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East Junggar is an important part of the Central Asia Orogenic Belt and has developed a multi‐epoch and multi‐type metallogenic system. Yundukala is a recently discovered large intrusion‐related Au–Cu–Co deposit. The No. 1 main mineralization zone mainly occurs in the contact area between fine‐grained diorite and basalt. Massive and vein mineralization have developed there, but the ore‐bearing stratum, ore‐bearing intrusive rocks, and metallogenic ages are not clear. Zircon SHRIMP U–Pb dating of the porphyritic diorite and fine‐grained diorite yields ages of 416.1 ± 3.9 Ma and 411.1 ± 7.5 Ma, respectively. The dioritoid intruded into the ore‐bearing stratum, indicating that this formation is part of the Early Palaeozoic strata rather than the Middle Devonian Beishan Formation. The Re–Os isochron age of the chalcopyrite in the massive mineralization is 402.6 ± 5.2 Ma; thus, the massive mineralization is related to fine‐grained diorite and formed in the Early Devonian. Six sulphides and four sulphides from the vein mineralization yield Re–Os isochron ages of 352.8 ± 1.8 Ma and 354 ± 23 Ma, respectively, and the limited vein mineralization was formed during 353–354 Ma. The massive and vein mineralizations in the Yundukala deposit were formed in the Early Devonian and Early Carboniferous. [ABSTRACT FROM AUTHOR]

The Tudigou porphyry Cu deposit is located in the central part of the southern Qinling belt. Copper mineralization is closely associated with monzogranite porphyry. Zircon LA–ICP–MS U–Pb dating of monzogranite porphyry suggests that the ages of magmatism at Tudigou vary between 150 ± 1 and 148 ± 1 Ma and overlap with the molybdenite Re–Os age of 150–148 Ma, indicating that the Tudigou intrusion and associated mineralization formed during the Late Jurassic. The enrichment in large‐ion lithophile elements, depletion in high‐field‐strength elements, high Ba/Th and La/Yb ratios, and negative correlation between Dy/Yb and La/Sm ratios, together with narrow ranges of εHf(t) values (εHf(t) = −4.0 to +1.4) suggest monzogranite porphyry was derived from a metasomatized lithospheric mantle with minor crustal components contribution, which is also evidenced by the lead isotopic result. The La/Yb ratios of 30 Mesozoic plutons in the southern Qinling belt were used to calculate the Moho depth, which suggests that the magmatism and mineralization in the region occurred during lithosphere thinning in response to the tectonic transition from compression to extension transitional regime. The calculated oxygen fugacity of the Late Mesozoic porphyry deposits in the Qinling–Dabie orogen have identical ΔFMQ values (averaging +1.4 to +2.4). However, the V/Sc ratios (the proxy for water content) are distinct among different deposit sizes, indicating that the dissolved water in the magma plays a critical role in porphyry‐type mineralization. [ABSTRACT FROM AUTHOR]

Northwest Hebei province is one of the gold-producing areas in China. Based on a geochronological analysis of the Zhangjiakou-Xuanhua area, zircon U–Pb with an age of 2487–142 Ma and zircon fission-track (ZFT) with a cooling age of 155–66 Ma were obtained. Zircon U–Pb dating of the Xiaoyingpan deposit revealed two ages of 2487 ± 92 Ma and 1745 ± 89 Ma, representing the Archaean and Early Proterozoic metamorphism of the Sanggan Group. The ZFT cooling age of 155 ± 10 Ma represents the deposit's lower limit metallogenic age. The Shuiquangou (SQG) alkaline complex emplaced at 388.9 ± 3.0 Ma and experienced magmatic activities until the Late Devonian (ca 377 Ma), considering the response to the collision between the Siberian plate and the North China Craton. The emplacement age of Shangshuiquan (SSQ) granite is 142.3 ± 1.1 Ma and is coeval with the thinning of the North China Craton during the Late Jurassic–Early Cretaceous. The intrusion of SSQ might partially reheat the SQG complex, resulting in the Yanshanian gold mineralization in Dongping. The SQG complex and SSQ granite underwent a relatively consistent rapid cooling process in the Cretaceous based on the ZFT ages. