Search

The Shuikoushan ore field is one of the largest Pb-Zn-Au polymetallic magmatic hydrothermal system in South China and hosts a significant metallogenic potential. The Kangjiawan gold deposit is a low-temperature hydrothermal vein-type gold deposit developed on the periphery of the ore field. Geological chronology suggests that the gold mineralization of the Kangjiawan deposit is coeval with the emplacement of the Shuikoushan granodiorite and related Pb-Zn mineralization. In addition, trace elements characteristics and a narrow δ34S range of -2.94‰ ∼ +3.03 ‰ of pyrite, indicate that ore-forming materials were mainly derived from granitic magmas. Based on the spatial distribution between the ore deposits and granitic intrusions, it is suggested that the Kangjiawan Au deposit is probably as the distal products of magmatic-hydrothermal systems of the deep concealed granitic pluton. The deep parts of the Kangjiawan Au deposit have potential for high-temperature skarn-type mineralization associated with concealed intrusion. Conversely, there is potential for low-temperature Au mineralization linked to the Shuikoushan Granodiorite in the periphery of the Shuikoushan ore field. [Display omitted] • Calcite U-Pb data support that gold mineralization at Kangjiawan occurred at 151.7 ± 5.4 Ma in late Jurassic. • Trace element analysis and S isotope compositions reflect that Kangjiawan gold deposit is genetically linked to granitic magmas. • The Kangjiawan deposit represents distal products of magmatic-hydrothermal systems associated with a deeply concealed granitic pluton. (Meta)sedimentary rock-hosted gold (Au) deposits are globally important Au resources, of which ore genesis and mineral exploration have been attracted considerable attention. However, the precise dating of Au mineralization of those Au deposits remains challenging due to the absence of suitable dating minerals, thus impeding a comprehensive understanding of their genesis. The Kangjiawan Au deposit, situated in the southern Hunan Province, South China, is one of representative (meta)sedimentary rock-hosted Au deposits. Due to the lack of mineralization age, the genesis of Kangjiawan Au deposit is still a matter of debate. Here we report the data of in situ calcite U-Pb dating, in situ trace elements and sulfur isotope analysis of pyrite, to further constrain the mineralization timing and the sources of ore-forming materials of the Kangjiawan Au deposit. Based on the detailed field investigation and petrographic observations, three mineralization stages have been identified: pyrite (Py1) + quartz (Stage I), gold-bearing pyrite (Py2) + polymetallic sulfides + quartz + calcite (Stage II), and gold-bearing pyrite (Py3) + calcite (Stage III). The results of mineralogical and trace elemental analyses indicate that Au are mainly hosted in Py2 (average 14.19 ppm) and Py3 (average 4.80 ppm), primarily as the form of "invisible gold". In situ LA-ICP-MS U-Pb dating on calcite intergrowth with the gold-bearing pyrite (Py3) yields a Tera-Wasserburg lower intercept age of 151.7 ± 5.4 Ma. This age is well consistent with the published zircon U-Pb age (158.3 ± 1.2 Ma) of the nearby Shuikoushan granodiorite, the molybdenite Re-Os age (157.8 ± 1.4 Ma) of the Laoyachao skarn Pb-Zn deposit in the Shuikoushan ore field, and the garnet U-Pb age (159.1 ± 1.9 Ma) of the skarn Pb-Zn ore in depth of the Kangjiawan Au deposit. These suggested that the Au mineralization of the Kangjiawan deposit is coeval with the emplacement of the Shuikoushan granodiorite and Laoyachao Pb-Zn mineralization, which are important parts of the large-scale Middle-Late Jurassic Cu-Au-Pb-Zn Metallogenic event of the Qin-Hang Metallogenic Belt, South China. In addition, trace elemental contents, such as relative low Co, Ni, and Se (i.e., <0.01 to 100 ppm), and a narrow δ34S range of −2.94 ‰ ∼ +3.03 ‰ of pyrite, indicate that ore-forming materials were mainly derived from granitic magmas. Integrated with previous studies, it is suggested that the Au mineralization in the Kangjiawan deposit is genetically associated with the late Jurassic granitic magmatism and is probably as the distal products of the deep-seated concealed granitic intrusions and related proximal skarn Pb-Zn ore. [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] • The host granite belongs to the ca. 1860 Ma Donington Suite. • The host granite experienced a thermal event (>350 °C) at ca. 1770 Ma. • Porphyritic volcanic units and polylithic breccias formed at ca. 1590 Ma. • Iron Oxide Copper-Gold mineralisation formed at ca. 1585 Ma. • Uranium mineralisation, post-ore veining and late alteration formed at ca. 600–500 Ma. The Carrapateena Iron Oxide Copper-Gold (IOCG) deposit is located on the eastern margin of the Gawler Craton, approximately ∼475 km NE of Adelaide, South Australia. The deposit is hosted within a granite belonging to the Donington Suite and contains various polylithic breccias and intrusive volcanic units. Multiple stages of alteration/mineralisation are present throughout the deposit, which includes: (1) pre-mineralisation alteration; (2) hematite I; (3) Cu-Au mineralisation; (4) hematite II & REE mineralisation; (5) uranium mineralisation; (6) post-mineralisation alteration/veining. In order to establish a temporal framework, multi-mineral U–Pb geochronology was conducted on a variety of lithologies throughout the deposit and across multiple stages of alteration/mineralisation. Zircons from the host granite are predominantly discordant, with two concordant analyses from two samples producing 207Pb/206Pb ages of ca. 1880–1861 Ma, consistent with the emplacement of the Donington Suite (1860–1850 Ma). Apatite U–Pb geochronology performed on the granite-bearing samples produced ages of ca. 1775–1767 Ma, indicating the presence of a moderate temperature (≥350 °C) thermal event approximately 100 Ma after the crystallisation of the host rock. Zircon U–Pb geochronology conducted on a porphyritic volcanic unit and two polylithic breccia