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The Tabei Pb–Zn deposit is located adjacent to the well‐known Axi low‐sulphidation epithermal Au deposit in the Tulasu Basin, Chinese Western Tianshan. The homogenization temperatures and salinities of H2O‐rich biphase inclusions in ore‐stage sphalerite and calcite from Tabei range from 100 to 170°C and 0.4 to 6.2 wt% NaCleq, respectively. The δ13CV‐PDB and δ18OV‐SMOW values of calcite range from 0.9‰ to 1.5‰ and 5.6‰ to 6.7‰, respectively. The δ18OH2O and δDH2O values of hydrothermal fluids vary from −7.0‰ to −5.9‰ and −120.8‰ to −111.1‰, respectively. The in‐situ δ34SV‐CDT values of sulphides range from 7.5‰ to 8.0‰ (average 7.7‰). The in‐situ Pb isotopic compositions of galena and (87Sr/86Sr)0 ratios of sphalerite resemble those of Au‐bearing pyrite and quartz of Axi deposit, respectively, as well as the ore‐hosting volcanic rocks. These isotopic compositions indicate that the ore metals were derived from the ore‐hosting volcanic rocks, with the ore‐forming fluids consisting predominantly of circulating meteoric water. The absence of coexisting two‐phase vapour and liquid fluid inclusions and the presence of abundant banded coarse‐grained quartz crystals with dog tooth and comb textures at Tabei, suggest that the sulphides precipitated slowly due to conductive cooling. The high sulphide abundance, sulphide assemblage (pyrite + Fe‐poor sphalerite + galena + chalcopyrite), ore textures and isotopic compositions suggest that Tabei represents an intermediate‐sulphidation epithermal deposit. The Axi‐Tabei Au–Pb–Zn epithermal system constitutes a hybrid consisting of Au veins at shallow level and Pb–Zn veins at depth, suggesting that the base metals remain highly prospective beneath the identified Au orebodies at Axi. [ABSTRACT FROM AUTHOR]

The Jiamante Au deposit is one of the important deposits in the Axi ore cluster of the Western Tianshan, Xinjiang. The orebodies occurring mainly as quartz‐sulphide veins are hosted in Late Devonian volcanoclastic rocks and granitic porphyries, and structurally controlled by a group of NNW‐ and NNE‐ trending extensional faults and volcanic breccias. Primary metallic minerals are chalcopyrite, galena, pyrite, sphalerite, and native gold, with minor amounts of bismuthinite and bismuth. Nonmetallic minerals are dominated by quartz, sericite, chlorite, and calcite. Medium to low temperature hydrothermal alterations are well developed and characterized by silicification, beresitization, phyllic alteration, and chloritization. Two hydrothermal stages were identified: (a) the main‐ore quartz‐sulphide stage; and (b) the post‐ore quartz‐calcite stage. Microthermometric measurements indicate that the primary biphase liquid‐rich aqueous fluid inclusions within quartz of the main‐ore stage homogenize at temperatures (Th) of 176 to 251°C and have salinities of 2.1 to 7.4 wt% NaCleqv. A lower range of homogenization temperatures (169 to 212°C) and salinities (1.6 to 5.2 wt% NaCleqv) were obtained in calcite of the post‐ore stage. The fluid characteristics of moderate to low temperatures and salinities imply that the ore‐forming process occurred in an epithermal environment. In addition, there is a positive relationship between Th and salinities consistent with the fluid mixing trend. Together with H–O isotopic data (δDH2O = −118 to −97‰ and δ18OH2O = −5.5 to −1.6‰) and fluid characteristics, it is suggested that the ore‐forming fluids were a mixture of magmatic and meteoric waters. The δ13C values for CO2 in the hydrothermal fluids range from −3.2 to −2.7‰, and the sulphides have δ34S values of −5.2 to 2.9‰ with relatively uniform Pb isotopic compositions (206Pb/204Pb = 18.228 to 18.287, 207Pb/204Pb = 15.574 to 15.617, and 208Pb/204Pb = 38.151 to 38.251), indicating that the ore‐forming materials were magmatic sources