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two hydrothermal mineralization events in this deposit are identified: quartz-sericite-pyrite-native gold (I) stage and chlorite-quartz-sericite-chalcopyrite-electrum (stage II). • This study provides additional age constraints on the host rocks (Caledonian granitic rocks) in the Hebaoshan area, with ages ranging from 441 to 446 Ma, as well as two mineralization events at approximately 238.46 ± 2.01 Ma and 179.54 ± 7.28 Ma. • The combination of ages and geological evidence suggests that the first mineralization event is associated with the intracontinental orogeny of the Yangtze Block and Cathaysia Block, as well as the flat subduction of the Paleo-Pacific Plate. The second mineralization event is related to the extensional tectonic activity following the collision between the Yangtze Block and Huaxia Block. The Hebaoshan gold deposit (41.5 t Au @ 3.5 g/t) is located in the southeastern region of the South China Block, central part of the Wuyishan metallogenic belt. The ore-hosting rocks in this area are predominantly Precambrian metasedimentary rocks and Caledonian granitic rocks. Two hydrothermal mineralization stages can be distinguished: a quartz-sericite-pyrite-native gold (stage I) and a chlorite-quartz-sericite-chalcopyrite-electrum (stage II), with hydrothermal monazite and rutile are firstly identified in separate stages. The complex geological history of the region has resulted in ongoing debates regarding the age of gold mineralization and the genesis of the major gold deposits in this area. In order to precisely constrain the mineralization age of the deposit and further establish a genetic model for the ore deposit, LA-ICP-MS U-Pb dating and trace element analysis on accessory minerals were conducted. Based on the textures mineral assemblages, and geochemical features of the accessory minerals, magmatic apatite, hydrothermal rutile, and both magmatic and hydrothermal monazite were identified. The U-Pb ages of magmatic apatite and monazite are determined to be 445.3 ± 15.80, 441.3 ± 15.10 Ma and 446.57 ± 1.03 Ma, respectively, suggesting that these ages represent the emplacement ages of the Caledonian intrusive rocks. The ages of hydrothermal monazite and hydrothermal rutile are determined to be 238.46 ± 2.01 Ma (single-mineral analysis), 238.46 ± 2.01 Ma (in-suit analysis) and 179.54 ± 7.28 Ma, respectively, suggesting that represent two mineralization events during the Late Triassic to early Jurassic in the Hebaoshan area. These data provide new constraints on the mineralization process in the Hebaoshan deposit and excludes the link between gold mineralization and the intrusion of the Caledonian granites. Regionally, It is speculated that the two mineralization events at Hebaoshan are respectively associated with intracontinental orogenic movements between the Yangtze Block and Cathaysia Block, the flat-slab subduction of the Paleo-Pacific Plate (stage I), and the subsequent extensional tectonics related to the collision between the Yangtze Block and Cathaysia Block (stage II). Our study indicates that the timing of multiple episodic mineralization can be constrained by analysis of accessory minerals, which provides a geological basis for better genetic model for the deposit and provide geological evidence for unraveling the relationships between magmatic activities and mineralization events in the region. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magmatic and metamorphic columbite crystallized at 1359 ± 31 Ma, 346 ± 18 Ma and 284 ± 16 Ma, respectively. • The niobium in Bayan Obo is sourced from Mesoproterozoic carbonatite. • Local enrichment of niobium is attributed to the process of fenitization. • Nb and REE mineralization display spatial and temporal coupling in Bayan Obo deposit. The Bayan Obo deposit is world-famous for its giant rare earth reserves, and also accompanied with 2.2 Mt Nb 2 O 5 resources at an average grade of 0.13 %, renowned as the second largest Nb deposit globally. Previous studies have focused on the origin of carbonatite (igneous/sedimentary), and variation composition during evolution, as well as its super-enrichment of light rare earth elements (LREE), while the metallogenic mechanism of niobium is being overlooked despite