samples produce bi-modal age populations at ca. 1880–1860 Ma & ca. 1590 Ma. The ca. 1880–1860 Ma age reflects zircons inherited from the host granite, while the younger ca. 1590 Ma population represents the crystallisation age of the porphyritic volcanic unit and the maximum formation age of the polylithic breccias. U–Pb geochronology conducted on apatite, hematite and xenotime associated with various stages of mineralisation produce ages of ca. 1585 Ma, consistent with a major Fe-Cu-Au metallogenic event throughout the Gawler Craton. U–Pb geochronology performed on uraninite, apatite located within a late vein, and "vuggy" hematite records a second hydrothermal event from ca. 600–500 Ma, reflecting a period of minor deformation and deposit-wide fluid circulation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The magmatic-hydrothermal system of Yangla skarn Cu deposit is relatively reduced. • The barren quartz porphyry was also originated from reduced magmas and thus less fertile for porphyry Cu formation. • Intense fluid-carbonate rocks interaction and fluid focusing could be the key to formation of the reduced Yangla Cu deposit. In the Paleo-Tethyan orogenic belt, reduced mineralization systems result in extensive saturation and segregation of magmatic sulfide phases, which in turn leads to the loss of chalcophile elements and hinders the precipitation of large amounts of copper. As a result, porphyry Cu deposits are rare within the belt. In this contribution, we investigate the composition of zircons from the granodiorite, fluid inclusions and hydrothermal scheelite from orebodies of the Yangla Skarn Cu deposit, and assess the magmatic-hydrothermal redox state of the system. The igneous zircons from ore-causative granodiorite have negative Eu anomalies (Eu N /Eu N * = 0.27 ± 0.03, n = 11) and the calculated ΔFMQ values are -0.23 ± 0.31 (n = 11). The ore-forming fluids in the pre-ore stage was rich in CH 4 , and precipitating hydrothermal scheelite in the syn -ore stage with low Mo contents (Mo = 17.4 to 149 ppm, mean 57.7 ppm) and positive Ce anomalies (Ce N /Ce N * = 1.14 ± 0.06, n = 29). The geochemistry suggests that the magmatic-hydrothermal system at Yangla is relatively reduced, consistent with the abundant development of pyrrhotite in the ore body. In addition, we have carried out zircon SIMS U-Pb dating and trace analysis of the barren quartz porphyry in the Yangla ore field, which gives an emplacement age of 227 Ma and is also derived from reduced magmas (ΔFMQ = -1.27 ± 0.55; Eu N /Eu N * = 0.32 ± 0.10, n = 7) that were less fertile for porphyry Cu formation. By comparing with the barren quartz porphyry, we suggest that the key control of the skarn ore body may have been that the low-permeability of carbonate units seal the mineralizing fluids, enhancing fluid-carbonate reactions and concentrating the sulfides in a relatively small area. Without these processes, it can only form barren porphyry system. We highlight that, unlike typical porphyry Cu deposits, intense fluid-carbonate rocks interaction and fluid focusing could result in skarn Cu formation, even though in relatively reduced magmatic-hydrothermal conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Diverse W metallogeny of the Baiyunxian ore field intensively occurred in 156–153 Ma. • W metallogeny was associated with Late Jurassic highly evolved magmatic phases. • Metal element are derived from remelting of metasedimentary crustal basement. • Lithology of wall rocks is the major cause of varied W mineralization types. The Baiyunxian ore field, a large tungsten ore filed in the Nanling Metallogenic Belt of South China, hosts a variety of tungsten deposits such as the Dapu (quartz wolframite vein type), Chashanjiao (skarn type), Toutianmen (greisen type), and Dashan (quartz scheelite vein type). However, precise mineralization ages of these deposits remain poorly constrained and this has long vexed a better understanding of genetic relationships between diverse W mineralization types and the spatially associated Jiufeng granitic complexes. Here, we report firsthand zircon U–Pb, monazite U–Pb, garnet U–Pb, cassiterite U–Pb, and molybdenite Re–Os ages of different granites and ores from the Baiyunxian ore field. The Jiufeng granitic complexes consists of phase Ⅰ biotite granite (P1), phase Ⅱ two-mica granite (P2), and phase Ⅲ granitic dikes (P3, including greisen W ore). Zircons from P1 granite define a concordant U–Pb age of 166.0 ± 0.9 Ma (MSWD = 1.1). Monazites from P2 granite yielded a Tera–Wasserburg lower intercept age of 159.2 ± 0.7 Ma (MSWD = 0.45). In addition, zircons and monazites from P3 granite in the Toutianmen deposit yield a concordant U–Pb age of 154.7 ± 1.3 Ma (MSWD = 1.3) and a Tera–Wasserburg lower intercept age of 156.6 ± 1.9 Ma (MSWD = 0.14), respectively, suggestive of multi-stage emplacement processes of the Jiufeng complexes. Ten molybdenite samples from the Dapu deposit generate an isochron age of 156.0 ± 3.0 Ma (MSWD = 0.93). In situ garnet and cassiterite LA-ICP-MS U–Pb dating results of the Chashanjiao skarn deposit yield lower Tera–Wasserburg intercept ages of 155.3 ± 1.2 Ma (MSWD = 1.6) and 153.4 ± 3.7 Ma (MSWD = 1.3), respectively. These dating results indicate that different W mineralization events in the Baiyunxian ore field intensively occurred in the Late Jurassic (∼159–153 Ma). Despite a close spatial relationship between various W orebodies and P1 granite, the geochronological results demonstrate that extensive W metallogeny in the Baiyunxian ore filed likely occurred later than P1 granite and contemporaneous with P2–3 granites. In addition, scheelites from the four deposits have similar REE patterns that are characterized by weak MREE enrichment, despite few exceptions being found in scheelites from the Dashan and Chashanjiao deposits. This suggests that the diverse W metallogeny in the Baiyunxian ore field were derived from the same magmatic hydrothermal system and changed as the ore-forming fluid evolved. Multidisciplinary evidence indicates that the Late Jurassic highly evolved P2–3 granites of the Jiufeng complexes were crucial to W mineralization in the Baiyunxian ore field and the lithology of wall rocks exerted first-order control of W mineralization types. [ABSTRACT FROM AUTHOR]

