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[Display omitted] • Gangjiang porphyry Cu–Mo mineralization is associated with adakitic intrusions. • Copper-Mo orebodies are hosted in the potassic and phyllic alteration zones. • Intrusions were derived from the mixture of crust and metasomatized juvenile mantle. • The mantle components increased from the west section to the east section of the Gangdese. The Gangjiang Cu–Mo deposit is located in the central Gangdese porphyry Cu belt (GPCB), south Tibet. Geological investigation reveals that the Gangjiang deposit is characterized by early potassic alteration, followed by late phyllic and argillic alteration. Late alteration has different degrees of overprinting over the potassic alteration zone. Copper-Mo orebodies are predominantly hosted in the potassic and phyllic alteration zones of the Miocene monzogranite porphyry (MGP) and granodiorite porphyry (GDP). In this study, we present the chemistry and Sr–Nd–Pb–Hf–O isotope compositions of fertile MGP and GDP, barren tonalite porphyrite (TP), and microgranular mafic enclaves (MMEs). Chemical compositions indicate that these intrusions are I-type granites that show high–K calc-alkaline signatures. The negative correlation between Dy/Yb and SiO 2 indicates that the intrusions experienced fractionation of amphibole. They have high Sr/Y (>70) and La/Yb (>38) ratios, strong negative Nb–Ta–Ti anomalies, and positive Pb anomalies are typical for arc magma. The high Mg# of various porphyry intrusions (43–65) and MMEs (47–58) indicate the input of mafic components. Various intrusions have whole-rock 87Sr/86Sr (t=13Ma) ratios of 0.70529 to 0.70674, negative εNd (t=13Ma) (−5.0 to −1.2), positive zircon εHf(t) (1.2–9.8), and homogeneous δ18O (5.8–7.1 ‰, mean 6.6 ‰). The MMEs have similar Sr–Nd–Pb–Hf–O isotopic compositions with their host rocks. The features reveal that the Gangjiang adakite-like intrusions and MME samples were derived from the partial melting of the Lhasa Paleoproterozoic crust, with contributions from the juvenile mantle that has been metasomatized by subducted sediments-derived melts. Note, the MGP, GDP, and two types of MMEs have slightly lower δ18O values (down to 4.76 ‰) but higher εNd (t) (up to −1.2) than barren TP, indicating their formation involves more mantle components. Furthermore, the MMEs in the TP and MGP have high Cu contents (up to 1485 ppm), similar to the phenomenon occurs in the Qulong deposit. The Cu-rich MME is probably formed by Cu-refertilization by the underplate arc magma in the juvenile crust. The εHf(t) and εNd(t) values of fertile porphyries increased from the Jiru, Gangjiang, to Qulong deposit indicating increased mantle material additions from the west to the east section of the GPCB. These variations in mantle components have led to an increase in the size of the porphyry Cu deposits from Jiru to Gangjiang, and then to Qulong. [ABSTRACT FROM AUTHOR]

A 3-D lithospheric resistivity model is obtained with 699 MT stations. The upper-mantle low-resistivity anomalies beneath the eastern SCB show a spatial distribution that is gradually shallowing from south to north, probably indicating that the asthenospheric materials are upwelling from south to north, corresponding with the changing progressively of magma and metallogenic activities. [Display omitted] • The 3-D lithospheric resistivity structure of the lithosphere in South China is obtained by inverting 699 MT stations. • The resistivity structure and disposition of four metallogenic belts in the South China Block are outlined. • The upper-mantle low-resistivity anomalies show a spatial distribution of gradual shallowing, indicating the asthenospheric upwelling from south to north. The South China Block (SCB) is located at the junction of the Pacific, Eurasian, and Indo-Australian plates. Their interaction led to large-scale multi-stage mineralization in the SCB during the Mesozoic. Several regional ore-concentration areas, such as the Middle-Lower Yangtze Metallogenic Belt (MLYMB), the Qinzhou-Hangzhou Metallogenic Belt (QHMB), the Wuyishan Metallogenic Belt (WYMB), and the Nanling Metallogenic Belt (NLMB) were formed during this process. However, the dominant mineral types of these metallogenic belts are different. To study the deep mechanisms of the different metallogenic types developed in the same tectonic background at almost the same period, the magnetotelluric sounding (MT) data from 691 sites located mainly within the eastern SCB are employed to obtain a regional lithospheric 3-D resistivity model. It could be concluded from the resistivity model that deep low-resistivity anomalies and mantle upwelling channels mainly controlled almost all the Mesozoic deposits. Large-scale low-resistivity bodies extend from the crust to the upper mantle beneath the MLYMB and the QHMB, interpreted as channels of mantle-derived magma and melts/fluids containing metallogenic elements upwelling. However, the MLYMB and the QHMB have different upper crustal ore-conducting and ore-controlling structures, thus forming porphyry copper and copper-bearing tungsten deposits. Small-scale low-resistivity anomalies are invading the high-resistivity crust in the NLMB. And remelting the upper crust, mixing, and intrusion of crust-source magma, enriching tungsten-tin elements near the NLMB. Larger-scale low-resistivity anomalies exist deep in the WYMB, remelting the lower crust and resulting in the formation of porphyry copper in it. Significantly, the upper-mantle low-resistivity anomalies beneath the eastern SCB show a spatial distribution that is gradually shallowing from south to north, probably indicating that the asthenospheric materials are upwelling from south to north, corresponding with the changing progressively of magma and metallogenic activities. We propose that the lithospheric delamination and asthenospheric upwelling caused by the far-field effects of the Paleo-Pacific Plate subduction are the sources of solid magmatic activities and related metallogeny. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Dongga Au deposit can be classified as subepithermal deposit. • Fluid mixing between magmatic water and meteoric water triggers gold precipitation. • The Dongga and No.2 deposits constitute a porphyry system, reflecting a continuous fluid evolution. The Dongga Au deposit (9.55 t Au; average grade = 6.9 g/t [up to 61.6 g/t]) is located in the Xiongcun giant porphyry Cu–Au district of the Gangdese porphyry Cu belt, Tibet. Its mineralization age, ore-forming processes, and relationship to adjacent porphyry mineralization remain unclear. To address this, we conducted a geological, pyrite Re–Os dating, He–Ar–H–O–S–Pb isotopic, and fluid inclusion study of the Dongga deposit. Pyrite samples from ore-bearing chlorite–sulfide veins yielded a weighted-mean Re–Os age of 178.4 ± 2.6 Ma (MSWD=0.01), implying the deposit formed during the Early Jurassic. Fluid inclusion analyses yielded homogenization temperatures of 237–360 °C for quartz–sulfide veins and 125–201 °C for late quartz veins, with corresponding salinities of 2.7–43.8 and 0.9–9.9 wt% NaCl eq , respectively. Fluid inclusion analyses of pyrite samples yielded 3He/4He and 40Ar/36Ar values of 0.50–1.08 Ra and 325.1–559.4, respectively, and δD and δ18O fluid values of –86.2 ‰ to –72.1 ‰ and –5.6 ‰ to 3.9 ‰, respectively. The He–Ar–H–O isotopic data suggest the mineralizing fluids were derived mainly from a crustal source with a small mantle contribution, and also contained a mixture of magmatic and meteoric waters. The S (δ34S = –1.57 ‰ to –0.55 ‰) and Pb (206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb are 18.17–18.41 ‰, 15.55–15.63 ‰ and 38.15–38.37 ‰, respectively) isotopic compositions of pyrite suggest the ore-forming metals were derived from a magma source in the mantle containing minor amounts of subducted sediment. Based on the geology, and isotopic and fluid inclusion data, we infer that mixing between magmatic and meteoric waters was the main trigger of Au precipitation. In addition, based on the geochronological, spatial, and genetic relationships with the adjacent No.2 deposit in the Xiongcun ore district, we propose that the Dongga Au deposit is a sub-epithermal deposit, which represents the transition between porphyry and epithermal deposits. The two deposits constitute a porphyry system and record the continuous evolution of hydrothermal fluids transported outwards in a porphyry system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Semi-supervised machine learning model was developed for identifying metallogenic settings of porphyry copper deposits. • SHAP values reveal the systematic chemical differences between zircons formed in different tectonic environments. • A new zircon trace element discriminant diagram was developed for identifying tectonic settings of PCDs. Porphyry copper deposits (PCDs), as main sources of Cu resources worldwide, have attracted great attention for both scientific research and mining purposes in the past decades. The formation of PCDs is closely related to magmatic-hydrothermal system formed in both (continental/oceanic) arc and non-arc environments. Many low-dimensional geochemistry discriminants were developed for identifying the tectonic environments where ore-related magmas formed. However, long-term geological processes may obscure the geochemistry information recorded in rocks and minerals, which inevitably introduces uncertainties for identifying tectonic environments when using the low-dimensional discriminant diagrams. Here, we proposed a semi-supervised machine learning (ML) approach based on zircon chemistry data (spanning 16 elements) to identify the tectonic environments of PCDs. The results show that the semi-supervised models perform better in identifying the tectonic environments compared to the conventional low-dimensional discriminants. Moreover, as another benefit of big data analysis, ML model can clarify the systematic geochemistry differences of igneous zircons formed in different tectonic environments. The results suggest that (U+Th)/Yb and LREE/HREE are the top two important zircon chemical features for distinguishing PCDs formed in arc or non-arc environments. Specifically, zircons from non-arc show higher (U+Th)/Yb compared to that of continental arc, while zircons from island arc show lowest (U+Th)/Yb and LREE/HREE. Finally, the semi-supervised learning model was applied to the Dexing porphyry copper deposit to approach the longstanding debate regarding the underlying metallogenic setting. The results support the viewpoint that the Dexing porphyry copper deposit was formed in an intracontinental (non-arc) environment related to asthenosphere upwelling. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zircon U-Pb ages indicate late Carboniferous to early Permian magmatic activity. • Dabate intrusions originate from melting of lower crust mixed with mantle materials. • The intrusions are A 2 -type granites formed in post-collision extensional environment. The Dabate deposit in the West Tianshan Orogenic Belt is a large porphyry Mo-Cu deposit with obvious zoning feature. The Dabate pluton is closely related to mineralization associated with the rhyolite and granite porphyries. Copper (Cu) mineralization occurs on the margin of the rhyolite porphyry, and molybdenum (Mo) mineralization occurs in the interior of the rhyolite porphyry. Petrology, zircon U-Pb isotopic data, whole-rock geochemistry, and Sr-Nb-Hf-Pb isotopic data of the rhyolite and granite porphyries in the Dabate Mo-Cu mining zone and to discuss the properties, sources, evolution, and tectonic environment of the magma. Zircon U-Pb age dating shows that the rhyolite porphyry and granite porphyry were formed in 300.1 ± 1.3 Ma and 290.4 ± 5.2 Ma, respectively, and they are geochemically similar. Both are characterized by negative Eu anomalies (δEu = 0.09–0.15 and 0.10–0.11, respectively) and are slightly rich in light rare earth elements (LREE) but depleted in high-field-strength elements (HFSE), which indicates that they are both A 2 type granites that underwent high differentiation. The Sr isotope (I Sr) values for the rhyolite and granite porphyries range from 0.70564 to 0.70658 and 0.70833–0.70954, respectively. The Nd isotopic composition [ε Nd (t)] values for both are negative but close to zero (−0.25 to −0.46 and −0.65 to −1.10, respectively), and the two-stage depleted mantle Nd model ages (T DM2 (Nd)) are 1.07–1.10 Ga and 1.11–1.14 Ga, respectively. Zircon ε Hf (t) values are 7.29–11.97 and 6.26–11.08 for rhyolite porphyry and granite porphyry, respectively, and the two-stage Hf model ages (T DM2 (Hf)) are 550–848 Ma and 605–916 Ma, respectively. The initial Pb isotope ratios for the rhyolite and granite porphyry are close at (206Pb/204Pb) i = 18.26–18.65, (207Pb/204Pb) i = 15.54–15.64, and (208Pb/204Pb) i = 38.19–38.57. These results indicate that the two porphyries have a mixed source, likely originating from the partial melting of mantle blended with some recently formed lower crust material. The geochronology, geochemistry, and Sr-Nd-Hf-Pb isotope data of existing intrusions in the West Tianshan imply that the Late Carboniferous to Early Permian Dabate area was underplated in a post-collisional extensional setting, and A 2 -type granite intrusions with related Mo-Cu mineralization were formed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Qi189 porphyry gold deposit has mantle component up to 37%. • Gold enrichment is controlled by changes in the pH, log f O 2 , log f S 2 , and log f Te 2. • Precipitation of native Au and Au-bearing telluride is significant for Au enrichment. The Qiyugou gold orefield is situated in the Eastern Qinling. It is a magmatic hydrothermal system, which includes cryptoexplosive breccia-type, vein-type, and porphyry gold deposits. However, the gold sources and physical–chemical conditions of precipitation of the newly discovered porphyry gold deposit, the Qi189, have not yet been well studied. It also hinders the comprehensive understanding of magmatic–hydrothermal gold systems in the Qiyugou gold orefield. Thus, detailed field and microscopic observations, C–O–He–Ar isotopic analysis, in situ major/trace element analysis, and thermodynamic studies on the Qi189 porphyry gold deposit have been carried out in this study. This deposit has three hydrothermal stages: the (I) early quartz–K-feldspar–molybdenite–magnetite stage, (II) middle quartz–sericite–pyrite–Te–Bi-mineral stage, as well as (III) late calcite–quartz stage. The carbon and He–Ar isotopic compositions suggest deep-seated sources of ore-forming fluids with mantle component proportions of up to 37 %. Oxygen isotopic compositions indicate the gradual involvement of more meteoric water in ore-forming fluids during stages I–III. The meteoric water input and reduction in temperature and pressure in the early stage II increased oxygen fugacity and decreased the pH values of ore-forming fluids. Then, in hematite and sulfides formation during late stage II, the oxygen and sulfur fugacities of ore-forming fluids gradually decreased. Precipitation of native gold and Au-bearing telluride grains with quartz-sericite alteration in stage II is significant for Au enrichment, which occurred under acidic (pH = 3.64–5.71), low-log f O 2 (<-34.86), low-log f S 2 (−13.07 to −11.13) and low-log f Te 2 (−15.55 to −10.32) conditions. Therefore, abundant mantle components and changes in the pH, log f O 2 , log f S 2 , and log f Te 2 of the ore-forming fluids play important roles in gold enrichment. Combined with previous studies, this work also provides some new evidence for identifying a magmatic-hydrothermal gold system in this district, including similar sulfide trace elements, δ13C V-PDB compositions, and changes in log f O 2 and log f S 2 of various types of gold deposits in a gold orefield. [ABSTRACT FROM AUTHOR]

