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Daqingshan Mountains Gold Province - Hadamengou, Saiyinwusu, Wulashan, Chang Shan Hao, Shibaqinghao, Houshihua, Wachanggou, Gongyiming, Laoyanghao, Hijigou, Nalinggou, Donghuofang |
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Inner Mongolia, China |
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Au
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Daqingshan Mountains Gold Province represents the western section of a larger gold province along the northern margin of the North China Craton, defined by an ~1500 km long series of orogenic style lode gold deposits that extends from the middle of Inner Mongolia, through northern Hebei and Liaoning, to Jilin Province. Together they account for more than 900 tonnes (30 Moz) of gold. The Daqingshan Mountains Gold Province includes the Hadamengou, Saiyinwusu, Wulashan,
Chang Shan Hao, Shibaqinghao, Houshihua, Wachanggou, Gongyiming, Laoyanghao, Hijigou and Nalinggou deposits, as well as Donghuofang to the east near Hohhot. These deposits are clustered in a WNW-ESE elongated area of ~200 x 120 km. A representative selection of these deposits are described below.
The northern margin of the North China Craton is characterised by east-west trending basement uplift blocks of metamorphosed Archaean and Palaeoproterozoic gneiss, schist, granulite, amphibolite and banded iron formation that have been episodically uplifted during Variscan (Permo-Carboniferous), Indosinian (Triassic), and Yanshanian (Jurassic to Cretaceous) tectono-magmatic events. Slightly metamorphosed Mesoproterozoic to Neoproterozoic shallow marine quartzite, slate and limestone, and Palaeozoic to Cretaceous shallow marine to continental sedimentary rocks, surround the uplifts. Most of the deposits are hosted by uplifted blocks of Precambrian metamorphic rocks, although Palaeozoic and Mesozoic felsic plutons are commonly found in close proximity and host around 30% of the mineralisation.
Gold deposits and granites are associated with both Variscan and Yanshanian tectonism, although broad scale regional deformation is mainly Variscan and is best characterised by east-west striking folds and fault zones formed during the Permian early stages of ocean closure between the North China and Siberian cratons. Locally, in the eastern part of the gold province, the Variscan structures are overprinted by Yanshanian NNE trending strike slip faults. The Late Jurassic to Early Cretaceous Yanshanian tectonism could have been caused either by the oblique subduction of the Izanagi oceanic plate underneath the North China craton and/or final closure of the Mongolia-Okhotsk ocean between the Siberian and North China cratons.
In the Daqingshan Mountain area, mineralisation, as at the Hadamengou deposit, is controlled by secondary structures in Archaean basement rocks, related to regional east-west striking folds and faults. The deposits are commonly only a few kilometres from Variscan granites, and are hosted in high-grade metamorphic rocks, although no significant gold, has been discovered in the igneous rocks.
This Variscan mineralisation is characterised by pinkish K feldspar-quartz veins. Telluride minerals are common, and proximal alteration zones may contain in excess of 6% K20.
The Hadamengou deposit is located 20 km west of the city of Baotou in Inner Mongolia and is hosted within the Archaean Wulashan Group, which is composed of garnet gneiss, granulite, magnetite-quartzite, and cordierite-, sillimanite-, garnet and graphite-biotite schist, quartzite and marble. The host sequence was metamorphosed to granulite facies during the late Archaean at temperatures of 750 to 850°C and pressures of 7 to 9 kbar, and subsequently underwent retrogression to greenschist to epidote-hornblende facies during the late Proterozoic (Gan et al., 1994). Gold mineralisation is spatially closely associated with magnetite-quartz granulite and magnetite-garnet-plagioclase-quartz gneiss, interpreted to represent metamorphosed banded iron formation (BIF).
The deposit contains >60 t of Au at grades of 8 to 9 g/t Au (Yang et al., 2003) and occurs within an east-west striking, 10 km long and 100 to 400 m wide mylonite zone, the Archaean Daqingshan granulite belt, that is exposed in the mine area (Gan et al., 1994). K feldspar-quartz veins, quartz veins, and altered rocks parallel this structural zone and more regional east-west trending structures. Individual veins are normally 200 to 500 m long, but some extend for 3 km. They average 2 to 3 m in thickness, and have been mined to a depth of 400 m, with little change in ore grade. The veins occur in clusters and swarms in a number of structural slices within the mylonite zone. Three vein/mineralisation types have been recognised: i). quartz veins with gold, quartz, pyrite, chalcopyrite, galena and sphalerite; ii). K feldspar and quartz-K feldspar veins with gold, K feldspar, quartz, pyrite, sericite, chlorite and specularite; and iii). potassic and silica-altered rock with gold, quartz, K feldspar, albite, sericite, chlorite, calcite and pyrite, with minor biotite, magnetite, muscovite and garnet. The principal alteration assemblage includes K feldspar, silica, sericite and carbonate minerals. Gold mineralisation is closely related to K feldspar.