[Display omitted] • Garnet U-Pb dating constrains the age of the Lazhushan deposit at ca. 150 Ma. • Fe skarn mineralization in the Edong district started earlier than previously thought. • The Th/U ratio of garnet is a potential redox indicator of ore fluids. Garnet is ubiquitous in skarn deposits. It is a sensitive recorder of physiochemical conditions and also a powerful geochronometer. In this study, we use garnet trace element geochemistry and U-Pb geochronology as well as sulfur isotopes of sulfides to constrain the age and mineralization process of the Lazhushan Fe skarn deposit. Garnets in the Lazhushan Fe skarn belong to the andradite-grossular solution series and yield a compositional range from Adr 47.2 Gro 50.7 to Adr 97.4 Gro 0.9. There are strong correlations between La N /Yb N ratios and andradite contents in garnet, indicating that garnet major element composition exerts a strong control on the REE fractionation. The decrease of HFSEs (Nb, Ta, Zr, Hf, and Ti) and Co, V, and Mn concentrations from prograde to retrograde garnets may reflect increasing water/rock ratio and decreasing temperature during skarn evolution, respectively. Co-precipitation with magnetite may be responsible for the low concentration of V in the retrograde garnets. The Th/U ratio increase from endoskarn garnet to exoskarn counterparts, probably reflecting an increase of fluid f O 2 due to interactions with evaporate sulfate from the wall rocks. The sulfides in this deposit are enriched in δ34S (up to 13 ‰), conforming the involvement of evaporate sulfate during Fe skarn mineralization. The incursion of evaporate sulfate may have played an important role in magnetite mineralization for the Lazhushan deposit by increasing fluid f O 2 and facilitating the oxidation of Fe2+ to precipitate magnetite. LA-ICP-MS U-Pb dating of garnets from 4 garnet-bearing samples yielded ages of 150.8 ± 6.8 Ma (2σ), 150.9 ± 5.3 Ma (2σ), 150.2 ± 7.9 Ma (2σ), and 150 ± 11 Ma (2σ), which are consistent with zircon weighted mean U–Pb ages of 150.1 ± 2.0 Ma (2σ) and 150.5 ± 1.0 Ma (2σ) of the ore-related intrusion. Combined with previously published metallogenetic ages of skarn deposits in the Edong district, we suggest that the Lazhushan deposit may represent the initiation of Fe skarn mineralization for the Edong district during the Late Mesozoic. [ABSTRACT FROM AUTHOR]

[Display omitted] • Latest Oligocene–Miocene arc magmatism in central Oaxaca developed in a thick continental crust. • Early–mid-Miocene metallogenic epoch in southern Mexico comprises Au-Ag rich epithermal deposits. • Precious metal-rich intermediate-sulfidation epithermal deposits occur at Natividad. • Detailed vein stratigraphy reveals multi-episodic fluid pulses and interaction with wall rocks. • First formal report of argyrodite (Ag 8 GeS 6) in Mexico. The final magmatic arc—Miocene in age—of the long-lived Sierra Madre del Sur igneous province in southern Mexico hosts several epithermal deposits that have hitherto received little attention. The Natividad Au-Ag(-Ge) epithermal deposit is one of them and holds a mining record of > 200 years. Here, we present the first petrogenetic and metallogenic study on the Natividad deposit, in which we use a multi-methodological approach to assess the genesis and evolution of the deposit and its associated igneous rocks. Natividad is mostly hosted by Oligocene–Miocene arc-related dacites (U-Pb zircon dates of 22.8–24.7 Ma), whose geochemical features suggest lower-crustal differentiation (i.e., involvement of garnet) at the base of a thickened continental crust. The mineralization occurs in three multi-stage quartz + carbonate veins and consists of Fe-poor sphalerite (<5 mol. % FeS), galena, chalcopyrite, acanthite, and marcasite (sulfide-dominated stage) overprinted by pearceite-polybasite, pyrargyrite-proustite, tetrahedrite-group minerals, electrum, and argyrodite (Ag 8 GeS 6 ; Ag-sulfosalt-dominated stage). Geothermometry and fluid inclusion data for ore-bearing assemblages reveal fluid temperatures of 170°–400 °C and salinities of 14.6–19.5 wt% NaCl equiv. δ18O from 0.8 ‰ to 7.5 ‰ in mineralizing fluids suggests mixtures of magmatic brines and meteoric waters, while δ13C from –8.4 ‰ to 2.2 ‰ indicates the recycling of organic carbon from the meta -sedimentary basement. Further, δ34S from –3.2 ‰ to –0.3 ‰ in sulfides attest to magmatic S. These results align with an intermediate-sulfidation epithermal model, whereby upwelling magmatic ore-bearing brines precipitated the ores due to conductive cooling, dilution, and, locally, boiling. Our study highlights the metallogenic potential of Miocene magmatism in the eastern Sierra Madre de Sur. [ABSTRACT FROM AUTHOR]

[Display omitted] • Four phases of deformation are recorded with the D3 event closely related to gold. • SHRIMP zircon U-Pb dating of granite dikes yields ages of 216 ± 3.0 Ma to 210 ± 9.7 Ma. • Ar-Ar dating of gold-related muscovite gives a mineralization age of 210.9 ± 1.6 Ma. • The Yangshan mineral systems comprise epizonal orogenic gold deposits. The West Qinling Orogen in central China resulted from Late Devonian to Triassic collisional orogenesis involving accreted terranes along the southwestern margin of the North China Block with subsequent ocean closure and collision of the South China Block with those terranes. The Yangshan gold district, with a pre-mining resource of more than 308 t gold, is situated along the Mianlue Suture Zone on the southern margin of the orogen. The gold orebodies are mainly controlled by the ENE-trending Anchanghe-Guanyinba Fault and its subparallel second-order faults. The relatively low pressure–temperature mineralization is dominated by disseminated pyrite, arsenopyrite, and stibnite hosted in