The Shipenggou gold deposit is situated in the northeastern margin of the North China Craton (NCC), adjacent to the Jiapigou ore district. This study integrates pyrite Rb-Sr geochronology, H-O isotope analyses, in-situ sulfur isotope analyses of sulfides, and pyrite trace element analyses to constrain the genesis and age of the Shipenggou deposit, thereby advancing our understanding of regional gold metallogenic processes. Ore bodies in the Shipenggou deposit primarily occur as gold-bearing quartz veins hosted within the biotite-plagioclase gneiss of the Sandaogou Formation, structurally controlled by NEE-and NNE-trending brittle-ductile structures. The delta 18OH2O (-3.6 to-6.2%o) and delta D (-87.3 to-69.2%o) values suggest that the initial ore-forming fluids were predominately derived from a magmatic source, with subsequent meteoric water incursion during the late stages of mineralization. Sulfur isotope data of sulfides (delta 34S = 4.62 to 8.19%o) indicate that sulfur is primarily sourced from a mantle-derived reservoir, with incorporation of crustal components through wall-rock assimilation. Pyrite initial 87Sr/86Sr signatures (0.71026 to 0.71044) imply a hybrid source for the ore-forming materials involving both mantle and crustal components. Variation in pyrite trace element compositions reflect a gradual decrease in temperature and a slight increase in oxygen fugacity (& fnof;O2) of hydrothermal fluids throughout the mineralization process, although conditions remained predominantly reducing. Pyrite samples from polymetallic sulfide-quartz veins yield a well-constrained Rb-Sr isochron dating result of 165 +/- 5 Ma, precisely determining the gold mineralization age in the Shipenggou deposit. These findings indicate that the Shipenggou deposit is of magmatic-hydrothermal origin, genetically linked to the Middle Jurassic subduction of the Paleo-Pacific Plate.

The Liulong gold deposit (5.7 t Au reserves @ 8.4 g/t), located in the eastern Nanling Metallogenetic Belt (NMB), represents the first medium-scale deposit discovered in the southern Jiangxi Province. Gold mineralization is predominantly hosted within Neoproterozoic Shangshi Formation metasedimentary tuffs and controlled by nearly NS-trending secondary fractures. The deposit comprises polymetallic sulfide-quartz veins and auriferous altered rocks, with four hydrothermal stages identified: (I) quartz-sericite-minor sulfide, (II) quartz-pyritearsenopyrite, (III) polymetallic sulfides-gold minerals-quartz-siderite, and (IV) quartz-calcite. The Rb-Sr dating of pyrite and sphalerite yielded an isochron age of 156.7 +/- 2.3 Ma (MSWD = 1.4), contemporaneous with ca. 163-157 Ma intermediate-acidic granitic intrusions near the mining district. The ore-forming fluids exhibit moderate to low temperatures, low salinity, and a H2O-NaCl-CO2 system containing variable CH4 contents. From Stage II to Stage IV, the fluid inclusions (FIs) homogenized at temperatures of 308-370, 187-307, and 138-197 degrees C, respectively, with corresponding salinities of 1.9-6.2, 1.7-8.4, and 1.4-3.2 wt% NaCl equiv., respectively. Fluid boiling was the primary mechanism for the precipitation of gold and other metals. The delta DH2O values of FIs in quartz from different stages are relatively constant (-50.2 to -69.9 %o), whereas calculated delta 18OH2O values show variation: 8.31-9.81 %o (Stage II), 3.65-4.85 %o (Stage III), and - 8.92 %o (Stage IV), respectively. These H-O isotope data suggest an initial magmatic fluids source, with meteoric water becoming dominant during the later mineralization stage. Sulfides exhibit narrow in situ delta 34S values (- 0.85-2.00 %o), yielding an estimated delta 34S value of -1.03 %o for the initial ore-forming fluids, calculated with the sulfur isotopic fractionation of pyrite-sphalerite pairs. Sulfide Pb isotopic ratios (206Pb/204Pb = 17.644-17.996, 207Pb/204Pb = 15.539-15.611, and 208Pb/204Pb = 38.176-38.413) differ from regional gold deposits in the NMB and plot between Yanshanian granites and Neoproterozoic ore-hosted strata rocks with a linear trend, indicating significant metal contributions from both Late Jurassic granites and Neoproterozoic strata. Therefore, the Liulong deposit is classified as a magmatic-hydrothermal gold deposit genetically linked to Late Jurassic intermediateacidic granites, providing insights for exploring similar deposits in southern Jiangxi.

