandong Sun ,&nbsp;Yu Wang","doi":"10.1016/j.lithos.2025.108398","DOIUrl":"10.1016/j.lithos.2025.108398","url":null,"abstract":"<div><div>The Xiatongling tungsten‑molybdenum‑bismuth (W-Mo-Be) deposit, located in the Nanling metallogenic belt, is a stockwork and quartz vein-type W-Mo-Be system developed within and along the contact zone of a medium- to fine-grained granite intrusion. Although previous studies have focused on the magmatic age and geochemical features of the intrusion, and indirectly constrained the mineralization age using molybdenite geochronology, the precise metallogenic chronology, sources of ore-forming materials, and key factors controlling W-Mo-Be mineralization remain poorly understood. This study presents an integrated geochemical and geochronological investigation of zircon, apatite, and wolframite from the deposit to constrain its petrogenesis and mineralization. The zircon U–Pb age of the granite (ca. 154 Ma) corresponds to the wolframite U–Pb age (ca. 154 Ma), establishing a genetic link between magmatism and tungsten mineralization. Geochemical data indicate that the granite is weakly peraluminous (A/CNK = 1.03 to 1.08), characterized by high SiO₂, U, and Ta, and low Ba, Sr, and Zr + Nb + Ce + Y, typical of highly fractionated S-type granites. Zircon ε_Hf(t) values of −7.75 to −10.64 and apatite ε_Nd(t) values of −15.56 to −8.97 indicate derivation from the Proterozoic metasedimentary basement of the Wugongshan area, which was characterized by pre-enrichment in W, Mo, and Be. Integrated whole-rock and wolframite geochemical data reveal consistent and pronounced negative Eu anomalies in both wolframite and the Xiatongling granite. Combined with robust geochronological constraints, these findings support the interpretation that the reduced ore-forming fluids were directly exsolved from the reduced, granitic magma. Based on the integrated evidence, we conclude that pre-enrichment of the source and extensive fractional crystallization were key factors for the formation of the Xiatongling W-Mo-Be deposit.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108398"},"PeriodicalIF":2.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}