scholarly journals Ore-Fluid Evolution of the Sizhuang Orogenic Gold Deposit, Jiaodong Peninsula, China

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 190 ◽  
Author(s):  
Yu-Ji Wei ◽  
Li-Qiang Yang ◽  
Jian-Qiu Feng ◽  
Hao Wang ◽  
Guang-Yao Lv ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Gold Deposit ◽  
Late Stage ◽  
Gold Mineralization ◽  
Early Stage ◽  
Main Stage ◽  
Jiaodong Peninsula ◽  
Wide Range ◽  
Homogenization Temperatures

The Sizhuang gold deposit with a proven gold resource of >120 t, located in northwest Jiaodong Peninsula in China, lies in the southern part of the Jiaojia gold belt. Gold mineralization can be divided into altered rock type, auriferous quartz vein type, and sulfide-quartz veinlet in K-feldspar altered granite. According to mineral paragenesis and mineral crosscutting relationships, three stages of metal mineralization can be identified: early stage, main stage, and late stage. Gold mainly occurs in the main stage. The petrography and microthermometry of fluid inclusion shows three types of inclusions (type 1 H2O–CO2 inclusions, type 2 aqueous inclusions, and type 3 CO2 inclusions). Early stage quartz-hosted inclusions have a trapped temperatures range 303–390 °C. The gold-rich main stage contains a fluid-inclusion cluster with both type 1 and 2 inclusions (trapped between 279 and 298 °C), and a wide range of homogenization temperatures of CO2 occurs to the vapor phase (17.6 to 30.5 °C). The late stage calcite only contains type 1 inclusions with homogenization temperatures between 195 and 289 °C. With evidences from the H–O isotope data and the study of water–rock interaction, the metamorphic water of the Jiaodong Group is considered to be the dominating source for the ore-forming fluid. The ore-fluid belonged to a CO2–H2O–NaCl system with medium-low temperature (160–360 °C), medium-low salinity (3.00–11.83 wt% NaCl eq.), and low density (1.51–1.02 g/cm3). Fluid immiscibility caused by pressure fluctuation is the key mechanism in inducing gold mineralization in the Sizhuang gold deposit.

Hydrothermal zircon and baddeleyite in Val-d'Or Archean mesothermal gold deposits: characteristics, compositions, and fluid-inclusion properties, with implications fortiming of primary gold mineralization

1993 ◽  
Vol 30 (12) ◽  
pp. 2334-2351 ◽  
Author(s):  
Robert Kerrich ◽  
Robert King
Keyword(s):  
Fluid Inclusion ◽  
Gold Mineralization ◽  
Wall Rock ◽  
Gold Deposits ◽  
Southern Volcanic Zone ◽  
Primary Fluid ◽  
Inheritance Model ◽  
Homogenization Temperatures ◽  
Host Rocks

Zircon and baddeleyite occur within quartz–tourmaline veins at four gold deposits in the Val-d'Or district of the Archean Abitibi Southern Volcanic Zone. Host rocks have experienced intense metasomatic enrichment of Zr, Hf, Y, and rare earth elements. The zircons contain primary inclusions of quartz, tourmaline, pyrite, albite, K-mica, scheelite, and gold, and gold occurs in primary fluid inclusions in zircons. Magmatic zircons in host rocks do not have this suite of inclusions; consequently a wall-rock inheritance model for the vein zircons is implausible. Compositionally, the zircons feature pronounced interzone and intergrain variations of Hf, Y, Yb, Th, and U, and sporadic anomalous Ce contents of ~ 1100 ppm, distinct from magmatic counterparts. Two principal types of primary fluid inclusion occur in the vein zircons. Type 1 H2O–CO2 inclusions have low salinities, variable quantities of CO2 and homogenization temperatures of 260–380 °C, and type 2 CO2 rich inclusions contain minor H2O and CH4. The vein zircons coprecipitated at 260–380 °C and ~ 2 kbar (1 kbar = 100 MPa) with coexisting minerals of undisputed hydrothermal origin, such as vein quartz and gold. In the Superior Province, mesothermal gold deposits are related in space and time to translithospheric structures that mark the diachronous accretion of allochthonous subprovinces from north to south between ~ 2710 and 2680 Ma. Consequently, vein zircon ages of ~ 2680 Ma record the primary mineralizing event, whereas aberrantly young ages for rutile, titanite, scheelite, and micas in the same vein systems, that scatter over 2630–2579 Ma, reveal the age of secondary remobilization events.