Identification of mineralization-related geochemical anomalies is a key step for geochemical exploration in an area with a complex geological background. In this study, a combined model integrating robust factor analysis and robust regression analysis was developed for distinguishing the stream sediment geochemical anomalies. The concentrations of major rock-forming oxides were applied to a robust factor analysis for identifying element associates and principal factors representing different lithological types. Subsequently, these factors were used as independent variables in a robust regression analysis to model the background variations of trace metals. The resulting geochemical residuals, representing the discrepancy between measured and predicted values, were then defined as new geochemical exploration indicators. The 1:200,000 stream sediment geochemical data in the Yinkeng Orefield were analyzed, and the results revealed that the lithologic background is characterized by the first three principal factors, including F1 (Al2O3-Na2O-K2O), F2 (CaO-MgO) and F3 (MgO-Fe2O3), which represent intermediate–acid magmatic plutons, carbonate and other calcium-magnesium sedimentary rocks, and basic–ultrabasic intrusive rocks, respectively. Among the six trace elements (Au, Ag, Pb, Zn, W, Sn), the concentrations of Pb and Sn show strong positive correlation with F1, whereas those of Zn are influenced by both F1 and F3. Compared to the measured values, the residuals more effectively identify mineralization-related anomalies, as evidenced by a stronger spatial correlation between high residual areas and the known ore deposits, indicating that the proposed model is a viable technique for geochemical exploration in geologically complex areas.

The Niuxingba deposit, a recently discovered large-scale Ag-Pb-Zn deposit in the eastern Nanling metallogenic belt (NMB), South China, contains proven metal reserves of 124,982 tons Pb, 291,585 tons Zn, and 488.3 tons Ag. The orebodies mainly consist of vein-like sulfides, and occur in the volcanoclastic sedimentary rocks of Neoproterozoic Kuli Formation. The Ag-Pb-Zn orebodies yielded a sphalerite Rb-Sr isochronal age of 158.6 +/- 2.2 Ma. Zircon LA-ICP-MS U-Pb dating revealed that the ore-related granodiorite porphyry was formed at 160.7 +/- 1.9 Ma, suggesting the Late Jurassic magmatism and mineralization. Ore-related granodiorite porphyry at Niuxingba exhibits light hydrothermal alterations with loss on ignition values (LOI) of 4.62 %-7.07 %. The fluid immobile elements indicate that it is geochemically akin to the granitoids linked to Pb-Zn polymetallic mineralization in the NMB, and genetically belongs to weakly peraluminous high-K I-type granite. The Hf isotope compositions indicate that the magma probably originated from the partial melting of low crustal basement, with a minor contribution from juvenile crustal melts. H-O isotope characteristics indicate a magmatic source for ore- forming fluids, with less input from meteoric water. Additionally, the narrow delta 34S values (-3.8 %o to-0.3 %o) of sulfides from mineralization stages II and IV are consistent with other Pb-Zn polymetallic deposits in the ShiHang Belt, suggesting a magmatic source. The Pb isotopic data indicate the ore-forming materials at Niuxingba derived from a crust-mantle mixing source. Combined with the regional tectonic setting, we propose that the Niuxingba deposit is a magmatic-hydrothermal deposit that formed in an extensional setting related to PaleoPacific plate subduction.

The Xiong’ershan district is situated on the southern margin of the North China Craton (NCC) and located within the Qinling–Dabieshan Orogen’s orogenic zone. It is adjacent to the XiaoQinling mining district and exhibits very favorable geological conditions for mineralization, as the district contains numerous gold deposits, positioning it as one of the key gold-producing areas of China. The Miaoling gold deposit is a hydrothermal deposit and is controlled by the Mesozoic nearly NS-trending fault. The ore bodies are hosted in the Mesoproterozoic Xiong’er Group of the Changcheng System of volcanic rocks, with reserves reaching large-scale levels. Pyrite is the main gold-bearing mineral and can be classified into four generations: early-stage fine- to medium-grained euhedral to subhedral cubic pyrite (Py1); medium- to coarse-grained euhedral to subhedral cubic granular pyrite in quartz veins (Py2a); fine-grained subhedral to anhedral disseminated pyrite in altered rocks (Py2b); and late-stage anhedral granular and fine-veinlet pyrite in later quartz veins (Py3). Through in situ trace element analysis of the pyrite using LA-ICP-MS, a positive correlation between Au and As was observed during the main mineralization stage; gold mainly exists as a solid solution within the pyrite lattice, and the ablation signal curve reflecting the intensity of trace element signals showed that gold also occurs as micron-scale mineral inclusions. The trace element content suggested a gradual increase in oxygen fugacity from Stage 1 to Stage 2, followed by a decrease from Stage 2 to Stage 3. The Co/Ni values in the pyrite (0.56 to 62.02, with an average of 12.34) exhibited characteristics of magmatic hydrothermal pyrite. The in situ sulfur isotope analysis of the pyrite using LA-MC-ICP-MS showed δ34S values of 4.24‰ for Stage 1, −6.63‰ to −13.79‰ for Stage 2, and −4.31‰ to −5.15‰ for Stage 3. Considering sulfur isotope fractionation, the δ34S value of the hydrothermal fluid during the main mineralization stage was calculated to be between 0.31‰ and 2.68‰.

