Tourmaline is a reliable recorder of magmatic-hydrothermal evolution and ore mineralization. Numerous investigations on tourmaline from magmatic rocks and ore deposits have been conducted, while the links between tourmaline and granite-related uranium (U) mineralization systems remain poorly understood. This paper presents data of in-situ major and trace elemental compositions of tourmaline in the U-bearing and U-barren granitic plutons from the Xiazhuang U orefield by EPMA and LA-ICP-MS. Four types of tourmalines are identified by occurrences: (1) disseminated tourmaline (D-T) in the U-barren Luxi pluton; (2) interstitial tourmaline (I-T) in the U-bearing Maofeng pluton; (3) segregational tourmaline (S-T) in the U-bearing Xiazhuang pluton and (4) tourmaline veins (V-T) (including samples from the Zhushanxia U deposit (VZ-T), the Xiwang U deposit (VX-T) and the Luxi pluton (VL-T)). Tourmaline grains from the U deposits all display "cracked" appearance under the microscope, whereas those from the U-barren area remain intact. All the tourmalines are rich in Al (>6 apfu), and belong to the alkali group and schorl endmember, falling into field 2 in the total Al-Fe-Mg ternary diagram. Petrographic and chemical composition data suggest that the D-T was primary magmatic in origin and formed in a late stage from the fractionated magma; the I-T and the S-T crystallized during the magmatic-hydrothermal transition; the V-T formed in magmatic hydrothermal fluids that may have been interacted with country rocks. The negative correlation of Fe and Mg from the D-T to the V-T demonstrates the MgFe_1 exchange vector, suggesting constant reduced crystallization environments from magmatic to hydrothermal fluids. Concentrations of V, Sr, Sc, Nb, Ta, and Mg/(Mg + Fe) ratios in tourmaline exhibit marked differences between the D-T and the V-T, and are considered as efficient discriminators for the magmatic and hydrothermal tourmaline. The gradually elevated contents of Sr and Mg/(Mg + Fe) ratios from the D-T, I-T to the S-T perfectly monitors fluid evolution from magmatic to magmatic-hydrothermal transition. The VZ-T and the VX-T from the U deposits show pronounced higher concentrations of Pb (>10 +/- 2 ppm) and lower Sn/Pb ratios (<10 +/- 1). The high anomaly of Pb in the hydrothermal tourmaline from the U-rich granites reflects accumulations of Pb in the magmatic hydrothermal fluids possibly through radioactive decay of U from the fertile granitic melts. The unique "cracked" appearance of the tourmaline in the U deposits is attributed to the alkaline hydrothermal alteration associated with U remobilization, which in turn may provide another sign for U-bearing fluid activity and the process of U enrichment at Xiazhuang. The "cracked" texture and Pb contents of tourmaline can serve as powerful and costeffective vectoring tools for uranium exploration in similar granite-related systems globally.

The South China Block (SCB) is recognized as one of the most significant uranium deposit clusters in the world, characterized by its complex genetic types and geodynamic drives. Based on host rocks, uranium deposits in the SCB can be categorized into three primary types, exhibiting a trend from black shalerelated deposits in the west, to granite-related, and ultimately to volcanic-related deposits toward the eastern margin of the SCB. We identify that three types of deposits are primarily distributed within or along margins of ancient crustal domains. Geochronological data reveals large-scale uranium mineralization occurred predominantly during Cretaceous and Paleogene periods. Uranium mineralization was mainly controlled by structures in the extensional setting, developed particularly at subsidiary faults, lithological (unconformity, intrusion contacts) and physicochemical interfaces. Uranium mineralization is dominantly characterized by medium to low ore-forming temperature with pitchblende as the main industrial mineral, and with silicification, carbonatization, hematitization, fluoritization and chloritization as common alteration. Isotopic studies show that sulfur sourced from host rocks, while carbon isotopes distinguish mantle-derived signatures in granite- and volcanic-related deposits from primarily sedimentary organic matter sources in black shale-related deposit. Uranium was mainly contributed by host rocks which are relatively U-fertile geological formations. Magmatic and/or mantle-derived mineralizing agents promote the activation and migration of uranium in host rocks, and accelerate the accumulation of U in ore-forming fluids. Our study suggests that the coupling of shallow and deep-seated energy and conduit system within a crustal extension setting, together with the pre-enrichment of uranium in basement and host rocks, controlled the formation of uranium deposits in the SCB. (c) 2025 China University of Geosciences (Beijing) and Peking University. Published by Elsevier B.V. on behalf of China University of Geosciences (Beijing). Thi s is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Surficial uranium mineralization in central Jordan was investigated using an integrated trench-scale study approach that combines geological observations with petrographic, mineralogical, and whole-rock geochemical analyses from the Siwaqa North (SN) and Khan Al-Zabib (KZ) prospects. Uranium mineralization is hosted by carbonate-dominated sediments of the Muwaqqar Chalk Marl (MCM) Formation and occurs as shallow, stratabound zones preferentially developed at the saprolite–MCM interface. Whole-rock geochemical data indicate a uniformly carbonate-rich host in which uranium enrichment is commonly associated with P₂O₅-bearing intervals, whereas CaO, Fe₂O₃, and SiO₂ show no systematic control. Elevated U/Th ratios are further consistent with secondary uranium enrichment and near-surface uranium remobilization processes. X-ray diffraction patterns are dominated by calcite and show no discrete uranium-bearing phases, consistent with uranium occurring predominantly in adsorbed, amorphous, or poorly crystalline forms associated with reactive phosphate- and clay-bearing carbonate matrices. Comparison with previously published gamma-ray anomaly data indicates that mineralized zones are spatially associated with major strike-slip faults, consistent with fault-controlled migration of oxidized near-surface fluids. However, uranium accumulation was governed primarily by low-temperature geochemical trapping at shallow lithological and permeability contrasts rather than by structural localization alone. These findings support a supergene model in which structurally controlled fluid transport and localized geochemical fixation operated as complementary, yet partially decoupled processes. By integrating trench-scale geological, mineralogical, and geochemical evidence with regional structural relationships, this study provides a process-based genetic framework and practical exploration criteria for identifying comparable surficial uranium systems in arid to semi-arid carbonate settings.