[Display omitted] • Five ore-forming stages are recognized in the Yechangping porphyry-type orebodies. • Fluid characteristics suggest that Yechangping is a Dabie-type porphyry Mo deposit. • The process of fluid immiscibility, boiling, and mixing cause the mineralization. • Magmatic-hydrothermal system of Yechangping deposit extends to depths of 10 km. Dabie-type porphyry Mo deposits have recently emerged as a distinct subtype of porphyry Mo deposits, but questions remain about the magmatic-hydrothermal fluid evolution in the formation of this type of deposit. Here, well-developed fluid inclusions in quartz phenocrysts, unidirectional solidification textures (UST), and quartz veins in the Yechangping porphyry Mo-W deposit, Qinling Orogen, completely record the magmatic-hydrothermal mineralization process. The characteristics and evolution of the ore-forming fluid in this deposit are investigated through petrography, microthermometry, and laser Raman spectroscopy analysis of fluid inclusions at different stages in order to improve our understanding of the fluid evolution in the genesis of Dabie-type porphyry Mo deposit. The mineralization process in the porphyry-type orebody can be divided into three periods and five stages: (1) magmatic period, including quartz phenocrysts (stage 1); (2) magmatic-hydrothermal transition period, including UST (stage 2); (3) hydrothermal period, including quartz ± K-feldspar veins (stage 3), quartz-molybdenite veins (stage 4), and calcite ± quartz veins (stage 5), where stage 4 is the main ore-forming stage. The fluid inclusions in quartz and calcite can be recognized as pure CO 2 (PC type), CO 2 -H 2 O (C type), daughter minerals-bearing (S type), and H 2 O (WV type and WL type) inclusions. Ore-forming fluid is initially high temperature, high salinity, and CO 2 -rich, belonging to the H 2 O-CO 2 -NaCl (±KCl) system suggested by the fluid inclusions identified in UST. The estimated lithostatic pressures of stage 1 range from 284–362 MPa, corresponding to depths of 10.3 to 13.2 km, which are consistent with the formation depth of the underlying magma chamber. The presence of UST in stage 2 indicates that the magma was saturated with fluid. Due to the fluctuating pressure (123–260 MPa) in UST of stage 2, fluid immiscibility happened soon after the fluid exsolution and is inferred to occur between the CO 2 -rich and aqueous phases. Then, the fluid boiling and mixing occurred in stages 3 and 4, respectively. The estimated pressures of stage 4, which represent the main mineralization stage, range from 45–175 MPa, corresponding to depths of 4.6–6.4 km. The immiscibility of CO 2, along with the fluid mixing-induced cooling and dilution, caused an increase in p H and a decrease in oxygen fugacity, which serves as a crucial mechanism for Mo mineralization at the Yechangping deposit. Stage 5 is characterized by low temperature (185–309 °C) and low salinity (2.9–8.7 wt% NaCl equiv.). The primary high temperature, high salinity, CO 2 -rich fluids, and relatively deep ore-forming depth suggest that the Yechangping deposit is a typical example of a Dabie-type porphyry deposit. The characteristics of fluids and the variation in estimated depth at each stage record the evolutionary process of a magmatic-hydrothermal system extending to depths of nearly 10 km in the Yechangping deposit. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Au-bearing diorite porphyry was derived from the mixture of crustal and mantle components. • The hydrothermal fluids related to Au mineralisation were primarily magmatic in origin. • The Au finally integrated with S and Si and oxidized to form Au–bearing hematite and magnetite. Gold (Au) is a precious metal that has played an important role in the development of the global economy. It is therefore important to better define the genesis of Au mineralisation as an aid to focus exploration as the consumption of Au increases. The Dashui goldfield contains a super large Au resource of over 120 t (tonnes) in the West Qinling Orogen, central China. Despite several studies have focused on the genesis of the Dashui goldfield, the original physico–chemical natures of magmatic and hydrothermal evolution remain unclear. Biotite and apatite in the mineralised diorite porphyry of the goldfield are sensitive to the changes in the physico–chemical conditions and the evolution of magmatic and hydrothermal fluids, and thus provide important keys to address these issues. Hence, we conducted detailed in–situ major and trace element studies of biotite and apatite from the ore–bearing diorite porphyry in the Dashui goldfield. Our aim is to elucidate the physico–chemical conditions, magma source, and magmatic and hydrothermal evolution processes during the deposition of the gold, and to enhance the understanding of the Au genesis in the West Qinling Au province. Using the geochemistry of magmatic apatite, and magmatic and hydrothermal biotite, we have found that the crystallisation temperature and pressure along with emplacement depth of diorite porphyry were constrained at ∼ 737–791 °C, 1.08–1.73 kbar, and 3.94–6.30 km. The diorite porphyry has the geochemical affinities with calcium alkaline orogenic suites derived from a mixed crustal and mantle source. During the early emplacement of diorite porphyry, the melt had a high oxygen fugacity and was highly enriched in Au. During the late magma crystallisation of diorite porphyry, the magma was enriched continuously in most elements with the Ba/Rb ratios in the biotite varying from 10 to 5, and most of the Au was hosted by pyrite. Additionally, elements were continuously dissolved into fluids generating Cl–rich hydrothermal fluids during the evolution of the magma. During hydrothermal evolution, Au is migrated with As and Sb in the vapour phases of fluids, whereas Au migrated with Cl in the liquid phase. When temperatures dropped to ∼ 200–400 °C, Au started to combine with S and Si in the liquid phase of fluids. Subsequently, hydrothermal fluids interacted with host carbonate to form the Dashui goldfield, Au during this stage was also transported and hosted in magnetite, hematite, and quartz within the carbonate rocks. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zircon U–Pb data indicate the Houyu granite formed during 137–135 Ma. • Molybdenite Re-Os data indicate that the Houyu porphyry Mo-polymetallic deposit occurred at 134.94 Ma. • The Houyu Early Cretaceous I-type adakitic porphyry was formed through the partial melting of an ancient thickened lower continental crust. • The Houyu Mo-polymetallic mineralization are linked to the lithospheric thinning of the NCC. Porphyry-related molybdenum deposits formed within the plate's interior are unique, yet the understanding of the magmatic hydrothermal Mo system remains limited. Houyu is a typical porphyry-related Mo-polymetallic deposit situated in the inner region of the North China Craton (NCC). The ore bodies are found in Archean biotite plagioclase gneiss and diorite, followed by Early Cretaceous quartz porphyry, granite porphyry, and brecciated porphyry. Zircon U-Pb dating reveals that the biotite plagioclase gneiss, quartz porphyry, and granite porphyry were formed at 2499.2 ± 7.8 Ma, 135.19 ± 0.67 Ma, and 137.65 ± 0.84 Ma, respectively. Molybdenite Re-Os dating indicates a mean age of 134.94 ± 0.76 Ma and an isochron age of 134.7 ± 1.5 Ma, linking the Mo-polymetallic mineralization closely to the Early Cretaceous porphyry. The Houyu Cretaceous porphyry exhibits enrichment in light rare earth elements (LREEs), depletion in heavy rare earth elements (HREEs), and distinct positive Eu anomalies. Additionally, they are enriched in fluid-mobile large-ion-lithophile elements (LILEs) and significantly depleted in high-field-strength elements (HFSEs). These geochemical attributes suggest that the Cretaceous porphyry belongs to I-type adakitic granites. All samples exhibit consistently negative ε Nd (t) values ranging from −15.76 to −14.87 and ε Hf (t) values between −20.69 and −14.78, along with restricted 206Pb/204Pb (16.557–16.663), 207Pb/204Pb (15.262–15.300), and 208Pb/204Pb (36.601–36.747) ratios, indicating that they were derived from an ancient thickened lower continental crust (LCC). The Cretaceous magmatism and mineralization of the Houyu Mo-polymetallic deposit could be closely linked to the lithospheric thinning and destruction of the NCC triggered by the Paleo-Pacific or Izanagi Plate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Unidirectional solidification texture can chronicle the magmatic-hydrothermal evolution. • Multi-generational quartz distinguished by CL textures manifests the overall evolutionary history at Lailisigaoer. • Aluminum, Ti, Na and K can directly or indirectly signify variations in CL intensity of quartz. • Decompression, cooling, and the CO 2 concentration in hydrothermal fluid trigger Mo precipitation at 3.4–3.6 km. The Lailisigaoer deposit is a typical porphyry Mo deposit located in the late Paleozoic Boluokenu metallogenic belt of Western Tianshan, NW China. This study aims to understand molybdenum mineralization and the dynamics of magmatic-hydrothermal fluid within the porphyry system, focusing on fluid inclusion, cathodoluminescence textures, and trace elemental composition in various generations of quartz. Six vein types in the Lailisigaoer deposit are classified as comb quartz veins with unidirectional solidification texture (UST, Q I), actinolite/biotite ± quartz veinlets (M-type, Q II), quartz-chalcopyrite vein (A-type, Q III), quartz-molybdenite vein (B-type, Q IV), quartz-pyrite vein (D-type, Q V) and quartz-carbonate vein (E-type, Q VI). Micro thermometry data indicate decreasing homogenization temperatures in primary fluid inclusions from UST to E-type veins. The magmatic-hydrothermal fluids associated with UST and M-, A-, B-, D-, E-type veins underwent a transition from high temperature (342–495℃), high-pressure (∼1.25 kb), and variable salinity (6.7–41.1 wt%NaCl) in the H 2 O-CO 2 -NaCl system to low-temperature (142–238℃), low-pressure (∼0.25 kb), and low-salinity (1.6–5.1 wt%NaCl) in the H 2 O-NaCl system. This evolution is reflected in the proportion of quartz with oscillatory zones decreasing and irregular quartz increasing, indicating a shift from turbulent to stable fluid conditions. Furthermore, a gradual reduction in Ti concentration (from 79 ppm in UST to 1.4 ppm in E-type quartz) suggests a decrease in fluid temperature during the magmatic-hydrothermal evolution. Mineralization primarily occurs in A- and B-type veins, with molybdenum precipitation attributed to fluid immiscibility in a medium–high temperature (240–368 ℃) and high pressure (∼0.95 kb) environment. The A-type veins (mean 31 ppm in Ti concentrations) consist of equigranular (dark-core) (Q III-1) and patchy inhomogeneous CL-gray quartz (Q III-2). The B-type veins (mean 24 ppm in Ti concentrations) are characterized by equigranular (bright-core) inhomogeneous quartz (Q IV-1) with growth zones that are cemented by later mosaic homogeneous CL-gray quartz (Q IV-2). Based on the quartz-Ti thermometer, the mineralized veins (A- and B-type) were confined to be formed at depths of 2.8–3.6 km, with molybdenum mineralization occurring at 3.4–3.6 km. Molybdenum mineralization initiates during the Q IV-1 crystallization period in magmatic-hydrothermal fluids and terminates in the Q V-2 generation. [ABSTRACT FROM AUTHOR]

In this study, diaspore-pyrophyllite alteration zone, chlorite-sericite alteration zone and propylitic alteration zone were first identified in the deep drill core of the Zijinshan Cu-Au deposit, which gives way upward to quartz-alunite-kaolinite zone, quartz-alunite zone and the silicic alteration zone. In the Xi'nan Cu-Mo prospect, diaspore-pyrophyllite alteration zone was first recognized in the shallow level with the chlorite-sericite alteration zone and propylitic alteration zone in the deeper level. Andalusite- sericite ± diaspore alteration zone was first recognized in the upper part of the Luoboling Cu-Mo deposit and the deeper part of the Wuziqilong Cu deposit. It indicates that a pervasive occurrence of diaspore −pyrophyllite ± andalusite alteration zones with higher wAlOH values (average of 2203 nm) in the Zijinshan ore field, which may potentially represent a transitional environment between the top of porphyry alteration zones and the base of advanced argillic alteration zones. The Zijinshan ore field constitutes a porphyry-epithermal system with multiple paleo-thermal centers. Mineral assemblages and high wAlOH values suggest the potential presence of large porphyry intrusion in the deep parts of the Zijinshan Cu-Au deposit. However, the deep andalusite-sericite alteration zone in the Wuziqilong Cu deposit shows greater potential for uncovering porphyry. Simultaneously, the Xi'nan Cu-Mo prospect exhibits the potential for exploring a porphyry mineralization in its deep parts in southwest, which may be genetically connected to the Longjiangting transitional Cu deposit. [Display omitted] • In this contribution, a pervasive occurrence of diaspore −pyrophyllite ± andalusite alteration zones were first recognized in the Zijinshan ore field, which may potentially represent a transitional environment between the top of porphyry alteration zones and the base of advanced argillic alteration zones. The andalusite-sericite alteration zone is indicative of a porphyry environment with wAlOH > 2203 nm. • From the early potassic alteration zone to the late kaolinite-dickite alteration zone, the wAlOH value gradually decreases. In the early stages, white mica is enriched in Mg with lower Fe content. Due to the influence of Fe3+, the relationship between wAlOH and Al, as well as Fe + Mg + Mn, becomes less pronounced. • The Zijinshan ore field constitutes a porphyry-epithermal system with multiple paleo-thermal centers, which may located at the deep part of the Zijinshan Cu-Au deposit, Wuziqilong Cu deposit and Xi'nan prospect. The Wuziqilong Cu deposit with deep-seated andalusite-sericite alteration zone shows greater potential for exploring porphyry bodies in the deep. The Zijinshan ore field is situated in the southeastern part of China. in which contains the large Zijinshan high-sulfidation Cu-Au deposit, the Luoboling porphyry Cu-Mo deposit, the Yueyang low-sulfidation Au-Ag deposit, the Longjiangting and the Wuziqilong tansitional Cu deposit, and the Xi'nan porphyry Cu-Mo prospect. Debates on genetic relationship among these deposits, especially the relationship between the Zijinshan Cu-Au deposit and the adjacent Luoboling deposit is a question of importance for further exploration in this ore field. In this contribution, the alteration mineralogy, alteration texture, zonation and mineral chemistry, in combination with shortwave infrared spectroscopy (SWIR) analysis of white mica were used to help focus exploration and assessment of hydrothermal deposits in the Zijinshan ore field. In this study, diaspore-pyrophyllite alteration zone, chlorite-sericite alteration zone and propylitic alteration zone were first identified in the deep drill core of the Zijinshan Cu-Au deposit, which gives way upward to quartz-alunite-kaolinite zone, quartz-alunite zone and the silicic alteration zone. In the Xi'nan Cu-Mo prospect, diaspore-pyrophyllite alteration zone was first recognized in the shallow level with the chlorite-sericite alteration zone and propylitic alteration zone in the deeper level. Andalusite- sericite ± diaspore alteration zone was first recognized in the upper part of the Luoboling Cu-Mo deposit and the deeper part of the Wuziqilong Cu deposit. It indicates that a pervasive occurrence of diaspore -pyrophyllite ± andalusite alteration zones in the Zijinshan ore field, which may potentially represent a transitional environment between the top of porphyry alteration zones and the base of advanced argillic alteration zones. Minerals of the white mica group are extensively distributed in various alteration zones of the Zijinshan ore field. The SWIR analysis of white mica indicated that the wavelength position of the Al-OH (∼2,200 nm; wAlOH) absorption feature increases gradually from the shallow kaolinite-dickite alteration zone to the deep potassic alteration zone. In the advanced argillic alteration zones, the range of wAlOH values of white mica is less than 2205 nm. Conversely, in the porphyry alteration zones, it always exceeds 2205 nm. It is evident that the andalusite-sericite alteration zone with higher wAlOH values (average of 2203 nm) is always proximal to the porphyry mineralization, which may act as indicators for deep porphyry prospecting. The results of electron probe microanalysis (EPMA) reveal that the early enrichment of Mg and depletion of Fe in white mica can be attributed to the preferential incorporation of Fe into iron oxides and iron sulfides in the potassic and propylitic alteration zones. Overall, there is a negative correlation between wAlOH and Al, while wAlOH exhibits a positive correlation with the sum of Fe + Mg + Mn. The distribution characteristics of alteration zones and the variation patterns of the wAlOH of white mica indicate that there are probably several paleo-thermal centers in the deep parts of the Zijinshan ore field, located respectively in the deep parts of the Xi'nan Cu-Mo prospect and the deep part of the Zijinshan Cu-Au deposit and the deep parts of the Wuziqilong Cu deposit, and the latest seems to be more fertile and deserves further exploration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Molybdenite Re-Os and sericite 40Ar-39Ar dating results show that the Xinan deposit is formed at 109 ∼ 108 Ma. • Fluid cooling, oxygen fugacity reduction, and CO 2 escape control Cu-Mo mineralization of the Xinan deposit. • Possible porphyry mineralization center at depth is inferred by fluid inclusion microthermometry. The Xinan deposit, a newly discovered porphyry Cu-Mo deposit in the Zijinshan orefield, Fujian Province, exhibits distinct alteration and porphyry mineralization stages, including the potassic, propylitic, and phyllic alteration stages. The phyllic stage is further divided into molybdenite, chalcopyrite, and pyrite sub-stages. Molybdenite Re-Os model age (108.3 ± 1.1 Ma) and concomitant sericite 40Ar/39Ar plateau age (109.0 ± 6.0 Ma) indicate that the Xinan Cu-Mo deposit was formed at 109 ∼ 108 Ma. Four types of fluid inclusions have been identified at the Xinan deposit, including vapor-rich, liquid-rich, and opaque daughter mineral-bearing subtypes with minor transparent daughter mineral-bearing subtypes. Fluid inclusion microthermometry measurements reveal that the potassic alteration stage exhibits homogenization temperatures of 375–475 °C and salinities range of 4–20 wt% NaCl eqv., suggesting slight fluid boiling. Chlorite geothermometer suggests temperatures of the propylitic alteration stage range from 261 to 336 °C, averaging at 303 °C. The molybdenite, chalcopyrite, and pyrite sub-stages have homogenization temperatures of 325–400 °C, 325–350 °C, and 300–350 °C, respectively, with corresponding salinities of 2–10 wt% NaCl eqv., 4–8 wt% NaCl eqv., and 2–4 wt% NaCl eqv.. The Laser Raman spectroscopy results show that the fluid inclusions in the Xinan deposit consist of H 2 O with minor CO 2 , hematite, chalcopyrite, and halite. The evolution of the ore-forming fluids in the Xinan porphyry Cu-Mo deposit is characterized by a transition from high-temperature, low- to moderate-salinity, oxidized, and CO 2 -bearing conditions during the potassic alteration stage, to moderate- to high-temperature and low-salinity conditions during the propylitic alteration stage. The subsequent phyllic alteration stage, which overprints on the potassic and partial propylitic alteration stages, is marked by moderate- to high-temperature, low-salinity, and low-oxygen fugacity environments. The primary mechanisms driving mineralization in the Xinan porphyry Cu-Mo deposit are thus identified as the reduction in temperature and oxygen fugacity, coupled with CO 2 escape. In contrast to the Luoboling-Jintonghu porphyry Cu-Mo deposit, the ore-forming fluid of the Xinan deposit is characterized by lower temperatures, salinity, and CO 2 contents, and reduced fluid boiling. This suggests a relatively subdued porphyry-type mineralization. The lack of a distinct potassic alteration zone in the Xinan Cu-Mo deposit suggests the potential existence of a deeper, higher temperature and salinity porphyry mineralization center beneath this deposit. [ABSTRACT FROM AUTHOR]