scholarly journals Carbonic fluids in the Hamadi gold deposit, Sudan: origin and contribution to gold mineralization

2017 ◽  
Vol 54 (5) ◽  
pp. 494-511 ◽  
Author(s):  
Xi-hui Cheng ◽  
Jiu-hua Xu ◽  
Jian-xiong Wang ◽  
Qing-po Xue ◽  
Hui Zhang
Keyword(s):  
Gold Deposit ◽  
Melting Temperature ◽  
Fluid Inclusions ◽  
Gold Mineralization ◽  
Narrow Range ◽  
Shear Zones ◽  
Quartz Veins ◽  
Wide Range ◽  
Homogenization Temperatures ◽  
Gold Bearing

The Hamadi gold deposit is located in North Sudan, and occurs in the Neoproterozoic metamorphic strata of the Arabian–Nubian Shield. Two types of gold mineralization can be discerned: gold-bearing quartz veins and altered rock ores near ductile shear zones. The gold-bearing quartz veins are composed of white to gray quartz associated with small amounts of pyrite and other polymetallic sulfide minerals. Wall-rock alterations include mainly beresitization, epidotization, chloritization, and carbonatization. CO2-rich inclusions are commonly seen in gold-bearing quartz veins and quartz veinlets from gold-bearing altered rocks; these include mainly one-phase carbonic (CO2 ± CH4 ± N2) inclusions and CO2–H2O inclusions with CO2/H2O volumetric ratios of 30% to ∼80%. Laser Raman analysis does not show the H2O peak in carbonic inclusions. In quartz veins, the melting temperature of solid CO2 (Tm,CO2) of carbonic inclusions has a narrow range of −59.6 to −56.8 °C. Carbonic inclusions also have CO2 partial homogenization temperatures (Th,CO2) of −28.3 to +23.7 °C, with most of the values clustering between +4.0 and +20 °C; all of these inclusions are homogenized into the liquid CO2 state. The densities range from 0.73 to 1.03 g/cm3. XCH4 of carbonic fluid inclusions ranges from 0.004 to 0.14, with most XCH4 around 0.05. In CO2–H2O fluid inclusions, Tm,CO2 values are recorded mostly at around −57.5 °C. The melting temperature of clathrate is 3.8–8.9 °C. It is suggested that the lowest trapping pressures of CO2 fluids would be 100 to ∼400 MPa, on the basis of the Th,CO2 of CO2-bearing one-phase (LCO2) inclusions and the total homogenization temperatures (Th,tot) of paragenetic CO2-bearing two-phase (LCO2–LH2O) inclusions. For altered rocks, the Tm,CO2 of the carbonic inclusions has a narrow range of −58.4 to ∼−57.0 °C, whereas the Th,CO2 varies widely (−19 to ∼+29 °C). Most carbonic inclusions and the carbonic phases in the CO2–H2O inclusions are homogenized to liquid CO2 phases, which correspond to densities of 0.70 to ∼1.00 g/cm3. Fluid inclusions in a single fluid inclusion assemblage (FIA) have narrow Tm,CO2 and Th,CO2 values, but they vary widely in different FIAs and non-FIAs, which indicates that there was a wide range of trapping pressure and temperature (P–T) conditions during the ore-forming process in late retrograde metamorphism after the metamorphism peak period. The carbonic inclusions in the Hamadi gold deposit are interpreted to have resulted from unmixing of an originally homogeneous aqueous–carbonic mixture during retrogress metamorphism caused by decreasing P–T conditions. CO2 contributed to gold mineralization by buffering the pH range and increasing the gold concentration in the fluids.

