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This study was financially supported by the National Basic Research Program of China (Grant No.2014CB440902) and the National Natural Science Foundation of China (Grant No. 41572072).

The formation of manganese oxides in nature is commonly mediated by microorganisms. In this study, the mineralization of biogenic manganese oxidation mediated by Pseudomanas putida has been experimentally investigated by employing various characterization techniques, including SEM, FESEM, TEM, XRD, and STXM-NEXAFS. The results indicate that Mn2+ ions can be oxidized into Mn (IV) minerals (birnessite and pyrolusite) and Mn(III) minerals (hausmannite and feitknechtite), successively. The primary products (birnessite and pyrolusite) further transformed into hausmannite and feitknechtite under Mn2+ ion-enriched conditions. However, birnessite and pyrolusite are the end-products of the continuous microbial oxidation processes. These biogenic Mn oxides are poorly crystallized, which provides them with a high potential for usage in environmental restoration of contaminated soils and waters contaminated with heavy metals. The approaches employed in this study will also enrich genesis research of biological oxidation of Mn(II) species in nature.

As China's most important gold-producing district, the Jiaodong Peninsula also contains copper, lead–zinc, molybdenum (tungsten), and other nonferrous metal ore deposits, but the space–time and genetic relationships with gold deposits remain uncertain. To investigate the temporal relationship between these nonferrous metal and gold ore deposits, We collected the samples from a number of nonferrous metallic and silver deposits and metallogenetic rock bodies in the eastern Jiaodong Peninsula for isotopic dating. The results show that the Re-Os isotopic model ages of the Lengjia molybdenum deposit in Rongcheng range from 114.5 ± 1.8 Ma to 112.6 ± 1.5 Ma, with an average age of 113.6 ± 1.6 Ma; the LA-ICP-MS 206Pb/238U ages of 33 zircons in the sericitization porphyritic monzogranite that hosts the Tongjiazhuang silver deposit in Rongcheng range between 122 Ma and 109 Ma, with a weighted mean age of 116.04 ± 0.95 Ma; the LA-ICP-MS 206Pb/238U ages of 31 zircons in the copper metallogenic pyroxene monzodiorite that hosts the Kuangbei copper deposit in Rongcheng range from 126 Ma to 106 Ma, with a weighted mean age of 116.6 ± 1.7 Ma; and the LA-ICP-MS 206Pb/238U ages of 19 zircons in the pyroxene monzodiorite surrounding the Dadengge gold and multimetal deposit in Weihai range from 113 Ma to 110 Ma, with a weighted mean age of 111.7 ± 0.6 Ma. All these results indicate that the metallogenic ages of the silver and nonferrous metallic deposits in the Jiaodong Peninsula are in a limited range from 118 Ma to 111 Ma. Previous studies have demonstrated that the isotopic ages of gold deposits in the Jiaodong Peninsula range from 123 Ma to 110 Ma, while Weideshanian magmatism occurred between 126 Ma to 108 Ma. Both these ranges are grossly consistent with the metallogenic ages of silver and nonferrous metallic deposits in this study, suggesting that the large–scale mineralization occurred in the Early Cretaceous when magmatic activities were strong. This epoch may be linked to the lithosphere thinning and the thermo-upwelling extension in eastern China at that time. In addition, field investigation also shows that gold and nonferrous metallic deposits are distributed nearby the Weideshanian granite, with the nonferrous metallic deposits lying within or surrounding the granite pluton and the gold deposits outside the granite pluton. We propose the following mineralization scenario: In the Early Cretaceous, an intensive lithospheric extension induced partial melting and degassing of the metasomatized lithospheric mantle, which resulted in the formation of mantle–derived fluids enriched in metal elements. During the rapid process of magma ascent and intrusion, crust-derived fluids were activated by the magmatic thermal dome and served to further extract ore-forming materials from the crust. These fluids may have mixed with the mantle-derived fluid to form a crust–mantle mixing–type ore-forming fluid. The high-temperature conditions in the center or in contact with the granitic magmatic thermal dome would have been favorable for the formation of porphyry–type, skarn–type, and hydrothermal–vein–type ores, thus forming a series of Mo(W), Cu, and Pb-Zn deposits in the mid-eastern Jiaodong Peninsula. In contrast, the medium- to low-temperature conditions in the periphery of the magmatic thermal dome would have favored the deposition of gold (silver) ores under the appropriate physiochemical and structural conditions. The metallogenic epoch of the molybdenum, copper, and silver deposits, and their spatiot-emporal and genetic relations to the gold deposits, as demonstrated in this study, not only provide important insights to the study of regional metallogeny, our understanding of the metallogenesis of the Jiaodong type gold deposit, and the geodynamic background of the large-scale mineralization in the Jiaodong Peninsula, but also have practical value in guiding the mineral exploration.