[Display omitted] • Based on the EPMA analyses, sulfosalts were identified at the Chodarchay deposit. • The chalcopyrite and sphalerite host solid-solution Ag, and the chalcopyrite hosts Ag-sulfosalt. • The sphalerite hosts nano-Au. The Au-Ag exists in the neyite, emplectite and gustavite. • The sphalerite precipitated from 220 to 280 °C, Bi assemblages at > 350 °C. • The supergene enrichment of Ag and Au depends on the presence of Mn. The Chodarchay overprinting epithermal on porphyry mineralization occurs in the Tarom-Hashtjin subzone of the Alborz magmatic arc in northwestern Iran. Rock units include intrusions (phases I and II) and volcano-volcaniclastic rocks. The alteration types consist of potassic, phyllic, argillic, and propylitic. The porphyry type is mostly accompanied by potassic alteration. The Chodarchay Fault implies two extensional and compressional mechanisms. The porphyry type is associated with the extensional and the epithermal type with the compressional stage of the fault. Mineralization occurred mainly inside the Eocene volcanic and volcano-sedimentary rocks; some ores are associated with the Late Eocene quartz monzonite. The mineralization is divided into three zones from depth to surface: 1) Hypogene sulfide zone (deep); 2) Enriched supergene sulfide zone (near-surface); 3) Oxidized and leached zone (surface). The major sulfide minerals consist of chalcopyrite, pyrite, sphalerite, and galena. Based on the results of the new analyses, chalcopyrite hosts Ag as a solid-solution and contains Ag-rich Bi-sulfosalt micro-inclusions. Non-constant Cd/Zn ratio in the chalcopyrite can indicate varying physiochemical conditions during its crystallization. Low As contents in the pyrite caused relatively clean pyrite with very few elements. The Ni concentrations in the pyrite imply that it was sourced from mantle mafic–ultramafic rocks. Sphalerite is the only Au-host mineral among the sulfide minerals as a nano-mineral phase. Solid-solution Ag exists in the sphalerite. The sphalerite Fe/Zn ratios show that it was precipitated between 220 and 280 °C. Silver and Bi have the highest measured concentrations among all analyzed elements in the galena, mainly partitioning within the galena, but Hg and Cd are abundant in the sphalerite. Bornite is one of the major carriers of Ag and Bi. Silver and Bi exhibit considerable variations in the Cu-(Fe) sulfides. A new occurrence of sulfosalt minerals was identified at Chodarchay (N = 14). The discovered Bi-sulfosalts include cuprobismuthite group minerals (cuprobismuthite, hodrushite, and paderaite), aikinite-bismuthinite series (aikinite and friedrichite), emplectite, makovickyite, galenobismutite, gustavite, heyrovskyite, neyite, cupropavanite; and As-Sb-bearing Cu sulfosalts (watanabeite and colusite). This number of sulfosalts had not previously been reported from any of the Tarom or Alborz deposits or mines. The Au-Ag occurrence was reported from the neyite, emplectite, and gustavite. The Ag-rich minerals crystallize from fractionated fluids that cooled during rising. Silver-carrier sulfosalts may have been exsolution from pre-existing Ag-bearing chalcopyrite in the cooling system. Most of the Ag-bearing sulfosalt minerals formed at the margins and fractures of the chalcopyrite, indicating that the cooling started from these points. Thus, Ag at Chodarchay is hosted inside Cu-(Fe) sulfides, the significant part of them being chalcopyrite and Ag-rich sulfosalt micro-inclusions inside the chalcopyrite. The fluid temperature for the Ag and chalcopyrite precipitation is from 200 to 350 °C. Bismuth assemblages precipitated at > 350 °C. The cuprobismuthite group crystallizes at temperatures > 300 °C. The supergene process and rare secondary enrichment of Ag and Au took place in the oxidation zone; this enrichment is dependent on the presence of manganese. Based on the fire-assay results, the concentration of gold is greater at shallower depths. [ABSTRACT FROM AUTHOR]

[Display omitted] • High conductance zones, more than 10,000 S, detected in the mid-lower crust. • High conductance zones correspond with locations of Miocene porphyry copper deposits. • Alkali-rich volatile-rich melt can reconcile electrical, seismic and geochemical data. • A weakened mid-lower crust influenced deposit development. New evidence worldwide has linked the surface locations of mineral deposits and their crustal-scale electrical conductivity footprint. We examine the relationship between the Gangdese Miocene porphyry copper deposits, Tibetan Plateau, and the electrical conductivity signature from a three-dimensional model generated from 311 magnetotelluric measurements. The distribution of electrical resistivity throughout the crust and the conductance within the mid-lower crust (depth range of 25–70 km) is analyzed. The results clearly show that the large and ultra-large Miocene porphyry copper deposits coincide spatially with conductive zones and areas of very-high conductance (>10,000S) in the mid-lower crust. Computations are undertaken to determine the influence of water-bearing silicate melts and alkali-bearing (Na+ and K+) fluids on conductivity. Based on this, the bulk conductivity is interpretated to be caused by a system of alkali-rich volatile-rich partial melt. The alkali-rich volatile-rich magmatic-hydrothermal fluids facilitate the migration and concentration of metal ions originating in deep areas. The volumes necessary are much less than partial melt alone and can thus help to reconcile large conductivity variations with small seismic velocity variations. The electrical structure indicates the magma source area of anatexis in the lower crust, a multi-stage magmatic system with large mid-crustal and small upper-crustal magma reservoirs, and complex pathways related to rift zones. We determine that the conductive zones in the mid-lower crust have an influence on the development of the mineralization and the location of the mineral belt. [ABSTRACT FROM AUTHOR]

[Display omitted] • PRISMA imagery provides valid support in the delineation of hydrothermal and supergene alteration zones. • Spectral feature parameters aids in identifying and characterising alteration minerals. • Mineral mapping of Porphyry-Cu and IOCG systems assists in mineral exploration at the province- and district-scales. • Hyperspectral satellite interpretation helps in the delineation of new exploration targets. This study provides an overview of the application of hyperspectral imagery acquired by the Italian satellite mission "PRecursore IperSpettrale della Missione Applicativa" (PRISMA), for mapping hydrothermal and supergene mineral alteration zones associated with different Cu deposits in the Chilean Andes. Study areas include the Marimaca Copper Project in the Naguayán district (Antofagasta Province), hosting Late Jurassic – Early Cretaceous iron oxide-copper–gold mineralizations and the Río Blanco-Los Bronces district (Santiago Region) known for its Late Miocene – Early Pliocene copper-molybdenum porphyry deposits. These mineral systems exhibit hydrothermal alteration haloes extending over several kilometers, with upward and outward mineral zonation. To characterize the surface-exposed alteration, the satellite imagery was processed using a multiple feature extraction workflow targeting the relative abundances and compositions of specific supergene and hydrothermal alteration minerals, including Fe-oxides and hydroxides (hematite-goethite), phyllosilicates (micas-kaolinite-chlorite), hydroxyl-bearing sulfates (alunite-natroalunite-jarosite) and epidote. The results reveal a zonation from proximal sulfates (natroalunite to alunite) and Al-rich white mica (ranging from 0.3 km-wide for the area identified to the east of the Marimaca deposit to 1 km-wide in correspondence of the Los Sulfatos deposit, respectively) to distal Al-poor white mica (0.2 to 0.5 km-wide, respectively) and an outer chlorite-epidote zone. In the Marimaca Project area, the structurally-controlled alteration evolves west to east from chlorite-rich to phengitic white mica (Al-poor). A NNE-SSW trending supergene leached cap covers a 6 km-long and up to 2 km-wide area from north to south. Our study documents how spaceborne hyperspectral imaging spectroscopy can support mineral exploration by enabling non-invasive reconnaissance mapping of the outcropping rocks, providing specific targeting information for follow-up field surveys and drilling campaigns. [ABSTRACT FROM AUTHOR]

Rutile trace element data from Duolong district and literature are integrated to develop a Partial Least Square-Discriminant Analysis (PLS-DA) multivariate statistics plots that can discriminate porphyry Cu deposit rutile from orogenic gold and VHMS deposits (A), as well as lower-T and strong Cu mineralization related rutile in phyllic and advanced argillic alteration from potassic alteration stages (B). The PLS-DA plots are used to predict that stream sedimentary gold-bearing rutile (RtSAu, C) adjacent to the Tiegelongnan deposit may have been derived from the deposit, and mainly from low-temperature phyllic and advanced argillic alteration stages. This is further confirmed by a U-Pb age of 125.3 ± 4.7 Ma (n = 24, 2σ, D) for RtSAu (C), which is consistent with the main porphyry mineralization age of ∼120 Ma in the Tiegelongnan deposit. In general, our findings suggest the capability of using rutile from ore deposits and stream sediments, by combing the texture, geochemical compositions, geochronology, PLS-DA tools, and their spatial distribution, as a proxy mineral for the exploration of porphyry Cu deposits. [Display omitted] • Rutile can help discriminate different alterations in porphyry Cu deposits. • PLS-DA can discriminate porphyry rutile from that in other hydrothermal deposits. • Gold inclusion-bearing rutile in stream sediments may from epithermal events. • Integration of rutile geochemistry and geochronology can be a useful tool for exploration. Rutile is a common and stable mineral in porphyry Cu deposits, and morphology and geochemistry of rutile are recognized as a potential indicator mineral for exploration. In this study, we investigate physical features and chemical composition of hydrothermal rutile in the Tiegelongnan porphyry-epithermal system, as well as rutile in stream sediments nearby to establish a method to apply rutile as an exploration proxy. Four stages of hydrothermal rutile have been identified. Potassic alteration stage rutile (Rt1) is associated with biotite, with elongated and acicular shape and small grain size (20–50 μm). Rutile from lower temperature phyllic alteration (Rt2), quartz veins (Rt3), and advanced argillic alteration (Rt4), has characteristic sector zoning and larger grain size (50–150 μm). The sector zoning is more commonly present in Rt2, Rt3, Rt4, that are associated with high-grade Cu mineralization, and is associated with incorporation of W, Fe, V, Sn, and Zr. The earlier rutile (Rt1) also has a geochemical signature different from the other three types of rutile, characterized by significantly lower Al, Cu, Zr, Nb, Sn, Hf, and higher Sc and Fe contents. Low-temperature hydrothermal alteration stage rutile (Rt2, 3, 4) share many geochemical similarities, but Rt3 has higher Nb and Ta contents (median = 3371.0 and 176.0 ppm, respectively), whereas Rt4 has higher Sb content (median = 24.3 ppm). Rutile trace element data from this study and literature are integrated to develop a Partial Least Square-Discriminant Analysis (PLS-DA) multivariate statistics plots that can discriminate porphyry Cu deposit rutile from orogenic gold and VHMS deposits, as well as rutile from different alteration stages. The PLS-DA plots predict that stream sedimentary gold-bearing rutile (RtSAu) adjacent to the Tiegelongnan deposit are derived from the deposit, and mainly from low-temperature phyllic and advanced argillic alteration stages. This is consistent with geochemical similarity between the RtSAu and the Tiegelongnan low-temperature hydrothermal rutile (Rt2 + Rt4). This is further confirmed by a U-Pb age of 125.3 ± 4.7 Ma (n = 24, 2σ) for RtSAu, which is consistent with the main porphyry mineralization age of ∼ 120 Ma in the Tiegelongnan deposit. We infer that the RtSAu may have formed during the ∼120 Ma epithermal system at Tiegelongnan, which has already largely eroded. In general, our findings prove the capability of using rutile, by combing the texture, geochemical compositions, geochronology, PLS-DA tools, and their spatial distribution, as a proxy mineral for the exploration of porphyry Cu deposits. [ABSTRACT FROM AUTHOR]

[Display omitted] • Determination of tilting of crystalline bodies by low-T thermochronology tools. • The methodology applied to determine tilting is crucial for the exploration of PCDs. • Halilaga deposit exhumed by the coupling effects of Aegean extension and westward propagation of the North Anatolian Fault. • Aegean back-arc extension initiated at ∼ 24 Ma in the north of Western Anatolia. • Westward propagation of the North Anatolian Fault occurred no earlier than 2 Ma. Because most crystalline bodies lack intrinsic paleo-horizontal information, their tilting cannot be measured directly. Their vertical movement, however, may be tracked by low-T thermochronology (LTT) tools. Because tilting is caused by differential vertical movements, it can be understood if the rate of differential movements is determined. In this regard, here we apply a new LTT-based approach to calculate the orientation of a tilted crystalline body, the Halilaga Cu-Au deposit, in NW Anatolia. Orientation is consistent with the one calculated from a drillhole-based 3D model of the deposit. This reveals the significance of tilting calculations for the exploration of porphyry Cu deposits. On the other hand, and more importantly, it emphasizes the importance of tilting calculations for geological applications such as LTT-based exhumation histories of samples taken from vertical profiles, and paleomagnetic studies. AHe data from the Halilaga deposit reveals the earliest response to the Aegean back-arc extension at ∼ 24 Ma in the north of Western Anatolia. Lastly, thermal models, the new complementary datasets for the tectonic evolution of the region, show that the Halilaga deposit was exhumed to the surface by the coupling effects of Aegean extension and westward propagation of the North Anatolian Fault, which occurred not earlier than 2 Ma. [ABSTRACT FROM AUTHOR]

