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1.
A large number of Paleoproterozoic borate deposits are hosted by the lower units of a volcanic-sedimentary sequence in Liaoning Province, northeastern China, and are a major source of boron in China. The ore-bearing wall rocks in the deposits are serpentinized ultrabasic rocks and carbonates, with layered leptynites, leptites, amphibolites, and migmatites adjacent to the ore. Both the borate ores and country rocks contain tourmaline, although the country rocks have much lower abundances of the mineral. Based on in situ boron isotope measurements using laser ablation–multi-collector–inductively coupled plasma–mass spectrometry (LA–MC–ICP–MS), boron isotope data show that: (1) δ11B values of borate ores range from + 6.8‰ to + 13.9‰ (mean + 10.8‰); (2) tourmalines from the borate ores have δ11B values from + 9.5‰ to + 12.7‰; and (3) the wall rocks within the borate ores yield slightly lower δ11B values ranging from + 5.7‰ to + 7.6‰, and those outside the deposits from − 9.9‰ to − 5.9‰. Positive δ11B values in borates as well as in tourmalines inside the mining area indicate that boron in these Paleoproterozoic borate deposits was derived from marine evaporites. δ34SV-CDT (where V-CDT is Vienna Canyon Diablo Troilite) values of borate ores, serpentinized marbles, and anhydrites range from + 16.1‰ to + 24.7‰, whereas δ13CV-PDB (where V-PDB is Vienna Pee Dee Belemnite) values of marbles range from + 3.2‰ to + 5.9‰. These isotopic characteristics are interpreted to reflect formation in a marine evaporative environment. LA–MC–ICP–MS zircon weighted207Pb/206Pb ages of leptite and serpentinized olivine basalt from the hanging wall of the borate deposits are 2139 ± 13 Ma and 2130 ± 19 Ma, respectively. Therefore, the (~ 2.2 Ga) borate deposits may have originated from marine evaporative boron-bearing sediments, which were interbedded within bimodal volcanic rocks during the early stages of development of the Liaoji rift. 相似文献
2.
The several-hundred-m-thick Miocene Upper Red Formation in northwestern Iran hosts stratiform and fault-controlled copper mineralization. Copper enrichment in the percent range occurs in dm-thick carbonaceous sandstone and shale units within the clastic redbed sequence and consists of fine-grained disseminated copper sulfides (chalcopyrite, bornite, chalcocite) and supergene alteration minerals (covellite, malachite and azurite). The copper mineralization formed after calcite cementation of the primary rock permeability. Copper sulfides occur mainly as replacement of diagenetic pyrite, which, in turn, replaced organic matter. Electron microprobe analysis on bornite, chalcocite and covellite identifies elevated silver contents in these minerals (up to 0.12, 0.72 and 1.21 wt%, respectively), whereas chalcopyrite and pyrite have only trace amounts of silver (<0.26 and 0.06 wt%, respectively). Microthermometric data on fluid inclusions in authigenic quartz and calcite indicate that the Cu mineralization is related to a diagenetic fluid of moderate-to low temperature (Th = 96–160 °C) but high salinity (25–38 wt% CaCl2 equiv.). The range of δ34S in pyrite is −41.9 to −16.4‰ (average −31.4‰), where framboidal pyrite shows the most negative values between −41.9 and −31.8‰, and fine-grained pyrite has relatively heavier δ34S values (−29.2 to −16.4‰), consistent with a bacteriogenic derivation of the sulfur. The Cu-sulfides (chalcopyrite, bornite and chalcocite) show slightly heavier values from −14.6 to −9.0‰, and their sulfur sources may be both the precursor pyrite-S and the bacterial reduction of sulfate-bearing basinal brines. Carbonates related to the ore stage show isotopically light values of δ13CV-PDB from −8.2 to −5.1‰ and δ18OV-PDB from −10.3 to −7.2‰, indicating a mixed source of oxidation of organic carbon (ca. −20‰) and HCO3− from seawater/porewater (ca. 0‰). The copper mineralization is mainly controlled by organic matter content and paleopermeability (intragranular space to large fracture patterns), enhanced by feldspar and calcite dissolution. The Cheshmeh-Konan deposit can be classified as a redbed-type sediment-hosted stratiform copper (SSC) deposit. 相似文献
3.
The Qianfanling Mo deposit, located in Songxian County, western Henan province, China, is one of the newly discovered quartz-vein type Mo deposits in the East Qinling–Dabie orogenic belt. The deposit consists of molybdenite in quartz veins and disseminated molybdenite in the wall rocks. The alteration types of the wall rocks include silicification, K-feldspar alteration, pyritization, carbonatization, sericitization, epidotization and chloritization. On the basis of field evidence and petrographic analysis, three stages of hydrothermal mineralization could be distinguished: (1) pyrite–barite–quartz stage; (2) molybdenite–quartz stage; (3) quartz–calcite stage.Two types of fluid inclusions, including CO2-bearing fluid inclusions and water-rich fluid inclusions, have been recognized in quartz. Homogenization temperatures of fluid inclusions vary from 133 °C to 397 °C. Salinity ranges from 1.57 to 31.61 wt.% NaCl eq. There are a large number of daughter mineral-CO2-bearing inclusions, which is the result of fluid immiscibility. The ore-forming fluids are medium–high temperature, low to moderate salinity H2O–NaCl–CO2 system. The δ34S values of pyrite, molybdenite, and barite range from − 9.3‰ to − 7.3‰, − 9.7‰ to − 7.3‰ and 5.9‰ to 6.8‰, respectively. The δ18O values of quartz range from 9.8‰ to 11.1‰, with corresponding δ18Ofluid values of 1.3‰ to 4.3‰, and δ18D values of fluid inclusions of between − 81‰ and − 64‰. The δ13CV-PDB values of fluid inclusions in quartz and calcite have ranges of − 6.7‰ to − 2.9‰ and − 5.7‰ to − 1.8‰, respectively. Sulfur, hydrogen, oxygen and carbon isotope compositions show that the sulfur and ore-forming fluids derived from a deep-seated igneous source. During the peak collisional period between the North China Craton and the Yangtze Craton, the ore-forming fluids that derived from a deep igneous source extracted base and precious metals and flowed upwards through the channels that formed during tectonism. Fluid immiscibility and volatile exsolution led to the crystallization of molybdenite and other minerals, and the formation of economic orebodies in the Qianfanling Mo deposit. 相似文献
4.
