Search Results (274)

The eastern Tianshan region in the Central Asian Orogenic Belt (CAOB) is characterized by multiple complex tectonic activity of uncertain historical contribution to the construction of the CAOB. This study utilizes a multi-proxy geochemical approach to characterize I-type monzogranite pluton rocks and their associated hornblende-rich dioritic enclaves to decipher the tectonic and magmatic evolution of the Xigebi area, eastern Tianshan. Zircon geochronology indicates a Triassic and Permian crystallization age of ca. 224.2 ± 1.7 Ma and ca. 268.3 ± 3.0 Ma for the host monzogranites and the dioritic enclaves, respectively. Major, trace and rare earth element distribution, together with Hf isotope systematics displaying noticeable positive εHf(t) anomalies for both rock types, point to partial melting of meta-mafic rocks in an intraplate extensional setting. The diorite was formed by the melting of lower crustal meta-igneous rocks mixed with mantle melts, and the monzogranite, predominantly from deep crustal meta-basalts contaminated by shallow metasedimentary rocks, with some degree of mixing with deeply sourced mantle magma. While both the host monzogranites and their dioritic enclaves are the products of upwelling magma, the younger Triassic monzogranites captured and preserved fragments of the dioritic Permian lower continental crust during crystallization. These multiple stages of magmatic underplating and crustal reworking associated with vertical stratification of the juvenile paleo-continental crust suggest the monzogranites and diorites indicate a change from a post-collisional setting to a regional intraplate regime on the southern margin of the CAOB. Full article

The Central Asian Orogenic Belt (CAOB) represents a crucial area for understanding the tectonic evolution of the Paleo-Asian Ocean and surrounding orogenic systems. This study investigates the petrology, geochronology, and geochemistry of volcanic and clastic rocks from Well HFD3 in the northern Songliao Basin, which provides key insights into the tectonic development of this region. Zircon U–Pb dating of tuff samples from the Linxi Formation provides an accurate age of 251.1 ± 1.1 Ma, corresponding to the late Permian. Geochemical analyses show that the clastic rocks are rich in SiO₂ (63.5%) and Al₂O₃ (13.7%), with lower K₂O/Na₂O ratios (0.01–1.55), suggesting low compositional maturity. Additionally, the trace element data reveal enrichment in light rare earth elements (LREEs) and depletion in Nb, Sr, and Ta, with a negative Eu anomaly, which indicates a felsic volcanic arc origin. The Chemical Index of Alteration (CIA) values (53.2–65.8) reflect weak chemical weathering, consistent with cold and dry paleo-climatic conditions. These findings suggest that the Linxi Formation clastic rocks are derived from felsic volcanic arcs in an active continental margin environment, linked to the subduction of the Paleo-Asian Ocean slab. The sedimentary conditions reflect a gradual transition from brackish to freshwater environments, corresponding with the final stages of subduction or the onset of orogeny. Full article

The Ouarzazate Group in the Anti-Atlas Belt of southern Morocco, part of the West African Craton (WAC), is a significant Proterozoic lithostratigraphic unit formed during the late Ediacaran period. It includes extensive volcanic rocks associated with the early stages of Iapetus Ocean opening. Zircon U-Pb dating and geochemical analyses of the Oued Dar’a Caldera (ODC) volcanic succession in the Saghro Massif reveal two major eruptive cycles corresponding to the lower and upper Ouarzazate Group. The 1st cycle (588–563 Ma) includes pre- and syn-caldera volcanic succession characterized by basaltic andesite to rhyolitic rocks, formed in a volcanic arc setting through lithospheric mantle-derived mafic magmatism and crustal melting. A major caldera-forming eruption occurred approximately 571–562 Ma, with associated rhyolitic dyke swarms indicating a larger caldera extent than previously known. The 2nd cycle (561–543 Ma) features post-caldera bimodal volcanism, with tholeiitic basalts and intraplate felsic magmas, signaling a shift to continental flood basalts and silicic volcanic systems. The entire volcanic activity spans approximately 23–40 million years. This succession is linked to late Ediacaran intracontinental super-eruptions tied to orogenic collapse and continental extension, likely in association with the Central Iapetus Magmatic Province (CIMP), marking a significant transition in the geodynamic evolution of the WAC. Full article

