1 metallogenic geological background
The strata in this area are mainly Triassic Bayankala Group and a small number of Lower Permian Buqingshan Group. Bayankala Group is a shallow-semi-deep marine argillaceous flysch formation, which is composed of sandstone-mudstone (metamorphic slate)-sandstone from bottom to top, reflecting the sedimentary cycle from transgression to regression. The Lower Permian Buqingshan Group is NW-trending and obviously controlled by faults. The lithology is mainly intermediate-basic volcanic rocks, clastic rocks and carbonate rocks.
The regional structure is dominated by Indosinian deformation, with faults and folds developed. Folds are generally large-scale Zalinghu compound anticlines, the core of which is composed of Permian horst-like fault blocks, and the Triassic strata on both wings develop complex plastic fold structures. The northern part of the mining area is a Gande-Maduo deep fault, and there are a series of parallel secondary faults in NWW direction and a group of NE-trending translational faults in Dachang area. NWW fault is the main ore-controlling structure in this area. The NE-trending fault passes through strata and NWW-trending structures.
Magmatic activity is relatively weak. The intrusive rocks are mainly Indosinian intrusive rocks, followed by Yanshanian intrusive rocks. Lithology mainly includes quartz diorite, biotite syenite diorite and porphyritic biotite adamellite, which occur in beads, and there is no rock intrusion in the mining area. The extrusive rocks are marine volcanic deposits in the early Permian strata, and the volcanic activities are mostly intermittent fissure eruption, and the lithology is andesite, basalt and pyroclastic rocks.
2 Geological characteristics of the deposit
Dachang gold deposit is located in the northern Bayan Kara orogenic belt of Songpan-Ganzi Indosinian fold system. The exposed strata in the mining area are mainly sandstone and slate interbeds of Triassic Bayankala Group (TBy2), which are ore-bearing strata in the mining area. Sandstone and slate are rhythmically interbedded, showing typical sedimentary characteristics of turbidite, in which carbonaceous slate contains higher gold. The Permian Marzheng Formation (P 1m) of Buqingshan Group is distributed between the Gande-Maduo fault zone in the northeast corner of the mining area. The Gande-Maduo deep fault is the largest fault in the mining area. Affected by it, secondary pinnate faults and folds are developed in the strata on both sides. The fault strikes NW, inclines to NE, and the dip angle is about 60. It is a brittle-ductile reverse fault with a crushing bandwidth of 20 ~ 200 m. The development of silicification and pyritization in the fracture zone provides a favorable channel for ore-bearing hydrothermal solution. Influenced by the Gande-Maduo deep fault, the secondary faults and interlayer fracture zones in sandstone and slate interlayers of the Lower Middle Triassic Bayankala Formation in the fault zone are well developed, showing parallel feather shape, with the strike of 1 10 ~ 130, and the dip angle is 40 ~ 60. The bandwidth of these ore-bearing faults and alterations is generally 1 ~ 20m, and most of them are longer than 1km. The strike and dip angle of fault plane are gentle waves, and various structural rocks (such as porphyry and mylonite) often develop reticulate, veinlets and lenticular time veins. There is no exposed rock mass in the mining area, but the mineralization in the area is closely related to magmatic intrusion. Geophysical data show that there are intermediate-acid concealed rock masses in the depth of Dachang gold mining area.
2. 1 ore body characteristics
Up to now, 35 gold ore bodies have been delineated in Dachang Gold Mine, which are mainly distributed in the range of 3km wide and 5km long to the north of Dachang River (Figure 1). The ore body occurs in the southwest side (footwall) of Gande-Maduo main fault. Gold ore bodies are strictly controlled by structural fracture alteration zone, and their scale is related to fracture zone. If the fracture zone is large and the alteration is strong, the gold ore body is large in scale and high in grade. On the contrary, the scale is small and the grade is low. The ore-controlling fractured alteration zone is parallel to the main fault zone and is a secondary fault derived from the main fault zone. The distribution of gold ore bodies seems to be equidistant from north to south, with a spacing of 400 ~ 600 m. Most of the ore bodies are banded, layered, pod-shaped and lenticular, with wavy bending, expansion and contraction, branching, compounding and bifurcation along the strike, and the change law along the dip is not clear.