phyllite and granite dikes, accompanied by intense muscovite-silica-carbonate alteration. Four major phases of deformation related to collisional tectonics are recorded in the Yangshan gold district. Early N-S-oriented compressional deformation (D1) is characterized by an alignment of muscovite, overgrowths on framboidal pyrite, and quartz veinlets. D2 is characterized by a series of continuous ENE-trending reverse faults and folds at multiple scales related to SSE-NNW-oriented compression. D3 is related to gold mineralization and is characterized by a series of ENE-trending, largely normal faults, formed during transtensional tectonics. D4 post-dates gold mineralization and is associated with the development of nearly N-S-trending, low-displacement normal faults. New high-precision SHRIMP zircon U-Pb dating of three types of granite dikes in the Yangshan gold district yields broadly coincident ages of 216 ± 3.0 Ma to 210 ± 9.7 Ma, which is a range identical to that of existing dates of 217–211 Ma for more regional granite magmatism in this district. New Ar-Ar dating of gold-related muscovite gives an age of 210.9 ± 1.6 Ma for the Yangshan gold deposit, indicating that hydrothermal activity overlapped or post-dated the final stages of granite intrusion. Pre-226 Ma peak metamorphism of the ore-hosting rocks occurred prior to extensional ductile shear deformation that is constrained by a published 40Ar/39Ar muscovite cooling age of 223 ± 2 Ma. In good agreement, U-Pb constrained ages of retrograde metamorphism and associated late magmatism of around 215 Ma are reported for rocks along the Mianlue Suture Zone. These geological and geochronological data suggest that relatively shallow-level gold mineralization was broadly coeval with Late Triassic transtensional, orogen-parallel deformation along the regional-scale fault system, late in the tectonic evolution of the West Qinling Orogen. This is consistent with its classification as epizonal orogenic gold mineralization. [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] • This study is the first attempt of a systematic horizontal skarn profile in Beiya. • Two types of garnet have been distinguished in endoskarn and exoskarn. • The conditions and compositions of hydrothermal fluid in different environments vary. • The skarn mineralization age is restricted by crystallization age of garnet. Garnet is one of the most typical minerals in skarn deposits, and its texture and composition is a proxy for the changing physicochemical conditions. Thus, mineralogical and geochemical characterization of different garnet types can provide important information on the nature and evolution of ore-forming fluids. The Beiya gold-polymetallic deposit is China's largest skarn-type Au deposit with Au reserves of >380 t. Although several studies have addressed the skarn formation mechanism and nature of fluid evolution, a systematic study on the changes in the composition and texture of garnet from wall rocks to ore-related intrusion has not yet been attempted. In this work, we carry out a systematic investigation along a horizonal profile in the open pit of the Beiya deposit. Our results show that the garnet in the profile belongs to grossular-andradite solid solution series with all grains showing well-developed fine oscillatory zoning. The garnets are of two types: the first type (Grt I) formed within the endoskarn, is reddish to red with euhedral-subhedral megacryst structure (>10 mm) and has altered surfaces. The second type (Grt II) occur in the proximal exoskarn, is red to brown–red, euhedral-subhedral, with medium- to fine- grained structure (0.3–4 mm) and displaying oscillatory zoning. Unlike Grt I, hydrous minerals occur in the pores among Grt II garnets, such as calcite, quartz, epidote and chlorite. Also, calcite-chlorite vein, quartz vein and quartz-chalcopyrite-pyrite vein cuts the Grt II garnets. Grt I is dominantly grossular (Adr 14.88-43.58 Grs 55.25-82.87), depleted in the large ion lithophile elements (LILE), relatively enriched in high field strength elements (HFSEs) and enriched in heavy rare earth elements (HREEs) with negative Eu anomalies. Grt II is mostly andradite (Adr 62.18-98.91 Grs 0-36.22), depleted in the LILE and HFSE, enriched in light rare earth elements (LREEs) with slightly positive Eu anomalies. Here we selected Grt II for in-situ LA-ICP-MS U-Pb dating, since Grt I contains negligible uranium. The results yielded a lower intercept 206Pb/238U age of 35.3 ± 1.8 Ma (MSWD = 0.68, n = 23). The calculated oxygen isotopic compositions of hydrothermal fluids in equilibrium with two types of garnets range from 6.46 ‰ to 8.56 ‰ (average 7.89 ‰), which are within the range of values for magmatic fluids. We infer that the physicochemical conditions of the hydrothermal fluid changed from relatively reduced, nearly neutral, and low water/rock ratios to slightly oxidized, slightly acidic, and high water/rock ratios. The chlorine content in the fluid increased during garnet growth. The fluctuating compositions of garnets in the skarn suggest multistage ore-fluid activities and the fluid evolution provide insights into the ore-forming process. [ABSTRACT FROM AUTHOR]