The Yuerya gold deposit, a representative gold deposit associated with Mesozoic granites in the eastern Hebei region, is located in the eastern Hebei-western Liaoning gold ore-concentrated area, the northern margin of the North China Plate. The orebody is mainly preserved in the Yanshanian granite and its contact zone with the carbonate rocks of the Gaoyuzhuang Formation, and the main ore mineral is pyrite. Based on the pyrite texture, geochemical characteristics of the in-situ trace element analysis, and sulfur isotope, the pyrite in the mining area is classified into five generations (Py1, Py2, Py3, Py4a, and Py4b). Five generations of pyrite all have an average Te/Se ratio > 1, and their average Co/Ni ratios are 1087.27, 43.97, 4.17, 12.62, and 4.99, respectively, indicating that the ore-forming fluid predominantly originates from magmatic-hydrothermal. In-situ sulfur isotopic analysis using LA-MC-ICP-MS shows that the delta S-34 values of the five generations of pyrites ranged from 0.3 parts per thousand to 9.6 parts per thousand; the mean values are 3.8 parts per thousand (Py1, n = 4), 4.2 parts per thousand (Py2, n = 10), 2.6 parts per thousand (Py3, n = 18), 4.0 parts per thousand (Py4a, n = 20) and 4.6 parts per thousand (Py4b, n = 29), respectively. Approximately 32 % of the results exceed 5.0 parts per thousand, surpassing the values indicative of a magmatic-hydrothermal source. Thermodynamic simulations reveal that the fluctuations in the oxidation state of the ore-forming fluid is not the predominant cause of delta S-34 enrichment in the pyrite. Our studies suggest that sulfur is primarily derived from mantle-crust mixtures, with some contributions from the wallrock of the Gaoyuzhuang Formation. The results from LA-ICP-MS trace element analysis of pyrites reveal a significant enrichment of As-Bi-Te-Tl alongside Au in the ore-forming fluid. Additionally, the results of ore-forming elements in three typical cross sections of different wallrocks in the mining area also show that Au, Ag, As, and Pb are closely related. Therefore, it is considered that the over-enrichment of As could be an important factor leading to the precipitation of Au. Pyrite undergoes expansion of the mineral lattice parameters or lattice dislocation due to the substitution of S with As, creating space for the growth of solid-solution Au. Subsequently, some of the solid-solution Au within pyrite is liberated through internal oscillations, forming the visible gold particles.

The Wunugetu deposit, a large-scale porphyry copper–molybdenum deposit, is located in the southern Erguna block. Its ore bodies are primarily found within monzogranites, granite porphyries, and biotite monzogranites. Additionally, the deposit contains late-stage intrusive dykes of rhyolitic porphyries. This study examined the deposit’s monzogranites and rhyolitic porphyries using lithogeochemistry, zircon U-Pb dating, and Hf isotopic analysis. The main findings include: (1) Zircon U-Pb dating showed that the monzogranites formed around 209.0 ± 1.0 Ma, whereas the rhyolitic porphyries in the northern portion formed around 170.49 ± 0.81 Ma, suggesting magmatic activity in the deposit spanned from the Late Triassic to the Middle Jurassic. (2) The monzogranites exhibited high silicon content (73.16–80.47 wt.%) and relatively low aluminum content (10.98–14.37 wt.%). They are enriched in alkalis (content: 3.42–10.10 wt.%) and deficient in magnesium and sodium, with aluminum saturation indices (A/CNK) ranging from 1.1 to 2.9. In addition, the monzogranites are enriched in large-ion lithophile elements (LILEs) such as Rb, K, and Ba and deficient in high-field-strength elements (HFSEs) like Nb, P, and Ti. (3) The monzogranites have low Zr + Nb + Ce + Y contents of (151.3–298.6 ppm) × 10−6 and 10,000 × Ga/Al ratios varying between 1.20 and 2.33, suggesting that they are characteristic of I-type granites. (4) Positive zircon εHf(t) values ranging from +0.3 to +7.6 in both rhyolitic porphyry and monzogranite samples, increasing with younger emplacement ages, imply that the deposit’s rocks originated from magmatic mixing between mantle-derived mafic magmas and remelts of the juvenile crust. Considering these results and the regional geological evolution, this study proposes that the Wunugetu deposit was formed in an active continental margin setting and was influenced by the Late Triassic–Middle Jurassic southeastward subduction of the Mongol-Okhotsk Ocean.