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). Full article

The Yangtze Block, with its widespread Neoproterozoic mafic–felsic magmatic rock series and volcanic–sedimentary rock assemblages, is one of the key windows for reconstructing the assembly and fragmentation process of Rodinia. This study focuses on the Taoyuan syenogranite from the Micangshan Massif on the northern Yangtze Block, by conducting systematic chronology, mineralogy, and geochemistry analyses to investigate their source, petrogenesis, and tectonic setting. LA-ICP-MS U–Pb geochronology reveals that the medium- to coarse-grained and medium- to fine-grained syenogranites have crystallization ages of 878 ± 4.2 Ma and 880 ± 6.5 Ma, respectively. These syenogranites have aluminum saturation index (A/CNK) values ranging from 0.79 to 1.06, indicating quasi-aluminous to weakly peraluminous compositions, and are classified as calc-alkaline I-type granites. The geochemical indicators of these rocks, including Mg^# (44–48, mean 46), Zr/Hf (40.07), Nb/La (0.4), and zircon εHf(t) values (+9.2 to +10.9), collectively indicate a depleted lithospheric mantle source. The mantle source was metasomatized by subduction-derived fluids and sediment melts prior to partial melting as evidenced by their higher Mg^#, elevated Ba content, and distinctive ratios (Rb/Y, Nb/Y, Th/Yb, Th/Sm, Th/Ce, and Ba/La). Integrating regional data, this study confirms crust–mantle interaction along the northern Yangtze during the early Neoproterozoic, supporting a sustained subduction-related tectonic setting. Full article

The Qieliekeqi siderite deposit, located in the Tashkurgan block of western Kunlun, is a carbonate-hosted iron deposit with hydrothermal sedimentary features. This study integrates whole-rock geochemistry, stable isotopes, and zircon U–Pb–Hf data to investigate its metallogenic evolution. Coarse-grained siderite samples, formed in deeper water, exhibit average Al₂O₃/TiO₂ ratios of 29.14, δEu of 2.69, and δCe of 0.83, indicating hydrothermal fluid dominance with limited seawater mixing. Banded samples from shallower settings show an average Al₂O₃/TiO₂ of 17.07, δEu of 3.18, and δCe of 0.94, suggesting stronger seawater interaction under oxidizing conditions. Both types are enriched in Mn, Co, and Ba, with low Ti and Al contents. Stable isotope results (δ¹³C_PDB = −6.0‰ to −4.6‰; δ¹⁸O_SMOW = 16.0‰ to 16.9‰) point to seawater-dominated fluids with minor magmatic and meteoric contributions, formed under open-system conditions at avg. temperatures of 53 to 58 °C. Zircon U–Pb dating yields an age of 211.01 ± 0.82 Ma, with an average εHf(t) of −3.94, indicating derivation from the partially melted ancient crust. These results support a two-stage model involving Late Cambrian hydrothermal sedimentation and Late Triassic magmatic overprinting. Full article