[Display omitted] • A giant porphyry-skarn-epithermal Mo-W-Cu-Zn-Pb-Ag metallogenic system is recognized in the Nannihu ore field. • New geochronological data reveal that the porphyry-related metallogenic system formed in the Early Cretaceous (145–139 Ma). • The episodic magmatism and mineralization resulted in the remarkable enrichment of mineral resources at Nannihu. • The model of this porphyry-related metallogenic system has a significant implication for mineral prospecting in the area. The southern North China Craton owns substantial Mo, W, Zn, Pb, Cu, and Ag resources, and most of them are hosted in hydrothermal deposits that may co-exist in the same ore field. However, the relationship between the different types of deposits is not well-constrained. To better understand this, here we present a comprehensive geological, geochronological, and pyrite geochemical study on the Nannihu ore field in the Luanchuan district. The Nannihu ore field is largely represented by the Nannihu Mo-W deposit, Luotuoshan Zn-Cu-W deposit, and Lengshuibeigou Pb-Zn-Ag deposit. Mo-W mineralization at Nannihu occurs in the contact zone between the Nannihu intrusion and the wall rocks, showing typical characteristics of the porphyry-type deposit. Three paragenetic stages are recognized at Nannihu, including quartz-potassium feldspar stage, quartz-sulfide stage, and quartz-carbonate stage. The Zn-Cu-W orebodies at Luotuoshan are mainly layered or lens-like, occurring within the skarn zones in the Luanchuan Group. Skarn stage, polymetallic sulfide stage, and carbonate stage are revealed at Luotuoshan. Pb-Zn-Ag mineralization at Lengshuibeigou is characterized by banded sulfide veins that are hosted in the NNE-trending fault zone. Three paragenetic stages are developed at Lengshuibeigou: quartz-pyrite stage, quartz-polymetallic sulfide stage, and quartz-carbonate stage. New geochronological data confirm that the Nannihu intrusion was formed by at least two phases of magmatism including the granite porphyry (zircon U-Pb age of 145 ± 2 Ma) and the porphyritic monzogranite (zircon U-Pb ages of 142 ± 1 Ma and 140 ± 1 Ma), which accompanied by two episodes of Mo mineralization at the Nannihu deposit identified by molybdenite Re-Os dating (144.9 ± 0.7 Ma and 142.8 ± 0.6 Ma). The Luotuoshan deposit and Lengshuibeigou deposit formed at 141 ± 1 Ma to 140 ± 1 Ma and 140 ± 3 Ma to 139 ± 3 Ma revealed by U-Pb dating of garnet and monazite, respectively, which are contemporaneous with the late episode of the Nannihu intrusion and Mo mineralization. Pyrite grains of the three deposits have Co/Ni ratios higher than 1, suggesting a unified magmatic-hydrothermal origin for them. Pyrite from Nannihu and Luotuoshan is enriched in Co, Ni, Se, Mo, Mn, and Bi, whereas pyrite from Lengshuibeigou contains high Zn, Pb, As, Cu, Ag, and Au. The regular elemental distribution of pyrite in the Nannihu ore field is consistent with that of typical porphyry-related systems worldwide. Collectively, the Early Cretaceous magmatic rocks and diverse deposits in the Nannihu ore field make up a giant magmatic-hydrothermal Mo-W-Cu-Zn-Pb-Ag metallogenic system, with the porphyry, skarn, and epithermal types of mineralization displaying a zonation from inside to outside. The multi-episode magmatism and mineralization could result in the remarkable enrichment of mineral resources. The close spatial relationship among different types of mineralization in the Nannihu ore field has a significant implication for porphyry-related mineral prospecting in the southern NCC. [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] • Hydrothermal rutile formed in a magmatic-hydrothermal system. • Dashuigou Te-Bi deposit formed at the Oligocene (32.4 ± 3 Ma). • Te-Bi mineralization related to the Eocene-Oligocene alkaline magmatism. The Dashuigou deposit, located in the transitional zone between the Yangtze craton to the east and the Songpan-Ganze orogen to the west, is the world's only known deposit where tellurium and bismuth are exploited as primary products. The Te-Bi orebodies mainly occur as the dolomite-tetradymite and Te-bearing pyrrhotite veins in Triassic low-grade metamorphic rocks. The ore minerals mainly consist of tetradymite, tsumoite, tellurobismuthite, pyrrhotite, and chalcopyrite. While mineralogy and geochemistry of the ores in the Dashuigou deposit have been well documented in the past decades, the age of the Te-Bi mineralization in the Dashuigou district is not well defined due to lack of both suitable dating mineral and chronometer, and thereby impedes further understanding on its ore genesis. Hydrothermal rutile coeval with tetradymite has been identified in this study from a high-grade dolomite-tetradymite vein in the Dashuigou deposit. This rutile is closely associated with tetradymite, tsumoite, Te-bearing pyrrhotite, and contains many tiny tetradymite inclusions. Here, we present the first in situ trace element compositions and U-Pb age of these rutile crystals using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The rutile is enriched in V, Nb, Ta, Sn, and Cr, but has low contents of As, Sb, and W, indicating a magmatic origin. U-Pb dating on rutile demonstrates a well-constrained age of 32.4 ± 3 Ma, which is interpreted as the timing of Te-Bi mineralization for the Dashuigou deposit. This new age provides the first evidence suggesting that the Dashuigou deposit is contemporary with regional Eocene-Oligocene alkaline magmatism and related metallogenic event in Sanjiang region. Compared with the Beiya Te-Bi-bearing porphyry Cu-Au and Yao'an Au deposits in the alkaline magmatic belt, we propose that the Dashuigou Te-Bi deposit was likely product of a concealed alkaline magmatic-hydrothermal system. This study also demonstrates the rutile U-Pb geochronology being a powerful tool for dating unusual ore systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Precise geochronology define the magmatism and mineralization age. • The Late Triassic weakly Mo mineralization and Late Jurassic Ag–Pb–Zn mineralization. • The in situ Sulfur isotope data herein confirm the sulfur was mainly derived from a magmatic source. The large-scale Meng'entaolegai Ag–Pb–Zn polymetallic deposit is located in the Great Hinggan Range metallogenic belt, northeastern China. To better understand the formation of the Meng'entaolegai deposit, we present in situ S isotope data, zircon U–Pb isotope data, sulfide Rb–Sr data, and molybdenite Re–Os data for the units associated with the deposit and surrounding regions. In situ analyses show that the δ34S values of the sulfides (galena, sphalerite, and pyrite) vary from + 2.4‰ to + 6.6‰ (mean = +4.7‰, n = 60). The data herein confirm that the sulfur was mainly derived from a magmatic source. Zircon U–Pb dating of the medium- to coarse-grained monzogranite, plagiogranite, and fine-grained