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The Xiaotongjiapuzi gold deposit is located in the Liaodong gold province, NE China. The deposit is hosted in the metamorphic rocks of the Proterozoic Liaohe Group, consisting of marble, schist, and granulite. Three alteration/mineralisation stages were identified, namely (a) quartz–pyrite, (b) quartz–polymetallic sulfides, and (c) quartz–carbonate. Four fluid inclusion types were distinguished: liquid‐rich two‐phase, gas‐rich two‐phase, CO2‐bearing, and pure CO2. Stage 1 quartz contains liquid‐rich two‐phase inclusions with salinity of 5.9–14.3 wt.% NaCl equiv. and homogenisation temperatures of 311°C–408°C. Stage 2 quartz contains all four inclusion types, of which the liquid‐rich two‐phase, gas‐rich two‐phase, and CO2‐bearing inclusions yielded homogenisation temperatures of 268°C–376°C and salinity of 4.1–13 wt.% NaCl equiv. In stage 3 quartz, only liquid‐rich two‐phase inclusions were found, which contain relatively low salinity (1.6–7.6 wt.% NaCl equiv.) and homogenisation temperatures (201°C–254°C), indicating an H2O–NaCl–CO2 system for ore precipitation. Stage 2 δ18Ow and δD values of quartz minerals are of 0.3‰ to 2.3‰ and −100‰ to −96‰, respectively. Hydrogen and oxygen isotopic compositions indicate that the ore fluids were a mix of magmatic fluid and meteoric water. δ34S values of the metallic sulfides from the Xiaotongjiapuzi deposit range from +4.6‰ to +12.9‰, whilst Pb isotopes show small variations: 206Pb/204Pb = 17.671 to 18.361, 207Pb/204Pb = 15.569 to 15.659, and 208Pb/204Pb = 37.695 to 37.937. Sulfur and lead isotopes suggest that the ore‐forming materials were derived from the Liaohe Group metamorphic rocks and the Triassic granitoids. 3He/4He and 40Ar/36Ar ratios of the fluid inclusions derived of ore‐bearing pyrite ranges from 0.27 to 0.53 Ra and 362.2 to 1113.1, respectively, implying that both mantle‐ and crust‐derived fluids were involved in the gold mineralisation. The Xiaotongjiapuzi deposit could be a mesothermal gold deposit, and the fluid phase separation or immiscibility is the dominant mechanism for the deposition of ore‐forming materials. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The ore fluid was characterized by intermediate temperature, low salinity, CO 2 -rich, and belongs to a H 2 O–NaCl–CO 2 system. • The ore fluids have multiple sources, including magmatic fluid, metamorphic fluid and meteoric water. • The ore-forming materials were derived from Triassic granite and metamorphic rocks of the Liaohe Group. Abstract The Baiyun gold deposit is located in the Liaodong peninsula in NE China. The gold orebodies are hosted in the Paleoproterozoic Liaohe Group metamorphic rocks. The alteration/mineralization can be divided into three stages: (I) quartz ± pyrite ± K-feldspar veins, (II) quartz-polymetallic sulfide veins, (III) quartz-carbonate veins. New LA–ICP–MS zircon U–Pb dating suggests all the ore-related porphyries, including monzonite porphyry (224.2 ± 1.3 Ma), quartz porphyry (221.4 ± 1.2 Ma) and diorite porphyry (221.8 ± 1.2 Ma), were emplaced in the Late Triassic. Four types of fluid inclusions (FIs) are identified in the ore-related quartz, i.e., liquid-rich two-phase, vapor-rich two-phase, CO 2 -bearing and pure CO 2 FIs. The ore-forming fluids were likely characterized by medium temperature, low salinity, low density, CO 2 -rich, and belong to the H 2 O–NaCl–CO 2 ± N 2 ± C 4 H 6 system. We propose that fluid phase separation likely caused rapid precipitation of the ore minerals. The C–H–O–Pb isotope data indicate that the ore-forming fluids may have had multiple sources, including magmatic, metamorphic and meteoric fluids. The ore-forming materials may have mainly derived from metamorphic rocks of the Proterozoic Gaixian Formation, and minor from the Triassic intermediate-felsic rocks. The He–Ar isotope data indicate that the ore-forming fluids were mainly crust-derived. We conclude that the Baiyun gold deposit is an orogenic-type system formed during the Late Triassic North China-Yangtze continent-continent collision. [ABSTRACT FROM AUTHOR]

• The Wulong gold deposit was formed in the early Cretaceous. • The ore-forming fluids could be magmatic in origin. • The deposit was formed during lithospheric thinning of the eastern North China Craton. The Wulong deposit is the largest quartz vein-type gold deposit in the eastern Liaoning Province of China. The gold ore bodies are hosted by Mesozoic biotite-granites. The mineralization occurs as veins with lenticular shapes. Laser-ablation-ICP–MS zircon U–Pb dating was used to date the biotite-granite, granite porphyry, and fine-grained diorites at the Wulong deposit, yielding ages of 155.4 ± 0.9 Ma, 154.2 ± 1.2 Ma, and 123.1 ± 0.9 Ma, respectively. A sericite sample from the gold ore yields a 40Ar–39Ar plateau age of 122.8 ± 0.8 Ma (MSWD = 0.09). The calculated δ18O w values for the quartz range from 4.8% to 8.6% and the δD W values of fluid inclusion waters in quartz vary from −98% to −77%. The H–O isotope data indicates that ore-forming fluids could be of a magmatic origin. The δ34S values of metallic sulfides range from +1.1% to +2.4%, with an average of +1.8%, suggesting that the sulfur is derived from a magmatic source. The 3He/4He ratios of fluid inclusions in pyrite range from 0.36 to 0.65 Ra with an average of 0.50 Ra. The mantle helium involved in the ore-forming fluid ranges from 3.9% to 7.2%, indicating a crustal fluid source. The Wulong gold deposit was formed at ca. 120 Ma and it has a genetic association with contemporaneous fine-grained diorite. The Wulong deposit was formed during lithospheric thinning of the eastern North China Craton during the early Cretaceous. [ABSTRACT FROM AUTHOR]