that were derived directly from magmatic fluids and/or leached from volcanic‐subvolcanic rocks by hydrothermal fluids. Combined with the evidence from the mineralization and alteration, fluid inclusions, and C–H–O–S–Pb isotopes suggest that the Jiamante deposit is an intermediate‐sulphidation epithermal Au deposit. A combination of fluid mixing and fluid–rock interactions is inferred as the important factors causing ore deposition. According to the close spatial and temporal relationship between intermediate‐epithermal deposits and porphyry deposits, it is further suggested that porphyry‐type mineralization should have a good potential at the deep sites of the Jiamante deposit and its vicinity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The initial ore-forming fluids were magmatic water, with input of meteoric water with time. • Fluid phase separation and mixing triggered the Pb-Zn-Ag and Sb precipitation, respectively. • Keyue is the distal Pb-Zn-Sb-Ag mineralization centered on the Cuonadong leucogranites. • Pegmatite-skarn-type W-Sn-Be deposits may occur at deeper sites beneath the Keyue area. The Keyue Pb-Zn-Sb-Ag polymetallic deposit is located within the North Himalayan Metallogenic Belt (NHMB). This study aims to clarify whether the Keyue deposit has close association in time and space with magmatism, and discuss the significance for further exploration. Orebodies are hosted by the Lower Jurassic Ridang Formation black carbonaceous slate and controlled by the NE-trending faults. Keyue is characterized by multiple stages of hydrothermal veins, including Mn-Fe Carbonate-sulfide (I), quartz-sulfide-sulfosalt mineral (II) and quartz-calcite-stibnite veins (III). Hydrothermal minerals contain six types of fluid inclusions, including H 2 O-rich bi-phase aqueous (type I), pure CO 2 (type II), CO 2 -rich H 2 O-CO 2 -NaCl tri-phase (type III), H 2 O-rich H 2 O-CO 2 -NaCl tri-phase (type IV), halite-bearing tri-phase (type V) and halite-bearing H 2 O-CO 2 -NaCl multiphase inclusions (type VI). All six types of inclusions were observed in stage II quartz, whereas only types I and III inclusions in stage I siderite and sphalerite and type I inclusions in stage III quartz and calcite. Type I inclusions in stage I display total homogenization temperatures (T h, total) ranging from 250.1 to 289.3 °C, with salinities of 9.6–16.3 wt% NaCleq. Types I, III, IV and V inclusions in stage II yield T h, total of 175.5–282.7 °C, 188.8–286.3 °C, 214.3–287.5 °C and 198.3–266.0 °C, with corresponding salinities of 4.0–21.5 wt% NaCleq, 0.6–2.9 wt% NaCleq, 0.0–11.0 wt% NaCleq and 30.1–33.2 wt% NaCleq, respectively. Type I inclusions in stage III have T h,total values of 172.3–240.7 °C and salinities of 3.1–12.6 wt% NaCleq. Fluid phase separation occurred in stages I and II, resulting in CO 2 and H 2 S release, pH increase and rapid Pb-Zn-Ag precipitation, whereas mixing of magmatic fluids and meteoric water in stage III caused the cooling, dilution and stibnite precipitation. Fluid inclusion analysis and C-H-O isotopic compositions indicate that the initial hydrothermal fluids were magmatic water, with increasing input of meteoric water with time. The δ34S CDT values of sulfides from three stages are similar and range from 4.8 to 10.3 ‰ (average 7.7 ‰), showing characteristics of mixture of magmatic and sedimentary sulfur. The Pb isotopic compositions of sulfides are closely consistent with those of Cenozoic leucogranite and Precambrian metamorphic crystalline basement in the NHMB, suggesting that the ore-forming metals were sourced from the hidden causative Himalayan leucogranite formed by the decompression melting of metamorphic crystalline domains. Combining evidence from geochronology, fluid inclusions, isotopes suggest that the Keyue Pb-Zn-Sb-Ag and Cuonadong W-Sn-Be mineralization at different locations around the Cuonadong Dome constitute an integrated magmatic-hydrothermal system, with the distal end-member Pb-Zn-Sb-Ag veins centered on the Cuonadong leucogranites-related W-Sn-Be mineralization. Pegmatite-skarn-type W-Sn-Be polymetallic mineralization may occur at deeper sites beneath the Keyue area, and the distal Pb-Zn-Sb-Ag veins controlled by faults within strata also need more attention around these leucogranite domes in the NHMB. [ABSTRACT FROM AUTHOR]