The Saidu Gold Deposit of Southern Altai, China: Mineralizing Stages and Ore-Forming Fluids Evolution

2013 ◽  
Vol 734-737 ◽  
pp. 215-218
Author(s):  
Guo Rui Zhang ◽  
Jiu Hua Xu ◽  
Li Hua Shan ◽  
Hui Zhang ◽  
Xiao Feng Wei
Keyword(s):  
Gold Deposit ◽  
Gold Mineralization ◽  
Early Stage ◽  
Shear Zones ◽  
Ductile Shear Zone ◽  
Tectonic Zone ◽  
Low Salinity ◽  
Ore Bodies ◽  
Evolution Characteristics ◽  
Homogenization Temperatures

The Saidu gold deposit is located in the northwest part of Ertix Tectonic Zone in Xinjiang. The ore bodies occur in altered mylonite zones within the Mar-kakol giant fault zone and are controlled by the ductile shear zone. The structural-metallogenic fluids of the early stage are characterized by mesothermal-hydrothermal CO2-N2-rich fluids, with homogenization temperatures of fluid inclusions being 252~408°C. The tectonic-metallogenic fluids at the middle stage are characterized by CO2-H2O fluids, with homogenization temperatures being 203~326°C. The fluids at the late stage were epithermal-mesothermal low salinity aqueous solutions, with homogenization temperatures being 120~221°C. The main gold mineralization was related to the post-orogenic extension environment, with the evolution characteristics corresponding to the evolution of shear zones.

scholarly journals Origin and Evolution of Ore-Forming Fluid and Gold-Deposition Processes at the Sanshandao Gold Deposit, Jiaodong Peninsula, Eastern China

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 189 ◽  
Author(s):  
Yazhou Liu ◽  
Liqiang Yang ◽  
Sirui Wang ◽  
Xiangdong Liu ◽  
Hao Wang ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Gold Deposit ◽  
Early Stage ◽  
Gold Deposition ◽  
Main Stage ◽  
Type Ii ◽  
Type Iii ◽  
Stage 4 ◽  
Stage 1 ◽  
Stage Stage

The Early Cretaceous Sanshandao gold deposit, the largest deposit in the Sanshandao-Cangshang goldfield, is located in the northwestern part of the Jiaodong peninsula. It is host to Mesozoic granitoids and is controlled by the north by northeast (NNE) to northeast (NE)-trending Sanshandao-Cangshang fault. Two gold mineralizations were identified in the deposit’s disseminated and stockwork veinlets and quartz–sulfide veins, which are typically enveloped by broad alteration selvages. Based on the cross-cutting relationships and mineralogical and textural characteristics, four stages have been identified for both styles of mineralization: Pyrite–quartz (stage 1), quartz–pyrite (stage 2), quartz–pyrite–base metal–sulfide (stage 3), and quartz–carbonate (stage 4), with gold mainly occurring in stages 2 and 3. Three types of fluid inclusion have been distinguished on the basis of fluid-inclusion assemblages in quartz and calcite from the four stages: Pure CO2 gas (type I), CO2–H2O inclusions (type II), and aqueous inclusions (type III). Early-stage (stage 1) quartz primary inclusions are only type II inclusions, with trapping at 280–400 °C and salinity at 0.35 wt %–10.4 wt % NaCl equivalent. The main mineralizing stages (stages 2 and 3) typically contain primary fluid-inclusion assemblages of all three types, which show similar phase transition temperatures and are trapped between 210 and 320 °C. The late stage (stage 4) quartz and calcite contain only type III aqueous inclusions with trapping temperatures of 150–230 °C. The δ34S values of the hydrothermal sulfides from the main stage range from 7.7‰ to 12.6‰ with an average of 10.15‰. The δ18O values of hydrothermal quartz mainly occur between 9.7‰ and 15.1‰ (mainly 10.7‰–12.5‰, average 12.4‰); calculated fluid δ18O values are from 0.97‰ to 10.79‰ with a median value of 5.5‰. The δDwater values calculated from hydrothermal sericite range from −67‰ to −48‰. Considering the fluid-inclusion compositions, δ18O and δD compositions of ore-forming fluids, and regional geological events, the most likely ultimate potential fluid and metal would have originated from dehydration and desulfidation of the subducting paleo-Pacific slab and the subsequent devolatilization of the enriched mantle wedge. Fluid immiscibility occurred during the main ore-forming stage due to pressure decrease from the early stage (165–200 MPa) to the main stage (90–175 MPa). Followed by the changing physical and chemical conditions, the metallic elements (including Au) in the fluid could no longer exist in the form of complexes and precipitated from the fluid. Water–rock sulfidation and pressure fluctuations, with associated fluid unmixing and other chemical changes, were the two main mechanisms of gold deposition.