Mineralisation is interpreted to be related to related to the Dongshadegai and Xishadegai intrusions of the Dahuabei granite, and to have formed in an Indosinian Triassic extensional tectonic environment (Jia et al., 2019). The Archaean ductile shear zone is interpreted to have acted as a conduit for fluid flow, while brittle-ductile 'shear zones' developed during Proterozoic retrograde metamorphism acted as the host structures of gold mineralisation introduced during the Triassic structural reactivation and magmatism (Gan et al., 1994). Return to Top
The Saiyinwusu deposit is a few tens of kilometres north of Hademengou, and ~15 km NW of the Bayan Obo REE-Nb-Fe mine. It is only 2 km south of the regional Chifeng-Bayan Obo Fault on the northern edge of the North China craton, and is hosted by Proterozoic metamorphic rocks. The combined resource of the Saiyinwusu and nearby Bayan Obo gold deposits (close to the Bayan Obo REE-Nb-Fe mine) is >20 t Au with grades of 5 to 6 g/t Au.
The district surrounding the deposit comprises weakly-metamorphosed Neoproterozoic to earliest Palaeozoic sandstone, quartzite, dolomite, banded iron formation and carbonaceous slate of the Bayan Obo Group, Jinjiang Formation, regarded as platform cover to the Archaean to Palaeoproterozoic North China Craton. Both Ordovician to Silurian (Caledonian) and 270 to 230 Ma (K-Ar and Rb-Sr) Late Palaeozoic igneous bodies intrude the platform sequence to the south of the Chifeng-Bayan Obo Fault which was periodically strike-slip reactivated during the Mesozoic. The Saiyinwusu orebodies are preferentially located along a more local east-west trending structural zone (deformation dated at 197 Ma; Zhang et al., 1999) on the northern limb of an overturned anticline, controlled by intersections with late NE-trending faults. Some of the gold lodes are found within a foliation-parallel, ductilely-deformed and altered, quartz-rich, biotite granite dyke, known as the 'tectonic felsite'. Three distinct mineralised zones are recognised at Saiyinwusu. The southern (only a few km north of Bayan Obo) and middle zones (proximal to a large fault) are dominated by small veins in limestone and potassium-rich slate, whereas the main northern zone comprises several tens of large massive quartz veins hosted in a variety of the Proterozoic sedimentary rock units and, to a lesser extent, the 'tectonic felsite'. Three veins in the latter are exploited, including the longest ‘#26 vein', that has an 800 m strike length and averages 1 to 2 m in thickness. Numerous low-angle tension gap veins occur within the shear zones or thrust faults. The veins are dominantly massive milky-white to waxy-grey quartz, typically with 1 to 3 vol.% sulphides, characteristically pyrite, galena and arsenopyrite. Higher, up to 15 vol.%, sulphide sections of veins are proximal or within banded iron formation and are relatively richer in arsenopyrite. Gold occurs in its native form and as electrum, and is ~10 vol.% free-milling. Host rocks adjacent to veins average ~1 g/t Au, whereas the veins carry as much as 15 g/t Au. The bulked mineralised veins and wall rocks produce a diluted head grade of 5 to 6 g/t Au. This deposit has locally significant As and Sb enrichments. These veins cut all dykes although steep east-trending strike-slip faults dislocate the lodes. A porphyry-style gold bearing stockwork zone, with extensive associated sericite alteration has also been recognised, but only evaluated in its upper oxide zone (as of 2002). Description after Hart et al. (2002)
Mineralisation at the Late Palaeozoic Hadamengou and Saiyinwusu deposits is association with abundant arsenic- and antimony-bearing sulphide phases, occurs in quartz veins and, less commonly, is disseminated in mylonitic volcanic rocks, along a series of east-west and NE trending, steeply-dipping shear zones. Return to Top
