Spatial and temporal processes of variations in garnet composition and corresponding fluid evolution during the prograde skarn stage are matters of ongoing controversy. Here, we combine in situ U-Pb geochronology and major- and trace-element compositions of garnet (Grt) in the Muzuke Fe-Cu polymetallic skarn deposit to address the above debate. Three generations of garnets were identified concerning their locations in the contact zone, colors, textural and optical characteristics, and chemical compositions. They belong to the grossularandradite solid solution and are characterized by a temporal and spatial chemistry zonation, which ranges greatly in composition from nearly pure grossular (Grs98Adr0.6) during early prograde stage in endoskarn and proximal exoskarn to almost pure andradite (Grs1.7Adr97) during late prograde stage in distal exoskarn. We observed a clear correspondence between the major-element compositions and optical characteristics of garnet from Muzuke, and the formation of the birefringent garnets is probably induced by the symmetry reduction due to trivalent cation ordering varieties at the Y site in the regular octahedron. From Grt-1 to Grt-3, the overall REE patterns shift from HREE enrichment to LREE enrichment, accompanied by negative to positive Eu anomalies, which can be attributed to the relative proportion of grossular and andradite end-members, while the chemical composition of fluid in the late prograde stage also has some effects on the REE patterns of garnet. The transitions of geochemical characteristics between three generations of garnets suggest that despite the existence of multiple pulses of fluid flux in the prograde stage, the overall trend of fluids evolution indicates that from the early to terminal prograde stage, from endoskarn to distal exoskarn, the formation mechanism of skarn transitions from diffusion metasomatism under a closed system to advective metasomatism under an open system, accompanied by a gradual decrease in temperature of hydrothermal fluids and an increase in fO2 and W/R ratios. The above process inhibited premature sulfide precipitation and may be a precursor to the precipitation of magnetite in the later stage. In situ U-Pb dating on garnet yields an age of 364.9 +/- 7.6 Ma for Grt-2 and of 363.2 +/- 4.5 Ma to 363.0 +/- 2.0 Ma for Grt-3 from the Muzuke deposit, suggesting a genetic connection between the polymetallic mineralization and the emplacement of the nearby granodioritic intrusion. The garnet spatial-temporal evolution model established in this study could assist in localizing and exploring regional skarn ore bodies with similar causative intrusions and wall rock properties.

The Jinchanggouliang gold deposit, containing exceeding 40 tons Au, is a quintessential large-scale deposit formed during the Yanshanian mineralization period in the northern margin of the North China Craton. However, previous studies have been highly controversial regarding the properties and evolution of ore-forming fluids, as well as the ore-forming conditions. This study employs H-O isotope analysis, fluid inclusion petrographic observation and microthermometry, in-situ LA-ICP-MS analysis of quartz and individual fluid inclusions to constrain the origin and properties of the ore-forming fluid, the fluid evolution process, and the Au precipitation mechanism. The mineralization process at Jinchanggouliang is divided into three stages: milky quartz (Q1, stage I), quartz (Q2) + pyrite (stage II), quartz (Q3) + polymetallic sulfides (stage III). Stage III represents the principal mineralizing phase within the paragenetic sequence of the hydrothermal system. The primary fluid inclusion types are divided into three categories: two-phase aqueous inclusions (type I), two-phase CO2-bearing aqueous inclusions (type II), and three-phase solid-bearing inclusions (type III). Microthermometry results indicate that the homogenization temperature progressively decreases from stage I to stage III, with significant salinity fluctuations. The ore-forming fluid is categorized within the H2O-NaCl system, displaying features indicative of high-temperature conditions and a variable salinity range (1.7-37.8 wt% NaCl equiv.). Fluid boiling occurs at stage III. In-situ LA-ICP-MS analysis of fluid inclusions, combined with stable H-O isotope studies of quartz, delineates that the fluid is primarily sourced from magmatic water, with a contribution of meteoric water during the main metallogenic stage. The Rb/Cs ratio of fluid inclusions remains relatively stable across all stages, with values oscillating within a narrow range of 1-10, indicating a single source for the fluid system. As the progression from the stage I to III, the Ti content in quartz gradually decreases, while the Al and Sb contents increase. The correlation between Al and Li, as well as between Al and the sum of Li, Na and K, gradually increases, indicating a transition from single substitution to compensated substitution in quartz from the pre-ore to the main-ore stage. The formation conditions of quartz in each stage, calculated using TitaniQ, and fluid inclusion P-T formulas, are approximately 1.43 kbar at 548 degrees C for stage I, 0.73 kbar at 441 degrees C for stage II, and 0.14 kbar at 341 degrees C for stage III. As the fluid progressed towards the main mineralization stage, the lithostatic pressure transitioned to hydrostatic pressure. Fluid boiling in stage III is attributed to rapid pressure reduction. The escape of acidic volatiles and the addition of meteoric water gradually increase the pH. These physicochemical perturbations triggered extensive metal precipitation and mineralization, including Au. According to the experimental data and ore body occurrence, Jinchanggouliang gold deposit should be classified as the magmatichydrothermal vein type, which have a certain prospecting potential for porphyry and epithermal mineralization.

