Fluid evolution and ore genesis of Cu–Pb–Zn veins in the Panjiaduan deposit, Great Xing’an Range, NE China: evidence from fluid inclusion and H–O–He–Ar isotopes
1
Citation
89
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract The southern Great Xing’an Range (SGXR), located in the eastern segment of the Central Asian Orogenic Belt (CAOB), is one of the most economically important Cu–Mo–Fe–Sn–Pb–Zn–Ag metallogenic provinces in China. The newly discovered Panjiaduan Cu–Pb–Zn deposit (9.3 Mt; at 1.36% Cu, 2.90% Pb, 3.80% Zn and 38.12 g/t Ag), located in the SE segment of the SGXR, is primarily hosted in fracture zones in volcanic rocks and granodiorite of the Manitu Formation. Four paragenetic stages of metallic mineralization are identified: (I) quartz-pyrite-arsenopyrite; (II) quartz-polymetallic sulphide; (III) quartz-galena-sphalerite-argentite; and (IV) quartz-calcite-minor sulphide. The hydrothermal quartz contains three types of primary fluid inclusion (FIs): vapour-rich two-phase liquid-vapour (LV-type), liquid-rich two-phase liquid-vapour (VL-type) and three-phase liquid-vapour-solid FIs (SL-type). Stages I and II contain all types with homogenization temperatures ( T h ) of 324–386 °C and 276–334 °C as well as salinities of 0.7–38.0 wt% and 0.9–34.7 wt%, respectively, whereas stage III is composed of VL- and LV-type FIs with T h of 210–269 °C and salinities of 0.5–7.2 wt%. Only VL-type FIs occur in stage IV, with T h of 139–185 °C and salinities of 1.6–4.2 wt%. The δ 18 O H2O and δD values vary from −15.7 to 2.6‰ and −132.7 to −110.2‰, respectively, indicating predominant meteoric water with an initial magmatic source. The He–Ar isotopic compositions of the pyrite inclusions from the Panjiaduan Cu–Pb–Zn veins suggest that fluids were derived from the crust.Keywords:
Arsenopyrite
Abstract The Xiuwenghala gold deposit is located in the Beishan Orogen of the southern Central Asian Orogenic Belt. The vein/lenticular gold orebodies are controlled by Northeast‐trending faults and are hosted mainly in the brecciated/altered tuff and rhyolite porphyry of the Lower Carboniferous Baishan Formation. Metallic minerals include mainly pyrite and minor chalcopyrite, arsenopyrite, galena, and sphalerite, whilst nonmetallic minerals include quartz, chalcedony, sericite, chlorite, and calcite. Hydrothermal alterations consist of silicic, sericite, chlorite, and carbonate. Alteration/mineralization processes comprise three stages: pre‐ore silicic alteration (Stage I), syn‐ore quartz‐chalcedony‐polymetallic sulfide mineralization (Stage II), and post‐ore quartz‐calcite veining (Stage III). Fluid inclusions (FIs) in quartz and calcite are dominated by L‐type with minor V‐type and lack any daughter mineral‐bearing or CO 2 ‐rich/‐bearing inclusions. From Stages I to III, the FIs homogenized at 240–260°C, 220–250°C, and 150–190°C, with corresponding salinities of 2.9–10.9, 3.2–11.1, and 2.9–11.9 wt.% NaCl eqv., respectively. The mineralization depth at Xiuwenghala is estimated to be relatively shallow (<1 km). FI results indicate that the ore‐forming fluids belong to a low to medium‐temperature, low‐salinity, and low‐density NaCl‐H 2 O system. The values decrease from Stage I to III (3.7‰, 1.7–2.4‰, and −1.7 to 0.9‰, respectively), and a similar trend is found for their values (−104 to −90‰, −126 to −86‰, and −130 to −106‰, respectively). This indicates that the fluid source gradually evolved from magmatic to meteoric. δ 34 S values of the hydrothermal pyrites (−3.0 to 0.0‰; avg. −1.1‰) resemble those of typical magmatic/mantle‐derived sulfides. Pyrite Pb isotopic compositions ( 206 Pb/ 204 Pb = 18.409–18.767, 207 Pb/ 204 Pb = 15.600–15.715, 208 Pb /204 Pb = 38.173–38.654) are similar to those of the (sub)volcanic ore host, indicating that the origin of ore‐forming material was mainly the upper crustal (sub)volcanic rocks. Integrating evidence from geology, FIs, and H–O–S–Pb isotopes, we suggest that Xiuwenghala is best classified as a low‐sulfidation epithermal gold deposit.
Sericite
Arsenopyrite
Silicic
Chalcedony
Cassiterite
Ore genesis
Magmatic water
Cite
Citations (5)
Microthermomemc techniques were applied to samples from mantos and veins in the Hualgayoc District, Peru. Mineralisation in the district is hosted mainly in rocks from the Hualgayoc group (Mesozoic marine sedimentary and volcanic rocks). Primary and secondary inclusions in sphaleriteand gangue minerals were examined petrographically and their homogenisation and freezing temperatures measured. Three stages of sphalerite, with intermittent deposition of quartz, calcite and rhodocrosite are recognized. The results indicate that mineralisation took place at temperatures from about to above 350°C; the lowest values corresponding to vein mineralisation and the highest to the mantos. The highest apparent salinity values were observed in the manto samples (more than 16% NaCl) in contrast to lower salinities (4.3% NaCl) measured in one sphalerite sample from the San Filipe Vein. From the Mantos area to the north and the east, a trend of decreasing temperature and salinity exists. No evidence of boiling was observed in the sphalerite samples; however, boiling may have occurred during deposition of quartz and in the veins.
Deposition
Cite
Citations (0)
Molybdenite
Stockwork
Cassiterite
Hypogene
Arsenopyrite
Base metal
Sericite
Argillic alteration
Porphyritic
Wolframite
Polymetallic replacement deposit
Metallogeny
Cite
Citations (0)
Arsenopyrite
Massif
Prospecting
Paragenesis
Cite
Citations (0)
Arsenopyrite
Cite
Citations (59)
Eunjeok Au–Ag deposits are situated in the Yeongam district, Cheollanamdo-province, South Korea. They are genetically related to the Bulgugsa magmatic event (ca. 110–60 Ma), caused by the transition in the subduction direction and style of the Izanagi Plate. Three gold- and silver-bearing hydrothermal veins filled the fractures of the Cretaceous rhyolitic tuff. The major ore minerals were arsenopyrite (31.47–32.20 at.% As), pyrite, chalcopyrite, sphalerite (8.58–10.71 FeS mole%) and galena with minor amounts of electrum (62.77–78.15 at.% Au), native silver, and argentite. Sericitization was dominant in the alteration zone. The various textures of quartz veins (i.e., breccia, crustiform, comb, and vuggy) may indicate the formation of an epithermal environment. The auriferous fluids with the H2O–NaCl system have homogenization temperatures and salinities of 204 °C to 314 °C, less than 10 wt.% equiv. NaCl, and experienced mixing (dilution and cooling) events during mineralization. Considering the characteristics of the geologic setting, major fault system, and host rock, the Eunjeok Au–Ag deposit within the Yeongam district tends to share the general geologic characteristics of Haenam–Jindo epithermal mineralization episodes. However, the age of gold–silver mineralization (86.0 Ma) is older than that of Haenam–Jindo epithermal mineralization episodes (<70.3 Ma), implying some differences exist in the genetic sequence of extensional characteristics caused by transcurrent Gwangju–Yeongdong faults.
Breccia
Arsenopyrite
Cite
Citations (1)