Nickel (Ni) and Cobalt (Co) deposits are important mineral resources, and China is the largest consumer of these resources. Magmatic, hydrothermal, sedimentary, and meta-sedimentary ore-bearing rocks are the most significant Co-Ni deposit types in China, accounting for 98% of the Co production. Thus, exploring the Chinese Co-Ni resources and reserves is beneficial for promoting its economic development. We have analyzed the metallogenetic geologic model and the physical characteristics of the rocks and ores of magmatic Co-Ni sulfide and hydrothermal Cu-Co deposits and the sedimentary and meta-sedimentary rocks that host the Cu-Co ore deposits to develop an effective geophysical exploration technology system. For magmatic deposits, the small ore-forming intrusion is the main detection target; in general, gravity, magnetic, and seismic exploration and artificial-source electromagnetic methods are widely used to determine the precise location of the ore-forming intrusion. For hydrothermal deposits, ore-controlling structures and favorable positions for mineralization (e.g., alteration belts) are the main exploration targets, and the combination of hyperspectral remote sensing, gravity, magnetic-excitation, chemical prospecting, and artificial-source electromagnetic detection techniques can help locating such ore body types. For sedimentary and meta-sedimentary ore-bearing deposits, a combination of soil debris geochemical exploration measurement, induced polarization (IP) scanning, gravity method, IP sounding, and the transient electromagnetic method has been used to scan and locate the ore-controlling and ore-bearing layers. Finally, upon selecting the Xiarihamu magmatic Co-Ni deposit in the East Kunlun orogenic belt as our study area, we have conducted controlled-source electromagnetic exploration and obtained reliable results. Our study can serve as a reference for determining the most effective geophysical technique for the exploration of Cu-Ni-Co deposits in China.

The Guojiagou Pb-Zn deposit is located in Li County, Gansu Province, northwestern China. The ores consist of skarn and vein types, with the skarn type occurring at the contact zone between granodiorite and marble, and the vein type hosted in the extension faults within the Triassic Huashiguan Formation limestone. Granodiorite samples from the Weijiazhuang pluton show high ratios of Sr/Y (32.25-43.44) and (La/Yb)N (15.7-16.5), small Eu anomalies (delta Eu = 0.73-0.80), high concentrations of Mg# (57.6-64.2), Cr (100-110 ppm), and Ni (15.9-16.6 ppm), abundant mafic micro-granular enclaves, and have zircon epsilon Hf(t) values of -1.9 to -4.6 and TDM2 of 1149.6 to 1285 Ma. This suggests that the Weijiazhuang granodiorites were generated by the partial melting of the MesoProterozoic high-K basaltic lower crust with the addition of mantle-sourced melts. The ore-forming process can be subdivided into five stages: prograde skarn (stage I), retrograde skarn (stage II), quartz-sulfide (stage III), sphalerite-calcite (stage IV), and quartz-calcite (stage V). The delta 13C values range from -5.1 to -1.3 %o and delta 18O values range from -4 to 18.6 %o in calcites, suggesting a mixed source of magma, limestone, and pore or basinal water for CO32- . The delta 34S values (6-7.7 %o) of sulfides indicate that sulfur mainly originated from magma, with a minor contribution from host limestone. The Pb isotopes of sulfides from stages III and IV (208Pb/204Pb = 38.176-39.218, 207Pb/204Pb = 15.889-15.678, and 206Pb/204Pb = 18.147-18.903) showed mixed sources of crust and mantle. The Weijiazhuang pluton and Guojiagou Pb-Zn deposit yield ages of 220 +/- 1.8 Ma (MSWD = 0.35) and 213 +/- 3.0 Ma (MSWD = 1.5), respectively, obtained by zircon and garnet LA-ICP-MS U-Pb analysis. These results indicate that the Guojiagou Pb-Zn deposit formed in a syn-collisional tectonic regime during the Late Triassic. Based on the data presented in this study and previous research on mineralization in the eastern West Qinling Orogen, we conclude that the Guojiagou Pb-Zn deposit is a typical skarn-type deposit and that Pb-Zn mineralization in the eastern West Qinling Orogen is closely related to Triassic magmatism, which provided not only thermal energy but also ore-forming materials and fluids.

