Papers by Keyword: Fluid Inclusion

Abstract: The occurrence and homogenization temperature of fluid inclusions as well as salinity measurement and Laser Raman test, etc. from Tumengela Formation of Upper Triassic in Woruo Mountain area of North Qiangtang Basin are analyzed in this paper. Which indicating that the inclusions of the study area are mostly in small size with rules and developed in strips or groups. The GOI of the inclusions is especially high, and the homogenization temperature shows two peak values. Besides, the organic inclusions fluorescent display is extremely weak or even nothing. It is believed by combining of the analysis of the host mineral diagenesis stages and salinity of brine in the inclusions that there existed two large scale processes of hydrocarbon generation and migration. Namely, early one is in a small scale with oil migration, later one is in a large scale with gas migration.

Abstract: In this paper we use new field data, fluid inclummsions, and table isotopes (O, H, and S) to refine the roles of the hydrothermal evolution, evaluate changes in the hydrothermal fluids of Duobaoshan porphyry Cu (Mo) deposit and Sankuanggou skarn Fe-Cu deposit. Four ore-forming stages are recognized at The Duobaoshan porphyry Cu (Mo) deposit. Fluid inclusions are abundant in quartz of various stages. Estimated trapping pressures for stage I, II, III are 110-160MPa, 58-80MPa, and 8-17MPa, corresponding trapping temperatures are 375-650°C, 310-350°C, 210-290°C. The δD and δ¹⁸O values of fluids indicate a evolution process from magmtic hydrothermal fluid to a mixing magmtic and meteoric fluid. The δ³⁴S values of sulfides mainly suggest predominantly source of deep magma chamber.

Abstract: The Huajian gold deposit is located in the metallogenic belt of the northern part of the North China block. This deposit's ore bodies are mainly hosted in metamorphosed Neoarchean and Mesoproterozoic sedimentary rocks, of which Mesozoic volcano-intrusive complexes are closely associated with the Gold mineralization. The FIs of the Huajian deposit are primarily aqueous FIs with minor gas FIs. The pure gas or liquid FIs are very few. The ore-forming fluids were characterised by moderate–low temperature, low salinity and high oxygen fugacity and belonged to an H₂O–NaCl ± CO₂ system. The FIs in quartz veins primarily developed in temperature intervals of 202–380°C, 191–407°C and 170–307°C., corresponding to salinities of 3.85wt.% to 11.23 wt.%, 3.69wt.% to 10.99 wt.% and 2.06wt.% to 17 wt.% NaCl eq.., respectively. The trapping pressures of the FIs from high temperature fluids in the quartz veins are 10-90 MPa, corresponding to depths of 1.0–10 km, assuming a density of the overlying rocks of 0.54 g/cm3–0.98 g/cm3. Multiple stages of phase separation or immiscibility of ore-forming fluid was critical for the formation of the Huajian deposit.

Abstract: Bangpu molybdenum-copper polymetallic deposit is located in the eastern section of the Gangdese Porphyry Copper Belt of Tibet. It is a typical large porphyry molybdenum copper polymetallic deposit. The isotope study of fluid inclusions H and O in the quartz (calcite) of various mineralization stages shows that, the ore-forming fluid comes mainly from meteoric hydrothermal caused by atmospheric precipitation, which has consistency with ore-forming fluid sources of Gangdese Porphyry Copper Belt. The Mo-Cu phase with low δD value (-140.5 ~ -104.0 ) suggests a large-scale magmatic degassing. The alteration and mineralization have been caused precisely by the degassing, and the obvious O isotope drift occurred being accompanied by alteration-mineralization, so that the fluid has a low δ¹⁸O (vary from 5.50 to 9.0 ). The statistical research indicates that, the massive magmatic degassing occurred in Gangdese Porphyry Copper Belt, and was gradually increased from east to west, suggesting the direct impact of the magmatic degassing on the formation of the porphyry copper-gold deposit and molybdenum copper deposit: the stronger the magmatic degassing, the more easily to form the molybdenum-based porphyry deposit, otherwise it will be formed the deposits dominated by Cu and Au.