Kafang is one of the main ore deposits in the world-class Gejiu polymetallic tin district, SW China. There are three main mineralization types in the Kafang deposit, i.e., skarn Cu–Sn ores, stratiform Cu ores hosted by basalt and stratiform Cu–Sn ores hosted by carbonate. The skarn mainly consists of garnet and pyroxene, and retrograde altered rocks. These retrograde altered rocks are superimposed on the skarn and are composed of actinolite, chlorite, epidote and phlogopite. Major ore minerals are chalcopyrite, pyrrhotite, cassiterite, pyrite and scheelite. Sulfur and Pb isotopic components hint that the sources of different types of mineralization are distinctive, and indicate that the skarn ore mainly originated from granitic magma, whereas the basalt-hosted Cu ores mainly derived from basalt. Microthermometry results of fluid inclusions display a gradual change during the ore-forming process. The homogenization temperature of different types of inclusions continuously decreases from early to late mineralization stages. The salinities and freezing temperatures exhibit similar evolutionary tendencies with the T homogenization, while the densities of the different types keep constant, the majority being less than 1. Oxygen and hydrogen isotopic values (δ18O and δD) of the hydrothermal fluids fall within ranges of 3.1 to 7.7‰ with an average of 6.15‰, calculated at the corresponding homogenization temperature, and − 73 and − 98‰ with an average of − 86.5‰, respectively. Microthermometry data and H–O isotopes indicate that the ore-forming fluid of the Kafang deposit is mainly derived from magma in the early stage and a mixture of meteoric and magmatic water in late stage. Molybdenite Re–Os age of the skarn type mineralization is 83.4 ± 2.1 Ma, and the stratiform ores hosted by basalt is 84.2 ± 7.3 Ma, which are consistent with the LA-ICP-MS zircon age of the Xinshan granite intrusion (83.1 ± 0.4 Ma). The evidence listed above reflects the fact that different ore styles in the Kafang deposit belong to the same mineralization system. 相似文献
5.
Polymetallic vein-type Zn-Pb deposits are located in the Xiangxi–Qiandong zinc-lead metallogenic belt (XQMB) of the northwestern margin of the Jiangnan Orogen, South China. Ores are mainly found in fault-bounded quartz veins hosted in the upper part of the Banxi Group that consists of low-grade metamorphic sandstone, siltstone with minor tuff interbeds. The Zn-Pb deposits primarily contain sphalerite, galena, chalcopyrite and pyrite, accompanied by quartz and minor calcite. Zinc, lead, copper, indium and gallium are enriched in these ores. Investigation of the ore fluid reveals low temperature (87–262 °C) with scattered salinity (range from 2.73 to 26.64 wt% NaCleqv.). Hydrogen and oxygen isotopic compositions of fluid inclusions in quartz indicate mixing of magmatic hydrothermal fluid and meteoric water (δ18OH2O SMOW = 0.2‰ to 4.2‰; δDH2O SMOW = −126‰ to −80‰). Carbon and oxygen isotopic composition of carbonate samples indicate the magmatic hydrothermal origin of CO32− or CO2 in ore-forming fluid (δ13CPDB = −6.9‰ to −5.7‰, δ18OSMOW = 11.3‰ to 12.7‰). Sulfur and lead isotopic compositions (δ34SVCDT = 8.8–14.2‰ and 206Pb/204Pb = 17.156–17.209, 207Pb/204Pb = 15.532–15.508, 208Pb/204Pb = 37.282–37.546) demonstrate that sulfur sources were relatively uniform, and low radiogenic lead isotopic compositions indicate that ore metals were derived from a relatively unradiogenic source, probably by mixing of mantle with crust. Therefore, polymetallic vein-type Zn-Pb mineralization in this area probably arose from a magmatic-related hydrothermal system, and the deposition of sulfides occurred in response to cooling and boiling of magmatic hydrothermal fluids (high salinity, high δ18OH2O and δDH2O and metal-bearing), and is mainly the result of emplacement into open space and mixing with meteoric water (low salinity, low δ18OH2O and δDH2O). This study provides direct evidence that magmatism was involved in the ore-forming processes of the low temperature metallogenic district, South China, and it raises awareness about the presence of polymetallic vein-type Zn-Pb deposits in the northwest margin of Jiangnan Orogen and their potential as a source of zinc, copper, indium and gallium. 相似文献
6.
Carbon (δ13CPDB) and oxygen (δ18OSMOW) isotopic compositions of auriferous quartz-carbonate veins (QCVs) of gold deposits from Sangli, Kabuliyatkatti, Nagavi, Nabapur and Mysore mining areas developed on the Central Lode system of the Gadag Gold Field (GGF) in the Neoarchaean Gadag schist belt of the Dharwar Craton, southern India have been examined for the first time to understand the origin of the mineralising fluids. In majority of the samples (46 out of 49), δ13Cpdb of carbonates of the QCVs fall in the range from − 2.2‰ to − 9.7‰ and the δ18O values range from 12.0‰ to 30.5‰ SMOW. The calculated fluid δ13C∑ C compositions for these deposits range from − 2.1‰ to − 9.6‰ and δ18OH2O from 6.8‰ to 25.9‰, respectively. Carbonate δ13C and fluid δ13C∑ C compositions of the carbonates of the QCVs of the GGF are not only distinct from the carbon isotope range of marine carbonates or meta-sedimentary carbonates of the Chitradurga schist belt, but are consistent with C-isotope values of magmatic (− 5 ± 3‰, Burrows et al., 1986) and/or mantle (− 6 ± 2‰, Ohmoto, 1986) carbonates. As dissolution/decarbonation reactions during metamorphism of pre-existing carbonate/carbonated rocks produce CO2 with δ13C values similar to or more enriched than parent rock, the carbonate or fluid δ13C ratios of the QCVs (which fall in the compositional range of mantle/magmatic derived CO2 or carbonates) obtained in this work cannot be the result of metamorphism. The present study corroborates our previous reports from Ajjanahalli and G.R. Halli gold deposits (Sarangi et al., 2012) occurring in the vicinity of the southern extension of the same crustal scale shear zone on which all the GGF deposits are located.The age of gold mineralisation in this area has been reported to be 2522 ± 6 Ma by Sarma et al., 2011. Chardon et al. (2011) have proposed large-scale remobilization of the older gneissic basement, as well as, emplacement of juvenile granites between 2559 Ma and 2507 Ma, close to the crustal scale shear zone along the eastern margin of the Chitradurga schist belt. Based on these observations and our isotope studies, it is proposed that gold mineralising fluids were derived from mantle/juvenile magmatic melts and were channelled through crustal scale shear zones to give rise to the gold deposits in the GGF. 相似文献
7.