The Wulashan deposits are ~20 km west of Baotou City. They were discovered in 1986 and have become some of the most significant producers in the Daqinshan district. The deposit area is ~8 km long and, 80 to 200 m wide, parallel to a major east-west regional fault zone. More than 25 low sulphide lodes have been recognised, characterised by red, potassium-metasomatised alteration zones, with a resource of ~60 t Au. The orebodies strike east-west and occur in an uplifted block of north-dipping Late Archaean gneiss, amphibolite, migmatite and marble of the Wulashan Group, exposed in the hanging wall, immediately above the Daqinshan-Wulashan regional fault. Archaean basement is intruded by ~1800 Ma Palaeoproterozoic pegmatitic dykes. Post-metamorphic Proterozoic and Phanerozoic plutons, stocks and dykes of dolerite, quartz diorite, granodiorite, diorite porphyry, aplite, pegmatite, biotite, granite and syenite are found within the district (Gan et al., 1994; Nie and Bjorlykke 1994). The most significant of these is a late Paleozoic sub-alkalic suite that includes the 200 km2 Duhaubei batholith and an associated swarm of syenitic dykes. The batholith is expose a few km west of the orebodies and comprises of a medium- to coarse-grained, alkali-feldspar biotite granite that is texturally zoned with a coarser grained centre (Gan et al., 1994). East-west striking, 1 to 7 m wide alkalic and pegmatite dykes persist for several kilometres, following the regional metamorphic grain, parallel and proximal to the ore zones. Dykes and the Dahuabei pluton have been dated between 300 and 270 Ma (-Ar whole rock; Zhang 1991; Zhang et al., 1999), whilst zircon ages indicate an ~350 Ma crystallisation age (SHRIMP U-Pb; Y. Qiu, unpublished data).
Lodes that are 1 to 3 m thick had been mined to depths of ~120 m, hosted within structures that may be traced for as much as 3 km along strike. These lodes contain only a few vol.% sulphides of three types: i). medium-grade (5 to 6 g/t Au); quartz–alkali feldspar pegmatite-like veins; ii). low grade (~1 g/t Au) massive quartz veins; and iii). high-grade (>8 g/t Au) fractured and potassic metasomatised wall rock containing disseminated pyrite. This latter comprises the bulk of the Wulashan resource, and is typically found adjacent to the quartz and pegmatitic quartz-feldspar veins, with widths that are approximately equal to the vein thickness. Pyrite is the dominant metallic mineral, although chalcopyrite and galena are also common, together with minor magnetite, sphalerite, arsenopyrite and bismuthinite. Molybdenite occurs in pegmatitic veins. Gold is found in its native form, with electrum in pyrite or quartz, or as gold–telluride minerals such as calaverite and sylvanite. The gold grade is sympathetic to the sulphide mineral content, but does not apparently change with depth. Gangue minerals include quartz, siderite, cerussite, with various supergene metal oxide minerals; hematite is particularly abundant. Throughout the mineralised zones, alteration dominated by extensive alkali feldspar flooding adjacent to veins, dykes, faults and breccias extends for several metres into the host rocks. This zone is fringed by sericite, chlorite, epidote and calcite forming successive alteration envelopes outward from the veins (Hart et al., 2002). Return to Top
The Chang Shan Hao deposit, which is ~90 km WSW of Bayan Obo is part of the same district and is the subject of a separate record.
The Shibaqinghao or Shiba Qingha is located ~120 km WNW of Hohot and ~100 km SSW of Bayan Obo in Inner Mongolia. It lies within a district Liang and Shuto (1998) describe as being composed of three major basement age groupings: i). pre-Neoarchaean Xia Jining Group metamorphic rocks; ii). Neoarchaean Dongwa Fenzi Group granulite, amphibolite, gneiss and migmatite, including metamorphic rocks such as biotite and biotite-amphibole gneisses and schists, assumed to represent protoliths that were ultramafic (komatiitic) volcanic rocks as well as tholeiitic and alkali basalts, siliceous iron formation, turbidites and acid volcanic rocks; and iii). Palaeoproterozoic Wu Lashan Group sedimentary rocks and K feldspar granite and diorite. Granite bodies that are petrologically similar to Mesozoic granitic rocks scattered outside of the deposit area occur at depths of 200 to 300 m below the deposit.
