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The mineral zircon has a robust crystal structure, preserving a wealth of geological information through deep time. Traditionally, trace elements in magmatic and hydrothermal zircon have been employed to distinguish between different primary igneous or metallogenic growth fluids. However, classical approaches based on mineral geochemistry are not only time consuming but often ambiguous due to apparent compositional overlap for different growth environments. Here, we report a compilation of 11 004 zircon trace element measurements from 280 published articles, 7173 from crystals in igneous rocks, and 3831 from ore deposits. Geochemical variables include Hf, Th, U, Y, Ti, Nb, Ta, and the REEs. Igneous rock types include kimberlite, carbonatite, gabbro, basalt, andesite, diorite, granodiorite, dacite, granite, rhyolite, and pegmatite. Ore types include porphyry Cu-Au-Mo, skarntype polymetallic, intrusion-related Au, skarn-type Fe-Cu, and Nb-Ta deposits. We develop Decision Tree, XGBoost, and Random Forest algorithms with this zircon geochemical information to predict lithology or deposit type. The F1-score indicates that the Random Forest algorithm has the best predictive performance for the classification of both lithology and deposit type. The eight most important zircon elements from the igneous rock (Hf, Nb, Ta, Th, U, Eu, Ti, Lu) and ore deposit (Y, Eu, Hf, U, Ce, Ti, Th, Lu) classification models, yielded reliable F1-scores of 0.919 and 0.891, respectively. We present a web page portal (http://60.205.170.161:8001/) for the classifier and employ it to a case study of Archean igneous rocks in Western Australia and ore deposits in Southwest China. The machine learning classifier successfully determines the known primary lithology of the samples, demonstrating significant promise as a classification tool where host rock and ore deposit types are unknown. [ABSTRACT FROM AUTHOR]

The Jiawula Ag–Pb–Zn deposit is located in the northern part of the Great Xing'an Range metallogenic belt within the eastern segment of the Central Asian Orogenic Belt. Here, we report results from muscovite 40Ar/39Ar geochronology and fluid inclusion study and formulate a vertical projection map of the ore grade in this deposit. The muscovite from the Jiawula deposit yields a plateau age of 133.27 ± 0.66 Ma and a 40Ar/39Ar isochron age of 131.88 ± 0.83 Ma. The muscovite 40Ar/39Ar data indicate a discrete second hydrothermal event postdating the mineralization, which we correlate with post‐collisional extension after the subduction direction of the Palaeo‐Pacific Plate changed. Low‐salinity aqueous fluid inclusions in quartz from the Jiawula deposit represent meteoric water or groundwater. Based on the fluid inclusion study, the fluids were trapped during cooling and decompression, which may have resulted in metal precipitation. We envisage that the copper precipitated from a high‐temperature fluid in the southern domain whereas lead, zinc, and silver precipitated at a lower temperature in the north. The spatial distribution of the ore‐forming elements, therefore, reflects the ore fluid migration‐cooling path from the south to north. [ABSTRACT FROM AUTHOR]

Mesozoic magmatism and lithospheric destruction in East China exerted significant control on gold metallogeny. Here, we investigate the mineralogy, geochemistry, geochronology, and isotopic systematics of the Dongyang gold deposit in southeast China to constrain its origin and geodynamics. This is a newly discovered epithermal gold deposit along the Circum–Pacific metallogenic belt and is characterized by intense silicification and sericitization. The C–H–O isotope data suggest deep magmatic sources of the ores and indicate that the ore‐forming fluids comprised a mixture of magmatic water and meteoric water. The S–Pb values of the pyrite indicate magmatic origin for the sulfur, and deposit was derived mostly from crustal sources, mixed with mantle materials. The Rb–Sr dating of the pyrite from the ore deposit shows an age of 164.2 ± 9.9 Ma, whereas the zircon U–Pb SHRIMP ages of the rhyolite porphyry is 160.9 ± 0.5 Ma, suggesting that the timing of mineralization is close to that of the crystallization of the dykes. In conjunction with previous studies on similar deposits, we suggest that the gold mineralization was the response of continental lithospheric thinning in southeast China triggered by the subduction of the Palaeo‐Pacific Ocean Plate. [ABSTRACT FROM AUTHOR]

