Seawater intrusion significantly affects the microbial communities within coastal aquifers. Investigating the spatial distribution of groundwater microbial communities in coastal regions is crucial for understanding seawater intrusion. The primary objective of this study is to develop a novel microbial index-based method for detecting seawater intrusion. Groundwater microbial samples were collected and sent to the laboratory in the west coastal area of Longkou City, Shandong Province. By characterizing the microbial community within the whole interval of seawater intrusion into fresh groundwater and discussing the effects of salt-freshwater displacement intensities on groundwater microbial communities, including diversity, structure, and function, using indoor domestication experiments, we reveal the response of microorganisms to the seawater intrusion process under in situ environmental conditions. The results show that the microbial community diversity is highest in environments with a seawater mixing proportion (P_(sm)) of 2.5% and lowest in those with a P_(sm) of 75%. When considering species abundance and evolutionary processes, the microbial community structure is similar at higher P_(sm) levels, while it is similar at lower P_(sm) levels based on the presence or absence of species. Tenericutes, Flavobacteriia, Rhodobacterales, Flavobacteriales, Rhodobacteraceae, Flavobacteriaceae, Cohaesibacteraceae, and Cohaesibacter are significantly positively correlated with the P_(sm). Strong salt-freshwater displacement enhanced the richness and evenness of the microbial community, whereas weak displacement showed the opposite trend. Strong displacement affects the functional profiles of the microbial community. This study effectively addressed the challenge of obtaining samples in coastal areas and also incorporated salt-freshwater displacement intensities, which can more comprehensively describe the microbial community characteristics within the groundwater of coastal aquifers.

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 Precambrian crystalline basement of Madagascar, shaped by its diverse geological history of magmatic activity, sedimentation, and metamorphism, is divided into six distinct geological units. Within this intricate geological framework, five primary types of uranium deposits are present. Despite the presence of these deposits, their resource potential remains largely unquantified. To address this, a comprehensive study was conducted on Madagascar’s uranium geochemical blocks. This study processed the original data of uranium elements across the region, following the “Theoretical Model Pedigree of Geochemical Block Mineralization” proposed by Xie Xuejin. The analysis is based on the geochemical mapping data of Madagascar at a scale of 1:100,000, which was jointly completed by the China–Madagascar team and involved the delineation of geochemical blocks and the division of their internal structures using the 15 km × 15 km window data. The study used an isoline with a uranium content greater than 3.2 × 10⁻⁶ as a boundary and considered five key factors for the classification of prospective areas. These factors included uranium bulk density, anomaly intensity, block structure, prospective area, and the tracing of uranium enrichment trajectories through the pedigree chart of 5-level geochemical blocks. By integrating these factors with potential resource assessment, uranium mining economics, and conditions for uranium mining and utilization, the study successfully classified and evaluated uranium resources in Madagascar. As a result, 10 uranium prospective areas were identified, ranging from Level I to IV, with 3 being Level I areas deemed highly promising for exploration and investment. For the first time, the study predicted a resource potential of 72,600 t of uranium resources, marking a significant step towards understanding Madagascar’s uranium endowment.

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