Petrogenesis of the Tailaihua ore-forming granites in the southern Great Xing’an Range, NE China: Implications for magma evolution and Be-Nb-Ta mineralization in Late Mesozoic

Late Mesozoic porphyry copper deposits in NE China: Post-collisional versus subduction-related magmatic systems

Crustal architecture controls on porphyry Cu and Mo fertility: constraints from zircon Hf isotopic mapping in the Great Xing’an Range, NE China

Magma mixing and Mantle-Crust evolution during the early Cretaceous: Insights from the mineral geochemistry of Huanggang MME-bearing granite in the southern Great Xing’an Range, NE China

To explore the hydrogeochemical characteristics and dominant water–rock interaction processes of thermal water in Lindian geothermal field (northern Songliao Basin, NE China), this study analyzed 16 thermal water samples (1900–3000 m depth) and 3 shallow groundwater samples using hydrochemical indices, water isotopes, and statistical methods (Pearson Correlation and Principle Component Analysis). Results show that the thermal water originates from precipitation and exhibits an “oxygen shift” indicating a long-time water–rock interaction under low to medium reservoir temperature. The thermal water is alkaline with a high TDS and dominated by Na+, Cl−, and HCO3−, and its hydrochemical facies changes from HCO3·Cl–Na to Cl·HCO3–Na and Cl–Na along the groundwater flow path. Leaching of halite, silicates, and carbonates is the primary process controlling solute accumulation. The geothermal reservoir is in a relatively closed, strong reducing environment, and thermal water reached water–rock equilibrium with respect to Na-, K-, Ca-, and Mg-alumino silicates. Principle Component Analysis identifies three key controlling factors, including mineral leaching, organic matter degradation, and sulfate reduction/mineral precipitation. This study establishes a hydrogeochemical baseline for the initial exploitation stage, providing a scientific basis for predicting long-term water quality changes and formulating differentiated sustainable development strategies for the Lindian geothermal field.

Mollisols enriched with organic matter (OM) and selenium (Se) are a critical resource supporting global food security. Nonetheless, concerns arise as climate change and agricultural practices threaten Mollisol sustainability. Particularly, how the environmental conditions and biogeochemical processes constrain coevolution of OM and Se in Mollisols of cold regions is an unresolved issue. By combining pedogeochemical and multi-isotopic analyses with ultrahigh-resolution molecular and bioenergetic characterization of Mollisols in NE China, this research presents new evidence that unique cold region soil-forming environments are central to the coenrichment of OM and Se. While Mollisol OM originated from both C3 (e.g., meadow) and C4 (e.g., corn) plants, paleoclimate and redox shifts emerged as critical factors driving variations in the compositional and structural characteristics of OM, and substantial differences with the underlying parent material. The abundance of moderately energetic organic compounds (e.g., lipids and proteins) in Mollisols accounts for Se retention as organic-bound species. Under agricultural land use, the loss of OM and Se was accompanied by increasing proportions of microbial metabolites and fulvic acid-bound and hydrophilic Se species. By highlighting the dominant environmental drivers of changes in OM and Se chemistry in Mollisols, our research provides new knowledge that helps guide sustainable management of this valuable natural resource.

Introduction The rapid and accurate identification of natural and non-natural seismic events is crucial for compiling comprehensive earthquake catalogs and assessing regional seismic risk. Methods This study utilized waveform data from seismic events (1.5 ≤ ML ≤ 3.5) recorded in Jilin Province between 2013 and 2024. Multiple physical features were extracted from the waveforms, and Support Vector Machine (SVM), Extreme Gradient Boosting (XGBoost), and Backpropagation Neural Network (BPNN) algorithms were employed to classify artificial blasts, mining collapses, and tectonic earthquakes. Results The study shows that all three models achieved over 94% accuracy in regional tests, with the SVM model performing best. In cross-regional validation, SVM maintained superior generalization capability, achieving an accuracy of 84%. Feature importance analysis confirmed that P-/S-wave spectrum amplitude and maximum P/S amplitude ratio served as the most critical features for event discrimination. Discussion This study validates the effectiveness of the selected features and machine learning methods for identifying low-magnitude multi-type seismic events; however, for events with strong regional characteristics, further development of cross-regional datasets or region-specific models is necessary to enhance classification accuracy.