Many granitic enclaves are developed in the volcanic channel of the Xiangshan volcanic basin. To explore their genesis, this study examined the petrography, geochemistry, LA-ICP-MS zircon U–Pb chronology, and zircon Hf isotopes of the granitic enclaves and compared them with the porphyroclastic lavas. In general, the granitic enclaves and porphyroclastic lavas have similar structures, and the rock-forming minerals and accessory minerals have relatively close compositions. In terms of rock geochemical characteristics, the granitic enclaves are richer in silicon and alkalis but have lower abundances of aluminum, magnesium, iron, and calcium than the porphyroclastic lavas. Rb, Th, K, Sm, and other elements are more enriched, whereas Ba, Ti, Nb, P, and other elements are more depleted. The granitic enclaves have lower rare earth contents (195.53 × 10⁻⁶–271.06 × 10⁻⁶) than the porphyroclastic lavas (246.67 × 10⁻⁶–314.27 × 10⁻⁶). The rare earth element distribution curves of the two are generally consistent, both right-leaning, and enriched with light rare earth patterns. The weighted average zircon U–Pb ages of two granitic enclave samples were 135.45 ± 0.54 Ma (MSWD = 0.62, n = 17) and 135.81 ± 0.60 Ma (MSWD = 0.40, n = 20), respectively, which are consistent with the weighted average age of a single porphyroclastic lava sample of 134.01 ± 0.53 Ma (MSWD = 2.0, n = 20). The zircons of the two kinds of rocks crystallize at almost the same temperature. The consistent trend of the rare earth element distribution curve of zircons in the granitic enclaves and the porphyroclastic lava samples indicates that the zircons of the two samples were formed in the same stage. The formation process of granitic enclaves may be that the lower crustal melt is induced to rise, and the crystallization differentiation occurs in the magma reservoir and is stored in the form of crystal mush, forming a shallow crystal mush reservoir. The crystal mush reservoir is composed of a large number of rock-forming minerals such as quartz, feldspar, and biotite, as well as accessory mineral crystals such as zircon and flowable intergranular melt. In the later stage of magma high evolution, a small and short-time magmatic activity caused a large amount of crystalline granitic crystal mush to pour into the volcanic pipeline. In the closed system of volcanic pipeline, the pressure and temperature decreased rapidly, and the supercooling degree increased, and the immiscibility finally formed pale granitic enclaves. Full article

The tectonic evolution of the Paleo-Pacific Ocean and the destruction mechanism of the North China Craton (NCC) are still controversial. In this study, we conducted zircon U-Pb dating, whole-rock geochemistry, and Sr-Nd-Hf isotope analyses on the Weiyuanpu mafic–ultramafic intrusions in the eastern segment of the northern margin of the NCC to discuss their petrogenesis and tectonic implications. The Weiyuanpu mafic–ultramafic intrusions consist of troctolite, hornblendite, hornblende gabbro, gabbro, and minor diorite, anorthosite, characterized by cumulate structure. The main crystallization sequence of minerals is olivine → pyroxene → magnetite → hornblende. The zircon U-Pb ages of hornblendite, hornblende grabbro, and diorite are ~170Ma. Geochemical characteristics exhibit low-K tholeiitic to calc-alkaline series, enriched in light rare-earth elements (LREE) and significant large-ion lithophile elements (LILE), and depleted in high-field-strength elements (HFSE). Sr-Nd isotopic compositions are I_Sr = 0.7043–0.7055, εNd(t) = −0.7 to +0.9, and zircon εHf (t) values range from +3.4 to +8.7. These results suggest that the source region was a phlogopite-bearing garnet lherzolite mantle metasomatized by subduction fluids. The study reveals that the northeastern margin of the NCC was in a back-arc extensional setting due to the subduction of the Paleo-Pacific Ocean during the Middle Jurassic, which caused lithosphere thinning and mantle melting in this region. Full article

The Late Paleozoic granitoids widely distributed in the central section of the East Kunlun Orogenic Belt (EKOB) are responsible for the constraints on its post-collisional extensional processes. We report the whole-rock geochemical compositions, zircon U-Pb ages, and zircon Hf isotope data of granites in the western Kendewula area. The granites, dated between 413.7 Ma and 417.7 Ma, indicate emplacement during the Early Devonian period. The granite is characterized by high silicon content (72.45–78.96 wt%), high and alkali content (7.59–9.35 wt%), high 10,000 × Ga/Al values, and low Al2O3 (11.29–13.32 wt%), CaO (0.07–0.31 wt%), and MgO contents (0.16–0.94 wt%). The rocks exhibit enrichment in large-ion lithophile element (LILE) content and high-field-strength element (HFSE) content, in addition to strong losses, showing significant depletion in Ba, Sr, P and Eu. These geochemical characteristics correspond to A2-type granites. The values of Rb/N and Ba/La and the higher zircon saturation temperature (800~900 °C) indicate that the magma source is mainly crustal, with the participation of mantle materials, although limited. In addition, the zircon εHf(t) values (−4.3–3.69) also support this view. In summary, the A2-type granite exposed in the western Kendewula region formed against a post-collisional extensional setting background, suggesting that the Southern Kunlun Terrane (SKT) entered a post-orogenic extensional phase in the evolution stage since the Early Devonian. The upwelling of the asthenospheric mantle of the crust, triggered by crustal detachment and partial melting, likely contributed to the flare-up of A2-type granite during this period. By studying the nature of granite produced during orogeny, the evolution process of the formation of orogenic belts is discussed, and our understanding of orogenic is enhanced. Full article