scholarly journals Geology, Fluid Inclusion, and H–O–S–Pb Isotope Constraints on the Mineralization of the Xiejiagou Gold Deposit in the Jiaodong Peninsula

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-23 ◽  
Author(s):  
Peng Chai ◽  
Zeng-qian Hou ◽  
Hong-rui Zhang ◽  
Lei-lei Dong
Keyword(s):  
Fluid Inclusion ◽  
Gold Deposit ◽  
Fluid Inclusions ◽  
Gold Mineralization ◽  
Early Stage ◽  
Homogeneous System ◽  
Medium Temperature ◽  
Middle Stage ◽  
Primary Fluid ◽  
Three Stages

The Xiejiagou deposit is a representative medium-sized gold deposit in Jiaodong the Peninsula, which contains gold reserves of 37.5 t. The orebodies are hosted in the Linglong biotite granite with a zircon LA-ICP-MS U–Pb age of 160.5±1.3 Ma (N=15, MSWD=1.2) and are characterized by disseminated- or stockwork-style ores. Mineralization and alteration are structurally controlled by the NE-striking fault. Three stages of mineralization were identified with the early stage being represented by (K-feldspar) sericite quartz pyrite, the middle stage by quartz gold polymetallic sulfide, and the late stage by quartz carbonate. Ore minerals and gold mainly occurred in the middle stage. Three types of primary fluid inclusions were distinguished in the Xiejiagou deposit, including carbonic-aqueous, pure carbonic, and aqueous inclusions. The primary fluid inclusions of the three stages were mainly homogenized at temperatures of 262–386°C, 192–347°C, and 137–231°C, with salinities of 2.22–8.82, 1.02–11.60, and 1.22–7.72 wt% NaCl equivalent, respectively. These data indicate that the initial ore-forming fluids were a medium temperature, CO2-rich, and low-salinity H2O–CO2–NaCl homogeneous system, and the ore-forming system evolved from a CO2-rich mesothermal fluid into a CO2-poor fluid. Considering the fluid inclusion characteristics, H–O–S–Pb isotopes, and regional geological events, the ore-forming fluid reservoir was likely metamorphic in origin. Trapping pressures of the first two hydrothermal stages estimated from the carbonic aqueous inclusion assemblages were ~224–302 MPa and ~191–258 MPa, respectively. This suggests that the gold mineralization of the Xiejiagou gold deposit occurred at a lithostatic depth of ~7.2–9.7 km. Au(HS)2− was the most probable gold-transporting complex at the Xiejiagou deposit. Precipitation of gold was caused by a CO2 effervescence of initial auriferous fluids.

scholarly journals Hepatitis C virus enhances Rubicon expression, leading to autophagy inhibition and intracellular innate immune activation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuto Shiode ◽  
Hayato Hikita ◽  
Satoshi Tanaka ◽  
Kumiko Shirai ◽  
Akira Doi ◽  
...  
Keyword(s):  
Immune Response ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Late Stage ◽  
Early Stage ◽  
Hcv Infection ◽  
Infected Cells ◽  
The Impact ◽  
Chronic Hepatitis C Patients

Abstract Autophagy, a degradation system, works to maintain cellular homeostasis. However, as the impact of Hepatitis C virus (HCV) infection on hepatocyte autophagy and its effect on HCV replication remain unclear, we examined them. HCV infection suppressed late-stage autophagy and increased Rubicon. siRNA-mediated knockdown of Rubicon promoted autophagy in HCV-infected cells. In Huh-7 cells harbouring the HCV replicon, Rubicon knockdown downregulated the expression of type 1 interferon (IFN)-related genes and upregulated HCV replication. Rubicon overexpression or administration of bafilomycin A1 or chloroquine, an inhibitor of late-stage autophagy, suppressed autophagy and activated the type 1 IFN pathway. On the other hand, Atg7 knockout suppressed early-stage autophagy and did not activate the type 1 IFN pathway. In livers of humanized liver chimeric mice, HCV infection increased Rubicon and enhanced type 1 IFN signalling. Elimination of HCV in the mice reduced the increase in Rubicon due to HCV infection. The expression levels of Rubicon and IFN-stimulated genes in chronic hepatitis C patients were higher than those in non-B, non-C hepatitis patients. HCV infection increased Rubicon and suppressed hepatocyte autophagy, leading to activation of the intracellular immune response. Rubicon induction is involved in HCV replication via activation of the intracellular immune response.