The voluminous Mesozoic volcanic rocks developed in the Great Xing’an Range, northeastern China, have received extensive attention in recent decades. However, the timing and petrogenesis, as well as the related geodynamic processes of the Late Mesozoic volcanism, are still controversial. In this paper, we present the whole-rock geochemistry and zircon U–Pb ages for the Late Mesozoic volcanic rocks from the western part of the central Great Xing’an Range, which provide considerable insights into the geodynamic setting of the region. The zircon U-Pb dating results indicate that two main episodes of volcanism occurred in the central Great Xing’an Range, including in the Late Jurassic (ca. 147 Ma) and Early Cretaceous (ca. 142–125 Ma). These Late Mesozoic volcanic rocks display similar geochemical compositions, which are mainly intermediate–felsic, alkaline, peraluminous to metaluminous, enriched in large ion lithophile elements and light rare earth elements, and depleted in high-field-strength elements, indicating arc affinities in the subduction zone. The trace element compositions suggest that the magmatism was related to a post-collisional extensional environment. Combined with the spatial distribution and temporal migration of the Mesozoic magmatic events in the whole northeastern China region, we propose that these Late Jurassic–Early Cretaceous volcanic rocks formed in a continental arc setting, which was mainly related to the rollback of the subducted Paleo-Pacific oceanic plate.

This ‘Thematic Edition’ originated thanks to a symposium of the European Union of Geosciences held in Vienna in 2022. It is a collection of 14 contributions covering a wide spectrum of approaches and concepts ranging from mantle convection models, geophysical crustal characterization, regional synthesis of detrital zircon data, geochemistry, modern geochronology and synthesis of temperature/pressue data at orogenic scale. The Thematic Edition thus covers studies from North African Variscan outcrops, Variscan Europe from Iberia to Poland, and the southern part of the Altaids from NW China and Mongolia to NE China. Such an exceptional synthesis shows major differences between the North African–European Variscan belt and the Altaids in the final constitution of Pangaea in Late Carboniferous to Permian times. The western part of Pangaea was subject to deformation and thermal reworking associated with major collisions between Gondwana and the Variscan Collage at its northern margin, and Laurussia. The remnants of the main crustal thickening event are preserved in NW Africa in the form of high-pressure granulites, while Variscan Europe experienced transpressive reworking and oroclinal bendings related to dextral translation of Laurussia followed by indentation of Gondwana promontories. The eastern part of Pangaea experienced the arrival of a ribbon-like collage constituting the Tarim, Dunhuang, Alxa and North China blocks to the north and simultaneous shrinking of the Palaeo-Asian Ocean. During late Paleozoic times, and because of these processes, opposite subduction of the Palaeo-Asian oceanic plate operated beneath Mongolian blocks to the north and the Tarim–North China Collage in the south. This long-lasting subduction resulted in the formation of numerous intra-oceanic and Andean-type arcs and back-arcs later transformed into ephemeral oceans. All these oceanic basins were closed during the Permian, leading to the final mid-Permian to Triassic collision of Precambrian blocks with the Mongolian and Kazakhstan collages to the north. This resulted in multiple indentation effects and the formation of giant oroclinal structures reflected in the shape of the Altaids. All these events have one common link, namely the progressive opening and closure of the wedge-shaped Palaeo-Tethys Ocean south of the Variscan, Kazakhstan, Mongolian and Tarim–North China collages.

The Wunuer deposit is an important hydrothermal Zn-Pb-Ag-Mo polymetallic deposit in the central Great Xing’an Range, NE China. The zinc–lead polymetal mineralization is closely hosted by the volcanic rocks of the Manketouebo formation (rhyolite and lithic crystal tuff) and related to the Mesozoic granite porphyry. Field evidence and petrographic observations have identified three mineralization stages within this deposit from deep to shallow: (1) late magmatic stage with vein-type Mo mineralization characteristics and mainly related to the deep granite porphyry; (2) magmatic–hydrothermal transition stage characterized by breccia-type Zn mineralization, which occurred within a steep cryptoexplosive breccia; and (3) hydrothermal stage featured by vein-type Zn-Pb-Ag mineralization hosted by the ore-bearing fractured zone. In this contribution, we present the mineralogy, zircon U-Pb age, sphalerite Rb-Sr dating, whole-rock geochemistry, and Hf-S-Pb isotopes of the Wunuer deposit. LA-ICP-MS zircon U-Pb dating of the ore-related granite porphyry, rhyolite, and lithic crystal tuff suggests that the Mo mineralization from the late magmatic stage occurred between 144.8 Ma and 145.8 Ma. The Rb-Sr isochron dating of sphalerite indicates that the hydrothermal stage Zn mineralization age is 121 ± 2.3 Ma, which is related to the volcanism of Baiyin’gaolao Formation in the Wunuer area. The concentrated and positive δ34SV-CDT values (0.17‰~5.40‰) of sulfides, as well as uniform Pb isotope compositions of granite porphyry intrusion and galena, jointly imply a magmatic source of metallogenic materials for Pb-Zn mineralization. Whole-rock geochemistry and Hf-Pb isotopes reveal that the granite porphyry and rhyolite both originated from a mantle-derived juvenile component and assimilated by minor ancient crustal material in an extensional setting. Our study demonstrates the prospect of further exploration for two mineralization events in the hydrothermal polymetallic deposits of the central Great Xing’an Range.