The northern margin of the North China Craton experienced prolonged tectono-magmatic evolution during the late Paleozoic- early Mesozoic in response to the southward subduction and closure of the Paleo-Asian Ocean. However, details about the subduction process and the timing of the tectonic transition from subduction to post-collision are still poorly constrained. Here, we identify two-stage crust-mantle interactions in the Wulashan area and report new geochronology, geochemistry, and Sr-Nd-Pb-Hf isotopic data for magmatic rocks that record such processes following the subduction and closure of the Paleo-Asian Ocean. The early Carboniferous Xiguanjing pluton features a bimodal suite of gabbro (ca. 333 Ma) and syenogranite (ca. 331 Ma). The gabbros have arc-like geochemical affinities, with low Nb/ La (0.31-0.40) and La/Ba (0.04-0.09) ratios, and variable Rb/Y (1.22-2.94) ratios, as well as enriched, mantle-like Sr-Nd-Pb ( 87 Sr/ 86 Sr i = 0.7046-0.7047; e Nd ( t ) = - 3.8 to - 3.5; 206 Pb/ 204 Pb i = 17.078-17.141) and enriched to depleted Hf ( e Hf ( t ) = - 4.5 to + 6.2) isotopic values. Such geochemical signatures indicate that they were derived from partial melting of the subcontinental lithospheric mantle that was metasomatized by slabderived fluids, with minor involvement of asthenospheric components. In contrast, the contemporaneous syenogranites are characterized by lower negative e Nd ( t ) ( - 13.5 to - 12.1) and e Hf ( t ) values ( - 16.3 to - 8.2), which suggests that they were formed by partial melting of the lower crust. Late Triassic Shadegai and Xishadegai plutons are mainly composed of enclave-bearing syenogranite, and both mafic microgranular enclaves and syenogranites crystallized at ca. 233-231 Ma. The mafic microgranular enclaves have geochemical features similar to those of the early Carboniferous gabbros, and also have moderately enriched isotopic compositions ( e Nd ( t ) = - 9.7 to - 8.4; e Hf ( t ) = - 9.2 to - 0.3), which suggests that they originated from interaction between mantle-derived magma and overlying crust-derived magma, with minor additions of asthenospheric melts in their sources. Field and petrological observations, coupled with the similar ages of the host granites and mafic microgranular enclaves, suggest a magmatic mingling process. Isotopic mixing models suggest that minor amounts ( similar to 10%-20%) of lower crustal materials were mixed during the formation of the mafic microgranular enclaves. The host syenogranites display calc-alkaline to alkalic and metaluminous to weakly peraluminous compositions, and negative e Nd ( t ) ( - 15.0 to - 12.1) and e Hf ( t ) values ( - 16.4 to - 9.8), which indicates that they were mainly derived from partial melting of the lower crust and experienced the injection of deep mantle-derived magmas. Our new data, along with previously published data for magmatic rocks in the northern margin of the North China Craton, suggest that the early Carboniferous bimodal intrusive rocks formed in a localized back-arc extensional regime that was probably triggered by slab rollback of the Paleo-Asian Ocean. However, the Late Triassic plutons formed in a postcollisional extensional regime in response to slab breakoff or lithospheric delamination. Temporal variations of Nd-Hf isotopes for the magmatism in the northern margin of the North China Craton suggest that tectonic switching from advancing to retreating subduction to post-collisional extension occurred during the late Paleozoic to early Mesozoic. We propose that a tectonic transition from subduction to post-collisional extension may have occurred during the Early-Middle Triassic, marking the final closure of the PaleoAsian Ocean, which most likely took place at ca. 250-235 Ma.