The Hailuoling Nb-Ta deposit in the Wuyi metallogenic belt of South China represents a typical granite-related rare-metal system that has recently been recognized to host associated Li mineralization. To constrain its metallogenic evolution, we integrate petrological, geochronological, and geochemical data. LA-ICP-MS U-Pb dating of monazite and columbite-tantalite indicates that the porphyritic biotite monzogranite crystallized at 147.2 +/- 1.9 Ma, whereas Nb-Ta mineralization occurred at 144.4 +/- 2.1 Ma, both during the Late Jurassic-Early Cretaceous transition. Li-bearing micas including protolithionite, zinnwaldite, lithium phengite, and lithium muscovite, in mineralized granite replace primary biotite, feldspar, and quartz and display irregular grain boundaries and well-developed compositional zoning, providing textural evidence for hydrothermal metasomatism. Mica compositions define a systematic evolutionary trend characterized by increasing SiO2 and decreasing FeO contents, while trace element data reveal an initial enrichment followed by depletion of Li, Nb, and Ta. These features support a two-stage model involving an early post-magmatic hydrothermalism stage followed by a later hydrothermal metasomatism stage. Hydrothermal micas are characterized by Nb/Ta ratios of 0.5-2.5 and K/Rb ratios of 8-12. Comparative analyses with micas from unmineralized granites and from the Maoping and Xianghualing deposits highlights the necessity of overprinting by late-stage magmatic-hydrothermal fluids, in combination with external fluid input, to achieve economically significant rare-metal enrichment in early intrusions that did not independently reach ore-forming thresholds. We conclude that the interplay between magmatic differentiation and hydrothermal overprinting is critical for the mobilization and concentration of rare metals in certain granitic systems.

The Guidong complex in northern Guangdong constitutes a key segment of the Nanling Metallogenic Belt and hosts significant granite-related uranium deposits. However, the petrogenesis of the Yanshanian intrusions in its western part remains poorly constrained because of insufficient high-precision geochronological and mineralogical data. This limitation hinders a comprehensive understanding of regional metallogenesis. To address this, we conducted an integrated study of the Siqian two-mica granite and the Changping biotite granite, incorporating zircon U–Pb geochronology, whole-rock geochemistry, Hf–Nd isotope analysis, and mineral chemistry. Our objectives were to determine their emplacement ages and to investigate their petrogenesis and relationship with uranium mineralization. Zircon U–Pb dating indicates that the Siqian and Changping granites formed at 160 ± 1 Ma and 156 ± 1 Ma, respectively, suggesting both were emplaced during the Early Yanshanian magmatic event. These high-K calc-alkaline rocks are peraluminous (A/CNK = 1.04–1.44), enriched in large-ion lithophile elements (LILEs; e.g., Rb, Th, U), and depleted in high-field-strength elements (HFSEs; e.g., Ba, Nb, Ta). They exhibit negative zircon εHf(t) values ranging from – 15.4 to – 8.4, with corresponding crustal model ages of 1668–2142 Ma. Whole-rock samples show εNd(t) values from –11.2 to –9.1 and Nd model ages of 1693–1860 Ma. These isotopic features indicate that both plutons represent moderately differentiated S-type granites derived from partial melting of Paleo- to Mesoproterozoic metasedimentary sources (e.g., pelitic and psammitic rocks), accompanied by fractional crystallization of minerals such as ilmenite and apatite. Integrated geochemical and mineralogical data reveal that the Siqian and Changping granites are characterized by low Th/U ratios, high F contents, and low magmatic oxygen fugacity—signatures typical of U-rich granites. These attributes provided a favorable lithogeochemical environment for uranium enrichment and acted as primary sources for uranium-bearing, high-temperature hydrothermal fluids, thereby playing a critical role in regional uranium mineralization.

