In the Huanggangliang–Ganzhuermiao metallogenic belt in the southern Great Xing’an Range, the Haobugao Pb–Zn deposit is the most widespread skarn-type polymetallic deposit. The observed mineralization processes in this area are closely associated with both magmatic and tectonic activity. The zircon U–Pb ages of two granitoid phases are 134.0 ± 0.6 Ma and 133.4 ± 0.9 Ma (Early Cretaceous). High SiO₂ content (average mass fractions of 77.98 wt.% and 73.25 wt.%), high alkalinity (average mass fractions of 6.19 wt.% and 8.78 wt.%), and low CaO levels (average mass fractions of 0.16 wt.% and 0.12 wt.%) are characteristic of these rocks. They are also enriched in high-field-strength elements (HFSEs) (Th, U, Ta, Zr, Hf, etc.) and depleted in large ion lithophile elements (LILEs) (Ba, Sr, etc.). Furthermore, the Nb/Ta ratios (7.80~8.82, 10.00~10.83) point to a crustal origin of the magma. The zircon Hf isotopic compositions suggest that the melting of young crust derived from Meso-Neoproterozoic and Neoproterozoic depleted mantle gave rise to the magma in these granite porphyries. These rocks formed in an extensional environment driven by the subduction and retreat of the Paleo-Pacific plate during the Early Cretaceous.

The Apuseni-Banat-Timok-Srednogorie Metallogenic Belt is one of the most important polymetallic metallogenic belts in the western segment of the Tethys, where numerous porphyry-type, skarn-type, and epithermal deposits are developed. However, scholars have noted a lack of systematic chronological and geochemical studies of andesites within this belt. Furthermore, the metallodynamic mechanisms controlling mineralization—such as oceanic plate exhumation and plate tearing—remain controversial. To complement the available research, this study focuses on andesites from the Čukaru Peki area in Serbia and integrates zircon U-Pb dating, molybdenite Re-Os isotopic analysis, and whole-rock geochemical analysis. The results reveal that plagioclase andesitic breccia and fine-grained plagioclase amphibole andesite were emplaced during the Late Cretaceous. Consistently, the molybdenite isochron age (81.46 ± 0.60 Ma, MSWD = 1.30) constrains the mineralization event to the same period. Both rock types exhibit geochemical signatures typical of island arc volcanic rocks, characterized by high SiO₂ contents and low Al₂O₃, MgO, and TiO₂ contents, as well as pronounced fractionation between light and heavy rare earth elements (LREEs and HREEs). The magma source is the mantle wedge metasomatized by fluid-rich melts derived from the dehydration of the subducted oceanic crust. Additionally, the primary magma produced by partial melting of this metasomatized mantle wedge assimilated and was contaminated by continental crustal material predating the Vardar Ocean’s closure during its ascent. Our findings suggest that the regional andesites are products of the exhumation of the Vardar Ocean. This study aims to provide a theoretical foundation for mineral exploration in the Timok ore cluster and, simultaneously, support the identification of ore prospecting targets in andesite alteration zones.

The title in the original publication

The southern Great Xing’an Range is located in the overlap zone of the Paleo-Asian Ocean metallogenic domain and the Circum-Pacific metallogenic domain. It hosts numerous Sn-polymetallic deposits, such as Weilasituo, Bianjiadayuan, Huanggang, and Dajing, and witnessed multiple episodes of magmatism during the Late Mesozoic. The study area is situated within the Huanggangliang-Ganzhuermiao metallogenic belt in the southern Great Xing’an Range. The region has witnessed extensive magmatism, with Mesozoic magmatic activities being particularly closely linked to regional mineralization. We present petrographic, zircon U-Pb chronological, lithogeochemical, and Lu-Hf isotopic analyses of the Yexilinhundi granites. The results indicate that the granite porphyry and granodiorite were emplaced during the Late Jurassic. Both rocks exhibit high SiO₂, K₂O + Na₂O, differentiation index (DI), and 10,000 Ga/Al ratios, coupled with low MgO contents. They show distinct fractionation between light and heavy rare earth elements (LREEs and HREEs), exhibit Eu anomalies, and have low whole-rock zircon saturation temperatures (T_zr), collectively demonstrating characteristics of highly fractionated I-type granites. The εHf(t) values of the granites range from 0.600 to 9.14, with young two-stage model ages (T_DM2 = 616.0~1158 Ma), indicating that the magmatic source originated from partial melting of Mesoproterozoic-Neoproterozoic juvenile crust. This study proposes that the granites formed in a post-collisional/post-orogenic extensional setting associated with the subduction of the Mongol-Okhotsk Ocean, providing a scientific basis for understanding the relationship between the formation of Sn-polymetallic deposits and granitic magmatic evolution in the study area.