The Tiegelongnan deposit is a newly discovered super-large porphyry-epithermal Cu-(Au) deposit in the western part of the Bangong Co-Nujiang metallogenic belt, Tibet (China). Field geology and geochronology indicate that the porphyry mineralization was closely related to the Early Cretaceous intermediate-felsic intrusions (ca. 123–120 Ma). Various epithermal ore and gangue mineral types were discovered in the middle-shallow part of the orebody, indicating the presence of epithermal mineralization at Tiegelongnan. Potassic, propylitic, phyllic and advanced argillic alteration zones were identified. 40Ar/39Ar dating of hydrothermal biotite (potassic zone), sericite (phyllic zone), and alunite (advanced argillic zone) in/around the ore-bearing granodiorite porphyry yielded 121.1±0.6 Ma (1σ), 120.8±0.7 Ma (1σ) and 117.9±1.6 Ma (1σ), respectively. Five hydrothermal mineralization stages were identified, of which the Stage IV pyrite was Rb-Sr dated to be 117.5±1.8 Ma (2σ), representing the end of epithermal mineralization. Field geology and geochronology suggest that both the epithermal and porphyry mineralization belong to the same magmatic-hydrothermal system. The Tiegelongnan super-large Cu-(Au) deposit may have undergone a prolonged magmatic-hydrothermal evolution, with the major mineralization event occurring at ca.120–117Ma.

The Wurinitu Mo deposit is one of the newly found molybdenum deposits in the southwestern part of the late Paleozoic–Mesozoic Erenhot–Dong-Ujimqin metallogenic belt (S-EDMB), Inner Mongolia, China. In the present study, the mineralization age of the Wurinitu deposit is constrained to 137.3 ± 1.3 to 131.9 ± 1.5 Ma based on a combination of the laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) zircon U–Pb dating of the mineralization related fine-grained monzonitic granite and the post-mineralization granite porphyry. The results of zircon Lu–Hf isotopes, combined with the geochemical characteristics of the granites in the S-EDMB, suggest that the Wurinitu Mo deposit was formed in an extensional environment in relation to the subduction of the Paleo-Pacific plate in late Mesozoic. The Wurinitu deposit shares similarities with the classical Climax-type porphyry molybdenum deposits in tectonic setting, mineral assemblages, and metal zonation.

The Duocaima carbonate-hosted Pb-Zn deposit is a newly found large deposit in the southern area of Qinghai Province. In this paper, the characteristics, genesis, significance to Pb-Zn mineralization of the widely developed breccias, and the ore-forming process have been carefully studied based on geological documentation of drilling holes, microscopic observations of petrography and microstructure and some stable isotope measurements. Based on the compositions of the clast and matrix, the breccias can be classified into three types: limestone clasts cemented by marl; limestone clasts with fine-grained calcareous materials; and limestone clasts cemented by hydrothermal calcite. The mineralization in the first type of breccia is weak, whereas it is strong in the latter two types of breccias. According to the locations of occurrence and structural characteristics of the breccias along with the relationship between the breccias and mineralization, part of the limestone clasts that are cemented by marl and outcrop in the contact zone between the Wudaoliang Formation (Nw) and the underlying Jiushidaoban Formation (Pj) are attributed to synsedimentary fault-genetic breccia, whereas the last of the limestone clasts that are cemented by marl and developed in the Jiushidaoban Formation (Pj) are attributed to the breccia generated by karst cave collapse; the limestone clasts with fine-grained calcareous materials and the limestone clasts cemented by hydrothermal calcite are attributed to breccia formed by hydrothermal dissolution. The breccia formed by karst collapse had consistently evolved for a long period of time, while the breccias with other origins were formed around the period of mineralization (i.e., about or slightly later than 20–16 Ma). The breccia generated by karst cave collapse and hydrothermal dissolution are somewhat related; the formation of the breccia from karst cave collapse provided open space for the later mineralization and reaction between hydrothermal fluids and host rocks, and the subsequent strong dissolution by hydrothermal fluids transformed some of the breccia formed earlier by karst cave collapse. Meanwhile, carbonate host rocks with breccias and brecciaed mineralization can be a potential sign of Mississippi Valley Type (MVT) deposits and important indicators for regional mineral exploration. The δ13CV-PDB, δ18OV-SMOW, and 87Sr/86Sr values of hydrothermal calcite in the Duocaima deposit range from 4.3‰ to 7.1‰, 14.9‰ to 20.1‰, and 0.707494 to 0.708185, respectively; the δ13CV-PDB, δ18OV-SMOW, and 87Sr/86Sr values of the host limestones of the Jiushidaoban Formation range from 3.6‰ to 5.3‰, 18.0‰ to 20.5‰, and 0.707372 to 0.707945, respectively. The δ13CV-PDB and 87Sr/86Sr values of hydrothermal calcite and limestone are similar, indicating single sources of C and Sr in this deposit, with the likely source being the limestone of the Jiushidaoban Formation. The minor scattering of the δ18OV-SMOW values suggests that different O isotope fluids underwent the isotope exchange reaction. The C-O-Sr isotope characteristics indicate that the host limestones experienced a dissolution and precipitation process during mineralization, which is beneficial to improving the porosity of host rocks and promoting the precipitation of metal sulfides. The δ34SV-CDT value of the breccia-type mineralization sulfides ranges from −30.4‰ to −0.3‰; that is, the δ34SV-CDT value is negative with considerable variation, illustrating that during the breccia-type mineralization process, the bacteriogenic reduction of sulfates provided the vast majority of sulfur, whereas the thermochemical reduction of sulfates was relatively unimportant The brecciation that occurred as a result of karst cave collapse was mainly generated by the dissolution of groundwater; however, the brecciation related to hydrothermal dissolution and mineralization processes were caused by mixing of different fluids.