The Southern Beishan Orogenic Belt (SBOB), an integral part of the Southern Central Asian Orogenic Belt (CAOB), is characterized by extensive Late Paleozoic magmatism. These igneous rocks are the key to studying the tectonic evolution process and the ocean–continent tectonic transformation in the southern margin of the CAOB and Paleo-Asian Ocean. We present zircon U-Pb chronology, in situ Lu-Hf isotopes, and whole-rock geochemistry data for Early–Middle Devonian volcanic rocks in the Sangejing Formation and granites from the Shuangyingshan-Huaniushan (SH) unit in the SBOB. The Wudaomingshiu volcanic rocks (Ca. 411.5 Ma) are calc-alkaline basalt-basaltic andesites with low SiO₂ (47.35~55.59 wt.%) and high TiO₂ (1.46~4.16 wt.%) contents, and are enriched in LREEs and LILEs (e.g., Rb, Ba, and Th), depleted in HREEs and HFSEs (Nb, Ta, and Ti), and weakly enriched in Zr-Hf. These mafic rocks are derived from the partial melting of the depleted lithosphere metasomatized by subduction fluid and contaminated by the lower crust. Wudaomingshui’s high-K calc-alkaline I-type granite has a crystallization age of 383.6 ± 2.2 Ma (MSWD = 0.11, n = 13), high Na₂O (3.46~3.96 wt.%) and MgO (1.25~1.68 wt.%) contents, and a high DI differentiation index (70.69~80.45); it is enriched in LREEs and LILEs (e.g., Rb, Ba, and Th) and depleted in HREEs and HFSEs (e.g., Nb, Ta, and Ti). Granites have variable zircon ε_Hf(t) values (−2.5~3.3) with Mesoproterozoic T_DM2 ages (1310~1013 Ma) and originated from lower crustal melting with mantle inputs and minor upper crustal assimilation. An integrated analysis of magmatic suites in the SBOB, including rock assemblages, geochemical signatures, and zircon ε_Hf(t) values (−2.5 to +3.3), revealed a tectonic transition from advancing to retreating subduction during the Early–Middle Devonian. Full article

The attributes of Late Paleozoic magmatic events are of paramount significance in elucidating the tectonic evolution of the Ulanhot region, which is located in the middle of the Hegenshan–Heihe tectonic belt (HHTB). This study undertook a comprehensive investigation of the petrography, LA–ICP–MS zircon U–Pb dating, whole rock geochemistry, and zircon Hf isotopes of the Early Carboniferous volcanic rocks. The volcanic rocks are predominantly composed of andesite, schist (which protolith is rhyolitic tuff), and rhyolitic tuff. The results of zircon U–Pb dating reveal that the formation ages of volcanic rocks are Early Carboniferous (343–347.4 Ma). Geochemical characteristics indicate that the andesites possess a comparatively elevated concentration of Al₂O₃, alongside diminished levels of MgO and TiO₂, belonging to the high-K calc-alkaline series. The zircon εHf(t) of the andesites range from −13 to 9.4, while the two-stage Hf model ages span from 697 to 1937 Ma. The felsic volcanic rocks have high contents of SiO₂ and Na₂O + K₂O, low contents of MgO and TiO₂, and belong to high-K to normal calc-alkaline series. The zircon εHf(t) values of the felsic volcanic rocks range from −12.8 to 10, while the two-stage Hf model ages span from 693 to 2158 Ma. The Early Carboniferous volcanic rocks exhibit a notable enrichment in large ion lithophile elements (LILEs, such as Rb, K, Ba) and light rare earth elements (LREEs), depletion in high-field-strength elements (HFSEs, including Nb, Ta, Ti, Hf), as well as heavy rare earth elements (HREEs). The distribution patterns of the rare earth elements (REEs) demonstrate a conspicuous right-leaning tendency, accompanied by weak negative Eu anomalies. These characteristics indicate that the andesites represent products of multistage mixing and interaction between crustal and mantle materials in a subduction zone setting. The felsic volcanic rocks originated from the partial melting of crustal materials. Early Carboniferous igneous rocks formed in a volcanic arc setting are characteristic of an active continental margin. The identification of Early Carboniferous arc volcanic rocks in the Central Great Xing’an Range suggests that this region was under the subduction background of the oceanic plate subduction before the collision and amalgamation of the Erguna–Xing’an Block and the Songnen Block in the Early Carboniferous. Full article