The numerical simulation framework for modeling porphyry magma cooling and crystallization. [Display omitted] • A hybrid numerical approach has been proposed for modeling magma dynamics. • This hybrid method combines numerical modeling and thermodynamics calculation. • Moderate initial magma temperature is favorable for porphyry mineralization. • Slow boundary heat transfer is beneficial for metal enrichment in porphyry magma. The ore-forming metals (such as Cu, Mo, and Au) and hydrothermal fluids necessary for the formation of porphyry copper deposits (PCDs) are separated and precipitated from the felsic magma during its cooling and crystallization process, due to changes in physical and chemical conditions triggered by magma ascending and emplacement. Magma cooling and crystallization process is influenced by various factors, mainly including the initial cooling temperature of magma, the startup speed of magma chamber circulation inherited from the pulsations of deep-seated magma, and the cooling rate caused by the contact between magma chamber and surrounding rocks. However, the precise mechanisms of these factors triggering the evolution of porphyry magma in the shallow crust and their role in controlling ore-forming during this process are still not clearly understood. Therefore, this study proposes to use multiphysics numerical modeling in conjunction with thermodynamic calculations to investigate porphyry magma cooling and crystallization control of mineralization. Firstly, based on the whole-rock geochemical data of porphyry intrusions in the world's famous Bingham Canyon cooper deposit, we utilized MELTS to calculate the thermodynamic properties including density, melt fraction, thermal conductivity and heat capacity of porphyry magma. Then, we established the finite element numerical model coupled heat transfer and fluid flow that employed these four thermodynamic properties to simulate the dynamic processes of porphyry magma cooling and crystallization. Finally, we conducted numerical modeling experiments by varying the three parameters, including the initial temperature and startup cycling speed of magma, as well as heat transfer coefficient at the up boundary of magma chamber, to investigate their controls on magma evolution and mineralization of PCDs via calculating and analyzing temporal and spatial variations of the magma temperature, crystallinity, velocity, and metal (i.e. copper) concentration. The results show that the evolution of a porphyry magma chamber is primarily controlled by its initial temperature and the heat transfer coefficient of its upper boundary. 900 °C is the most favorable initial cooling temperature for forming both porphyry magma plumes with high metal endowment, and connected tunnels for volatile to rapidly migrate upward and concentrate to apical parts of the magma chamber. A lower heat transfer coefficient, indicating a magma chamber in a relatively closed tectonic environment, is more beneficial for forming metal migration tunnels within the magma chamber. The startup cycling speed significantly influences the early circulation and convective patterns within the magma chamber, may leading to heterogeneous mixing of magmas with different properties inside the chamber. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lengjia monzogranite and Mo deposit were formed in 113 Ma. • High f O 2 enhanced porphyry Mo formation in Weidshanian suites. • Mesozoic granitoids formed by the drifting and subduction of Pacific and Izanagi plates. Oxygen fugacity is a key factor in controlling the formation of porphyry molybdenum deposits. We present new data on Lengjia monzogranite and compile the Mesozoic magmatism data of the Jiaodong Peninsula to elucidate the correlation between magma oxygen fugacity and porphyry Mo mineralization. Zircon U-Pb geochronology indicates that the formation of the Lengjia monzogranite occurred at 113.7 Ma, while molybdenite Re-Os geochronology shows that the Lengjia Mo deposit was formed at 113.5 ± 3.0 Ma. The Lengjia monzogranite, characterized by low Sr/Y ratios (12.28 ∼ 20.16), low Sr, and high Yb and Y concentrations, can be classified as a non-adakite I-type granite. It had low zircon ε Hf (t) values (–23.8 ∼ -13.8) and ancient T DM2 (Hf) (2047–2680 Ma) with variable zircon O isotopic compositions (5.82 ‰ ∼ 7.38 ‰). The Lengjia monzogranite was formed by partial melting of the Paleoproterozoic crustal source and mantle components metasomatized by slab-derived melt. The zircon trace element calculation revealed that the Weideshan suite had higher ΔFMQ values (0.32 ∼ 4.47, average is 2.27) compared to the Guojialing suite (-0.91 ∼ 2.88, average is 0.82) and Linglong suite (-1.81 ∼ 2.76, average is 0.37). The oxidized Weideshan suite resulted from the increased involvement of mantle metasomatized by slab-derived melt. The elevated oxygen fugacity promoted the porphyry Mo-metallogenic potential of the Weidshanian suite. We propose that the Linglong suite was related to the northwestward flat-slab (subhorizontal) subduction of the Izanagi plate (Paleo-Pacific plate), the Guojialing suite was formed by low-angle northwestward subduction of the Izanagi plate, and the Weideshan suite was related to the northwestward subduction and major slab rollback of the Pacific plate. [ABSTRACT FROM AUTHOR]

[Display omitted] • The volcano-plutonic complex was mainly generated by the partial melting of lower crust. • Mantle delamination generated heterogeneous magma and thus a variety of deposits. • Intracontinental tectonic transformation controlled the porphyry emplacement. The Yao'an Pb–Ag–Au deposit is located far from the present-day margin of the Yangtze Craton, providing an excellent example for studying the genesis of porphyries and associated polymetallic mineralization in intracontinental transpression settings. In situ zircon U–Pb ages and Sr–Nd–Hf–O isotopic data of the Yao'an porphyries in the intracontinental zone, combined with research data published for the Machangqing and Beiya ore-bearing porphyries in the cratonic margin, were used in this paper. Four-phase felsic rocks (∼33 Ma) and later mafic rock (∼31 Ma) were recognized in the Yao'an district. Of these, the third-phase syenite porphyry had a genetic link with Pb–Ag–Au mineralization, which occurred within the second-phase volcanic rocks and Mesozoic strata. In addition, the Yao'an porphyry showed high initial 87Sr/86Sr ratios (0.7087–0.7094) and enriched Nd (ε Nd (t) = −10.53 to −12.60) isotopic composition, with a wide range of zircon Hf (ε Hf (t) = −8.39 to −13.2) and δ 18O values (6.28 ‰–9.20 ‰). These features suggest that the Yao'an porphyries were produced by partial melting of an ancient lower crust mixed with continental lithospheric-mantle-derived melt, which are differed from the magma source of the Beiya and Machangqing porphyries. Given the nature sources of the porphyries, we conclude that the spatial variation of metal associations changing from the Cu ± Au ± Mo system at the cratonic margin to the Pb–Ag–Au deposits in the intracontinental zone in the western Yangtze Craton was likely controlled by different magma sources. The delamination of an overthickened continental lithospheric mantle in an intracontinental transpression setting was a geodynamic trigger for porphyry magma generation, ascent, and emplacement. [ABSTRACT FROM AUTHOR]

[Display omitted] • A comparative study between ore-related and barren suites in the Zijinshan orefield. • The high f O 2 is not the sole constraint in the Zijinshan orefield. • Apatites from the ore-related suites have lower Cl contents than the barren suites. The Zijinshan orefield (Fujian Province) is a representative Cu-Au-Mo-Ag porphyry-epithermal mineralization system in eastern China. It contains both Cu ore-bearing and ore-barren granitoids, which provide an opportunity to study the unique properties of fertile magmas. This study focuses on chemistry of minerals such as zircon, apatite, amphibole, and plagioclase in ore-related (zircon U–Pb ages of 103–101 Ma) and ore-barren (zircon U–Pb ages of 157–156 Ma and ∼105 Ma) granitoids to constrain the characteristics of mineralized magmas. The results of whole-rock geochemistry and zircon Hf isotopes suggest that both ore-barren and ore-related granitoids were derived from partial melting of the lower crust, with the ore-related magma being influenced by mantle materials. The analysis of mineral chemistry reveals that the Zijinshan Cu ore-bearing porphyry magmas have high oxidation states (ΔFMQ +0.23–+2.25), high water contents (4.4–4.9 wt%), and shallow emplacement depths (1.9–4.0 km). These magmatic conditions are favorable for fluid exsolution and mineralization, similar to the global Cu-fertile porphyry magmas, but distinct from regional pre-mineralization ore-barren igneous rocks. Apatites from the ore-related granitoids have significantly lower Cl contents (0.03–0.83 wt%) and higher F/Cl ratios (1.52–377) compared to coeval ore-barren monzogranites (Cl = 0.14–2.42 wt%; F/Cl = 0.07–2.82). Additionally, the apatites' volatile budgets, including X OH , X Cl and X F values, and their covariation relationship, in the ore-related intrusions are consistent with apatite crystallization in H 2 O-saturated conditions. This suggests that extensive fluid exsolution from the parent magma in the chamber plays a crucial role in the formation of porphyry Cu deposits from a low-Cl magma. These low-Cl-apatite intrusions have the potential to form porphyry deposits. Together, we propose that the high oxygen fugacity, high water contents, and fluid exsolution of the parent magma may have triggered the Zijinshan porphyry mineralization. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ore-bearing granodiorite porphyry crystallized at ca. 434 Ma, recording the early subduction of the Paleo-Tianshan oceanic plate. • The granodiorite porphyry was likely sourced from the partial melting of subduction-metasomatized mantle by slab fluids. • High magma oxidation state and water content are the key factors that controlled the generation of Early Paleozoic porphyry Cu mineralization in the Kalatag district. The Hongshi epithermal Cu deposit is located in the northern margin of the Dananhu arc in the East Tianshan Orogenic Belt, NW China. The Hongshi deposit is hosted by andesite and is famous for its lode type sulfide ores. Recently, the deep drill hole exploration shows a porphyry Cu mineralization and is predominantly hosted in granodiorite porphyry in the Hongshi. As for porphyry mineralization, the metallic minerals mainly include chalcopyrite, magnetite, and pyrite, with minor amounts of molybdenite. Ore minerals occur as dense dissemination and veins. Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) U–Pb dating of zircons showed that the ore-bearing granodiorite porphyry was emplaced at ca. 434 Ma, recording the early subduction of the Paleo-Tianshan oceanic plate. Major element geochemical characteristics show that granodiorite porphyry samples have A/CNK values of 1.04–1.10 and moderate Mg# values of 45–49, indicating an I-type granitoid attribute. Trace element geochemical analysis indicates that ore-bearing granodiorite porphyry samples exhibit obvious large ion lithophile elements (LILEs) enrichment, high field strength elements (HFSEs) depletion, together with mantle-like bulk Sr–Nd ((87Sr/86Sr) i = 0.706417–0.708601; ε Nd (t) = 6.3–7.0) and zircon Hf–O isotope signatures (ε Hf (t) = 15.5–21.7, δ18O = 3.8 ‰–4.7 ‰), indicating that they were generated from partial melting of metasomatized mantle by the subducted slab fluids. In situ S isotope results of pyrite (1.46 ‰–2.07 ‰) and chalcopyrite (0.79 ‰–1.93 ‰) imply that granodiorite porphyry magmas and volcanic rocks provided ore-forming components (S and metals) for porphyry Cu mineralization in the deep drill hole ZK7501. The ore-bearing granodiorite porphyry samples have high log f O 2 values ranging from − 12.4 to − 10.7, corresponding to ΔFMQ values of 0.6–5.2 (FMQ is the fayalite-magnetite-quartz buffer). Zircons from granodiorite porphyry have high Ce4+/Ce3+ ratios ranging from 74 to 187 and high Ti-in-zircon temperatures (764 to 869 °C). Electron microprobe analyses (EPMA) composition results of plagioclase, apatite and amphibole reveal that granodiorite porphyry magma had systematically high oxygen fugacity, high water contents (7.6–8.4 wt%), and low Cl contents (0.08–0.27 wt%), further demonstrating that granodiorite porphyry may be beneficial to the porphyry Cu mineralization in the deep drill hole ZK7501. Pyrite in the deep drill hole ZK7501 is enriched in Co, Ni, Ag, Cu, As, and Pb, but poor in Mn, Ga, Ge, Cd, In, Sn. Mn, As, Tl, Pb and Sb in pyrite substituted Fe2+ by coupled mechanisms, while Ag and Cu can enter the mineral lattice in the form of solid solution or micro-inclusions, which was also demonstrated by LA–ICP–MS mapping and textural studies. Pyrite shows variable Co/Ni ratios ranging from 10 and 455, indicating that ore-forming fluid originated from a magmatic source. The involvement of highly oxidized magmas is fundamental for the formation of porphyry Cu mineralization in an arc tectonic setting. Additionally, water concentrations also play an important factor that controlled metal fertility of the Early Paleozoic porphyry Cu mineralization in the Kalatag district. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface exploration proxies related to distal porphyry mineralization were identified from geological, geochemical, and geophysical datasets. • Conventional cell-based association (CBA) applied to exploration proxies to define their association with Cu–Au mineralization. • By assigning proper weights to exploration proxies, an innovative CBA method was used to locate potential targets for drilling. The presence of various spatial exploration proxies (predictor patterns) as vectors to distal porphyry mineralization in surrounding areas of a known outcropping mineralized porphyry center at the Dalli Cu–Au deposit in Iran provided evidence for the occurrence of similar porphyry mineralization in the subsurface. Factor analysis was applied to soil geochemical data from the Dalli South Hill area to define favorable geochemical variables and to create surface multi-element anomaly maps reflecting the presence of porphyry Cu–Au mineralization in the subsurface. Reduction-to-pole and analytical signal filters were applied to ground total magnetic field data to define high magnetic signatures that could be associated with potassic alteration and porphyry mineralization in the subsurface. Then, a data-driven cell based association (CBA) data integration method was applied to the favorable spatial proxies to define their association with Cu–Au mineralization and locate subtle high potential targets (cells) for drilling. The conventional CBA algorithms did not consider weights for the spatial proxies, and by using the ascendant hierarchical clustering (AHC) algorithm the results were classified into a binary map to show favorable and unfavorable cells with scores of 1 and 0, respectively. Predicting high potential targets for high-priced drilling, just based on using the binary map, could be very risky. Therefore, an innovative CBA data integration approach was employed to assign proper weights between 0 and 1 to the spatial proxies by calculating the importance of the presence of an exploration proxy in a cell using training (labeled) trenching geochemical data. A final continuous predictor map was generated and it successfully mapped the known outcropping porphyry center and its subsurface extension to the northeast as a high prospectivity class. This map also identified a narrow NE-trending high potential target (a few cells) of 200 m long in the southern part of the known porphyry center for drilling. [ABSTRACT FROM AUTHOR]

[Display omitted] • The alteration zone patterns have been identified based on the SWIR data at Demingding. • The relationship between Pos2200 and compositions of white mica has been demonstrated by EPMA and determined the subspecies in the ore and barren zone. • We predicted the center of hydrothermal/mineralization based on the spatial variations of the white mica SWIR scalars. The Demingding Cu–Mo deposit, found in the eastern Gangdese metallogenic belt in China, has a significant exploration potential. Detailed field studies coupled with short-wavelength infrared (SWIR) spectroscopy and electron probe micro analyses (EPMA) identified a total of 15 alteration minerals such as white mica group minerals, chlorite, kandite, and smectite groups. The study also discovered the spatial distribution of alteration zone patterns, including phyllic, propylitic, and intermediate argillic alterations. Furthermore, variations were observed in the Al-OH absorption position (Pos2200) of the white mica group with variable Al-Si-Fe-Mg content. Most of the white micas in the ore zone were muscovitic series, whereas the barren zone contained phengitic series micas. Some micas have undergone a transition to illite due to low-temperature alteration overprinting. The western part of the deposit exhibited lower Pos2200, higher SWIR-IC, and higher Dep2200 values, implying an intense phyllic alteration and higher paleotemperatures. These characteristics suggest that the area is in close proximity to the hydrothermal center and fluid channel. Therefore, it was identified as an exploratory target for buried copper ore bodies. The SWIR spectra of the white mica group can be used for exploration in other similar porphyry deposits. Under acidic conditions, shorter Pos2200 and higher SWIR-IC can be used as indicators for hydrothermal or mineralization centers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zircon U-Pb dating indicates that the Yunxian-Jinggu volcanic rocks were formed between 245 and 230 Ma. • Wenyu arc basalts originated from mantle metasomatized by fluids released from the subducted Paleo-Tethys slab. • Magmas of the Yunxian-Jinggu volcanic arc are less conducive to porphyry copper mineralization. Porphyry copper deposits are commonly associated with porphyries generated in arc environments. Assessing the contemporaneous arc volcanic rocks provides crucial insights into the potential for porphyry copper mineralization. The Triassic Yidun arc in the northern part of the Sanjiang orogen in southwest China, which formed in association with the subduction of the Paleo-Tethys Oceanic slab, hosts several porphyry copper deposits. However, the potential for porphyry copper mineralization in the Yunxian-Jinggu volcanic arc in the southern part of the Sanjiang orogen, which was also linked to the subduction of the Paleo-Tethys Oceanic slab, remains unclear. This study reports zircon U–Pb ages, trace element compositions and Hf isotopes, and whole-rock element compositions and Sr–Nd–Pb isotopes of the basaltic-andesitic-dacitic rocks in the Yunxian-Jinggu volcanic arc. Zircon SHRIMP U–Pb dating of the Wenyu basalts and andesites yielded ages of 244.3 ± 1.9 Ma and 242.5 ± 2.5 Ma, respectively. The basalts have arc geochemical affinities with ε Hf (t) values of 2.3 to 9.3, ε Nd (t) values of –0.6 to 0.2, and (87Sr/86Sr) i values of 0.7065 to 0.7068. They have high Ba concentrations (∼ 550 ppm), highly variable Ba/La ratios (0.01 to 0.10), and a narrow range of Th/Yb ratios (1.2 to 1.9). These characteristics suggest that the basalts were derived from mantle metasomatized by fluids likely released from the subducted Paleo-Tethys slab. The Wenyu andesites, with ε Hf (t) values range from 1.6 to 7.0, ε Nd (t) value of –0.4, and (87Sr/86Sr) i value of 0.7031, along with distinct Pb isotopes, were probably produced through basaltic magmas undergoing crustal fractional crystallization. The Minle dacites, sharing similar ε Hf (t) value (–1.6 to 10.7) but lower ε Nd (t) values (–3.1 to –4.9) compared to Wenyu volcanics, are interpreted as derived from partial melting of basaltic magmas with contamination from ancient crustal components. The zircon Eu/Eu* ratios (mostly < 0.4), zircon ΔFMQ value (–0.6 ± 1.1), and bulk-rock Sr/Y ratios (< 10.3) for the Yunxian-Jinggu volcanic rocks indicate that co-genetic intrusions, if present, would likely be less hydrous and less oxidized, making them less favorable for porphyry copper mineralization. [ABSTRACT FROM AUTHOR]