Abstract: In the thesis, we studied fluid inclusions in minerals and mineralization epochs of Luziyuan Pb-Zn deposits in eastern of Zhenkang Yunnan province. 240 available data have been obtined by observing characteristics of fluid inclusions in sphalerite, quartz, fluorite, calcite under microscope and selecting 284 primary inclusions and secondary inclusions thermometry. Various mineralization epochs homogenization temperature, freezing temperatures, salinity frequency histogram showed a bimodal distribution mode. The fluid inclusions in sphalerite have a greatly important,it is ore-forming fluids. Its homogenization temperature distributed in 240 to 270°C (medium temperature) and 187 to 220°C (low temperature) within the range of two, (W NaCl) salinity is 5.0% to 10.6%. According to the homogenization temperature and salinity, it can be deduced Luziyuan mineralization fluids density of 0.82 to 0.96 (gcm^-3). Draw the deposits are mainly two hydrothermal mineralization, a hydrothermal in medium temperature, another period of low and medium temperature. The two ore-forming fluids are medium salinity and medium-density.

Abstract: Fluid inclusions, carbon and oxygen isotopic compositions were discussed to understanding the ore-forming fluid system of Anqing Cu-Fe deposit. Homogeneous temperatures of fluid inclusions ranged from 124°C to 570°C, δ¹³C_PDB values of the gangue minerals ranged from-3.3 to-0.9, and δ¹⁸O values ranged from 9.4 to 10.7, respectively. The results reveal that the primary ore-forming fluid was magmatic hydrothermal fluid characterized by high temperature, the boiling and mixing of fluids occurred in the main mineralization stage, the magmatic water was dominant in the ore-forming process, the physicochemical condition changes of the fluid system led to the formation of skarn and the deposition of the ore minerals. The ore-forming materials were mainly derived from magma, partly provided by sedimentary strata.

Abstract: This paper analyzes the fluid inclusions, micro-thermometry, the pressure, salinity and pH of ore-forming solution, and isotopes of H and O, C and O of the Dahongshan copper deposit in Yunnan Province. The result shows that these inclusions are dominated by liquids (L_H2O), gases and liquids (L_H2O+V_H2O), and daughter mineral-bearing (L_H2O+V_H2O+S_NaCl) three-phase ones and the liquid inclusion accounts for about 50%, and the liquid composition mainly include Na⁺,K⁺,F^-,Cl^-. Homogenization temperatures at the early stage vary from 290°C to 330°C, with the peak value around 350°C, while at the late stage the figures vary from 160°C to 250°C, with the peak value 250°C. The general salinity ranges from 16.0 wt% to 35.9wt%, and the maximum reaches 45wt%. The value of δ¹⁸O_H2O and δD in the mineral inclusion ranges from-1.15% to 6.61% and from-58% to-78% respectively. These isotopic data imply that the ore-forming fluids were mainly derived from the magmatic water, the metamorphic water and the meteoric water.

Abstract: 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.

Abstract: Palaeopressures of the Jurassic formation in the hinterland of the Junggar Basin were reconstructed at different geological time with the method of fluid inclusion thermodynamic modeling. The results indicate that, the generation of overpressure in the east is earlier than that in the west. The overpressure center was first located in the east part of the Changji depression, and then migrated northwestward. The evolution of the formation pressure displays a trend of pressure decrease as a whole, and this trend is composed of three cycles of pressure down and up in block I and IV, but just one in block III and two in block II. Block III is a potential prospective area for hydrocarbon accumulation due to the long-term pressure releasing, and the last cycle which resulted in current formation pressure status in all of the four blocks suggests that the later gas charging had an obvious effect on the pressure accumulation.

Abstract: Comprehensive application of fluid inclusions data from the Upper Triassic reservoir of Chuanxi foreland basin in China, integrated with burial history and thermal evolution, indicates that there are four episodes of hydrocarbon charge during geologic history: early thermo-genetic oil stage, middle thermo-genetic oil stage, late thermo-genetic gas stage, structural adjustment charge stage. In every phrase of charge, four types of fractures origin from inflexible compaction, acid dissolution, breaking by abnormal pressure and tectonic deformation played a essential role in migration and accumulation of hydrocabon in the Upper Triassic reservoir of Chuanxi foreland basin.