黑龙江东部那丹哈达地体位于锡霍特 阿林造山带中部西缘,中生代以来发生了剧烈的构造—岩浆—成矿作用,发育有热泉型、火山热液型、浅成低温热液型以及矽卡岩型等铜金矿床.笔者等在详细的野外地质调查基础上,对四平山、先锋北山、258高地和跃进山4个典型矿床的成矿岩体进行主量元素、稀土、微量元素地球化学特征分析以及锆石U-Pb年代学研究,旨在探讨研究区燕山期铜金成矿构造背景与成矿模式.研究结果表明,四平山金矿床、先锋北山金矿床、258高地金矿床和跃进山铜金矿床成矿岩体的LA-ICP-MS锆石U-Pb年龄分别为122.5±1.1 Ma、1 17.0±0.4 Ma、116.9±0.8 Ma和115.7±1.1 Ma,矿床成矿时代属于早白垩世晚期.4个矿床的成矿岩体具有相似的岩石地球化学特征,属于中分异Ⅰ型花岗岩,岩浆来源于地壳物质部分熔融源区,形成于碰撞后构造背景.结合矿床地质背景、锆石U-Pb年代学特征、地球化学特征以及区域构造演化,笔者等认为四平山金矿床、先锋北山金矿床、258高地金矿床和跃进山铜金矿床的成矿时代基本一致,成因均与燕山期中酸性岩浆相关,属于同一成矿系列,铜金成矿作用与古太平洋板块俯冲作用密切相关.

The Bajiazi gold deposit, located within the southeastern Jiapigou gold ore belt (JGB) along the northeastern corner of the North China Craton (NCC), contains > 6 tons of gold at an average grade of 24 g/t. >20 total auriferous quartz veins are hosted in the Neoarchean basement gneiss and amphibolite and are spatially and temporally associated with Mesozoic intermediate-acid dikes. The distribution of the gold orebodies is mainly controlled by NNE-trending brittle-ductile shear zones and faults. Three hydrothermal stages were identified, namely, quartz-pyrite (stage I), quartz-gold-polymetallic sulfide (stage II), and quartz-carbonate (stage III). Three types of fluid inclusions (FIs) were identified: H2O-NaCl (W-type), CO2-H2O (C-type), and pure CO2 (PC -type) FIs. From stage I to stage III, the FI suite changes from W-type and C-type in stage I to all three types in stage II and to only W-type in stage III. The FIs in the quartz of stages I to III mainly homogenized at temperatures (Th) of 283-395 degrees C, 183-287 degrees C and 116-186 degrees C, respectively, with salinities of 3.87 to 13.01 wt% NaCl equiv, 4.65 to 18.55 wt% NaCl equiv, and 3.83 to 9.68 wt% NaCl equiv, respectively. The ore-forming fluids of the Bajiazi gold deposit evolved from a H2O-NaCl-CO2 system in stages I and II to a H2O-NaCl system in stage III. Fluid immiscibility is an important mechanism leading to rapid precipitation of sulfides and gold. H-O-S isotope signatures indicate that the initial ore-forming fluids and materials were originally derived from magmatic sources. Electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) data on pyrite grains show that abundant gold mineralization occurred in the middle hydrothermal stage. The high Co/Ni ratios of pyrite are consistent with a magmatic-hydrothermal origin. The results, com-bined with previous regional studies, indicate that the Bajiazi gold deposit is a mesothermal magma-tic-hydrothermal lode gold deposit.