The western Tian Shan in Uzbekistan, forming the orogen's western terminus, provides critical insights into Meso-Cenozoic tectonic evolution through its uplift-exhumation history. This study integrates apatite/zircon fission-track (AFT/ZFT) and zircon (U-Th)/He analyses on 15 granitic samples from the Kyzylkum Nurata segment. Key findings include: (1) AFT ages span 67.50 f 10.03-215.31 f 14.53 Ma, with short mean track lengths (11.47 f 1.38-12.65 f 0.75 mu m), indicating partial thermal resetting.(2)The western Tian Shan experienced Meso-Cenozoic multi-phase rapid uplift-exhumation, revealing a progressive northwest-to-southeast younging of apatite fission track ages and a marked contrast in exhumation regimes between the northwestern Nurata Range and adjacent ranges within the Kyzylkum-Nurata segment, highlighting spatiotemporal migration of tectonic activity and localized deformation partitioning. (3) Three thermo-tectonic phases were identified: Triassic rapid exhumation responding to Turan-Qiangtang/Paleo-Asia collision; Jurassic-Early Cretaceous uplift controlled by Lhasa-Qiangtang collision effects; Late Cretaceous-Cenozoic burial-rejuvenation cycles linked to Kohistan-Dras arc accretion in the Late Cretaceous and India-Eurasia/Kunlun-Pamir collisions in the Cenozoic. Differential exhumation patterns reflect inherited crustal heterogeneity, suture zone reactivation, and far-field stresses from Tethyan plate interactions. This study fills critical gaps in understanding Meso-Cenozoic uplift-exhumation processes in the westernmost Tian Shan, providing enhanced constraining models for the tectonic evolution of the entire orogen. Based on the investigation into the dynamic origins of uplift and exhumation, it can be concluded that the trend of uplift and exhumation in the Kyzylkum-Nurata segment of the Western Tian Shan propagated from southeast to northwest.

The central Jiangnan orogenic belt in South China harbors a world-class magmatic-hydrothermal mineralization cluster, encompassing supergiant resources of tungsten (W), lithium (Li), copper (Cu), antimony (Sb), and gold (Au). This review synthesizes geological, geochemical, and geochronological data from key deposits to delineate two genetically distinct mineralization series: (1) A Cu-Au-W series associated with I- to S-type porphyry systems, characterized by potassic alteration and silicification; (2) An Nb-Ta-Li-W-Sn-Cu series linked to the evolution of S- to A-type granites, marked by sodic alteration, fluorine-rich muscovitization, and silicification. We propose a unified metallogenic model in which prolonged and episodic magmatism served dual roles: (i) as the source of granite-related rare metal and tungsten mineralization, and (ii) as the thermal engine driving regional hydrothermal circulation. This circulation leached Sb, U, and Au from Precambrian sedimentary sequences, re-precipitating them in structurally controlled sites as intermediate- to low-temperature vein-type deposits. The formation of these diverse yet genetically related deposits is interpreted as the result of extensive crustal magmatism within a unique extensional tectonic regime. This model provides a robust framework for future mineral exploration targeting in this metallogenic belt.

Pegmatite-type lithium (Li) deposits are a crucial source for modern batteries, yet their formation remains contentious due to limited understanding of their timing and processes. The existence of Indosinian lithium mineralization in the Altun region and the mechanisms of lithium migration and enrichment during magmatic-hydrothermal processes are particularly debated. The Kumusayi Li deposit, situated in biotite schist with muscovitization and greisenization halos around ore veins, provides significant insights. U-Pb dating of cassiterite (219.7 ± 5.2 Ma) from Kumusayi spodumene-bearing pegmatites confirms an Indosinian mineralization age. In-situ Rb-Sr isotopic analysis of micas reveals two metallogenic episodes: recorded by magmatic-hydrothermal muscovite P1 (206.8 ± 1.9 Ma) and hydrothermal muscovite H1 (196.2 ± 7.1 Ma). Microanalytical data of mica generations reveal a systematic geochemical evolution: Nb-W-Sn-Ta contents increase from P1 to H1-H3, while Li-Rb-Co-Ni decrease, with peak concentrations in H1 (Li2O = 1.8–2.3%). Altered biotite schist shows significant lithium depletion (primary biotite: Li2O = 0.18–0.25% vs. Re-equilibrated biotite: 0.03–0.06%), indicating substantial lithium mobilization during hydrothermal alteration. The metallogenic process comprises three stages: early magmatic crystallization of spodumene depletes lithium; late magmatic formation of lower-Li muscovite P1 (Li2O = 0.83–1.33%); and hydrothermal overprinting, where Li-enriched fluids precipitate high-Li muscovite H1, followed by progressive lithium depletion through H2-H4 (Li2O = 0.08–0.15%). This magmatic-hydrothermal mechanism is appears to be essential for Li enrichment leading to Li mineralization. Recognizing Indosinian lithium mineralization at Kumusayi and understanding lithium recycling between magmatic and hydrothermal systems offers new genetic models and exploration strategies for rare-metal deposits in the Altun belt. Notably, lithium replenishment from country rocks during hydrothermal alteration provides a novel perspective for regional prospecting.