Figure 1 Geological Schematic Diagram of Dachang Gold Mine
(According to the revision of Qinghai Geological Survey Institute in 2002)
Q- four yuan; Tby 2—— Gray-green sandstone partition of Triassic Bayankala Group subgroup. 1- gold ore body
The length of ore bodies is 80 ~ 3240 meters, and the ore bodies with the length > 1000 meters account for more than half of the total ore bodies. The ore body is lenticular in strike, and it bends, expands, contracts and forks in waves along strike. The thickness of the surface layer is generally 1.4 ~ 4.57m, the maximum is 15.64m, the gold grade is 0.53x10-6 ~ 24.9x10-6, and the average grade is 7.5x10.
2.2 Ore characteristics
According to the mineral assemblage, occurrence conditions and metallogenic characteristics, the ore types in this area are divided into cataclastic sulfide altered rock type and gold-bearing iron ore quartz vein type.
The cataclastic sulfide altered rock type is the main ore type in this area and widely distributed. All ores are altered by silicification, sulfidation, sericitization and argillization to varying degrees. Metal minerals are mainly pyrite, arsenopyrite and natural gold. Pyrite is irregular and irregular, with a particle size of 0. 1 ~ 1 mm and a content of 3% ~ 5%. The arsenopyrite is needle-shaped, with a particle size of 1 ~ 3 mm and a content of 5%. Non-metallic minerals include feldspar, quartz, chlorite, sericite and slate debris.
Shi Ying vein type gold-bearing iron ore is a secondary ore type. The ore is veinlets, reticulated veins or massive. The timely content in the ore is 90% ~ 95%, and the pyrite content is generally 5% ~ 10%, mostly in the form of irregular particles, some in the form of cubes, and the particle size is 0.5~2mm. Pyrite has been oxidized into limonite in the oxidation zone, and bright gold is occasionally seen in this ore.
2.3 Occurrence state of gold
The metal minerals in the ore mainly include native gold, pyrite, arsenopyrite, stibnite, chalcopyrite, galena and sphalerite. The content of arsenopyrite is 5% ~ 15%, pyrite is 2% ~ 20%, stibnite is 1% ~ 4% (only on the surface), and there are traces of chalcopyrite, galena and sphalerite. Oxidized minerals include limonite, malachite and antimony. Nonmetallic minerals include quartz, feldspar, calcite, slate fragments, clay and sericite.
Multielement chemical analysis results: Au is 0.1×10-6 ~10-6, with an average of 6.3× 10-6 and Sb is 0.01%.
The occurrence state of gold in ore is complex. In Shi Ying vein type gold ore containing gold ore, native gold (particle size 0.74~2mm) accounts for about 265,438 0%, particle size less than 0.74 ~ 2mm and invisible gold accounts for about 79%. A large amount of natural gold was found in the mid-ray identification of stibnite in Yingshi vein. A small amount of natural gold was also found in the artificial heavy sand identification of cataclastic sulfide altered rock type gold deposits, with a particle size of 0.0 1 ~ 0.2 mm, which was dendritic, flaky, granular and membranous. The analysis of gold content in single mineral shows that pyrite contains 40× 10-6 ~ 80× 10-6, arsenopyrite contains 177× 10-6 and stibnite contains 2×10-6. The gold grade of artificial heavy sand is 1 1× 10-6. The content of natural gold is 2.65× 10-6, accounting for 2 1% of the total gold content, indicating that a large amount of gold in gold ores exists in fine and ultra-fine (particle size < < 0.02mm) forms in ores, mineral fractures and crystal lattices, and gold is closely related to pyrite and arsenopyrite.
