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The volcanic complex of North Khour located in southern Khorasan province, 90 km northwest of Birjand in the Eastern of Iran. The rocks under study are basaltic andesite, andesite and trachyandesite, latite, dacite to rhyodacite with tuff and breccia as pyroclastic rocks. The volcanic rocks are predominantly calc-alkaline nature with some tholeiitic affinity and porphyry texture. Iron mineralization developed as magnetite, hematite and small amount of goethite with magmatic origin, on the base of field observations. Bornite as the only and the primary Cu ore occurred as a small body. The presence of minor amounts of bornite and pyrite as the sulfide phases as well as the absence of the other Cu primary sulfide ores in the area along with secondary Cu mineralization phases reflect a hydrothermal solution with high oxidation degree which has passed the latest magmatic differentiation and gave rise to form surface Cu ores as chalcocite in supergene zone. The thermobarometry of fluid inclusions studies from Ghar Kaftar and Hoze Sabz, yield temperature range of 178 -324 C for Cu mineralization. Therefore, it seems that Cu mineralization is related to epithermal to mesothermal conditions. [ABSTRACT FROM AUTHOR]

The Gheshlagh Cu deposit is located in the Tarom-Hashtjin metallogenic belt (THMB) of northwest Iran. The mineralization is hosted by Eocene volcanic and volcaniclastic rocks of the Karaj Formation at the subduction-related magmatic arc position. Wall rock alterations include propilitization, silicification, and carbonatization. The major copper sulfides are pyrite, chalcopyrite, chalcocite, idaite, bornite, covellite, and digenite associated mainly with hydroxide carbonate (malachite), oxide (hematite, magnetite, and goethite), and native copper that show open space filling, disseminated, vein-veinlet, and replacement textures. Commonly mineralization and alteration are structurally controlled by favorable structures (faults and fracture). Based on crosscutting, the relationship of vein, textural relationship, mineral assemblage, and fluid inclusion microthermometry, it was found that alteration and mineralization in the Gheshlagh ore deposit occurred in the fourth main stage. The first stage (stage I) is accompanied by the formation of pyrite (discontinuous) under reducing conditions in the seafloor and very shallow burial. During the increase of the burial depth (stage II), sediments have hardened, and also tectonic and lithostatic stress, dykes, and floods cause intraformational and magmatic fluid circulation by compaction and heat recharging. These high-temperature fluids are enriched in copper during circulation among volcanic units. Copper-rich fluids migrate upward and are reduced by entering the pyrite-rich andesitic-basaltic unit, and copper is deposited in sulfide forms such as chalcopyrite and chalcocite in favorable site. In deep burial (stage III), the copper mineral formed in the previous stage would be replaced by. At the supergene condition (stage IV), due to oxidizing conditions, weathering, and leaching, copper sulfides mostly appear as malachite in the joints and voids. [ABSTRACT FROM AUTHOR]

Varmazyar Pb–Zn (Ag) occurrence, 65 km north of Zanjan, is located in the Tarom–Hashtjin metallogenic belt (THMB). The THMB has been recognized to be one of the most important epithermal metallogenic belts in Iran (Kouhestani et al., 2018b). It hosts numerous small- to medium-sized epithermal deposits (i.e., Gulojeh, Aqkand, Aliabad– Khanchy, Chodarchay, Khalyfehlou, Chargar, Zajkan, Marshoun, Abbasabad, Zehabad, and Shah Ali Beiglou). These epithermal deposits are temporally and spatially related to late Eocene granitoids (Mehrabi et al., 2016; Kouhestani et al., 2018b). Although the general geological characteristics of the region, where the Varmazyar occurrence is located, have been already determined (Faridi and Anvari, 2000), no detailed studies have been conducted on its mineralogy, geochemistry, and characteristics of the ore-forming fluids of the Varmazyar occurrence. In this paper, we investigate the geology, mineralogy, geochemistry, fluid inclusions, and alteration styles of the Varmazyar occurrence to constrain its ore genesis. These results may have implications for the regional exploration of epithermal deposits in the THMB. [ABSTRACT FROM AUTHOR]

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The Tagun‐Khin‐Dan gold deposit in the Mogok‐Mandalay‐Mergui Belt, Central Myanmar, is characterized by an array of quartz‐veins hosted in mudstone of the Kogwe Formation of the Carboniferous Mergui Group. Two major deformational stages were recorded in the area; (1) N‐S shortening and (2) uplifting and emplacement of various dykes and quartz veinlets. The N‐S shortening within the area lead the development of km‐scale faults, determined largely by the presence of a zone of major WNW‐ESE trending dextral strike‐slip faulting. Quartz veins in the deposit include: (1) type‐A quartz veins, parallel to the dextral NW‐SE trending major fault; and (2) type‐B quartz veins which occur as isolated parallel veins. Gold in the type‐A quartz vein is present as native gold and electrum locked within pyrite and associated with pyrite and galena and in the type‐B quartz veins as electrum associated with sulfide minerals such as pyrite, chalcopyrite, galena and sphalerite. The mineralization stages can be classified into the type‐A quartz vein stage and the type‐B quartz vein stage. Two type of fluid inclusions; liquid‐rich aqueous inclusions (L‐type) and vapor‐rich aqueous inclusions (V‐type) are identified in the type‐A quartz veins. The homogenization temperature of L‐type fluid inclusions of the type‐A quartz veins ranges from 203 to 321°C and salinity of the fluid inclusions varies from 0.4 to 1.6 wt% NaCl equiv. The homogenization temperature of V‐type fluid inclusions of type‐A quartz veins ranges from 290 to 340°C with a salinity ranging from 0.4 to 1.9 wt% NaCl equivalent. In the type‐B quartz veins, only liquid‐rich aqueous inclusions (L‐type) are identified. The type‐B quartz veins yielded low homogenization temperatures from 160 to 220°C, with low salinities from 0.2 to 1.9 wt% NaCl equiv. compared with those of the type‐A veins. The depth range of ore formation is estimated to be a shallow depth of less than 0.2 km based on fluid inclusion microthermometry. Fluid boiling is evident during the type‐A quartz vein stage, and fluid cooling and mixing in the later type‐B quartz vein stage. Precipitation of pyrite in the ore zone occurred as four recognized types: arsenic‐rich pyrite‐1, 2, 3 in the type‐A quartz veins and pyrite‐4 in the type‐B quartz veins. A positive relation between Au and As contents of pyrites suggests that the gold is present together with arsenic in the structure of pyrites of the type‐A quartz veins as solid solution in addition to as nanoparticle inclusions. The high Co and Ni contents of pyrites of both the type‐A and the type‐B quartz veins, with no evidence of CO2 in the system indicate that the ore‐forming fluids were epizonal magmatic‐hydrothermal fluids rather than metamorphic fluid. The hydrothermal fluids of the Tagun‐Khin‐Dan deposit were driven by faulting to form the mudstone‐hosted epithermal gold mineralization and related to continuing northwards movement of the Indian Plate that initiated the displacement on the strike‐slip Sagaing Fault. [ABSTRACT FROM AUTHOR]

The Northeast Japan arc hosts a number of hydrothermal vein‐type copper deposits associated with Neogene felsic intrusions. The Arakawa area is underlain by Cretaceous granites and Tertiary sedimentary rocks, which were intruded by the Miocene Ushizawamata dacite. Zircon grains from the dacite intrusion yield a 206Pb/238U intercept age (laser ablation inductively coupled plasma mass spectrometry) of 8.10 ± 0.30 Ma, consistent with a previously reported K‐Ar illite age (8.1 ± 0.4 Ma) of the Ushizawamata lead and zinc prospect in the Arakawa area. The dacite intrusion and the surrounding Miocene sedimentary rocks were altered by hydrothermal activity on the surface, classified into four alteration zones: (1) biotite‐chlorite, (2) illite, (3) chlorite and (4) smectite, centered on the intrusion. About 20 major vertical sub‐parallel copper‐bearing quartz veins occur in the chlorite alteration zone on the west side of the dacite. The first vein stage is composed of chalcopyrite and chamosite with a minor amount of quartz in brecciated wall rocks, and the second‐stage is characterized by the presence of hematite in addition to the first‐stage mineral assemblage. The third‐stage consists of comb‐shaped quartz veins with a minor amount of chalcopyrite, sphalerite, galena and pyrite, and the fourth‐stage of barite and apatite present in druse in the third‐stage veins. Primary fluid inclusions in quartz of the first‐ and third‐stages are all liquid‐rich and two‐phase. Homogenization temperature and salinity of first‐stage quartz are 263–277°C and 5.7–7.5 wt% NaCl equivalent (eq.); in quartz of the third‐stage, 251–270°C and 2.7–4.2 wt% in the inner zone and 207–250°C and 2.7–3.7 wt% in comb‐shaped quartz on the vein margin. The fluid inclusions in quartz phenocrysts of the Ushizawamata dacite show two distinct assemblages, halite‐bearing polyphase inclusions that coexist with vapor‐phase inclusions and/or vapor‐rich two‐phase inclusions, and liquid‐rich two‐phase inclusions. Homogenization temperature and salinity of the polyphase inclusions are higher than 401°C and 46.7 wt%, respectively, and those of the vapor‐rich two‐phase inclusions report 393–419°C and 2.6–3.7 wt% NaCl, whereas the liquid‐rich two‐phase inclusions returned 344–403°C and 8.0–9.3 wt%, respectively. These results indicate that the ore forming fluid was slightly cooler and lower in salinity than the late‐stage hydrothermal fluid in the Ushizawamata intrusion. The spatial and temporal proximity between the Ushizawamata dacite and the hydrothermal veins indicates that the dacitic magma was genetically related to the vein copper mineralization in the Arakawa area. [ABSTRACT FROM AUTHOR]

Interpretation of various exploration data, in particular geochemical prospecting, offers a powerful and rapid assessment of grass‐root projects in a green‐field terrain. Here, we present an example of the Collins epithermal prospect in Aceh Province, Indonesia. In this area, the Au+ base‐metal‐bearing sheeted quartz veins (individually mostly 2–4 cm wide), which are controlled by a 250 m wide by 800 m long NNE‐trending structural corridor within Paleogene sandstone and volcanic rocks, are the product of two main stages of deposition. Stage I formed veins with a sliver of cryptocrystalline quartz wall zone followed by an inner zone of comb quartz with interstitial rhombic adularia that terminates in open space. Stage I or main‐stage sulfide mineralization consisting of early galena + sphalerite and later chalcopyrite occurs with the quartz + adularia. Small amounts of galena also occur in the wall zone. Stage II mineralization brecciated Stage I veins and overprinted them with silicification characterized by vuggy texture. Mineralization associated with this episode consists of earlier chalcopyrite + sphalerite + tennantite–tetrahedrite and later, vug‐filling Au–Ag alloy (Ag0.37–0.41Au0.62–0.59). The above mineralized veins are successively flanked by silicic selvages, an illite + chlorite + pyrite ± kaolinite zone and a chlorite + epidote + carbonate + pyrite zone. Local supergene alteration induced replacement of galena by plumbogummite and anglesite and chalcopyrite by covellite. Data from fluid inclusion microthermometry in quartz indicated that the inner zone of Stage I veins formed from fluids with a 2.3 wt% salinity (0.5–3.3 wt% NaCl equivalent), at 174°C (155–211°C). Combining these physico‐chemical parameters with the mineral assemblage, the mineralization occurred under a reduced environment. Rock and soil assays indicate that elevated Au concentrations (up to 16.5 ppm over 1 m) occur along northeast‐trending zones and show a strong correlation with Pb, while Cu (up to 2.58% over 1 m), Zn, As, Sb, and Mo anomalies lie mostly at the periphery. The high‐grade mineralized veins correlate with moderate to high resistivity and chargeability zones, and the pseudosections of such geophysical signals are interpreted as reflecting coalesced or enlarged veins at depth, or inclined veins in other localities. The intermediate sulfidation affinity for Collins points to potential mineralization at depth as well as preservation of Au‐rich and sulfide‐poor zones in the less eroded areas. [ABSTRACT FROM AUTHOR]

The study area is located in the southeastern Biga Peninsula. As result of field, drilling and laboratory studies, diorite porphyry intruded to Lower Miocene and older units and contained Au, Pb, Zn and Cu anomalies, has been determined. Intersected potassic, propylitic, phyllic and argillic alteration zones were developed in the pluton and host rock. Veins-veinlets developed in the pluton and host rock, contain native gold, silver, pyrite, chalcopyrite, sphalerite and galena. They are composed of undulated quartz in the deeper levels, and massive quartz, calcite/dolomite and barite in the middle and upper levels. According to the fluid inclusion data from sphalerite, quartz and barite, temperature of ore-bearing fluids are in three groups (argillic:150-220°C, phyllic:250-350°C, potassic:>400°C). Fluid inclusions, including solid phases such as hematite, chalcopyrite and salt as well as liquid and gas phases, indicate that Çatalçam Au-Cu mineralization is intrusion-related system. Fluid inclusion data display temperature and salinity of the ore-bearing fluids in the early stage (porphyry) are high, whereas relatively lower in the late stage (epithermal). In conclusion, Çatalçam mineralization was developed in two different phases as porphyry Au-Cu and epithermal Zn-Pb-Cu-Au, which is the first porphyry gold deposit related to Miocene magmatic-hydrothermal system in the Biga porphyry belt. [ABSTRACT FROM AUTHOR]

The Lower Paleozoic reservoir in the Micangshan tectonic zone is a new shale gas exploration area with excellent potential. However, the hydrocarbon migration and accumulation histories of this reservoir have not been thoroughly elucidated and urgently require further research. Fluid inclusions offer a unique and useful method to test for hydrocarbon migration, accumulation, composition and timing. This study integrated the hydrocarbon charge history using fluid inclusions in the Lower Cambrian to Neoproterozoic reservoir from the Micangshan tectonic zone. This work involves the delineation and analysis of fluid inclusions using the petrography, spectroscopy and microthermometry of fluid inclusions. Based on the fluid inclusion analyses combined with reservoir thermal history, timing estimates and charge models of the hydrocarbons were obtained. The formation of natural gas was multifactorial in the Lower Cambrian to Neoproterozoic petroleum system, and the gas in the Niutitang (ϵ1n) and Dengying (Z2d) reservoirs was mainly from oil cracking and dry gas, and gas in the Xiannvdong (ϵ1x) and Canglangpu (ϵ1c) reservoirs was abiogenic and formed in hydrothermal fluids by regional tectonothermal events. Three well-defined stages of hydrocarbon charge were identified in the petroleum system in the Micangshan tectonic zone. The stage of oil charge first began before the Early Permian (∼277 Ma); the stage of gas charge from oil cracking occurred in the Late Triassic to Early Jurassic (212 Ma-198 Ma); and the stage of gas charge from dry gas occurred in the Middle Jurassic (173 Ma-166 Ma). The gas of mixed origin from the Niutitang reservoir was stored in the nanoscale pores as a self-reservoir, rather than as an effective gas source for the overlying reservoirs.

