Lithos最新文献

{"title":"Petrogenesis of high-Mg diorite dike bearing granitic xenoliths in the Jiaodong Peninsula, eastern North China Craton","authors":"Tong Qu ,&nbsp;Yayun Liang ,&nbsp;Lei Shu ,&nbsp;Christoph Beier ,&nbsp;Wengang Liu ,&nbsp;Haiyi Wang ,&nbsp;Chenxi Zhang ,&nbsp;Chao Yu ,&nbsp;Jun Deng","doi":"10.1016/j.lithos.2025.108396","DOIUrl":"10.1016/j.lithos.2025.108396","url":null,"abstract":"<div><div>Early Cretaceous magmatism in the Jiaodong Peninsula, northeastern North China Craton (NCC), is widespread, but the mechanisms of tectonic transition in a subduction setting and the associated lithospheric response remain debated. Here we investigate the petrology and geochemistry of a high-Mg diorite dike containing granitic xenoliths in the northwestern Jiaodong Peninsula. Zircon U-Pb dating indicates that the diorite formed at ∼126 Ma, while the granitic xenoliths crystallized earlier at ∼130 Ma. The diorite dike samples show elevated MgO (3.3–6.1 wt%) and Mg# (48–64) relative to the granitic xenoliths, as well as high Sr/Y ratios (35–233). The geochemical features of the diorite, combined with negative zircon ε_Hf(t) values (−26.8 to −12.0) and high initial ⁸⁷Sr/⁸⁶Sr ratios (0.7102–0.7113), suggest that they were derived from partial melting of an enriched lithospheric mantle metasomatized by slab-derived fluids, with residual garnet present in the source. The granitic xenoliths exhibit high Sr/Y (≥ 151) and La/Yb (≥ 26) ratios, negative ε_Nd(t) (−21.7 to −11.2), and zircon ε_Hf(t) (−23.9 to −13.0), indicating formation by partial melting of thickened lower crust induced by mantle-derived underplating. The combined occurrence of mantle-derived dioritic melts and crustal xenoliths records crust–mantle interaction during lithospheric thinning. We propose a model in which the eastern NCC was affected by prolonged Mesozoic subduction, followed by rollback of the Paleo-Pacific slab and thermo-mechanical-chemical erosion. This rollback triggered asthenospheric upwelling and widespread underplating, which caused transient thickening of the lower crust prior to lithospheric delamination and extensive crust–mantle interaction.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108396"},"PeriodicalIF":2.5,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925793","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":"Dynamic magmatic evolution of boninites from the Challenger Deep, southernmost Mariana Trench: Insights from mineral thermobarometry and MELTS modeling","authors":"Ruolan Lin ,&nbsp;Tao Wu ,&nbsp;Hengrui Zhu ,&nbsp;Jianggu Lu ,&nbsp;Liyan Tian ,&nbsp;Yidi Hong","doi":"10.1016/j.lithos.2025.108381","DOIUrl":"10.1016/j.lithos.2025.108381","url":null,"abstract":"<div><div>Boninite, as a high-MgO volcanic rock closely associated with the subduction initiation, serves as a key medium for understanding plate tectonic dynamics. Although significant advances have been made in understanding boninite petrogenesis within the northern Izu-Bonin-Mariana (IBM) forearc system, research gaps persist in the southern Mariana subduction zone. The paucity of data from the southernmost Mariana Trench (Challenger Deep region) hinders a comprehensive understanding of magmatic evolution across the entire IBM arc system. Here, we present integrated studies of mineral and whole-rock geochemical data of boninite samples collected from the northern slope of the Challenger Deep by the manned submersible <em>Fendouzhe</em>. The studied samples have high MgO (14.6–15.3 wt%) and SiO₂ (57.6–57.9 wt%), but low TiO₂ (∼0.2 wt%) contents, and are highly enriched in fluid-mobile and large ion lithophile elements. They also show typical U-shaped REE patterns. Liquidus modeling indicates a crystallization sequence of olivine → low-Ca pyroxene → high-Ca pyroxene. Low-Ca pyroxenes commonly display calcic overgrowths and complex zoning textures, recording multiple episodes of magma recharge-mixing events and non-equilibrium crystallization. Mineral thermobarometry reveals that there are two magma chambers: a deep chamber (0.41GPa [∼13.5 km], 1214 °C) and a shallow chamber (0.17Gpa [∼5.6 km], 1183 °C). Based on mineral texture, two undercooling events were also identified: the first occurred during the ascent of magma from deep chamber to the shallow chamber, where magma mixing and rapid pressure drop triggered calcic overgrowth textures; the second took place during submarine eruption, where interaction with seawater produced quenched structures. All of these observations indicate that the studied boninites underwent complex magma processes during subduction initiation: frequent magma recharge-mixing and rapid ascent-eruption. Furthermore, the boninites from Challenger Deep and IODP Expedition 352 share many similar geochemical and petrological characteristics. These similarities suggest that both the northern and southern IBM segments experienced broadly comparable magmatic processes during subduction initiation.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108381"},"PeriodicalIF":2.5,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925797","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":"Petrology, geochemistry and geochronology of the Kekeya ash (SW Tarim Basin): Implications for its origin and provenance","authors":"Jia-Jun Mo ,&nbsp;Yu-Ting Zhong ,&nbsp;Man Wang ,&nbsp;Le Zhang ,&nbsp;Qiong Wu ,&nbsp;Qiang Ma ,&nbsp;He Wang ,&nbsp;Jahandar Ramezani ,&nbsp;Xiao-Long Huang ,&nbsp;Fu-Yuan Wu ,&nbsp;Yi-Gang Xu","doi":"10.1016/j.lithos.2025.108391","DOIUrl":"10.1016/j.lithos.2025.108391","url":null,"abstract":"<div><div>The Miocene volcanic ash layer at the Kekeya section, in the southwestern Tarim Basin (NW China), has a debated origin and stratigraphic importance. To clarify whether these deposits are primary air-fall tephra or reworked sediments, we conducted detailed petrographic, mineralogical, geochemical, and zircon U<img>Pb dating analyses. The ash layer contains abundant angular K-feldspar, plagioclase, and volcanic glass fragments with minimal rounding, suggesting direct pyroclastic deposition. Zircon U<img>Pb dating yields a weighted mean ²⁰⁶Pb/²³⁸U CA-ID-TIMS age of 10.997 ± 0.027/0.042/0.044 Ma, consistent with published ⁴⁰Ar/³⁹Ar ages of K-feldspar. The uniform Pb isotopic compositions of K-feldspar (²⁰⁶Pb/²⁰⁴Pb = 17.62–19.03) and Sr isotopic ratios of plagioclase (⁸⁷Sr/⁸⁶Sr = 0.70968–0.71047) indicate a single volcanic source rather than heterogeneous provenance. Comparison with Miocene volcanic rocks from the eastern Pamir reveals geochemical and isotopic affinities to the Dunkeldik volcanic belt. The excellent preservation of primary K-feldspar and other mafic phases suggests limited post-depositional alteration under hyper-arid conditions. These results confirm that the Kekeya ash layer represents primary fallout tephra derived from coeval (∼11 Ma) alkaline volcanism in the eastern Pamir, providing a robust marker horizon for regional Miocene stratigraphy.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108391"},"PeriodicalIF":2.5,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880767","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":"Silica reversal reveals the lithium super-enrichment during the extreme differentiation of granitic magmas","authors":"Chun-Li Guo ,&nbsp;Roberto F. Weinberg ,&nbsp;Fu-Yuan Wu ,&nbsp;Jun-Xing Zhao ,&nbsp;Xiao-Chi Liu ,&nbsp;Bin-Wu Zhang","doi":"10.1016/j.lithos.2025.108380","DOIUrl":"10.1016/j.lithos.2025.108380","url":null,"abstract":"<div><div>Extremely fractionated granitic rocks are commonly associated with rare metal deposits and show a SiO₂ reversal point, where whole-rock SiO₂ content switches from increasing to decreasing as the magma fractionates. This switch goes against expectations of continuous increase in SiO₂ contents with magma differentiation. In this study, we investigated the Ganfang pluton that includes the Baishuidong deposit, China's largest granite-type lithium deposit. The SiO₂ contents in the Ganfang pluton increase from 70.8 to 76.1 wt% before decreasing to 64.0 wt% as the rocks become increasingly fractionated and enriched in Li and other rare metals. Notably, Na₂O, Al₂O₃, MnO, Zn, V, Ba, and Sc also exhibit reversal points