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.

Constraints on the Neoproterozoic evolution of the Himalayan terrane remain poorly understood due to the scarcity of Neoproterozoic magmatic rocks. In this study, we report for the first time Middle Neoproterozoic mafic rocks from the eastern Himalayan orogen. Zircon U–Pb dating indicates that these rocks crystallized at approximately 760 Ma and can be divided into two distinct groups. Group 1 mafic rocks have E-MORB-like compositions and are enriched in incompatible elements and exhibit relatively higher initial (⁸⁷Sr/⁸⁶Sr)_i ratios (0.7053–0.7063), lower positive whole-rock ε_Nd(t) values (3.0 to 3.4), and zircon ε_Hf(t) values ranging from 4.9 to 10.4. They also show low Nb/Th ratios and high Th/Yb, Nb/Yb, and (La/Sm)_N ratios, suggesting a lithospheric mantle source. In contrast, Group 2 mafic rocks have N-MORB-like compositions and are characterized by light rare earth element (LREE)-depleted patterns, lower initial (⁸⁷Sr/⁸⁶Sr)_i ratios (0.7033–0.7040), and higher positive whole-rock ε_Nd(t) (4.8 to 6.0) and zircon ε_Hf(t) values (4.6 to 10.9). Their high Nb/Th ratios and low Th/Yb, Nb/Yb, and (La/Sm)_N ratios indicate an origin involving interaction between the lithospheric mantle and depleted asthenospheric mantle. The absence of coeval volcanic and sedimentary records, combined with high La/Y and Ti/V ratios, suggests that these mafic rocks differ from typical arc or back-arc basin suites but are consistent with an intraplate setting. Integrating previous studies on multistage Neoproterozoic magmatism in India and the Himalayas, we propose that the ca. 760 Ma mafic rocks in the eastern Himalaya were likely formed within an intraplate continental rift system.

This study documents the first A1-type granite identified on the southern margin of the central Lhasa terrane: a two-mica syenogranite pluton in the Meibaqieqin region. Because A-type granite provides sensitive records of crustal melting and lithospheric extension, this pluton offers important insights into magmatic processes and tectonic evolution along the southern margin of the Lhasa terrane. We analyzed two sample suites collected from different sites within the same pluton using zircon U–Pb geochronology and Hf isotopes, whole-rock geochemistry and Nd isotope. Zircon U–Pb weighted mean ages were 130.5 ± 0.7 Ma and 130.0 ± 0.7 Ma, placing emplacement in the Early Cretaceous. Zircon ε_Hf(t) values ranged from −11.29 to −9.00 and −11.04 to −7.27, with two-stage Hf model ages (T_DM2) of 1.76–1.90 Ga and 1.65–1.89 Ga. Whole-rock ε_Nd(t) values clustered between −11.77 and −11.36, yielding two-stage Nd model ages (T_NdDM2) of 1.85–1.88 Ga. Geochemically, the pluton is high-K calc-alkaline. These isotopic signatures indicate derivation predominantly from ancient crustal sources with a little mantle material. Chondrite-normalized REE patterns are overall right-inclined and display a V-shaped profile. Together with trace-element characteristics, these features support classification as A1-type granite. Regional comprehensive data suggest that pluton emplacement was controlled mainly by lithospheric extension related to northward subduction of the Neo-Tethyan oceanic plate, with a lesser contribution from southward subduction along the Bangongco–Nujiang suture. The source characteristics and geodynamic context differ markedly from A2-type granites on the northern margin of the central Lhasa terrane, which reflect distinct magmatic sources and tectonic regimes.

The Xianglin Sn polymetallic deposit, located on the northwestern margin of the Cuonadong dome in the eastern Tethyan Himalaya, represents an important Sn-W-Be polymetallic system recently recognized in southern Tibet. This study investigates the nature and evolution of the ore-forming fluids and the mechanisms of cassiterite precipitation. Fluid inclusion petrography, microthermometry, and laser Raman spectroscopy were applied to inclusions from the cassiterite–sulfide, proximal cassiterite–quartz vein, distal cassiterite–quartz vein, and late fluorite–quartz vein stages. The fluid inclusions mainly comprise liquid-rich, vapor-rich, H₂O-CO₂ three-phase, and minor daughter-mineral-bearing inclusions. The cassiterite–sulfide stage contains the most complex inclusion assemblage, with homogenization temperatures of 326–399 °C and salinities of 2.4–10.5 wt.% NaCl equiv. The proximal cassiterite–quartz vein stage yields homogenization temperatures of 280–361 °C and salinities of 2.4–9.6 wt.% NaCl equiv., whereas the distal cassiterite–quartz vein stage records lower temperatures of 195–295 °C. The fluorite–quartz vein stage is characterized by low-temperature and low-salinity fluids. Raman spectra identify CO₂, N₂, CH₄, H₂S, and CaCO₃ daughter minerals, indicating a volatile-rich, relatively reduced H₂O-CO₂-NaCl hydrothermal system. These features suggest that the principal ore-forming fluids were dominantly magmatic–hydrothermal fluids exsolved from highly fractionated Miocene leucogranites. During upward and outward migration from the main detachment zone to peripheral fractures, the fluids experienced boiling, cooling, mixing, and multistage hydrothermal overprinting. Cassiterite precipitation during the cassiterite–sulfide stage was mainly triggered by boiling or phase separation, whereas the proximal cassiterite–quartz veins were controlled by progressive cooling and local phase separation. In contrast, distal cassiterite precipitation was more strongly influenced by fluid mixing and cooling. These results indicate that the Xianglin deposit records a structurally controlled proximal-to-distal magmatic–hydrothermal Sn mineralizing system related to the Cuonadong dome.