monzogranite from the Duerji batholiths and granodiorite and monzogranite from the Meng'entaolegai deposit yield weighted mean ages of 244.3 ± 1.7, 243.0 ± 2.1, 151.8 ± 1.5, 232.6 ± 2.2, and 223.1 ± 2.3 Ma, respectively. The Meng'entaolegai deposit yields a molybdenite Re–Os age of 229.5 ± 1.5 Ma, but sulfide Rb–Sr dating yields an isochron age of 147.2 ± 2.3 Ma. These new age data have revealed that the Meng'entaolegai polymetallic deposit formed during two mineralization episodes: an early episode at 230 Ma and a second episode at 147 Ma. The Late Triassic hydrothermal activity and weakly Mo mineralization formed in an extensional setting after the final closure of the Palaeo-Asian Ocean. The Late Jurassic hydrothermal activity and Ag–Pb–Zn mineralization formed in an extensional environment related to the Mongol–Okhotsk Ocean, but these exposed granitic rocks are unlikely to be related to the Ag–Pb–Zn mineralization, suggesting that more research is needed on the magmatic hydrothermal activity within the study area. [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 geochronology of apatites can help constrained their origin. • The geochemistry of apatites can be used to indicate magmatic-hydrothermal evolution and tectonic background. • Apatites can record information of ore-forming processes. Apatite is a common accessory phase in magmatic rocks and associated hydrothermal deposits that holds information about the evolution from magma to ore-forming fluid. In this study, we systematically studied the geochronological and geochemical characteristics of apatites hosted in the Fe skarn ores and associated intrusions of syenogranite and monzogranite in the Hutouya polymetallic Fe–Cu–Pb–Zn ore district, Qiman Tagh Metallogenic Belt (QTMB), NW China, in order to gain insight into the metallogenic processes from magmatic crystallization to hydrothermal fluid exsolution. The apatite U–Pb dating results of skarns and related intrusions are 229–228 Ma, and the monzogranite emplacement is slightly later than the syenogranite emplacement and skarn formation. The REE concentrations of the apatites from the skarn-related intrusions are characterized by LREE-enriched patterns and weak negative Eu anomalies. However, the apatites from the skarn ores have high HREE contents, and are characterized by flat chondrite-normalized patterns and strong negative Eu anomalies. These data, combined with variations of element concentrations and ratios in the apatites (eg., Sr, SO 3 , F, Cl, REE, (La/Yb) N , (Sm/Nd) N , (La/Sm) N , (Eu/Eu*) N , (Ce/Ce*) N), record the transition of ore-forming processes from the magmatic crystallization to hydrothermal exsolution, and indicate that the skarn-related magmas with moderately reduced signatures may have been derived from partial melting of crustal materials potentially affected by the limited mantle input under an extensional environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • A four-stage post-Paleozoic cooling history of the Tianyu Cu-Ni ore deposits. • The deformation history of the eastern Central Tianshan during the Mesozoic-Cenozoic. • The post-mineralization exhumation is vital for exposing deep metallogenic systems. The Chinese Eastern Tianshan is an important metallogenic region where major Cu-Ni ores are mined. Previous research in the region primarily focused on the ore genesis. Precise thermochronological data to constrain the exhumation history and preservation of the ore deposits are limited at best. Tianyu is one of these Cu-Ni deposits in the area. Here we present new low-temperature thermochronological data to contribute to the understanding of its exhumation and preservation history. Zircon (U-Th)/He ages of ∼ 134–69 Ma, apatite fission track ages of ∼ 100–75 Ma, and apatite (U-Th)/He ages of ∼ 117–38 Ma from five granodiorite samples of the ore wall rock at different depths of a borehole in the Tianyu deposit were obtained. Our thermochronological data and inverse thermal history modeling reveal a moderate to rapid and final basement cooling phase during the Cretaceous (∼115–85 Ma) with an averaged cooling rate of ∼ 3–4 ℃/Ma. It is envisaged that this phase eventually exposed the ore deposits and that posterior erosion was limited, contributing to the preservation of the deposit. Combined with previously published geochronological and thermochronological data, a multi-stage cooling history of the ore bearing host rocks can be established. After its late Permian (∼280–260 Ma) magmatic-hydrothermal formation, two phases of accelerated regional cooling (i.e., in the late Permian-Early Triassic, ∼260–240 Ma; and the mid-Cretaceous, ∼115–85 Ma) can be recognized. The more intense Cretaceous cooling is associated with the ore body finally being exhumed to the surface, and provides essential information for ore exploration in the region. Further, we propose that areas in the Eastern Tianshan with similar thermal histories to the Tianyu Cu-Ni deposit may be potential exploration targets. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Huanggangliang mineralization may have formed from magmatic-hydrothermal fluids. • U-Pb dating of zircon, cassiterite and garnet provide constraining on the deposit initiations. • The physicochemical conditions of hydrothermal fluids for Huanggangliang deposit cassiterite were constrained. • Cassiterite as a speciation mineral to determine the genesis of tin polymetallic deposits. The Huanggangliang Fe-Sn deposit is located in the southern Da Hinggan Range (NE China), and it's one of the most important deposits within the Huanggangliang-Ganzhuermiao Sn polymetallic metallogenic belt. Nearly 90% of the orebodies (stratiform/lenticular) at Huanggangliang are hosted in the Lower Permian andesite or marble. Three ore deposit types were proposed, including: 1) stratabound skarn-type (Yanshanian); 2) exhalative sedimentary (SEDEX)-type (Hercynian); and 3) SEDEX (Hercynian) - hydrothermal (Yanshanian) superimposing-type. Two generations of cassiterite (Cst-1 and Cst-2) were identified based on their microscopic features and CL images: Cst-1 is dark brown with distinct banded texture (euhedral-subhedral), whilst Cst-2 is light brown in color and cut Cst-1 (as veins) or distributed on the Cst-1 margin. They are both replaced by chlorite and quartz. The Huanggangliang cassiterite has relatively high Fe (median 4828 ppm) and W (median 273 ppm), but low Nb 2 O 5 (<0.08 wt%) and Ta 2 O 5 (<0.09 wt%) contents, distinct from SEDEX-type cassiterite but similar to granite-related cassiterite. Cst-1 has higher Fe-W-U contents than Cst-2, which reflects that Cst-1 was formed under relatively high temperature. Meanwhile, Cst-2 is relatively HFSEs-enriched, suggesting that the metallogenic environment had become more acidic. The cassiterite, zircon and garnet samples were U–Pb dated to be 137.10 ± 3.65 Ma, 138.45 ± 0.45 Ma, and 136.03 ± 1.22 Ma, respectively. Considering the Huanggangliang geology, cassiterite geochemistry and published ages from Sn-polymetallic deposits in the southern Da Hinggan Range, we suggest that the regional Sn mineralization occurred mainly in 139–134 Ma, and that the Huanggangliang deposit is best classified as skarn-type, closely related to Yanshanian magmatic-hydrothermal activity. [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] • Here we characterize the geology and mineralization of the Sangri porphyry-skarn Cu-Mo deposit. • Zircon and garnet U-Pb, molybdenite Re-Os and K-feldspar Ar-Ar geochronology link magmatism, mineralization and alteration. • The Multi-isotopic dating could help to construct the defined time-framework of porphyry system. Obtaining a precise time framework has been a key but difficult problem for the study of metallogenic porphyry systems. This is more complicated when there are several stages of intrusion emplacement, different alterations, and mineralization events. To solve this problem, the Sangri porphyry-skarn Cu-Mo deposit in the Bangongco-Nujiang metallogenic belt, Tibet, was used as a study site for multiple isotopic dating studies. Zircon U-Pb dating of different intrusions shows that the magmatism of intermediate-felsic intrusions dates from 83.2 ± 0.8 Ma to 81.7 ± 0.7 Ma. Garnet U-Pb dating places the skarn as being formed in 83.2 ± 2.3 Ma. Re-Os dating of molybdenite in quartz-molybdenite vein and Ar-Ar dating of K-feldspar indicate ore-forming and alteration periods of 82.6 ± 0.6 Ma and 80.3 ± 1.8 Ma, respectively. The Sangri deposit is a product of magmatic-hydrothermal mineralization between 84 and 80 Ma in the Late Cretaceous. The mineralization of the Sangri deposit and precise geochronology data indicate that there was a Late Cretaceous metallogenic event in the Central Bangongco-Nujiang metallogenic belt, which provides a new clue for regional exploration and metallogeny. Finally, multi-element isotopic dating is shown to be an important method for constructing the time framework of porphyry systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ages of W ores by wolframite U-Pb dating in Jinzhuping, Changkeng, Keshuling, Taoxikeng and Bikeng deposits, southern Jiangxi, are 154.2 ± 4.1 Ma, 157.8 ± 9.4 Ma, 150.3 ± 1.8 Ma, 153.8 ± 4.0 Ma and 152.3 ± 5.6 Ma, respectively. • Three stages of W mineralization occurred from the Triassic to the Lower Cretaceous in the Nanling Range of South China. In situ LA-ICP-MS provide high-resolution spatial analysis of wolframite grains. In this paper, wolframite U-Pb isotope dating is presented to directly constrain the timing of W mineralization in five granite-related vein-type W-polymetallic deposits from different ore-concentrated areas in southern Jiangxi Province, South China. In the Jinzhuping, Changkeng, Keshuling, Taoxikeng, and Bikeng deposits, wolframite is the dominant ore mineral, occurring as coarse, euhedral grains that are associated with gangue minerals such as cassiterite, scheelite, molybdenite, sphalerite, (±) galena, (±) marmatite, pyrite, quartz, (±) chlorite, (±) fluorite, and calcite. Wolframite U-Pb dating yielded 206Pb/238U ages of 154.2 ± 4.1 Ma for the Jinzhuping deposit, 157.8 ± 9.4 Ma for the Changkeng deposit, 150.3 ± 1.8 Ma for the Keshuling deposit, 153.8 ± 4.0 Ma for the Taoxikeng deposit, and 152.3 ± 5.6 Ma for the Bikeng deposit, respectively. By comparing the published minerlizing ages of the W-Sn polymetallic deposits in the Nanling region, we suggest that three stages of W mineralization occurred from the Triassic to the Lower Cretaceous. [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]

[Display omitted] • Late Cretaceous-Paleogene thermochronological signals revealed in the East Qinling Orogen. • Two rapid cooling (125–100; 73–50 Ma) and one slow cooling stages in between are identified. • More than 1 km metallogenic depth preserved for mineral exploration in the Yumugou deposit. As a result of the continued depletion of shallow ore resources, there has been renewed focus on the tectonic preservation of mineralized systems. Specifically, it is vital to constrain the post-mineralization exhumation and preservation history of existing economic deposits, in order to identify new regions suitable for mineral exploration. In this study, we present results from apatite U-Pb, fission-track and (U-Th-Sm)/He thermochronological and associated thermal history modeling studies on the Yumugou Mo-W deposit within the world-class East Qinling Mo polymetallic metallogenic belt, central China. Our major aim is to constrain the exhumation history and to evaluate preservation potential of the Yumugou Mo-W deposit, and provide related guidance for mineral exploration in the East Qinling Orogen. Apatite U-Pb dating yield Early Cretaceous lower intercept Terra-Wasserburg ages in the range of 153–141 Ma, interpreted as crystallization age of apatite, coeval with the formation of Yumugou deposit (ca. 145 Ma). Integrated apatite fission-track and apatite (U-Th-Sm)/He dating give ages varying from Late Cretaceous to Early Paleogene, representing the