Lead and zinc resources are abundant in China, with the reserves of 100 million tons ranking only second in the world. There are more than 3000 lead-zinc mine areas nationwide. The classification of lead-zinc (Pb-Zn) deposits has been a highly controversial issue. From the standpoint of evaluating the potential of mineral resources, we construct a Pb-Zn deposit predictive type of classification scheme, and propose a Pb-Zn deposit comprehensive classification scheme (including 5 classes and 13 sub-types) that regards mineralization as the primary factor and the ore rock as secondary. According to the temporal and spatial distribution of Pb-Zn deposits, we conclude that a multi-period, multi-cycle orogenic environment is the most favorable for lead-zinc deposit growth, that the Proterozoic is the major eon for the growth of igneous-type deposits, the Paleozoic is an important development era for sedimentary Pb-Zn deposits, and the Mesozoic and Cenozoic are the heyday eras of magmatic type lead-zinc deposits. On this basis, we analyse the relationship between tectonic evolution and Pb-Zn metallogenic, and propose that the key factors determining geological mineralization are the metallogenic epoch of mineralization and tectonic environment, which determine the temporal and spatial distribution.

The Zhaxikang Pb-Zn-Sb polymetallic deposit is one of the most important deposits in the newly recognized southern Tibet antimony-gold metallogenic belt. Compared to the porphyry deposits in the Gangdese belt, much less researches have addressed these deposits, and the genesis of the Zhaxikang deposit is still controversial. Based on field investigation, petrographic, microthermometric, Laser Raman Microprobe (LRM) and SEM/EDS analyses of fluid, melt-fluid, melt and solid inclusions in quartz and beryl from pegmatite, this paper documents the characteristics and the evolution of primary magmatic fluid which was genetically related to greisenization, pegmatitization, and silification in the area. The results show that the primary magmatic fluids were derived from unmixing between melt and fluid and underwent a phase separation process soon after the exsolution. The primary magmatic fluids are of low salinity, high temperature, and can be approximated by the H2O-NaCl-CO2 system. The presence of Mn-Fe carbonate in melt-fluid inclusions and a Zn-bearing mineral (gahnite) trapped in beryl and in inclusions from pegmatite indicates high Mn, Fe, and Zn concentrations in the parent magma and magmatic fluids, and implies a genetic link between pegmatite and Pb-Zn-Sb mineralization. High B and F concentrations in the parent magma largely lower the solidus of the magma and lead to late fluid exsolution, thus the primary magmatic fluids related to pegmatite have much lower temperature than those in most porphyry systems. Boiling of the primary magmatic fluids leads to high-salinity and high-temperature fluids which have high capacity to transport Pb, Zn and Sb. The decrease in temperature and mixing with fluids from other sources may have caused the precipitation of Pb-Zn-Sn (Au) minerals in the distal fault systems surrounding the causative intrusion.

The barium deposits in Ankang and Xunyang counties, Shaanxi Province, China, occur in the northernmost part of the world-class barium metallogenic belt in south Qinling. The deposits are hosted by the Lower Silurian carbonaceous siliceous rocks, with a unique combination of barite and witherite. The homogenization temperatures of fluid inclusions in the barite are mainly concentrated between 135 and 155 °C, whereas those from the witherite have two peaks of 165–175 °C, and 215–225 °C, respectively. Laser Raman analysis of fluid inclusions indicates that the vapor phase of fluid inclusions in barite is dominated by H2O, although some contains N2, H2S, and CH4. The compositions of the vapor and liquid phases of fluid inclusions in witherite can be divided into two end-members, one dominated by H2O without other volatiles, and the other containing CH4, C2H6, C3H8, C2H4, and C6H6 in addition to H2O. CO2, H2S, and some CH4 are interpreted as products of chemical reactions during mineralization. Organic gases (CH4, C2H6, C3H8, C2H4, and C6H6) in the fluids were critical in the formation of barium sulfate versus carbonate. The δ34S values of barite range from 38.26‰ to 54.23‰ (CDT), the δ34S values of sulfides coexisting with barium minerals vary from 22.44‰ to 25.11‰ (CDT), and those in the wall rock from 11.60‰ to 19.06‰ (CDT). We propose that the SO42– generally experienced bacterial sulfate reduction in seawater before mineralization, and some SO42– also experienced thermochemical sulfate reduction in hydrothermal system during mineralization. The δ13C values of witherite range from –27.30‰ to –11.80‰ (PDB), suggesting that carbon was sourced from organic substances (like CH4, C2H4, and C2H6). The formation of witherite was possibly associated with thermochemical sulfate reduction, which caused the consumption of the organic gases and SO42– in the hydrothermal solutions, consequently inhibiting barite formation. The important conditions for forming witherite include high fluid temperatures, high Ba2+ concentrations, CO2 in the fluids, low HS− concentrations, and the subsequent rapid diffusion of H2S during thermochemical sulfate reduction of the fluids.