Determining Ge isotopic compositions of sulfides is important to understand the ore-forming processes. Single step anion-exchange chromatography was previously used to recover Ge from silicates and lignites. We apply this procedure to recover Ge from sulfides before determining Ge isotopic compositions by hydride generation (HG)-MC-ICP-MS. Germanium is quantitatively recovered by the proposed sample preparation method. There are no obvious isotope biases for Ge-bearing solutions containing significant amounts of Cu, Sn, and W. However, δ74Ge values show obvious shifts if the solutions contain high Zn, Pb, and Sb, which is possibly attributed to suppression of germane formation that fractionates Ge isotopes. The long-term reproducibility for Ge standard solution is about ± 0.18‰ for δ74Ge. Spex and Merck standard solutions yield mean δ74Ge values of − 0.70 ± 0.19‰ and − 0.36 ± 0.08‰, respectively. The calculated δ74Ge value (− 5.13‰) of sphalerite standard based on doping experiments is indistinguishable from those of sphalerite without doping (− 5.05‰ and − 5.01‰). Sulfides from the Jinding, Shanshulin, and Tianqiao Pb–Zn deposits in SW China have δ74Ge values of − 4.94‰ to + 2.07‰. The paragenetic sequence of sulfides from the Shanshulin and Tianqiao Pb–Zn deposits is pyrite, sphalerite and galena from early to late. Sulfides from the same ore show a trend of δ74Gepyrite < δ74Gesphalerite < δ74Gegalena, which may be controlled by the kinetic or Rayleigh fractionation. 相似文献
8.
The large (>180 Kt WO3 and at least 10–15 t Au) Vostok-2 deposit is situated in a metallogenic belt of W, Sn-W, Au, and Au-W deposits formed in late to post-collisional tectonic environment after cessation of active subduction. The deposit is related to an ilmenite-series high-K calc-alkaline plutonic suite that, by its petrologic signatures, is transitional between those at W-dominant and Au-dominant reduced intrusion-related deposits. Consistently, besides large W-Cu skarns of the reduced type, the deposit incorporates quartz stockworks with significant Au-W-Bi mineralization also formed in a reduced environment. The hydrothermal stages include prograde and retrograde, essentially pyroxene skarns, hydrosilicate (amphibole, chlorite, quartz) alteration, and phyllic (quartz, sericite, albite, apatite, and carbonate) alteration assemblages. These assemblages contain abundant scheelite associated with pyrrhotite, chalcopyrite and, at the phyllic stage, also with Bi minerals, As-Bi-Sb-Te-Pb-Zn sulfides and sulfosalts, as well as Au mineralization. The fluid evolution included hot, high-pressure (420–460 °C, 1.1–1.2 kbar), low-salinity (5.4–6.0 wt% NaCl-equiv.) aqueous fluids at the retrograde skarn stage, followed by lower temperature cyclic releases of high-carbonic, low salinity to non-carbonic moderate-salinity aqueous fluids. At the hydrosilicate stage, a high-carbonic, CH4-dominated, hot (350–380 °C) low salinity fluid was followed by cooler (300–350 °C) non-carbonic moderate-salinity (5.7–14.9 wt% NaCl-equiv.) fluid. At the phyllic stage, a high-carbonic, CO2-dominated, moderately-hot (330–355 °C, 0.9 kbar) low salinity fluid was followed by cooler (230–265 °C) non-carbonic moderate-salinity (6.6–12.0 wt% NaCl-equiv.) fluid. A homogenized magmatic source of water (δ18OH2O = +8.3 to +8.7‰), and a sedimentary source of sulfur (δ34S = −6.9 to −6.2‰) and carbon (δ13Cfluid = −20.1 to −14.9‰) at the hydrosilicate stage are suggested. A magmatic source of water (δ18O = +8.6 to +9.2‰) and a sedimentary source of sulfur (δ34S = −9.3 to −4.1‰) but a magmatic (mantle- to crustal-derived) source of carbon (δ13Cfluid = −6.9 to −5.2‰) are envisaged for fluids that formed the early mineral assemblage of the phyllic stage. Then, the role of sedimentary carbon again increased toward the intermediate (δ13Cfluid = −16.4 to −14.5‰) and late (δ13Cfluid = −16.3 to −14.7‰) phyllic mineral assemblages. The magmatic differentiation was responsible for the fluid enrichment in W, whereas Au and Bi could also have been sourced from mafic magma. The decreasing temperatures, together with elevated Ca content in non-boiling fluids, promoted scheelite deposition at the early hydrothermal stages. The most intense scheelite deposition at the phyllic stage was caused by CO2 removal due to boiling of CO2-rich fluids; further cooling of non-boiling fluids favoured joint deposition of scheelite, Bi and Au. 相似文献
9.
The Neoproterozoic (593–532 Ma) Dahongliutan banded iron formation (BIF), located in the Tianshuihai terrane (Western Kunlun orogenic belt), is hosted in the Tianshuihai Group, a dominantly submarine siliciclastic and carbonate sedimentary succession that generally has been metamorphosed to greenschist facies. Iron oxide (hematite), carbonate (siderite, ankerite, dolomite and calcite) and silicate (muscovite) facies are all present within the iron-rich layers. There are three distinctive sedimentary facies BIFs, the oxide, silicate–carbonate–oxide and carbonate (being subdivided into ankerite and siderite facies BIFs) in the Dahongliutan BIF. They demonstrate lateral and vertical zonation from south to north and from bottom to top: the carbonate facies BIF through a majority of the oxide facies BIF into the silicate–carbonate–oxide facies BIF and a small proportion of the oxide facies BIF.The positive correlations between Al2O3 and TiO2, Sc, V, Cr, Rb, Cs, Th and ∑REE (total rare earth element) for various facies of BIFs indicate these chemical sediments incorporate terrigenous detrital components. Low contents of Al2O3 (<3 wt%), TiO2 (<0.15 wt%), ∑REE (5.06–39.6 ppm) and incompatible HFSEs (high field strength elements, e.g., Zr, Hf, Th and Sc) (<10 ppm), and high Fe/Ti ratios (254–4115) for a majority of the oxide and carbonate facies BIFs suggest a small clastic input (<20% clastic materials) admixtured with their original chemical precipitates. The higher abundances of Al2O3 (>3 wt%), TiO2, Zr, Th, Cs, Sc, Cr and ∑REE (31.2–62.9 ppm), and low Fe/Ti ratios (95.2–236) of the silicate–carbonate–oxide facies BIF are consistent with incorporation of higher amounts of clastic components (20%–40% clastic materials). The HREE (heavy rare earth element) enrichment pattern in PAAS-normalized REE diagrams exhibited by a majority of the oxide and carbonate facies BIFs shows a modern seawater REE signature overprinted by high-T (temperature) hydrothermal fluids marked by strong positive Eu anomalies (Eu/Eu1PAAS = 2.37–5.23). The low Eu/Sm ratios, small positive Eu anomaly (Eu/Eu1PAAS = 1.10–1.58) and slightly MREE (middle rare earth element) enrichment relative to HREE in the silicate–carbonate–oxide facies BIF and some oxide and carbonate facies BIFs indicate higher contributions