The North China Craton (NCC) is a window to decratonization and associated gold metallogenesis during the Mesozoic. Although Early Cretaceous gold mineralization associated with craton destruction has been reported, information on decratonic gold metallogenesis during the other periods remain scarce. Here we investigate the Guilaizhuang crypto-explosive breccia-type Te-Au deposit from eastern NCC and present Rb-Sr geochronological data on pyrite which provide new constraints on the timing of mineralization as 180.8 ± 2.3 Ma, corresponding to Jurassic gold metallogenesis. The S-Pb-C-O isotopic systematics and the ( 87 Sr/ 86 Sr) i value of the pyrite as ca. 0.712429 ± 0.000076 suggest that the ore-forming nutrients were derived from crustal and mantle sources. The Guilaizhuang Te-Au deposit formed during the tectonic transformation from compression to extension associated with the extensional collapse of the Dabie–Sulu UHP orogen and the delamination of the NCC lithosphere, triggering mantle upwelling and extensive crustal melting. [ABSTRACT FROM AUTHOR]

The Niujuan breccia-type silver deposit forms part of the North Hebei metallogenic belt along the northern margin of the North China Craton. The Hercynian Baiyingou coarse-grained granite and the Yanshanian Er’daogou fine-grained granite are the major Mesozoic intrusions exposed in this region. Here we investigate the salient characteristics of the mineralization and evaluate its genesis through zircon U-Pb and fluorite Sm-Nd age data, and Pb, S, O, H, He and Ar isotope data. The orebodies of the Niujuan silver deposit are hosted in breccias, which contain angular fragments of the Baiyingou and Er’daogou granitoids. The δ 34 S values of pyrite from the silver mineralized veins range from 2.4‰ to 5.3‰. The 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios of the sulfide minerals show ranges of 16.837–16.932, 15.420–15.501 and 37.599–37.950, respectively. The 3 He/ 4 He and 40 Ar/ 36 Ar ratios of the fluids trapped in pyrite are 0.921–4.81Ra and 299.34–303.84, respectively. The δ 18 O and δ 18 D w values of the ore-forming fluids range from 0.6‰ to −4.15‰ and from −119.4‰ to −98.7‰, respectively. Our isotopic data suggest that the ore-forming fluids were originally derived from the subvolcanic plutons and evolved into a mixture of magmatic and meteoric water during the main hydrothermal stage. The ore-forming materials were primarily derived from the lower crust with limited incorporation of mantle materials. The emplacement time of the Er’daogou granite is constrained by LA-ICP-MS zircon U-Pb geochronology at 145.5 ± 2.1 Ma. Five fluorite samples from the last hydrothermal stage yielded a Sm-Nd isochron age of 139.2 ± 3.8 Ma, indicating the upper age limit for the silver mineralization. These ages correlate with the formation of the Niujuan deposit in an extensional setting associated with the closure of the Mongol-Okhotsk Ocean and the subduction of the Paleo-Pacific oceanic plate beneath the North China Craton. [ABSTRACT FROM AUTHOR]

The Yixingzhai and Xinzhuang gold deposits are the most important gold mineralization of the Wutai-Hengshan region in the center of the North China Craton (NCC). Here we present new geological, mineralogical, geochemical and geochronological evidence from these deposits with a view to formulate a comprehensive model for the Mesozoic magmatism and metallogeny in the NCC. Our Re-Os dating of molybdenite from the Hewan granite porphyry constrains the timing of mineralization as 142 Ma. Gold mineralization occurred in the late stage of magmatism with close temporal and spatial relationships with the Sunzhuang pluton. Intensive parameters using amphibole, biotite, magnetite-ilmenite mineral thermobarometry and oxygen fugacity indicate that the parental magma for the Sunzhuang pluton evolved at high oxygen fugacity (>NNO + 2 buffer), and was emplaced at a depth of 2–2.6 km. The He-Ar isotopic composition of the fluid inclusions from pyrite grains in the Yixingzhai gold deposit suggests the involvement of mantle-derived fluids although the Pb isotope data shows that ancient lower crust is the major source. The major and trace element features, Sr-Nd-Pb and zircon Hf isotope data coupled with available geophysical information suggest that magmatism and mineralization in this region witnessed the interaction of mantle-derived mafic magmas with lower crust, with the latter as the major source. The magmatic and metallogenic processes involved the following: (1) partial melting and production of mafic magma triggered by upwelling asthenosphere; (2) mafic magma underplating under lower crust and partial melting of the ancient lower crust generated granitic magma; (3) formation of intermediate magma through the interaction between mafic and felsic magmas; (4) separation of ore-forming fluids from the Sunzhuang pluton and their migration through fault zones in the shallow crust generating the gold mineralization. [ABSTRACT FROM AUTHOR]