The Haerdaban Pb-Zn deposit (with an ore reserve of 10.93 Mt. at 1.0-25.65 % Zn and 0.7-12.29 % Pb) is hosted in weakly metamorphosed clastic-carbonate rocks from the Proterozoic Haerdaban Group. It represents a significant addition of the sediment-hosted Pb-Zn deposits in the Yili block, Chinese western Tianshan. Currently, there are ongoing debates regarding its genesis, with a particular focus on the crucial metallogenic mechanism (syngenetic sedimentary exhalation or epigenetic reworking) responsible for the primary sulfide mineralization. Mineralization at Haerdaban primarily occurs as banded to stratiform ore layers or lenses conformably sandwiched in their host rocks. Vein and stockwork ores occur locally below the stratiform ore layers. A syn-sedimentary fault trending S-N was identified based on abrupt lateral changes in lithofacies and thickness of the stratigraphic units. The ore mineralogy is dominated by sphalerite, galena, quartz, and dolomite, with a small amount of pyrite, barite, and organic matter. Detrital zircon LA-ICP-MS U-Pb dating of the Haerdaban siltstones obtained a maximum depositional age of about 604 Ma. Their geochemical composition similar to the passive continental margin signatures, with rare earth element (REE) patterns enriched in LREE and negative Eu anomalies (Eu/Eu* = 0.50-1.14). Stratiform beds of chert that host disseminated ores have relatively high contents of hydrothermal components (e.g., Ba, Zn), with apparent positive Eu anomalies (Eu/ Eu* = 7.38-49.34) and negligible negative Ce anomalies (Ce/Ce* = 0.85-0.98). They are thus interpreted to be hydrothermal sedimentary rocks (exhalites) deposited in a suboxic-anoxic environment proximal to the hydrothermal vents. Integrated geological and geochemical evidence indicates that the Haerdaban Pb-Zn deposit is a typical vent-proximal sedimentary exhalative (SEDEX) deposit formed in a Neoproterozoic Sinian (Ediacaran) passive continental margin rift basin. Post-depositional metamorphism and deformation in the Paleozoic may have caused partial remobilization of primary ores but did not significantly alter the morphology of the orebodies. Furthermore, establishing a genetic model for the Haerdaban deposit has important implications for the exploration of similar deposits preserved in the equivalent stratigraphy within the Chinese western Tianshan region.

The Tabei Pb–Zn deposit is located adjacent to the well‐known Axi low‐sulphidation epithermal Au deposit in the Tulasu Basin, Chinese Western Tianshan. The homogenization temperatures and salinities of H 2 O‐rich biphase inclusions in ore‐stage sphalerite and calcite from Tabei range from 100 to 170°C and 0.4 to 6.2 wt% NaCleq, respectively. The δ 13 C V‐PDB and δ 18 O V‐SMOW values of calcite range from 0.9‰ to 1.5‰ and 5.6‰ to 6.7‰, respectively. The δ 18 O H2O and δD H2O values of hydrothermal fluids vary from −7.0‰ to −5.9‰ and −120.8‰ to −111.1‰, respectively. The in‐situ δ 34 S V‐CDT values of sulphides range from 7.5‰ to 8.0‰ (average 7.7‰). The in‐situ Pb isotopic compositions of galena and ( 87 Sr/ 86 Sr) 0 ratios of sphalerite resemble those of Au‐bearing pyrite and quartz of Axi deposit, respectively, as well as the ore‐hosting volcanic rocks. These isotopic compositions indicate that the ore metals were derived from the ore‐hosting volcanic rocks, with the ore‐forming fluids consisting predominantly of circulating meteoric water. The absence of coexisting two‐phase vapour and liquid fluid inclusions and the presence of abundant banded coarse‐grained quartz crystals with dog tooth and comb textures at Tabei, suggest that the sulphides precipitated slowly due to conductive cooling. The high sulphide abundance, sulphide assemblage (pyrite + Fe‐poor sphalerite + galena + chalcopyrite), ore textures and isotopic compositions suggest that Tabei represents an intermediate‐sulphidation epithermal deposit. The Axi‐Tabei Au–Pb–Zn epithermal system constitutes a hybrid consisting of Au veins at shallow level and Pb–Zn veins at depth, suggesting that the base metals remain highly prospective beneath the identified Au orebodies at Axi.

The Late Paleozoic Dahuabei Pluton is located in the Wulashan area at the northern margin of the North China Craton (NCC), adjacent to the Hadamengou gold deposit, the largest gold deposit in Inner Mongolia, China. However, its petrogenesis and its relationship with Au-Mo mineralization remain debatable. In this contribu-tion, a geochemical, isotopic, and geochronological study was carried out on the Dahuabei pluton to constrain its magma sources, petrogenesis, and tectonic setting, and further discuss the linkage between the magmatism and Au-Mo mineralization. The Dahuabei pluton mainly consists of monzogranite and syenogranite, with abundant mafic microgranular enclaves (MMEs) in the monzogranite. Zircon U-Pb dating shows that the ages of the Dahuabei pluton range from 357 to 353 Ma, suggesting an Early Carboniferous emplacement. The crystallization age of the MMEs (355.4 +/- 3.2 Ma) is nearly simultaneous to that of host monzogranite (356.5 +/- 2.0 Ma). Geochemically, the granitoids show high-K calc-alkaline and weakly peraluminous affinities and are classified as highly to moderately fractionated I-type granites. Moreover, they are enriched in light rare earth elements and large ion lithophile elements, depleted in high field strength elements, resembling typical continental arc magmatic rocks. Isotopically, the granitoids have negative eNd(t) (-10.0 to-7.3) and eHf(t) values (-10.0 to-4.4), as well as old Nd (1923-1704 Ma) and Hf (1986-1697 Ma) model ages, suggest that the granitoids were mainly derived from partial melting of ancient mafic lower continental crust, with involvement of mantle-derived components. The sharp contacts, fine-grained igneous textures, numerous xenocrysts from host gran-ites, and similar crystallization ages with host granites of the MMEs suggest a magma mingling process, in which the MMEs represent discrete mafic to hybrid magma globules formed by undercooling after the injection of hotter mafic magma into cooler felsic magma. Geochemical and isotopic data (eNd(t) of-6.2 to-5.4 and eHf(t) of-10.2 to-2.8) indicate that the parental magma of MMEs was derived from partial melting of the enriched subcon-tinental lithospheric mantle metasomatized by slab-derived fluids and had experienced significant fractional crystallization. The indistinctive chemical and isotopic contrast between MMEs and host monzogranite implies their chemical and isotopic exchange during various degrees of magma mingling. Integrating the geochrono-logical, geochemical, and Pb isotope data of the Hadamengou Au-Mo deposit and the Dahuebei pluton, we propose that the magmatic-hydrothermal system emanated from the magma mingling event during the emplacement of the Dahuabei pluton might be favorable for the mineralization. The Late Devonian to Early Carboniferous magmatism may have been a trigger for the formation of the Au-Mo deposits in the northern margin of the NCC.