According to this analysis, the occurrence forms of gold are not only natural gold monomer (visible gold), but also fine inclusions (such as inclusion gold, interstitial gold and fissure gold). Because the content of gold is closely related to pyrite, arsenopyrite and stibnite, the possibility of lattice gold cannot be ruled out. Because the ore contains a variety of argillaceous and clay, it is speculated that a small amount of colloidal particles adsorb gold.
2.4 surrounding rock alteration
The surrounding rock alteration in the mining area is developed, and its scale and strength depend on the structural scale, nature and rock fragmentation. The main changes are silicification, sericitization and sulfidation, and some are kaolin and carbonation. Among them, pyritization, sericitization and silicification are most closely related to gold and antimony mineralization. From the center of the ore body to the outside, the alteration shows silicification, sulfide-sericitization, carbonation and kaolin in turn.
3 genesis of ore deposit
3. 1 Geochemical characteristics of the deposit
See table 1 for multi-element analysis of ore chemistry.
According to the table 1, the ore-forming elements in the mining area are characterized by high contents of Au, S, As and Sb and low contents of Ag, Cu, Pb and Zn. W(Au)/w(Ag)≈ 1 contains a small amount of organic carbon, which may be involved in mineralization.
By analyzing the composition of pyrite and arsenopyrite by SEM (Table 2), it is found that vein pyrite and disseminated pyrite contain 4.20% and 4.30% Au, 65,438+0.98% and 2.24% Pt respectively, and arsenopyrite contains 2.43% Au and 65,438+0.35% Pt respectively.
Table 1 results of multi-element analysis of mineral chemistry w(B)/%
Note: The data were tested by Qinghai Institute of Rock and Mineral Testing and Application in 2004. According to Zhao Junwei, 2007.
Table 2 SEM composition analysis of pyrite and arsenopyrite w(B)/%
Note: The data were tested by Qinghai Institute of Rock and Mineral Testing and Application in 2004. According to Zhao Junwei, 2007.
3.2 Characteristics of Fluid Inclusions
Through microscopic observation of five thermometric slices (Zhao et al., 2005), it is found that calcite and calcite are rich in fluid inclusions, and they are all primary inclusions related to mineralization. These inclusions appear in groups, with similar gas-liquid ratio, uniform temperature and consistent internal composition, and the main components are CO2 and H2O.
Types and characteristics of fluid inclusions
According to the physical phase and chemical composition of inclusions at room temperature, the primary inclusions in the samples can be divided into three types: type I (gas-liquid two-phase inclusions), type II (three-phase inclusions containing CO2) and type III (CO2-rich inclusions) (Zhao et al., 2005). Type I is a gas-liquid two-phase inclusion, namely NaCl-H2O type, accounting for about 77% of the total inclusions. It is mainly gas-liquid two-phase, that is, it is composed of (H2O+NaCl) (liquid phase) and H2O (gas phase), with the liquid phase as the main component. Generally, the gas phase is 5% ~ 30%, mostly 10% ~ 15%. The long axis of inclusions is generally 6 ~ 40μ m, and most of them are between10 ~15μ m. The inclusions are oval, rectangular and irregular, and a few are regular negative crystal forms and incomplete negative crystal forms. Although the results of laser Raman spectrum analysis show that the gas phase of this kind of inclusions contains CO2, due to the small volume of the gas phase, CO2 phase has not been observed at room temperature and low temperature, and a very small amount of CO2 is not enough to change the basic characteristics of NaClH2O in the inclusions. This kind of inclusion is the most widely developed and is the main type of inclusion in Dachang gold deposit.