[Display omitted] • The initial ore-forming fluids were magmatic water, mixing with meteoric water. • The metals were derived from the hosing volcanic rocks and hidden causative pluton. • Fluid phase separation caused the formation of liquid bismuth and invisible gold. • The liquid bismuth collector model is responsible for the Au-Bi association. • Kuruer is a subepithermal Cu-Au mineralization related with the hidden porphyries. The Kuruer Cu-Au deposit is located in the Wusun Range of Yili Block, Chinese Western Tianshan, where numerous epithermal Au, skarn Fe-Cu and porphyry Mo-Cu deposits have been recognized. Petrography, fluid inclusions, S-Pb-H-O isotopes, field emission-scanning electron microscopy (FE-SEM) plus energy dispersive spectrometer (EDS) and electron microprobe analysis (EMPA) have been carried out to constrain the genesis of the Kuruer deposit and its implication for further exploration. The minerlization is hosted by volcanic rocks and occur as veins and veinlets structurally controlled by NW-trending faults. Three ore-forming stages were recognized, including quartz-sulfides-bismuth-gold stage (I), quartz-chalcopyrite stage (II) and calcite-chlorite-chalcopyrite stage (III). Six types of fluid inclusions were identified in stage I quartz, including monophase vapor inclusions (type 1), liquid-rich biphase inclusions (type 2), vapor-rich biphase inclusions (type 3), H 2 O-rich CO 2 -H 2 O triphase inclusions (type 4), CO 2 -rich CO 2 -H 2 O triphase inclusions (type 5) and solid halite-bearing triphase inclusions (type 6), whereas only type 2 inclusions were recognized in stage II quartz and stage III calcite. Types 2, 3, 4 and 6 inclusions in stage I have homogenization temperature (T h) ranges of 184–359 °C, 209–252 °C, 250–319 °C and 229–263 °C, with salinity ranges of 4.1–8.5 wt% NaCleq, 5.9–6.9 wt% NaCleq, 1.0–6.0 wt% NaCleq and 32.7–33.9 wt% NaCleq, respectively. Type 2 inclusions in stages II and III have T h varying from 144 to 212 °C and 114 to 163 °C, with salinities of 0.2–6.7 wt% NaCleq and 0.1–3.1 wt% NaCleq, respectively. The in-situ δ34S values of sulfides in stage I range from −4.66 to 0.34‰. The 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of stage I chalcopyrite vary from 18.295 to 18.954, 15.568 to 15.673 and 38.109 to 38.817, respectively, which are consistent with those of Early Carboniferous Dahalajunshan Formation volcanic rocks and granitoids from the Wusun Range. The values of δ18O H2O-VSMOW calculated from δ18O quartz and δD H2O-VSMOW of stage I quartz range from 0.0 to 2.4‰ and −118.6 to −109.3‰, respectively. These isotopic compositions indicate that both metals and sulfur were sourced from the hosting volcanic rocks and hidden causative pluton, while the initial ore-forming fluids were magmatic in origin, with increasing involvement of meteoric water with time. Evidence from mineralogy, mineral geochemistry and fluid inclusions indicates that the initial fluid phase separation triggered the precipitation of "invisible" gold within pyrite and chalcopyrite during stage I. Subsequently, the decrease of f S2 due to the escape of H 2 S (g) and sulfide precipitation and cooling caused the formation of liquid bismuth from solutions. The bismuth melts have scavenged Au in situ from the residual solutions, resulting in the formation of Bi-Au inclusions within the fractures and intergranular spaces of earlier pyrite. For stages II and III, dilution and cooling due to input of meteoric water facilitated the chalcopyrite precipitation. The Kuruer Cu-Au deposit is classified as a subepithermal mineralization associated with porphyries. Porphyry Cu-Au mineralization could have developed beneath the Kuruer and its vicinity. [ABSTRACT FROM AUTHOR]