Integrated study on cathodoluminescence (CL) textures and compositions of quartz is proven to be an effective way to reconstruct the ore-forming conditions and processes of porphyry system under subduction tectonic setting. However, little relevant research has been conducted on collision-type porphyry deposits. The Gao-gangshan deposit in the northern Lesser Xing'an Range, NE China, consists of typical collision-type porphyry Mo mineralization related to Permo-Triassic granitic intrusions. Ore-forming process is recorded by multiple gen-erations of quartz, including pre-ore stage quartz with unidirectional solidification texture (UST), early ore-stage quartz-molybdenite veins with K-feldspar alteration halos (Q1), late ore-stage quartz-sulfides veins with sericite alteration (Q2), and post-ore stage quartz veins (Q3) associated with calcite and fluorite. Cathodoluminescent textures, trace elements and fluid inclusions in quartz reveal physicochemical conditions, evolution of ore fluids and the Mo mineralization process. The UST quartz and Q1 veins are dominated by CL-bright homogenous and/ or granular mosaic textures, containing more Ti concentrations (average = 35-42 ppm) than Q2 and Q3 veins. The molybdenite-bearing Q2 veins are dominated by CL-gray granular and zonal textures, displaying less CL intensity and lower Ti concentrations (average = 16 ppm) than early-stage quartz. The Q3 veins have the lowest CL-intensity and the lowest Ti concentrations (average = 2.5 ppm) among all quartz types. Three types of in-clusions are identified in above quartz samples, including liquid-vapor aqueous inclusions, CO2-bearing liq-uid-vapor aqueous inclusions and halite-bearing multiphase aqueous inclusions. The ore-forming fluids in ore-stage Q1 and Q2 veins are dominated by large salinity variation (2.3-38.9 wt% NaCl equiv.), CO2-bearing (4.2-8.9 mol%) two-phase aqueous inclusions with vapor volumetric proportions of 30-65%. Intersections of fluid inclusion isochores with Ti-in-quartz isopleths yield quartz formation conditions of-2.2 kbar at-640 degrees C for UST quartz,-1.25 kbar at-510 degrees C for Q1,-1.0 kbar at-440 degrees C for Q2, and-0.37 kbar at-220 degrees C for Q3. The Gaogangshan porphyry Mo deposit formed at depths of 3.8 to 4.7 km.

The Shijia gold deposit is situated in the north of the Penglai–Qixia gold belt in the Jiaodong Peninsula. Different types of early Cretaceous mafic–felsic dykes, mainly including lamprophyre, diabase, and granite porphyry dykes, are closed associated with gold mineralization in space at Shijia. Based on the study of geochemical characteristics of vein rocks, it is concluded that lamprophyre and diabase dykes are characterized by low contents of SiO2, TFe2O3 and high MgO, they are enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs; Such as Ba, Sr, and Pb), but depleted in high field strength elements (HFSEs; Such as Nb, Ta, Zr, Hf, and Ti). It is considered that lamprophyre and diabase dykes with arc–like trace element patterns are originated from partial melting of the enriched lithospheric mantle. Granite porphyry dykes are peraluminous, high potassium calc–alkaline rocks which are characterized by high concentrations of SiO2, K2O and Al2O3, with enrichment in LREEs and LILEs (Th, U, Rb, Ba, and Pb) and depletion in HFSEs (Ta, Nb, Ti, Zr, and Hf). They were formed by partial melting of greywacks under the background of asthenosphere upwelling and mantle–derived magma underplating. Although some researchers suggest that these dykes can be used as effective ore prospecting indicators, chronological studies show that there is no direct genetic relationship between the dykes and gold mineralization.

