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Jiapigou District - Jiapigou, Haigou, Jiapigoubenqu, Erdaogou, Sandaocha, Xiaobeigou, Banmiaozi, Miaoling, Sidaocha, Daxiangou, Liupiyegou, Hongqigou, Weixiazi, Bajiazi, Erdaodianz |
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Jilin, China |
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Au Ag
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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The Jiapigou Gold Field in southern Jilin Province, China, is located in the easternmost portion of the northern margin of the North China Craton. It is one of the most important gold-producing districts in China, having been responsible for nearly half of China's gold production during the 1960s. The Jiapigou, Erdaogou, Sandaocha, Bajiazi, Banmiaozi, Xiaobeigou, Miaoling, Erdaodianz and Haigou gold deposits, with more than 100 t combined gold resource plus production (Miao et al., 2005), defined the main gold-rich belt in 2005. However, by 2020, according to Zeng et al. (2020), the gold field contained six large deposits (defined as 20 to 100 t of Au) - Haigou, Jiapigoubenqu, Erdaogou, Sandaocha, Xiaobeigou and Banmiaozi; six medium (defined as 5 to 20 t of Au) - Miaoling, Sidaocha, Daxiangou, Liupiyegou, Hongqigou and Weixiazi; and four small gold deposits (<5 t of Au), in addition to ~100 other gold occurrences. Its resources have been estimated at >150 t of contained gold (Zeng et al., 2020).
The Jiapigou Gold Field is part of the greater Changbaishan Mountains Gold Province, and is the northernmost of the districts that make up the province..
Gold deposits in the Jiapigou area are hosted by Archaean metamorphic rocks. These deposits are directly hosted by a shear zone and fault system that defines the boundary between the North China Craton and its bounding orogenic belt to the northeast. They lie within a composite ductile WNW-ESE trending shear zone that is up to 10 km wide cutting late Archaean gneissic tonalite, trondhjemite and granodiorite (TTG) and amphibolite (2523±6 Ma), which have been retrogressed to greenschist facies. The deposits occur as massive auriferous quartz veins that contain sulphides (<10 vol.%) and less commonly disseminated- and stockwork-style mineralisation. The lodes are characterised by high Au/Ag ratios and relatively higher Cu (up to 1.3%) and Pb (as much as 10.3%) contents than most other gold deposits in the NCC. While phyllic assemblages are the main alteration style, potassic and chloritic alteration characterises felsic and mafic host rocks, respectively.
Whist no significant intrusions are recorded in the immediate Jiapigou goldfield, major Mesozoic intrusions form the northern margin of the zone of shearing that hosts the deposits of the Jiapigou Gold Field, and felsic, alkaline and mafic dykes are common, usually occupying the same fault system as the gold lodes. Dykes also locally host gold mineralisation. Zircon SHRIMP U-Pb dates on pre-ore dykes yield ages of around 220 Ma, constraining the maximum age of gold mineralisation, whereas 40Ar/39Ar dates on hydrothermal sericite give an age of approximately 204 Ma suggesting a late Triassic gold-forming event. This timing is coeval with, or slightly later than, the post-orogenic magmatism that followed the final orogenesis of the Inner Mongolian-Daxinganling orogenic belt (IMDOB), which bounds the NCC to the north, suggesting that a post-orogenic tectonic setting is appropriate for the late Triassic gold mineralisation.
As listed above, more than 20 gold deposits and occurrences have been delineated in the Jiapigou area, mainly distributed over a NW-SE trend length of ~20 km with two outliers, Erdaodianzi which is 40 km to the NW and Haigou ~55 km to the ESE. A selection of the more significant deposits are described below:
Jiapigou deposit contains >40 t of Au at grades of 7 to 26 g/t Au, hosted by a 2.6 Ga Neoarchaean suite of plagioclase-amphibole gneiss, amphibolite and tonalite-trondhjemite-granodiorite (TTG) gneiss that underwent high-grade metamorphism at 2.27 Ga. Late- to post Variscan (268 to 201 Ma) biotite granites, Yanshanian (168 to 149 Ma) mafic to granitoid stocks and dykes, including aplite, syenite and diorite, occur frequently within the district. The Huangnihe granitic intrusion, located in the NE, near the Jiapigou mine, has been dated as 166 Ma (Miao, 2000; Luo et al., 2000; Zhang et al., 2002).