• The Lailisigao'er and Qixing deposits are coeval and both related to the granodiorite porphyries. • Fluid immiscibility and mixing were the precipitation mechanism for Mo and Pb-Zn, respectively. • The Qixing Pb-Zn deposit represents a distal end-member centered on Mo-mineralized porphyries. • Concealed porphyry Cu-Mo mineralization may be developed underneath No. 3571 and Qixing areas. The Nailenggele orefield, located in the northwestern Chinese Tianshan Orogenic Belt, is composed of the Lailisigao'er Mo deposit, No. 3571 Cu prospect and Qixing Pb-Zn deposit. Lailisigao'er is a typical porphyry deposit with characteristic veinlet-disseminated ores and potassic, phyllic and propylitic alterations. No. 3571, situated in the peripheral of Lailisigao'er, is characterized by large amounts of oxidized ores at surface with limited intrusions outcropped. Qixing, about 3 km from Lailisigao'er, is characterized by quartz-sulfide veins controlled by fractures. This study aims to examine the genetic relationships between these deposits and/or occurrences, and discuss the significance for further exploration in the orefield and elsewhere in the region. LA-ICP-MS U-Pb dating on zircons from the ore-bearing porphyry in the Lailisigao'er deposit yielded an age of 367.5 ± 4.8 Ma. The molybdenite Re-Os and sphalerite Rb-Sr isochron ages recalculated from previously published data are 365.9 ± 2.1 Ma for Lailisigao'er and 362.0 ± 5.7 Ma for Qixing, respectively, suggesting that they are coeval and both related to the granodiorite porphyries. Three types of fluid inclusions occur in the Mo-bearing quartz from Lailisigao'er, including two-phase aqueous inclusions (Type I), solid mineral-bearing aqueous inclusions (Type II) and CO 2 -H 2 O inclusions (Type III). The total homogenization (T h) temperatures cluster from 260 to 320 °C (to liquid) for type I inclusions, 310 to 332 °C (to liquid) for type II inclusions, and 268 to 324 °C (to CO 2 phase) for type III inclusions. The salinities are mainly in the ranges of 2.0–8.0, 32.9–42.0, and 1.4–5.5 wt% NaCleq for types I, II and III inclusions, respectively. By contrast, only type I inclusions were identified in the Pb-Zn-bearing quartz from Qixing, with T h values of 149–261 °C and salinities of 1.7–5.3 wt% NaCleq. The δ34S CDT values of hydrothermal sulfides from Lailisigao'er, No. 3571 and Qixing range from 2.8‰ to 4.0‰, 4.0‰ to 4.6‰ and 0.7‰ to 4.9‰, respectively. Sulfides from these three locations have uniform Pb isotopic compositions. The (87Sr/86Sr) 0 ratios of fluid inclusions (average 0.70971) in Mo-bearing quartz at Lailisigao'er and sphalerite (average 0.71020) at Qixing are similar to those of Mo-mineralized porphyries (average of 0.70886) from Lailisigao'er. The δ18O H2O and δD H2O values of Pb-Zn-bearing quartz from Qixing are similar to those of Mo-bearing quartz from Lailisigao'er, both plotting close to the field of magmatic water but shifted toward the meteoric line. These geochronological, fluid inclusions and isotopic data suggest that the mineralization at different localities in the Nailenggele orefield constitutes part of an integrated magmatic-hydrothermal system centered on the Lailisigao'er porphyry Mo deposit, with the Qixing Pb-Zn polymetallic deposit representing a distal end-member. Both metals and sulfur were dominantly derived from porphyritic intrusions, whereas the ore-forming fluids were initially derived from the magmatic intrusions, with increasing involvement of meteoric water in time and distance from magmatic-hydrothermal center. Fluid immiscibility in the early stage and fluid mixing in the later stage, together with cooling, were responsible for ore precipitation. Based on this mineralization model, it is inferred that concealed porphyry Cu-Mo mineralization may be developed underneath the No. 3571 and Qixing. [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]