The factors controlling the organic matter accumulation in the organic-rich shale of the Lucaogou Formation in the southern Junggar Basin, remain controversial. To more explicitly reveal the hydrothermal events and its mechanism on the organic matter enrichment, we performed mineralogy and geochemistry methods on dolomite and black shale samples from Well FK-1 in Fukang Sag. The high (Fe + Mn)/Ti ratios, the enrichment of Ca, Mg, Fe, Mn, and REY, and multiple hydrothermal minerals (e.g., ankerite, dolomite, zeolite, authigenic albite, and microcline) suggest five episodes of hydrothermal events. In addition, the low-to-high-varied Sr/Ba, V/(V + Ni) (Al + Fe)/(Ca + Mg), and Sr/Cu ratios, as well as the dolomite formation all well indicate a brackish-saline, suboxic-anoxic, shallow to deep water condition under a warm-humid to hot-arid climate with rhythmic sedimentation. The fluctuated total organic carbon content (up to 12.16 wt%) suggest the periodic organic matter accumulation. Three patterns of organic matter enrichment occurred during the rift-drift transition of the southern Junggar Basin, productivity and preservation played distinguishing roles in different intervals. Productivity periodically fluctuated because of the episodic hydrothermal events and warm-humid climate changes. Preservation was triggered by the saline, anoxic, and well-stratified water setting under the relatively hot-arid climate, which became progressively favorable in the gradually stabilized basin.

The Yili Block in the Western Tianshan orogen is a key area for understanding the early crustal formation and evolution of the Central Asian orogenic belt, due to the widely‐distributed Precambrian rocks. Also, it hosts a lot of medium– to large‐scale sedimentary exhalative (SEDEX) Pb‐Zn deposits that mainly occur in Proterozoic metamorphosed clastic‐carbonate rocks. In this study, LA‐ICP‐MS U‐Pb analyses were carried out on detrital zircons in siltstones of the Precambrian Haerdaban Group in the Haerdaban Pb‐Zn deposit and magmatic zircons in the diorite dyke that cuts through the strata and orebodies. The maximum depositional age of the siltstones was determined to be about 604 Ma, the diorite having formed at approximately 500 Ma. As such, the Haerdaban Group was most likely formed in the Neoproterozoic Sinian, rather than the previously considered Mesoproterozoic Changchengian. Detrital materials of the Haerdaban Group were mostly derived from the Nanhua–Sinian mafic dykes and granitic rocks around Lake Sayram at the northern margin of the Yili Block. It is proposed that the Yili Block, together with the Kazakhstan and Central Tianshan blocks and the Tarim Craton, might all pertain to the same Rodinia supercontinent, which has great potential for targeting large to super‐large SEDEX Pb‐Zn deposits.

The depositional age, sedimentary environment and tectonic setting of the Permian Lucaogou Formation in eastern Tianshan Mountains are controversial. Based on the standard fossil assemblages of Turfania taoshuyuanensis and Tomiella found in the Lucaogou Formation, the large number of detrital zircons from the sedimentary strata with the youngest peak age of 261 Ma, it is believed that the deposition age of the Lucaogou Formation is Guadalupan（Middle Permian） rather than Uralian（Early Permian）. Based on the discovery of typical marine indicator mineral glauconite, the discovery of marine facies or the interactional facies of Tomiella and the confirmation of ultra-high salinity saline lake basin, it is considered that the Lucaogou Formation was mainly lacustrine sediments, but some sedimentary periods were affected by transgression（flooding）events. In eastern Tianshan Mountains, the Permian Lucaogou Formaition of Junggar Basin, Santanghu Basin and Tu-Ha Basins has similar rock assemblages, faunal features and tectonic characteristics, but there are differences in paleo-salinity, paleo-water depth, paleo-climate, paleo-redox conditions and primary productivity among different basins, suggesting that the Lucaogou Formation was deposited in a series of dispersed rift basins, and there is no unified depositional center among different basins.

•The Kuokuqueke Fe-Cu skarn deposit comprises four stages of mineralization.•The ore-forming components were mainly derived from granitic magmas.•Two stages of fluid boiling occurred in the whole mineralization process.