The Xiazhuang uranium ore field in South China is a large-scale granite-type uranium ore field, yet the role of fault structures in controlling uranium mineralization remains controversial. Based on detailed field observations of fault striations (n > 250) and conjugate joints (n = 6), this study analyzes the multi-stage evolution of three fault sets (NWW, NNE, NEE) and inverts the Meso-Cenozoic tectonic stress field using Wulff net projection, to discuss how changes in mechanical properties control mineralization. It is inferred that the NWW-trending faults formed earliest and experienced multiple mechanical transitions. The NNE-trending faults controlled hydrothermal activity, evolving from compression to extension (during mineralization) to transtensional strike-slip. The NEE-trending faults controlled magmatic emplacement and post-mineralization uplift. The tectonic stress field evolution is divided into three periods and eight episodes: two pre-mineralization, four syn-mineralization, and two post-mineralization stages. The NWW-trending structural zone controlled early-stage mineralization, whereas the NNE- and NEE-trending fault zones controlled late-stage mineralization. Local superposition of these episodes forms rich orebodies. A tectonic stress field-mineralization model is constructed to guide regional exploration.

Jiangxi Province, situated in the hinterland of the South China Block, spans the Yangtze Block, the Jiangnan Orogenic Belt, and the Cathaysia Block. It encompasses five major metallogenic belts: the Middle-Lower Yangtze River, Jiangnan, Qin-Hang, Wuyishan, and Nanling regions, establishing it as a significant province of mineral resources in China. Through systematic investigation of the regional geological evolution, geophysical field anomalies, structural deformation, geochemical compositions of ore-forming rock bodies, and the spatio-temporal distribution of mineralization, this study elucidates the regional metallogenic mechanisms and key controlling factors, and proposes criteria for mineral prediction. The study area experienced Proteruzoic amalgamation of multiple terranes, the deposition of Proterozoic W-rich clastic rocks and Cambrian U-V-rich black shales, overprinted by the Caledonian, Indosinian, and Yanshanian multistage orogenic-magmatic evolution. Mesozoic large-scale crust-mantle interaction triggered a major mineralization event in the region. Six major deposit series are identified in Jiangxi, including: (hydrothermal-) sedimentary V-Mn deposits, granite-related W-Li-Nb-Ta polymetallic deposits, granite porphyry-volcanic rock-related Cu-Au-Ag-Pb-Zn deposits, shesar zone-controlled orogenic An deposits, hydrothermal remobilization-related U deposits, and weathering crust-hosted ion-adsorption REE deposits. Composite orogenesis controlled the multi-stage mineralization: Sedimentary deposits and metal-enriched basements formed during Proterozoic; Mesozoic melting of this basement generated intermediate-acid rocks associated with Cu-Au-Ag-Pb-Zn and W-Sn-Li-Nh-Ta deposits; post-Late Cretaceous crustal extension and uplift, basin fluid circulation, and supergene weathering formed hydrothermal remobilization-type U deposits and weathering crest-hosted ion-adsorption REE deposits. Multi-stage orogenesis induced repeated crustal melting, facilitating the progressive extraction and enrichment of metals, thereby enhancing the metallogenic potential of later magmas. Composite structures controlled ore body emplacement, and differential uplift led to the juxtaposition of deposits formed at different crustal levels near the surface. Three main phases of large-scale Mesozoic mineralization occurred during a period of plate rotation and regional tectonic activation; the ca. 175-160Ma Dexing Cu-Au and Lengshuikeng Ag-Ph-Zn deposits, the ca 160 -150Ma southern Jiangxi W-Sn-Nb-Ta deposits, and the ca. 150-140 Ma Jiangnan Orogenic Belt W-Li-Nb-Ta deposits. The spatio temporal migration of the compressional-extensional transition controlled the clockwise evolutionary trend of these mineralization events. The Mesozoic Cu-An-Ag-Pb-Zn deposits are associated with granitic porphyries and volcanic rocks, with lithologies including granodiorite and diorite porphyry, which are metaluminous to weakly peraluminous, with a mixed crust-mantle source (highly variable (1)), linked to the activation of juvenile crust. The granite-related W-Sn deposits are associated with biotite granite and two-mica granite, which are peraluminous to strongly peraluminous, exhibiting a clear crustal source affinity (low 2(1)) derived from reworked crust subjected to multiple melting events. The magmatic rocks at the Nb-Ta-Li deposits show even more pronounced high differentiation, with lithologies consisting of strongly albitized muscovite granite, which is strongly peraluminous. The study proposes a three-stage evolution for the fertile intermediate-acid intrusions; deep crystal mush reactivation, shallow crustal differentiation, and top-pulse melt extraction. This research reveals that the formation of Jiangxi's globally significant giant polymetallic mineral resource base was comprehensively controlled by several factors: early multi-terrane amalgamation and crustal multicomponent architecture; Yanshanian crust-mantle interaction and multiple compressional-extensional transitions; the differential sources of juvenile versus reworked crust and resulting granite metallogenic specialization; multi-stage extraction of crustal materials during composite orogenesis; lectonic complexity controlling, melt-fluid focusing; the staged enrichment of W-Li-Nb-Ta in magmatic-hydrothermal systems; and late stage differential uplift leading to the near-surface coexistence of deep, mid, and shallow-level deposits. Metallogenic prediction should integrate information on magmatic metallogenic specialization, multi-stage metal enrichment in lithofacies, multi-scale structural complexes and transition zones, alteration assemblages, and indicator minerals such as mica.

