Geological and Fluid Inclusion Constraints on Gold Deposition Processes of the Dayingezhuang Gold Deposit, Jiaodong Peninsula, China

2019 ◽  
Vol 93 (4) ◽  
pp. 955-971 ◽  
Author(s):  
Peng CHAI ◽  
Zhiyu ZHANG ◽  
Zengqian HOU
Keyword(s):  
Fluid Inclusion ◽  
Gold Deposit ◽  
Gold Deposition ◽  
Jiaodong Peninsula ◽  
Deposition Processes

Ore geology, fluid inclusion, and stable isotope constraints on the origin of the Damoqujia gold deposit, Jiaodong Peninsula, China

2020 ◽  
Vol 57 (12) ◽  
pp. 1428-1446
Author(s):  
Peng Chai ◽  
Hong-rui Zhang ◽  
Zeng-qian Hou ◽  
Zhi-yu Zhang ◽  
Lei-lei Dong
Keyword(s):  
Fluid Inclusion ◽  
Gold Deposit ◽  
Eastern China ◽  
Homogeneous System ◽  
Gold Deposition ◽  
Medium Temperature ◽  
Rock Interaction ◽  
Jiaodong Peninsula ◽  
Primary Fluid ◽  
Gold Producer

The Damoqujia gold deposit within the Zhaoping Fault Zone on Jiaodong Peninsula in eastern China is hosted primarily by Mesozoic granitoids and contains >60 t of gold, making it an important gold producer. Three mineralization stages are distinguished (early, middle, and late): (K-feldspar)–sericite–quartz–pyrite, quartz – gold – polymetallic sulfides, and quartz–carbonate. Gold deposition occurred mainly in the middle stage. The primary fluid inclusions of three stages are mainly homogenized at temperatures of 236–389, 191–346, and 104–251 °C, with salinities of 2.96–11.33, 1.39–17.28, and 0.53–11.48 wt.% NaCl equivalent, respectively. Fluid inclusion studies indicate that the metallogenic system evolved from CO2-rich mesothermal homogeneous fluids to CO2-poor aqueous fluids due to inputs of meteoric waters. The gold was carried as a bisulfide complex in the ore-forming fluids. Precipitation of gold was caused by a combination of fluid immiscibility and water–rock interaction. Studies of the fluid inclusion characteristics (medium temperature, CO2-rich, and low salinity H2O–CO2–NaCl homogeneous system), hydrogen and oxygen isotopes ([Formula: see text] = –1.0‰ to 7.6‰, δD = –109‰ to –77‰), sulfur values ([Formula: see text] = 4.5‰ to 8.5‰), and regional geological events show that the ore-forming fluids reservoir was likely metamorphic in origin. Based on the immiscibility of fluid inclusion assemblages, the estimated depth and pressure of trapping are 8.3–10.2 km and 83–276 MPa, respectively, corresponding to the depth and pressure of mineralization.

Origin and evolution of ore fluid, and gold-deposition processes at the giant Taishang gold deposit, Jiaodong Peninsula, eastern China

2016 ◽  
Vol 72 ◽  
pp. 585-602 ◽  
Author(s):  
Li-Qiang Yang ◽  
Jun Deng ◽  
Lin-Nan Guo ◽  
Zhong-Liang Wang ◽  
Xiu-Zhang Li ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Eastern China ◽  
Gold Deposition ◽  
Origin And Evolution ◽  
Jiaodong Peninsula ◽  
Deposition Processes

Fluid immiscibility and gold deposition in the Xincheng deposit, Jiaodong Peninsula, China: A fluid inclusion study

2015 ◽  
Vol 65 ◽  
pp. 701-717 ◽  
Author(s):  
Zhong-Liang Wang ◽  
Li-Qiang Yang ◽  
Lin-Nan Guo ◽  
Erin Marsh ◽  
Jian-Ping Wang ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Fluid Inclusion Study ◽  
Gold Deposition ◽  
Fluid Immiscibility ◽  
Jiaodong Peninsula ◽  
Inclusion Study

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.

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.

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