The Karakoram Block in North Pakistan formed during the late Permian-Triassic on the southern margin of Asian Plate with a topography characterized by glaciated high mountains. Several rivers and streams draining from these mountain peaks carry detritus with precious and base metals. However, the primary source deposits and their ore genesis remain unknown due to the rugged glaciated topography and inaccessibility for prospecting and in situ sampling. Here, we present a multi-parametric analytical approach including major and trace element characteristics, thermoelectric analysis, EPMA elemental mapping, XRD analysis, and sulfur and lead isotopic studies on the detrital auriferous pyrite from Shimshal Valley placer gold deposits in the Karakoram Block of the north Pakistan to gain insights into the ore genesis, provenance and current erosion or denudation rate of the source primary deposits found in the hinterlands of the Shimshal Valley. The pyrite with varying forms such as {100} + {111} + {210} followed by {210} + {111} and {100} + {210}, which are highly enriched in gold (up to 1700 ppm) as revealed through EPMA analysis. The low to moderate temperature estimated for their formation (100 to 360 °C), pyrite geochemical characteristics, geochemical discrimination diagrams (Fe/S-As, Fe + S-As, As-Co-Ni) and elements contents (Au, Ag, Cu) of the placer gold grains, as well as the high (58.2 %) and low (41.8 %) thermoelectric coefficients of N-type and P-type, suggest that the auriferous pyrite belong to the epithermal type of magmatic-hydrothermal systems. The XnP value (average −48.7 %), γ value (average 62.8 %) in conjunction with the n(S)/n(Fe) values of 1.97–2.11 of pyrite indicate that the placer gold deposits are derived from the middle-upper part of the ore body. The high Mo/Ni (average 5.4) and Co/Ni (average 2.7) ratio combined with detrital zircon U Pb geochronology, zircon fertility indicators such as Eu/Eu*, Ce/Nd, (Ce/Nd)/Y, Dy/Yb, (Eu/Eu*)/Y, texture and REE patterns correlate the ore mineralization with the Hunza Plutonic Unit emplaced on the catchment of the valley. The narrow variations in δ34S values, ranging from −5.3 to 3.8 ‰ with an average of −4.7 ‰, suggest that sulfur has a homogeneous magmatic source. The Pb isotopes values range 18.487 to 18.692, 15.713 to 15.745, and 38.964 to 39.416 for 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb, respectively. Our results suggest that metals for ore-forming fluid involved considerable contribution of crustal-derived materials. [Display omitted] • The studied placer gold deposits are sourced from epithermal type of deposits. • Proximal source with probable mineralization beneath the current level of erosion • Gold is found in pyrite as micro to nano inclusions as Au0 instead of Au+1. • Source deposits are associated with 109 MA plutons of Hunza Plutonic Unit. • Orogenic belts and crustal derived ore forming fluids are suggested. [ABSTRACT FROM AUTHOR]