Graphical abstract Kendenggao’er deposit, the only Late Carboniferous deposit in Boluokenu metallogenic belt, is a typical skarn Cu-Mo deposit. The hydrothermal system of Kendenggao’er deposit is complicated, and various types of fluid inclusions and several fluid evolution episodes have been inferred in our study. These give a clear constraint for the origin and evolution of Kendenggao’er skarn deposit, furthermore, will provide a better insight into understanding the ore-forming mechanisms for other skarn type in the Boluokenu. Highlights • Kendenggao’er deposit is a typical skarn Cu-Mo deposit. • The ore-forming fluids of pre-ore and main-ore stages are of magmatic origin. • The ore-forming materials were derived from the host magmatic rocks. • Two types of immiscibility occurred in the skarn and hydrothermal system. Abstract The Boluokenu Range is one of the most important metallogenic belts in northwest China, and it contains numerous Fe, Cu, Mo, Au etc deposits. The Kendenggao’er Cu-Mo deposit is located in the eastern segment of the Boluokenu metallogenic belt within the Western Tianshan orogeny. Skarn and Cu-Mo orebodies occur as lamellae or lenses along the contacts between different units of the Upper Carboniferous Dongtujinhe Formation and the Aimujin granitic intrusions. Based on field investigations and petrographic observations, three main metallogenic stages of skarn formation and ore deposition have been distinguished: (1) The pre-ore stage is characterized by the formation of garnet, wollastonite and diopside and high-temperature, hypersaline hydrothermal fluids with oxygen isotopic compositions that are similar to those of magmatic fluids. These fluids were most likely generated by the separation of brine from the silicate melt due to the immiscibility of primary magmatic fluids that occurred at a depth of approximately 1 km with inferred lithostatic pressure conditions of 300 bars. (2) The main-ore stage coincides with the replacement of garnet and diopside by vesuvianite, epidote, sulfides and quartz. The hydrothermal fluids of this stage are represented by V-type (vapor-rich) fluid inclusions that coexist with L-type (liquid-rich) inclusions. The oxygen isotope (δ18O H2O) values of the main-ore stages are in a narrow range of 7.5–9.9‰, which indicates that the mineralization-related fluid is also of magmatic origin. Based on the fluid inclusion and stable isotopic data, it can be concluded that the ore-forming fluid evolved by the boiling of the magmatic fluids that likely occurred at a depth of ∼1 km and hydrostatic pressure of ∼100 bars, and that this was the predominant mechanism for the large-scale precipitation in the Kendenggao’er Cu-Mo deposit. (3) The post-ore stage is characterized by the development of calcite, quartz and chlorite. The fluids during this stage are represented by the L-type inclusions, which mainly show low-salinity and low-homogenization temperatures. These fluids yield the lowest δ18O H2O values (−2.8 to 3.7‰). The above data indicate that the post-ore stage fluids originated from the mixing of residual main-ore stage fluids with various proportions of external water (low salinity, low temperature). No boiling occurred at this stage at the low temperatures. The δ34S values of the sulfides range from −4.3 to 1.9‰, and the 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values of the sulfides range from 18.220 to 18.554, 15.608 to 15.812 and 38.080 to 39.055, respectively. The S and Pb isotopic compositions indicate that the ore materials were mainly derived from magmas. Taken together, these geologic, geochemical, and isotopic data confirm that Kendenggao’er is a typical skarn deposit. [ABSTRACT FROM AUTHOR]