from low-T hydrothermal sources. The absence of negative Ce anomalies and the high Fe3+/(Fe3+/Fe2+) ratios (0.98–1.00) for the oxide and silicate–carbonate–oxide BIFs do not support ocean anoxia. The δ13CV-PDB (−4.0‰ to −6.6‰) and δ18OV-PDB (−14.0‰ to −11.5‰) values for siderite and ankerite in the carbonate facies BIF are, on average, ∼6‰ and ∼5‰ lower than those (δ13CV-PDB = −0.8‰ to + 3.1‰ and δ18OV-PDB = −8.2‰ to −6.3‰) of Ca–Mg carbonates from the silicate–carbonate–oxide facies BIF. This feature, coupled with the negative correlations between FeO, Eu/Eu1PAAS and δ13CV-PDB, imply that a water column stratified with regard to the isotopic omposition of total dissolved CO2, with the deeper water, from which the carbonate facies BIF formed, depleted in δ13C that may have been derive from hydrothermal activity.Integration of petrographic, geochemical, and isotopic data indicates that the silicate–carbonate–oxide facies BIF and part of the oxide facies BIF precipitated in a near-shore, oxic and shallow water environment, whereas a majority of the oxide and carbonate facies BIFs deposited in anoxic but Fe2+-rich deeper waters, closer to submarine hydrothermal vents. High-T hydrothermal solutions, with infusions of some low-T hydrothermal fluids, brought Fe and Si onto a shallow marine, variably mixed with detrital components from seawaters and fresh waters carrying continental landmass and finally led to the alternating deposition of the Dahongliutan BIF during regression–transgression cycles.The Dahongliutan BIF is more akin to Superior-type rather than Algoma-type and Rapitan-type BIF, and constitutes an additional line of evidence for the widespread return of BIFs in the Cryogenian and Ediacaran reflecting the recurrence of anoxic ferruginous deep sea and anoxia/reoxygenation cycles in the Neoproterozoic. In combination with previous studies on other Fe deposits in the Tianshuihai terrane, we propose that a Fe2+-rich anoxic basin or deep sea probably existed from the Neoproterozoic to the Early Cambrian in this area. 相似文献
10.
The Cipoeiro gold deposit,Gurupi Belt,Brazil: Geology,chlorite geochemistry,and stable isotope study
《Journal of South American Earth Sciences》2007,23(2-3):242-255
The Cipoeiro gold deposit, located in the Gurupi Belt, northern Brazil, is hosted by tonalites of 2148 Ma. The deposit is controlled by splays related to the major strike-slip Tentugal shear zone, and at the deposit scale, the mineralization is confined to ductile–brittle shear zones. Mineralization style comprises thick quartz veins and narrow and discontinuous quartz-carbonate veinlets associated with disseminations in altered host rocks. The postmetamorphic hydrothermal paragenesis is composed of quartz, calcite, chlorite, white mica (phengite), pyrite, and minor albite. Electron microprobe analysis of chlorites reveals a relatively uniform chemical composition at depths of more than 100 m. The chlorites are characterized by (Fe + Mg) ratios between 0.37 and 0.47 and AlIV ranging between 2.22 and 2.59 a.p.f.u. and are classified as Fe-chlinochlore. Temperatures calculated by applying the AlIV contents of chlorites yield a relatively narrow interval of 305 ± 15°C. Stable isotope (O, H, C, S) compositions have been determined in silicate, carbonate, and sulfide minerals. The δ18O and δD values of the mineralizing fluid range from +2.4 to +5.7 and from −43‰ to −20‰, respectively, and are interpreted as having a metamorphic origin. The δ13C values of fluid CO2 are in the range −10.7‰ to −3.9‰, whereas the fluid δ34S is around 0‰. Carbon and sulfur compositions are not diagnostic of their sources, compatible as they are with mantle, magmatic, or average crustal reservoirs. The hydrothermal paragenesis, chlorite–pyrite coexistence, temperature of ore formation, and sulfur isotope evidence indicate relatively reduced fO2 conditions for the mineralizing fluid. Geologic, chemical, and isotopic characteristics of the Cipoeiro deposit are compatible with the class of orogenic gold deposits. 相似文献
11.
The Hattu schist belt is located in the western part of the Archaean Karelian domain of the Fennoscandian Shield. The orogenic gold deposits with Au–Bi–Te geochemical signatures are hosted by NE–SW, N–S and NW–SE oriented shear zones that deform 2.76–2.73 Ga volcanic and sedimentary sequences, as well as 2.75–2.72 Ga tonalite–granodiorite intrusions and diverse felsic porphyry dykes. Mo–W mineralization is also present in some tonalite intrusions, both separate from, and associated with Au mineralization. Somewhat younger, unmineralized leucogranite intrusions (2.70 Ga) also intrude the belt. Lower amphibolite facies peak metamorphism at 3–5 kbar pressures and at 500–600 °C temperatures affected the belt at around 2.70 Ga and post-date hydrothermal alteration and ore formation. In this study, we investigated the potential influence of magmatic-hydrothermal processes on the formation of orogenic gold deposits on the basis of multiple stable isotope (B, S, Cu) studies of tourmaline and sulphide minerals by application of in situ SIMS and LA ICP MS analytical techniques.Crystal chemistry of tourmaline from a Mo–W mineralization hosted by a tonalite intrusion in the Hattu schist belt is characterized by Fe3 +–Al3 +-substitution indicating relatively oxidizing conditions of hydrothermal processes. The range of δ11B data for this kind of tourmaline is from − 17.2‰ to − 12.2‰. The hydrothermal tourmaline from felsic porphyry dyke swith gold mineralization has similar crystal chemistry (e.g. dravite–povondraite compositional trend with Fe3 +–Al3 + substitution) and δ11B values between − 19.0‰ and − 9.6‰. The uvite–foitite compositional trend and δ11B ‰ values between − 24.1% and − 13.6% characterize metasomatic–hydrothermal tourmaline from the metasediment-hosted gold deposits. Composition of hydrothermal vein-filling and disseminated tourmaline from the gold-bearing shear zones in metavolcanic rocks is transitional between the felsic intrusion and metasedimentary rock hosted hydrothermal tourmaline but the range of average boron isotope data is essentially identical with that of the metasediment-hosted tourmaline. Rock-forming (magmatic) tourmaline from leucogranite has δ11B values between − 14.5‰ and − 10.8‰ and the major element composition is similar to that of the metasediment-hosted tourmaline.The range of δ34SVCDT values measured in pyrite, chalcopyrite and pyrrhotite is from − 9.1 to + 8.5‰, which falls within the typical range of sulphur isotope data for Archaean orogenic gold deposits. In the Hattu schist belt, positive δ34SVCDT values characterize metasediment-hosted gold ores with sulphide parageneses dominated by pyrrhotite and arsenopyrite. The