The Lesser Xing’an-Zhangguangcai Range tectonic belt in northeastern China is located along the eastern margin of the Central Asian Orogenic Belt and serves as the key to understanding the tectonic transition between the Paleo-Asian Ocean and Paleo-Pacific regimes during the Early Mesozoic. This study presented the zircon U-Pb geochronology, Hf isotope, and whole-rock geochemistry of Early Jurassic syenogranites from the northern Zhangguangcailing Range. The LA-ICP-MS zircon dating result indicates a crystallization age of 194 ± 2 Ma. Integrated with regional data, this study confirmed that the Early Mesozoic magmatism in the region was concentrated in the Early Jurassic (180–200 Ma). The granites displayed typical arc-related features, including (1) high SiO₂ (70.59–76.81 wt.%), alkali enrichment (Na₂O + K₂O = 7.65–8.38 wt.%), low Mg and Fe contents, classifying them as the high-K calc-alkaline metaluminous to weakly peraluminous (A/CNK = 0.99–1.04); (2) strong LREE enrichment with weak Eu anomalies (δEu = 0.44–0.81) and HREE depletion ((La/Yb)_N = 3.38–16.17); and (3) enrichment in LILEs (Rb, K) with the corresponding depletion in HFSEs (Nb, Ta, and Ti). Harker diagrams showed negative correlations between SiO₂ and MgO, TiO₂, CaO, TFeO, P₂O₅, and Eu, indicating fractional crystallization involving amphibole, ilmenite, apatite, and feldspar. The zircon εHf(t) values (+2.7 to +5.0) and the corresponding Meso-to Neoproterozoic crustal model ages (T_DM2 = 915–1067 Ma) suggested that the magma originated from partial melting of the Meso-Neoproterozoic mafic lower crust at amphibolite facies. The geochemical and isotopic data collectively identified these rocks as I-type granite. In a regional tectonic context, their formation was interpreted to reflect an active continental margin environment driven by the westward subduction of the Paleo-Pacific Plate during the Early Jurassic, potentially influenced by the closure of the Mudanjiang Ocean, a branch of the Paleo-Pacific.

The Qiyimuchang lead–zinc deposit is an important deposit in the Erguna Massif on the west slope of Daxinganling, for which the material source and age of mineralization remain unclear. The lead–zinc deposit in Qiyimuchang has been observed to occur in Jurassic volcanic strata as a vein-like orebody, and its strike is nearly perpendicular to that of the strata and the regional structures of the orogenic belt. The ore is mainly composed of sphalerite, galena, chalcopyrite, pyrite, and quartz, and hydrothermal alteration zones dominated by silicification, fluoritization, and pyritization are common within 1–5 m on both sides of the vein. The metasomatic lead–zinc mineralization is characterized by a massive vein structure. The mineralization process can be divided into three stages, pre-ore (mainly quartz, arsenopyrite and a small amount of pyrite), ore-formation (pyrite, chalcopyrite, sphalerite, galena, fluorite, and a small amount of tetrahedrite), and post-ore (quartz-calcite veinlets with a small amount of pyrite). Element and isotope geochemical studies show that the trace element compositions of the wall rocks (andesite, tuff, etc.) of Jurassic volcanic rocks in the ore bodies and surrounding rocks reflect affinity or similarity between them. The S isotopic composition of sulfide minerals in the metallogenic stage (δ ³⁴S_V-CDT = 1.6‰~4.8‰) indicate the sulfur isotopic composition of the magma. The Pb isotopic compositions of sulfide minerals (38.5–38.39, 15.55–15.62, and 18.33–18.41 for ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁶Pb/²⁰⁴Pb, respectively) in the metallogenic stage are relatively concentrated and close to the average Pb isotopic compositions of the mantle and average Pb isotopic composition of an orogenic belt, indicating that the ore-forming metals are likely to be a mixed source of crust and mantle. A new zircon U-Pb age of 150.8 ± 1.3 Ma (MSWD = 0.74) was obtained from andesitic tuff. Collectively considering the regional geology and ore deposit geological analysis, the lead–zinc mineralization in Qiyimuchang possibly occurred during the early Cretaceous. The ore-forming processes belong to Cretaceous magmatic-hydrothermal activity in extensional tectonic setting.