post-mineralization cooling ages. We also integrate these age data with confined fission-track length measurements and geological constraints from previous studies into the thermal history models, the resulting models suggest three cooling pulses: 1) a phase of Early Cretaceous (125–100 Ma) rapid cooling, followed by 2) a phase of Late Cretaceous (100–73 Ma) slow cooling, before finally, 3) a phase of Late Cretaceous to Paleogene (73–50 Ma) rapid cooling. The Early Cretaceous rapid cooling pulse correlates temporally with extension tectonic setting in the East Qinling Orogen, the magma emplacement and post-magmatic rapid cooling at ca. 160–130 Ma in the Luanchuan region might cause related exhumation at ca. 125–100 Ma to upper crustal temperatures. The Late Cretaceous slow cooling possibly corresponds to regionally slow extensive erosion in response to crustal shortening triggered by the westward subduction of the Paleo-Pacific Plate at this time. The Late Cretaceous-Paleogene rapid cooling likely result from the major far-field effects of the Pacific Plate subduction and the sinistral strike-slip motion of the Tan-Lu Fault Zone, as well as possible minor expansion effects derived by the Paleogene India-Eurasia collision. Moreover, we adopt thermal history modeling method to determine cooling rate, exhumation rate and depth of different cooling stages. In comparison with the calculated exhumation depth (∼5.6 km) and previously reported metallogenic depth (3–7 km) in the Luanchuan ore cluster, we infer that more than one kilometer metallogenic depth is theoretically preserved in the Yumugou Mo-W deposit. Combined the similar metallogenic setting and features with other giant Mo deposits in the East Qinling Orogen, we further suggest that the Mo deposits in this orogen possibly have underwent a similar degree of exhumation and show good prospecting potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • Summaries of Mesozoic intrusions and related Cu-Au deposits in Tongling, eastern China. • Tongling region experienced two stages of magmatic activities corresponding to compressional and extensional settings. • Two stages of magmatism and mineralization are closely related to the subduction of the Paleo-Pacific plate. • Ore-forming fluids mainly come from magma and are mixed with a small amount of meteoric water. The Tongling ore-cluster region is one of the most important Cu-Au polymetallic producers in the famous Lower Yangtze River Metallogenic Belt (LYRMB) in eastern China. The Cu-Au polymetallic ore deposits can be divided into four types, i.e., skarn, strata-bound hydrothermal, porphyry, and cryptobreccia, closely related to the Late Jurassic to Early Cretaceous magmatism. We summarize the geology of the Mesozoic Cu-Au deposits in Tongling, eastern China, and revisit the age distributions and geochemical characteristics of associated Mesozoic intrusions, by integrating a large number of published geochemical data (including major and trace elements for both early-stage and late-stage intrusions, whole-rock Sr-Nd-Pb isotopes, and zircon U-Pb age and Hf isotopes for early-stage intrusions), to reveal their sources and genesis. According to the U-Pb ages of intrusions, the main magmatic events in the area can be divided into two stages, i.e., 152–135 Ma and 135–124 Ma, respectively. The early-stage magmatism mainly produced Cu-Au mineralization-related dioritic intrusions, including pyroxene diorite-pyroxene monzodiorite, quartz diorite-quartz monzodiorite, and granodiorite, showing unobvious geochronological order. Geochemical data of Late Jurassic-Early Cretaceous intrusions from the early-stage magmatism suggest that they are all derived from a similar source composed of different proportions of slab-derived melt, metasomatized lithospheric mantle, and a lesser content of lower crust materials. Among them, the key differences lie in that more lower crust materials are incorporated in the source of intermediate-felsic rocks compared to intermediate-basic rocks. The late-stage magmatism produced a wide variety of rocks (diorite porphyry, syenite porphyry, granite porphyry, monzonite, and granite porphyry), which are related to Pb-Zn deposits. The late-stage igneous rocks may evolve from the early-stage rocks and have experienced fractional crystallization of apatite, ilmenite, and other minerals. Both early and late-stage magmatic events in the Tongling region were formed in the subduction setting, and corresponding to compression and extensional setting, respectively. Besides, the H-O isotopes of different kinds of minerals suggest that the ore-forming fluids of most ore deposits were mainly derived from the magma and mixed with a small amount of meteoric water in the late-stage mineralization. The S isotopes of sulfides show that the ore-forming materials come from the magma, accompanied by the addition of original sediments. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal titanite in Kaladawan yielded an U-Pb age of 482.6 ± 4.4 Ma. • Garnet in Kaladawan yielded an U-Pb age of 481.0 ± 3.9 Ma. • The deposits in Kaladawan are skarn-type. The Kaladawan Fe–Mo orefield is located in the east of the Altyn Mountains, NW China. It contains six Fe(–Mo) deposits, with total reserves of 60 Mt Fe and 10 kt Mo by-product. Mineralization is hosted in the contact zone between Early Paleozoic volcanic–sedimentary rocks and Ordovician granite, with intense and pervasive skarn alteration. Skarns exhibit some stratabound features. These deposits were variably classified as sedimentary-type with hydrothermal overprints, submarine volcanogenic iron-oxide- (SVIO-) type or skarn-type, centered on whether they are syngenetic or epigenetic. Titanite and garnet from skarn in the ore field are newly U–Pb dated to be ca. 482.6–481.0 Ma, consistent with the intrusive age of the granite but later than the formation age of the host rocks. These age data also further support that mineralization in the Kaladawan orefield is skarn-type. [ABSTRACT FROM AUTHOR]