Haigou deposit, located in Dunhua City, southeast Jilin Province, NE China, is a large-scale gold deposit. The gold ore body is categorized into two types: quartz-vein type and altered rock type, with the quartz-vein type being predominant. The vein gold ore body primarily occurs within the monzonite granite and monzonite rock mass in the Haigou area and is controlled by fault structures trending northeast, northwest, and near north-south. In order to constrain the age and tectonic setting of quartz vein-type gold mineralization, we conducted a detailed underground investigation and collected samples of monzonite granite and pyroxene diorite porphyrite veins related to quartz-vein-type gold mineralization for LA-ICP-MS zircon U-Pb dating and whole-rock main trace element data testing to confirm that monzonite granite is closely related to gold mineralization. Pyroxene diorite porphyry and gold mineralization were found in parallel veins. The zircon U-Pb weighted mean ages of monzonite and pyroxene diorite porphyrite veins are 317.1 ± 3.5 Ma and 308.8 ± 3.0 Ma, respectively, indicating that gold mineralization in monzonite, pyroxene diorite porphyrite veins, and quartz veins occurred in the Late Carboniferous. The monzonite granite and pyroxene diorite porphyrite veins associated with quartz vein-type gold mineralization have high SiO₂, high K, and high Al₂O₃ and are all metaluminous high-potassium calc-alkaline rock series. Both of them are relatively enriched in light rare earth elements (LREE) and macroionic lithophile elements (LILE: Rb, Ba, K, etc.), but deficient in heavy rare earth elements (HREE) and high field strength elements (HFSE: Nb, Ta, P, Ti, etc.), the monzonitic granite Eu is a weak positive anomaly (δEu = 1.15–1.46), the pyroxene diorite porphyre dyke Eu is a weak positive anomaly (δEu = 1.09–1.13), and the Nb and Ta are negative anomalies. The Th/Nb values are 0.28–0.73 and 1.48–2.05, and La/Nb are 2.61–4.74 and 4.59–5.43, respectively, suggesting that diagenetic mineralization is the product of subduction in an active continental margin environment. In recent years, scholarly research on Sr, Nd, and Pb isotopes in Haigou rock masses has indicated that the magmatic source region in the Haigou mining areas is complex. It is neither a singular crustal source nor a mantle source but rather a mixed crust-mantle source, primarily resulting from the partial melting of lower crustal materials, with additional contributions from mantle-derived materials. In summary, the metallogenic characteristics, chronology data, geochemical characteristics, and regional tectonic interpretation indicate that at least one phase of magmatic-hydrothermal gold mineralization was established in the Late Carboniferous as a result of the subduction of the Paleo-Asian ocean plate at the northern margin of the North China Craton. Full article