Type ⅱ is a three-phase inclusion containing CO2, namely CO2-H2O-NaCl type, accounting for about 13% of the total inclusion. It has three phases at room temperature, consisting of CO2 (gas phase) +CO2 (liquid phase) +(H2O+NaCl) (liquid phase), and the gas phase CO2 often shakes. Although a few inclusions present CO2 and salt solution at room temperature, CO2 gas phase appears after cooling to about-10℃. The φ(CO2) (volume fraction) of CO2 phase is 10% ~ 50%, and most of it is 30% ~ 40%. The shape of inclusions is oval and irregular strip, and the long axis is generally 8 ~ 40μ m, mostly between12 ~15μ m. This kind of inclusions is well developed, but its distribution is uneven.
Type ⅲ is CO2-rich inclusions, accounting for 10% of the total inclusions. Almost all of them are filled with CO2, and the inclusions are negative crystal, oval and irregular. The main axis is generally 7 ~15μ m, and most of the inclusions are <10μ m. The gas-liquid volume ratio of CO2-rich inclusions is generally 75% ~ 95%, and their distribution characteristics are very similar to those of CO2-containing three-phase inclusions, which are often associated with them. The inclusions rich in CO2 are sometimes two-phase at room temperature, but three-phase after cooling. The overall color of inclusions is dark and the center is transparent. In addition, there is a small amount of pure CO2 inclusions, mostly gas-liquid two-phase at room temperature, a small amount of single gas phase or liquid phase, and homogeneous gas phase.
3.2.2 Microscopic temperature measurement results
The temperature of 55 inclusions in 5 samples was measured by gas-liquid two-phase fluid inclusions (type ⅰ). The tm of gas-liquid two-phase inclusions is -6.2 ~- 1.2℃, with an average value of -3.6℃, concentrated at -6 ~-2℃. Th of gas-liquid two-phase inclusions is 152.2 ~ 3 14.7℃, with an average of 2 1 1℃, which is concentrated in 170 ~ 270℃ (Figure 2).
Fig. 2 Histogram of temperature measurement data of Dachang gold deposit
(According to Zhao et al., 2005)
Using Hall et al.' s salinity formula (1988), the corresponding salinity value of gas-liquid two-phase inclusions can be obtained. The results show that the salinity of gas-liquid two-phase inclusions in Dachang gold mine area is 2. 1% ~ 9.5%, with an average value of 5.83, and the main variation range is 5 ~ 8 (Figure 3).
Fig. 3 Homogeneous temperature-salinity diagram of fluid inclusions
(According to Zhao et al., 2005)
On the basis of obtaining the homogeneous temperature and salinity of this kind of inclusions, the fluid density is calculated by using the empirical formula of Liu Bin et al. (1987): (A, B and C are dimensionless parameters). The calculation results show that the fluid density in Dachang gold mine area ranges from 0.78 to 0.95 g/cm3, with an average value of 0.89 g/cm3.
According to the homogeneous temperature and fluid salinity of fluid inclusions, Shao Jielian (1988) calculated the fluid pressure with the empirical formula of p = p0th/t0 (where p0 = 2 19+2620w, t0 = 374+920w), and obtained the fluid pressure of the corresponding inclusions. The results show that the fluid pressure of gas-liquid two-phase inclusions in Dachang mining area is 465,438+0× 65,438+006 ~ 87× 65,438+006 Pa, with an average of 57× 65,438+006 Pa, mainly between 45× 65,438+006 Pa.
Three-phase inclusions containing CO2 (type Ⅱ) were measured, and the tm(CO2) was -57.2 ~-56.9℃. Th(CO2) of these inclusions is 23.6 ~ 29.6℃, with an average of 26.3℃. Th(cla) is 5.0 ~ 8.65438 0℃, with an average of 6.0℃. Th is 2 18.2 ~ 304.5℃, with an average of 254.3℃. Some inclusions of this type break before they are uniform, and a completely uniform temperature cannot be obtained.