δ34SVCDT values are both positive and negative in ore mineral parageneses within felsic intrusive rocks in which variable amounts of pyrrhotite are associated with pyrite. Purely negative values were only recorded from the pyrite-dominated gold mineralization within metavolcanic units. Therefore the shift of δ34SVCDT values to the negative values reflects precipitation of sulphide minerals from relatively oxidizing fluids. The range of measured δ65CuNBS978 values from chalcopyrite is from − 1.11 to 1.19‰. Positive values are common for mineralization in felsic intrusive rocks and negative values are more typical for deposits confined to metasedimentary rocks. Positive and negative δ65CuNBS978 values occur in the ores hosted by metavolcanic rocks. There is no correlation between sulphur and copper isotope data obtained in the same chalcopyrite grains.Evaluation of sulphur and boron isotope data together and comparisons with other Archaean orogenic gold provinces supports the hypothesis that the metasedimentary rocks were the major sources of sulphur and boron in the orogenic gold deposits in the Hattu schist belt. Variations in major element and boron isotope compositions in tourmaline, as well as in the δ34SVCDT values in sulphide minerals are attributed to localized involvement of magmatic fluids in the hydrothermal processes. The results of copper isotope studies indicate that local sources of copper in orogenic gold deposits may potentially be recognized if the original, distinct signatures of the sources have not been homogenized by widespread interaction of fluids with a large variety of rocks and provided that local chemical variations have been too small to trigger changes in the oxidation state of copper during hydrothermal processes. 相似文献
12.
Copper and iron skarn deposits are economically important types of skarn deposits throughout the world, especially in China, but the differences between Cu and Fe skarn deposits are poorly constrained. The Edong ore district in southeastern Hubei Province, Middle–Lower Yangtze River metallogenic belt, China, contains numerous Fe and Cu–Fe skarn deposits. In this contribution, variations in skarn mineralogy, mineralization-related intrusions and sulfur isotope values between these Cu–Fe and Fe skarn deposits are discussed.The garnets and pyroxenes of the Cu–Fe and Fe skarn deposits in the Edong ore district share similar compositions, i.e., dominantly andradite (Ad29–100Gr0–68) and diopside (Di54–100Hd0–38), respectively. This feature indicates that the mineral compositions of skarn silicate mineral assemblages were not the critical controlling factors for variations between the Cu–Fe and Fe skarn deposits. Intrusions associated with skarn Fe deposits in the Edong ore district differ from those Cu–Fe skarn deposits in petrology, geochemistry and Sr–Nd isotope. Intrusions associated with Fe deposits have large variations in their (La/Yb)N ratios (3.84–24.6) and Eu anomalies (δEu = 0.32–1.65), and have relatively low Sr/Y ratios (4.2–44.0) and high Yb contents (1.20–11.8 ppm), as well as radiogenic Sr–Nd isotopes (εNd(t) = − 12.5 to − 9.2) and (87Sr/86Sr)i = 0.7067 to 0.7086. In contrast, intrusions associated with Cu–Fe deposits are characterized by relatively high Sr/Y (35.0–81.3) and (La/Yb)N (15.0–31.6) ratios, low Yb contents (1.00–1.62 ppm) without obvious Eu anomalies (δEu = 0.67–0.97), as well as (87Sr/86Sr)i = 0.7055 to 0.7068 and εNd(t) = − 7.9 to − 3.4. Geochemical evidence indicates a greater contribution from the crust in intrusions associated with Fe skarn deposits than in intrusions associated with Cu–Fe skarn deposits. In the Edong ore district, the sulfides and sulfates in the Cu–Fe skarn deposits have sulfur isotope signatures that differ from those of Fe skarn deposits. The Cu–Fe skarn deposits have a narrow range of δ34S values from − 6.2‰ to + 8.7‰ in sulfides, and + 13.2‰ to + 15.2‰ in anhydrite, while the Fe skarn deposits have a wide range of δ34S values from + 10.3‰ to + 20.0‰ in pyrite and + 18.9‰ to + 30.8‰ in anhydrite. Sulfur isotope data for anhydrite and sedimentary country rocks suggest that the formation of skarns in the Edong district involved the interaction between magmatic fluids and variable amounts of evaporites in host rocks. 相似文献
13.
Huseyin Yilmaz Tolga Oyman F. Nuran Sonmez Greg B. Arehart Zeki Billor 《Ore Geology Reviews》2010,37(3-4):236-258
Gold in the Sahinli and Tespih Dere intermediate sulfidation gold-base metal deposits in Western Turkey occurs in relatively deep epithermal quartz veins along with base metal minerals which have epithermal textures, including plumose quartz, vug infills, comb and cockade textures and matrix-supported milled breccias. The total sulfide content of the veins in the area is variable ranging from < 1% to 60% and is dominated by pyrite, galena, sphalerite and chalcopyrite. Sphalerite is Fe-poor (0.6 to 1.4 mol% FeS). Minor amounts of Ag-rich tetrahedrite are present. Primary hydrothermal alteration minerals include illite/muscovite, mixed-layer illite/smectite (11.6 Å) and clinochlore towards the east and, alunite, dickite/nacrite and pyrophyllite towards the west at Sahinli; major illite/muscovite and dickite occur at Tespih Dere and Sarioluk, respectively.Fluid inclusions in main-stage quartz at Sahinli are only liquid-rich, with homogenization temperatures ranging from 220 to 322 °C and the majority of Th values between 250 and 300 °C. Salinity ranges from 4.3 to 6.9 wt.% NaCl equiv. First ice-melting temperatures (Tmf) between ?24.5 and ?19.0 °C indicate that the fluids were dominated by NaCl – H2O during mineralization. The relatively higher average Th at the Tespih Dere deposit (295 °C) is attributed to a relatively deeper level of exposure.Calculated δ18O values indicate that ore-forming hydrothermal fluids in the study area had δ18OH2O ranging from + 1.1 to + 9.7‰ (average = 3.8‰), strongly 18O-enriched compared with present-day hydrothermal meteoric water in the area (δ18O = ?8.5‰). δD values of fluid inclusions in quartz range from ?58 to ?93‰ and δD values of clay minerals and alunite from ?40 to ?119‰. δD values from intermediate argillic alteration (average = ?68‰) in the study area are very similar to δD values of the present-day local geothermal system (average δD = ?54‰) whereas δD values from advanced-argillic alteration (average δD = ?33‰) are very different from the present-day local geothermal system.The δ34S values in samples from the Sahinli and Tespih Dere deposits average ?2.9‰ for pyrite; ?3.3‰ for chalcopyrite; ?5.4‰ for sphalerite and ?7.6‰ for galena. These data are consistent with derivation of the sulfur from either igneous rocks or possibly from local wallrock. 相似文献
14.
