The Jinchang gold–copper deposit is located in Eastern Heilongjiang Province, Northeastern China. The orebody comprises primarily hydrothermal breccias, quartz veins, and disseminated ores within granite, diorite, and granodiorite. Three paragenetic stages are identified: early quartz–pyrite–arsenopyrite (Stage 1), quartz–pyrite–chalcopyrite (Stage 2), and late quartz–pyrite–galena–sphalerite (Stage 3). Gold was deposited during all three stages and Stage 1 was the major gold-producing stage. Copper is associated with the mineralization but has low economic value. Fluid inclusions (FIs) within the deposit are liquid-rich aqueous, vapor-rich aqueous, and daughter-mineral-bearing types. Microthermometric data for the FIs reveal decreasing homogenization temperatures (T_h) and salinities of the ore-forming fluids over time. The T_h for Stages 1–3 of the mineralization are 421–479, 363–408, and 296–347 °C, respectively. Stage 1 fluids in vapor-rich and daughter-mineral-bearing inclusions have salinities of 5.7–8.7 and 49.8–54.4 wt% NaCl equivalent, respectively. Stage 2 fluids in vapor-rich, liquid-rich, and daughter-mineral-bearing inclusions have salinities of 1.2–5.4, 9.5–16.0, and 43.3–48.3 wt% NaCl, respectively. Stage 3 fluids in liquid-rich and daughter-mineral-bearing inclusions have salinities of 7.9–12.6 and 38.3–42.0 wt% NaCl equivalent, respectively. The estimated trapping pressures are 160–220 bar, corresponding to an entrapment depth of 1.6–1.2 km in the paleo-water table. Oxygen and hydrogen isotope data (δ¹⁸O_V-SMOW = 8.6‰ to 11.4‰; δD_V-SMOW = −92.2‰ to −72.1‰) suggest that the ore-forming fluids were derived from magmatic fluids during the early stages of mineralization and subsequently incorporated meteoric water during the late stages. The sulfide minerals have δ³⁴S_VCDT values of 0.2‰–3.5‰, suggesting that the sulfur has a magmatic origin. The Jinchang deposit is a typical gold-rich gold–copper porphyry deposit.

The Daheyan region, situated in the SW of the Bogda Mountains in eastern Tianshan, is important for understanding the accretionary history of the Central Asian Orogenic Belt. We investigated Carboniferous intrusions from the Daheyan area, SW Bogda Mountains, obtaining new zircon U–Pb ages, whole-rock geochemical data and Hf isotope data for these intrusions. Zircon U–Pb dating indicates that syenogranite, diorite, granodiorite and monzonite of the Daheyan intrusions were all formed during late Carboniferous (311–303 Ma) magmatism. The syenogranite has geochemical characteristics of A-type granites that were mainly sourced from melting of juvenile crust. In comparison, the low-Mg-number diorite intrusion, with tholeiite and metaluminous features, was derived from young crust and mixed some mantle materials. The granodiorite and monzonite are both I-type granites, and are both sourced from the melting of juvenile crust. Based on a comprehensive analysis of previous geochronological, geochemical and isotopic data of magmatic and sedimentary rocks in the Bogda–Harlik belt, we consider that late Carboniferous intrusive rocks of the Bogda Mountains formed in an intra-arc extension related to a continent-based arc setting.