[Display omitted] • The newly identified granite porphyry dikes in the giant Dachang Sn ore field have emplacement ages of 35–33 Ma. • The Eocene dikes were formed due to lithospheric extension after the Indo-Asian collision. • The Eocene dikes are highly evolved S-type granitoids which present Sn mineralization potential. The world's second-largest Dachang Sn ore field in the southwest of China exhibits genetic connections to the Late Cretaceous highly evolved S-type granitoids (93–91 Ma). In this study, we report the newly identified Eocene granite porphyry dikes with zircon U-Pb ages of 35–33 Ma at the Gaofeng Sn deposit from the Dachang ore field. The petrogenesis and mineralization potential are also constrained by employing whole-rock and zircon geochemical data. These Eocene dikes coincide with the emplacements of granitoids (35–30 Ma) along the Ailaoshan–Red River fault and its neighboring regions, indicating that they could be related to a similar lithospheric extension setting after the Indo-Asian collision. However, unlike those of the latter granitoids (35–30 Ma), which are grouped into I-type granites, the high-silica granite porphyry dikes show elevated ASI values (1.32–1.38) with high P 2 O 5 (0.41–0.44 wt%) and normative-CIPW corundum (4.15–4.71 wt%) contents and could be classified as S-type granites. The strongly negative whole-rock Sr, Ba, and Eu anomalies signify separation of plagioclase and K-feldspar during magma crystallization, which is also confirmed by the zircon trace elements compositions. The Gaofeng Eocene granite porphyry dikes have a high initial zircon T ti-zr of 855 ℃, high Ba/Pb ratios (11.5–16.8), and low Pb contents (7.56–9.98 ppm) with low zircon ε Hf (t) values (−7.4 to −0.6), hinting at the dehydration melting of biotite from the metasedimentary basement. Additionally, the dikes are characterized by low oxygen fugacity (zircon Ce/Ce* <70; ΔFMQ from −6.0 to +0.6 with an average of −2.0) and show evidence of magmatic-hydrothermal interaction (whole-rock Nb/Ta < 5), in line with those of the Dachang Late Cretaceous fertile granites, suggestive of Sn mineralization potential. Therefore, it is recommended that attention should be paid to the Eocene granite porphyry dikes during future prospecting. [ABSTRACT FROM AUTHOR]

[Display omitted] • A porphyry-epithermal Au system is developed in the Songshunangou district. • The Songshunangou porphyry-epithermal Au system formed in the Early Paleozoic. • The Songshunangou porphyry-epithermal Au system formed in a magmatic arc setting. The Songshunangou district is located in the central part of the North Qilian orogenic belt and hosts both the Eastern and Western deposits. The Western deposit is a porphyry-Au deposit, characterized by concentrated high-grade Au mineralization within a quartz-dioritic porphyry and occurs along the contact to basaltic andesite. Alteration is concentric with potassic alteration associated with high-grade Au mineralization in the core zone, while surrounding propylitic alteration is associated with an only lower-grade Au mineralization. Barren sericite-chlorite alteration is restricted to shallow zones above or partially overprinted the potassic alteration. Mineralization, including chalcopyrite, bornite, pyrite, magnetite, native gold with minor galena, sphalerite, hematite, and covellite, is observed as quartz-sulfide stockworks and fine-grained disseminations in different alteration zones. LA-ICP-MS zircon U–Pb dating of samples from the ore-bearing quartz-dioritic porphyry, the post-mineralization dioritic porphyry and the granodioritic porphyry in the Western deposit yield mean 206Pb/238U ages of 456.3 ± 2.0 Ma to 454.9 ± 2.4 Ma, and 449.5 ± 4.5 Ma to 448.3 ± 1.4 Ma, respectively. Pyrite from quartz – chalcopyrite – bornite veinlets in the Western deposit yields a Re-Os isochron age of 454.6 ± 3.7 Ma. In the Eastern deposit, which is an intermediate-sulfidation epithermal deposit hosted in basaltic andesite, sericite-chlorite alteration is associated with the mineralization. The mineralization is predominantly found within veins and disseminated, primarily composed of galena, sphalerite, native gold, tetrahedrite, and minor chalcopyrite, pyrite, and covellite. The alteration mineral assemblage comprises sericite, chlorite, Mn-calcite, quartz, calcite, and minor epidote. A Mn-calcite – quartz – polymetallic vein from the Eastern deposit yields a calcite Sm-Nd isochron age of 453.2 ± 5.8 Ma, suggesting that intermediate-sulfidation mineralization was coeval with the emplacement of the ore-bearing quartz-dioritic porphyry and the porphyry mineralization in the Western deposit. Based on these geologic features and geochronological data, we conclude that an early Paleozoic porphyry-epithermal Au system developed in the Songshunangou district, which formed in an arc setting associated with the northward subduction of the North Qilian Ocean beneath the North Qilian orogenic belt. The occurrence of an early Paleozoic porphyry-epithermal Au system in the North Qilian orogenic belt provides new insights for regional mineral exploration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Late Triassic Xuejiping porphyries originated from mantle enriched by slab-melts and fluids. • Hongshan–Hongniu porphyry formed in late Cretaceous and the adakitic features were inherited from magmatic source. • Hongshan–Hongniu porphyry originated from the late Triassic juvenile crust, as well as a minor component of crystalline basement. • Lithospheric cycle of ore-forming ingredients caused recurrent 'flare-ups' of PCDs in a region. The porphyry Cu deposits with distinct mineralisation ages frequently occur as recurrent 'flare-ups' in a narrow region; however, the reasons controlling their occurrence are still debated. The eastern Yidun Arc in eastern Tibet produced a cluster of porphyry Cu deposits of the late Triassic and late Cretaceous ages, making it the ideal location for conducting this research. As a result, we use the late Triassic Xuejiping Cu–(Au) and late Cretaceous Hongshan–Hongniu Cu–Mo deposits as research objects, compiling new and published geochronological, elemental, and Sr–Nd–Hf isotopic data from their ore-forming porphyries to shed light on the above issue. The zircon U–Pb ages of the Xuejiping and Hongshan–Hongniu porphyries are 217.8 – 217.9 Ma and 78.7 Ma, respectively, and display adakitic characteristics. The Xuejiping porphyries present enriched Sr–Nd–Hf isotopes (0.70529 – 0.70590, −3.30 – −1.09, 0.40 – 2.20, respectively), low (Gd/Yb) N (2.24 – 3.20) and Nb/Ta (12.8 – 15.9) ratios, relatively high Nb (14.9 – 20.0 ppm) and Zr/Sm (23.4 – 41.5) values, indicating their origin in the partial melting of enriched mantle that is metasomatised by slab-melts and fluids in subduction zone. Furthermore, the Hongshan–Hongniu porphyry is adakitic, like the late Triassic igneous rocks in this area. Its Sr–Nd–Hf isotopes (0.69873 – 0.70996, −10.7 – −6.72, −14.9 – −0.50, respectively) are close to the isotopic evolution line of the late Triassic Xuejiping intrusions and show a trend towards the regional crystalline basement, which signify that the Hongshan–Hongniu porphyry mainly originated from the late Triassic juvenile crust, with some contributions from crystalline basement. One highly fractionated sample (i.e. HZK17-11-76) has extremely evolved Sr–Nd isotopes (0.70996 and −10.7, respectively), indicative of assimilation of sedimentary rocks. The new genetic models of the late Triassic and late Cretaceous porphyries in the Geza Arc show that the westward subduction of the Garzê–Litang oceanic crust in the late Triassic triggered the occurrence of the highly oxidised and Cu–S–H 2 O rich adakitic melts in the middle–lower crust, which evolved to amphibole cumulates and porphyry Cu–(Au) deposits (i.e. Xuejiping) in the upper crust. In the late Cretaceous, the extensional environment triggered the re-melting of late Triassic juvenile cumulates and Mo-rich crystalline basement, resulting in Cu–Mo–S–H 2 O-rich, highly oxidised magma. Through fractional crystallisation and assimilation of Mo-rich sedimentary rocks, the magma eventually transformed into Hongshan–Hongniu porphyry-(skarn) type Cu–Mo deposits. In summary, we conclude that the periodic recycling of the ore-forming ingredients on a lithospheric scale from slab subduction to post-subduction periods controls the recurrent 'flare-ups' of PCDs in this confined area. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magmas associated with post-collisional deposits and barren systems in the Gangdese belt both reached sulfide saturation and have comparable PGE and Cu concentrations at the early stage of differentiation. • The ore-forming magmas show highly variable Cu, Au and PGE trends after they reached fluid exsolution. • Assimilation and cannibalization of sulfides in the underlying mush zones by fluid-saturated ore-forming magmas result in the porphyry Cu deposits formation, which may be stimulated by regional extension. Production of Cu-rich melts via melting of sulfide-bearing lower crustal cumulates is thought to contribute to porphyry Cu formation in the post-collisional Gangdese belt (Tibet). We present new whole rock, including platinum group elements (PGE) data, for ore-causative granites (OCG), ore-related granites (ORG) and barren granites (BG) from the Gangdese belt. The OCG, ORG and BG show indistinguishable Cu, PGE and Cu/Ag behavior during differentiation down to ∼2 wt% MgO. These systematics, together with the occurrence of sulfides, demonstrate that the propensity for some Gangdese magmas to be ore-associated is unrelated to melting of sulfide-bearing cumulates or the relative timing of sulfide fractionation. The behavior of chalcophile and siderophile elements during differentiation of the OCG, ORG and BG diverges when melts evolve past 2–3 wt% MgO and exsolve H 2 O, S and Cl: the BG show a decrease in Cu, whereas the OCG and ORG show highly variable Cu, Au, and PGE trends. Because S degassing causes melts to become sulfur undersaturated and because Cu is highly soluble in Cl-rich fluids, any sulfides in contact with the melt or magmatic fluids following volatile exsolution would dissolve. Continual injection, cooling and ascent of magmas through the Gangdese crust is expected to have resulted in the development of regions of crystal-rich partially molten crust beneath the intrusive granites. We suggest that prior to porphyry mineralization, extension and erosion caused exhumation of these long-lived sulfide-bearing mush zones. This exhumation may have caused a change in magmatism style from volatile exsolution after the melts transited sulfide-bearing mushes (i.e., the BG), to volatile exsolution during magma transit through sulfide-bearing mushes (i.e., the OCG). We suggest that only the magmas and that exsolved fluids during their ascent through sulfide-bearing mushes were able to assimilate sufficient Cu-rich sulfides to fuel the formation of porphyry Cu deposits in the region. [ABSTRACT FROM AUTHOR]

[Display omitted] • Molybdenite–W(–Cu) mineralization is related to Late Cretaceous porphyries. • Porphyries experienced fractional crystallization and late-magmatic alteration. • External fluids are documented by anomalously high δ7Li and low δ11B values. • External fluids interacted with porphyries and redistributed W, Mo, Cu, and Sn. The Relin Mo–W (–Cu) deposit in the northern Sanjiang area is bound to a Late Cretaceous intracontinental porphyry showing variable alteration. Here we present whole-rock chemistry and Sr, Nd, Pb, Li, and B isotope data to constrain the sources of ore-magmas and to understand how magmatic-hydrothermal processes mobilize the ore elements and alter the magmatic rocks. Chemical variations indicate the ore-bearing porphyries reflect two processes: fractional crystallization and late-magmatic alteration. Fresh and weakly altered porphyries are metaluminous to weakly peraluminous, showing I-type affinity. Chemical variation among these rocks can be explained by fractional crystallization. Most of these rocks show narrow ranges of isotopic compositions with –8.6 to –6.6 for εNd 80 , 0.70660 to 0.71028 for 87Sr/86Sr 80 , and high 207Pb/204Pb 80 (15.57–15.66) and 208Pb/204Pb 80 (39.21–39.51) values at 206Pb/204Pb 80 values of 17.37 to 18.96. The chemical and isotopic compositions of these rocks indicate that the porphyries represent mantle melts that mixed with partial melts from the Paleoproterozoic crust. Fresh and weakly altered porphyries have uniform δ7Li (–2.3 to 1.5 ‰) and δ11B (–8.0 to –12.0 ‰). The strong sericite alteration of the porphyries resulted in the loss of Na 2 O and Sr (breakdown of feldspar) and the strong enrichment of the ore elements Cu, Mo, W, and Sn. Porphyries with varying degrees of alteration show large ranges of δ7Li (–6.0 ‰ to 11.4 ‰) and δ11B (–8.0 to –29.2 ‰). The anomalously high δ7Li and low δ11B values of the altered rocks indicate that the intrusions drove the flow of external fluids that altered the magmatic rocks and leached the ore elements W, Mo, Cu, and Sn from the porphyries and possibly the local wall rocks. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Ahadawa deposit is a newly discovered porphyry Cu–Mo system in the North Qaidam. • The Ahadawa formed by more than 25 Ma prolonged magmatic-hydrothermal activity. • The Late Triassic fertile magmas initially had high water and high oxygen fugacity. • Plagioclase-dominated fractionation occurred with magma evolution. Ongoing exploration in the North Qaidam, Northern Qinghai-Tibet Plateau, NW China, has led to the identification of a porphyry Cu-Mo system centered on Ahadawa. In this study, we conducted a detailed geochronological and geochemical study on porphyritic monzogranite from the Ahadawa deposit, which hosts the Cu-Mo mineralization. The weighted mean zircon U-Pb ages for three mineralized porphyritic monzogranite samples from different sites range from 218.8 ± 1.2 Ma (MSWD = 1.5) to 224.7 ± 1.6 Ma (MSWD = 1.8), and finally to 233.1 ± 0.9 Ma (MSWD = 1.4, n = 23). These results, combined with antecrystic grains as old as ∼ 245.7 Ma, collectively indicate more than 25 Ma multi-stage magmatic emplacement activity in the Ahadawa deposit. Corresponding to complex magma episodes, six studied molybdenite samples yielded variable Re-Os model ages ranging from 436.7 ± 6.6 to 232.6 ± 1.2 Ma, with the three youngest dates constraining a weighted mean Re-Os age of 234.0 ± 6.8 Ma. The 234 Ma mineralization age is consistent with the observed Late Triassic magmatism, whereas the Re-Os model ages of 436.7 to 245.7 Ma, if they remain robust through future investigation, may highlight a long-lived hydrothermal activity in the Ahadawa deposit. Whole-rock and zircon compositions indicate that the Late Triassic porphyries occurring at the surface display distinct geochemical features, with the early porphyritic monzogranite of 233.1 Ma characterized by much higher whole-rock Sr/Y, and zircon Eu/Eu* and Ce/Ce* than the younger (218.8 Ma and 224.7 Ma, respectively) porphyritic monzogranite. This suggests that the Late Triassic magmas were initially characterized by high water content and high oxidation state and the differences between the old and two younger groups might be related to plagioclase-dominated fractionation. The finding of the Ahadawa porphyry system highlights the need for ongoing exploration (especially in poorly studied remote areas) and systematically geochronological and geochemical studies to constrain the temporal and spatial evolution of mineralized episodes within a complex, protracted magmatic history. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zircon U-Pb dating constrains the chronological order of granitic rocks at Leimengou deposit. • The syn -ore granitoid originated from crustal rocks, mainly from the crust of Huaxiong Block. • The more evolved porphyritic K-granite exhibits a higher potential for Mo mineralization. • The Leimengou deposit formed under a transition setting from compression to extension. The Leimengou giant Mo deposit is a porphyry system in the northeastern Qinling Orogen along the southern margin of the North China Craton, comprising orebodies hosted mainly in a multiphase porphyritic granitic to monzonitic pluton emplaced in the Taihua Supergroup. Zircons from the syn -ore porphyritic monzogranite (PMG) and the porphyritic K-feldspar granite (PKG) yielded U − Pb ages of 131.3 ± 1.0 Ma and 130.6 ± 0.9 Ma, respectively. The post-ore, quartz monzonite porphyry (QMP), has a weighted mean 206Pb/238U age of 124.6 ± 1.0 Ma (n = 14, 1σ, MSWD = 0.13). These ages constrain the Leimengou porphyry system to have formed between 132 and 124 Ma. The PMG and PKG have similar geochemical characteristics, i.e., high-K calc-alkaline affinity, negative ε Hf(t) values of − 25.1 to − 22.0 and − 25.1 to − 19.2, and T DM2 ages of 2.77–2.57 Ga and 2.76–2.40 Ga, respectively. The PKG has lower concentrations for Sr, Ba, and negative anomalies of δEu, and also has higher total REE values compared to the PMG. These anomalies are interpreted to reflect fractional crystallization involving plagioclase and biotite. The characteristics of the PKG support its derivation from an evolved magma, which likely facilitated the enrichment of Mo. Additionally, the Hf isotope data suggest that the Leimengou porphyry system had a composite source, with inputs from the North Qinling Accretion Belt, the North China Craton, and the mantle. Compared to the syn -ore PMG, the post-ore QMP exhibits lower (La/Yb) N ratios of 20.5–22.8, higher zircon ε Hf(t) values of − 19.7 to − 9.0, and younger T DM2 ages of 2.42–1.75 Ga. This suggests that the Leimengou porphyry Mo system formed during thinning of an overthickened orogenic crust during the tectonic transition from collisional compression to post-collisional extension. The productive intrusions at Leimengou and other porphyry Mo deposits of Dabie-type have average Nb/Zr ratios that are typically below 1. Moreover, the Rb/Sr ratios range from 0.1 to 1, further distinguishing these intrusions from the intrusions associated with Climax- and Endako-type Mo deposits. [ABSTRACT FROM AUTHOR]