The Precambrian rocks have been locally subjected to shearing at temperatures of 300 to 350°C and 0.3 to 0.5 GPa to form sericite and chlorite mylonite zones dated at ~2.04 Ga (U-Pb zircon; Li et al., 1987). During the Mesozoic, WNW-ESE directed stress produced a series of folds and faults, all of which trend NNE-SSW, which at Shibaqinghao post-date the mylonites. Mineralisation at Shibaqinghao coincides with an area of mylonitisation that extends over a strike length of 3.5 km and width of 100 to 150 m. These mylonites control the distribution of mineralisation at Shibaqinghao, which is cut by the Mesozoic NNE-SSW structures, although large scale quartz veining is often found at the intersection of the two trends (Liang and Shuto, 1998).
Two types of quartz veining are recognised at Shibaqinghao, i). quartz veins formed before or during ductile deformation, that are usually small, 1 to 10 cm thick and 2 to 20 cm long, are concordant with the mylonite fabric, have been subjected to ductile deformation, and usually carry gold; ii). large veins that are 1 to 10 m thick and 5 to 100 m long, that crosscut the mylonite fabric, are controlled by the NNE-SSW faulting, sometimes preferentially located at the intersection of the two trends (Liang and Shuto, 1998).
Two types of gold ore are recognised, i). ore hosted by the mylonite, with a gangue mineral assemblage that includes amphibole, chlorite, quartz, feldspar, sericite and calcite, enclosing pyrite, sphalerite, chalcopyrite, bornite, arsenopyrite and chalcocite, with gold being intimately associated with the pyrite. Pyrite is the only sulphide coarse enough to be seen by the naked eye. The sulphides both follow the mylonitic fabric and are surrounded by the mylonitic foliation, suggesting formation coeval with deformation. This ore is accompanied by the small syn-deformation quartz veins which also carry auriferous pyrite. ii). quartz-vein ore in large quartz veins which cross-cut and truncate mylonite orebodies. Vein quartz in this style is 90% of the gangue, accompanied by sericite, chlorite, calcite and feldspar, with ore minerals predominantly pyrite and secondary sphalerite, chalcopyrite, bornite, arsenopyrite and chalcocite. Native gold grains are commonly associated with the pyrite, found along fractures and grain boundaries. These sulphides are heterogeneously distributed within the quartz veins, generally varying between 5 and 15%, but locally >50% to massive sulphides (Liang and Shuto, 1998).
Pyrite in the mylonite ores have negative δ34S similar to mantle derived sulphur, while associated Pb isotope compositions are are close to a model curve of mantle evolution. In contrast pyrite associated with native gold in the large quartz veins have positive δ34S values similar to magnetite series granites and Pb isotopes are scattered near a model curve of upper crustal evolution (Liang and Shuto, 1998). Return to Top
The most recent source geological information used to prepare this decription was dated: 2010.
Record last updated: 6/12/2020
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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Gan, S.-F., Qiu, Y.-M., Yang, H.-Y. and van Reenen, D.D., 1994 - The Hadamengou Mine: A Typical Gold Deposit in the Archean Granulite Facies Terrane of the North China Craton: in International Geology Review v.36, pp. 850-866.
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Hart, C.J., Goldfarb, R.J., Qiu, Y., Snee, L., Miller, L.G. and Miller, M.L., 2002 - Gold deposits of the northern margin of the North China Craton: multiple late Paleozoic-Mesozoic mineralizing events: in Mineralium Deposita v.37, pp. 326-351.
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Liang, Y. and Shuto, K., 1998 - S and Pb isotope compositions of the Shiba Qinghao gold deposit in the central Inner Mongolia, China: in Earth Science (Chikyu Kagaku), v.52, pp. 475-485.
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Xu, J., Gu, X., Zhang, Y., Wang, J., He, G., Zhou, C. and Liu, R., 2021 - Geology, fluid inclusions, H-O isotope, and hydrothermal zircon U-Pb geochronology of the Daqingshan orogenic gold deposit in Beishan orogenic belt, Xinjiang, NW China: in Mineralium Deposita v.56, pp. 325-342.
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Yang, J.-H., Wu, F.-Y. and Wilde, S.A., 2003 - A review of the geodynamic setting of large-scale Late Mesozoic gold mineralization in the North China Craton: an association with lithospheric thinning: in Ore Geology Reviews v.23, pp. 125-152.
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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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Zhou, T., Goldfarb, R.J. and Phillips, G.N., 2002 - Tectonics and distribution of gold deposits in China - an overview: in Mineralium Deposita v.37, pp. 249-282.
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