Tungsten (W), lithium (Li), and other rare metals are essential components in various industries. The coexistence of tungsten and lithium deposits represents a deposit type with great economic potential. However, the process of W-Li co-mineralization remains poorly understood, presenting challenges in elucidating the mechanisms governing their concurrent presence. This study focuses on the Gaoaobei tungsten (W) deposit, notable for its substantial lithium (Li) content, classifying it as a greisen-type W-Li deposit. Specifically, what is the process of Li enrichment and mineralization within tungsten deposits, and which factors play a critical role in controlling the occurrence of Li mineralization events in tungsten deposits. The monazite U-Pb dating indicates that the medium-coarse-grained biotite monzogranite in the Gaoaobei deposit formed at 226.3 f 1.9 Ma, while the medium-grained muscovite granite was dated at 160.0 f 1.4 Ma. The cassiterite U-Pb ages of results for the medium-coarse-grained biotite granite (wall rock), medium-grained muscovite granite (metallogenic granite), and aplite indicate that the hydrothermal stage Li mineralization in the Gaoaobei W-Li deposit ranges from approximately 159.0 f 4.6 Ma to 155.3 f 4.5 Ma. The Gaoaobei W-Li deposit is characterized by early-stage alterations, including biotitization, albitization, and muscovitization, followed by late-stage silicification and sericitization. The study reveals that the mica types in the Gaoaobei W-Li deposit are predominant Zinnwaldite, Protolithionite, and Lepidolite, characterized by high Al and Fe contents and low Ti, Ca contents, among other features. The mineral compositions of various mica types demonstrate an evolutionary trend from early to late stages, showing an increase in Li, Rb, Ta, and Zn contents, and a decrease in W, Sn, and Nb contents. The magmatic muscovite exhibits Nb/Ta ratios mostly exceeding 4 and Li/Rb ratios mostly below 1.5. In contrast, hydrothermal muscovite displays lower Nb/Ta ratios (mostly below 4) but higher Li/Rb ratios (mostly above 1.5). Re-equilibrated muscovite falls within the intermediate range of these two categories (Nb/Ta = 0 to 4; Li/ Rb = 0.1 to 2), highlighting that a Li/Rb ratio greater than 1.5 can serve as a criterion for evaluating the potential for Li mineralization. The majority of Zr/Hf ratios of muscovite in the Gaoaobei deposit are below 10, suggesting promising prospects for W, Sn, Mo, and other deposits. This study establishes the initial determination of the granite-forming ages for the Yanshanian period granite in the Gaoaobei mining area and links the hydrothermal stage Li mineralization age of the Gaoaobei deposit to the Late Jurassic large-scale W-Sn mineralization event in the Nanling Range. These findings provide valuable insights for the exploration of rare metal deposits such as Li in W mines in the Nanling Range and similar deposits worldwide.

The Tong’an-Baishuidong mining district (TBMD), located in the eastern section of the Jiangnan Orogen, is a newly discovered granite-type lithium mining district. Thisstudy presents new monazite U–Pb chronological, whole-rock geochemical, and Nd–Pb isotopic data to reveal the petrogenesis and geodynamic setting of the Wutang granites in the TBMD. The monazite U–Pb age of 145.8 ± 1.0 Ma indicates that the granites were emplaced at the end of the Late Jurassic. Whole-rock geochemical results demonstrate that the Wutang granites are enriched in SiO2 (72.80–73.40 wt

The Sandaocha lode gold deposit is a representative example of the Jiapigou Ore District (JOD), located at the northeastern edge of the North China Craton. The orebodies are composed of auriferous polymetallic sulfide-quartz veins hosted within Neoarchean to early Paleoproterozoic metamorphosed intrusions and supracrustal rocks, and are governed by NNE-striking ductile-brittle secondary faults. Mineralogical assemblages and crosscutting relationships reveal that the deposit formed through three mineralization stages: (I) arsenopyrite-pyrite-quartz, (II) gold-polymetallic sulfide-quartz, and (III) carbonate-quartz. The Re-Os isochron age of 239 +/- 3 Ma (MSWD = 1.5), obtained from six pyrite samples of stage II, constrains the Sandaocha gold mineralization to the Middle Triassic and reveals the oldest-known gold-forming event in the JOD. Geological, chronological, and H-O isotopic results indicate that the Sandaocha gold mineralization has close temporal-spatial and genetic links with coeval magmatic-hydrothermal event. Moreover, chronological data from this and previous studies indicates that the JOD underwent at least three distinct periods of gold mineralization. The ca. 239-204 Ma gold-forming event occurred during the extensional period following the Paleo-Asian Ocean closure, the ca. 178-170 Ma gold-forming event occurred in a compression-extension transitional setting towards the end of Paleo-Pacific Plate subduction, and the ca. 156-152 Ma gold-forming event was associated with the post-subduction extensional setting.