Introduction The study area is located in the Khorasan Razavi Province, NW of Gonabad between 58° 33˝- 58 ° 38˝ to the east and 25° 34˝ - 25° 38˝ to the north. Geotectonically, the area is located in the northern part of the Lut Block. The Lut Block is the main metallogenic province in the east of Iran (Karimpour et al., 2012). There is a significant outcrop of Tertiary intermediate volcanic and pyroclastic rocks in the northwest of Gonabad. This region is rich in clay (kaolin) mineralization. The source of these kaolin deposits (argillic alteration) is related to a granitic dyke that intruded into the Shemshak Formation. Geology According to studies most of the rocks in this region are volcanic rocks which mainly consist of trachyte, andesite, trachyandesite, dacite, rhyodacite, pyroclastics rocks of agglomerate and tuff and some subvolcanic masses and dykes of acidic to intermediate compositions. Sedimentary rocks in the study area are slightly metamorphosed. The oldest metamorphic rock is exposed in the south- east of the study area which consists of Jurassic slates and quartzite. At this area green schist facies have led to the formation of slate and quartzite. The intrusive bodies, composition are monzogranite porphyry to diorite porphyry. The main fault zones which make specific types of structure are strike-slip. Alteration and mineralization The volcanic and subvolcanic rocks have been affected by hydrothermal fluids via the phenomenon which has caused alteration in the rocks. The alteration zones are propylitic, silicification, argillic, and quartz-sericite-pyrite. The silicification has occurred with higher intensity in the northern and central parts of the investigated area. Propylitic alteration has spread all over the area with higher intensity in the northwest and southern parts of the study area. The clay mineral deposits (argillic zones) have been mined. The mineralogical compositions of this clay deposits are quartz, kaolinite, dickite, montmorillonite and hematite. Materials and Methods Ten doubly polished wafers (0.3mm thick) of fluorite, barite and quartz crystals were prepared for fluid inclusion studies, and examined petrographically. They were studied using standard techniques (Roedder, 1984, 1992) and Linkam THM 600 heating–freezing stage (from -190 to 600 °C) mounted on an Olympus TH4–200 microscope stage at the Ferdowsi University of Mashhad, Iran. The accuracy is estimated to be ±0.2 °C on freezing, ±2 °C below 350 °C and about ±4 above 350 °C on heating. The salinity of the fluids trapped in fluid inclusions is calculated based on the temperature of final ice melting (Tm) and the equation of Bodnar (1993). Densities are calculated using the Flincor software according to microthermometric data (Brown and Lamb, 1989). Discussion Microthermometeric investigations were conducted on 126 fluid inclusions in two types of liquid-rich (L+V) fluids in silicified cap of Rokhsefid and Baghsia kaolin mines. Homogenization experiments revealed a temperature range of 186–326 °C for the studied inclusion. Salinity variations could not be determined because of the small amount of fluids. The homogenization temperature and depth of formation from the first type of inclusions are 186- 256°C and 250 meters, respectively. The second type of inclusions have Th between 275 to 326°C and are 500 meter in depth. Microthermometric study of fluid inclusions on quartz-sericite-pyrite and sulfide- silicified mineralization in Kalatehno indicates that two types of hydrothermal fluids were important in the formation of mineralization. These two types are involved. First, Th between 289- 354 °C, salinity range from 10.86 to 10.98 wt.% NaCl equivalent, and the average depth of about 600 meters. Second, Th between 266- 377°C, salinity ranges from 11.7 to 13.07 wt.% NaCl equivalent, and average depth of about 600 meters. Microthermometric study of the fluid inclusions in fluorite veins were conducted on fluorite, barite and quartz minerals. The results obtained from the fluorites indicate Th between 184- 360°C, and Salinity ranges from 0 to 3.2 wt.% NaCl equivalent. Fluid inclusion studies consisting of quartz veins and quartz- sulfide- copper carbonate in Kalatehno copper mineralization involve two types of fluids with homogenization temperatures and salinity range from 260- 300 °C and 1.5- 3.23 wt.% NaCl equivalent and 193- 240 °C and 4.1- 5.86 wt.% NaCl equivalent. Conclusion Fluid inclusion studies on fluorite samples have shown a temperature homogenizations (Th) between 186-326 °C. These studies indicate the average formation temperature of 280°C for argillic alteration. Fluid inclusion studies on Kalateno Cu mineralization show two types of mineralization fluids with the temperatures of 193 to 240 and 260 to 300°C with salinity between 1.5-3.23 wt. % 4.1- 5.86 wt.% NaCl equivalent, respectively. The temperature ranges obtained are similar to those of epithermal systems.

Introduction The Robaie copper area is located 95 kilometers South of Damghan in the Semnan province. The study area has coordinates between 54˚30΄37˝to 54˚30΄42.71˝ latitude and 35˚22΄29.41˝ to 35˚23΄47.54˝ longitude. Geotectonically, the study area is located in the central Iran and in the northern part of the Torud-Chahshirin volcanic-plutonic belt (Houshmandzadeh et al., 1978). The Torud-Chahshirin volcanic-plutonic belt is a Tertiary magmatism in central Iran which is composed of volcanic rocks with dominant andesite composition and granodiorite intrusive with dominant diorite composition (Fard et al., 2001). Torud-Chahshirin volcanic-plutonic belt has created a favorable geological situation for base metals such as copper, lead, zinc, gold, silver and other precious and base metals, such as the Robaie copper area, Chah Messi (Cu±Pb-Zn; Imamjome et al., 2009), Kuh-Zar (Cu-Au; Rohbakhsh et al., 2018) and other instances. The main objective of this study is geology, petrography, U-Pb zircon dating and Sr-Nd isotope and also alteration, mineralization, geochemistry and fluid inclusion in the study area. Materials and methods 60 samples were collected from the study area. Petrographic studies were done on 40 thin sections. Mineralization and paragnesis of the system were studied based on 10 polished-thin sections and 6 polished sections. The measurements were conducted on a Linkam THMSG 600 at the Ferdowsi University of Mashhad. REE (ICP-MS method-ACME Laboratory in Vancouver, Canada) elements were analyzed for 3 samples of diorite dykes. Eight sampels for geochemistry and four samples for fire assay were analyzed at the Zar Azma Company. U-Pb dating in zircon of diorite dyke was conducted by the ICP-MS method in the Arizona LaserChron Center. Sr and Nd isotopic compositions were determined at the Laboratório de Geologia Isotópica da Universidade de Aveiro, Portugal. Results The geology of the area is dominated by volcanic rocks (andesite and trachyandesite), which were intruded by diorite dykes. Alteration zones are propylitic, argillic, sericitic and carbonate. The Copper deposit in the study area occurs as ore veins situated along fault zone with NS-SW trending. Vein thickness varies from 1-5m. Vein thickness varies from 1-5m. The primary minerals are chalcopyrite, pyrite and chalcocite, covellite, bornite, malachite, azurite, hematite, goethite and limonite are secondary minerals. The amount of Cu is between 0.01 to 5.6 % and amount of Ag, Sb, Pb, Zn, As elements is low. The homogenization temperature (Th) values ranged from 165 to 300 oC. Salinities of ore-forming fluids ranged from 7 to 16 wt. % NaCl equivalents. Diorite dykes in the Robaie area have characteristics of enrichment in LREE versus HREE, enrichment of LILE and depletion in HFSE. The initial 87Sr/86Sr and 143Nd/144Nd ratios of biotite-hornblende diorite are 0.705664 and 0.512486, respectively. The εNdI value is -1.7. In the εNdI versus initial 87Sr/86Sr diagram diorite dykes of the Robaie area plot to the right part of the mantle array. The mean age of diorite dyke is 50.49±0.49 Ma. Therefore, the U-Th-Pb zircon dating indicates that diorite dyke formed in the early Eocene (Ypresian) era. Discussion Diorite dykes originated from mantle-derived magmas. The parental melt would have originated in a non-depleted mantle source. Isotopic data from diorite dykes show that subduction source with contamination to continental crust. In tectonic setting diagrams (Pearce et al., 1984) diorite dykes plot on the fields of the volcanic arc granites (VAG). In the Dy/Yb vs. Dy system (Shaw, 1970) diorite dykes of Robaie area were formed by 15-20% partial melting of spinel-phlogopite lherzolite. According to Yh/Yb vs. Ta/Yb (Pearce et al., 1984) and Ba/La vs. Th/Nd diagrams (Shaw, 1970) diorite dykes were formed from slab-drive fluid in the active continental margins. Fluid inclusions data of the Robaie area manifest that the ore-forming fluids were medium to low temperature and medium to low salinity. The pressure determined for the Robaie area was approximately < 10 MPa, which is equivalent to a depth of approximately < 1 km assuming lithostatic pressure. Fluid inclusion studies indicate that there is a positive correlation between homogenization temperature and fluid salinity, similar to the process of fluid mixing. The decrease in salinity has been the most important factor in the precipitation of copper in the area. All of evidence shows that mineralization in the Robaie area is of epithermal type deposit. Acknowledgment The financial support provided by grant no. 42842.3, date: 3 Jan 2017 is greatly appreciated. We would like to thank Mr. Ehsan Azizian of the Zamin Pouyan Fraz Assia Company for the generous support and the access to mine data.

Petrography microthermometry of fluid inclusion, quantitative grain fluorescence (QGF) and quantitative grain fluorescence on extract(QGF-E) are used to study the paleo-fluid characteristics and hydrocarbon charging history of Jurassic reservoir in Dibei gas field, Kuqa depression, Tarim Basin.The results show that the Jurassic reservoirs in Dibei gas field develop inclusions with two stages:the first stage is liquid inclusion with yellow-green color, which indicats the filling of early oil;the second stage is gas-liquid inclusion with blue-white fluorescence color and gas inclusions with non-fluorescence color, which indicats that the late gas was charged.The homogenization temperature of inclusions indicats the two stages of hydrocarbon charging. QGF and QGF-E show that the oil in the Jurassic reservoir of the Dibei gas field may be a mixture of different origins or different maturity.Combined with the sedimentary history of Dibei gas field, it is suggested that the Dibei gas field has experienced two stages of oil and gas charging.The first is the filling of oil between 18~16 Ma.Gas charging period in the second stage is 5~3 Ma.Since the Xiyu period, the tectonic movement has been strong and the gas field accumulate at low parts.

ABSTRACT: The Lower Cretaceous Yingcheng Formation in the southern Songliao Basin is the typical tight oil sandstone in China. In order to better predict the petrophysical properties of the tight sandstone reservoirs in the Lower Cretaceous Yingcheng Formation, Songliao Basin, Northeast China, the diagenesis and porosity evolution was investigated using a suite of petrographic and geochemical techniques including thin section analysis, scanning electron microscopy, mercury intrusion and fluid inclusion analysis, on a set of selected tight sandstone samples. Combined with the histories of burial evolution, organic matter thermal evolution and hydrocarbon charge, the matching relationship between reservoir porosity evolution and hydrocarbon accumulation history is analyzed. The result showed that the tight sandstone reservoirs characterized of being controlled by deposition, predominated by compaction, improved by dissolution and enhanced by cementation. The hydrocarbon accumulation period was investigated using a suite of hydrocarbon generation and expulsion history, microfluorescence determination and temperature measurement technology. According to the homogenization temperature of the inclusions and the history of burial evolution, Yingcheng Formation has mainly two phases hydrocarbon accumulation. The first phase of oil and gas is charged before the reservoir is tightened, the oil and gas generated by Shahezi source rocks enter the sand body of Yingcheng Formation, influenced by the carrying capability of sand conducting layer, oil and gas is mainly conducted by the better properties and higher connectivity sand body and enriched in the east, which belongs to the type of densification after hydrocarbon accumulation. The second phase of oil and gas charge after densification, which belongs to the type of densification before the hydrocarbon accumulation.

Abstract Beryl is usually found in granite-pegmatite systems. The addition of chromophore elements (V, Cr, Mn, Fe) into the crystalline structure favors color changes in beryl and thus generates some of the world’s expensive gems such as emerald, morganite, heliodor and aquamarine. The Massangana polyphasic batholith is a well-known cassiterite, wolframite and gems deposit in the Rondônia state. These metals and blue-gems (topaz and aquamarine) are located in feldspar-rich pegmatite granite bodies. The aquamarine crystals show color ranging from light- to medium-blue and display concentric growth zones. Electron-probe microanalyses revealed that the Fe is the main chromophore element, occupying the octahedral Al-site, while Na had an important role in the charge balance, inserted in the channel sites together with H2O. The irregular supply of Fe and Na during the nucleation and growth of aquamarine was the main cause for the color change. A fluid inclusion study indicated that the aquamarine growth under an aqueous fluid system (H2O-NaCl), with low salinity, low density and total homogenization temperature between 243º-315º C, is compatible with final temperatures in the pegmatite pocket zone.