The Datuanshan deposit is one of the largest and most representative stratabound copper deposits in the Tongling area, the largest ore district in the Middle–Lower Yangtze River metallogenic belt. The location of the orebodies is controlled by the interlayer–slipping faults between the Triassic and Permian strata, and all the orebodies are distributed in stratiform shape around the Mesozoic quartz monzodiorite dikes. Based on field evidence and petrographic observations, four mineralization stages in the Datuanshan deposit have been identified: the skarn, early quartz–sulfide, late quartz–sulfide and carbonate stages. Chalcopytite is the main copper mineral and mainly formed at the late quartz–sulfide stage. Fluid inclusions at different stages were studied for petrography, microthermometry, laser Raman spectrometry and stable isotopes. Four types of fluid inclusions, including three-phase fluid inclusions (type 1), liquid-rich fluid inclusions (type 2), vapour–rich fluid inclusions (type 3) and pure vapour fluid inclusions (type 4), were observed. The minerals from the skarn, early and late quartz–sulfide stages contain all fluid inclusion types, but only type 2 fluid inclusions were observed at the carbonate stage. Petrographic observations suggest that most of the inclusions studied in this paper are likely primary. The coexistence of different types of fluid inclusions with contrasting homogenization characteristics (to the liquid and vapour phase, respectively) and similar homogenization temperatures (the modes are 440–480°C, 380–400°C and 280–320°C for the skarn, early and late quartz–sulfide stages, respectively) in the first three stages, strongly suggests that three episodes of fluid boiling occurred during these stages, which is supported by the hydrogen isotope data. Laser Raman spectra identified CH4 at the skarn and early quartz–sulfide stages. Combined with other geological features, the early ore–forming fluids were inferred to be under a relatively reduced environment. The CO2 component has been identified at the late quartz–sulfide and carbonate stages, indicating that the late ore-forming fluids were under a relatively oxidized environment, probably as a result of inflow of and mixing with meteoric water. In addition, microthermometric results of fluid inclusions and H–O isotope data indicate that the ore forming fluids were dominated by magmatic water in the early stages (skarn and early quartz–sulfide stages) and mixed with meteoric water in the late stages (late quartz–sulfide and carbonate stages). The evidence listed above suggests that the chalcopyrite deposition in the Datuanshan deposit probably resulted from the combination of multi-episode fluid boiling and mixing of magmatic and meteoric water.

The Dahutang tungsten polymetallic ore field is located north of the Nanling W–Sn polymetallic metallogenic belt and south of the Middle–Lower Yangtze River Valley Cu–Mo–Au–Fe porphyry-skarn belt. It is a newly discovered ore field, and probably represents the largest tungsten mineralization district in the world. The Shimensi deposit is one of the mineral deposits in the Dahutang ore field, and is associated with Yanshanian granites intruding into a Neoproterozoic granodiorite batholith. On the basis of geologic studies, this paper presents new petrographic, microthermometric, laser Raman spectroscopic and hydrogen and oxygen isotopic studies of fluid inclusions from the Shimensi deposit. The results show that there are three types of fluid inclusions in quartz from various mineralization stages: liquid-rich two-phase fluid inclusions, vapor-rich two-phase fluid inclusions, and three-phase fluid inclusions containing a solid crystal, with the vast majority being liquid-rich two-phase fluid inclusions. In addition, melt and melt-fluid inclusions were also found in quartz from pegmatoid bodies in the margin of the Yanshanian intrusion. The homogenization temperatures of liquid-rich two-phase fluid inclusions in quartz range from 162 to 363°C and salinities are 0.5wt%–9.5wt% NaCl equivalent. From the early to late mineralization stages, with the decreasing of the homogenization temperature, the salinity also shows a decreasing trend. The ore-forming fluids can be approximated by a NaCl–H2O fluid system, with small amounts of volatile components including CO2, CH4 and N2, as suggested by Laser Raman spectroscopic analyses. The hydrogen and oxygen isotope data show that δDV.SMOW values of bulk fluid inclusions in quartz from various mineralization stages vary from –63.8‰ to –108.4‰, and the δ18OH2O values calculated from the δ18OV-SMOW values of quartz vary from –2.28‰ to –7.21‰. These H–O isotopic data are interpreted to indicate that the ore-forming fluids are mainly composed of magmatic water in the early stage, and meteoric water was added and participated in mineralization in the late stage. Integrating the geological characteristics and analytical data, we propose that the ore-forming fluids of the Shimensi deposit were mainly derived from Yanshanian granitic magma, the evolution of which resulted in highly differentiated melt, as recorded by melt and melt-fluid inclusions in pegmatoid quartz, and high concentrations of metals in the fluids. Cooling of the ore-forming fluids and mixing with meteoric water may be the key factors that led to mineralization in the Dahutang tungsten polymetallic ore field.