Collins( 1979) thinks that there is a certain functional relationship between the melting temperature of the CO2 inclusion compound and the salinity of the aqueous solution, and the salinity of the aqueous solution of the inclusion compound can be indirectly obtained by measuring the melting temperature of the inclusion compound. According to Bozzo et al.' s salinity calculation formula (1973), it is calculated that the salinity of this kind of inclusion aqueous solution is 3.8% ~ 9.0%, which is concentrated in 8.3% ~ 9.0% (Figure 3).
According to the completely uniform temperature of the three-phase inclusions containing CO2 and the salinity of the aqueous solution, the fluid density can be calculated by using the empirical formula of Liu Bin et al. (1987). The fluid density in Dachang gold mine area is mainly distributed between 0.74 and 0.89 g/cm3, with an average value of 0.85 g/cm3. According to the P-t phase diagram of the H2O-CO2-NaCl system of Brown et al. (1989), the fluid pressure ranges from 57×106 to 82×106 Pa, with an average of 72× 106Pa.
CO2-rich inclusions (type Ⅲ). Zhao et al. (2005) measured the temperatures of eight inclusions in two samples, and found that the initial melting temperature tm(CO2) of such inclusions was -57.3 ~-56.8℃, which was slightly lower than the triple point of CO2 -56.6℃, indicating that CO2 in the inclusions was pure. The partial homogenization temperature th(CO2) is 65438 09.2 ~ 24.6℃, with an average of 265438 0.7℃. The disappearance temperature th(cla) of the inclusion complex is 5.5 ~ 9.9℃, with an average of 6.065438 0℃. This inclusion is homogeneous in the gas phase, and its Th is 273.0 ~ 323.5℃, with an average of 295.4℃. Pure CO2 inclusions cannot obtain a completely consistent temperature (Figure 2).
According to the formula of Bozzo et al. (1973), the salinity of CO2-rich inclusions is 0.2% ~ 8.3%, with an average of 4.5%. The fluid density of CO2-rich (or pure) inclusions in Dachang gold mine area was calculated by the empirical formula of Liu Bin et al. (1987), and the average value was 0.73 g/cm3. This value is put into the P-x phase diagram of H _ 2O-CO _ 2 system of Roedder et al. (1980), and the fluid pressure is 40.
3.2.3 Composition of fluid inclusions
The gas phase composition of type I inclusions is mainly (Zhao et al., 2005), and its relative content of X () is generally 92. 12% ~ 97.57%. Followed by CO2, x(CO2) is generally 0.61%~ 6.87%; It also contains a small amount of CH4, C2H2, H2S, CO, N2 and H2. The main component in the liquid phase is H2O, and x(H2O) is 95.3 1% ~ 99.36%. X(CO2) is generally 0.1%~1.29%; In addition, it also contains a small amount of CH4 and CO, and H2S, N2, C2H2, C2H6, C3H8 and C6H6 are found in some inclusions. The anion component is mainly Cl-.
The gas phase of type ⅱ and type ⅲ inclusions is mainly CO2, and the x(CO2) is 39.47% ~ 84.3%. H2O followed by X (X(H2O)8.29% ~ 29.04%；%; The contents of N2 and CO are relatively high, and the x(B) is 2.7% ~1.1%and 2.08% ~ 9.94% respectively. Individual inclusions contain a small amount of CH4, C2H4, C2H6, C3H8 and C6H6, and their x(B) is less than 3%. The liquid phase composition of type ⅱ inclusions is mainly H2O, followed by CO2 and N2, and the contents of CO, CH4, C2H2 and C2H6 are relatively low.
Generally speaking, ore-forming fluid is rich in CO2, belonging to NaCl-H2O-CO2 system type. In addition, it also contains a small amount of CO, H2S, CH4, N2, H2 and a small amount of organic components such as C2H2, C2H4, C2H6, C3H8, C6H6, indicating that it is a salt solution containing organic matter. The existence of organic components is consistent with the high carbon content of the surrounding rock of Dachang gold deposit. The existence of organic matter in hydrothermal solution enhances the ability of hydrothermal solution to activate and migrate metal ore-forming elements in rocks (Lu et al., 2000), which plays an important role in the mineralization of Dachang gold deposit.