The Han-Xing region is located in the south Taihang Mountains (TM) in the central part of the North China Craton, and is an important iron producing area. The iron deposits in this region are of skarn type, related to an Early Cretaceous high-Mg diorite complex, including gabbro diorite, hornblende diorite, diorite, diorite porphyrite, and monzonite. In this study we report the detailed mineral chemistry of the high-Mg diorites and skarn rocks. The olivine in the gabbro diorite shows chemical composition similar to that in mantle peridotite xenoliths. Clinopyroxene in the gabbro diorite is dominantly augite, with only minor diopside, whereas the clinopyroxenes in the diorite and monzonite are diopside. Amphiboles in the high-Mg diorites show compositional range from magnesiohornblende to magnesiohastingsite, with minor pargasite and tschermakite. Most plagioclase in the high-Mg diorite is andesine and oligoclase. The magnesio-biotite in gabbro diorites shows chemical characteristics of re-equilibrated primary biotites and those in calc-alkaline rocks. In the diorite and diorite porphyrite, plagioclase shows complex chemical zoning. Clinopyroxene and garnet in skarn rocks show varying FeO contents, the former containing low FeO (< 9 wt.%) and occurring as the major skarn mineral in large-scale iron deposits, and the latter within small-scale iron deposits with high FeO (mostly > 25 wt.%) content. We computed the pressure, temperature, oxygen fugacity and water contents based on the mineral chemistry of amphibole and biotite. Based on the results, the magma crystallization can be divided into two stages, one within the deep magma chamber, forming clinopyroxene, amphibole and plagioclase phenocrysts; the other after emplacement, forming the rim of phenocrysts and matrix minerals. The magma during the early stage shows high temperature (~ 900 °C–950 °C), pressure (~ 300 MPa–500 MPa), relatively high logfO 2 (NNO–NNO + 2), and H 2 O content in melt (4%–8%). During the late stage, the magma temperature dropped to about 750 °C, and pressure came down to less than 100 MPa, with the logfO 2 rising to NNO + 1–NNO + 2. The zoning of amphibole and plagioclase records the process of magma mixing and crystallization, with injection of mafic magma into the felsic magma chamber. The relatively high logfO 2 and H 2 O content inhibited partitioning of iron into mafic minerals and favored concentration of Fe in the melt. Iron ore precipitation occurred when the magma was emplaced at shallow level, and was principally controlled by the chemical composition of carbonate wall rocks. The high logfO 2 , Fe 3 + rich ore-forming fluid generated andradite and clinopyroxene when it reacted with limestone and dolomitic limestone respectively. [ABSTRACT FROM AUTHOR]

The Yinan gold deposit in the Luxi area of Shandong Province in northeastern China is a skarn-type ore deposit. In this article, we present results from sulphur, lead, carbon–oxygen, and helium–argon isotope chemistry to characterize the ore genesis and source features. We also present rhenium–osmium ages from molybdenite to evaluate the timing of ore formation. The δ34S values of pyrite from the ore deposit range from 0.7‰ to 5.60‰ with a mean at 2.70‰, close to mantle and meteorite sulphur. Among Pb isotopes,206Pb/204Pb values range from 18.375 to 18.436,207Pb/204Pb values from 15.694 to 15.8, and208Pb/204Pb values from 38.747 to 39.067. The δ13C values of calcite associated with the ores range from −0.2‰ to −0.5‰ and their δ18O values show variation from 9.4‰ to 12.6‰, suggesting a mixed fluid source. The3He/4He and40Ar/36Ar ratios of fluids trapped in pyrite are in the range of 0.27–1.11 Ra and 439.4–826, respectively, with calculated proportion of the mantle-derived He ranging from 3.25% to 14.03% and atmosphere argon ranging from 35.8% to 67.3%. The data suggest that the ore-forming fluids were derived from the crust and were mixed with a distinct contribution of mantle helium. The Re and Os values vary from 32 × 10−6to 93.02 × 10−6and from 0.01 × 10−9to 0.34 × 10−9, respectively. The model ages of molybdenite range from 126.96 ± 1.82 Ma to 129.49 ± 2.04 Ma, with a weighted mean age of 128.08 ± 0.75 Ma and isochron age of 130.3 ± 3 Ma. These ages are close to the age of the associated quartz diorite porphyrite pluton, suggesting a close relationship between Cretaceous magmatism and metallogeny in NE China. A comparison of the Yinan gold deposit in the Luxi area with those of the Jiaodong area shows that the contrast in metallogenic features between the two are linked with the tectonic and geodynamic history. [ABSTRACT FROM AUTHOR]