the identification of plenty Nb-bearing minerals. In this study, we identify four types of columbite as major Nb-bearing minerals, instead of pyrochlore in the west pit of Bayan Obo. Detailed mineralogical study has revealed large primitive columbite (Clb1-I, 100–200 μm) is hosted in the coarse-grained Fe-dolomite carbonatite (FeO = 5.46–10.47 wt%), being an ideal target for future mineral beneficiation. Those columbites (Clb1-I) are featured by lowest Sr, Y, and ∑REE but enriched in iron in composition, revealing its magmatic origin. Sieve-textured columbite (Clb1-II, ∼100 μm) dispersed in the fluorination and chloritization dolomite carbonatite, with a U–Pb age of 1359 ± 31 Ma, contemporary with ages of the regional carbonatite magma intrusion and rift-related magmatism, indicating niobium being sourced from mantle-derived carbonatite. The occurrence of fluorite as inclusions in Clb1-I indicates the solubility of Nb was enhanced by fluxes, and the columbite saturation was easily achieved during the carbonatite magma evolution into ferroan carbonatite. Strong fenitization metasomatism further locally concentrated columbite either within the mineral assemblages of pyrite + phlogopite + allanite (Clb2) or in the mica-dominated fenite (Clb3), and crystallized at 346 ± 18 Ma and 284 ± 16 Ma, respectively. The latter metalogenetic epoch is accordant with late Permian granitic magmatism event (ca. 280 Ma) while the former age may attribute to its occurrences related to the early Paleozoic arc-continent collision. Differ from pristine columbite (Clb1-I and Clb1-II), the metamorphic columbite (Clb2 and Cl3, especially Clb3) are enriched in Ta (1803–4092 ppm), Y (560–2029 ppm) and ∑REE (720–6317 ppm) content, probably suggesting the highest degree of evolution. The similar metallogenesis framework between Nb and REE, combined with the coexistence of columbite and REE minerals assemblages, implies the spatial and temporal coupling of Nb and REE mineralization. This first innovative and systematic mineralogical and geochronological work directly constrains the nature of Mesoproterozoic mantle-derived carbonatite with fertile Fe and fluxes, and the Paleozoic and Permian fenitization metasomatism, are the major factors contribute to the metallogenic specialization of niobium in Bayan Obo. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two episodes of garnet and Fe mineralization were identified at Jia'erbasidao Fe deposit. • The 1st garnet generation was formed at 270.6 Ma and skarn related. • The 2nd garnet generation was formed at 248.3–246.0 Ma and skarn related. Over a hundred iron ore occurrences have been discovered in the Chinese Altay Orogenic Belt (AOB), which is a key Fe-ore belt in NW China. In the Jia'erbasidao ore district, Fe skarn mineralization was mainly developed along the contact zone between biotite granite and the marble of Altay Formation, which is different from most Fe mineralization (non-skarn contact zone) in the Chinese AOB. Two generations of garnet (Grt1and Grt2) have been identified to be related to the two stages of Fe-ore formation at Jia'erbasidao, and Grt1 and Grt2 can be further divided into Grt1a, 1b and Grt2a, 2b, respectively. Our U-Pb dating indicates that the biotite granite and garnet from prograde skarn stage 1 (Grt1a) were formed at 275.6 ± 3.1 Ma and 270.6 ± 4.4 Ma, respectively. The mineralized biotite granite is metaluminous to peraluminous, LREE-enriched and HREE-depleted. Meanwhile, two Grt2a samples from the prograde skarn stage 2 yielded lower intercept 206Pb/238U ages of 248.3 ± 2.9 Ma and 246.0 ± 6.0 Ma, respectively. Grt1 and Grt2 may have formed from different ore-forming fluids: Grt1a was precipitated from a LREE-depleted, near neutral and low f O 2 fluid (δEu = 1.92–2.84); Grt1b and magnetite (Mag1) were precipitated from the same fluid with higher f O 2 (δEu = mostly 1.22–2.63); Grt2a was precipitated from a fluid with relative LREE enrichment, relatively lower pH and higher f O 2 (δEu = 0.98–1.69); Grt2b and magnetite (Mag2) was formed from a fluid that was HREE-enriched, near neutral, and higher f O 2 (δEu = 0.76–1.09). Our study shows a two-stage Fe mineralization at Ja'erbasidao, including