Understanding the interrelationship between diagenesis and hydrocarbon emplacement is crucially important for investigating tight sandstone reservoir‐forming processes. In this paper, efforts were made to elucidate this interrelationship in the Jurassic Badaowan Formation tight sandstone reservoirs of the southern margin of the Junggar Basin (SJB), China. Four lithofacies were clarified, including quartz cemented‐dissolution facies (QCDF), carbonate cemented facies (CCF), authigenic clay mineral facies (ACMF), and matrix‐caused tightly compacted facies (MCTF). Weak hydrocarbon migration forces and poor hydrocarbon preservation conditions were identified to be the main reasons for the limited hydrocarbon accumulation scale. The reservoir densification process, mostly before 100 Ma, was associated with four aspects, including the high matrix content, the intensive carbonate cementation, the limited dissolution and alteration, and the development of authigenic clay minerals. Hydrocarbons in the Badaowan Formation reservoir were demonstrated to be emplaced after reservoir densification. Overpressure resulting from hydrocarbon expulsion and tectonic compression should have acted as the main driver for hydrocarbon migration. Particularly, the tight sandstone in the Qigu anticline was charged with overpressurized hydrocarbons sourced from the middle‐lower Jurassic source rocks at the footwall of the Qigu north fault since the early Jurassic. The tectonic compression in the late Neogene eroded the core of the Qigu anticline, which destroyed the initially large palaeo‐oil reservoir into smaller ones. The first‐stage hydrocarbon emplacement greatly affected the diagenesis and physical properties of the reservoir. It played an important role in inhibiting cementation, promoting dissolution, and altering the petrophysical properties of the tight sandstone reservoir. The densification process controlled the wettability and capillary pressure of pores in the tight sandstone. Specifically, the high kaolinite cement raised the hydrophilia, while the ubiquitous densification increased the capillary pressure of pores.

为预测和评价山东蓬莱石家金矿床的深部找矿远景,延长矿山服务年限,着重论述了该矿床的原生晕地球化学特征,对矿床的深部找矿潜力进行了探讨.原生晕元素组合特征分析表明,石家金矿床的矿体及近矿晕元素组合为Au、Ag、Cu、Pb、Zn、S、Te,前缘晕为Hg、As、Sb、Ba,尾晕为Mo、W、Sn.元素异常形态特征显示,326号矿脉南段以前缘晕和近矿晕为主,北段以前缘晕和尾晕为主,近矿晕元素异常较弱,矿体总体具有向南侧伏的特点.原生晕轴向分带序列在36线和84线均呈现反分带和前缘晕、尾晕共存的特点,结合地球化学参数在垂向上呈振荡波动变化的特征,说明矿体由多期次成矿作用叠加形成,同时预示矿体向深部还有一定延伸或有盲矿体存在.综合分析认为,326号矿脉南段为成矿的有利部位,深部仍有较大的找矿空间;矿体北段深部矿化减弱,但出现了前缘晕、尾晕元素的共存,预示深部可能还有盲矿体存在.

The Kuruer Cu-Au deposit is located in the Wusun Range of Yili Block, Chinese Western Tianshan, where numerous epithermal Au, skarn Fe-Cu and porphyry Mo-Cu deposits have been recognized. Petrography, fluid inclusions, S-Pb-H-O isotopes, field emission-scanning electron microscopy (FE-SEM) plus energy dispersive spectrometer (EDS) and electron microprobe analysis (EMPA) have been carried out to constrain the genesis of the Kuruer deposit and its implication for further exploration. The minerlization is hosted by volcanic rocks and occur as veins and veinlets structurally controlled by NW-trending faults. Three ore-forming stages were recognized, including quartz-sulfides-bismuth-gold stage (I), quartz-chalcopyrite stage (II) and calcite-chloritechalcopyrite stage (III). Six types of fluid inclusions were identified in stage I quartz, including monophase vapor inclusions (type 1), liquid-rich biphase inclusions (type 2), vapor-rich biphase inclusions (type 3), H2O-rich CO2-H2O triphase inclusions (type 4), CO2-rich CO2-H2O triphase inclusions (type 5) and solid halite-bearing triphase inclusions (type 6), whereas only type 2 inclusions were recognized in stage II quartz and stage III calcite. Types 2, 3, 4 and 6 inclusions in stage I have homogenization temperature (T-h) ranges of 184-359 degrees C, 209-252 degrees C, 250-319 degrees C and 229-263 degrees C, with salinity ranges of 4.1-8.5 wt% NaCleq, 5.9-6.9 wt% NaCleq, 1.0-6.0 wt% NaCleq and 32.7-33.9 wt% NaCleq, respectively. Type 2 inclusions in stages II and III have Th varying from 144 to 212 degrees C and 114 to 163 degrees C, with salinities of 0.2-6.7 wt% NaCleq and 0.1-3.1 wt% NaCleq, respectively. The in-situ delta S-34 values of sulfides in stage I range from -4.66 to 0.34 parts per thousand. The Pb-206/Pb-204, Pb-207/Pb-204, and Pb-208/Pb-204 ratios of stage I chalcopyrite vary from 18.295 to 18.954, 15.568 to 15.673 and 38.109 to 38.817, respectively, which are consistent with those of Early Carboniferous Dahalajunshan Formation volcanic rocks and granitoids from the Wusun Range. The values of delta(OH2O)-O-18-VSMOW calculated from delta(18)Oquartz and delta DH2O-VSMOW of stage I quartz range from 0.0 to 2.4 parts per thousand and -118.6 to-109.3 parts per thousand, respectively. These isotopic compositions indicate that both metals and sulfur were sourced from the hosting volcanic rocks and hidden causative pluton, while the initial ore-forming fluids were magmatic in origin, with increasing involvement of meteoric water with time. Evidence from mineralogy, mineral geochemistry and fluid inclusions indicates that the initial fluid phase separation triggered the precipitation of "invisible" gold within pyrite and chalcopyrite during stage I. Subsequently, the decrease of f(S2) due to the escape of H2S(g) and sulfide precipitation and cooling caused the formation of liquid bismuth from solutions. The bismuth melts have scavenged Au in situ from the residual solutions, resulting in the formation of Bi-Au inclusions within the fractures and intergranular spaces of earlier pyrite. For stages II and III, dilution and cooling due to input of meteoric water facilitated the chalcopyrite precipitation. The Kuruer Cu-Au deposit is classified as a subepithermal mineralization associated with porphyries. Porphyry Cu-Au mineralization could have developed beneath the Kuruer and its vicinity.