The Junggar Basin is rich in natural gas resources, but it has hardly been explored, with the proven rate being less than 9.0%. Although the hinterland of the Junggar Basin has a favorable condition for natural gas accumulation, the complex gas sources cause great trouble in the selection of zones and belts for exploration. Based on the molecular composition and stable carbon and hydrogen isotope data of 95 natural gas samples from 72 wells in this area, combined with the characteristics of structural evolution history, burial history, hydrocarbon generation and expulsion history, and fluid inclusions, this paper clarified the geneses and sources of natural gas, identified the secondary alteration of natural gas, and restored the process of natural gas accumulation. Natural gas in the hinterland was divided into four types: Type I was oil-type gas from the Lower Permian Fengcheng Formation; Type II was coal-type gas derived from the Carboniferous source rock; Type III was the mixture of Type I and II gases, which constituted the major fraction of natural gases in the hinterland; and Type IV that referred to secondary microbial gas formed by the biodegradation of crude oil. During the Late Cretaceous, the Carboniferous and Fengcheng source rocks entered the gas generation peak and a series of natural gas reservoirs were formed. However, affected by the later tectonic movements, some gas reservoirs were damaged or adjusted, and natural gas leakage and biodegradation occurred. This study has shifted the focus of natural gas exploration in the study area from the petroleum system associated with the Middle Permian source rocks to that with the Lower Permian and Carboniferous source rocks, which is of great significance for natural gas exploration in the Junggar Basin. Further, it provides an example to identify the geneses and sources of natural gas under complex conditions based on integrated geological and geochemical assessments.

An equation of state (EOS) of CH4-N2 fluid mixtures in terms of Helmholtz free energy has been developed by using four mixing parameters, which can reproduce the pressure-volume-temperature-composition (PVTx) and vapor-liquid equilibrium (VLE) properties of CH4-N2 fluid mixtures. The average absolute deviation of all the PVTx data available up to 673.15 K and 1380 bar from this EOS is 0.38%. Combining this EOS of CH4-N2 fluid mixtures and the EOS of CH4-CO2 and CO2-N2 fluid mixtures in our previous work, an EOS of CO2-CH4-N2 fluid mixtures has been developed, which is named ZMS EOS. The ZMS EOS can calculate all thermodynamic properties of ternary CO2-CH4-N2 fluid mixtures and the average absolute deviation of the PVTx data from the ZMS EOS is 0.40% for the CO2-CH4-N2 system. The ZMS EOS can be applied to calculate excess enthalpies of CO2-CH4-N2 fluid mixtures, predict the solubility of CO2-CH4-N2 fluid mixtures in brine and water, and quantitatively estimate the impact of the impurities (CH4 and N2) on the CO2 storage capacity in the CO2 capture and storage (CCS) processes. The ZMS EOS can also be applied to calculate the isochores of CO2-CH4-N2 system in the studies of fluid inclusions. All Fortran computer codes and Origin drawing projects in this paper can be obtained freely from the corresponding author.

The Taishanmiao granitic batholith, located in the Eastern Qinling Orogen in Henan Province, China, contains numerous small (mostly tens of centimeters in maximum dimension) bodies exhibiting textures and mineralogy characteristics of simple quartz and alkali feldspar pegmatites. Analysis of melt inclusions (MI) and fluid inclusions (FI) in pegmatitic quartz, combined with Rhyolite-MELTS modeling of the crystallization of the granite, have been applied to develop a conceptual model of the physical and geochemical processes associated with the formation of the pegmatites. These results allow us to consider the formation of the Taishanmiao pegmatites within the context of varios models that have been proposed for pegmatite formation. Field observations and geochemical data indicate that the pegmatites represent the latest stage in the crystallization of the Taishanmiao granite and occupy ≤4 vol% of the syenogranite phase of the batholith. Results of Rhyolite-MELTS modeling suggest that the pegmatite-forming melts can be produced through continuous fractional crystallization of the Taishanmiao granitic magma, consistent with the designation of the pegmatites as a miarolitic class, segregation-type pegmatites rather than the more common intrusive-type of pegmatite. The mineral assemblage predicted by Rhyolite-MELTS after ~96% of the original granite-forming melt had crystallized consists of ~51 vol% alkali feldspar, 34 vol% quartz, 14 vol% plagioclase, 0.1 vol% biotite, and 1 vol% magnetite, similar to the alkali feldspar + quartz dominated mineralogy of the pegmatites. Moreover, the modeled residual melt composition following crystallization of ~96% of the original melt is similar to the composition of homogenized MI in quartz within the pegmatite. Rhyolite-MELTS predicts that the granite-forming melt remained volatile-undersaturated during crystallization of the batholith and contained ~6.3 wt% H[sub 2]O and ~500 ppm CO[sub 2] after ~96% crystallization when the pegmatites began to develop. The Rhyolite-MELTS prediction that the melt was volatile-undersaturated at the time the pegmatites began to form, but became volatile-saturated during the early stages of pegmatite formation, is consistent with the presence of some inclusion assemblages consisting of only MI, while others contain co-existing MI and FI. The relationship between halogen (F and Cl) and Na abundances in MI is also consistent with the interpretation that the very earliest stages of pegmatite formation occurred in the presence of a volatile-undersaturated melt and that the melt became volatile saturated as crystallization progressed. We propose a closed system, isochoric model for the formation of the pegmatites. Accordingly, the Taishanmiao granite crystallized isobarically at ~3.3 kbar, and the pegmatites began to form at ~734 °C and ~ 3.3 kbar, after ~96% of the original granitic melt had crystallized. During the final stages of crystallization of the granite, small pockets of the remaining residual melt became isolated within the enclosing granite and evolved as constant mass (closed), constant volume (isochoric) systems, similar to the manner in which volatile-rich melt inclusions in igneous phenocrysts evolve during post-entrapment crystallization under isochoric conditions. As a result of the negative volume change associated with crystallization, pressure in the pegmatite initially decreases as crystals form, and this leads to volatile exsolution from the melt phase. The changing PTX conditions produce a pressure-induced "liquidus deficit" that is analogous to liquidus undercooling and results in crystal growth as required to return the system to equilibrium PTX conditions. Owing to the complex closed system, isochoric PVTX evolution of the melt-crystal-volatile system, the pressure does not decrease rapidly or monotonically during pegmatite formation but, rather, gradually fluctuates such that at some stages in the evolution of the pegmatite the pressure is decreasing while at other times the pressure increases as the system cools to maintain mass and volume balance. This behavior, in turn, leads to alternating episodes of precipitation and dissolution that serve to coarsen (ripen) the crystals to produce the pegmatitic texture. The evolution of the pegmatitic melt described here is analogous to that which has been well-documented to occur in volatile-rich MI that undergo closed system, isochoric, post-entrapment crystallization. [ABSTRACT FROM AUTHOR]

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The importance of the stable isotopes in tree rings for the study of the climate variations caused by volcanic eruptions is still unclear. We studied δ18O, δD, δ13C stable isotopes of larch and cembran pine cellulose around four major eruptions with annual resolution, along with a superposed epoch analysis of 34 eruptions with 5-year resolution. Initial analysis of the tropical Tambora (1815 CE) and Samalas (1257 CE) eruptions showed a post-eruption decrease in δ18O values attributed to post-volcanic cooling and increased summer precipitation in Southern Europe, as documented by observations and climate simulations. The post-volcanic cooling was captured by the δD of speleothem fluid inclusion. The δ18O decrease was also observed in the analysis of 34 major tropical eruptions over the last 2000 years. In contrast, the eruptions of c. 750, 756, and 764 CE attributed to Icelandic volcanoes left no significant responses in the cellulose isotopes. Further analysis of all major Icelandic eruptions in the last 2000 years showed no consistent isotopic fingerprints, with the exception of lower post-volcanic δ13C values in larch. In summary, the δ18O values of cellulose can provide relevant information on climatic and hydroclimatic variations following major tropical volcanic eruptions, even when using the 5-year resolution wood samples of the Alpine Tree-Ring Isotope Record database.

The eastern Tianshan Terrane is a highly prospective zone that contains several porphyry Cu–Mo, VMS Cu–Zn, magmatic Cu–Ni, epithermal and orogenic Au deposits. However, few attention has been paid to tungsten deposits. Of these, the source and evolution of the mineralising fluids related to the skarn W deposits are poorly understood. The Heiyanshan W deposit is hosted by metamorphosed clastic and carbonate beds in the Mesoproterozoic Jianshanzi Formation deposited on a continental margin tectonic setting. The Jianshanzi Formation is intruded by biotite monzogranite that yield weighted 206Pb/238U age of 326.9 ± 1.6 Ma, which suggest that the Heiyanshan W deposit was formed in the Carboniferous. The mineralisation is hosted by a prograde hydrothermal altered zone represented by a garnet (–pyroxene) skarn, and retrograde skarn characterised by fine-grained scheelite. The paragenesis of the Heiyanshan mineralisation can be subdivided into prograde skarn stage, retrograde skarn stage, quartz-sulphide stage and quartz-calcite vein stage. The types of fluid inclusions recognised in the various minerals in the deposits are liquid-rich aqueous, vapour-rich aqueous, and daughter mineral-bearing. The homogenisation temperatures of fluid inclusions from the Heiyanshan deposit decrease from 290 ± 28°C in garnet, through 232 ± 31°C in scheelite, to 232 ± 36°C in quartz and 158 ± 15°C in non-mineralised calcite, which is typical of W-bearing skarn deposits worldwide. The δ18Owater values from the Heiyanshan deposit range from +4.7 to +6.6‰ in garnet, +1.3 to +1.9‰ in quartz and −6.1 to −4.4‰ in calcite. We have measured δD in fluid inclusions from different minerals, although these bulk analyses are just a mixture of the different FIA’s present in the sample. The δD values of fluid inclusions in garnet, quartz, and calcite are from −121 to −71‰, −84 to −75‰ and −101 to −82‰, respectively, also indicative of deep-sourced magmatic fluids mixed with meteoric water. The decrease in the homogenisation temperatures for the fluid inclusions at the Heiyanshan deposit is accompanied by a drop in salinity indicating that tungsten-bearing minerals precipitated during fluid mixing between magmatic fluids and meteoric water. We conclude that eastern Tianshan Terrane contains two pulse of tungsten metallogenic events of Late Carboniferous and Early Triassic.

Sichuan Basin is the only successful basin for shale gas exploration in China. In addition to the main shale in the Lower Silurian Longmaxi formation, the lower Cambrian Qiongzhusi shale is an important potential formation. However, it was once considered that shale gas is difficult to enrich because of its poor sealing conditions and hydrocarbon migration to adjacent reservoirs. With the increasing research on hydrocarbon generation and reservoir in shale of Qiongzhusi Formation in recent years, it has become an important exploration target in Sichuan Basin. The enrichment of oil and gas is closely related to fluid activities. Limited by the degree of exploration, there is little analysis of fluid activities in Qiongzhusi Formation, and there is little analysis of shale gas enrichment potential from the perspective of fluid. The hydrocarbon generated from Qiongzhusi shale in the rift could migrate laterally to the uplift area and form a reservoir in Dengying Formation. The fluid activities from source rock to reservoir are basically the same. Therefore, this paper reconstructed the history of hydrocarbon activities in Dengying reservoirs based on fluid inclusion analysis. Then the fluid activity process in Qiongzhusi shale was studied, and its enrichment conditions of shale gas was discussed. The results show that the hydrocarbon activities of Dengying Formation can be divided into three stages: 1) oil charging stage, 2) oil cracking gas generation stage and 3) gas reservoir adjustment stage. The first stage is under normal pressure, and the second and third stages developed overpressure with pressure coefficients of 1.3 and 1.2, respectively. High pressure coefficient is an important indicator of shale gas enrichment. Because the source rock of Qiongzhusi Formation has always been the main source rock of Dengying Formation, it can supply hydrocarbon to Dengying Formation only with overpressure in gas generation stage. Therefore, overpressure in the last two stages of gas generation indeed existed. As long as the sealing condition of shale itself is not particularly poor, shale gas “sweet points” would be formed. Therefore, the thick shale in Deyang-Anyue rift is the focus of shale gas exploration in Qiongzhusi Formation.