Gold mineralisation is associated with zones of strong deformation and alteration that are estimated to have evolved at temperatures of 300 to 500°C and pressures of ~0.3 GPa (Cheng et al., 1996). Discrete mineralised quartz-sulphide veins are hosted in NE to ENE trending ductile shear and alteration zones, striking at 60 to 70° over lengths of 90 to 730 m, with thicknesses of 0.5 to 1.5 m (to a maximum of 17 m), and down-dip extents of 50 to 670 m. More than 20 quartz veins have been outlined, mainly concentrated in three near parallel ENE striking alteration zones, known as the Northern, Middle and Southern zones. The 5 km long and 100 to 300 m wide Middle Zone is the largest, with a strike direction that varies from 45 to 70 to ~80° from the west→central→east and dips of ~20 to 45°SE. The other two zones both strike at 60 to 70° and dip SE, with the Northern having a strike length and width of 1300 x 10 to 50 m and the Southern with 3500 x 30 to 100 m. Dykes of granite, syenite and diorite intrude the mineralised rock, which is also cut and offset by minor NW and NNE faults (Miao et al., 2005).
The mineral assemblage within the veins include - quartz, chlorite, sericite and calcite with native gold, pyrite, chalcopyrite, galena, sphalerite, magnetite, pyrrhotite, wolframite and scheelite. Although phyllic alteration is most common, potassic and chloritic alterations characterise felsic and mafic host rocks, respectively. The ores at Jiapigou contain 0.4 to 10.3 wt.% Pb and 0.1 to 13. wt.% Cu which are higher than most other lode gold deposits of the northern North China Craton (Cheng et al., 1996). There is also a broad mineral zonation along strike, from i). Au-Cu±W in the east, with abundant magnetite and trace wolframite and scheelite; to ii). Au-Cu-Pb±W in the centre with an anomalously high Pb content, accompanied by minor magnetite, wolframite and pyrrhotite; to iii). Pb-Au-Cu±W in the west with very high Pb contents of up to 10.3 wt.% (Cheng et al., 1996) and minor magnetite, wolframite and scheelite (Miao et al., 2005).
Erdaogou, which was discovered in 1909, had production + resources of >40 t of Au at grades of 6 to 19 g/t Au (Hart et al., 2002). It is hosted by the Archaean Jiapigou tholeiitic greenstone belt, which consists of fine grained amphibolites, amphibolitic gneisses and TTG gneisses with associated Archaean potassic granite, granodioritic and quartz-dioritic, dioritic and lamprophyric dykes. These rocks have undergone retrograde metamorphism to a mineral assemblage of chlorite, quartz and calcite with minor plagioclase, amphibole, epidote, talc and magnetite. K feldspar granite batholiths in the deposit area and surrounding district have given a near concordant U-Pb zircon age of 2505±14 Ma (Cheng et al., 1996). Other intrusions in the deposit area include poorly dated quartz diorite, granite, aplite, diorite porphyry and lamprophyre dykes, which are indicated by cross cutting relationships to mostly be post-mineralisation (Hart et al., 2002).