Abstract: The link between metallogeny and craton destruction in the North China Craton (NCC) remains poorly understood, particularly the mechanisms within the interior of the craton. In this overview, we summarize the major stages in the history of formation and evolution of the NCC, the spatio-temporal distribution and types of major ore species, as well as mantle contribution to the metallogeny, in an attempt to evaluate the geodynamic settings of metallogeny and the mechanisms of formation of the ore deposits. The early Precambrian history of the NCC witnessed the amalgamation of micro-blocks and construction of the fundamental tectonic architecture of the craton by 2.5Ga. The boundaries of these micro-blocks and the margins of the NCC remained as weak zones and were the principal locales along which inhomogeneous destruction of the craton occurred during later tectonothermal events. These zones record the formation of orogeny related gold, copper, iron and titanium during the early to middle Paleoproterozoic with ages ranging from 2.5 to 1.8Ma. The Early Ordovician kimberlite and diamond mineralization at ca. 480Ma, the Late Carboniferous and Early to middle Permian calc-alkaline, I-type granitoids and gold deposits of 324–300Ma, and the Triassic alkaline rocks and gold–silver-polymetallic deposits occurring along these zones and the margins of the blocks correlate with rising mantle plume, southward subduction of the Siberian plate and northward subduction of the Yangtze plate, respectively. The voluminous Jurassic granitoids and Cretaceous intrusives carrying gold, molybdenum, copper, lead and zinc deposits are also localized along the weak zones and block margins. The concentration of most of these deposits in the eastern part of the NCC invokes correlation with lithosphere thinning associated with the westward subduction of the Pacific plate. Although magmatism and mineralization have been recorded along the margins and few places within the interior of the NCC in the Jurassic, their peak occurred in the Cretaceous in the eastern part of the NCC, marking large scale destruction of the craton at this time. The junctions of the boundaries between the micro-continental blocks are characterized by extensive inhomogeneous thinning. We propose that these junctions are probably for future mineral exploration targeting in the NCC. [Copyright &y& Elsevier]

• Porphyry and epithermal type of gold deposits in the hinterlands of the Bagrote valley. • Proximal source and high content of gold in pyrite suggest probable mineralization beneath the current level of erosion. • Gold occurs in pyrite in the form of micro to nano inclusions as Au0 instead of Au+1. • Ore forming fluids were derived from orogenic belts with minor contribution of lower crust. The Bagrote valley in North Pakistan, belonging to the Kohistan island arc, is well-known for regional placer gold mining. However, no economically feasible in situ hydrothermal gold deposits have been discovered in this region due to rugged terrain and remote nature of its location in the western Himalaya. The streams draining the Main Karakoram Thrust (MKT)/Shyoke suture zone carry placer gold in sediments as well as old river terraces, although the primary source remains unknown. In this paper, we employ a multiparametric approach including, X-ray Diffraction (XRD) analysis, thermoelectricity, major and trace element geochemistry and isotopic characteristics of pyrite associated with placer gold with a view to identify the nature of the unknown deposits and ore forming fluids on the catchment of the Bagrote valley. Pyrite in the Bagrote valley placers is euhedral to subhedral indicating the proximal gold sources. The high rate of occurrence of N-type thermoelectric coefficients (89%) with low P-type (11%) and crystallization temperature (290 °C−380 °C) combined with chemical features indicate that the pyrite was derived from porphyry or epithermal type of magmatic hydrothermal gold deposits from the hinterlands of the Bagrote valley. The X-Ray elemental maps show that Fe, As, Mo and Ni are homogenously distributed from core to rim suggesting stable crystallization condition without any alteration by later fluids. The calculated chemical formula of pyrite of our samples is [Au0.0006Fe] S2.004], plots of Au-As and Au-Fe shows that gold occurs in pyrite as micro to nano inclusion as Au0. The δ 34 S V - CDT values of pyrite range from – 0.6‰ to 0.9‰ with an average of −0.02‰, indicating the derivation of sulfur from a homogeneous magmatic source. The Pb isotope data indicates that the Pb was sourced from orogenic-type source, with minor contribution of lower crust. The narrow variations in 206Pb/204Pb and 208Pb/204Pb values suggest a single lead source. The low, medium and high Mo/Ni ratios reflect a mixed provenance for the auriferous pyrite. The average value of γ (71.8%), of pyrite computed from thermoelectric parameters (XnP), suggests that the dominant part of the primary source that contributes to the placers might have already been eroded. However, the proximal source and with high content of gold in the pyrite grains (up to 1160 ppm) suggest the possibility of significant economic mineralisation below the present erosion level of the deposits in the hinterlands of Bagrote Valley. [ABSTRACT FROM AUTHOR]