as a function of SiO₂, while rare metal elements, like Li, Rb, Cs, Nb, and Ta, show a continuously increasing trend. We find that the SiO₂ reversal is caused by the crystallization of snowball quartz phenocrysts and their fractionation at late stages of magma evolution caused by increased F-content in the melt and stabilization of quartz as the liquidus phase. The reversal point coincides with the transition from a crystal-melt system, lacking an obvious fluid phase, to one dominated by fluid-magma (crystals plus melt) interaction. When this change occurs, Li contents rapidly increase from &lt;1000 ppm to &gt;6000 ppm, and micas become rich in Si and Li, gradually changing from muscovite to lepidolite. This is facilitated by the high concentrations of fluxing components in the melt, such as H₂O, Li, F, and P, that decrease its viscosity and solidus temperature. This allowed for several steps of magma fractionation through efficient extraction of interstitial melt, further concentrating these elements eventually leading to crystallization of Li-rich micas and the mineralization.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108380"},"PeriodicalIF":2.5,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925855","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":"Mesozoic magmatism in the Andes of southern Ecuador and northern Peru: Tectonic insights from whole-rock chemistry and zircon petrochronology","authors":"Leidy Carolina Sandoval Espinel ,&nbsp;Cesar Witt ,&nbsp;Jorge Iglesias ,&nbsp;Massimiliano Zattin ,&nbsp;Olivier Bruguier ,&nbsp;Marc Poujol ,&nbsp;Pablo Samaniego ,&nbsp;Mauricio Bermudez ,&nbsp;John Jairo Sandoval Espinel","doi":"10.1016/j.lithos.2025.108389","DOIUrl":"10.1016/j.lithos.2025.108389","url":null,"abstract":"<div><div>The southern Ecuador–northern Peru region marks the transition between the northern and central Andes. This study reconstructs the Mesozoic magmatic history of this key region by integrating petrography, U<img>Pb geochronology, whole-rock and zircon geochemistry, and εHf_(t) and δ¹⁸O zircon isotopic data from plutonic rocks. Our results indicate that much of the Mesozoic magmatism occurred in an extensional arc setting, with magmatic reservoirs progressively incorporating more depleted, mantle material, while crustal contributions diminished through time. Magmatic reservoirs evolved both spatially and temporally, beginning with an extensive Triassic arc dominated by granitoids exhibiting strong crustal signatures at least until 220 Ma. This was followed by mildly enriched signatures associated with a stationary Jurassic to Early Cretaceous arc active between ∼190 and ∼ 126 Ma. Somewhere in between 126 and 104 Ma, the arc underwent a significant westward migration, potentially driven by slab rollback, which coincided with the opening of the Celica–Lancones Basin and the subsequent emplacement of the Late Cretaceous Celica–Lancones arc onto oceanic basement. This migration is consistent with westward shifts observed in central Ecuador and Colombia but contrasts with coeval eastward migration documented in central and southern Peru. In addition, new U<img>Pb ages challenge current interpretations of a missing Jurassic arc in northern Peru by providing clear evidence that Jurassic magmatism extended at least as far south as 6°S.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108389"},"PeriodicalIF":2.5,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880719","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":"Magma mingling/mixing at Citlaltépetl volcano, eastern Trans-Mexican Volcanic Belt, and the plumbing system during the ∼5 ky BP Jamapa explosive eruption","authors":"José Luis Arce ,&nbsp;José Luis Macías ,&nbsp;Mireya González-Herrera ,&nbsp;Luca Caricchi ,&nbsp;Martin Miranda ,&nbsp;Delphine Sourisseau ,&nbsp;Denis R. Avellán ,&nbsp;Rafael Torres-Orozco","doi":"10.1016/j.lithos.2025.108388","DOIUrl":"10.1016/j.lithos.2025.108388","url":null,"abstract":"<div><div>The active Citlaltépetl volcano (Pico de Orizaba) located in the eastern part of the Trans-Mexican Volcanic Belt, is the highest mountain (5636 masl) in Mexico and North America. Intense explosive and effusive activity took place in the Holocene (mainly with VEI &lt; 5), with some volcanic eruptions that have not yet been described, like the Jamapa Pyroclastic Flow deposit. Jamapa deposits were emplaced up to 4 km from the summit on the northern flank of the volcano, and rest on a paleosol dated at ∼5 ky BP. The deposits consist of subrounded to rounded &gt;30 cm-diameter porphyritic clasts of dacitic pumice (63.6 wt% SiO₂), andesitic scoria (58.9 wt% SiO₂), banded vesicular clasts (59.0 wt% SiO₂), andesitic dense volcanic bombs (62.8 wt% SiO₂), and magmatic crystalline enclaves (64.0 wt% SiO₂). The pumice contains plg + opx + cpx ± Fe-Ti oxides, and rare amph phenocrysts, whilst the scoria and banded clasts contain opx + cpx + amph + plag +/− Fe-Ti oxides. Glass matrix in all samples of the Jamapa Pyroclastic Flow a large compositional range is recorded (dacite to rhyolite; 66.6–78.2 wt% SiO₂), and plagioclase is also heterogeneous (An_23.3 to An₇₈), whereas pyroxene and amphibole are almost homogeneous in all samples. Cpx-liquid and amphibole geothermometry of the Jamapa juvenile components show significant differences among samples: andesitic scoria (900–946 °C), the pumice barren of amphibole (930 °C), and the banded sample (970–986 °C). On the other hand, the “MagMaTaB” liquid geothermobarometer model yielded 884 °C for the scoria, 934 °C for the banded, and 898 °C for the pumice samples. P-T results suggest the occurrence of at least two magmatic reservoirs beneath the volcano: a deep (∼20 km), relatively mafic, and volatile-rich reservoir and a shallow (∼8 km) reservoir with a felsic, stagnant magma. These results and the heterogeneous composition of the glass matrix and plagioclase crystals suggest that not only mingling but also mixing occurred during the Jamapa volcanic event. We conclude that a mafic magma stored at a depth of ∼20 km ascended to reach the dacitic reservoir located ∼8 km below the volcano, where both magmas were partially mixed, provoking overpressure of the system and eventually triggering the explosive eruption, destroying a pre-existing dome.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108388"},"PeriodicalIF":2.5,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880720","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 Late Mesozoic granitoids in the Edong-Jiurui mining district, eastern China: Magmatic response to the Paleo-Pacific Plate subduction","authors":"Yi-Zeng Yang ,&nbsp;Jun He ,&nbsp;Wolfgang Siebel ,&nbsp;Shuang-Qing Li ,&nbsp;Tongfei Li ,&nbsp;Taotao Li ,&nbsp;Yang Chen ,&nbsp;Fukun Chen","doi":"10.1016/j.lithos.2025.108393","DOIUrl":"10.1016/j.lithos.2025.108393","url":null,"abstract":"<div><div>The petrogenesis of Late Mesozoic granitoid rocks in the Edong-Jiurui mining district is critical for understanding the genetic relationship between magmatism and copper‑iron mineralization in eastern China. Here we present whole-rock geochemical and Sr-Nd-Pb isotopic data coupled with zircon trace elemental and Hf isotopic compositions for Late Jurassic to Early Cretaceous ore-related granitoid rocks in this district. Zircon U-Pb isotopic ages demonstrate that the granitoid rocks associated with the iron deposits formed at ca. 128–122 Ma, those associated with the iron‑copper deposits at ca. 138–133 Ma, and those associated with the copper deposits at ca. 145–140 Ma. The iron-related rocks have high SiO₂ and K₂O contents, low Mg^# values, and peraluminous, A-type affinities. The earlier-episode iron‑copper- and copper-related granitoids have similar geochemical features and can be classified as high-K adakitic rocks. All the rocks show enriched Sr-Nd isotopic compositions similar to synchronous mantle-derived mafic rocks. High radiogenic Pb and decoupled Nd-Hf isotopic compositions of the early-episode rocks suggest the incorporation of recycled terrigenous sedimentary components in the magma sources. The three stages of magmatic rocks show arc-like geochemical characteristics, high-K affinity, and progressively decreasing oxygen fugacity (<em>f</em>O₂) conditions and Sm/Yb ratios as well as an increase in magma temperature with decreasing age. It can be proposed that the older rocks (ca. 145–140 Ma and ca. 138–133 Ma) were derived from high-pressure, low-temperature partial melting of H₂O-rich, high- <em>f</em>O₂ subducted oceanic crust and recycled terrigenous sediments, induced by mantle diapirism during slab rollback. In contrast, the younger ones originated from a relatively H₂O-poor, low- <em>f</em>O₂ juvenile lower-crustal source, with minor contributions from slab- or mantle-derived melts/fluids. The partial melting of the juvenile lower crust source has been driven by asthenospheric upwelling at low pressure and high temperature during the subduction of the Paleo-Pacific slab.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108393"},"PeriodicalIF":2.5,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880718","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 Paleoarchean felsic crustal terranes of the Bastar craton, central India: Constraints from granitoid geochemistry and Nd isotopic compositions with implications for Mesoarchean amalgamation","authors":"Ankita Nandi ,&nbsp;Ravikant Vadlamani ,&nbsp;Chris Clark","doi":"10.1016/j.lithos.2025.108377","DOIUrl":"10.1016/j.lithos.2025.108377","url":null,"abstract":"<div><div>Archean continental crust is dominated by voluminous tonalite-trondhjemite-granodiorite (TTG) series generated by multi-stage partial melting of mantle-derived hydrated basaltic crust. In the less-studied Bastar craton of central India, the distribution of Paleoarchean TTG domains and associated supracrustal rocks reveals discrete crustal blocks of the Sukma, Kapsi and Kondagaon terranes. To test whether these terranes record distinct petrogenetic processes, we integrated whole-rock geochemical data and Nd isotopic compositions from representative TTG suites. The Sukma orthogneisses were formed by high-pressure partial melting of mafic rocks and tonalites in equilibrium with rutile-bearing eclogite residues, followed by plagioclase fractionation. Their ε_Nd(3.5Ga) values (−10.9 to +1.1; median − 5.1) and crustal residence times (∼0.5 Ga) indicate reworking of Hadean-Eoarchean crust with juvenile input. The Kapsi TTGs were derived from medium-pressure partial melting of mafic rocks in equilibrium with garnet-amphibolite residues and evolved through plagioclase–amphibole fractionation. Their ε_Nd(3.5Ga) values (−10.5 to +1.0; median − 3.9) and crustal residence times (∼0.4 Ga) indicate reworking of Hadean-Eoarchean crust. The K-rich Kondagaon gneisses were formed by low-pressure partial melting of tonalites, in equilibrium with rutile-free eclogite and garnet-amphibolite residues and evolved through plagioclase fractionation. Their ε_Nd(3.2Ga) values (−7.0 to +2.9; median + 1.0) and short residence times (∼0.1 Ga) indicate that their melts were derived mainly from juvenile sources with limited crustal input. Widespread emplacement of the Kanker Granite at 2986 ± 37 Ma (zircon ε_Hf(t) = −3.7 and whole-rock ε_Nd(t) = −0.5 to −6.7) is linked to terrane amalgamation during the ∼3.0 Ga Sukma orogeny. Although early Archean TTG terranes formed by distinct petrogenetic processes, their amalgamation since the Mesoarchean resulted in the growth and stabilization of Archean cratons.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108377"},"PeriodicalIF":2.5,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880768","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":"Geochronology and geochemistry of the Yalong skarn Fe polymetallic mineralization occurrence in the Bangong-Nujiang metallogenic belt, China","authors":"Yunlong He ,&nbsp;Jianhua Zhou ,&nbsp;Liqiang Wang ,&nbsp;Baoliang Li ,&nbsp;Teng Gao ,&nbsp;Yong Wang ,&nbsp;Yifei He","doi":"10.1016/j.lithos.2025.108394","DOIUrl":"10.1016/j.lithos.2025.108394","url":null,"abstract":"<div><div>The Yalong Fe-Cu-Mo mineralization occurrence, newly discovered in the western part of the Bangong-Nujiang metallogenic belt, is related to the granodiorite. The skarn Fe<img>Cu mineralization is hosted in the contact