The Tongling ore-cluster field, South Anhui Province is an important metallogenic base for Cu-Au-Fe-S mineralization in the Middle-Lower Yangtze Metallogenic Belt. The large Xinqiao Cu-Au-Fe-S deposit, situated the east of Tongling city, is a typically representative in this ore -cluster field. It locates at the intersection of the northern limb of the NNE-trending Shujiadian anticline and the

The Xiangcheng-Luoji area is located in the conjunction of the southern part of the “Sanjiang” mineralization belt and the west margin of Yangtze craton. The geological studies were carried out to know the Indosinian large porphyry Cu polymetallic deposits. Recent studies revealed that the area existed in the superposition of Late Yanshanian acidic intrusive rock belt and developed Mo-Cu polymetallic mineralization where promising exploration results have been achieved. Through the systematic study of geochronology, formation age of the Renlin Mo-minieralization monzogranite is 81.7±1.1 Ma. Re-Os dating results concentrate on 82.34±1.2–88.27±1.23 Ma for the model ages of molbdenite of Tongchanggou Mo deposits, average age is 85 ± 2 Ma where seven data points constitute a good isochron which shows that they were the same period products of mineralization. Geochemical features shown that the rocks have a high content of SiO2 (66.59–77.36wt%), alkaline-rich (K2O=2.68–6.08wt%; Na2O=0.50–4.91wt%; K2O/Na2O ratios are 0.71–5.56, where average ratio of 1.89) and have aluminum-rich features (Al2O310.38–15.15wt%) with σ values less than 3.3. Which indicate that they belong to the high-K calc-alkali to shoshonite series. Geochemistry of Yanshanian intrusions shows that rocks are enrich in LREE with obvious negative δEu anomalies, enrichment of trace elements like, LILE elements (Rb, Th, Ba) with a relative loss of Ba, and loss of high field strength elements (Nb, Ta, P, Ti) and HREE elements. The granite genetic classification diagram shows that the granites belong to A-type granite and formatted in syn-collision tectonic environment. Meanwhile, the Yanshanian granites also inherited the characteristics of island arc environment which formed in the process of crustal melting caused by upwelling of asthenospheric substances in the extensional tectonic background. The process of partial melting existed substances from the deep (lower crust or upper mantle) which have been added. In the Xiangcheng-Luoji area, monzogranite and granodiorite porphyry bodies are widely developed Mo polymetallic mineralization, the deep porphyry mineralization have great potential for geological prospecting.

The carbonaceous-siliceous-argillitic rock type uranium deposit in the Zoige area is located in the northeastern margin of the Tibetan Plateau, and has gained much attention of many geologists and ore deposit experts due to its scale, high grade and abundant associated ores. Because of the insufficient reliable dating of intrusive rocks, the relationship between mineralization and the magmatic activities is still unknown. In order to study this key scientific issue and the ore-forming processes of the Zoige uranium ore field, the LA-ICP-MS zircon U-Pb dating of magmatic rocks was obtained: 64.08±0.59 Ma for the granite-prophyry and ∼200 Ma for the dolerite. U-Pb dating results of uraninite from the Zoige uranium ore field are mainly concentrated on ∼90 Ma and ∼60 Ma. According to LA-ICP-MS U-Pb zircon dating, the ages for the dolerite, porphyry granite and granodiorite are 200 Ma, 64.08 Ma approximately and 226.5–200.88 Ma, respectively. This indicates that the mineralization has close relationship with activities of the intermediate-acidic magma. The ages of the granite porphyry are consistent with those uraninite U-Pb dating results achieved by previous studies, which reflects the magmatic and ore-forming event during the later Yanshanian. Based on the data from previous researches, the ore bodies in the Zoige uranium ore field can be divided into two categories: the single uranium type and the uranium with polymetal mineralization type. The former formed at late Cretaceous (about 90 Ma), while the latter, closely related to the granite porphyry, formed at early Paleogene (about 60 Ma). And apart from ore forming elemental uranium, the latter is often associated with polymetallic elements, such as molybdenum, nickel, zinc, etc.

The northwest of Jiaodong peninsula is characterized by its greatest gold concentration area, enormous gold reserves and limited time interval (115±5Ma) of gold mineralization in China. Studies show that the east area of north China began its mantle plume evolution since the Yanshanian movement, and the Laiyang sub-mantle plume and its surrounding mantle branches such as those in Guojiadian, Aishan and Panshidian were formed in the mineralization concentration area of northwestern Jiaodong peninsula. With the development of mantle plume sub-mantle plume mantle branch favorable expending structures, the deep-derived hydrothermal fluid moved up to the favorable places, such as brittle-ductile or ductile-brittle shearing zones, the internal and external contact zones of intrusions, dense fracturing zones and the contact zones between dikes and countryrocks, and concentrated into deposits. Then the gold mineralization concentration zones that are centralized on mantle branches were formed. This study takes Guojiadian mantle branch as an example to discuss their metallogenetism and conclude the metallogenetic mode.