the Early Permian Fe skarn mineralization and the Early Triassic skarn mineralization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zircon U-Pb dating results refine the emplacement age of the Xikeng pluton at 232.2 ± 1.1 Ma. • Cassiterite and wolframite U-Pb dating constrains the timing of W-Sn mineralization from Xigkeng deposit at 228.4 ± 0.90 Ma and 227.8 ± 1.60 Ma, respectively. • Source of magmatic materials was derived from reworking of crustal materials under an extensional setting. The Chongyi–Shangyou–Dayu ore-concentrated district represents one of the most important wolframite production bases in China, and most of the W-Sn deposits formed in the early Yanshanian period. The Xikeng quartz vein-type W-Sn deposit is located spatially not far from the Triassic Keshuling granitic pluton. The deposit contains 43 ore-bearing quartz veins, in which the ore minerals are mainly cassiterite and wolframite. These ore veins are concentrated in the Sinian metasandstone and sandy slate of the Laohutang Formation and extend down to the top of the concealed granite. The concealed intrusion is composed of medium- to fine-grained muscovite granites, which relate to the Indosinian Keshuling granite, according to geophysical data. Zircon grains from the concealed Xikeng granitic intrusion have a concordant U-Pb age of 232.1 ± 1.1 Ma (MSWD = 0.9). The zircon εHf(t) values range from −11.0 to −7.9, indicating primary reworking of the ancient crustal materials. Wolframite and cassiterite grains yield Tera-Wasserburg concordia intercept ages of 228.4 ± 0.9 Ma (MSWD = 1.2) and 227.8 ± 1.6 Ma (MSWD = 0.3) for the Xikeng deposit, respectively. These data demonstrate that the Indosinian W-Sn mineralization events were genetically related to granitic magma activities that share similar magmatic sources with the Yanshanian W-Sn mineralization-associated granitic intrusions. Combined with previous robust granitic and metallogenic ages, this paper identifies a new Indosinian W-Sn mineralization event in southern Jiangxi Province, Nanling Range. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three stages of W-Sn mineralization in the Xitian Ore Field have been identified. • Triassic skarn-type mineralization occurred in a relatively closed metallogenic system. • Jurassic quartz vein-type mineralization occurred in an open system with addition of meteoric water. • Deeply buried Early Cretaceous magmatic-hydrothermal deposits may exist in the Xitian Ore Field. • Evolution from skarn-type to vein-type mineralization was related to tectonic environment changing. The Nanling Metallogenic Belt is a major W-Sn province in South China containing numerous ore deposits formed during a complex history of magma emplacement and mineralization. The Xitian ore field in Hunan Province is a typical example of a late magmatic-metallogenic system. In this study, garnets from skarn-type ores in the Xitian ore field yield a U-Pb age of 231.7 ± 1.3 Ma (n = 33), whereas cassiterite grains from quartz vein-type ores give U-Pb ages of 158 to 154 Ma (n = 72) and 140.7 ± 3.3 Ma (n = 6), suggesting three stages of W-Sn mineralization (Late Triassic, Late Jurassic, and Early Cretaceous). In the Late Triassic skarn-type ores, the REE patterns of scheelite change from MREE-enriched to LREE-enriched with time, whereas the REE patterns of scheelite shift from MREE-enriched to MREE-depleted in the Late Jurassic quartz vein-type ores, indicating diverse metallogenic processes. Differences in the Y/Ho ratios and Sr-O isotope compositions of scheelite further confirm discrete metallogenic pathways for the Late Triassic skarn-type W ore and the Late Jurassic quartz vein-type ore, with fluid-rock interaction of the former dominated by magmatic-hydrothermal fluids whereas the latter was influenced by large amounts of meteoric water. A model emphasizing the evolution from skarn-type to vein-type metallogeny is proposed to account for the complex genesis of multistage W–Sn deposits related to the Xitian granite complex. More generally, this study demonstrates that in-situ LA-ICP(MC)-MS U-Pb dating and isotopic analysis of hydrothermal minerals are powerful tools to decipher the nature, timing, and