3.3 Ore-controlling factors
3.3. 1 Formation ore-controlling factors
The discovered gold deposits and gold spots in Dachang area all occur in sandstone of Triassic Bayankala Group. According to rock statistics, the highest gold content of mylonite is 33.63× 10-9, and the coefficient of variation is 2 10%. Siltstone 12.07× 10-9, with a coefficient of variation of 400%; Slate is 9.46× 10-9, and the coefficient of variation is 450%. Sandstone is 3.5× 10-9, and the coefficient of variation is 180%. Slate and siltstone have the largest coefficient of variation, and it is preliminarily considered that the ore-forming materials in this area mainly come from Triassic sandstone strata which are widely distributed.
To sum up, from Late Triassic to Early Jurassic, the ocean/basin subducted northward and gradually closed from east to west, forming Bayankala orogenic belt. This subduction-collision increased the geothermal temperature and provided a heat source for the formation of thermal fluid, which not only led to the low greenschist facies metamorphism and folding of Triassic flysch sedimentary rocks, but also was strongly deformed by thrust. At the same time, large-scale thrust, strike-slip fault, ductile-brittle shear zone and its supporting low-level structural system are formed, and argillaceous and silty slate interbedded with sandstone in the stratum, forming favorable ore-hosting structure and barrier.
3.3.2 Structural ore-controlling factors
The Gande-Maduo deep fault in the north of the mining area is one of the NWW-trending regional faults formed during the Indosinian movement. In the early stage, it showed ductile shear, and then it showed strong thrust and strike-slip, which was related to the northward subduction of Bayankala basin (ductile shear) and then the oblique collision of East Kunlun block (formation of converted compression zone). The above process is realized in the process of regional fold uplift, that is, the evolution process of structure from deep ductile shear to shallow brittle fracture, which is consistent with regional orogeny uplift. Dachang mining area has developed a series of NW-trending dip folds, which are composed of strongly schistose slate and strongly fractured sandstone (Bayankala Group of Lower Triassic), and bedding is strongly replaced by foliation. Thick lenticular gold (antimony) ore bodies occur in the fracture-fracture system of the axis of nearly inclined annular fold. The ore-hosting structure of this deposit is the supporting structure of the oblique (dextral) thrust fault of Gande-Maduo fault in Indosinian period. Based on this, it is considered that Dachang gold deposit is the product of the combination of Bayankala structural unit and East Kunlun block. The ore-controlling structure of the deposit was formed in the late stage of this process (oblique collision period). Zhang Dequan used sericite 40Ar-39Ar method to date the altered and fractured gold-antimony ore in Dachang deposit, and the result was (218.6 3.2) Ma, which proved the rationality of this reasoning.
Dachang Gold Mine is controlled by the east-west-northeast large shear zone in Triassic flysch turbidite series (low greenschist facies metamorphism), and the brittle faults in the large shear zone are related to specific mineralized bodies. The reason for ore control in shear zone may be that gold deposits in shear zone usually have a gradual enrichment process. In the process of mylonitization, shearing can make low-content gold in the original rock migrate, forming disseminated and veinlet disseminated gold deposits in mylonite. However, in the brittle deformation stage superimposed on the mylonite stage, the development of cleavage, schist and fracture leads to the increase of rock porosity, which is beneficial to the hydrothermal activity and mineral precipitation in the later stage. Therefore, vein-like and altered rock-type gold-rich deposits can be formed at this stage, and the spatial occurrence position of gold-rich deposits is controlled by shear zone. The natural type of ore is broken altered rock type gold deposit, and its mineral composition includes pyrite, arsenopyrite, stibnite and natural gold. Non-metallic minerals include quartz, feldspar and clay minerals. The deformation fabric in the ore is abnormally developed, all of which are fracture or mylonite structures, showing strong ductile-brittle deformation characteristics. Seasonal minerals are rich in fluid inclusions, mainly liquid-rich inclusions and gas-liquid multiphase inclusions, and a small amount of gas-rich inclusions.