The Geza island-arc is a well-known mineralization concentration area, part of the Sanjiang Domain at the east margin of the Tibetan Plateau. In recent years, several Late Yanshanian granitic intrusions and associated deposits have been found in this region, the largest one of which in the Shangri-La region is the Laba molybdenum deposit. Previous studies suggested that the timing of the Laba mineralization is 85 ± 2 Ma. However, the ages of the granodioritic porphyry remain unknown. In this study, LA-ICP-MS U-Pb dating of zircons from three samples of the molybdenite-bearing granodioritic porphyry has been conducted with resulting dates of 85.00 ± 0.23 Ma (MSWD = 0.58), 85.28 ± 0.28 Ma (MSWD = 1.12), and 84.83 ± 0.26 Ma (MSWD = 0.79), respectively, indicating that these granodioritic porphyries formed in the Late Yanshanian around ∼85 Ma. Combined with the geological features of the mineralization, the Laba deposit is spatially, temporally, and probably genetically associated with the granodioritic porphyries. In addition, the ages of the Laba deposits are consistent with the other Late Yanshanian intrusions and mineralization, suggesting that the mineralization was probably generated under an intra-plate extensional environment during the Late Cretaceous.

The Yinkeng orefield in Yudu County, Jiangxi Province, SE China, is a zone of concentrated Au-Ag-Pb-Zn-Cu-Mn polymetallic ores. Based on summing up basic geology and ore geology of the orefield, the polymetallic deposits in the orefield have been divided into seven major substyles according to their occurring positions and control factors. The ore-forming fluid inclusion styles in the orefield include those of two-phase fluid, liquid CO2-bearing three-phase and daughter mineral-bearing multi-phase. The homogenization temperatures range from 382° to 122°C, falling into five clusters of 370° to 390°, 300° to 360°, 230° to 300°, 210° to 290° and 120° to 200°, and the clusters of 300° to 360°, 230° to 300° and 120° to 200° are three major mineralization stages, with fluid salinity peaks from 4.14% to 7.31%, 2.07% to 7.31% and 0.53% to 3.90%, respectively. The ore-forming fluids are mainly type of NaCl-H2O with medium to high density (0.74–1.02 g/cm3), or CO2-bearing NaCl-H2O with medium to low density (0.18–0.79 g/cm3). The fluid salinity and density both show a decline tendency with decreasing temperature. According to the measurement and calculation of H- and O-isotopic compositions in the quartz of the quartz-sulfide veins, δDV-SMOW of the ore-forming fluid is from –84‰ to –54‰, and δ18OV-SMOW of that is from 6.75‰ to 9.21‰, indicating a magmatic fluid. The δ34SV-SDT of sulfides in the ores fall into two groups, one is from –4.4‰ to 2.2‰ with average of –1.42‰, and the other from 18.8‰ to 21.6‰ with average of 19.8‰. The S-isotopic data shows one peak at –4.4‰ to 2.2‰ (meaning –1.42‰) suggesting a simple magmatic sulfur source. The ore Pb-isotopic ratios are 206Pb/204Pb from 17.817 to 17.983, 207Pb/204Pb from 15.470 to 15.620 and 208Pb/204Pb from 38.072 to 38.481, indicating characteristics of mantle-derived lead. The data show that the major ore deposits in the orefield have a magmatic-hydrothermal genesis and that the SHRIMP zircon age of the granodiorite porphyry, closely related to the mineralization, is 151.2±4.2 Ma (MSWD = 1.3), which can represent the formation ages of the ores and intrusion rocks. The study aids understanding of the ore-forming processes of the major metallic ore deposits in the orefield.