This study demonstrates the value of targeted pump and treatment (PAT) to enhance the in situ biodegradation of organic contaminants in groundwater for improved restoration. The approach is illustrated for a plume of phenolic compounds in a sandstone aquifer, where PAT is used for hydraulic containment and removal of dissolved phase contaminants from specific depth intervals. Time-series analysis of the plume hydrochemistry and stable isotope composition of dissolved species (δ34S-SO4, δ13C-CH4, δ13C-TDIC (TDIC = Total Dissolved Inorganic Carbon)) in groundwater samples from high-resolution multilevel samplers were used to deduce changes in the relative significance of biodegradation processes and microbial activity in the plume, induced by the PAT system over 3 years. The PAT system has reduced the maximum contaminant concentrations (up to 6800 mg L−1 total phenols) in the plume by 50% to ∼70% at different locations. This intervention has (i) stimulated in situ biodegradation in general, with an approximate doubling of contaminant turnover based on TDIC concentration, which has increased from <200 mg L−1 to >350 mg L−1, (ii) enhanced the activity of SO4-reducing microorganisms (marked by a declining SO4 concentration with corresponding increase in SO4-δ34S to values >7–14‰V-CDT relative to background values of 1.9–6.5‰V-CDT), and (iii) where the TDIC increase is greatest, has changed TDIC-δ13C from values of −10 to −15‰V-PDB to ∼−20‰V-PDB. This indicates an increase in the relative importance of respiration processes (including denitrification and anaerobic methane oxidation, AMO) that yield 13C-depleted TDIC over fermentation and acetoclastic methanogenesis that yield 13C-enriched TDIC in the plume, leading to higher contaminant turnover. The plume fringe was found to be a zone of enhanced biodegradation by SO4-reduction and methanogenesis. Isotopically heavy methane compositions (up to −47.8‰V-PDB) and trends between δ13C-TDIC and δ13C-CH4 suggest that AMO occurs at the plume fringe where the contaminant concentrations have been reduced by the PAT system. Mass and isotope balances for inorganic carbon in the plume confirm the shift in spatial dominance of different biodegradation processes and significant increase in contribution of anaerobic respiration for contaminant biodegradation in zones targeted by the PAT system. The enhanced in situ biodegradation results from a reduction in organic contaminant concentrations in the plume to levels below those that formerly suppressed microbial activity, combined with increased supply of soluble electron acceptors (e.g. nitrate) into the plume by dispersion. An interruption of the PAT system and recovery of the dissolved organic contaminant concentrations towards former values highlights the dynamic nature of this enhancement on restoration and relatively rapid response of the aquifer microorganisms to changing conditions induced by the PAT system. In situ restoration using this combined engineered and passive approach has the potential to manage plumes of biodegradable contaminants over shorter timescales than would be possible using these methods independently. The application of PAT in this way strongly depends on the ability to ensure an adequate flux of dissolved electron acceptors into the plume by advection and dispersion, particularly in heterogeneous aquifers. 相似文献
15.
The Xiaguan Ag–Pb–Zn orefield (Neixiang County, Henan Province), hosting the Yindonggou, Zhouzhuang, Yinhulugou and Laozhuang fault-controlled lode deposits, is situated in the Erlangping Terrane, eastern Qinling Orogen. The quartz-sulfide vein mineralization is dominated by main alteration styles of silicic-, sericite-, carbonate-, chlorite- and sulfide alteration. Major Ag-bearing minerals are freibergite, argentite and native Ag. The deposits were formed by a CO2-rich, mesothermal (ca. 250–320 °C), low-density and low salinity (< 11 wt.% NaCl equiv.), Na+–Cl−-type fluid system. Trapping pressures of the carbonic-type fluid inclusions (FIs) decreased from ca. 280–320 MPa in the early mineralization stage to ca. 90–92 MPa in the late mineralization stage, indicating that the ore-forming depths had become progressively shallower. This further suggests that the metallogenesis may have occurred in a tectonic transition from compression to extension. Geological- and ore fluid characteristics suggest that the Xiaguan Ag–Pb–Zn orefield belongs to orogenic-type systems.The δ18OH2O values change from the Early (E)-stage (7.8–10.8 ‰), through Middle (M)-stage (6.0–9.4 ‰) to Late (L)-stage (− 1.5–3.3 ‰), with δD values changing from E-stage − 95 to − 46 ‰, through M-stage − 82 to − 70 ‰ to L-stage − 95 to − 82 ‰. δ13CCO2 values of the ore fluids in the E- and M-stage quartz vary between 0.1 ‰ and 0.9 ‰ (average: 0.3 ‰); δ13CCO2 values of L-stage FIs are − 0.2–0.1 ‰ in quartz and − 6.8 ‰ to − 3.5 ‰ in calcite. The H–O–C isotopic data indicate that the initial ore fluids were sourced from the underthrusted Qinling Group marine carbonates, and were then interacted with the ore-hosting Erlangping Group metasedimentary rocks. Inflow of circulated meteoric water may have dominated the L-stage fluid evolution.Sulfur (δ34S = 1.9–8.1 ‰) and lead isotopic compositions (206Pb/204Pb = 18.202–18.446, 207Pb/204Pb = 15.567–15.773 and 208Pb/204Pb = 38.491–39.089) of sulfides suggest that the ore-forming materials were mainly sourced from the ore-hosting metasedimentary strata. The stepped heating sericite 40Ar/39Ar detection suggests that the mineralization occurred in the Middle Jurassic to Early Cretaceous (ca. 187 − 124 Ma). Considering the regional tectonic evolution of the Erlangping Terrane, we propose that the Xiaguan Ag–Pb–Zn orefield was formed in a continent–continent collisional tectonic regime, in accordance with the tectonic model for continental collision, metallogeny and fluid flow (CMF). 相似文献
16.