[Objective]The Qinling Orogenic Belt,positioned between the Yangtze and North China cratons,has undergone a multi-stage evolution from the Paleozoic to the Early Mesozoic,fully documenting the collisional orogenic history between both cratons.Substantial research achievements have been accumulated in fields such as provenance,lithogeochemistry,magmatic activity,and tectonics.However,key issues regarding the Early Paleozoic tectonic framework and Late Paleozoic ocean basin evolution of the Qinling Orogenic Belt remain controversial,primarily including the following aspects:The Shangdan Ocean may have closed during the Early Silurian,Carboniferous,or Indosinian periods;the subduction of the Mianlue Ocean may have initiated in the Early Carboniferous,Late Permian,end of the Late Permian,or later than the Early Triassic.The Zhaishang area in Minxian County,located within the Western Qinling Orogenic Belt,shows extensive Paleozoic strata and serves as a critical window for studying the tectonic evolution history of the Qinling Orogenic Belt.[Methods]Systematic sampling was conducted on the exposed Devonian,Carboniferous,and Permian strata in this area.The procedures included zircon single-mineral separation,target preparation,polishing,and cathodoluminescence(CL)imaging,followed by zircon U-Pb isotope analysis using LA-ICP-MS(Laser Ablation Inductively Coupled Plasma Mass Spectrometry).Based on these experimental results,detrital zircon U-Pb chronology was performed for the Devonian,Carboniferous,and Permian strata exposed in the Zhaishang area of Minxian County,Western Qinling,to constrain the Paleozoic tectonic evolution history and sedimentary processes of the Qinling Orogenic Belt.[Results]Results of detrital zircon U-Pb chronology show that the Shuanglanggou Formation of the Xihan Shui Group and the Badu Formation in the Zhaishang area of Minxian County exhibit similar detrital zircon age compositions.Detrital zircons from the Shuanglanggou Formation(Devonian Xihanshui Group)are characterized by the dominant age peak at 794 Ma,belonging to a Neoproterozoic age group(880～746 Ma),and the youngest age peak at 448 Ma.Detrital zircons from the Lower Carboniferous Badu Formation display Neoproterozoic age groups(901～750 Ma),the dominant age peak at 818 Ma,and the youngest age peak at 390 Ma.Detrital zircons from the middle member of the Lower Permian Shilidun Formation exhibit the dominant and likewise youngest age peak at 443 Ma,belonging to an Early Paleozoic age group(464～409 Ma).[Conclusion]Through comparing the relative probability distribution curves of detrital zircon U-Pb ages of the Devonian,Carboniferous,and Permian strata,as well as the correlation diagrams between detrital zircon age peaks and tectonic settings(including the northern Qinling Orogenic Belt,North China Craton,and Yangtze Craton as comparison targets),it is revealed that:The Devonian Shuanglanggou Formation and the Carboniferous Badu Formation in the Zhaishang area share a consistent detrital provenance,primarily the Yangtze Craton,followed by the northern Qinling Orogenic Belt;both tectonic settings are classified as rift basins.The detrital materials of the middle member of the Permian Shilidun Formation stem predominantly from the northern Qinling Orogenic Belt and correspond to a back-arc basin tectonic setting.By integrating the research results with the relative positions of the Qinling Orogenic Belt,the North China Craton,the Yangtze Craton,the Shangdan Ocean,and the Mianlue Ocean,it is concluded that the Zhaishang area in Minxian County was in a rift basin environment from the Late Devonian to the Early Carboniferous,and transitioned to a back-arc basin in the Early Permian.This transition marks the completion of the Mianlue Ocean's evolution from oceanic expansion to subduction and demise.Additionally,the study constrains that:The Mianlue Ocean opened after the Early Carboniferous;the Shangdan Ocean closed before the Late Devonian.[Significance]This study provides new evidence and chronological constraints for the tectonic evolution of the Qinling Orogenic Belt,as well as the closure time of the Shangdan Ocean and the initial subduction time of the Mianlue Ocean,helping to reconstruct and restore the tectonic evolution process of the Qinling Orogenic Belt.