The Okinawa Trough is an extensive back-arc basin that was formed by the subduction of the Philippine Sea plate beneath the Eurasian continent. Instances of Zn–Pb–(Cu) mineralization, which are typically associated with volcanism, are commonly found in many of the hydrothermal fields throughout this trough. We analysed the fluid inclusions and helium isotopic compositions of samples collected from the sulphide–sulphate chimneys/mounds in the Iheya North Knoll hydrothermal field in the Middle Okinawa Trough. For fluid inclusions in sphalerite and anglesite, we found that the homogenization temperatures ranged from 288°C to 345°C and 242°C to 370°C, while the salinity values ranged from 5.45 to 10.55 wt.% NaCl equiv. and 6.45 to 8.55 wt.% NaCl equiv., respectively. Microthermometry results from these inclusions yielded temperatures of 330°C–350°C; at these temperatures, seawater may have been boiling during the ore formation process. These data, in addition to measurement of high hydrothermal fluid 3He/4He ratios (6.5 to 7.8 Ra), suggest that the fluid is mainly derived from the back-arc basin basalts (BABBs), and have been mixed with a small amount of seawater. Moreover, the 3He enrichment found in this hydrothermal system indicates that these fluids may be sourced from deeper basaltic magma, rather than strongly degassed rhyolitic magma. Based on these anglesite-hosted fluid inclusions and the results of IODP Expedition 331 in this hydrothermal field, we infer that multiple hydrothermal fluid reservoirs exist beneath the seafloor in this region; the accumulation and migration of various solutions in these reservoirs promote mineralization, and extensive alteration of the host rocks. Mantle-derived He enters the hydrothermal fluid system by basaltic magma degassing. After experiencing fluid mixing, phase separation, and cooling, Pb–Zn–(Cu) minerals ultimately precipitate out of this hydrothermal fluid. [ABSTRACT FROM AUTHOR]

The Jebel Lassel (JL) and Bou Izem (BIZ) Pb–Zn–F mineralizations are widely found in the Djamila nappe which is the dominant structural unit in the Kherrata area (northern Algeria). They are hosted respectively in Upper Cretaceous limestone and marly limestone and in dolomite from a Triassic complex at the contact of the thrust sheets. They occur in tension veins of different fillings and directions which can be divided into several types: (i) galena-calcite veins, (ii) sphalerite-calcite veins, and (iii) fluorite-calcite veins. The mineralizations consist mainly of galena or sphalerite, fluorite, and pyrite. Supergene oxidation minerals include cerusite, smithsonite, and iron oxides. Calcite, dolomite, and to a lesser extent quartz are the main gangue minerals. Fluid inclusions (FI) from Bou Izem fluorite samples occur in three phases at room temperature (L + V + halite) and homogenize by the dissolution of the halite crystal after the vapor bubble has disappeared. They are characterized by high salinities (28–39% wt% NaCl equiv.) and high homogenization temperatures (Th) (222–299 °C). Single-phase fluid inclusions are very abundant in quartz crystals from the Bou Izem borehole samples. These inclusions contain a CO2 and CH4 mixture and are nearly pure methane with less than 10% CO2. At the Jebel Lassel anticline, FIs in fluorite and sphalerite exhibit low ice-melting temperatures (– 11 and – 37 °C) and homogenization temperatures in the liquid phase of 103–174 °C. Primary FIs in calcite studied in late crystals associated with sulfides and fluorite have Th of 141–196 °C, with the final ice-melting temperatures (Tm(ice)), ranging from − 37 to − 8 °C, corresponding to salinity values ranging between 14 and more than 23.2 wt% NaCl equiv. δ13CV-PDB values of the calcite gangue, which vary between − 1 and + 2‰, indicate an inorganic carbon origin and are consistent with a marine origin of the host rocks and heritage. Most δ18OV-SMOW values of calcites are between + 16 and + 25‰ and indicate that the oxygen isotopic compositions of the fluids varied between + 5 and + 16 ‰. These values are typical of deep brines in sedimentary basins. δ34SV-CDT values vary from 9.5 to 9.8 (galena) and from 12.7 to 14.5‰ (sphalerite), and the high temperature of the fluid exclude all possibilities of bacterial sulfate reduction and indicate that the source of the sulfur is the thermochemical reduction of sulfate from Triassic evaporites (δ34S = + 15‰). The fluorite samples from JL and BIZ reveal that all patterns fit into two different types without (Eu) and (Ce) anomalies. Combined, geological, mineralogical, isotopic, and geochemical data of vein mineralization at Jebel Lassel and Bou Izem confirm the epigenetic character of the mineralization and enable us to classify them as Mississippi Valley-type deposits. [ABSTRACT FROM AUTHOR]

The Dongzigou Pb-Zn deposit is located in the south-eastern margin of Yangtze block, Midwest China. Ore bodies are hosted in Sinian carbonate rocks. The main metallic minerals are sphalerite and galena, while the non-metallic minerals are dolomite, barite, and quartz. Three stages of hydrothermal mineralization are an early quartz-pyrite stage (stage I), a middle sphalerite-galena stage (stage II), and a late sphalerite-barite stage (stage III). The main types of fluid inclusions for the Dongzigou deposit are liquid-rich inclusions (L0-type). Laser Raman analysis indicates that the fluid inclusions within the hosted minerals are dominated by H2O. Given the fluid inclusion data, the homogenization temperatures range from 220.0–300.0 °C (stage I), 126.7–243.9 °C (stage II), and 117.0–201.0 °C (stage III), respectively. Fluid salinities range from 3.4–11.8 wt% NaCl eq. (stage I), 3.6–10.7 wt% NaCl eq. (stage II), and 2.0–6.5 wt% NaCl eq. (stage III), respectively. Indicating that the ore-forming fluid of the Dongzigou deposit tends to decrease in salinity and homogenization temperature during the fluid evolution process. The δD (−63.4% to −49.8%) and δ18OH2O (0.6 to 13.7%) data from stage I to stage III which indicate that the ore-forming fluids derived from formation water, and in the late stage of hydrothermal mineralization mixed with meteoric water. The LA-ICPMS results show that sphalerite enriched Cd (1272–3437 ppm), Ge (201–717 ppm), and Ga (0.1–130 ppm), but poor in In (0.01–0.1 ppm). Through comparative studies with the trace elements of sphalerite from different types of Pb-Zn deposits, it is found that the trace element characteristics of the Dongzigou deposit are most similar to the MVT deposits. Overall, the Dongzigou Pb-Zn deposit is an atypical MVT deposit, and the salinity of fluid inclusions is lower than that of typical MVT deposits. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Chinese Altay in Northwest China and adjacent regions in the Russian and Mongolian Altay form a tungsten province within the Central Asian Orogenic Belt. Unlike the Russian and Mongolian Altay, almost no tungsten deposits in the Chinese Altay have been reported. The Basitielieke deposit located in the Altay orogenic belt in Xinjiang is a newly discovered polymetallic tungsten deposit hosted in the skarn in the exocontact zone of a granite pluton. Mineralization can be divided into the skarn period and supergene oxidization period, the skarn period can be further divided into a prograde skarn stage (I), a retrograde skarn stage (II), and a quartz–sulphide stage (III). Scheelite mineralization mainly occurred in stage II, and Cu–Zn–Au formed in stage III. The ore‐forming fluid can be divided into a H2O–NaCl systems, including stage I (211 to 480°C and 2.24 to 14.04 wt% NaCl equiv) and stage II (178 to 336°C and 4.96 to 9.47 wt% NaCl equiv), and a H2O–CO2 (±CH4/N2)–NaCl system in stage III (130 to 434°C and 1.40 to 9.60 wt% NaCl equiv). Hydrogen, oxygen, and sulphur isotope compositions indicate that magmatic water participated in the hydrothermal mineralization system in stage I, and meteoric water increased with the process of mineralization. Sulphur was derived from deep‐seated magmas. The Basitielieke deposit is a reduced skarn polymetallic tungsten deposit. The deposit formed by hydrothermal fluid from the granite interacting with strata during the Early Permian, the fluid–rock interaction and fluid mixing (magmatic water and meteoric water) was the main precipitation mechanism of the Basitielieke polymetallic tungsten deposit. [ABSTRACT FROM AUTHOR]

This paper describes the results of surficial geological and alteration mapping combined with several laboratory analyses, including petrography, ore microscopy, ore geochemistry, and fluid inclusion studies, aimed at establishing the nature of mineralization and alteration in the Cibeber area, West Java, Indonesia, and developing a genetic model. The area forms part of the Bayah Dome Complex, which hosts several gold-silver deposits. It is underlain by andesitic lava, tuff breccia, and subordinate sandstone. Its structural framework consists of joints, normal faults, NE-SW dextral strike-slip faults, and NW-SE strike-slip faults. Hydrothermal alteration can be divided into four types, viz. silicification, clay-silica, argillic, and propylitic. Mineralization is mostly hosted in quartz veins showing a variety of textures, including massive, colloform-crustiform, breccia, lattice bladed, comb, and saccharoidal. Ore minerals consist of native gold and silver, pyrite, chalcopyrite, sphalerite, galena, tennantite-tetrahedrite, covellite, malachite, hematite, and goethite, while the gangue minerals quartz, illite, epidote, and calcite. Four stages of mineralization/veining are recognized: early, middle (the main ore forming stage), late, and supergene. The highest obtained metal grades are 8.17 ppm Au, 113.6 ppm Ag, 1.23% Cu, 1.28% Pb, and 1.2% Zn. Fluid inclusions from mineralized veins yielded temperatures of 222 - 280°C and salinities of 0.36 - 1.31 wt.% NaCl eq. The hydrothermal fluids are interpreted to have been largely of meteoric origin with the mineralization having formed at a depth of about 258 - 270 m below paleosurface. Both low-sulphidation and intermediate-sulphidation styles of mineralization are present. [ABSTRACT FROM AUTHOR]

There is increasing acceptance of the presence of variable magmatic contributions to the mineralizing fluids in the formation of volcanogenic massive sulfide (VMS) deposits. The world-class Windy Craggy Cu-Co-Au deposit (>300 MT @ 2.12 wt% Cu) in northwestern British Columbia is of interest because, unlike most VMS deposits, fluid inclusions in quartz from within the deposit range from relatively low to intermediate salinity (most 6–16 wt% equivalent). In this study we used an excimer (193 nm) laser ablation system interfaced to a quadrupole inductively coupled plasma mass spectrometer to quantify key metals and metalloids that are considered by many to be indicative of magmatic contributions to hydrothermal ore deposits. Although LA-ICP-MS signals from these low-salinity inclusions are highly transient, we were able to quantify Na, Mg, K, Ca, Mn, Fe, Co, Cu, Zn, Sr, Sn, Ba, Ce, Pb and Bi consistently – of the 34 elements that were monitored. Furthermore, Cl, Sb, Cd, Mo, Rb, Br and As were also measured in a significant number of inclusions. Comparison of the fluid inclusion chemistry with unaltered and altered mafic volcanic and sedimentary rocks and mineralized samples from the deposit indicate that enrichment in the main ore metals (Cu, Zn, Fe, Pb) in the inclusions reflects that of the altered rocks and sulfides. Metals and metalloids that may indicate a magmatic contribution typically show much greater enrichments in the fluid inclusions over the host rocks at the same Cu concentration; in particular Bi, Sn and Sb are significantly elevated when compared to the host rock samples. These data are consistent with the ore-forming fluids at Windy Craggy having a strong magmatic contribution. Supplementary material: fluid inclusion data for temperature of homogenization and salinity, and full analytical results for laser ablation ICP-MS analyses of individual inclusions for the two analytical sessions are available at https://doi.org/10.6084/m9.figshare.c.5443094 [ABSTRACT FROM AUTHOR]

The Huangshui'an deposit located in East Qinling (China) is an unusual case of a Si-rich carbonatite hosting economic Mo and minor Pb and REE mineralization. The role of mantle-sourced carbonatite melts and fluids in the formation of the Mo mineralization remains poorly understood. Our integrated study based on field geology, petrography, microthermometry, and LA-ICP-MS analysis of single fluid inclusions, and noble gas isotopes of pyrite permits to reconstruct the source characteristics, the magmatic-hydrothermal evolution of the carbonatitic fluids, and their controls on Mo mineralization. Fluid inclusions hosted in calcite in the carbonatite dikes have the highest concentrations of Mo (9.9–62 ppm), Ce (820–9700 ppm), Pb (1800–19500 ppm), and Zn (570–5800 ppm) and represent the least modified hydrothermal fluid derived from the carbonatite melt. Fluid inclusions hosted in calcite (Cal) and quartz (Qz2 and Qz3) of the stage I carbonatite dikes have different metal concentrations, suggesting that they formed from two distinct end member fluids. The FIA in calcite represent fluid A evolved from carbonatite melt with relatively high-ore metal concentrations, and those in quartz characterize fluid B having a crustal signature due to metasomatic reactions with the wall rocks. The FIA in quartz (Qz1) within the altered wall rock have overlapping elemental concentrations with those of massive quartz (Qz2) and vuggy quartz (Qz3) in carbonatite. This suggests that the volumetrically significant quartz in the Huangshui'an carbonatite has been formed by the introduction of Si by fluid B. The positive correlations between Rb, B, Al, Cl, and Sr in stage II fluid inclusions in late fluorite + quartz + calcite veins indicate that this late mineralization formed from the mixing of primary hydrothermal fluid B with meteoric water. The He–Ar isotope data, in combination with available C–O–Sr–Nd–Pb isotope data, constrain the carbonatite source as an enriched mantle source modified by contributions from crustal material which was probably the fertile lower crust in the region. This distinct source facilitated the enrichment in Mo, REE, and Pb in the primary carbonatite magma. The carbonatite magmatism and Mo mineralization at 209.5–207 Ma occurred in the regional-scale extensional setting at the postcollision stage of the Qinling Orogenic Belt. [ABSTRACT FROM AUTHOR]

We present a new experimental dataset on the impact of the heavy halogens chlorine, bromine and iodine on the Raman water bands concerning pressure and their concentration at room temperature. These experiments were conducted at ambient temperature, with variations in halogen concentration and pressure ranging from 0 to 1.4 GPa. The strength of the Raman water band shift change increases with the ionic size from chlorine, over bromine, to iodine. Our experiments further demonstrate that increased pressure diminishes the impact of the halogen shift change to a varying extent for each of the three halogens. This finding can have significant implications for the salinity calculation of fluid inclusions in minerals such as quartz or olivine. Particularly in the low salinity range, the concentration can be markedly underestimated if the pressure effect is neglected. For experiments in diamond anvil cells involving halogens dissolved in water, the change in Raman water band shifts can serve either as a new tool to monitor pressure, or to monitor the salinity. [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]

