The Saima deposit is a newly discovered niobium deposit which is located in the eastern of Liaoning Province, NE China. Its mineralization age and geochemical characteristics are firstly reported in this study. The Nb orebodies are hosted by the grey–brown to grass-green aegirine nepheline syenite. Detailed petrographical studies show that the syenite consists of orthoclase (~50%), nepheline (~30%), biotite (~15%) and minor arfvedsonite (~3%) and aegirine (~2%), with weak hydrothermal alteration dominated by silicification. In situ LA-ICP-MS zircon U-Pb dating indicates that the aegirine nepheline syenite was emplaced in the Late Triassic (229.5 ± 2.2 Ma), which is spatially, temporally and genetically related to Nb mineralization. These aegirine nepheline syenites have SiO₂ contents in the range of 55.86–63.80 wt. %, low TiO₂ contents of 0.36–0.64 wt. %, P₂O₅ contents of 0.04–0.11 wt. % and Al₂O₃ contents of more than 15 wt. %. They are characterized by relatively high (K₂O + Na₂O) values of 9.72–15.51 wt. %, K₂O/Na₂O ratios of 2.42–3.64 wt. % and Rittmann indexes (σ = [ω(K₂O + Na₂O)]²/[ω(SiO₂ − 43)]) of 6.84–17.10, belonging to the high-K peralkaline, metaluminous type. These syenites are enriched in large ion lithophile elements (LILEs, e.g., Cs, Rb and Ba) and light rare earth elements (LREEs) and relatively depleted in high field strength elements (HFSEs, e.g., Nb, Zr and Ti) and heavy rare earth elements (HREEs), with transitional elements showing an obvious W-shaped distribution pattern. Based on these geochronological and geochemical features, we propose that the ore-forming intrusion associated with the Nb mineralization was formed under post-collision continental-rift setting, which is consistent with the tectonic regime of post-collision between the North China Craton and Paleo-Asian oceanic plate during the age in Ma for Indosinian (257–205 Ma). Intensive magmatic and metallogenic events resulted from partial melting of lithospheric mantle occurred during the post-collisional rifting, resulting in the development of large-scale Cu–Mo mineralization and rare earth deposits in the eastern part of Liaoning Province.

The southwestern region of China is tectonically situated within the Tethyan tectonic domain, with the eastern part comprising the Upper Yangtze Block, while the western orogenic belt forms the main part of the Tibetan Plateau. This belt was formed by the subduction of the Paleo-Tethys Ocean and subsequent arc-continent collision, and was later further modified by the India-Asia collision, resulting in complex geological structures such as the Hengduan Mountains. The lithostratigraphy in this region can be divided into six independent units. In terms of mineralization, the area encompasses two first-order metallogenic domains: the Tethyan-Himalayan and the Circum-Pacific. This study synthesizes extensive previous research to systematically investigate representative rare earth element (REE) deposits (e.g., Muchuan and Maoniuping in Sichuan; the Xinhua deposit in Guizhou; the Lincang deposit in Yunnan). Through comparative analysis of regional tectonic-metallogenic settings, we demonstrate that REE distribution in Southwest China is fundamentally controlled by Tethyan tectonic evolution: sedimentary-weathered types dominate in the east, while orogenic magmatism-related types prevail in the west. These findings reveal critical metallogenic patterns, establishing a foundation for cross-regional resource assessment and exploration targeting. The region hosts 32 identified REE occurrences, predominantly light REE (LREE)-enriched, genetically classified as endogenic, exogenic, and metamorphic deposit types. Metallogenic epochs include Precambrian, Paleozoic, and Mesozoic-Cenozoic periods, with the latter being most REE-relevant. Six prospective exploration areas are delineated: Mianning-Dechang, Weining-Zhijin, Long’an, Simao Adebo, Shuiqiao, and the eastern Yunnan-western Guizhou sedimentary-type district. Notably, the discovery of paleo-weathering crust-sedimentary-clay type REE deposits in eastern Yunnan-western Guizhou significantly expands regional exploration potential, opening new avenues for future resource development.