《Sedimentary Geology》2006,183(1-2):51-69
The Chicxulub Sedimentary Basin of the northwestern Yucatan Peninsula, Mexico, which was formed because of the largest identified Phanerozoic bolide impact on Earth, became a site of deposition of dominantly marine carbonate sediments during most of the Cenozoic Era. This is a study of the filling and diagenetic history of this basin and surrounding areas. The study makes use of lithologic, biostratigraphic, petrographic, and geochemical data obtained on core samples from boreholes drilled throughout the northwestern Yucatan Peninsula.The core sample data indicate that: 1) The Chicxulub Sedimentary Basin concentrated the deposition of pelagic and outer-platform sediments during the Paleocene and Eocene, and, in places, during the Early Oligocene, as well, and filled during the Middle Miocene, 2) deeper-water limestone also is present within the Paleocene and Lower Eocene of the proposed Santa Elena Depression, which is located immediately south of the Basin, 3) shallow-water deposits are relatively more abundant outside the Basin and Depression than inside, 4) the autigenic and allogenic silicates from the Paleogene formations are the most abundant inside the Depression, 5) sediment deposition and diagenesis within the Basin also were controlled by impact crater topography, 6) the abundance of the possible features of subaerial exposure increases upward and outward from the center of the Basin, and 7) the formation of replacive low-magnesium calcite and dolomite, dedolomitization, dissolution, and precipitation of vug-filling calcite and dolomite cement have been more common outside the Basin than inside.δ18O in whole-rock (excluding vug-filling) calcite from core samples ranges from − 7.14‰ to + 0.85‰ PDB. δ13C varies from − 6.92‰ to + 3.30‰ PDB. Both stable isotopes correlate inversely with the abundance of subaerial exposure features indicating that freshwater diagenesis has been extensive especially outside and at the edge of the Chicxulub Sedimentary Basin.δ18O and δ13C in whole-rock (excluding vug-filling) dolomite ranges from − 5.54‰ to + 0.87‰ PDB and − 4.63‰ to + 3.38‰ PDB, respectively. Most dolomite samples have negative δ18O and positive δ13C suggesting that replacive dolomitization involved the presence of a fluid dominated by freshwater and/or an anomalously high geothermal gradient.Most dolomite XRD-determined mole percent CaCO3 varies between 51 and 56. Replacive dolomite is larger, more euhedral, and less stoichiometric inside the Chicxulub Sedimentary Basin than outside. 相似文献
17.
The Hoshbulak Zn–Pb deposit is located in South Tianshan, Xinjiang, China. The Zn–Pb orebody is tabular and stratoid in form and it is hosted in calcareous rocks of the Upper Devonian Tan'gaitaer Formation which were thrust over the Carboniferous system. The ores are mineralogically simple and composed mainly of sphalerite, galena, pyrite, calcite, dolomite and exhibit massive, banded, veinlets, colloidal, metasomatic, eutectic, concentric ring and microbial-like fabrics. The Co/Ni ratios of pyrite in the ores range from 0.46 to 0.90 by electron microprobe, which suggested that the Hoshbulak Zn–Pb mineralization was formed in a sedimentary environment. The REE patterns of the hydrothermal calcite coincide well with those of recrystallized micritic limestones, suggesting that the Hoshbulak Pb–Zn mineralization was closely genetically related to limestones of the Tan'gaitaer Formation. The C-, H- and O-isotopic compositions of hydrothermal calcite and dolomite in the ores yield δ13C(VPDB) values ranging from − 1.9‰ to + 2.6‰ (mean 0.79‰), δ18O(VSMOW) values from 22.41‰ to 24.67‰ (mean 23.04‰) and δD values from − 77‰ to − 102‰ for fluid inclusions. It is suggested that the ore-forming fluids, including CO2, were derived from the calcareous strata of the Tan'gaitaer Formation in association with hydrocarbon brines. The δ34S(VCDT) ranges from − 22.3‰ to − 8.5‰ for early ore-stage sulfides and from 5.9‰ to 24.2‰ with a cluster between 14.4‰ and 24.2‰ for the sulfides (pyrite, sphalerite, galena) in the main ore-stage. The ore sulfur may have been derived from evaporite rocks by thermochemical sulfate reduction (TSR) as the predominant mechanism for H2S generation. The Pb-isotopic compositions of the sulfide minerals from the Hoshbulak ores yield 206Pb/204Pb ratios from 17.847 to 18.173, 207Pb/204Pb ratios from 15.586 to 15.873 and 208Pb/204Pb ratios from 37.997 to 38.905, which indicate that the metals were sourced mainly from the Tan'gaitaer Formation. We conclude that the genesis of the Hoshbulak Mississippi Valley-type deposit was closely related to thrust faulting in the South Tianshan orogen of China. 相似文献
18.
A new noble metal-graphite mineralization has been revealed in the Ruzhino amphibolite-facies rocks of the northern Khanka block. It is characterized by Au and PGE (platinum group elements) contents (up to tens g/t, Pt > Au) as high as those in world-class deposits hosted by sedimentary and magmatic rocks, but is distinguished from them by isotopic composition of carbon, hydrogen and oxygen, all suggesting a distinct mantle contribution (δ13СVPDB from − 8.5 to − 10.5‰ in graphite, δDVSMOW from − 82.5 to − 106.7‰ and δ18OVSMOW from 8.2 to 10.1‰ in biotite). The Ruzhino-type mineralization is highly resistant to common chemical treatments, so that detection of their metals requires that some special methods be developed. Atomic Absorption Spectrophotometry and Inductively Coupled Plasma Mass Spectrometry following severe chemical treatments and ignition at 600–650 °C, as well as Ion Mass Spectrometry allowing a direct detection of elements in solid materials were employed in this study. These methods increased noble-metal contents of the graphitized rocks compared to standard analyses including a conventional fire assay. In addition, electron microscopy surveys discovered extremely diverse native-metal and intermetallic complexes with C, O, Cl, F, REE and other elements. The microinclusions, however, represent a minor part of the mineralization. Major constituents seem to form carbonaceous nanocompounds invisible under a microscope. These graphite-based nanocomplexes, which are especially developed in the case of Pt, seem to be responsible for the highly resistant character of the Ruzhino mineralization. They also may be present in the latent form among the common Au ± PGE ores hosted by carbonaceous shales like those we studied in the close vicinity of the Ruzhino amphibolite-facies rocks and in the northeastern Bureya–Jiamusi terrane. 相似文献
19.