scholarly journals Genesis of the Zhijiadi Ag-Pb-Zn Deposit, Central North China Craton: Constraints from Fluid Inclusions and Stable Isotope Data

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-23 ◽  
Author(s):  
Tao Liu ◽  
Suo-Fei Xiong ◽  
Shao-Yong Jiang ◽  
Hua-Liang Li ◽  
Qi-Zhi Chen ◽  
...  
Keyword(s):  
Fluid Inclusions ◽  
North China Craton ◽  
North China ◽  
Early Stage ◽  
Homogenization Temperature ◽  
Main Stage ◽  
Magmatic System ◽  
Hydrothermal Deposit ◽  
Homogenization Temperatures ◽  
Late Stages

The Zhijiadi Ag-Pb-Zn deposit is located in the central North China Craton. Fluid inclusions (FIs) studies indicate three types of FIs, including aqueous, aqueous-carbonic, and daughter mineral-bearing multiphase inclusions. The daughter minerals in FIs are mainly composed of marcasite, chalcopyrite, calcite, and dolomite. Microthermometric data show that the homogenization temperature and salinity of FIs decrease gradually from early to late stages. Homogenization temperatures from early to main to late stages span from 244 to 334°C, from 164 to 298°C, and from 111 to 174°C, respectively, while their salinities are 4.0–9.9 wt.% NaCl equiv., 0.5–12.7 wt.% NaCl equiv., and 0.2–8.8 wt.% NaCl equiv., respectively. Trapping pressures drop from 203–299 MPa (the early stage) to 32–158 MPa (the main stage). The dropping of pressure and temperature and mixing and/or dilution of ore-forming fluids result in the formation of ore deposit. Combined with C-O-S-Pb isotopic compositions, the initial ore-forming fluids and materials were likely derived from a magmatic system. As a whole, we proposed that this deposit belongs to medium-low temperature hydrothermal deposit related to volcanic and subvolcanic magmatism strictly controlled by the fault zones.

scholarly journals Genesis of the Koka Gold Deposit in Northwest Eritrea, NE Africa: Constraints from Fluid Inclusions and C-H-O-S Isotopes

2019 ◽  
Author(s):  
Kai Zhao ◽  
Huazhou Yao ◽  
Jianxiong Wang ◽  
Ghebsha Fitwi Ghebretnsae ◽  
Wenshuai Xiang ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Meteoric Water ◽  
Gold Mineralization ◽  
Early Stage ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Quartz Veins ◽  
Three Phase ◽  
Igneous Origin ◽  
Ne Africa

The Koka gold deposit is located in the Elababu shear zone between the Nakfa terrane and the Adobha Abiy terrane, NW Eritrea. Based on the paragenetic study two main stages of gold mineralization were identified in the Koka gold deposit: 1) an early stage of pyrite-chalcopyrite-sphalerite-galena-gold-quartz vein; and 2) a second stage of pyrite-quartz veins. NaCl-aqueous inclusions, CO2-rich inclusions, and three-phase CO2-H2O inclusions occur in the quartz veins at Koka. The ore-bearing quartz veins formed at 268℃, from NaCl-CO2-H2O(-CH4) fluids averaging 5 wt% NaCl eq. The ore-forming mechanisms include fluid immiscibility during stage I, and mixing with meteoric water during stage II. Oxygen, hydrogen and carbon isotopes suggest that the ore-forming fluids originated as mixtures of metamorphic water, meteoric water and magmatic water, whereas sulfur isotope suggest an igneous origin. Features of geology and ore-forming fluid at Koka deposit are similar to those of orogenic gold deposits, suggesting the Koka deposit might be an orogenic gold deposit related to granite.

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