The Xiazhuang uranium ore field, situated on the southeastern side of the Guidong complex in northern Guangdong Province, is an important hard rock uranium resource bases in southern China. In this study, petrography, mineral thermobarometry, and apatite fission track (AFT) methods were used to study the genetic mineralogy and uplift-erosion history of various granites in the mining area. The Donggualing body is characterized by high temperature and pressure, medium to high oxygen fugacity, high water content, and alkalinity, with characteristics typical of a subduction zone supply. The biotite chemistry indicates that the Indosinian bodies have high Mg, low temperature, low oxygen fugacity, and peraluminous characteristics, whereas the Yanshanian bodies are calc-alkaline peraluminous granites of crustal origin. Estimates of emplacement depth suggest that biotite barometry may be more reliable than hornblende barometry, with the Caledonian Donggualing body emplaced at a depth of 11.9 km; the Indosinian Xiazhuang, Luxi, and Shituling bodies at an average depth of 14.5 km; and the Yanshanian Taoshuba, Shishitou, and Zhutongjian bodies at an average depth of 6.8 km. AFT and thermal history modeling showed that the uplift of the Indosinian bodies began earlier than that of the Yanshanian bodies, indicating that the Mesozoic-Cenozoic uplift process in the Guidong area expanded from east to west. Based on the physicochemical conditions of diagenesis, AFT thermal history modeling, and previous studies on diagenesis, mineralization ages, fluid inclusions, and deposits, the high U, rich F, low oxygen fugacity, and peraluminous characteristics of the Indosinian bodies are shown to have significantly controlled U enrichment. The natural absence or severe erosion of Indosinian bodies on the western side of the Guidong complex severely affects the spatial distribution of regional deposits. Furthermore, the combined control of the Huangpi and Mashishanshan faults is a key factor in the preservation of orebodies in the Xiazhuang uranium ore field. The deeper part of this area has better potential for mineral exploration than the western part of the Guidong complex.

The Tarim Large Igneous Province (TLIP) in NW China hosts abundant Fe–Ti–V oxide deposits associated with mafic–ultramafic intrusions. In the Xiahenan area, on the western margin of the TLIP, a distinct magnetic anomaly is linked to widespread surface accumulations of black sand. However, the genesis and origin of these black sand grains remain unclear. Based on mineral assemblages, this study classifies the grains of the black sand into three types: (i) plagioclase (An10–90)–ilmenite–olivine–magnetite assemblage (Sand I), (ii) plagioclase (An0–10)-fine-grained magnetite assemblage (Sand II), and (iii) hornblende–magnetite highly complex assemblage (Sand III). Mineral geochemical studies demonstrate that magnetite in Sand I and Sand II is of magmatic origin, with protolith being basaltic magma. Magnetite in Sand III was eroded from veins formed by hydrothermal processes at 300–500 °C. Ilmenite in Sand I contains a high FeTiO3 component, representing basaltic ilmenite. Olivine in Sand I has a low Fo content (43.86–47.27), belonging to hortonolite olivine. Research indicates that Sand I and Sand II share similar mineral assemblages and mineral geochemical characteristics with basalts in the Xiahenan area, suggesting they are weathering products of Xiahenan basalts or their cognate magmas. In contrast, the veined magnetite of Sand III formed during post-magmatic hydrothermal events.

Xiazhuang uranium ore field, located in the southern part of the Nanling Metallogenic Belt, is considered one of the largest granite-related U regions in South China. In this paper, we contribute new apatite fission track data and thermal history modeling to constrain the exhumation history and evaluate preservation potential of the Xiazhuang Uranium ore field. Nine Triassic outcrop granite samples collected from different locations of Xiazhuang Uranium ore field yield AFT ages ranging from 43 to 24 Ma with similar mean confined fission track lengths ranging from 11.8 ± 2.0 to 12.9 ± 1.9 μm and Dpar values between 1.01 and 1.51 μm. The robustness time-temperature reconstructions of samples from the hanging wall of Huangpi fault show that the Xiazhuang Uranium ore field experienced a time of monotonous and slow cooling starting from middle Paleocene to middle Miocene (∼60–10 Ma), followed by relatively rapid exhumation in the late Miocene (∼10–5 Ma) and nearly thermal stability in the Pliocene–Quaternary (∼5–0 Ma). The amount of exhumation after U mineralization since the Middle Paleogene was estimated as ∼4.3 ± 1.8 km according to the integrated thermal history model. Previous studies indicate that the ore-forming ages of U deposits in the Xiazhuang ore field are mainly before Middle Paleocene and the mineralization depths are more than 4.4 ± 1.2 km. Therefore, the exhumation history since middle Paleocene plays important roles in the preservation of the Xiazhuang Uranium ore field.