The skarn type copper deposits are widespread in the Jiurui district in the Middle-Lower Yangtze River metallogenic belt. This paper reports a detailed study on mineral chemistry, and H, O, S and Pb isotopic compositions on skarn silicate and sulfide minerals in the three major skarn dominant deposits (Wushan, Dongleiwan and Dengjiashan). The Wushan skarn deposit is characterized with prograde garnet-dominated and clinopyroxene limited skarns with average andradite content of 83% and hedenbergite content of 10%, whereas the Dongleiwan and Dengjiashan deposits are featured with retrograde skarn alteration with abundant hydrous minerals such as epidote and chlorite. The garnet and clinopyroxene compositions show 59% andradite and 15% hedenbergite for the Dongleiwan skarns, and 43% and 22% for the Dengjiashan skarns respectively. The pistacite components (Ps value) defined as Fe3 +/(Fe3 ++ Al) and Fe3 +/Fe2 + value of epidote are 0.12 and 1.63 for the Wushan skarns, 0.30 and 32.73 for the Dongleiwan skarns, and 0.17 and 42.85 for the Dengjiashan skarns. It is suggested that the prograde skarn mineralization in the three deposits was all formed in a relatively oxidizing environment, with the Wushan showing the highest oxidation potential and the Dengjiashan having the least oxidation potential. However, in the retrograde skarns, the Dongleiwan and Dengjiashan deposits show higher oxidation potential than that of Wushan. The three deposits show similar sulfur isotopic compositions of − 2.9 to + 1.4‰ and similar lead isotopic compositions with 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of 17.900 to 18.205, 15.538 to 15.649 and 38.170 to 39.025, respectively. All the three deposits should have similar magmatic origin for the ore-forming materials based on their S and Pb isotopes. The oxygen isotopic compositions of the prograde and retrograde fluids in the three deposits show some differences, with δ18OFluid values of + 8.13‰ and + 7.81‰ for the Wushan, + 6.47‰ and + 2.33‰ for the Dongleiwan, and + 8.27‰ and + 4.43‰ for the Dengjiashan. But the hydrogen isotopic compositions are similar for the prograde (− 65 to − 31‰) and retrograde (− 64 to − 33‰) fluids. Therefore, the fluid origins and evolution may be different in each deposit. The hydrothermal fluids for the prograde skarns in all three deposits were likely derived from magmatic–hydrothermal sources, but the Dongleiwan and Dengjiashan show a higher proportion of meteoric water input in the retrograde stage. Considering the similar average prograde temperatures (574 to 560 °C) as calculated from coexisting garnet–clinopyroxene pairs, and similar retrograde temperatures (281 to 246 °C) as calculated from chlorite chemistry for the three deposits, we suggest that the trigger for deposition of sulfide ores in the Wushan garnet-dominated skarn deposit was mainly caused by system cooling with temperature drop along with magmatic intrusion and crystallization process. The Dongleiwan and Dengjiashan skarn deposits constitute a well developed retrograde skarn system with abundant epidote, chlorite, quartz and calcite, which probably caused by fluid mixing of high-temperature saline magmatic–hydrothermal fluids with cooler, oxidizing and dilute meteoric water. 相似文献
20.
Two epithermal gold deposits (Kartaldağ and Madendağ) located in NW Turkey have been characterized through the detailed examinations involving geologic, mineralogical, fluid inclusion, stable isotope, whole-rock geochemistry, and geochronology data.The Kartaldağ deposit (0.01–17.65 ppm Au), hosted by Eocene dacite porphyry, is associated with four main alteration types with characteristic assemblage of: i) chlorite/smectite–illite ± kaolinite, ii) quartz–kaolinite, iii) quartz–alunite–pyrophyllite, iv) quartz–pyrite, the last being characterized by three distinct quartz generations comprising massive/vuggy (early), fine–medium grained, vug-lining (early), and banded, colloform, comb (late) textures. Observed sulfide minerals are pyrite, covellite, and sphalerite. Oxygen and sulfur isotope analyses, performed on quartz (δ18O(quartz): 7.93 to 8.95‰ and calculated δ18O(H2O): − 7.95 to 1.49‰) and pyrite (δ34S(pyrite): − 4.8‰ and calculated δ34S(H2S): − 6.08 to − 7.20‰) separates, suggest a meteoric water source for water in the hydrothermal fluid, and an igneous source for the sulfur dissolved in ore-related fluids. Microthermometric analyses of primary fluid inclusion assemblages performed on quartz (late quartz generation) yield temperatures (Th) dominantly in the range of 245–285 °C, and generally low salinity values at 0 to 1.7 wt.% NaCl eq. Based on the quartz textures and the associated base metal concentrations, along with fluid inclusion petrography, the early vug-lining quartz is considered to have been associated with the mineralization possibly through a boiling and a late mixing process at > 285 °C.The Madendağ deposit (0.27–20.60 ppm Au), hosted by Paleozoic mica schists, is associated with two main alteration types: sericite–illite–kaolinite, and quartz–pyrite dominated by two distinct quartz generations i) early colloform, comb and banded quartz and ii) late quartz, forming the cement in hydrothermal breccia. Whereas oxygen isotope analyses of quartz (δ18O(quartz): 9.55 to 18.19‰ and calculated δ18O(H2O): − 2.97 to 5.54‰) suggest varying proportions of meteoric and magmatic sources for the ore bearing fluid, sulfur isotope ratios (δ34S(pyrite): − 2.2‰ and calculated δ34S(H2S): (− 3.63) to (− 3.75) ‰) point to an essentially magmatic source for sulfur with or without contribution from sedimentary sources. Microthermometric analysis carried out on primary fluid inclusion populations of a brecciated sample (early quartz), give a temperature (Th) range of 235–255 °C and 0.0 to 0.7 wt.% NaCl eq. salinity. Based on the textural relationship, base metal and high gold contents, the ore precipitation stage is associated with late stage quartz formation via a possible boiling process.The presence of alunite, pyrophyllite and kaolinite, vuggy quartz and covellite suggest a high-sulfidation type of epithermal deposit for Kartaldağ. On the other hand, Madendağ is identified as an adularia-sericite type owing to the presence of significant sericite, neutral pH clays (mostly illite, chlorite/smectite, and kaolinite), low temperature quartz textures (e.g., colloform, comb, and banded quartz), and limited sulfide minerals.Given the geographical proximity of Kartaldağ and Madendağ deposits, the similar temperature and salinity ranges obtained from their fluid inclusions, and the similar ages of igneous rocks in both deposits (Kartaldağ: 40.80 ± 0.36 to 42.19 ± 0.45 Ma, Madendağ: 43.34 ± 0.85 Ma) the mineralizing systems in both deposits are considered to be genetically related. 相似文献