[Display omitted] • Five types of tourmaline have been identified in the Donggebei Mo deposit. • The tourmalines belong to alkali group, changing from shorl to dravite. • The δ11B values imply magmatic-hydrothermal fluid origin. • Chemical variations of tourmaline trace the ore-forming processes. Tourmaline is a chemically and mechanically stable mineral that commonly occurs in hydrothermal mineral systems, and has been used to trace the mineralization processes of many genetic types of ore deposits. Here we apply tourmaline chemistry and isotopic composition to trace the genesis of a porphyry Mo system for the first time. Tourmaline is widespread in the Donggebi Mo deposit in East Tianshan, NW China, where it occurs in five distinct associations: type PG disseminated in the porphyritic granite, TS as hydrothermal tourmalite in the country rocks (strata), V1 in quartz-molybdenite vein, V2 in quartz-polymetallic sulfide vein, and V3 quartz-calcite-fluorite vein. All the tourmaline types belong to the alkali group, with the V3 being schorl and the other types being dravite and schorl. The PG-type tourmalines partly inherit the features of the porphyritic granite, and are rich in F, Na, Al and Sc, and poor in Fe, Mg, Ca, Sr, Ba, Pb, V and Mo compared to the other types. They have low Fe3+ concentrations and low Fe3+/(Fe3++Fe2+) ratios, suggesting a reducing fluid system. They also display weaker Eu-depletion (with an average (Eu/Eu*) N value of 0.96) than the porphyritic granite, and are considered to be the products of interaction of the reducing fluids and the granites. The average (Eu/Eu*) N values of tourmalines decrease from 6.66 of type V1, 5.65 of type V2, to 4.80 of type V3, indicating that the fluids became progressively less reducing along with sulfide precipitation. The δ11B values of the tourmalines range between −15.9 ‰ and −12.5 ‰, resembling those of S-type granites or clastic sediment-sourced hydrothermal fluids. The tourmaline grains in our study do not display any remarkable δ11B variation from the cores to rims, indicating that the δ11B values of the fluids and their source were relatively constant. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reinterpretation of previous drill holes intercepting carbonate rocks of the Roberts Mountains autochthon can identify normal faults based on omissions in the expected stratigraphy. • Exposures of carbonate rocks are related to Mesozoic anticlines exhumed in the footwalls of normal faults. • Gold deposits hosted in the siliciclastic rocks of the Roberts Mountains allochthon could be the product of the Carlin-type ore fluid (e.g., Hilltop) or the product of coeval or younger surficial/basinal fluids remobilizing gold from elsewhere. This study integrates results from previous studies with new reconnaissance-scale mapping of rock types, structures, and hydrothermal alteration at Goat Ridge and Tenabo to provide a district-scale cross section and palinspastic restoration of an area in Nevada with high potential for Carlin-type mineralization in the footwall of a dismembered thrust fault. Reinterpretation of legacy drill data in light of recent advances in the understanding of Cenozoic normal faulting in the area with the expected stratigraphy of the Roberts Mountains autochthon allows for deciphering whether previous drill holes piercements of faults are the Roberts Mountains thrust or are tilted normal faults that down-dropped the deep-water siliciclastic rocks of Roberts Mountains allochthon onto the coeval carbonate rocks of the Roberts Mountains autochthon. A cross-sectional reconstruction shows that ∼11.1 km (120 %) of extension was accomplished along one set of faults that initiated at 60-70°and tilted 40°E. Previously underappreciated Mesozoic folds are present, which likely formed with horizontal fold hinges. Because of Cenozoic normal faulting and associated tilting, the hinge lines currently plunge at moderate angles and are offset as they step across each crosscutting fault. The anticlinal fold hinges produced the modern exposures of lower plate rocks in the range. The Eocene paleogeologic map that results from a plan-view structural restoration shows that the hinge lines of the original folds trended northwest-southeast in the southern half of the range but turned northward toward the northern end of the range. Mineralization in the range includes silver-dominated polymetallic veins/lodes, weak porphyry-type, Carlin-type, and siliciclastic-hosted gold deposits of uncertain origin. Porphyry-style and silver-dominated polymetallic vein mineralization is associated with ∼39–40 Ma granodiorites, with the silver-dominated polymetallic veins interpreted as the distal veins around weakly mineralized and/or deeply buried porphyry system(s), probably of the quartz monzonitic-granitic porphyry Mo-Cu subclass of porphyry molybdenum deposits. Crosscutting relationships demonstrate that at least one of "upper plate" gold deposits is Eocene, but a Miocene age cannot be ruled out for the other gold deposits. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two distinct geological ages of molybdenite are determined at Sanchakou. • Decreased temperature and f O2 contributed to porphyry-style ore formation. • High grade copper was likely attributed to overprinting mineralization event. • Identification of an old deformation-related porphyry Cu deposit in Xinjiang is helpful for guiding ore exploration. The Sanchakou Cu deposit is located in the eastern section of the Dananhu arc belt in Eastern Tianshan, Xinjiang, and recorded multiple magmatic-mineralization events. The porphyry-style mineralization period produced disseminated, sulfide-dominant veined, and patchy sulfides containing chalcopyrite ± bornite ± carrolite ± molybdenite (Mol-1), which was associated with magnetite ± biotite ± chlorite ± sericite alteration in a suite of quartz diorite intrusions. The overprinting mineralization period contributed to minor Cu and Mo mineralization, featured by later disseminated molybdenite (Mol-2), chalcopyrite, and widespread low-temperature (<280 °C) vein-type stellerite assemblages. Two distinct geological ages of molybdenite (including Mol-1 and Mol-2) from Sanchakou have been determined in this study. The old 187Re/187Os isochron age for euhedral Mol-1 represents the timing of original porphyry-style mineralization (386 ± 16 Ma), in agreement with LA-ICP-MS zircon U-Pb age of dark diorite dykes (390 ± 11 Ma). The young 187Re/187Os age for fine-grained Mol-2 is interpreted to be a maximum age of sulfide formation or remobilization (364 ± 15 Ma), most likely associated with the emplacement of Late Devonian gneissic granite intrusions. Fluid inclusion microthermometry, mineralogy, and physicochemical calculations for the porphyry-type mineralization period (including four stages) at Sanchakou suggest that earlier magmatic fluids have evolved from high T (310–460 °C), high log f O2 (−22 to − 26), and alkaline condition during stage I to low T, low log f O2 (−3 4), and acidic condition during stage II. The decrease of oxygen fugacity caused by abundant deposition of magnetite in stage I produced large-scale Cu and Mo precipitation. Stage II to IV fluids have gradually decreasing temperatures and salinities, due to involvement of meteoric water that also facilitates the ore deposition. This result is consistent with the evolution of O isotope compositions of the fluids (δ18O fluids = − 9.3 to 4.3), further implying the significance of fluid mixing instead of fluid boiling that caused ore deposition. Locally high-grade copper concentrations at Sanchakou are likely attributed to the overprinting modification event on the original ore bodies. All of these observations indicate that the Paleozoic Sanchakou ore-forming system is similar to other deformed porphyry Cu systems in the Central Asian orogenic belt (CAOB) and worldwide. The Cu mineralization and modification event at Sanchakou is coincident with the second peak productivity in CAOB. We further suggest that the Paleozoic diorite complex and stellerite alteration can be as a significant exploration target for porphyry-style Cu mineralization in the Eastern Tianshan. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chlorite, epidote, and apatite in five stages show different geochemical features. • Magmatic hydrothermal fluids played a remarkably crucial role during the overprinting period. • The mechanism of copper precipitation is distinct in different stages. Porphyry copper deposits can be deformed by subsequent magmatic-tectonic-metamorphic evolution, resulting in the remobilization of pre-existing ores and the consequent overprinting mineralization. This process might potentially increase the ore grade and/or resource. We focus on the Duobaoshan porphyry Cu (Mo) deposit, two periods were identified in this study, i.e., porphyry period (including Stage 1: potassic alteration; 2: propylitic alteration, and 3: chlorite-sericite alteration and porphyry mineralization) and overprinting period (including Stage 4–1: ductile–brittle deformation; Stage 4–2 and Stage 4–3: overprinting mineralization). Metal sulfide veins occur along the schist in Stage 4–2 and Stage 4–3, features that differ from the typical porphyry mineralization of Stage 3 (veinlets, stockworks, and dissemination). Here, we present in situ Sr isotope data for apatite and compositions of chlorite, epidote, and apatite to reveal the source and nature of fluids and mechanism of precipitation during overprinting mineralization. The in situ 87Sr/86Sr ratios of apatite from Stages 3, which range from 0.7030 to 0.7046, are slightly higher than those observed in the Ordovician granodiorite. Meanwhile, the Sr isotope ratios for apatite from Stages 4–2 and 4–3 are 07033–0.7040 and 0.7013–0.7045 respectively. These ratios broadly consistent with those of the surrounding Ordovician granodiorite and basaltic andesite, suggesting that the ore-forming fluids for all these stages originated from magmatic sources. Chlorite in Stage 4–2 has a higher Mn, Co, Ni, Zn content compared to chlorite in Stage 3, 4–3, whereas epidote and apatite in Stage 4–2 have higher Ca, Sr, Pb content compared to those in Stage 3, 4–3, implying that the fluids in Stage 4–2 underwent strongly water–rock reactions and extracted metal elements from surrounding rocks. Copper was only detected in Stage 4–3 chlorite (15.13–500.20 ppm) and epidote (7.91–19.29 ppm), indicating a high concentration of copper in the fluid, and due to the pre-existing magnetite dissolution, chlorite, epidote, and apatite in Stage 4–3 exhibit high V and Fe relative to other stages. Fluid mixing likely occurred during Stage 3, leading to the precipitation of copper. Strong water-reaction in Stage 4–2 produce changes in fluid natures that facilitate sulfide deposition during this stage. While in Stage 4–3, copper precipitation is controlled by a combination of rising pH and changing sulfur content and valence. Our study highlights that in the Duobaoshan deposit, late magmatic-hydrothermal fluids remobilized pre-existing ore bodies, and the copper precipitation mechanisms differed during the main copper mineralization events. [ABSTRACT FROM AUTHOR]

[Display omitted] • Investigation of Middle Devonian Evandale porphyry Cu-Mo (Au) deposits, southwestern New Brunswick, Canada. • Interpretation of Evandale igneous U-Pb ages compared with surrounding intrusions' age. • Petrogenetic analysis of this Devonian adakitic I-type granitic system, with slab failure. • Pb-Pb isotopic analysis of the origin of the Middle Devonian Evandale porphyry Cu-Mo (Au) deposits. • Amphibole and biotite compositional constraints on P-T of the porphyritic granite and locally porphyritic aplitic dyke. The 391.2 ± 3.2 Ma (U-Pb on zircon) Evandale Granodiorite of southwestern New Brunswick is quite a unique intrusive rock in the southern part of the northeastern Appalachians. This research examines the relationship between the porphyry Cu-Mo-(Au) and epithermal systems with Evandale Granodiorite and environs. This Middle Devonian multi-phase I-type granite intrudes along the northern boundary of the deformed Silurian sedimentary and mafic volcanic rocks of the Mascarene Basin. This granitoid is identified as an oxidized I-type system with adakitic geochemical signatures and associated porphyry Cu-Mo-(Au) mineralization, possibly linked to slab failure sourced from decompression melting of the lower crust caused by post-collisional uplift, similar to the Magaguadavic Granite to the southwest. The Evandale adakitic intrusion is divided into two phases that consist of (1) a calc-alkalic coarser phase ranging from medium- to coarse-grained, seriate to porphyritic granodiorite to monzogranite with metaluminous to peraluminous features, and (2) the later stage alkali-calcic fine-grained (to aplitic) locally porphyritic phase ranging from a monzogranite to syeno-granite with peraluminous characteristics. The primary mineralogy of the intrusive rocks consists of K-feldspar + albite + plagioclase + quartz + biotite + hornblende + apatite ± muscovite ± zircon, along with several alteration phases, such as biotite, chlorite, sericite, and calcite. Geochemical analyses (using INAA, ICP-MS, and XRF) indicate that both phases of the Evandale granodiorite show a high concentration of Cu (108 ppm) and Au (33 ppb) associated with the presence of pyrite, chalcopyrite, and arsenopyrite in the fine-grained dyke samples. Up to 6 ppm Mo was contained within the granitic phase, whereas lesser amounts of Mo were confined to the fine grained to aplite phases. Microprobe analyses of primary biotite as both phenocrysts and groundmass shows 0.55 avg. wt.% Cl and 0.21 avg. wt.% F, which are relatively concentrated compared to other high-grade porphyry deposits. Hydrothermally altered rocks, veins, and sulfides associated with the porphyritic suite result from buoyant magmatic-hydrothermal fluids from a deeper intrusion exsolving fluids (quenched porphyry related), depressurizing, and reacting with the host coarser grained granodiorite and even some of the dykes locally. Based on the geothermometry and geobarometry of amphibole (actinolite-magnesiohornblende), the crystallization temperature and pressure of the Evandale coarse-grained granite and aplite are 674–755 °C, 0.2–0.7 kbar (20–70 MPa) and 838 °C, 0.42–1.4 kbar (42–140 MPa), respectively. This is consistent with biotite formation at temperatures ranging from 670° to 760 °C, based on Ti-in-biotite thermometry. Also, zircon saturation temperatures of the earlier coarse-grained porphyritic granites and later fine-grained porphyry to aplitic dykes are 736 °C and 787 °C, respectively. Spatially and temporally associated gold deposits beside Evandale and within this region of southwestern New Brunswick suggests that these oxidized I-type intrusions are a potential source for distal, low sulfidation epithermal gold deposits in the region. [ABSTRACT FROM AUTHOR]