The Sipingshan gold deposit is intermediately sized and located in the eastern Wandashan Terrane. It has attracted much attention for its uncommon genetic type of hot spring. Gold orebodies mainly occur in the upper and lower siliceous rocks, siliceous cemented breccia is found between the upper and lower siliceous rocks, and silicified rhyolite porphyry is observed below the lower siliceous rocks. Two main mineralisation periods (i.e. exhalative sedimentation and hydrothermal superimposition) have been identified at Sipingshan based on mineral paragenesis and crosscutting vein relationships. In this study, analyses of whole-rock geochemical compositions, pyrite Rb-Sr age, zircon U-Pb-Hf contents, and S-Pb-O-H isotopes were conducted to determine the Au mineralisation time and ore genesis of this deposit. The ore-bearing siliceous rock revealed weighted mean 206Pb/238U ages of 121.8 +/- 1.1 Ma and 117.6 +/- 1.0 Ma, representing the mineralisation age of the exhalative sedimentation period. The Rb-Sr isochron age of pyrites (106 +/- 3 Ma) was consistent with the Au-Cu mineralisation age in the Wandashan area and represented magmatic-hydrothermal mineralisation. The siliceous rocks were characterised by high SiO2 (97.92-99.18 wt%), low TiO2 (0.01-0.03 wt%), low Al2O3 (0.22-0.55 wt %), negative delta Ce (0.78-1.00), positive delta Eu (1.12-4.04), and low Sb, As, Cs, Cd and Li contents, indicating the genesis of hydrothermal sediments. The O-H isotope results suggested that the ore-forming fluids were mainly derived from magmatic water and mixed with meteoric water in the later stage. The delta 34S values of pyrites from the siliceous rocks (-25.8 to -8%o) indicated a biogenic sulfur-dominated source, corresponding to the exhalative sedimentation period. The delta 34S values of pyrites (9.8 to 29.7 %o and -1.9 to -4.7 %o) formed in the magmatic-hydrothermal period indicated that sulfur was most likely derived from sedimentary rock and magmatic sulfur sources. The Pb isotope data also implied a mixture of upper crust and mantle sources. Therefore, we propose that the Sipingshan gold deposit is a continental exhalative sedimentation-type gold deposit superimposed by later magmatic-hydrothermal fluids, and formed during the subduction of the Paleo-Pacific Plate during the Early Cretaceous.

Coesite-bearing eclogites and garnet-bearing granitic gneisses from the Yangkou area in the middle portion of Sulu ultrahigh pressure (UHP) metamorphic belt records three stages of metamorphism: I) Prograde to peak stage, II) Early retrograde stage, and III) Late retrograde stage. The prograde stage is recorded in the core to mantle in garnet and Si (3.38–3.43) in phengite in eclogite that has the assemblage of Grt-Omp-Amp-Phg-Lws (+ Qtz + Rt + H2O), and the P-T conditions are constrained at 25–27 kbar and 585–595°C. Stage II is constrained by Xgr (0.48–0.55) in garnet from mantle to rim, XAn (0.009–0.011) from mantle to rim in plagioclase of granitic gneiss, and the P–T conditions are estimated to be 29–35 kbar and 865–990°C with the mineral assemblage of Grt-Bt-Pl-Phg-Liq (+ Qtz/Coe). Stage III is constrained by two P-T ranges: mineral assemblage of Grt-Ep-Bt-Pl-Phg-Liq (+ Qtz) and Xgr (0.45–0.72) from mantle to rim in garnet in granitic gneiss constrained an earlier P-T range of 22–23 kbar and 800–820°C, while Xgr (0.34–0.39) and Xpy (0.16–0.18) from mantle to rim in garnet in eclogite in the assemblage of Grt-Omp-Amp-Phg-LL (+ Qtz + Rt + H2O) constrained a later P-T range of 17–18 kbar and 675–690°C. The formation and evolution of these assemblages have important implications for the generation and differentiation of continental crust through the operation of plate tectonics. The data suggest that both mafic and granitic rocks in the Yangkou area subducted to a depth of more than 115 km and underwent UHP metamorphism. The three stages of metamorphism in the study area are consistent with the regional well-established metamorphic evolution history, from UHP eclogite facies, through HP/HT eclogite facies, to amphibole eclogite facies with the timing of 230, 225, and 195 Ma, respectively.