The above characteristics reflect that Dachang Gold Mine is driven by strong structure, forming huge fluid circulation, leading to large-scale structural deformation and hydrothermal filling mineralization alteration. This type has the characteristics of concentrated zonal distribution, which is directly related to the acid magmatic activity during orogeny. Generally speaking, it is not selective to strata, and mostly occurs in altered zones or altered rock masses with high background and broken rock strata. It is strictly controlled by nearly NW-trending faults and a series of parallel NW-trending and NWW ductile shear zones. Ore body,
In addition, the ore body was reformed by the later fold and deformed with the fold deformation. Some "nose-shaped" small folds with NW tendency are often formed along the strike of main ore bodies in central and western mining areas, and it can be inferred that the formation time of ore bodies is after regional metamorphism and before fold deformation.
To sum up, the ore body of Dachang Gold Mine was located in Indosinian orogenic period (Late Triassic), and it was mainly controlled by deep fault (or collision zone), large shear zone and brittle fault in North Bayankala from region and ore field to deposit (body).
3.3.3 Metallogenic mechanism
Dachang deposit is the product of gold-antimony mineralization in the northern margin of convergence plate in the late Indosinian movement. Collisions and the resulting geothermal warming drive metamorphic water (formation metamorphism and dehydration) to migrate along large faults, continuously extracting minerals, including carbon, sulfur, gold, antimony and arsenic. In the process of regional uplift, there is continuous infiltration of atmospheric precipitation, thus forming CO2-NaCl-H2O fluid rich in ore-forming materials. In the late stage of orogeny, the Gande-Maduo fault was pushed to the right, and its southern wall strata were dragged and folded, forming a fault-fault system on the axis and wings of the fold. When CO2-NaCl-H2O fluid rich in ore-forming materials enters these fracture-fracture systems, it first reacts with surrounding rocks to form pyrite sericite. When the fluid is cooled, it does not change in the temperature range of 236 ~ 275℃. Ore-forming fluid belongs to H2O-NaCl-CO2 CH4 N2 system with medium temperature and low salinity.
Dachang gold mineralization is closely related to the above orogenic process in time and space, and has typical orogenic characteristics. The deposits (bodies) are located in the fracture zone of large shear zone, reflecting the long-term tectonic activity in the late Indosinian period and the characteristics of multi-source metallogenic hydrothermal transformation.
refer to
Bao Cunyi, Xu Guowu, Chris Lee et al. 2003. Genetic types and metallogenic potential analysis of gold deposits in Dachang area. Brief introduction to Qinghai, (3): 17 ~ 22.
Feng Chengyou, Zhang Dequan, Wang Fuchun, et al. 2004. Geochemical study on ore-forming fluid of orogenic gold (antimony) deposit in East Kunlun, Qinghai Province. Journal of Petrology, 20 (4): 949 ~ 960.
Wang Weiqing, Wang Zengshou, Li Bo. Analysis of ore-controlling factors of Dachang Gold Mine in Qumalai County, Qinghai Province in 2005 and its regional prospecting significance. Brief introduction to Qinghai, (3): 32 ~ 36.
Zhao,,, et al. 2005. Characteristics of fluid inclusions in Dachang gold deposit, Qinghai Province and its geological significance. Geology of mineral deposits, 24 (3): 305 ~ 3 16.
Zhao Junwei, Sun Fengyue, Li Shijin and others, 2007. Geological characteristics of gold (antimony) deposits in turbidite in northern Bayan Kara, Qinghai Province —— Taking Dachang-Jiagelongwa area as an example. Gold, 28 (9): 8 ~ 13.
(Li,, writing)