Four main ore zones had been recognised by 2002, each of which is composed of a ductile shear zone with superimposed brittle faults hosting mineralisation that occurs as quartz-sulphide veins and/or disseminated mineralisation, hosted in NW-striking shear zones. The main orebodies strike at 5 to 10° and dip at 55 to 70°SE, varying from 50 to 350 m in length, from 0.4 to 5.2 m in width and from 80 to 500 m in down-dip extent (Hart et al., 2002; Miao , 2005). Zone I occurs over a strike length of 2000 m and a width of 50 m wide, enclosing individual veins that are typically no more than 5 m wide. The economic section of this zone is ~420 m long and persists to a depth of at least 900 m. Mineralisation comprises several percent combined metallic minerals, including native gold, pyrite, chalcopyrite, galena, sphalerite, magnetite, scheelite, argentite and pearceite, in a gangue assemblage of quartz, chlorite, calcite and barite. Grades average 14 g/t Au, with an average of 1 wt.% Pb and ~0.2 wt.% Cu. A >1750 m long and 200 to 500 m wide, Permo-Carboniferous granodiorite dyke forms both the hanging wall and footwall of zone I and cuts the ore zone at 280 m below the surface. This dyke is generally parallel with the gold lode along strike and down dip, and is interpreted by mine staff to have formed coeval to, or slightly after, the gold mineralisation (Hart et al., 2002). Zones II and III each have a strike length of ~700 and are ~3 m thick, but otherwise are similar in style and size to zone I, although with much lower grades of ~4 g/t Au. The alteration associated with Zone IV is more extensive, with fracturing, quartz-sulphide stockworks and disseminated sulphide minerals in the country rocks, and much greater variation of gold grades (Hart et al., 2002).
As at the Jiapigou deposit, there is a mineral zonation, ranging from pyrite dominant upper levels, accompanied by minor galena and chalcopyrite, to predominantly galena with pyrite and chalcopyrite being less abundant deeper in the deposit. According to Hart et al. (2002), the mineral paragenesis of the disseminated mineralisation ranges from early quartz, scheelite, magnetite, and pyrite-sphalerite → chalcopyrite-galena → pyrite-galena → galena → pyrite → chalcopyrite-quartz, with later pyrite and calcite. However, Liang et al. (2016) states that mineralisation in the quartz-sulphide veins took place in four stages: i). milky quartz, ii). pyrite-quartz, iii). native gold-quartz-pyrite, and vi). quartz-carbonate.
Sandaocha with >45 t of Au at grades of 10 to 26 g/t Au, hosted by Archaean amphibolite and TTG rocks with associated dioritic, quartz-syenitic, and lamprophyric dykes. Mineralisation occurs as NNE trending shear zone-hosted gold-bearing quartz veins striking 15 to 30° and dipping 80 to 85°SE. Orebodies vary from 50 to 330 m long, from 1.3 to 3.2 m wide, and from 100 to 300 m in down-dip extent. The mineral assemblages include - quartz, chlorite, sericite and calcite with native gold, pyrite, chalcopyrite, galena, sphalerite, magnetite, bismuthinite and scheelite.
Bajiazi with >20 t of Au at grades of 9 to 37 g/t Au, hosted by Archaean tonalitic gneiss and amphibolite with associated quartz-syenitic, dioritic, and diabase dykes. Mineralisation occurs as gold-bearing quartz veins hosted by NE trending shear zones which are >2.5 km long and 5-12 m wide. Tabular orebodies strike at 50-60° and dip 70-80°SE, varying from 50 to 320 m in length, from 0.2 to 1.7 m in thickness and are from 30 to 240 m in down-dip extent. The mineral assemblages include - quartz, chlorite, sericite, ankerite and calcite with native gold, pyrite, galena, chalcopyrite, sphalerite and scheelite.
Banmiaozi with >15 t of Au at grades of 5 to 30 g/t Au, hosted by Archaean TTG gneiss and amphibolite with associated dioritic, granodioritic, syenitic, granitic, diabase and lamprophyre dykes. Mineralisation occurs as east-west striking shear zones or faults which host the quartz-veins and disseminated alteration ores. Orebodies strike at 275 to 295° and dip 60 to 85°SW, varying from 18 to 370 m in length, from 0.05 to 7 m in width and from 50 to 355 m in down-dip extent. The mineral assemblages include - quartz, chlorite, sericite and calcite with native gold, pyrite, chalcopyrite, specularite, magnetite, galena, hematite and malachite.