evolution of multistage W-Sn metallogenic systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • U-Pb dating of syn -ore monazite and xenotime constrains the Xiayu Ag-Pb-Zn-Au(-Cu) mineralization age to be 125.7±1.8 Ma to 123.3±1.7 Ma. • Detailed geological characteristics indicate there are genetic connections among granite porphyry, breccia pipe, and steeply-dipping Ag-Pb-Zn-Au(-Cu) veins. • The Xiayu Ag-Pb-Zn-Au(-Cu) mineralization is the first recognized intermediate-sulfidation epithermal deposit in the world-class East Qinling porphyry Mo ore belt. Porphyry Cu deposits are often temporal-spatial-genetically associated with epithermal polymetallic (Ag-Pb-Zn-Au-Cu) veins in some important metallogenic belts, forming a porphyry–epithermal ore systems. However, the genetic type of the large-scale vein-type Ag, Pb, Zn and Au mineralization in the world-class East Qinling porphyry Mo ore belt (Central China) has not been delineated. Here, we provide a case study of the Xiayu orefield as an example for a typical intermediate-sulfidation epithermal Ag-Pb-Zn-Au(-Cu) deposit. The Xiayu Ag-Pb-Zn-Au(-Cu) orefield, the largest Ag producer in the East Qinling ore belt, contains the Haopinggou Ag-Pb-Zn-Au, Shagou Ag-Pb-Zn, Tieluping Ag-Pb(-Cu), and Houzhanggou Ag(-Cu) deposits, which share similar geological characteristics. The Ag-Pb-Zn-Au(-Cu) mineralization occurs as open-space fillings, veins and local hydrothermal breccias and stockworks, infilled with carbonates (siderite, ankerite, and calcite), quartz, pyrite, sphalerite, galena, chalcopyrite, tetrahedrite, electrum, silver minerals (argentiferous tetrahedrite, stromeyerite, pyrargyrite, polybasite, argentite and native silver). The vein crosscutting and overprinting relationships indicate four hydrothermal stages: (I) siderite-pyrite-quartz-electrum ± magnetite, (II) dark-brown sphalerite-siderite-quartz ± galena, (III) galena-tetrahedrite-chalcopyrite-silver minerals-ankerite-quartz ± light-brown sphalerite, and (IV) ankerite-calcite-chalcedony-fluorite. Mineral zoning at the orefield-scale is recognized from north to south: pyrite, sphalerite-galena, and tetrahedrite-native silver, which corresponds to ore metal zoning from Au ± Zn to Zn-Pb-Ag and Cu-Ag. The Haopinggou granite porphyry consists of the megacrystic granite porphyry (P1) and granite porphyry (P2), which were emplaced at 134.6±1.2 Ma and 125.9±0.7 Ma, respectively. Anhedral monazite (Mon1) encapsulated in pyrite and siderite from stage I of the Haopinggou and Shagou deposits constrains the early hydrothermal activity at 133.3±1.0 Ma. U-Pb dating of syn -ore monazite (Mon2) and xenotime (intergrown with electrum, galena, sphalerite and quartz) from the Shagou, Haopinggou, and Tieluping deposits constrains the Ag-Pb-Zn-Au(-Cu) mineralization age to be 125.7±1.8 Ma to 123.3±1.7 Ma. The consistency of the magmatic and mineralization ages indicates that the magmatic-hydrothermal process may have played an important role in the Ag-Pb-Zn-Au(-Cu) mineralization. Gold distribution, mineral association, and geochronological data, all suggest that the Au and Zn-Pb-Ag ores were formed from the same mineralization event rather than two discrete mineralization events as previously suggested. Considering the geological characteristics, metal zoning, mineralization ages, mineral chemical composition and published data of fluid inclusion, we conclude that the Xiayu Ag-Pb-Zn-Au(-Cu) veins belong to typical intermediate-sulfidation epithermal mineralization and further propose a porphyry–breccia–intermediate-sulfidation epithermal Ag-Pb-Zn-Au(-Cu) mineralization system. It is the first reported intermediate-sulfidation epithermal mineralization in the East Qinling ore belt, which implies that the epithermal mineralization may have been developed in the world-class East Qinling porphyry Mo ore belt. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Songshan tin deposit occurred at the end of Late Cretaceous, not in Triassic as previous suggested. • The end of Late Cretaceous is another important tin metallogenic period in the Lancangjiang tin belt. • The tin mineralization not only can occur in the magmatic arc, but also in the hinterland behind the magmatic arc. The Songshan tin deposit is located in the northern Lincang granitic batholith along the Lancangjiang tin belt, Western Yunnan, southwestern China. The ore bodies mainly occur as tourmaline-quartz veins with NNE- and/or NW-trending in the Triassic Pinghejie granitic pluton, and the schist of the Proterozoic Songshan Formation. The previous study suggested the tin mineralization in the Songshan deposit should occur in the Triassic, but no directed age data support it. This hinders the understanding of the genesis of the Songshan tin deposit, especially the tin mineralization in the Lancangjiang tin belt. Here, we report the zircons U-Pb ages of 222.7 ± 1.6 and 222.0 ± 2.4 Ma for the granodiorite, 215.1 ± 1.5 and 223.0 ± 2.0 Ma for the biotite monzogranite, and 222.3 ± 2.3 Ma for the alter granite from the Pinghejie granitic pluton. The monazite from the monzogranite yields a U-Pb age of 212.8 ± 1.9 Ma. We also obtain two garnet U-Pb ages of 215.1 ± 8.7 Ma and 213.5 ± 7.2 Ma from skarn, and two cassiterite U-Pb ages of 76.6 ± 1.5 Ma and 79.6 ± 3.6 Ma from tin ores. These data suggest that tin mineralization in the Songshan deposit occurred at the end of Late Cretaceous, which is quite different from the ages of the Pinghejie granitic pluton emplaced and the formation of skarn. The zircon Hf isotopes (εHf(t) = –22 ∼ -12) and monazite Nd isotopes (εNd(t) = -13.04 ∼ -11.80) indicate that the Pinghejie granitic pluton was derived from the remelting of Paleoproterozoic crust. The paper concluded that the tin mineralization in the Songshan deposit occurred at the end of Late Cretaceous. It is another important metallogenic period in the Lancangjiang tin belt, which may be related to the subduction of the NeoTethys oceanic crust. The tin mineralization can not only occur in the magmatic arc, but also in the hinterland behind the magmatic arc. [ABSTRACT FROM AUTHOR]

[Display omitted] • LA-ICP-MS monazites analysis confirms the emplacement of two-mica monzogranites occurred in ∼ 221.7–218.2 Ma. • W mineralization in Zanshi shows accordant mineralization age of ∼ 218.7–215.1 Ma. • A new Late Triassic W mineralization and magmatism are recognized. • the cooling rate of the ore-forming hydrothermal system may be a key controlling factor of ore grade. The Nanling metallogenic belt is rich in critical metal minerals, e.g., tungsten, tin, and rare earth element (REE). The newly discovered Zanshi tungsten deposit, located at the northeastern part of the Nanling metallogenic belt, has drawn great attention from geologists for its rare Triassic magmatic-hydrothermal event in this region. Based on detailed field work, a series of geochemical and geochronological analyses, including whole-rock geochemical analyses consisting of major and trace elements, LA-ICP-MS monazite U-Pb dating of the granites and quartz Rb-Sr and muscovite 40Ar-39Ar isotopic dating of the ore-bearing quartz veins, were carried out in this study, aiming to constrain the rock- and ore-forming ages of the deposit as well as the petrogenesis of granites. The whole-rock geochemical analyses, the medium to fine-grained two-mica monzonitic granites in the Zanshi tungsten deposit are peraluminous S-type granites and derived from the partial melting of metamorphic graywackes in a post-collisional extensional tectonic setting. The LA-ICP-MS monazite U-Pb dating on the two medium- to fine-grained two-mica monzonitic granite samples yields weighted average ages of 218.2 ± 1.2 Ma (MSWD = 1.3) and 221.7 ± 1.7 Ma (MSWD = 2.7), respectively. These ages are consistent with the quartz Rb-Sr and muscovite 40Ar-39Ar isotopic ages of the ore-bearing quartz veins, which are 218.7 ± 3.2 Ma and 215.1 ± 2.0 Ma, respectively, revealing that the tungsten mineralization in this deposit is related to the Triassic magmatic-hydrothermal activity. Combined with previous studies, the Zanshi tungsten deposit likely experienced about 5 M.y. of magmatic evolution and 3.6 M.y. of mineralization. Meanwhile, the cooling rate of the ore-forming fluids of this deposit was about 111 °C/M.y., which may be regarded as a controlling factor which affects the ore grade of the deposit. [ABSTRACT FROM AUTHOR]