zones between the granodiorite and limestone of the Riganpeicuo Group, whereas the Mo mineralization occurs within the granodiorite. Zircon U<img>Pb dating of the ore-forming granodiorite and molybdenite <em>Re</em><img>Os dating yield ages of 158.1 Ma and 153.7 Ma, respectively. These results show that the mineralization occurred during the Late Jurassic. In addition to the granodiorite, the monzogranite and K-feldspar granite are also developed in the mining area. All these intrusions are high-K calc-alkaline and I-type granitoids. They are enriched in LREEs and LILEs and depleted in HREEs and HFSEs, showing similarities with arc magmas. The negative zircon <em>ε</em>_Hf(t) values (mostly between −4.31 and − 1.1) and ancient two-stage model ages (mostly between 1482 and 1277 Ma) indicate that the Yalong intrusions were mainly derived from partial melting of ancient crust. Rhenium contents of molybdenite (0.09 to 1.26 ppm) and H<img>O isotopic compositions (δD = −73.3 to −68.1 ‰; <em>δ</em>¹⁸O_H2O = 10.8 to 12.1 ‰) of garnet show that the ore-forming metals and fluids were sourced from the granodiorite. The Yalong intrusions have similar formation ages and geochemical characteristics to those of the ore-forming intrusions associated with other skarn Fe polymetallic deposits in the western part of the Southern Qiangtang terrane. Accordingly, this study proposes that the Yalong Fe-Cu-Mo mineralization was formed in the continental margin arc setting associated with the northward subduction of the Bangong-Nujiang Tethyan Ocean. However, the low oxygen fugacity and water content, the lack of mantle-derived materials, and the high evolution degree of the Yalong intrusions indicate that the skarn Fe-Cu-Mo mineralization potential is limited.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108394"},"PeriodicalIF":2.5,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880723","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 importance of considering temperature- and composition-dependent partition coefficients in differentiation models","authors":"Aurore Toussaint ,&nbsp;Lydéric France","doi":"10.1016/j.lithos.2025.108395","DOIUrl":"10.1016/j.lithos.2025.108395","url":null,"abstract":"<div><div>Quantifying the parameters that govern magma differentiation is key to understanding the evolution of igneous systems<em>.</em> We present an approach combining thermodynamic modeling of magma differentiation using Rhyolite-MELTS with chemical composition, temperature, pressure, and oxygen fugacity (<em>X</em>-<em>T</em>-<em>P</em>-<em>f</em>O₂)-dependent partition coefficients (<em>D</em>) for rare earth elements. We apply this approach to a MORB system containing olivine, plagioclase, and clinopyroxene as the main mineral assemblage and compare the results to more classic approaches typically considering fixed <em>D</em> values. Our model highlights that the effects of temperature and composition on <em>D</em> values can compound or counteract each other depending on the mineral and element considered. Our results emphasize the value of using thermodynamic models alongside <em>T</em>-<em>X</em>-dependent <em>D</em> values to properly model the evolution of igneous systems. We show that this is of particular interest for modeling the evolution of rare earth element contents in minerals during differentiation. Using our results and corresponding thermodynamic constraints, we can provide <em>D</em> values for any mineral composition crystallized from this MORB system; based on chemical maps, we use our results to derive unprecedented maps of <em>D</em> values, highlighting strong partitioning variability at the thin-section scale. Therefore, using fixed <em>D</em> values can introduce significant mineral-melt partitioning errors compared to using <em>T-X</em>-dependent values, potentially leading to serious interpretation biases.</div></div>","PeriodicalId":18070,"journal":{"name":"Lithos","volume":"522 ","pages":"Article 108395"},"PeriodicalIF":2.5,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880766","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}