Due to the unknown Triassic volcanism in the Junggar Basin, the Middle-Late Triassic sedimentary provenance in the southern Junggar Basin (SJB) has long been controversial. Detrital zircon grains from 13 samples of the Middle-Upper Triassic Xiaoquangou Group in the SJB were analyzed using zircon U-Pb geochronology to constrain the provenance of Triassic sedimentary rocks and to further understand their source-to-sink system. Comparison of detrital zircon U-Pb age distributions for 13 samples reveals that the Triassic age populations predominate in sediments of the northern Bogda Mountains, with subordinate in the southern Bogda Mountains, and no or minimal in the North Tianshan (NTS). Coupled with sandstone petrological, sedimentary geochemical and paleocurrent data, the Triassic detrital zircon grains of the Xiaoquangou Group in the SJB were probably input from the Bogda Mountains. As Pennsylvanian and Mississippian zircon grains are mainly derived from the NTS and Central Tianshan (CTS), the provenance of the Xiaoquangou Group includes the NTS, CTS and Bogda Mountains. But the different samples in different sink areas have different provenances, originating from at least four source-to-sink systems. The supply of sediments from the Bogda Mountains started in the Late Triassic, suggesting initial uplift of the Bogda Mountains.

Deeply buried sandstones in the Jurassic, Toutunhe Formation, are a crucial exploration target in the Junggar Basin, NW China, whereas, reservoir-forming process of sandstones in the Toutunhe Formation remain unknown. Focused on the tight sandstone of the Toutunhe Formation, the impacts of diagenesis and hydrocarbon charging on sandstone reservoir-forming process were clarified based on the comprehensive analysis of sedimentary characteristics, petrography, petrophysical characteristics, and fluid inclusion analysis. Three diagenetic facies developed in the Toutunhe sandstone reservoirs, including carbonate cemented facies (CCF), matrix-caused tightly compacted facies (MTCF), and weakly diagenetic reformed facies (WDF). Except the WDF, the CCF and the MTCF entered the tight state in 18 Ma and 9 Ma, respectively. There was only one hydrocarbon emplacing event in sandstone reservoir of the Toutunhe Formation, charging in 13 Ma to 8 Ma. Meanwhile, the source rock started to expel hydrocarbons and buoyancy drove the hydrocarbon via the Aika fault belt to migrate into sandstone reservoirs in the Toutunhe Formation. During the end of the Neogene, the paleo-oil reservoir in the Toutunhe Formation was destructed and hydrocarbons migrated to the sandstone reservoirs in the Ziniquanzi Formation; some paleo-oil reservoirs survived in the WDF. The burial pattern and change of reservoir wettability were major controlling factors of the sandstone reservoir-forming process. The buried pattern of the Toutunhe Formation in the western section of the southern Junggar Basin was “slow and shallow burial at early stage and rapid and deep burial at late stage”. Hence, pore capillary pressure was extremely low due to limited diagenetic reformation (average pore capillary pressures were 0.26 MPa). At the same time, high content of chlorite coating increased the lipophilicity of reservoirs. Therefore, hydrocarbons preferably charged into the WDF with low matrix content (average 4.09%), high content of detrital quartz (average 28.75%), high content of chlorite films (average 2.2%), and lower pore capillary pressures (average 0.03 MPa). The above conditions were favorable for oil and gas enrichment.