The recent deep prospecting results in the Jiaojia area of Eastern Shandong Province indicate that the Jiaojia ore field composed of several individual gold deposits as previously suggested is actually an ultra-large gold deposit. This deposit covers an area of ∼40 km2, and shows a structural control by the Jiaojia fault and its secondary faults. Gold orebodies generally occur along the same mineralization-alteration belt, and the main orebodies intersect with each other or exhibit a parallel or overlapping distribution. This deposit's reserves are estimated to be 1, 200t of gold, being the first gold deposit of more than 1000t gold reserves in China. The No. I-1 orebody in the Shaling-deep Sizhuang ore blocks holds gold reserves greater than 350 t, or 29 percent of the total reserves, followed by the No. I orebody in Matang-Jiaojia ore blocks with exceeding 150t gold reserves. This deposit mainly occurs in the footwall of the Jiaojia fault, and presents zoned patterns in mineralization, alteration and structures. The strongly mineralized zones agree with strongly altered and tectonically fractured zones. These orebodies display strataform-like, veinlike or lenticular shapes, and generally show characteristics of pinching out and reappearing, branching and converging, expanding and shrinking. The orebodies commonly occur along positions where the fault strike changes and in gentle locations with dips changing from steep to gentle. The main orebodies are parallel to the main plane of the ore-controlling fault, and tend to be gentle from the surface to the deep. The orebodies mainly plunge to the southwest, with plunge angle of 45°–60°. Orebodies near the main plane of the ore-controlling fault have more gold resource than those away from main fault zone. The slant depth of orebodies is generally larger than the length along its strike direction; orebodies become thick and gold grades become low from the shallow area to the deep area. Ore-forming fluids are H2O-CO2-NaCl±CH4 type with medium-temperature and moderate to low salinity. Sulfur isotopic values (δ34SCDT) for gold ores range between 11.08‰ and 12.58‰, indicating mixed sulfur sources; hydrogen isotopic values (δDV-SMOW) range from –83.68‰ to –116.95‰ and oxygen isotopic values (δ18OV-SMOW) range between 12.04‰ and 16.28‰. The hydrogen and oxygen isotopes suggest that ore-forming fluids originated from primary magma, and mixing with a large amount of atmospheric water during the late stage. The Eastern Shandong Province gold deposits are associated with magmatic activities which have mantle-crust-mixed source, and also share some similarities with orgenic and epithermal hydrothermal gold deposits. Because Eastern Shandong Province gold deposits with unique metallogenic features and formation setting which are different from other gold deposit types in the world, we call it the Jiaojia-type gold deposits. The kiloton class Jiaojia gold deposit is related to fluid activities, extension and detachment resulted from thermal upwelling of magmas. The strong magmatic activities in the middle to late stage of early Cretaceous in Eastern Shandong Province lead to active fluids, and provided abundant ore-forming materials for gold depsoits. Moreover, many extensional structures resulting from crustal extension provided favourable space for orebody positioning.

The Kendekeke polymetallic deposit, located in the middle part of the magmatic arc belt of Qimantag on the southwestern margin of the Qaidam Basin, is a polygenetic compound deposit in the Qimantag metallogenic belt of Qinghai Province. Multi-periodic ore-forming processes occurred in this deposit, including early-stage iron mineralization and lead-zinc-gold-polymetallic mineralization which was controlled by later hydrothermal process. The characteristics of the ore-forming fluids and mineralization were discussed by using the fluid inclusion petrography, Laser Raman Spectrum and micro-thermometry methods. Three stages, namely, S1-stage (copper-iron-sulfide stage), S2-stage (lead-zinc-sulfide stage) and C-stage (carbonate stage) were included in the hydrothermal process as indicated by the results of this study. The fluid inclusions are in three types: aqueous inclusion (type I), CO2-aqueous inclusion (type II) and pure CO2 inclusion (type III). Type I inclusions were observed in the Si-stage, having homogenization temperature at 240–320°C, and salinities ranging from 19.8% to 25.0% (wt% NaCl equiv.). All three types of inclusions, existing as immiscible inclusion assemblages, were presented in the S2-stage, with the lowest homogenization temperature ranging from 175 °C to 295°C, which represents the metallogenic temperature of the S2-stage. The salinities of these inclusions are in the range of 1.5% to 16%. The fluid inclusions in the C-stage belong to types I, II and III, having homogenization temperatures at 120–210°C, and salinities ranging from 0.9% to 14.5%. These observations indicate that the ore-forming fluids evolved from high-temperature to low-temperature, from high-salinity to low-salinity, from homogenization to immiscible separation. Results of Laser Raman Spectroscopy show that high density of CO2 and CH4 were found as gas compositions in the inclusions. CO2, worked as the pH buffer of ore-forming fluids, together with reduction of organic gases (i.e. CH4, etc), affected the transport and sediment of the minerals. The fluid system alternated between open and close systems, namely, between lithostatic pressure and hydrostatic pressure systems. The calculated metallogenic pressures are in the range of 30 to 87 Mpa corresponding to 3 km mineralization depth. Under the influence of tectonic movements, immiscible separation occurred in the original ore-forming fluids, which were derived from the previous high-salinity, high-temperature magmatic fluids. The separation of CO2 changed the physicochemical properties and composition of the original fluids, and then diluted by mixing with extraneous fluids such as meteoric water and groundwater, and metallogenic materials in the fluids such as lead, zinc and gold were precipitated.