The Shulan area in Jilin Province is a part of the Lesser Xing’an–Zhangguangcai Range polymetallic ore belt, which is an important Cu–Mo ore region of northeast China. The discovery of three large Mo ore deposits (Fu’anbu, Chang’anbu, and Jidetun) highlights its potential for porphyry Mo ore deposits. Here we investigated the tectonic setting and mineralization of Mo ore deposits in the Shulan area, based on comparative study of the Fu’anbu, Chang’anbu, and Jidetun deposits. The ore-controlling structures are NE–SW- and NW–SE-trending faults. The main ore mineral in all three deposits is molybdenite. The ore bodies are all hosted in granites, have a stratiform or lenticular shape, and have strongly altered wall rocks. These observations indicate the Mo deposits in the Shulan area are typical porphyry Mo deposits. All were formed during the early Yanshanian (199.6–133.9 Ma). Biotite adamellites from the Chang’anbu deposit yield a U–Pb age of 182.10 ± 1.20 Ma. Molybdenites from the Fu’anbu and Jidetun deposits have Re–Os isochron ages of 166.9 ± 6.7 and 169.1 ± 1.8 Ma, respectively. Quartz and ore minerals were analysed for H–O and S–Pb isotopes, respectively. The results suggest the ore-forming materials were predominantly of upper-mantle origin, with secondary contributions from the lower crust. The ore-hosting granites have high concentrations of SiO₂ (66.67–75.43 wt.%) and Al₂O₃ (12.91–16.44 wt.%), low concentrations of MgO (0.09–1.54 wt.%), and Ritman index (σ = K₂O + Na₂O)²/(SiO₂ − 43)) ratios of 2.09–2.57. The granites are enriched in large-ion lithophile elements and depleted in high-field-strength elements, and have negative Eu anomalies. The ore-hosting rocks are geochemically similar to granites in northeastern China that were generated in a collisional orogeny. We conclude that early Yanshanian (199.6–133.9 Ma) mantle–crust-derived magmatism caused by the subduction of the Palaeo-Pacific Plate was the main source of Mo deposits in the Shulan area.

The Dengshang Mo deposit is a recently recognized porphyry-type system within the Yanliao Mo metallogenic belt of northern Hebei Province. However, its ore-hosting rhyolitic porphyry emplacement age and petrogenesis remain insufficiently understood. This study integrates petrography, zircon U–Pb geochronology, Lu–Hf isotope analysis, zircon trace element geochemistry, and whole-rock major- and trace element data to investigate the petrogenesis of the Dengshang rhyolitic porphyry and its genetic relationship with Mo mineralization. The ore-hosting porphyry is predominantly composed of quartz and plagioclase phenocrysts. LA-ICP-MS zircon U–Pb dating yields an emplacement age of 168.3 ± 1.2 Ma, indicating that the rhyolitic porphyry was emplaced during a Middle Jurassic magmatic episode. Petrological and geochemical characteristics classify the Dengshang rhyolitic porphyry as an I-type granite. Zircon ε_Hf(t) values range from −0.93 to −7.29, corresponding to two-stage model ages (T_DM²) of 1.27–1.67 Ga, which suggests derivation from partial melting of the Mesoproterozoic lower crust. Zircon trace elements display significant positive Ce anomalies (δCe = 10.14–332.85), and calculated oxygen fugacities (ΔFMQ = −0.65 to +2.77; median = +0.51) indicate moderately oxidized magmatic conditions conducive to Mo enrichment. These results collectively imply that the Dengshang rhyolitic porphyry was emplaced at ~168 Ma associated with paleo-Pacific plate subduction. This geodynamic setting triggered partial melting of Mesoproterozoic lower crust, producing oxidized magmas that experienced fractional crystallization prior to shallow emplacement. Our findings elucidate the petrogenesis of the Dengshang rhyolitic porphyry and its control on Mo mineralization, and contribute new insight for understanding porphyry Mo genesis within the complex tectonic evolution of the Yanliao Mo Belt.