The Bei’an is located in the northern part of the Songnen Plain, and there has been little research on its loess formation and palaeoenvironment. This study provides a comprehensive analysis of the AMS14C, OSL, magnetic susceptibility, grain size characteristics, and lithological features of the Bei’an loess. The results show that the Bei’an loess roughly corresponds to the Guxiangtun Formation and upper part of the Harbin Formation. It exhibits low magnetic susceptibility values without any clear cyclical characteristics. The grain size frequency curve shows a unimodal distribution, indicating a sandy loam composition that differs from typical loess found in the eastern part of the Songnen Plain. However, Kd values, discriminant functions, and grain size plots (C-M, L-M, A-M charts) indicate that it does exhibit characteristics consistent with aeolian deposits. It is concluded that the Bei’an loess primarily represents aeolian deposition with secondary transportation and modification by rivers and mudflows. This suggests that during the late Pleistocene period in northern Songnen Plain was characterized by a dry-cold glacial environment. This study on Bei’an loess provides fundamental data for analyzing material sources for loess in northern Songnen Plain and holds significant importance for understanding the formation of loess in this region as well as beyond.

The Ailinwudui gold deposit is located in central Jilin Province and represents a newly discovered typical vein-type gold deposit hosted in a Paleozoic metamorphic rock series in recent years. At present, the metallogenic epoch and regional metallogenic tectonic setting of the deposit remain poorly constrained, which seriously restricts the understanding of gold metallogenic regularities and subsequent mineral exploration deployment in central Jilin. Previous studies indicate that the Ailinwudui gold deposit is a structurally controlled vein-type gold deposit. In this study, zircon U-Pb and muscovite ⁴⁰Ar/³⁹Ar geo-chronology were employed to precisely constrain the metallogenic timing of the gold mineralization. Zircon U-Pb dating yields an emplacement age of 174.7 ± 0.85 Ma for the granodiorite and a formation age of 209.5 ± 1.40 Ma for the rhyolite porphyry. Muscovite ⁴⁰Ar/³⁹Ar dating yields a plateau age of 180.39 ± 1.83 Ma, which confines the gold mineralization to the Early–Middle Jurassic. Whole-rock geochemical results reveal that the granitoids in the study area are enriched in large-ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in high-field-strength elements (HFSEs), showing typical arc-related magmatic affinities. The formation of this gold deposit is related to the subduction of the Paleo-Pacific Plate during the Early–Middle Jurassic. The research results can provide important geochronological and geochemical evidence for the study of gold metallogenic mechanisms and mineral exploration in central Jilin Province.

Heilongjiang Province, northeastern China, occupies a key metallogenic position between the eastern Central Asian Orogenic Belt and the western Pacific continental margin. This review integrates published geological, geochronological, fluid–inclusion, and H–O–S–Pb isotope data to evaluate tectonic controls on endogenic gold mineralization. Four principal metallogenic episodes are recognized: Caledonian porphyry-related mineralization associated with Paleo–Asian Ocean subduction–accretion; Variscan skarn-forming magmatic–hydrothermal activity; Indosinian post-collisional structurally focused and epithermal hydrothermal activity; and Yanshanian mineralization characterized by Late Jurassic compressional reworking followed by a dominant Cretaceous Paleo–Pacific-related magmatic–hydrothermal pulse. Ore-forming fluids evolved non-monotonically from Paleozoic high-temperature magmatic fluids to more heterogeneous crustal, metamorphic, and meteoric–water–influenced systems. Zhengguang and Laozuoshan provide clear evidence for temporally distinct superimposed mineralization. Later hydrothermal reactivation could either remobilize and reconcentrate Au or leach, disperse, and obscure earlier mineralization. Exploration should therefore prioritize reactivated structural corridors where intrusive centers, reactive wall rocks, volcanic basins, and multi-stage alteration overlap.