The Yawan Sb deposit is a large deposit located in the Xihe County, Gansu, northwestern China. Ore bodies are hosted in the Triassic limestone and are controlled by the NE-trending faults, occurring as lamellar, lenticular, veined, and lentil. Based on the cutting relationship between veins and mineral assemblages, the ore-forming process can be divided into four stages: I) pyrite + stibnite + milky quartz stage, II) stibnite + pyrite + gray-black cryptocrystalline quartz stage, III) stibnite + calcite + fluorite stage, and IV) clear and colorless calcite stage. The delta 34S values (-2.5 %o to 5.8 %o) of sulfides from stage II are similar to those associated with magmatic systems, but significantly different from the values (delta 34S =-12.8 %o to 18.8 %o) of pyrites from strata, suggesting that magmatic sulfur was the source for S2-in stage II. The delta 34S values (-9.5 %o to-7.5 %o) of stibnites from stage III are depleted in 34S relative to those of stage II, probably due to the increasingly mixing of meteoric water and SO42-from the strata. The Pb isotopes of sulfides from stage II and III (206Pb/204Pb = 17.745-19.176, 207Pb/204Pb = 15.478-15.711, 208Pb/204Pb = 37.7-38.742) show a mixed source of crust and mantle. The delta 13C and delta 18O values of calcites range from-0.84 %o to 3.94 %o and from 4.74 %o to 13.24 %o, respectively, indicating that the ore-forming fluids originated from magmatic water, but influenced by water-rock interaction and meteoric water in the late stage. The Sm-Nd isochron age of five calcite simples from stage III is 199.9 +/- 1.7 Ma (MSWD = 1.6) with initial epsilon Nd values of-8.4, indicating that Yawan Sb deposit formed in the Late Triassic to Early Jurassic. On the basis of the data obtained in this paper, we consider that the Yawan Sb deposit is a distal magmatic-hydrothermal deposit formed during the transitional tectonic regime from the syn-collision to post-collision. Combined with previous studies, future exploration should focus on the distal magmatic-hydrothermal Sb deposits controlled by faults around concealed granites, and skarn-type deposits also need attention in Yawan-Daqiao district.

The Xiaobeigou gold deposit (>20 t @ 17.36 g/t) is located in the Jiapigou gold district (JGD), Northeast China, representing a large-sized quartz vein-type gold deposit hosted by Neoarchean basement gneiss and is related to Mesozoic intrusions in space and time. Four hydrothermal stages were identified from early to late, namely, (1) barren quartz stage, (2) quartz-pyrite stage, (3) gold-quartz-polymetallic sulfide stage, and (4) quartz-carbonate stage. Three main types of fluid inclusions (FIs) have been identified: water-rich (H2O-NaCl; W-type), mixed aqueous-carbonic (CO2-H2O-NaCl; C-type) and pure carbonic (CO2; PC-type) FIs. The early-stage quartz contains W- and C-type FIs that yield moderate homogenization temperatures (270-379 degrees C) and moderate-low salinities (4.82-17.87 wt% NaCl equivalent). The main-stage quartz grains contain all three types of FIs that yield medium-low temperature (179-263 degrees C) and moderate-low salinity (2.82-9.86 wt% NaCl equivalent). Only Wtype FIs are recognized in late-stage quartz grains, which have low temperatures (133-183.C) and low salinities (1.91-7.73 wt% NaCl equivalent). The initial ore-forming fluid of the Xiaobeigou gold deposit was a moderate homogenization temperature and moderate-low salinity CO2-H2O-NaCl +/- CH4 +/- N-2 hydrothermal fluid system. Fluid immiscibility is the main mechanism leading to the precipitation of gold and other metal sulfides. The H-O isotopic values (delta(OH2O)-O-18 = 6.87 to 5.90%; dD = 102 to 78%) and composition of the quartz suggest that the initial ore-forming fluids consisted mainly of magmatic water mixed with meteoric water during the late stage of the mineralization process. The S isotope data (delta S-34 = 3.2 to 4.4%, avg. 3.6%) indicate that the ore-forming materials are magmatic sources. EPMA and LA-ICP-MS data show that a large amount of gold mineralization mainly occurs in the main ore-forming stage. The high Co/Ni ratio indicates that the pyrite may be a magmatichydrothermal source. Taking into account all available data and regional geological history, we suggest that a magmatic-hydrothermal source for the Xiaobeigou gold deposit in the JGD and the ore formation is related to the subduction of the Paleo-Pacific Plate beneath Eurasia.

The Dzhalinda intrusion is closely related to the mineralization of the Kirov gold deposit in the Far East of Russia. Based on the characterization of the petrology, geochemistry, and zircon U–Pb chronology of the Dzhalinda intrusion, this paper investigates the age, geochemical characteristics, and tectonic setting of the intrusion. The main rock is granodiorite. Petrological and geochemical analysis results show that the rocks have quartz (20%), potash feldspar (15%), plagioclase (60%), and biotite (3%), and belong to the calc-alkaline series. Trace element and rare earth element (REE) abundances suggest that the magma may primarily have originated from above the oceanic crust subduction of oceanic lithosphere mantle partial melting, wedge, and contamination by crustal material. Zircon U–Pb dating indicates that the Dzhalinda intrusion was formed in the Early Cretaceous, 125.44 ± 0.69 Ma. Combined with regional data, the Dzhalinda intrusion is considered to be formed by the subduction of the ancient Pacific plate with the Eurasische plate. Mineralization of the Kirovskoe gold deposit was the filling of the hydrothermal fluid along the NNE- and NW-trending faults following the magmatic period of the Dzhalinda intrusion.