[Display omitted] • Kusongmuqieke Group had a higher contribution to skarn mineralization than granodiorite porphyry. • Skarn and porphyry mineralization were formed successively during Middle Devonian. • The proposed metallogenic model may assist in the exploration of similar deposits. The Saibo skarn–porphyry deposit, located in West Tianshan, NW China, is a large copper deposit discovered recently; however, information regarding the differences and connections between skarn and porphyry mineralization remains limited. Thus, this study aimed to investigate fluid inclusions (FIs), H–O–C–S–Pb isotopes, and U–Pb, and Re–Os geochronology to unravel the origin and evolution of the entire hydrothermal system. Skarn mineralization occurs as stratiform and lenticular in the contact zone between the granodiorite porphyry and Kusongmuqieke Group limestone. We identified four mineralization stages: prograde skarn stage (I S), retrograde skarn stage (II S), quartz–pyrrhotite–chalcopyrite stage (III S), and calcite–quartz–pyrite stage (IV S), and four types of FIs: CH 4 -rich (C-type), halite-bearing (S-type), vapor-rich (V-type), and liquid-rich (L-type) FIs. The homogenization temperatures (T h) of FIs from stages I S , III S , and IV S were 366–419, 271–315, and 174–235 °C, respectively, with salinities of 1.7–46.0, 2.2–9.6, and 4.5–7.7 wt% NaCl eqv., respectively. Porphyry mineralization occurs as veinlet-disseminated ores in the granodiorite porphyry. We identified three mineralization stages: quartz–molybdenite–pyrite stage (I P), quartz–chalcopyrite–pyrite stage (II P), and calcite–quartz–galena stage (III P). Unlike skarn mineralization, only the S-, V-, and L-type FIs were identified, with T h of 332–379, 263–315, and 169–233 °C from stages I P , II P , and III P , respectively, and salinities of 1.9–42.3, 2.2–9.6, and 4.2–6.9 wt% NaCl eqv., respectively. The H–O isotope data indicate that the ore-forming fluids were initially derived from magmatic water and gradually diluted by meteoric water during fluid migration. According to C isotope data and the presence of C-type FIs, fluids from skarn mineralization contained more organic carbon than those from porphyry mineralization. The S–Pb isotope data of sulfides suggest that ore-forming materials are derived from both granodiorite porphyry and the Kusongmuqieke Group, although the latter contributed more to skarn mineralization. Pyrites from porphyry mineralization yielded a Re–Os isochron age of 376.0 ± 7.9 Ma, which was slightly younger than the chalcopyrite Re–Os ages of skarn mineralization (>379 Ma). The granodiorite porphyry, which is considered the ore-causative intrusion, yielded a U–Pb age of 380.8 ± 1.8 Ma. Our results indicate that two styles of mineralization were formed successively at different spatial locations during the emplacement of the granodiorite porphyry in a southward subduction setting of the North Tianshan Ocean. The proposed metallogenic model provides a better understanding of the Saibo skarn–porphyry metallogenic system and is expected to assist in the exploration of similar deposits in the West Tianshan orogenic belt. [ABSTRACT FROM AUTHOR]

[Display omitted] • We report the discovery of a Molybdenum (Mo) porphyry deposit at Shuvuutai, central-east Mongolian. • Molybdenum mineralization spatially and genetically related to Early Permian multi-phase porphyry intrusions. • Ore-forming fluids were initially magmatic and later hydrothermal mineralization evolved with four main stages. • We suggest a new strategy for exploration for Mo and related porphyry deposits in Mongolia and China. We document the newly discovered Shuvuutai Molybdenum (Mo) porphyry deposit located in the central-east Mongolian volcanic/-plutonic belt of the southern Altaids. The deposit is characterized by quartz vein- and veinlet-disseminated-type Mo ore bodies mainly hosted in a Late Permian-Early Triassic granitic intrusion. In this study, we provide a detailed study that integrates detailed geology with petrographic, mineralogic, geochemical, and geochronologic date to determine the tectonic setting of the deposit. Fluid inclusion analysis is used to reconstruct the fluid evolution history of the Shuvuutai Mo mineralization system and to understand the origin of the deposit. The ore bodies occur mainly as veins, lenses, and pods in positions from inner intrusions through contact zones to the host rocks distal to causative intrusions. The host rocks are variable in lithology, including granites, porphyries, volcanic breccias and tuffs, and sedimentary rocks. Outward from ore bodies to host rocks, the wall rock alteration is zoned from potassic (K-feldspar-quartz-mica), through phyllic (quartz-sericite-chlorite-epidote), to propylitic or argillic alterations. Two samples from porphyry stock intrusions at Shuvuutai were selected for U–Pb zircon geochronology and trace element composition studies, including the ore-hosting monzodiorite porphyry and quartz syenite porphyry. Our new ages are consistent with, or slightly postdate published zircon U-Pb ages of early phase of monzodiorite porphyry (268–232 Ma) and the main phase of quartz syenite porphyry (251.6 ± 1.7 Ma). Hydrothermal mineralization generally includes four stages, from early to late, represented by (1) potassic feldspar-quartz veins or veinlets, (2) quartz-molybdenite stockworks, (3) quartz-sulfide stockworks, and (4) quartz ± carbonate veins or veinlets. The ore-forming fluids were initially magmatic in origin and show high-temperature and high-salinity, containing daughter mineral and CO 2 -bearing fluid inclusions; and eventually evolved to low-temperature, low-pressure, low-salinity and CO 2 -poor meteoric water. S isotopic compositions of sulfides from the Shuvuutai Mo porphyry deposit indicate that the source of the ore-forming material was derived from the felsic magma. The Central-Eastern Mongolian volcanic-plutonic belt continues from Mongolia into northeast China, where similar Mo deposits are not yet recognized, suggesting that a new exploration strategy, based on the characteristics and history of the Shuvuutai discovery, is needed for the Chinese segment of the Altaids. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plurigaussian simulation is used for geological modeling of a porphyry deposit. • Local proportions of geological domains are used to model non-stationarity. • Our proposal outperforms simplistic approaches that ignore local domain proportions. In mineral resources extraction projects, the morphology of geological domains that make up the ore types in a mineral deposit is essential for mine and plant planning and design. Modeling the layout of these domains and quantifying the uncertainty associated with such a layout can be performed via geostatistical simulation in order to provide multiple geological outcomes that are equally likely to occur. This work focuses on showing how plurigaussian simulation can help to model ore type domains exhibiting spatially varying probabilities of occurrence, through an application to a porphyry copper deposit in northwestern Iran. The results demonstrate the advantage of incorporating spatial variations of the domain proportions, in accordance with the geological interpretation of the deposit, to obtain geologically consistent and realistic outcomes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The mineralization at Beimulang might be related to the Miocene monzogranite porphyry. • The monzogranite and granite porphyries at Beimulang were derived from the subduction- modified juvenile lower crust. • The mineralization process at Beimulang was influenced by hydrous high-Mg dioritic magmas. • The granite porphyry's low mineralization potential stems from its limited juvenile melt input and lack of high-Mg dioritic magmas. The Beimulang deposit, a newly discovered large porphyry copper deposit, containing 1.3 Mt @ 0.38% Cu, prominently features mineralized orebodies and hydrothermal alteration in the monzogranite porphyry. Zircon U-Pb dating reveals ages of 14.4–14.0 Ma for the monzogranite porphyry and 11.2–11.0 Ma for the granite porphyry. A consistent Re-Os age of 14.1 ± 0.4 Ma from molybdenite suggests a possible link between mineralization and the monzogranite porphyry. The Beimulang Miocene porphyries are rich in SiO 2 (70.01–72.81 wt%) and Sr (217–864 ppm) and have high Sr/Y ratios (26–139), which were originated from partial melting of the subduction-modified Tibetan juvenile lower crust. The Beimulang Miocene porphyries show high log w(Fe 2 O 3 /FeO) values (>0) in whole rock and high δ Eu values (mostly > 0.3), high Δ FMQ (4.32–6.43) in zircons, suggesting a high oxidation state. The Beimulang Miocene porphyries show high V/Sc ratios in whole rock and high 10,000 × (δ Eu)/Y, high (Ce/Nd)/Y, low Dy/Yb ratios (i.e., mostly > 13, > 4, > 0.02 and < 0.3, respectively) in zircons, indicating they are notably hydrated. The granite porphyry has lower ε Nd (t) (0.70849 – 0.70996) values and higher (87Sr/86Sr) i (-9.3 – -7.8) in whole rock, lower ε Hf (t) (-5.25 – -2.70) and higher U/Yb (6.0–18.3), δ18O (6.42–7.57‰) in zircon than the monzogranite porphyry (ε Nd (t) = -5.52 – -4.45; (87Sr/86Sr) i = 0.70744–0.70818; ε Hf (t) = -3.24 – -0.92; U/Yb = 2.62–8.96; δ18O = 6.10–7.53‰), indicating that the granite porphyry contains fewer juvenile materials compared to the monzogranite porphyry. The high-Mg dioritic rocks in the Beimulang-Zhunuo area reveal significant correlations with monzogranite porphyry rather than granite porphyry in terms of Sr, Sr/Y, Dy/Yb, δEu and SiO 2 contents. Taking into account the contemporaneous presence of high-Mg dioritic rocks with the monzogranite porphyry, which are not contemporaneous with the granite porphyry at Beimulang, it can be inferred that these diorite magmas played a significant role in forming the Miocene monzogranite porphyry rather than granite porphyry. Accordingly, the low fertility of the granite porphyry is possibly due to the limited contribution of juvenile melts and lack of the dioritic magmas. [ABSTRACT FROM AUTHOR]

[Display omitted] • In this study, we applied the measured spectrum of rock samples collected at the Pulang porphyry copper deposit for mapping alteration. • The Chinese ZY1-02D satellite remote sensing data were utilized to map serisite, chlorite and epidote minerals successfully. • Six new brownfield exploration target zones were delineated in Pulang porphyry copper deposit. Alteration minerals are important prospecting indicators, and multispectral and hyperspectral remote sensing technologies are important prospecting tools. Multispectral remote sensing data such as ASTER have been widely used for extracting alteration mineral information. The dataset is easy to access, cost-effective to use, and rich in rock and ore spectrum information. Recently, the use of alteration mineral identification technology and hyperspectral satellite data for fine prospecting has become feasible in China, considering the development of hyperspectral remote sensing technology, especially the launch of the ZY1-02D satellite in China. Pulang porphyry copper deposit, Southwest China, is a largescale, explored deposit with unclear peripheral prospecting. Therefore, principal component analysis (PCA) and mixed tuned matched filtering (MTMF) methods were used in this study to extract the mineralized alteration minerals of the Pulang porphyry copper deposit area from the ASTER multispectral data and ZY1-02D hyperspectral data. Then, Al-OH and Fe-Mg-OH alteration information was obtained from the ASTER data using the PCA method. Meanwhile, sericite, chlorite, and epidote alteration information was extracted using the MTMF method and ASTER data. With the ZY1-02D data, the alterations of sericite, chlorite, and epidote were extracted by the PCA and MTMF methods. A field verification showed that the overall accuracy of the ASTER-based alteration extraction was up to 0.57, and the overall accuracy of the ZY1-02D-based alteration extraction was up to 0.88. And circled six favorable areas of copper deposit based on alteration mapping. Therefore, the ZY1-02D data can be regarded as a reliable and promising tool for delineating potential prospecting areas according to the mapping of hydrothermal alteration information, which can be explored further in the prospecting field in the future. The eastern and northern parts of the first mining area should be further explored for potential prospecting. [ABSTRACT FROM AUTHOR]

• The vein quartz has early CL-bright Q1 and late CL-dark Q2 generations. • In situ analysis reveals obvious difference in oxygen isotopes between Q1 and Q2. • Molybdenite precipitated coeval with Q2, but later than Q1. • Formation of Q2 resulted from a significant input of meteoric water. • Fluid cooling by incursion of meteoric water caused Mo precipitation. There has been a long-term debate about the timing of the incursion of meteoric water into porphyry systems and whether it plays an important role in ore precipitation. To evaluate the role of meteoric water in the mineralization in porphyry Mo deposits, typical hydrothermal veins of different stages from the Chalukou giant porphyry Mo deposit are selected for combined scanning electron microscope cathodoluminescence (SEM-CL), fluid inclusion microthermometry and high-resolution secondary ion mass spectroscopy (SIMS) oxygen isotope analyses. Multiple generations of quartz are identified in almost all of the veins. The barren quartz veins and quartz-magnetite veins of the early Mo mineralization stage are dominated by granular CL-bright quartz (EMQ1), which usually shows dissolution and re-deposition textures and are overprinted by CL-dark quartz (EMQ2)-filled healed fractures. The molybdenite precipitation in the quartz-molybdenite veins of the main Mo mineralization stage is synchronous with small volumes (<15%) of CL-dark quartz (MMQ2) and postdates the large volume (>85%) of CL-bright quartz (MMQ1). Similar to the quartz-molybdenite veins, the precipitation of pyrite in the quartz-pyrite veins during the transitional stage and sphalerite in the quartz-sphalerite-pyrite veins during the Zn-Pb mineralization stage are also directly associated with CL-dark quartz (TSQ2, ZPQ2). The SIMS oxygen isotopic values of EMQ1 and MMQ1 fall into the range of 5.42–9.79‰ with calculated equilibrium fluid compositions of 2.07–6.45‰, indicating a magma-dominated fluid composition, whereas MMQ2, TSQ2 and ZPQ2 have very low oxygen isotopic values from −4.68 to 4.29‰ with corresponding fluid compositions of −13.64 to −5.94‰, implying that the fluid formed by the mixing of magmatic water and a large proportion of meteoric water. The contrasting SEM-CL features and oxygen isotopic compositions of the two generations of quartz in the quartz-molybdenite veins demonstrate that the incursion of meteoric water into the hydrothermal system occurred earlier than the molybdenite precipitation. Based on these results and the crosscutting relationships and spatial distribution of the veins, we reconstructed the quartz evolutionary sequence during the vein development process. After the early precipitation of barren quartz, the reduction in fluid pressure from lithostatic to hydrostatic conditions allowed the incursion of convecting cool meteoric water into the relatively hot hydrothermal system, and the temperature of the evolved Mo-rich fluid decreased rapidly from >500 °C to <400 °C, leading to concentrated molybdenite precipitation with small volumes of quartz. Fluid cooling resulting from the incursion of meteoric water may have played a greater role in the metal precipitation in the Chalukou Mo deposit than wallrock interactions and fluid boiling. Moreover, this process may have also occurred in other porphyry Mo deposits. [ABSTRACT FROM AUTHOR]

• Ages of Cu-Mo polymetallic deposits and the granodiorites (porphyries) in the Chizhou region are simultaneous; • The granodiorite (porphyry) are a high-K calc-alkaline I-type granodiorite; • The granodiorites formed from a mixed magma; • The formation of Cu-Mo polymetallic deposits depends on slab-derived Cl-enriched fluids, an oxidizing mixed source. The Cu-Mo polymetallic deposits are widespread in the Chizhou region, the Middle and Lower Yangtze River metallogenic belt, eastern China, but the formation of Cu-Mo polymetallic deposits remains unclear. Geochronological, geochemical and Sr-Nd-Hf isotopic compositions of the Cu-Mo polymetallic deposits in the Chizhou region are systemically investigated to reveal the formation of Cu-Mo polymetallic deposits and petrogenesis of the granodiorite (porphyry). The geochronological dating results show the formation ages of Cu-Mo polymetallic deposits (molybdenite Re-Os age, 151–148 Ma) and the granodiorites (porphyries) (zircon U-Pb age, 150–146 Ma) in the Chizhou region are simultaneous (within error). The Chizhou granodiorites (porphyries) (SiO 2 = 62.9–65.7 wt%) are high-K calc-alkaline peraluminous I-type granodiorites. They have high Mg# (mainly >40) values and low Na 2 O (<4.3 wt%) contents, negative whole-rock ε Nd (t) (−5.83 to −5.71) and zircon ε Hf (t) (−12.7 to −3.03) values, high apatite Cl contents (>0.2 wt%), and high log fO 2 values (−28.3 to −6.22). The distinctly chemical and isotopic compositions indicate that the Chizhou granodiorites formed from metasomatized mantle-derived magmas mixing with Neoproterozoic crustal components. The results indicate that the formation of the Cu-Mo polymetallic deposits in the Chizhou region may depend on the slab-derived Cl-enriched fluids, an oxidizing environment and a mantle-crust mixed source. [ABSTRACT FROM AUTHOR]