The Sichuan Basin has experienced multi periods of tectonic uplift event, accompanied with multiple hydrocarbon accumulation and phase transitions processes in the deep and ultra-deep reservoirs. The formation of paleo-oil reservoir plays an important role in the distribution of present-day gas fields, yet many records of early oil reservoirs have been destroyed. A series of methods including, petrography, cathodoluminescence, fluid inclusion, in-situ U–Pb geochronology, and basin modeling, were used to determine the multistage oil charge process in the Ediacaran Dengying Formation of the Weiyuan area, SW Sichuan Basin. The lace-like dolomite lamination and three stages of dolomite cement were petrographically, and geochronologically distinguished in the Dengying Formation, dated at c. 542 Ma, 486–482 Ma, 410 Ma, and 270 Ma, respectively. Three stages of bitumen in the Dengying reservoir indicated three episodes of oil charge. The first and second oil-charging events occurred at 500–486 Ma and 410–400 Ma, by combining the modeled timing of oil generation with mineral ages of the two generations before and after the solid bitumen. The modification of the Weiyuan paleo-oil pool occurred during the Caledonian tectonic uplift, after the second oil-charging event. The timing of the third oil charge was at 270–230 Ma, according to the Th value of aqueous inclusions coeval with secondary bitumen inclusions in the stage 3 dolomite cement (CD-3), close to the timing of main oil generation for the Lower Cambrian source rocks. The first oil charge may be a contribution from the Doushantuo source rock, and the Lower Cambrian source rocks provide the major contribution for the third oil charge. This research reveals the timing of multistage oil charging events in the southwest Sichuan basin, and provides a further method for determining the timing of oil charge in multi-cyclonic composite basins. • The integrated petrography, fluid inclusion, and dolomite U–Pb geochronology analysis on the carbonate reservoir helps to reveal the diagenetic sequences. • Agreement between the timing of bitumen inclusion trapping and modeled oil generation. • Diagenetic sequence and absolute age of minerals combine to constrain the timing of the early oil charge represented by reservoir bitumen. • Three sets of source rocks in the Ediacaran - Lower Cambrian provided contributions to the three-stage oil charge processes. [ABSTRACT FROM AUTHOR]

The Penglai area is an emerging giant gas field in the Sichuan Basin supporting the carbon neutrality goal. To accelerate the exploration, this study combines petrographic observations using optical and cold cathodoluminescence microscopy, fluid inclusion microthermometry, Raman spectroscopy, 1D basin modeling and fluid inclusion PVTX modeling techniques to reveal the paleo-fluid P-T evolution in the second member of the Dengying Formation (Ediacaran age). The results firstly showed a diagenetic sequence which includes three phases of dolomite (1–3), bitumen, quartz (core and overgrowth) and fluorite. Then, ten paleo-fluid episodes were identified based on microthermometric histograms of different mineral phases. Finally, by integrating the Raman results, the hydrostatic and lithostatic gradients calculated by the constructed 1D basin model, and the existing equation of states, the homogenization pressure of fluid inclusions from each fluid episode was determined. By assuming the system was saturated by CH 4 as suggested by Raman results, the homogenization pressure equals to the trapping pressure. The P-T trajectory indicates that the second member of the Dengying Formation experienced two sever pressure accumulation stages. One is between fluid episode #3 and #4 recorded by dolomite 3, due to oil generation, and the other is from fluid episode #5 in dolomite 3 to episode #7 in quartz overgrowth to episode #8 in fluorite due to oil cracking to gas. Also, two pressure releasing periods were recorded by fluid episode #5 in dolomite 3 and #9 and #10 in fluorite, caused by both basin uplifting and fluid pressure reaching the lithostatic pressure. This study provides insights into fluid pressure evolution in deeply buried carbonate reservoirs. The understandings can support further geoenergy utilization and reduce exploration risks. • Diagenetic evolution and fluid evolution of carbonate buried over 6000m. • Rigorous fluid inclusion data allows to quantify the evolution of P-T conditions in a deep carbonate reservoir with time. • Overpressure evolution results demonstrate that the area with pale-fluid over pressure favored the preservation of pore spaces in the deep carbonate reservoir. [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] • Ershiyizhan deposit formed in an extensional setting following closure of the Mongol–Okhotsk Ocean in the early Cretaceous. • Cu and Au originated from fluid boiling and mixing. • Ore materials originated from both quartz-monzonite porphyry and surrounding rocks. • Ore-forming fluids gradually evolved from magmatic water to meteoric water. The Ershiyizhan Cu–Au deposit, located in the eastern part of the upper Heilongjiang metallogenic belt, north of the Great Xing'an Range, is composed of orebodies from the Mesozoic magmatic rocks and the Ershierzhan group. There are three metallogenic stages of this deposit, (1) Quartz-K-feldspar-polymetallic sulfide stage (stage Ⅰ), (2) quartz-polymetallic sulfide stage (stage II), and (3) quartz-calcite ± pyrite stage (stage Ⅲ). Three types of fluid inclusions (FIs) were discovered in the vein mineral assemblages, liquid-rich two-phase aqueous FIs (L-type), vapor-rich aqueous FIs (V-type), and multi-phase FIs (S-type) with daughter minerals, including S1-type inclusions homogenized through vapor disappearance and S2-type inclusions homogenized by halite dissolution. Quartz of stage I and stage II contains all of these FIs. In contrast, the L-type fluid inclusions of stage III veins are the only ones present in the calcite. The homogenization temperatures and salinities obtained from FIs in stages I, II, and III range from 330 to 563 °C, 223 to 423 °C, and 108 to 225 °C, and 0.88 to 66.18 wt%, 2.41 to 48.59 wt%, and 0.18 to 3.23 wt% NaCl equiv., respectively. δ18O and δD values obtained from stable isotope analyses of K-feldspar and quartz samples collected from stages I, II, and III range from −2.31 to 7.89 and −133.2 to −98.2, respectively. Microthermometry and H-O isotope data from FIs suggest that the ore-forming fluids of the deposit had a magmatic origin, characterized by high temperatures, low–high salinities, an H 2 O-NaCl fluid system and this fluid system evolved to a low temperature, low salinities fluid through the gradual combination of meteoric water from stages II to III. Trapping pressures estimated from boiling L-type, V-type, and S1-type fluid inclusions in stage Ⅰ were 100–500 bars, corresponding to a mineralization depth of 1.0 to 5.0 km, with fluid boiling and mixing likely being responsible for the precipitation of sulfides and gold. K-feldspar from an auriferous vein of stage I yielded an 40Ar/39Ar isotopic plateau age of 131.21 ± 0.52 Ma, suggesting that the mineralization of the deposit is closely associated with the Early Cretaceous quartz monzonite porphyry. The analysis of the S isotope of metal sulfides in this deposit demonstrate that the sulfur reservoir is primarily derived from a hybrid magma source consisting of both mantle-derived and crustal-derived materials. Lead radioactive isotopic analysis for metal sulfides and various wall rocks also implies the lead source is a mixed source of upper crust and mantle. Thus, S-Pb isotope studies indicate that a crust-mantle mixed source for the mineralization of the deposit, and ore-forming material may originate from both quartz monzonite porphyry and various surrounding rocks including Late Triassic-Early Jurassic monzogranite, granite, quartz syenite, and the Ershierzhan Formation. Considering the geology, geochronology, FI, and H-O-S-Pb isotopic characteristics, the Ershiyizhan Cu–Au deposit is classified as a porphyry deposit formed in an extensional environment due to the delamination of the thickened lower crust following the Mongolian-Okhotsk Ocean closure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluids from all paragenetic stages show magmatic signatures. • Discrete pulses of magmatic fluids for both prograde and retrograde skarn stages. • Fluid cooling serves as the principal factor for Cu precipitation. • Fluid-rock reaction may exert a secondary influence on sulfide precipitation. Skarn deposits are significant sources of copper, yet there are different understandings on their fluid evolution and precipitation mechanism due to lack of direct constraints on fluid compositions of mineralization process. Here, we present a detailed reconstruction of fluid evolution history from the pre-ore prograde stage through the syn -ore retrograde stage to the post-ore stage of the Chuankeng deposit in the North Wuyi area, South China, based on fluid inclusion microthermometry and LA-ICP-MS analysis of typical minerals from three stages. The pre-ore fluids trapped in pyroxene have higher homogenization temperatures (450–550 ℃), higher salinities (31.9–51.5 wt% NaCl equiv), but lower concentrations of Cu (∼556 ppm) than syn -ore fluids (338–465 ℃, 31.3–38.9 wt% NaCl equiv, ∼3247 ppm Cu). The post-ore fluids show lower temperatures (139-163℃), salinities (1.1–6.5 wt% NaCl equiv), and low concentrations of Cu (<387 ppm). Fluids of all paragenetic stages have high K/Na and Rb/Na ratios, exhibiting signatures of magmatic hydrothermal fluids. Mixing of the magmatic fluids with meteoric waters of lower temperature and salinity occurred at the final post-ore stage, thus it is not related to Cu mineralization. As the temperature descends from 445 ℃ to 340 ℃, the Cu/(Na + K) ratios of syn -ore fluids diminish exponentially, manifesting fluid cooling within a certain temperature may be an important factor controlling Cu mineralization. Concomitantly, a moderate negative correlation between the Ca/(Na + K) ratios and Cu/(Na + K) ratios of syn -ore fluids suggests that fluid-rock interaction do have some impact on copper contents. Additionally, the Cu/(Na + K) ratios of syn -ore fluids in quartz are an order of magnitude higher than those of pre-ore fluids, and it is proposed that during the initial retrograde stage—the onset of mineralization—the magma chamber released fluid pulse with higher copper contents. Based on these findings, the fluids of pre-ore prograde stage and syn -ore retrograde stage are distinct magmatic fluid pulses, and copper-rich fluids, thermal cooling within a specific temperature range and fluid-rock reaction are suggested to be key factors controlling metal enrichment in skarn copper systems. [ABSTRACT FROM AUTHOR]

Carbonate clumped-isotope (Δ 47) paleothermometry offers a novel means of reconstructing the paleoburial temperature of carbonate rocks. However, the application of this thermometer is challenging when applied to thermal history reconstruction in deeply buried reservoirs, due to potential modifications to the Δ 47 value of carbonate mineral by C–O bond solid-state reordering. Although four reordering models have been proposed based on high-temperature laboratory experiments, the operation of Δ 47 reordering under geological conditions is still not fully understood. The Δ 47 and homogenization temperature (T h) of primary fluid inclusions trapped within the dolomite cements from the Central Sichuan Basin, China were measured. The Δ 47 evolution of the dolomite samples were predicted with the four published reordering models under the constraints of independent thermal history reconstruction and T h -derived initial Δ 47 values. The results of this study demonstrate that T h of fluid inclusion can be a valid indication of precipitation temperature of dolomite cements even when the samples experience peak burial temperature (T max) up to ∼200–240 °C. It also indicate current reordering models have overall equivalent ability for Δ 47 prediction although there are discernible differences between sample types across different models. Both T max and model-determined threshold behavior of Δ 47 reordering control the reordering pathway for model prediction, and the threshold behaviors of our dolomite samples were explored under geological conditions. In this framework, the threshold temperature (∼190 °C) for detectable dolomite reordering may be substantially higher than previous model predictions (120–150 °C). Moreover, the temperature at which the Δ 47 temperature fully equilibrates with the ambient temperature during sequential burial could exceed 240–250 °C. These threshold behaviors of bond reordering in dolomite under geological conditions are different from previous model calculations. Therefore, T max and threshold temperatures of Δ 47 reordering for different models should be considered when reconstructing thermal history based clumped-isotope solid-state reordering modeling. Our findings have significant implications for understanding the dolomite clumped-isotope reordering process and reconstructing the thermal history of deeply buried carbonate rocks. • Homogenization temperature of fluid inclusion is used to indicate initial Δ 47 value. • Independently thermal history is used to constrain bond reordering kinetic modeling. • Reordering models are evaluated under geological conditions. • New threshold temperatures for Δ 47 reordering in dolomite are proposed. [ABSTRACT FROM AUTHOR]

The Tianbaoshan deposit, located in the Sichuan–Yunnan–Guizhou (SYG) metallogenetic belt, is one of famous Pb Zn deposits of Southwest China, with an established reserve of 2.6 Mt. Pb and Zn. According to the detailed field geological survey and microscopic petrography observation, three distinct ore fluid evolution stages can be divided. In this contribution, sphalerite and associated quartz from above diverse stages were carefully chosen for systematic fluid inclusion (FI) petrography, microthermometry, individual FI LA-ICP-MS analysis, Raman microspectroscopy, and in situ trace element investigation of sphalerite. The sphalerite only defines a two-phase aqueous FI type, while the FIs hosted in quartz exhibit diverse types, including two-phase aqueous FIs, vapor-rich FIs, and pure aqueous fluid inclusions. Our microthermometry results indicate that the homogenization temperature (Th) and salinity of FIs in sphalerite from the stage 1 are 109.6‐182.2 °C and 12.51–21.61 wt% NaCl equiv., respectively. The Th of the sphalerite-hosted fluid inclusions in stage 2 ranges from 97 to 158.3 °C, with a salinity range of 14.46–19.76 wt% NaCl equiv. The FIs trapped in sphalerite exhibited medium-high salinity and low Th, and Raman spectrum analysis shows that vapor composition of the FI is mainly H 2 O, reflecting the typical characteristics of basin brine. Measurements on quartz-hosted FIs yield homogenization temperatures from 134.3 to 233.1 °C, with a salinity from 4.49 to 12.62 wt% NaCl equiv. The gas phase composition of these inclusions is complex and consists of several components, such as CH 4 , N 2 , CO 2 , and H 2 O. The results indicate that the FIs present in quartz are dissimilar from those in sphalerite, and the sphalerite mineralization fluid has typical characteristics of basin brine and represents the ore-forming fluid. The significantly high Na and Ca of the mineralizing fluid is revealed, suggesting that the mineralizing fluid may be of the Na Ca system. Combined with Ca/K, K/Na and Rb/Na ratio, typical basinal brines origin was constrained by fluid composition analysis. The gradual enrichment of Ca, Mg, and Sr in the mineralizing fluid emphasizes the positive effect of fluid-rock reactions on the precipitation of Zn. The trace element in sphalerite of the Tianbaoshan deposit is distinct from SEDEX-, skarn-, and volcanogenic massive sulfide (VMS)-type deposits and notably similar to MVT deposits. Combining with fluid inclusion and sphalerite trace elements feature, we define the Tianbaoshan deposit as a typical MVT Pb Zn deposit. • Homogenization and freezing temperatures are similar to those of typical MVT brines. • Water-rock reactions play a positive role on the precipitation of Zn. • The ratios of K, Na, Cl, Br in ore-forming fluid also show the typical characteristics of basin brine. • The Tianbaoshan deposit is a typical MVT Pb Zn deposit. [ABSTRACT FROM AUTHOR]