The hydrothermal fluids responsible for the Mo mineralization stage were mainly derived from magmatic fluids that were characterized by high salinity and contained more Mo content. The Cu ore-forming fluids were enriched in Cu, As, and volatiles (e.g., CO 2 , HF), and originated from the mixing of magmatic fluids (generated by condensation of the low-salinity vapor after fluid boiling) and meteoric water. [Display omitted] • The Dabate porphyry Cu-Mo deposit is characterized by "early Cu and late Mo, external Cu and internal Mo". • The Cu mineralization fluids were produced by condensation of the vapor phase generated by fluid boiling. • The subtle changes influid feature resulted in the temporal separation of the Cu and Mo mineralization. • The spatial separation of the Cu and Mo mineralization could be attributed to different partitioning behaviors of Cu and Mo during the phase separation. Dabate deposit is a typical porphyry Cu-Mo deposit in the Western Tianshan, Xinjiang, China. Both the Cu and Mo mineralization are mainly associated with intrusion of rhyolite porphyry. Distinguishing from typical porphyry deposits, the Cu mineralization and Mo mineralization are separated from each other on both the temporal and spatial scales. The Cu orebodies are mainly hosted in the contact zone between the rhyolite porphyry and Tuosiku'ertawu Formation and predominantly occur as fluorite-arsenopyrite-Cu-sulfides ± K-feldspar ± quartz veins (Cu-1 stage), whereas the Mo orebodies are mostly hosted in the inner part of the rhyolite porphyry and are typically presented as Mo-2 stage quartz-molybdenite veins (external Cu and internal Mo). Total homogenization temperatures (T h, L-V) for boiling fluid inclusion assemblage of the Mo-2 stage occurred at 302 to 358 °C, with corresponding salinities of 1.4 to 38.1 wt% NaCl eqv. H-O isotope data indicate that the Mo mineralization fluids were mainly derived from magmatic water. The non-boiling fluids of the Cu-1 stage originated from magmatic fluids and meteoric water, which were characterized by high temperature (323 to 379 °C) and low salinity (2.6 to 5.9 wt% NaCl eqv) as well as Cu, As, and volatile enrichment. These features are different from the initial magmatic fluids of this deposit, indicating that the Cu mineralization may occur before the Mo mineralization (early Cu and late Mo) and the magmatic fluid components of the Cu-1 stage should be derived from the condensation of the low-salinity vapor generated by boiling of the hydrothermal fluids (351 to 405 °C; 1.8 to 40.1 wt% NaCl eqv) for the earliest Mo-1 stage barren quartz veins. The positive δ 34S values (5.5 to 9.8‰) of sulfides indicate that the sulfur in the ore-forming fluids was derived from magma and country rocks. The subtle change in fluid conditions from the high temperature (peak range 340 to 360 °C), alkaline, and slightly more oxidized of the Cu-1 stage to high temperature (peak range = 320 to 340 °C), more reduced, and acidic of the Mo-2 stage gave rise to the temporal separation of Cu and Mo mineralization. The Cu, As, and volatiles (e.g., CO 2 , HF), preferentially partitioned into the vapor phase, were highly enriched in Cu ore-forming fluids, whereas Mo mineralization fluids contained the majority of Mo with strong preference for the brine phase. Therefore, the spatial separation of the Cu and Mo mineralization could be attributed to selectively fractionating between the vapor phase and hypersaline liquid of the Cu and Mo metals during the process of fluid boiling. [ABSTRACT FROM AUTHOR]