The Cenozoic Nankang Basin in China records a complex series of tectonic, magmatic, metamorphic, and sedimentary events associated with the surrounding Shiwanshan, Liuwanshan, and Yunkaishan orogenic systems. The Nankang Basin is a critical location for studying the Cenozoic tectono–sedimentary evolution and strategic mineral resources of the southern Cathaysia Block. We used core samples from multiple boreholes and regional geological survey data to analyze the rock assemblages, sediment types, and sedimentary facies of the Nankang Basin. In addition, we analyzed the detrital zircon U–Pb geochronology, sandstone detrital compositions, heavy mineral assemblages, and major element geochemistry. The detrital zircon grains from Cenozoic sandstones in the Nankang Basin have age peaks at 2500–2000, 1100–900, 500–400, and 300–200 Ma, with most grains having ages of 500–400 or 300–200 Ma. The provenance analysis indicates that the 300–200 Ma zircon grains originated mainly from the Liuwanshan pluton; the 500–400 Ma zircon grains originated from the Ningtan pluton; and the 2500–2000 and 1100–900 Ma zircon grains originated from the Lower Silurian Liantan Formation and Middle Devonian Xindu Formation. This indicates that the provenance of Cenozoic sandstones in the Nankang Basin primarily originates from Paleozoic–Early Mesozoic igneous in the surrounding area, while the regional old sedimentary rocks possibly serve as intermediate sedimentary reservoirs. The detrital compositions of the sandstones and heavy mineral assemblages indicate a change in the tectonic setting during the deposition of the Nankang and Zhanjiang Formations, with a change in the source of the sediments due to the uplift of the Shizishan. During the deposition of the Nankang Formation, the sediment transport direction was to the NNW, whereas during the deposition of the Zhanjiang Formation, it was to the NNE. The uplift of the Shizishan most probably occurred during the late Neogene and early Quaternary, separating the Hepu and Nankang Basins. Full article

Regolith-hosted rare-earth element (REE) deposits are some of the most important types of REE deposits. The relationship between Late Paleozoic and Early Mesozoic granite and regolith-hosted REE deposits is still poorly studied. Detailed geochronology, geochemistry, and rare-earth mineralogy analyses of Early Triassic granite in the South China Block were conducted. The geochronological results showed that four representative granite samples yielded formation ages of 245 ± 1 Ma, 244 ± 1 Ma, 244 ± 1 Ma, and 244 ± 2 Ma, respectively. The granites show geochemical affinity to A-type granite. They are characterized by enrichment in Rb, Th, and U, are depleted in Ba, Sr, P, and Ti, and show obvious negative Nb and Ta anomalies. They have high light rare-earth element (LREE) and low heavy rare-earth element (HREE) contents, with obvious negative Eu anomalies. They were derived from the partial melting of a sediment source and underwent intense fractional crystallization during the magma evolution process. They contain a certain number of rare-earth-element-bearing minerals, such as monazite, xenotime, apatite, and zircon. Their REE compositions and mineral associations are similar to those of the parent rocks from typical regolith-hosted REE deposits in South China. The highly weathered horizon at the ridge of the granite weathering crust profile has the highest REE content. A comprehensive analysis indicated that the degree of magma evolution, geomorphology, and weathering are important factors controlling the formation of regolith-hosted REE deposits in the area. Full article

The Wubaduolai copper deposit, a newly discovered porphyry-type deposit located in the western section of the Gangdese metallogenic belt, shows great potential for mineralization. Investigating the ore-bearing potentiality of the adakitic granite in this area is crucial for identifying concealed ore bodies and assessing the metallogenic potential. This paper presents the zircon U-Pb dating, Hf isotope analysis, and whole-rock major and trace geochemical analysis of the plutons in the Wubaduolai mining area. The results indicate that the zircon U-Pb concordia age of the monzogranite is 15.7 ± 0.1 Ma, while the granodiorite porphyry has a concordia age of 15.9 ± 0.2 Ma, both corresponding to a Miocene diagenesis. The geochemical data show that both plutons belong to the high-K calc-alkaline series, characterized by a relative enrichment of large-ion lithophile elements (K, Rb, Ba, and Sr) and a depletion of high-field-strength elements (Nb, Ta, and Ti). Both plutons are characterized by low Y, low Yb, and high Sr/Y values, displaying the typical geochemical characteristics of adakites. Their mineral composition is similar to that of adakite. The ε_Hf(t) values of the monzogranite and granodiorite porphyry range from −5.34 to −2.3 and −5.2 to −3.43, respectively, with two-stage model ages (T_DM2) of 1246–1441 Ma and 1318–1432 Ma. Based on the regional data and this study, the plutons in the Wubaduolai mining area formed in a post-collision setting following the India–Asia continental collision. The magma source is identified as the partial melting of a thickened, newly formed lower crust. The above characteristics are consistent with the diagenetic and metallogenic ages, magma source, and dynamic backgrounds of the typical regional deposits. Full article