The Khan-Khatun Zn Pb deposit is located in the southeast margin of the Tabas Block of the Central Iranian Microcontinent. The stratabound Zn Pb mineralization is of epigenetic origin and hosted by the Late Cretaceous limestones. The ore deposition occurred in structural open spaces and much less as a disseminated replacement in carbonate rocks. The deposit consists of sulfide and non-sulfide base metal ore types. Sulfide ores include sphalerite, galena, and minor amounts of pyrite and chalcopyrite. Three paragenetic stages are recognized: pre-, hydrothermal, and supergene mineralization. Fine-grained pyrite and chalcopyrite (0.02 to 0.15 mm) precipitated during the early stages of hydrothermal mineralization. Galena formed with or sometimes after sphalerite. The δ34S values of sphalerite and galena range from +10.4 ‰ to +13.7 ‰ and + 10.2 ‰ to +14.1 ‰, respectively, and are consistent with thermochemical sulfate reduction (TSR) of the Jurassic evaporites. Willemite is an abundant non-sulfide mineral characterized by red-brown to white colors. The red-brown willemite formed during the late stages of the hydrothermal mineralization. The δ18O values of red-brown and white-colored willemite vary from +14.3 to +16.1 ‰ and − 9.62 to −8.1 ‰, respectively. Differences in δ18O values between red-brown willemite and white-colored willemite are probably the result of hydrothermal and supergene processes. Homogenization temperatures of primary fluid inclusions in calcite coexisting with sulfide ores and red-brown willemite range from 110 to 210 °C and 112 to 177 °C, respectively. The salinities of aqueous fluid inclusions of calcite and red-brown willemite vary from 11.1 to 21.26 wt% NaCl equiv. and 10.61 to 16.15 wt% NaCl equiv., respectively. Microthermometric measurements, isotopic analyses, geochemical, mineralogical, and textural evidence indicate that the mineralization process at the Khan-Khatun Zn Pb deposit is consistent with Mississippi Valley-type (MVT) deposits. [ABSTRACT FROM AUTHOR]

Abstract We re-evaluate the Raman spectroscopic quantification of the molar ratio and pressure for CH4–CO2 mixtures. Firstly, the Raman quantification factors of CH4 and CO2 increase with rising pressure at room temperature, indicating that Raman quantification of CH4/CO2 molar ratio can be applied to those fluid inclusions (FIs) with high internal pressure (i.e., > 15 MPa). Secondly, the v 1(CH4) peak position shifts to lower wavenumber with increasing pressure at constant temperature, confirming that the v 1(CH4) peak position can be used to calculate the fluid pressure. However, this method should be carefully calibrated before applying to FI analyses because large discrepancies exist among the reported v 1(CH4)-P curves, especially in the high-pressure range. These calibrations are applied to CH4-rich FIs in quartz veins of the Silurian Longmaxi black shales in southern Sichuan Basin. The vapor phases of these FIs are mainly composed of CH4 and minor CO2, with CO2 molar fractions from 4.4% to 7.4%. The pressure of single-phase gas FI ranges from 103.65 to 128.35 MPa at room temperature, which is higher than previously reported. Thermodynamic calculations supported the presence of extremely high-pressure CH4-saturated fluid (218.03–256.82 MPa at 200 °C), which may be responsible for the expulsion of CH4 to adjacent reservoirs.

Introduction More than 300 sediment-hosted Zn–Pb deposits and occurrences have been recognized in Iran (Rajabi et al., 2013). Most of these deposits are concentrated in the Central Alborz, Tabas-Posht-e-Badam, Malayer-Esfahan and Yazd-Anarak metallogenic belts (Rajabi et al., 2012). Several Pb–Zn deposits and occurrences such as Tarz, Tappeh-Sorkh, Deh-Askar, Abheydar, Gicherkuh, Ahmadabad (BonehAnar), Gujer, Karvangah, Tajkuh, Magasou and Gavar (Javar) occur in Kuhbanan-Bahabad area in the Central Iran zone. The Tarz deposit is situated about 15 km east of the Kuhbanan city in the Tabas-Posht e Badam metallogenic belt. The aims of this study are to investigate ore and host rock petrography, geochemical investigations of ore samples, fluid inclusions in coexisting transparent gangue minerals (calcite) and Microthermometric analysis of fluid inclusions in the various paragenetic stages present in the Tarz deposit. These studies have led to a genetic model of the Tarz deposit. Materials and methods Ore samples were collected from both mining tunnels and surface outcrops of mineralization. Detailed petrographic studies were conducted on hand specimens, thin and polish sections using reflected and transmitted light microscope. Representative samples were analyzed by using inductively coupled plasma emission spectrometry (ICP-ES) for major and minor elements at the Zar Azma Company in Tehran, following acid digestion. Calcite samples of different mineralization stages were collected from all major orebodies and were prepared as doubly polished sections. Microthermometric measurements were carried out on a Linkam THMSG600 Heating–Freezing stage in Fluid Inclusion, with a German Zeiss microscope. Results The primary Zn–Pb sulfide mineralization in the Tarz mine occurs as vein-type and open-space filling, consisting mainly of sphalerite and galena with minor amounts of pyrite and trace chalcopyrite. Wall-rock alteration in the Tarz deposit is also simple and consists of dolomitization and minor silicification. Within the sulfide ore zones, structures consist of massive and vein types and textures consist of anhedral to euhedral granular and open space fillings. Pyrite has cubic form. Calcite occurs as patches in width. In vein ores, sphalerite is also fine-to coarse-grained with anhedral to euhedral. Galena fills vein and fracture. Calcite crystal is an important host mineral among the two hypogene stages. Microthermometric measurements from the Tarz deposit show that ore minerals were deposited at low-temperature (85-196°C), with moderate salinities (18–22.5 wt.% NaCl). The Tarz Zn–Pb deposit has many similarities with the most important characteristics of the Mississippi Valley-type (MVT) deposits (characteristics such as tectonic setting, faults and fractures, the epigenetic nature of mineralization, ore structureand texture, the host rocks, wall-rock alteration and homogenization temperature of fluid inclusions). Discussion The Tarz Zn–Pb deposit is a stratabound, epigenetic hosted in Upper Permian-Lower Triassic (Rajabi et al., 2013) thick sequence of carbonate rocks (dolomitic limestone). Ore mineralogy of the Tarz deposit is relatively simple. The principal economic ore minerals are galena and sphalerite. Other minor minerals include pyrite with trace chalcopyrite. The gangue minerals are mainly dolomite, calcite and minor quartz. Textural evidence shows that the ore minerals have been mostly replaced by carbonate host rocks. Smithsonite and hydrozincite, malachite, hematite, goethite and covellite are secondary minerals that have developed from the primary hypogene Zn–(Fe–Pb) sulfides through weathering. Gossan coexists with Pb–Zn sulfide ores and is usually located in the upper levels of the sulfide ores. This ore body is strata-bound and occurs along the fault. Based on crosscutting, overgrowth and replacement relationships, the paragenetic sequence of the Tarz deposit is shown. Calcite and dolomite constitute the carbonate matrix of the ore. Microthermometric measurements were performed on the primary two-phase (L-V) (the ratio of gas to liquid is 2–20%) inclusions larger than 5 μm in diameter that are interpreted as representing the fluids present at the time of hydrothermal mineral growth. The type of inclusions in Calcite is two-phase, liquid-rich that homogenize into a liquid state upon heating. Fluid inclusion shapes are elliptical, rod-shaped, round, or irregular. Homogenization temperatures (Th) values range from 85 to 196°C. The final ice melting temperatures (Tmice) values range from -14.2 to -20.2°C. Salinities of aqueous inclusions were calculated using Bodnar’s (1993) for the NaCl–H2O system and yielded 18–22.5 wt.%NaCl. Acknowledgments We appreciate the help of Mr. Bahreini and Ahmadi for offering facilities and sampling during field work. References Bodnar, R.J., 1993. Revised equation and table for determining the freezing point depression of H2O-NaCl solutions. Geochimica et Cosmochimica Acta, 57(3): 683–684. Rajabi, A., Rastad, E. and Canet, C., 2012. Metallogeny of cretaceous carbonate hosted Zn–Pb deposits of Iran: geotectonic setting and data integration for future mineral exploration. Internatinal Geology Review, 54(14):1649–1672. Rajabi, A., Rastad, E. and Canet, C., 2013. Metallogeny of Permian–Triassic carbonate-hosted Zn–Pb and F deposits of Iran: a review for future mineral exploration. Australian Journal of Earth Sciences, 60(2): 197–216.

Introduction Located in the NE Iran, the early Tertiary volcanic sequences host a vast stratabound Cu mineralization (manto type), which is likely to be significant economically (Samani, 2002). The Pirmardan copper deposit is located 130 km southwest of Shahrood and is classified as a manto type mineralization, hosted by altered andesite to trachyandesite, volcanic breccia and tuff. The host rock suffers from two kinds of local and regional hydrothermal alterations of sericite- carbonate, and propylitic, respectively. Sulfide minerals occur as disseminated vein and veinlet forms in the host rock. Manto mineralization type in the northeast and central Iran could be a new prospective for the copper deposits subsequence of the Cu porphyry deposits in Iran (Samani, 2002). Our studies focus on the mineralogy, geology, fluid inclusion and ore formation in an attempt to understand the characteristics of ore fluids and mechanisms of ore formation, and to develop exploration criteria for Pirmardan and similar occurrences in the northeast of Iran. Materials and methods Various rock types and alteration assemblages, and mineral paragenesis, were characterized by transmitted and reflected light microscopy, X-ray diffraction (XRD) and X-ray Fluorescence (XRF) analysis. Representative samples from drill holes were selected for fluid inclusion studies. Microthermometric measurements were carried out by the linkam stage for heating and freezing system at the Geological Survey of Iran (GSI). Results Several mineralized zones with the width of 0.5-20 m and length of 5-300 m have been found in the Pirmardan area. Mineralization occurs in the shape of vein and veinlet, breccia, stockwork and open space filling. The copper mineralization in the area occurs as strata bound and sulfide minerals are disseminated in the andesitic rock in a depth of 30 m up to 20 m thickness. The ore grade is about 2% and ore minerals include chalcocite, malachite, azurite, hematite, pyrite and chalcopyrite. Based on microscopic and macroscopic studies, the mineralization at the Pirmardan area is divided into two stages: hypogene stage, which is further subdivided into early and main stages; and supergene stage, which includes sulfidation and oxidation stages. Given the results of the geological and geophysical investigations carried out in the study area, six exploration bore-holes were suggested to be drilled to a depth ranging from 34 to 45 m. The results of drilling confirmed a level of mineralization containing amounts of copper. Mineralization in the depth of (0 to 28 m) occurs in the forms of vein and veinlet with a disseminated texture. Fluid inclusions in the veinlet of calcite from the main hypogene stage occur typically as isolated bodies. Homogenization temperatures are between 117 and 400 ºC. The final melting temperatures are between -0.8 and -9.2 ºC, giving apparent fluid salinities of 1.3 to 13.0 % weight NaCl equivalent. Discussion The study area is located in the Pirmardan district along with other manto type Cu deposits in the northeast of Iran that occur mostly in the felsic-intermediate volcanic and pyroclastic rocks of Tertiary range. The geological studies in this area indicate the two main hydrothermal events of copper mineralization and alterations resulting from circulating heated waters (e.g. Oyarzun et al., 1998). It is likely that both of the hydrothermal events have contributed to extensive mineralization in shallow and deeper parts of the subsurface area. Mineralization in the shallow depths is controlled by local faults and fractures. These fractures are mineralized by chalcosite, malachite, pyrite, chalcopyrite and Fe-oxides minerals associated with veinlets of calcite and quartz. Microthermometric data indicate that the ore formation was mainly related to the low to moderate temperatures (117-400 °C) and salinities (1.3 to 13 wt.% NaCl). The widespread salinity in the Pirmardan area could be explained by the processes of boiling. Mixing and boiling are two important processes during the ore formation in the hydrothermal systems (Oyarzun et al., 1998). The occurrence of hydrothermal breccias and coexistence of fluid-rich and vapor-rich inclusions (Oyarzun et al., 1998) in calcite indicate that boiling is one of the main ore-forming processes, especially during the main hypogene stage in the Pirmardan district. Overall, the host rocks, alteration, ore mineralogy, ore structure and texture and fluid inclusions characteristics in the Pirmardan district are similar to those deposits belonging to the Cenozoic manto type deposits in the South America (Kojima et al., 2003; Wilson and Zentilli, 2006). Acknowledgments I would like to thank Mr. Shahilani, manager of the Armaghan Padideh Kashan Company for his kind cooperation for providing information of the Pirmardan area and collecting samples from the area. I would like to thank M. Zanboori for his kind cooperation in the field of geology and for preparing the geological map of the Pirmardan area. Furthermore, also I would like to thank F. Padiar and N. Ebrahimi from the Geological Survey of Iran for their assistance in the thermobarometry analysis. References Kojima, S., Astudillo, J., Rojo, J., Trista, D. and Hayashi, K.I., 2003. Ore mineralogy, fluid inclusion, and stable isotope characteristics of stratiform copper deposits in the coast Corillera of northern Chile. Mineralium Deposita, 38(2): 208–216. Oyarzun, R., Ortega, L., Sierra, J., Lunar, R. and Oyarzun, J., 1998. Cu, Mn, and Ag mineralization in the Quebrada Marquesa Quadrangle, Chile: the Talcuna and Arqueros districts. Mineralium Deposita, 33(6): 547–559. Samani, B., 2002. Metallogenic of the Manto type copper deposit. 6th Geological Society of Iran Conference, Shahid Bahonar University, Kerman, Iran. Wilson, N.S.F. and Zentilli, M., 2006. Association of pyrobitumen with copper mineralization from the Uchumi and Talcuna districts, central Chile. International Journal of Coal Geology, 68(3):158–169.