The Gol-e-Zard Zn-Pb deposit is one of several sediment-hosted Zn-Pb deposits found in the central part of the Sanadaj-Sirjan Zone, known as the Isfahan-Malayer belt, western Iran. Mineralization occurs in Upper Triassic to Jurassic phyllites and meta-sandstones. Sphalerite and galena are the most abundant metallic ores, with minor chalcopyrite. Calcite and quartz are the main gangue minerals. Fissure filling, replacement textures and especially mineralized faults, suggest an epigenetic stage in the Gol-e-Zard deposit formation. Geochemical studies of mineralized rocks show high concentrations of Zn, Pb and Cu, (Zn and Pb > 10000 ppm and Cu average 3000 ppm). LREE enrichment (LREE>HREE, La/Lu average 1.44) and positive Eu anomalies (Eu/Eu*>1 average 1.67) indicate reducing conditions during the deposition of deposit. However, some samples do not display negative Ce anomalies, which indicate that localized oxidizing conditions are also present. This study indicates that the Gol-e-Zard deposit formed due to circulating hydrothermal fluids in a marine environment. A SEDEX-type genesis, which is defined by circulating hydrothermal fluids through sediments in a marine environment, and syngenetic precipitation of Zn and Pb sulphides, is suggested for the Gol-e-Zard deposit. Emplacement of some granitoid intrusions such as the Aligudarz granitoid intrusion remobilized mineralizing fluids and metamorphosed the Gol-e-Zard deposit.

The SEM-EDX technique was applied to investigate Au, and Cu+Sn alloyed grains in the mineralization of the Um Shashoba mine for achieving further understanding of occurrences, internal structures and microchemistry of Au and Cu alloys and associated minerals, and mineralization type. This study is aiming at the genetic history of ore-bearing fluid events, geochemical evaluation and exploration significance. The results showed that the mineralization could be considered as a single major episode generated by metamorphic mesothermal solution rich in sulfides and unsaturated respect to Au. It was differentiated into many stages; started with formation of auriferous pyrite that was pseudomorphed by secondary hematite, limonite and goethite. Three phases of Au alloy were precipitated, and Cu+Sn and Ag-rich alloys were produced respectively and followed by deposition of two generations of barren pyrite. Calcite and ankerite were crystalized, surrounded and partially replaced some of early formed minerals. Finally, barren muscovite recrystallized around and inside both later formed carbonate minerals that were free of any sign of Au in their structures. The processes of deformation, recrystallization, annealing, dissolution, remobilization and re-precipitation played the most important roles in the genetic history of the mineralization.

Albitite often accompanies with various metal and gem mineral deposits and a large number of occurrences have been reported globally, including the South Qinling orogen, China. The Xiaozhen copper deposit is a typical deposit in the North Daba Mountain area of the South Qinling orogen whose distribution is controlled by albitite veins and fractures. As there are few studies on the petrogenesis of albitite in Xiaozhen copper deposit, this paper focuses on the petrogenesis of albitite and its mineralization age. Detailed fieldwork and mineral microscopic observations initially suggest that albitite from the Xiaozhen copper deposit is igneous in origin. Further zircon trace element geochemistry studies indicate that these zircons have high Th/U ratios (>0.5), low La content, high (Sm/La)N and Ce/Ce* values, and a strong negative Eu anomaly, which are commonly seen in magmatic zircons. The chondrite–normalized rare earth element (REE) patterns are consistent with magmatic zircons from throughout the world, and they fall within or near the field of magmatic zircons on discriminant diagrams. The calculated average apparent Ti–in–zircon temperature for young zircons is 780°C, consistent with magmatic zircon crystallization temperatures. Therefore, zircon geochemistry indicates that the albitite origin is magmatic. SIMS U–Pb dating on nine magmatic zircons yielded a concordia age of 154.8±2.2 Ma, which represents the formation of albitite and the metallogenic age. More importantly, it is consistent with the ages of Yanshanian magmatism and metallogenesis in the South Qinling orogen, so formation of the Xiaozhen copper deposit may be a closely related geological event.

The Jinshan gold deposit is located in the Northeast Jiangxi province, South China, which related to the ductile shear zone. It contains two ore types, i.e. the alteration-type ore and the gold-bearing quartz vein ore. Rb-Sr age dating is applied to both gold-bearing pyrite in the alteration-type ore and fluid inclusion in the gold-bearing quartz vein to make clear the time of the gold mineralization of the Jinshan deposit. Analytical results of this study yielded that the age of the alteration-type ore bodies is about 838±110Ma, with an initial 87Sr/86Sr value of 0.7045±0.0020. However, the age of the gold-bearing quartz vein-type ore is about 379±49Ma, and the initial 87Sr/86Sr is 0.7138±0.0011. Based on the age data from this work and many previous studies, the authors consider that the Jinshan gold deposit is a product of multi-staged mineralization, which may include the Jinninian, Caledonian, Hercynian, and Yanshanian Periods. Among them, the Jinninian Period and the Hercynian Period might be the two most important ore-forming periods for Jinshan deposit. The Jinninian Period is the main stage for the formation of alteration-type ore bodies, while the Hercynian Period is the major time for ore bodies of gold-bearing quartz vein type. The initial values of the 87Sr/86Sr from this study, as well as the previous isotope and trace element studies, indicate that the ore-forming materials mainly derived from the metamorphic wall rocks, and the ore-forming fluids mainly originated from the deep metamorphic water.