The Permian–Triassic magmatic record in the eastern Central Asian Orogenic Belt (CAOB) provides critical insights into the terminal stages of the Paleo-Asian Ocean (PAO) evolution, including collisional and post-collisional processes following its Late Permian closure. The northeastern China region, tectonically situated within the eastern segment of the CAOB, is traditionally known as the Xingmeng Orogenic Belt (XOR). This study integrates zircon U-Pb geochronology, whole-rock geochemistry, and zircon Hf isotopic analyses of intermediate-acid volcanic rocks and intrusive rocks from the former “Tongjiatun Formation” in the Faku area of northern Liaoning. The main objective is to explore the petrogenesis of these igneous rocks and their implications for the regional tectonic setting. Zircon U-Pb ages of these rocks range from 260.5 to 230.1 Ma, indicating Permian–Triassic magmatism. Specifically, the Gongzhuling rhyolite (260.5 ± 2.2 Ma) and Gongzhuling dacite (260.3 ± 2.4 Ma) formed during the Middle-Late Permian (270–256 Ma); the Wangjiadian dacite (243 ± 3.0 Ma) and Wafangxi rhyolite (243.9 ± 3.0 Ma) were formed in the late Permian-early Middle Triassic (256–242 Ma); the Haoguantun rhyolite (240.9 ± 2.2 Ma) and Sheshangou pluton (230.1 ± 1.7 Ma) were formed during the Late Middle-Late Triassic (241–215 Ma). Geochemical studies, integrated with the geochronological results, reveal distinct tectonic settings during successive stages: (1) Middle-Late Permian (270–256 Ma): Magmatism included peraluminous A-type rhyolite with in calc-alkaline series (e.g., Gongzhuling) formed in an extensional environment linked to a mantle plume, alongside metaluminous, calc-alkaline I-type dacite (e.g., Gongzhuling) associated with the subduction of the PAO plate. (2) Late Permian-Early Middle Triassic (256–242 Ma): Calc-alkaline I-type magmatism dominated, represented by dacite (e.g., Wangjiadian) and rhyolite (e.g., Wafangxi), indicative of a collisional uplift environment. (3) Late Middle-Late Triassic (241–215 Ma): Magmatism transitioned to high-K calc-alkaline with A-type rocks affinities, including rhyolite (e.g., Haoguantun) and plutons (e.g., Sheshangou), formed in a post-collisional extensional environment. This study suggests that the closure of the PAO along the northern margin of the North China Craton (NCC) occurred before the Late Triassic. Late Triassic magmatic rocks in this region record a post-orogenic extensional setting, reflecting tectonic processes following NCC-XOR collision rather than PAO subduction. Combined with previously reported age data, the tectonic evolution of the eastern segment of the CAOB during the Permian-Triassic can be divided into four stages: active continental margin (293–274 Ma), plate disintegration (270–256 Ma), final collision and closure (256–241 Ma), and post-orogenic extension (241–215 Ma).

More than 300 m of core from 18 wells, 4931 m of fullbore electrical image logs from 11 wells, and 3D seismic data were integrated to characterize fracture distribution in Carboniferous volcanic reservoirs of the Dinan Uplift, Junggar Basin. Five eruptive cycles, seven stages, and three volcanic-edifice types were identified. Thirty-three volcanic-edifice intervals from 10 wells (4052 m) were compared by structural position, fault distance, volcanic-edifice type, and facies-belt position. Tectonic fractures strike NW-SE to NNW-SSE and are parallel to reverse faults, with hanging-wall intervals showing a narrower orientation range than footwall intervals. Fracture line density (D_line) is weakly related to fault distance, with R² values of 0.03 and 0.24 for hanging-wall and footwall intervals, and this relationship differs among volcanic-edifice types. Lava-plateau edifices have the highest pooled D_line, whereas pyroclastic-cone edifices show the largest proximal–distal contrast. Core data indicate higher fracture densities in lavas and coarse heterogeneous pyroclastic rocks than in fine tuffs. Later reverse-fault deformation is expressed more consistently in fracture orientation than abundance, whereas fracture abundance varies among volcanic-edifice, facies-belt, and lithologic settings. Fracture distribution is therefore best understood by considering fault-related structural position together with inherited volcanic architecture rather than by applying a uniform distance-to-fault relationship.