Introduction The Cheshmeh Khuri area is located in the north of the Lut Block volcanic–plutonic belt, in eastern Iran, about 111 Km northwest of the city of Birjand. Extensive Tertiary magmatic activity in the Lut Block, is spatially and temporally associated with several types of mineralization events (Karimpour et. al., 2012). The episode of Middle Eocene to lower Oligocene (42–33 Ma) was very important in terms of magmatism and mineralization (Karimpour et. al., 2012). The North Khur area includes numerous cases of Cu±Pb±Zn vein-type mineralization, such as the Shikasteh Sabz, Mir-e-Khash, Rashidi, Shurk, Ghar-e-Kaftar, Howz-e-Dagh, as well as kaolin deposit (Cheshmeh Khuri area). We present and discuss alteration, ore petrography, geochemistry, fluid inclusion micro thermometry, and sulfur isotope geochemistry, which help clarify the ore genesis of the Cheshmeh Khuri area. Materials and methods The present study involves detailed field work and study of thin and polished sections from the intrusive rocks and ore samples under the optical microscope. Metal concentrations were analyzed at the IMPRC laboratory of Iran using the ICP-OES techniques on fifteen samples. Five samples were analyzed for Fire Assay analysis and four samples for XRD analysis at IMPRC laboratory of Iran. Twelve spot analyses (microanalyses) were performed on an X-ray Analytical Microscope at IMPRC laboratory. Doubly polished wafers (150 μm thick) were prepared from five samples taken from surface and trenches. Micro thermometric measurements were carried out using a Linkam THM 600 heating–freezing stage mounted on an Olympus TH4–200 microscope stage at the Ferdowsi University of Mashhad, Iran. Two pyrite samples from quartz-sulfide veinlet were analyzed for the sulfur isotope compositions after careful hand picking and purification at Iso–Analytical limited, United Kingdom. Discussion and results The main alterations consists of propylitic, argillic, quartz-sericite-pyrite and silicified. The mineralization is mainly observed as vein and is disseminated in quartz-sericite-pyrite, argillic- silicified and propylitic alteration zones and is disseminated in the argillic alteration zone. Pyrite is the only primary sulfide mineral in the area. Due to the great influence of weathering processes on the primary ore, secondary sulphide and oxide mineralization (malachite, azurite, chalcocite, covellite, goethite, and hematite) are widely spread and have finally created lithocap (Sillitoe, 1993; Sillitoe et. al., 1998). The maximum anomalies of copper (654 ppm) and lead (1622 ppm) are associated with quartz-sericite-pyrite alteration. Primary fluid inclusions of quartz in paragenesis with mineralization in quartz-sericite-pyrite zone, argillic-silicified zone and calcite in paragnesis with mineralization in propylitic zone have an average of homogenization temperatures of 321°C, 305 °C and 263 °C, respectively. Based on freezing studies, the average calculated temperature of last melting point of these is equal to 12, 11.6 and 7.9 wt.% NaCl, respectively. Homogenization temperature and salinity of the fluids shows a shifting trend from relatively high in quartz-sericite-pyrite zone to relatively low homogenization temperatures in the propylitic zone, which can be due to physicochemical changes in the fluid such as cooling and mixing with meteoric water (Naden et al. 2005). According to the textural evidence, boiling has also been effective during the evolution of the fluid. The amount of δ34S for pyrite has a range between 2.35 to 2.46 and the amount of δ34 equilibrium with pyrite has a range of 1.25 to 1.36 that show a magmatic origin for sulfur (Ohmoto and Rye, 1979; Lesage, 2011). The expansion of propylitic and argillic alteration zones on the surface, the limited quartz-sericite -pyrite zone, the absence of potassic alteration, the existence of lithocap, geochemical anomalies, the range of temperature and salinity of the fluid inclusion can be indicative of the upper part of a porphyry copper system. References Karimpour, M.H., Malekzadeh Shafaroudi, A., Stern, C.R. and Farmer, L., 2012. Petrogenesis of Granitoids, U–Pb zircon geochronology, Sr–Nd isotopic characteristic and important occurrence of Tertiary mineralization within the Lut Block, Eastern Iran. Journal of Economic Geology, 4(1): 1–27. (in Persian with English abstract) Lesage, G., 2011. Geochronology, Petrography, Geochemical constrain, and fluid characterization of the Buritica gold deposit. Ph.D. thesis, University of Alberta, Alberta, United State America, 152 pp. Naden, J., Killias, S.P. and Darbyshire, D.P.F., 2005. Active geothermal system with entrained seawater as modern analogs for transitional volcanic-hosted massive sulfide and continental magmato-hydrothermal mineralization: the example of Milos Island, Greece. Geology, 33(7): 541–544. Ohmoto, H. and Rye, R.O., 1979. Isotopes of sulfur and carbon: In: H.L. Barnes (Editor), Geochemistry of Hydrothermal Ore Deposits, Wiley Interscience, New York, pp. 509–567. Sillitoe, R.H., 1993. Epithermal models: Genetic types, geometrical controls and shallow features. Geological Association of Canada, Special Paper, 40(1): 403–417.

Introduction The Tappeh-Khargoosh area is located at the 15 km SW of Ardestan, in the middle section of the Urumieh-Dokhtar magmatic arc (Aghanabati, 2004). Exploration in the study area began in 2006 by Kani Pajohan-e- Spadana Company and continued in detail by the Ardestan Copper-Gold Company. Their exploration activities consist of preparing the geological map (1:5000 in scale), drilling trenches and boreholes. Also minor extraction has been done. In this paper, our focus is on mineralogy, alteration, geochemistry and fluid inclusion of the Tappeh-Khargoosh deposit for determining the genesis of mineralization. The results of this study can be used for more exploration in the study and adjacent areas. Methodology Samples collected along a traverses perpendicular to the mineralized veins and their alteration haloes. The geometry, morphology, mineralogy and texture of mineralization were examined. After careful microscopic studies, 7 samples were analyzed by the XRF method in the laboratory of the Tarbiat Modarres University and Iranian Mineral Processing Research Center (IMPRC) in Karaj. Six thin-polished sections and 8 polished sections were examined. Also, 32 samples of mineralized and altered zones were analyzed by Inductively Coupled Plasma with optical emission spectrometer (ICP-OES) in IMPRC. Six samples were analyzed for gold by Atomic Absorption Spectroscopy (A.A.S) method in the Kimia Pajoh Alborz laboratory. Three double polished sections prepared from mineralized quartz vein and micro thermometric studies had been analyzed by a model HF-S90 microscope in the University of Isfahan. For detail understanding of mineral composition and determination of some fine and rare minerals, the electron microprobe analyzing (EMPA) technique (model SX100) is used in IMPRC. Discussion and results The Tappeh-Khargoosh deposit consist of quartz vein and veinlets which occur as open space filling in Eocene andesite and dacite. The mineralized veins mainly occur in the fault zones. The subparallel fault systems of dextral strike sleep Qom-Zefreh crustal scale fault (Tajmir Riahi et al., 2012) has had the main role in localization of mineralizing fluids. The alteration mainly consist of silicificaion, propylitization with minor sericitization and argillization represented as vein-veinlets, dissemination and pervasively in host volcanics. These alteration assemblages are indicative of near neutral to little alkaline hydrothermal fluids (Simmons et al., 2005). The silicic alteration has occurred in a wide range of pH and temperature, while the argillic alteration has occurred in low temperature and a wide range of pH. So where the silicic and argillic alterations have occurred together, the temperature of the causing fluid must be lower in the range of clay mineral stability field (Robb, 2005). The fluid inclusion in the quartz shows the low temperature (137-194˚C) and low to medium salinity (4-12.5 %) which coincide with low to medium sulfidation epithermal deposit conditions. According to fluid inclusion data, bisulfides were the main ligand for metals transportation. The absence of halite/sylvite daughter minerals in fluid inclusions and low salinity of fluid inclusions show that the chloride complexes not act as effective ligands. Opposed to high sulfidation epithermal deposits in which the magmatic waters are common, in the low sulfidation type, the meteoric waters are dominant (Foster, 1991; Vahabi Moghadam, 1993). Dilution by cold and low salinity meteoric water has the main role in mineral deposition. Pyrite, chalcopyrite, bornite, chalcocite and native gold are the primary minerals and hematite, goethite, covellite, chalcocite, cuprite, malachite, chrysocolla, azurite and atacamite are the secondary minerals, which have occurred as veinlets, open space filling, colloform, amygdal filling and dissemination in quartz vein and host rocks. Fine grain gold had be seen in the colloidal secondary Fe-oxides, which indicate that the gold probably occurred primarily in sulfide minerals and was released in the supergene process. According to microprobe analysis, Ag was measured as impurity in chalcocite. These features coincide with high correlation coefficient between precious metals and copper. So, the Cu can be used as a pathfinder element for gold exploration in this and adjacent areas. The abundance of Cu-bearing secondary minerals in the surface, indicate that the Cu has not leached effectively as a result of the little amount of pyrite and aridity of the area. In this condition, Cu which was created by oxidation of primary Cu minerals was fixed in the surface as silicate, carbonate and oxide minerals (Chavez, 2000). Geology, geometry, texture and structure, geochemistry, alteration schema, fluid inclusion and mineralogical data of the Tappeh-Khargoosh make it similar to low sulfidation (L.S) epithermal deposits. References Aghanabati, A., 2004. Geology of Iran. Geological Survey of Iran Publications, Tehran, 709 pp. (in Persian) Chavez, W.X., 2000. Supergene oxidation of copper deposits: Zoning and distribution of copper oxide minerals. Society of Economic Geologists Newsletter, 41(1): 10–21. Foster, R.P., 1991. Gold metallogeny and exploration. Springer, London, 431 pp. Robb, L., 2005. Introduction to ore- forming processes. Blackwell Publication, Australia. 373 pp. Simmons, S.F., White, N.C. and John, D.A., 2005. Geological characteristics of epithermal precious and base metal deposits. In: J.W. Hedenquist, J.F.H. Thompson, R.J. Goldfarb and J.P. Richard (Editors), Economic Geology, 100th Anniversary Volume: 1905-2005. Society of Economic Geologists, Littleton, Colorado, pp. 485–522. Tajmir Riahi, Z., Beigi, S., Safaei, H. and Nadimi, A., 2012. Identification active faults and seismic tectonic Shahreza area. 31th Geosciences Conference, Geological survey and mineral explorations, Tehran, Iran. (in Persian) Vahabi Moghadam, B., 1993. Petrographic and petrology metamorphic- magmatic rocks south of Nain. M.Sc. Thesis, University of Tarbiat Moalem, Tehran, Iran, 250 pp.