Provenance analysis for volcanism without field evidence remains a major challenge. Detrital zircon grains from 13 samples of the Middle–Upper Triassic Xiaoquangou Group in the Southern Junggar Basin (SJB) were analyzed using U–Pb geochronology to constrain the location and characteristics of Triassic volcanism in the area as well as to understand its tectonic implications. A comparison of the distribution of detrital zircon U–Pb ages reveals Triassic zircon ages predominate in northern Bogda Mountains, with subordinate contributions also in southern Bogda Mountains, and no or minimal input in North Tianshan piedmont. The geochronology data combined with the euhedral and angular zircon grains suggest that the Triassic zircons probably originate from Bogda Mountains. A comparative provenance analysis reveals varied sources for Xiaoquangou Group in the SJB, with sediments of the Bogda Mountains area derived mainly from North Tianshan, Central Tianshan, and Bogda Mountains. The supply of sediments from Bogda Mountains started in the Late Triassic, and is indicative of the initial uplift of Bogda Mountains. This study proves the effectiveness of the comparison of detrital zircon U–Pb age distributions for inferring source characteristics and is applicable in similar situations, particularly when the source area is poorly preserved.

In this paper, we present new petrological, zircon U-Pb-Hf isotopic, bulk-rock geochemical, and Sr-Nd isotopic data for the rocks from the Pennsylvanian Liushugou and Qijiagou Formations, Bogda Mountains (BMs), northwest China. The new data help in understanding the petrogenesis and geodynamic background of the two formations, further constraining the evolution of BMs during the Pennsylvanian. The eastern Liushugou Formation is composed mainly of bimodal volcanic rocks, while the western Liushugou Formation is dominated by pillow basalts with interstitial limestones, peperites, and pyroclastic rocks. The Qijiagou Formation consists principally of bioclastic limestones, peperites, and volcanic and volcaniclastic rocks with turbidites. Depositional environment analyses of the Liushugou and Qijiagou Formations reveal subaqueous volcanism and a progressively deepening shallow marine environment with times. Zircon LA-ICP-MS U-Pb dating of felsic volcanic rocks from the Liushugou Formation indicates that the subaqueous volcanism occurred at ca. 310-302 Ma, viz., the Pennsylvanian era. The basaltic rocks from the Liushugou and Qijiagou Formations are high-K calc-alkaline, enriched in light rare earth elements and large-ion lithophile elements, and depleted in high-field-strength elements (Nb, Ta, and Ti). The above characteristics, together with their depleted isotopic signature (epsilon(Nd)(t) = 3.0-8.1, epsilon(Hf)(t) = 8.0-15.6, and I-Sr = 0.703-0.707), suggest the derivation from a depleted mantle source metasomatized by slab-derived fluids and sediment-derived melts. Most felsic volcanic rocks of the high-K calc-alkaline to shoshonite series from the Liushugou and Qijiagou Formations show features of the A2-type granites and have similar trace and isotopic composition to the basaltic rocks, which were probably generated from the partial melting of juvenile continental crust. Combining the newly acquired data with the regional geology, we propose that the Pennsylvanian volcanic and sedimentary rocks in the BMs were formed in a series of postcollisional rift basins which were related to local strike-slip faulting. Moreover, the volcanic rocks in the east were derived from a relatively deeper mantle source (thick lithosphere) due to their smaller rifting.

The Shijia gold deposit, classified as a Linglong-type (quartz vein-type) gold deposit, is located in the north of Qixia-Penglai gold belt in the Jiaodong Peninsula. The orebodies predominantly occurring as quartz-sulfide veins are hosted in the Early Cretaceous Guojialing amphibole-bearing monzogranite and strictly controlled by NNE- to NE-striking high-angle faults. Hydrothermal minerals include K-feldspar, quartz, sericite, pyrite, sphalerite, galena, chalcopyrite, calcite and fluorite. Based on the mineralogical, textural and field cross-cutting relationships, the mineralization process can be divided into three stages: (I) quartz-sericite-pyrite stage, (II) quartz-sulfide-gold stage and (III) quartz-calcite-fluorite stage. Field investigation shows that the orebodies have undergone several times of deformation after their formation, resulting in the deformation and discontinuity of the orebodies. Early Cretaceous dykes, including granite pegmatite, lamprophyre, diabase and granite porphyry, are developed in the Shijia gold deposit. The crosscutting relationship between orebodies and various mafic-felsic dykes shows that their formation sequence is granite pegmatite, Au orebody, lamprophyre, diabase and granite porphyry. LA-ICP-MS zircon U-Pb dating shows that the emplacement ages of granite pegmatite, lamprophyre, diabase, and granite porphyry are 129.7 +/- 1.6 Ma, 129.3 +/- 1.4 Ma, 128.3 +/- 1.3 Ma and 120.0 +/- 1.1 Ma, respectively. These dating results are consistent with the crosscutting phenomenon observed in the field, indicating that the mineralization time of the Shijia gold deposit is between 129.7 Ma and 129.3 Ma. The timing of gold mineralization at Shijia coincides with the large-scale thinning of the lithosphere in the North China Craton during the Early Cretaceous, indicating that the formation of the deposit is mainly controlled by extensional tectonics. Because the gold mineralization was predated the emplacement of lamprophyre and diabase dykes, there might be not a direct genetic relationship between the gold mineralization and the mafic dykes in the Shijia gold deposit.