The Pb–Zn-Ag–Cu-Sn-Fe-Mo metallogenic belt in the southeastern Inner Mongolia is the most important polymetallic concentration area in China. Geologists have conducted detailed studies on typical polymetallic deposits, but the distribution feature and ore-controlling factors of the overall deposits in the study area are still unclear. In this research, geochemical and geochronological characteristics, including major and trace element analysis, zircon U–Pb dating, sulfur isotope, and magnetic data, were combined with regional geological background to explore the formation mechanism of deposits. The results show that metallogenic material source, geological structure, the Permian strata, and ore-forming materials in the wall rock and magmatic rock are the major ore-controlling factors in the southeastern Inner Mongolia. Specially, the main mineralization periods in the study area were the Late Jurassic and Early Cretaceous, and the ore-forming minerals were mainly related to the acidic magma activity. The elements in strata provided a source of minerals as well. In addition to the magmatism which plays a key role on the spatial distribution of deposits, the combined control of the regional deep faulted structural belts, the newly-born structures, and the NE-trending fold structures of the Permian strata makes the deposits present belts in the northeast, clusters in the northwest, and patches at the intersection. A systematic summary of metallogenic characteristics, combining geological background with geochemical and geochronological information, yields important practical significance for future regional prospecting.

The Chang’anpu Molybdenum deposit occurs in the monzogranite intrusions in the Lesser Khingan Mountains-Zhangguangcai Mountains metallogenic belt. Previous work focused on the study of deposits, including geological characteristics, mineralization time, S-Pb isotope, etc. However, systematic petrogeochemical study of monzogranite intrusion and comparative analysis with other porphyry deposits in the region are lacking. Three monzogranite dating samples yield LA-ICP-MS zircon weighted mean 206Pb/238U ages of 174.7 ± 1.3 Ma, 174.9 ± 1.4 Ma, and 174.3 ± 1.8 Ma, respectively, indicating that the magmatism occurred in the middle Jurassic of Mesozoic. The 14 monzogranite samples show alkali rich and relatively high silica content (up to 84.39%) with the differentiation index (DI) ranges from 86 to 96, showing that monzogranite have been subjected to fractional crystallization during its evolution; the depletion of Ba, Sr, P, Nb, Ti, and Eu also indicates that the rock has undergone crystallization fractionation, the monzogranite belong to the highly fractionated I-type. Positive εHf(t) values (6.72–8.85) and young TDM2 (551–673 Ma) of the monzogranite indicate that the formation of Chang’anpu monzogranite intrusion is related to the partial melting of juvenile lower crust, originated from the Mesoproterozoic depleted mantle. The magmatism and related Mo mineralization in the Chang’anpu deposit occurred in an active continental margin setting associated with westward subduction of the Paleo-Pacific plate beneath the Eurasian plate.

下嘎来奥伊铅锌矿位于黑龙江省西北部,大地构造位置位于额尔古纳地块额木尔山隆起带南缘与大兴安岭火山岩带北缘交切部位的西段.矿体主要产于中酸性浅成侵入岩与新元古界—下寒武统倭勒根群吉祥沟组大理岩接触带,是一个以铁、铅、锌、钼矿为主的矽卡岩型矿床.通过野外工作和室内观察将其成矿期划分为2期5个阶段:①矽卡岩期:干矽卡岩阶段、湿矽卡岩阶段(形成富集的磁铁矿)、氧化物阶段(形成少量辉钼矿),②石英-硫化物期:早硫化物阶段(形成部分辉钼矿)、晚硫化物阶段(主要形成闪锌矿、方铅矿等铅锌硫化物).结合成矿地质背景、矿区物化探特征,得出成矿控制因素为:①吉祥沟组大理岩及片岩在成矿过程中提供了部分成矿物质,②花岗斑岩、花岗闪长岩、细粒花岗岩等中酸性岩体在侵入过程中提供了成矿物质和能量,③矿区中部复式褶皱构造及北东向和北西向断裂是区内的主要控矿构造.在GIS平台上开展综合信息成矿预测,共圈出2处找矿预测区,指出了今后的找矿方向.这些认识对矿区及外围找矿工作具有重要的指导意义,为进一步开展深部找矿和相关理论研究提供了重要依据.