Introduction Fluid inclusions are small, usually microscopic, volumes of pore fluid, which are crystallographically trapped in rocks during diagenesis or fracture healing processes. Nowadays, various techniques are used for resource exploration. Application of a fluid inclusion is one of these methods that has been developed for mineral, geothermal, and petroleum reservoir exploration. The study of fluid inclusions represents our most reliable source of information on the temperature, pressure, and fluid composition data of the ore fluid, and it is one of the most important tools for research into the economic geology and genesis of ore deposits (Moon, 1991). To achieve these goals, transparent and polished slabs of rock material are prepared and optically studied with a petrographic microscope. Samples are viewed under transmitted plane-polarized white light as well as under reflected ultraviolet or blue-violet illumination. During the fluid inclusion petrography, the volume fractions of phases are routinely estimated at room temperature to deduce whether assemblages of cogenetic inclusions were originally trapped from a one-phase or a multi-phase pore fluid. In the present research study, the microthermometric properties of the fluid inclusion data through pressure, temperature, and salinity diagrams were computed by geometrical modeling of fluid inclusion (Bakker and Larryn, 2006). The proposed method provides a quick and low cost technique to preliminarily investigate the microthermometric parameters of the fluid inclusion. To evaluate the proposed geometrical model, the Mehdiabad Pb-Zn deposit is selected as the case study. The Mehdiabad Pb-Zn deposit is located at the Yazd-Anarak metallogenic belt, 110 km southeast of Yazd, in the Central Iran structural zone. The host rocks of the deposit consist of lower Cretaceous silty limestone and dolomite. The main occurrences are the Calamine mine (CM), the Black-Hill ore (BHO), the East Ridge (ER) and the Central Valley Orebody (CVOB). The ore body consists of a primary sulfide ore and a supergene non-sulfide ore, the latter one having been mined at CM (Ghasemi, 2007; Rajabi et al., 2012). Materials and methods The shape and geometry of fluid inclusion are one of the most important parameters, which were applied to estimate 3D degree of filling and find the useful information about temperature, pressure, salinity and depth of trapping without using time-consuming and costly heating-cooling operation. Inclusions in normal thick-sections are rotated stepwise and their projected areas and area-fractions are plotted against rotation angle. The outputs are systematically related to inclusion orientation, inclusion shape, and filling degree. The dependency on orientation is minimized when area fractions are measured at the position where the inclusions project their largest total areas. The shape factor is employed to present a new objective classification of inclusion projections, based on the extracted parameters from digital image processing (Bakker and Larryn, 2006). In this research, Mehdiabad Pb-Zn deposit has been chosen to evaluate the proposed method. Based on the fluid inclusion petrography, four fluid inclusion types are observed: 1) L+V; 2) L+L; 3) L; and 4) V; L+V phase is the most popular. After preparing 2D image of sections, 2D and 3D degree of fills were calculated by measuring the areas of total, bubble, and spot of fluid inclusion and computing the third dimension (Z) of fluid inclusion. Four geometrical models of volume fractions are defined, including cylinder, tetragonal prism, truncated cone, hexagon, and ellipsoid (Bakker and Larryn, 2006; Hossein Morshedy et al., 2008). In this case study, 3D proper models of the fluid inclusions are selected, depending on its geometry (hexagonal or ellipsoid). Then 2D degrees of filling (area fraction) is converted to 3D degrees of filling (volume fraction). The geometrical modeling results are well matched with computational outputs. Results and discussion In this research, the ratios of area to volume fractions in geometrical and computational modelling were calculated 0.75 and 0.77, respectively. In the Mehdiabad Pb-Zn deposit, the main geometrical shapes of fluid inclusions were followed up the hexagonal prism with hexagonal pyramids and ellipsoid models. 3D geometrical modeling of fluid inclusion showed vapor fraction, 25% and density, 0.7 g/cm3, which the microthermometric and other parameters were obtained homogenization temperature nearly 100-200 °C (average of 150 °C), pressure between 400-500 ATM, formation temperature about 250-350 °C, salinity within a range of 10 to 15 wt.% NaCl equiv. and depth of mineralization 150-200 m. This finally achieved results have a high similarity with the typical carbonate-hosted Pb-Zn deposit. References Bakker, R.J. and Larryn, W.D., 2006. Estimation of volume fractions of liquid and vapor phases in fluid inclusions, and definition of inclusion shapes. American Mineralogist, 91(1): 635–657. Ghasemi, M., 2007. Genesis of Mehdiabad Pb–Zn deposit and comparing with other Pb–Zn deposits. M.Sc. Thesis, Research Institute for Earth Science, Geological Survey of Iran, Tehran, Iran, 238 pp. (in Persian with English abstract) Hossein Morshedy, A., Mojtahedzadeh, H. and Kohsary, A.H., 2008. Measuring microthermic parameters of fluid inclusion with studying their geometries and models, case study: Mehdiabad Pb–Zn deposit. 15th Symposium of Crystallography and Mineralogy of Iran, Ferdowsi University of Mashhad, Mashhad, Iran. (in Persian with English abstract) Moon, K.J., 1991. Application of fluid inclusions in mineral exploration. Journal of Geochemical Exploration, 42(1): 205–221. Rajabi, A., Rastad, E. and Canet, C., 2012. Metallogeny of Cretaceous carbonate-hosted Zn–Pb deposits of Iran: geotectonic setting and data integration for future mineral exploration. International Geology Review, 54(14): 1649–1672.

Introduction Fluorite ore deposits are classified into three main groups: (1) magmatic deposits, (2) structures related deposits, and (3) sedimentary deposits (Dill, 2010). More than 30 fluorite occurrences with approximately 1.35 million tons of reserves have been recognized in Iran (Miller, 2014). Bagher Abad and Darreh Badam fluorite ore deposits, located in the southeast of Delijan (Markazi province) occur between the central Iran structural zone from the north and the Sanandaj-Sirjan structural zone from the south. The geology of the area is dominated by folded and faulted structures of Jurassic carbonates and shales (Thiele et al., 1968). The main host rocks for fluorite mineralization in the studied area are the Lower-Upper Jurassic carbonates and shales of Shemshak and Badamu Formations. Materials and Methods In this study, 70 samples from the various rock types including fluorite veins, host rocks and related alterations were collected. 25 thin- and polished thin-sections were prepared and studied to explain the mineralogy and paragenetic sequence of the ore body. Eight double-polished sections were also prepared for micro-thermometric analysis. The micro-thermometric analyses were conducted on primary fluid inclusions using Linkam THM600 heating-freezing stage connected to a TMS94 temperature controller and a liquid nitrogen pump (LNP) cooling system. Results The main host rocks for fluorite mineralization in the studied area are composed of the lower Jurassic slate and phyllite (Shemshak Formation) and the Middle to Upper Jurassic dolomitic limestone and calcareous sandstone (Badamu Formation). The main alterations associated with fluorite mineralization are sericitization, silicification and argillization. According to the fluid inclusions data, fluorite mineralization in Bagher Abad and Darreh Badam deposits were precipitated because of pressure reduction of ore bearing fluids and mixing of a primary moderate-salinity brine with less saline meteoric water. Estimation of trapping pressure-temperature of the mineralizing fluid in Bagher Abad fluorite deposit using the intersecting CO2 and H2O isochors for aqueous, aqueous-carbonic and carbonic fluid inclusions indicated that fluorite mineralization occurred at 180-260°C and 1-2 kbar pressure. According to the present study, circulation and upward flow of hydrothermal fluids (containing H2O and CO2) that originated from underlying altered bedrock provided appropriate conditions for increasing the solubility of metals and formation of halide (Cl¯ and F¯) metal complexes. Reaction with wallrock and gradual decrease in temperature due to mixing and dilution of the above-mentioned fluids with low-salinity meteoric water resulted in fluorite mineralization in favorable structures such as veins. Discussion Bagher Abad and Darreh Badam fluorite ore deposits are examples of epigenetic mineralizations which are not related to igneous activities in Iran. The mineralization is formed in nearly vertical veins, which are relevant to local fractures hosted in the Lower-Upper Jurassic carbonates and shales with east-west trend. The main ore textures are open-space fillings, breccias, veins and cavities associated with sericitic, silicic and argillic alterations. Micro-thermometric measurements were carried out on primary fluid inclusions in fluorite, calcite and barite minerals from both Bagher Abad and Darreh Badam deposits. Three types of fluid inclusions were distinguished: (1) two phase aqueous fluid inclusions (LV), (2) liquid (L) or vapor (V) mono phase inclusions, and (3) aqueous-carbonic (L1+L2+V) fluid inclusions. The first ice melting temperatures (Te) of two phase aqueous inclusions (LV) in fluorite, calcite and barite from Bagher Abad and Darreh Badam deposits vary between -32 to -15°C and -35 to -24°C, respectively, which represents a H2O+NaCl±KCl multiphase fluid (Van den Kerkhof and Hein, 2001). The last ice melting temperatures (Tmice) vary between -10.5 to -2.3°C and -12.0 to -5.6°C which are equal to salinities of 5.6-14.7 and 8.3-15.2 wt% NaCl equivalent for Bagher Abad and Darreh Badam deposits, respectively. The final homogenization temperatures (Thtotal) vary between 127 to 188 °C and 176 to 270°C for Bagher Abad and Darreh Badam deposits, respectively. The CO2 melting temperatures (TmCO2) of aqueous-carbonic inclusions in fluorite, calcite and barite show a range of -58.3 to -56.6°C which suggests CH4 and/or N2 impurities (Burruss, 1981). The clathrate melting temperatures (Tmclath) ranging from -6.0 to +1.0°C represent salinities between 5.5 to 18.2 wt% NaCl equivalent for both Bagher Abad and Darreh Badam fluorite deposits. References Burruss, R.C., 1981. Analysis of phase equilibria in C–O–H–S fluid inclusions. In: L.S. Hollister and M.L. Crawford (Editors), Fluid inclusions: applications to petrology. Mineralogical Association of Canada Short Course Series, Ontario, pp. 39–74. Dill, H.G., 2010. The chessboard classification scheme of mineral deposits: mineralogy and geology from aluminum to zirconium. Earth-Science Reviews, 100(1): 1–420. Miller, M.M., 2014. Fluorspar. In: S.M. Kimball (Editor), Mineral commodity summaries 2014. U.S. Geological Survey, Reston, Virginia, pp. 56–57. Thiele, O., Alavi, M., Assefi, R., Hushmand-zadeh, A., Seyed-Emami, K. and Zahedi, M., 1968. Explanatory text of the Golpaygan quadrangle map, scale 1:250,000. Geological Survey of Iran, Geological quadrangle E7, Tehran, 24 pp. Van den Kerkhof, A.M. and Hein, U.F., 2001. Fluid inclusion petrography. Lithos, 55(1–4): 27–47.

Introduction Nowadays, more than half of the word’s copper production is obtained from porphyry copper deposits, large (greater than 100 Mt), low- to moderate-grade, disseminated, stockwork-veinlet, carrying at least trace elements, such as molybdenum, gold, and silver (Sillitoe, 1972). Porphyry Cu systems are related to granitoid porphyry intru¬sions and adjacent wall rocks and most of them form at convergent plate margins (John et al., 2010). The deposits are often localized within calc-alkaline porphyry magmatic systems in subduction zone settings. Some PCDs have been formed in post-subduc¬tion settings. Ahar-Arasbaran metallogenic zone is one of the most productive metallogenic zones in Iran. Mineralization in the area is mainly associated with Tertiary magmatic events. In order to perform a comparative study of mineralization, Sungun and Kighal porphyry copper deposits (PCDs) were selected. The Sungun copper deposit is located in the north Varzaqan and the Kighal copper deposit lies 10 km to the south of the Sungun PCD (Calagari, 2003; Calagari, 2004). As recent studies show there are some similarities between the Sungun and Kighal deposits in terms of the parent intrusions, the host rocks, age and geological setting. However, the grade of copper in the Sungun PCD is 0.62 % Cu and in the Kighal PCD is 0.2 % Cu. Therefore, what are the key factors that have made the Kighal PCD sub-economic? Material and methods Geochemical, fluid inclusion, and mineralogical studies were done on collected samples of the two porphyry copper deposits. In order to mineralogically study the Sungun and Kighal PCDs, 100 thin and polished thin sections were prepared. Eleven doubly polished sections of different quartz veins of the two PCD borehole samples were prepared for fluid inclusion studies. The measurements of 205 fluid inclusions were conducted at the Iranian Mineral Processing Research Center (IMPRC) by ZEISS microscope and Linkam TMH600, at temperature limits of -196 to +600 °C. The precision was ±0.6 °C at 414 °C (melting point of Cesium nitrate), and ±2°C at -94.3 (melting point of n-Hexane). SPSS 17 and Flincor computer programs (Brown, 1989) were used for data analysis. Discussion and Results In addition to some similarities of parent intrusions and host rocks (Hassanpour, 2010), there are similar fluid inclusion types and even nearly identical salinity and homogenization temperatures in these deposits (Simmonds, 2013). However, some differences in geochemical and mineralogical features, such as different low zonality index, less sulfide minerals and CO2 contents of the Kighal PCD, are notable. Some researchers have pointed out erosion (Hassanpour, 2010) and uplifting (Simmonds, 2013) as the main reasons for the sub-economic nature of the Kighal (non-productivity), comparison of Moho depth in the two deposits shows a greater crustal thickness in the Sungun PCD area (Fig. 10). The thickness of the lower crust is thought to be critical for governing arc mineralization potential, because it leads to an increase of the amount of water, metal, sulfur in adakitic magma forming arc-related bodies that is known to affect the origin of more productive (economic) porphyry copper deposits. Also low-CO2 fluid inclusions of the Kighal can have originated from a CO2-rich fluid immiscibility at depth (Simmonds, 2013). Lack of CO2 can inhibit (delays) bulk volatile saturation and in turn boiling, which influences the efficiency of metal removal from melt as well (Candela, 1997). CO2 contents of mineralizing fluids is important in increasing of pH during boiling event and ore deposition. The non-productivity of the Kighal PCD may have resulted from all these factors. Acknowledgement This work was supported by Bu-Ali Sina University and Iranian Mines and Mining Industries Development and Renovation Organization (IMIDRO). The authors would like to thank of the Sungun and Ahar copper companies. Special thanks to all the staff for their kind help. Thanks to the reviewers for their suggestions. References Brown, P.E., 1989. FLINCOR; a microcomputer program for the reduction and investigation of fluid-inclusion data. American Mineralogist, 74(11): 1390–1393. Calagari, A.A., 2003. Stable isotope (S, O, H and C) studies of the phyllic and potassic–phyllic alteration zones of the porphyry copper deposit at Sungun, East Azarbaidjan, Iran. Journal of Asian Earth Sciences, 21(7): 767–780. Calagari, A.A., 2004. Fluid inclusion studies in quartz veinlets in the porphyry copper deposit at Sungun, East-Azarbaidjan, Iran. Journal of Asian Earth Sciences, 23(2): 179–189. Candela, P.A., 1997. A review of shallow, ore-related granites: textures, volatiles, and ore metals. Journal of Petrology, 38(12): 1619–1633. Hassanpour, S., 2010. Metallogeney and mineralization of Cu-Au in Arasbaran Zone, NW of Iran. Ph.D. Thesis, Shahid Beheshti University, Tehran, Iran, 320 pp. John, D., Ayuso, R., Barton, M., Blakely, R., Bodnar, R., Dilles, J., Gray, F., Graybeal, F., Mars, J. and McPhee, D., 2010. Porphyry copper deposit model, chap. B of Mineral deposit models for resource assessment, US Geological Survey Scientific Investigations Report, 169 pp. Sillitoe, R.H., 1972. A plate tectonic model for the origin of porphyry copper deposits. Economic geology, 67(2): 184–197. Simmonds, V., Calagari, A.A. and Kyser, K., 2013. Fluid inclusion and stable isotope studies of the Kighal porphyry Cu–Mo prospect, East-Azarbaidjan, NW Iran. Arabian Journal of Geosciences, Fluid inclusion and stable isotope studies of the Kighal porphyry Cu–Mo prospect, East-Azarbaidjan, NW Iran. Arabian Journal of Geosciences, 8(1): 1–17.