• Pyrite Rb-Sr data constrain the timing of gold mineralization as Early Cretaceous. • Zircon U-Pb ages from the clasts do not correspond to the gold metallogeny. • Gold mineralization in extensional setting associated with craton destruction the NCC. The Puziwan gold deposit, located in north-western Shanxi province in North China, is a typical cryptoexplosive breccia-related gold deposit. Here we present new zircon U-Pb and pyrite Rb-Sr geochronology, and zircon Lu-Hf and pyrite S-Pb isotopic data to constrain the timing of ore formation and to gain insights into the source of the metal and genesis of the deposit. The clasts of the ore bodies of the deposit consist mainly of quartz porphyry and granulite. Pyrite and the oxidized limonite account for ∼70% of the total ore minerals associated with the entire ore-forming process. Gold is dominated by electrum and native gold which mainly occur in the interstices and fissures of pyrite. We identify six stages during the mineralization process: (1) gold-bearing quartz-pyrite, (2) quartz-pyrite-sericite, (3) quartz-sericite-Au-Ag polymetallic sulfides, (4) quartz-Ag polymetallic sulfides, (5) gold-bearing sulfide-quartz, and (6) carbonate-pyrite. The pyrite from the main mineralization stage yields Rb-Sr isochron age of 139.2 ± 1.1 Ma, suggesting that the Puziwan gold deposit formed during the Early Cretaceous, much later than the Triassic emplacement of the quartz porphyry (∼229 Ma). The S, Pb and Sr isotopic data suggest that the source of the ore is closely related to deep-seated magmatism derived through mixing of lower crust and mantle material. The geochronological and isotopic data preclude the associated Triassic quartz porphyry as the source, and suggest probable hidden deep-seated Cretaceous magmatism, forming an intrusion related auriferous system. The brecciation resulted from the cryptoexplosion and fluidization. Synchronously, or slightly after the brecciation, the ore fluids were channeled along the breccias and fractures or faults within the fracture zone. Occurrence of other gold deposits in the North China Craton which share similar geochronological and isotopic characteristics with Puziwan gold deposit indicates that these cryptoexplosive breccia-related gold deposits formed during lithospheric extension associated with craton destruction triggered by the subduction of Paleo-Pacific Plate during the Late Jurassic to Early Cretaceous. [ABSTRACT FROM AUTHOR]

[Display omitted] • Erdaokan is a magmatic-hydrothermal deposit genetically linked with bitumen. • Bitumen is of biogenic origin, and was sourced from the adjacent sedimentary strata. • Organic matter that formed bitumen significantly interacted with ore-forming fluids. The newly discovered Triassic Erdaokan Ag-Pb-Zn deposit having an ore reserve of 2964 kt, with an average grade of 517 g/t Ag, 0.6 wt% Pb and 0.4 wt% Zn, is the only known bitumen-bearing magmatic-hydrothermal Ag-Pb-Zn deposit in the northeastern segment of the Great Xing'an Range, NE China. Its genetic relationship with organic matter remains elusive. In this contribution, we present results from detailed geochemistry, isotope and biomarker studies on bitumen and discuss the genesis of bitumen and its relationship with Ag-Pb-Zn mineralization. The carbon isotope and biomarker analyses suggest a biogenic origin for the organic matter that formed bitumen. We infer that the organic matter was most likely sourced from the carbonaceous shale and limestone belonging to Niqiuhe Formation. Significant interaction between the organic matter and ore-forming fluid is indicated. The light n-alkanes and analogs, alkali elements, vanadium and nickel in the bitumen were removed by the ore-forming fluid, and a variety of metal elements entered into the bitumen. The thermochemical oxidation of methane induced by high-valence metal oxides and thermochemical sulfate reductions were the two main interaction mechanisms between the organic matter and ore-forming fluid, which made an effective contribution to metal precipitation in the Erdaokan Ag-Pb-Zn deposit. On this basis, we propose a genetic model for the genesis of the Erdaokan Ag-Pb-Zn deposit and other hydrocarbon-bearing magmatic-hydrothermal deposits which envisages a significant role played by the organic matter sourced from the sedimentary rocks in ore concentration. [ABSTRACT FROM AUTHOR]