• The Wangpingxigou Pb-Zn deposit is a distal system to the Donggou porphyry Mo deposit. • Xiong'er Group may be the main sulfur source for the Donggou and Wangpingxigou deposits. • The establishment of Mo-Pb-Zn metallogenic stystem provides important clues on further prospecting. The southern margin of the North China Craton (NCC) hosts many world-class porphyry Mo and vein-type Pb-Zn ± Ag deposits, forming an important polymetallic metallogenic belt in China, even over the world. Although the Mo and Pb-Zn ± Ag mineralization are temporarily and spatially associated with each other, their possible genetic links are still unclear. To delineate the relationships between the two types of ore mineralization, we carried out in-situ geochemical and S-Pb isotopic analyses on sulfides from the two spatially associated deposits, i.e., the Wangpingxigou Pb-Zn and Donggou porphyry Mo deposits in the ore district. Based on field and microscopic observations on the crosscutting relationships of various veins and paragenetic relationships of various hydrothermal minerals, three (I–III) and four (I–IV) stages of hydrothermal veins have been identified in the Wangpingxigou and Donggou deposits, respectively. Pyrite grains from stage II of the Wangpingxigou deposit have high Co/Ni ratios (mostly > 1) and Au and As contents similar to those of typical epithermal systems. Moreover, sulfides from this deposit have in-situ 206Pb/204Pb (17.345–17.417), 207Pb/204Pb (15.454–15.514), and 208Pb/204Pb (38.138–38.364) ratios similar to those of sulfides from the Donggou deposit, indicating that the two deposits were relevant to a common source. The concentrations of many elements (i.e. Pb, Ag, Sn, Zn, Sb, Mn, Au and As) in pyrite decrease gradually from the stage II of the Wangpingxigou deposit to the stage II of the Donggou deposit, consistent with metal zonation typically observed in porphyry related metallogenic systems. Further considering similar ages of the two deposits, we propose that the Wangpingxigou Pb-Zn deposit is likely distal to the Donggou porphyry Mo system. The range of δ34S values of pyrites (7.63–8.76‰) from the stage II in the Donggou deposit is similar to those of the ancient strata (Xiong'er Group) (7.31–8.17‰) in the ore district, indicating that the sulfur in ore-forming fluids may be mainly derived from the ancient strata. However, the δ34S values (9.20–9.70‰) of Stage III sulfides in the Donggou deposit are higher than those of stage II sulfides in the Donggou deposit and stage II sulfides in the Wangpingxigou deposit (7.34–9.29‰). The different sulfur isotopic compositions may be related to varied physicochemical conditions of the ore-forming fluids. Confirmation of a Mo-Pb-Zn metallogenic system in the region provides important clues on further prospecting of Mo and Pb-Zn resources in the southern margin of the North China Craton. [ABSTRACT FROM AUTHOR]

• A Late Jurassic porphyry Cu-Mo deposit in the Erguna Block is reported. • Ore-bearing rocks were derived from the partial melting of the oceanic slab. • Petrogenesis of ore-related rocks related to a flat-slab subduction. The genesis of igneous rocks associated with the newly discovered Xiaokele porphyry Cu-Mo deposit, located in the eastern Erguna Block, NE China, can give insights into the regional geodynamic evolution during the Late Mesozoic. Several ore-bodies have been identified in a granodiorite porphyry stock, which intruded the rhyolite and was subsequently intruded by diorite porphyry and granite porphyry. The U–Pb ages of zircons from rhyolite, mineralized granodiorite porphyry, diorite porphyry and granite porphyry associated with the Xiaokele deposit are 152.5 ± 1.7, 150.0 ± 1.6, 147.9 ± 1.3, and 123.2 ± 1.7 Ma, respectively. The rhyolite and granite porphyry have high SiO 2 and low MgO, Cr, Co, and Ni contents. Their isotopic data show negative ε Nd (t) values of −4.76 to −0.87, initial 87Sr/86Sr ratios of 0.7066 to 0.7134 and positive zircon ε Hf (t) values of 0.33–5.56, indicating that they were derived from a basaltic lower continental crust. The mineralized granodiorite porphyry is characterized by high Sr/Y values and low Y (3.7–8.0) contents, showing adakite affinity. The low K 2 O/Na 2 O (0.51–0.7) ratios, high CaO contents, weakly negative ε Nd (t) (−1.17 to −0.27), and low zircon ε Hf (t) (1.49–5.4) values from the adakitic samples indicate that they were derived from the partial melting of an altered oceanic slab together with assimilation of mantle peridotite and crustal materials. The 148 Ma diorite porphyry has high Mg# (51–58), weakly negative and positive ε Nd (t) (−0.09 to 0.01) values, and lower (87Sr/86Sr) i (0.7055–0.7057) ratios, suggesting an enriched mantle wedge source. Considering the late Mesozoic regional tectonic evolution of the Erguna Block and adjacent area, we propose that the formation of the Xiaokele deposit is linked to the southward flat-slab subduction of the Mongol–Okhotsk oceanic plate during the Later Jurassic-Early Cretaceous. [ABSTRACT FROM AUTHOR]

• Ore geology, distribution, magmatic affinity, and relations to porphyry, high-sulfidation, and low-sulfidation deposits of intermediate sulfidation epithermal (IS) deposits are reviewed. • Deep and slow fluids exsolving is favorable for the occurrence of IS deposits. • An empirical subclassification (NC-type IS in neutral-compressive settings and E-type IS in extensional settings) of IS deposits is proposed. • The subtypes of IS are mainly controlled by the source of parental magma. Intermediate sulfidation (IS) veins is one of the subtypes of epithermal deposits formed in subduction-related arc settings or post-collisional orogenic belts. The economic and scientific significance of IS deposits has been highlighting importance in Ag-Au-Pb-Zn exploration and study of porphyry-epithermal systems. This epithermal clan of deposits typically have a close relationship with andesitic-dacitic volcanic-subvolcanic rocks, and formed at a depth of ∼0.3 to as much as 1 + km. IS deposits are typically related to oxidized calcic to calc-alkaline magmatism. Fluid homogenization temperatures and salinities range between 150 and 350 °C, and 0 and 23 wt% NaCl equivalent, respectively. The O and H isotope compositions are consistent with a mixture of magmatic and meteoric water, with an increase in meteoric diluent as the hydrothermal system wanes. Most of the IS deposits in the world, particularly those in Circum-Pacific metallogenic belts, formed during Cenozoic time. Several Mesozoic and Paleozoic IS deposits in the Central Asian Orogenic Belt imply great exploration potential for pre-Cenozoic IS deposits in this area. The presence of Mn-carbonate such as rhodochrosite and manganocalcite (locally Mn-silicate, e.g., rhodonite, helvite) typically in mid to late hydrothermal stages is a common diagnostic feature to discern IS from low-sulfidation (LS) deposits. In addition, the occurrence of intermediate-sulfidation state sulfides such as pyrite, chalcopyrite, sphalerite, galena, and tetrahedrite/tennantite associations are another indicator of the IS type; light-colored (Fe-poor) sphalerite is typical of IS deposits, consistent with relatively oxidized fluids. Elevated fluid salinity is another characteristic, with maximum salinity values of base metal-rich IS veins usually >5 wt% NaCl equiv. The reported IS deposits worldwide show that they develop in compressional volcanic arcs as well as in some extensional settings. In this review, IS deposits are subdivided into " NC (Neutral-Compressional)-type IS " with a low Ag/Au ratio (<60), formed in neutral to compressive stress state volcanic arcs, and " E (Extensional)-type IS ", on the contrary, with a high Ag/Au ratio (>60), formed in extensional settings such as extensional intra-arc, post-collisional orogenic belts, and back-arc settings. Another notable feature of E-type IS deposits is their large Ag endowment compared to NC-type IS. NC-type IS (Au ± Ag) deposits can be associated with porphyry Cu-Au and/or high sulfidation (HS) Au-Cu deposits, and their economic metals are mainly gold and/or silver. By contrast, some E-type IS deposits can occur on the flanks of porphyry molybdenum deposits; E-type IS veins can also occur together with LS precious metal veins in back arcs or extensional continental margins, the most representative examples occurring in Mexico. The occurrence of the two subtypes of IS are largely controlled by the parent magma, with parent magma of NC-type IS primarily derived from depleted mantle or juvenile crust, while parent magma of E-type IS mainly from (ancient?) continental crust. The occurrence of IS deposits is presumably controlled by tectono-magmatic settings and fluid evolution paths. Neutral to compressive stress regime, relatively great depth to an exsolving magma (>4 km) and low exsolution rate of magmatic fluids, plus the presence of syn-ore dikes in conjunction with the development of interconnected fracture networks above the porphyry stock could be conducive for the occurrence of IS (and also HS) Au veins upon porphyry copper deposits (PCDs). Confirmation of sub-types and variations of IS veins can aid in exploration for spatially and genetic-related mineralization types, such as porphyry and HS deposits. [ABSTRACT FROM AUTHOR]

• Multi-cycle W orebodies display similar vertical changes in morphology and mineral assemblage. • Major element contents of minerals from Multi-cycle W orebodies repetitively fluctuate. • A new model is proposed for the formation of the porphyry W Mineralization. The Dongyuan deposit, in the recently identified world-class porphyry–skarn W metallogenic belt, east Jiangnan Orogen, China, is characterized by a set of nearly parallel and horizontal multi-cycle orebodies within cupolas of porphyritic granodiorite. Almost every orebody from the top to the bottom shows similar vertical changes in vein morphology and mineral assemblage from ≤1 cm quartz–feldspar–scheelite–calcite veins to 1–2 cm quartz–feldspar–muscovite–scheelite veins to 2–5 cm quartz–feldspar–muscovite–scheelite veins to ≥5 cm quartz veins. From the bottom to the top of each orebody in every cycle, the mole number of AlIV in K-feldspar decreases, the concentrations of Mn2+ in calcite increases, and the mole number of OH− in muscovite decreases. These changes reflect repetitive fluctuations in the concentrations of major elements that were involved in the precipitation of minerals as well as the physicochemical conditions of fluids during vein formation in the multi-cycle orebodies. The concentrations of Mo are obviously lower in pyrite from the middle orebodies than in the top and bottom orebodies. Our data indicate that the ore-forming fluids were sourced from multi-batch fluids that were exsolved from magma. The ΣLREE/ΣHREE ratios in the scheelite decrease from the upper to lower orebodies. Similar trends are found within a single orebody from the top to the bottom of veins. These trends were due to feldspar fractionation in the magmas and ore-forming fluids, respectively, because the crystallization of feldspar tends to capture LREEs. Therefore, the following model is proposed for the formation of the Dongyuan porphyry W deposit: the magma crystallized first at the roof of the intrusion, causing the underlying magmas to become oversaturated in H 2 O; the exsolved H 2 O then accumulated at the boundary between the crystallized upper part and the underlying magmas; as fluid pressures increased, cracks formed in the overlying crystallized granodiorite, and as a consequence the first cycle of vein networks was formed. This process was repeated as the interface between magma and crystallized rock moved downwards, thus forming the multi-cycle W orebodies that are embedded in the pluton. [ABSTRACT FROM AUTHOR]

• The density of fracture-controlled, magnetite-destructive, alteration veins and halos have a positive correlation with the corresponding outcrops magnetic susceptibility coefficient of variation (CV). • Models of magnetic susceptibility data shows that domains of outcrop with coefficient of variation of >0.3 extend 1–4 km away from the porphyry centers and contrast with lower CV values beyond that distance. • Uncertainty in the mean and coefficient of variation values from 10 susceptibility measurements per ~10 m2 size outcrop is generally < 15% of the values in altered rocks. • Variability in magnetic susceptibility provides a signal that corresponds to vein and alteration intensity that can be used to map ore-forming processes. The Highland Valley Copper porphyry Cu-(Mo) centers compose Canada's largest porphyry Cu mining district, and are hosted in plutonic rocks of the Late Triassic Guichon Creek batholith in the Quesnel terrane, British Columbia. Here we evaluate the relationship between variations in magnetic susceptibility and alteration in order to define a footprint around the porphyry Cu centers using a district-scale dataset of 1610 minimally weathered outcrops and 11,432 magnetic susceptibility measurements. Statistical analysis of the outcrop-based measurements revealed changes in outcrop geometric mean magnetic susceptibility and the coefficient of variation (extent of variability in relation to the mean) are proportional to vein frequency and altered rock volume estimates. At a confidence interval of 95% and 9 degrees of freedom, the average standard error (uncertainty) of the geometric mean and coefficient of variation from 10 magnetic susceptibility outcrop measurements is 7.3% and 13.2%, respectively. Modeling of outcrop magnetic susceptibility data shows that domains of coefficient of variation of >0.3 extend 1–4 km away from the porphyry centers, whereas pronounced susceptibility lows of <10 × 10−3 SI have a smaller footprint centered on the Cu-mineralization. The magnitude of change of magnetic susceptibility coefficient of variation between protolith and altered rocks in the porphyry Cu footprint is greater than the corresponding change in susceptibility geometric means. Thus, with some caveats, variability in magnetic susceptibility provides a good signal that corresponds to vein and alteration intensity, and can potentially be used to map ore-forming processes and to vector to porphyry Cu centers. [ABSTRACT FROM AUTHOR]

• Porphyry-epithermal deposits in Greece were formed from 33 Ma to the Pleistocene. • Several porphyry deposits in Greece share similarities to porphyry gold systems. • HS-IS epithermal deposits and related lithocaps overprint porphyry mineralization. Greece hosts a variety of magmatic-hydrothermal ore deposits/prospects with porphyry- and epithermal styles playing a major role in its total gold endowment. These deposit types are mainly clustered in two areas, the Rhodope- and Attico-Cycladic massifs, and formed from about 33 Ma to the Pleistocene, as a result of back-arc extension in the Aegean Sea, metamorphic core complex formation, and contemporaneous post-subduction and arc magmatism. In the Serbo-Macedonian massif, porphyry Cu-Au deposits include Skouries, Fisoka, Tsikara, Vathi and Gerakario. Causative intrusives are Oligocene to Miocene granodiorites to monzonites. Gold and PGE mineralization is associated with potassic alteration of the intrusives. In the eastern Rhodope massif and the NE Aegean islands, porphyry prospects occur at Pagoni Rachi, Konos Hill, Myli, Melitena (west Thrace), Fakos, Sardes, and Kaspakas (Limnos island) and Stypsi (Lesvos island). Mineralization is associated with Oligocene to Miocene subvolcanics of calc-alkaline to shoshonitic affinity. Feature of these prospects, which they share in common with several porphyry Au-only systems, is their shallow depth of emplacement, the presence of potassic/sodic-calcic and/or phyllic alteration, a strong epithermal overprint, their low Cu content, an extreme Re-enrichment, the multistage introduction of Au, the presence of banded quartz veinlets, and the local presence of tourmaline. New discoveries of porphyry-style mineralization at King Arthur, St. Philippos and Aisymi, increases the gold potential in west Thrace. High-intermediate sulfidation epithermal Au-Ag polymetallic deposits/prospects overprint and/or occur laterally from porphyry-style mineralization, where they are spatially associated with lithocaps of advanced argillic alteration. High-intermediate sulfidation Au-Ag epithermal mineralization at Perama Hill, Mavrokoryfi and Pefka in west Thrace, and at Pterounda, Mesotopos and Megala Therma on Lesvos island is controlled by steeply-dipping extensional faults within volcanic rocks, without any obvious genetic relationship to spatially-related porphyry-style mineralization. Polymetallic epithermal deposits and prospects contain critical and energy critical metals (e.g., Te, Se, Bi, Sb, In, Ge and Ga), which may be considered as by-products. In the Attico-Cycladic area, porphyry Mo-W mineralization occurs as sheeted quartz veins and stockworks cutting a potassic- to sericitic-altered Miocene granodiorite stock in the Lavrion district. Bonanza grade Au- and/or Ag-rich veins with epithermal affinities crosscut metamorphic rocks at Lavrion, and on Syros, Tinos, Antiparos and Anafi islands. Milos island is characterized by shallow submarine volcanic-hosted IS-HS epithermal Au-Ag-Te and base metal deposits. Antimony-As-Ag-Au deposits/prospects on Chios, Samos and Kos islands in the eastern Aegean Sea, indicate the potential for Carlin-style mineralization in Greece. Several factors played a role to the metal endowment of the Aegean porphyry-epithermal systems: magma fertility in the source regions, depth of emplacement of causative intrusives, relative contribution of mantle versus crustal material, redox state of subduction-related magmas, and physico-chemical fluid conditions at the site of ore deposition. [ABSTRACT FROM AUTHOR]