Sulfide geochemistry has been widely employed to constrain formation processes in various deposit types; however, its use in porphyry W-Mo metallogenic systems is still relatively scarce. The Sansheng porphyry W-Mo deposit (Mo 24,361 t @ 0.226% and WO3 17,285 t @ 0.569%), situated in eastern Inner Mongolia, northeastern China, features with quartz vein and veinlet-disseminated W-Mo orebodies primarily localized within the cupolas of an Early Cretaceous granitic intrusion. This contribution provides a comprehensive analysis of the deposit’s geology, in situ sulfur isotopic signatures, and geochemical characteristics of wolframite and sulfides to decipher the formation of the Sansheng deposit. A narrow δ34S range (2.15‰–7.14‰) for sulfides, consistent Y/Ho (5.09–6.23) and Nb/Ta (7.20–19.96) ratios in wolframite, and pyrite Co/Ni (1–10) and As/Ni (>10) ratios collectively point to a shared source—the highly fractionated Sansheng granitic magma. Wolframite, pyrite, arsenopyrite, and chalcopyrite all host significant trace elements, though their enrichment patterns differ considerably among these minerals. Temporal variations in trace element concentrations in wolframite and sulfides reveal a decline in fluid temperature and oxygen fugacity from early to late stages. Greisenization is associated with tungsten mineralization, whereas sericitization facilitates Stage III sulfide precipitation.

Shale oil explorationin China’s clay-rich shale formationshas gained attention, but the origin and impact of clay minerals onreservoirs remain unclear. This study examines the Qingshankou Formationin the Songliao Basin using Nanomin analysis, X-ray diffraction, X-rayfluorescence analysis, TOC analysis, rock pyrolysis, and FE-SEM toinvestigate the origin, the evolution, and the pore structures ofclay mineral. Illite and I/S mixed layers dominate the matrix, whilecompaction disrupts their authigenic structures. Illite and I/S mixedlayers primarily originate from detrital deposition and transformationof smectite. Chlorite is mostly authigenic and increases with thermalmaturity. Illite and I/S mixed layers form elongated intergranularpores and microfractures, which significantly contribute to pore space,with their aligned axes pores playing a key role in microfractureformation. Authigenic chlorite primarily fills pores, while detritalchlorite exhibits discrete boundaries and alignment within the matrix.In comparison, authigenic chlorite pores are larger and more significantfor reservoir porosity than detrital chlorite pores. Detrital claymineral deposition promotes organic matter enrichment, while feldsparand quartz detritus deposition hinder it. These findings enhance theunderstanding of clay mineral evolution and the mechanisms of continentalshale oil reservoir formation and organic matter enrichment.

A Mid-Late Permian transition from oceanic subduction to continental collision in the northern margin of the North China Craton (NE China)

The history of soil gleyization in the Songnen Plain over the last 195 ka, as revealed by the Harbin loess-paleosol sequence, NE China

O-Hf-Mg isotopic signals of recycled oceanic crust in the Early Cretaceous I-type granites from NE China

Formation of the Da'anhe reduced gold skarn in NE China: Evidence from U-Pb geochronology, and whole-rock and mineral geochemistry

Permian-Triassic adakitic rocks in the Changchun-Yanji Suture, NE China: Constraints on the eastern extension of the Solonker Suture and Paleo-Asian Ocean closure

Genesis and geological significance of pyrite in the First Member of the Cretaceous Qingshankou formation of the Songliao Basin, NE China

Sphalerite geochemistry of the Hua’aobaote and Shuangjianzishan deposits in the southern Great Xing’an Range, NE China

Assessment of quantitative provenance reconstruction of river source-sink system and its geological significance: A case study of Songhua River system, NE China