Xiaobeigou with 10 t of Au at grades of 17 g/t Au, hosted by Archaean amphibolite and TTG rock with associated syenitic, dioritic, diabase and lamprophyric dykes. Mineralisation occurs as disseminated- and stockwork-style and quartz-vein-style gold ores are hosted in NW-trending shear zone(s). Orebodies, strike at 320 to 330° and dip 65 to 75°NE. They vary from 30 to 100 m in length and from 0.1 to 3.3 m in width. The mineral assemblages include - quartz, chlorite, sericite and calcite with native gold, pyrite, chalcopyrite, magnetite, galena, sphalerite, scheelite, wolframite, specularite, hematite, pyrrhotite and bismuthinite.
Miaoling with >25 t of contained Au at an average grade of 3.2 g/t Au, hosted by Archaean TTG gneiss and amphibolite with associated granodioritic, and dioritic dykes. Mineralisation occurs as disseminated- and stockwork-style gold hosted by NW- to NNW trending shear zones. Major orebodies, strike at 330 to 340° and dip 55 to 65°NE. They are up to 400 m long, 0.4-7 m wide, with a down-dip extent of 50 to 210 m. The mineral assemblages include - quartz, chlorite, sericite and calcite with native gold, pyrite, chalcopyrite, sphalerite, magnetite, galena and hematite.
Erdaodianzi with >40 t of Au at grades of 8 to 15 g/t Au, hosted by Late-Palaeozoic metamorphic rocks of the Hulan Group with associated biotite granite and granodiorite, as well as felsic dykes. Mineralisation occurs as quartz veins hosted in NW- to north striking faults in Palaeozoic metamorphic rocks. Individual lodes range from 55 to 150 m in striking length and 1.9 m in average width. The mineral assemblages include - quartz, sericite, chlorite, calcite and feldspar with native gold, arsenopyrite, pyrite, sphalerite, galena, chalcopyrite and marcasite.
Haigou with >30 t of Au at grades of 21 g/t Au (Hart et al., 2002), hosted by granodiorite with granodiorite and felsic dykes. Mineralisation occurs as quartz veins hosted in NE striking faults within the Haigou granodiorite (a component of the huge Huangnihe granitic batholith). The main lode is up to 930 m long and as wide as 18 m, with a down-dip extent of 300 m, striking 20 to 40° and dipping at 40 to 75°NW. The mineral assemblages include - quartz, sericite, calcite and barite with native gold, pyrite, galena, sphalerite, chalcopyrite, bornite, marcasite, uraninite and pitchblende.
For a broader context see the Changbaishan Mountains Gold Province record.
For further information consult the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 2020.
Record last updated: 8/12/2020
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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Selected References:
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Han, J., Deng, J., Zhang, Y., Sun, J., Wang, Q., Zhang, Y., Zhang, X., Liu, Y., Zhao, F., Wang, L. and Lin, Z., 2022 - Au mineralization-related magmatism in the giant Jiapigou mining district of Northeast China: in Ore Geology Reviews v.141, 19p. doi.org/10.1016/j.oregeorev.2021.104638.
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Miao, L., Qiu, Y., Fan, W., Zhang, F. and Zhai, M., 2005 - Geology, geochronology, and tectonic setting of the Jiapigou gold deposits, southern Jilin Province, China: in Ore Geology Reviews v.26, pp. 137-165.
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Zeng, Q., Wang, Y., Yang, J., Guo, Y., Yu, B., Zhou, L. and Qiu, H., 2020 - Spatial-temporal distribution and tectonic setting of gold deposits in the Northern margin gold belt of the North China Craton: in International Geology Review doi.org/10.1080/00206814.2020.1737839 32p.
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