[ Objective ] Carbonatites, as magmatic-origin rocks, are crucial source rocks for uranium, rare earth, and other minerals. They are widely distributed in the Xiaoqinling region of Shaanxi, giving rise to numerous large to super-large carbonatite deposits of uranium, molybdenum, and rare earth, represented by Huayangchuan and Dashigou, attracting attention from scholars in recent years. Previous studies on carbonatite deposits in the area focused on petrology, mineralogy, genesis, and mineralization chronology. However, they were often limited to individual deposits, needing more regional cross-sectional comparative studies. [ Methods ] This study employs field geological surveys, petrographic analysis, and geochemical characterization of typical rocks and ores to reclassify different types and stages of Xiaoqinling carbonatites. It analyzes the geochemical characteristics of various carbonatite types and explores the mineralization processes of uranium and rare earth elements associated with carbonatites. [ Results ] Xiaoqinling carbonatites exhibit a large vein, vein group, and vein network morphology, intruding into the Archean metamorphic basement, Xiong'er Group volcanic sedimentary rocks of the Changchengian System, and Gaoshanhe Group clastic rocks of the Jixianian System along fault structures. Based on field crosscutting relationships and primary mineral assemblage characteristics, Xiaoqinling carbonate rocks can be re-divided into five stages from old to new: aegirine syenite stage (I), aegirine carbonatite stage (II), potassium feldspar carbonatite stage (III), quartz carbonatite stage (IV) and zeolite-bearing carbonatite stage (V). Spatially, the division is roughly along the nearly EW-striking Xiaohe Fault, with northern carbonatite veins dominated by aegirine syenite and aegirine carbonatite, rich in aegirine, biotite and other dark minerals, distributed in the Archean gneiss basement. The southern part is mainly composed of light-colored potassic feldspar carbonatites and quartz carbonatites, almost devoid of dark minerals, with surrounding rocks consisting of Xiong'er Group volcanic sedimentary rocks and Gaoshanhe group clastic rocks. Zeolite-bearing carbonatites are distributed throughout the region. Temporally, the carbonatites formed in the Late Triassic, but distinct temporal differences exist among different sections. Previous data indicate a possible 30 Ma gap in the formation times of various carbonatite types in the Xiaoqinling area. The geochemical characteristics of Xiaoqinling carbonatites reveal an average SiO2 content of 30.43%, significantly higher than the global average for carbonatites. CaO is relatively low, with an average content of 28.71%, exhibiting a clear negative correlation with SiO2 content. Total alkali (Na2O+K2O) content is relatively high, averaging 2.25%, with a maximum value of 10.23%. The total alkali content decreases gradually from early to late stages, strongly correlating with CaO and Al2O3 content. The potassium-sodium ratio (w(K2O)/w(Na2O)) is exceptionally high, with an average of 4.625 and a maximum value of 36.55. Ferromagnesian content (TFe2O3+MgO) varies significantly, with early-stage carbonatites (Stages I, II, III) having higher ferromagnesian content (average 8.29%), while late-stage carbonatites (Stages IV, V) generally have lower ferromagnesian content (average 1.92%). Ferromagnesian content correlates positively with TiO2 content. MnO has an average content of 1.22%, reaching up to 4.49%, notably enriched in late-stage quartz carbonatites. REE content averages 0.26%, with a maximum value of 0.96%, exhibiting a positive correlation with MgO content. The ∑LREE/∑HREE ratio ranges from 0.47 to 27.72, with early-stage carbonatites (Stages I, II, III) showing strong heavy REE depletion. Late-stage quartz carbonatites have an average ∑LREE/∑HREE ratio of 2.15, indicating relatively heavy REE enrichment, especially in Tm, Yb, Lu, and Y. Heavy REE content correlates linearly with MnO content. The overall REE distribution pattern of carbonatites is a steep-left and gentle-right, relatively flat-right-trending model, showing continuous variations in REE distribution patterns throughout different stages. Ore-related element content characteristics of various carbonatite types reveal significant U and Nb enrichment in aegirine syenite, aegirine carbonatite, and potassium feldspar carbonatite. Mo-mineralization is closely associated with potassium feldspar carbonatite and quartz carbonatite, while Pb and Ba-Sr mineralization is evident in all carbonatite stages. [ Conclusions ] (1) Xiaoqinling carbonatites are categorized into aegirine syenites, aegirine carbonatites, potassium feldspar carbonatites, quartz carbonatites, and zeolite-bearing carbonatites in chronological order. (2) Xiaoqinling carbonatites exhibit notably high SiO2 and total alkali content, low MgO content, and exceptionally high potassium-sodium ratio. There is a gradual decrease in CaO, TiO2, Al2O3, ferromagnesian, and total alkali content from early to late stages, while MnO content shows an opposite trend. Carbonatites evolve from early ferrocarbonatite to late calciocarbonatite. (3) Different types of carbonatites show distinct ore-related characteristics, with early stages (aegirine syenite, aegirine carbonatite, and potassium feldspar carbonatite) mainly enriched in U (Nb), and Potassic Feldspar Carbonate additionally enriched in Mo. Late-stage quartz carbonatites are characterized by Mo and HREE enrichment. [ Significance ] The findings of this study provide valuable information for the exploration and research of carbonatite-type uranium, rare earth, and polymetallic deposits in the Xiaoqinling area, holding significant practical importance.